Battery control method and system

Abstract

The application provides a battery control method and system, based on a whole vehicle positive development process, decomposes battery power demand under different working conditions in a low-temperature environment of the whole vehicle, simultaneously defines available and unavailable electric quantity of the battery in the low-temperature use environment of the whole vehicle, carries out battery test of a certain sample amount, clearly defines the capacity boundary and the power boundary of the battery, completes the capacity boundary and the power boundary integration through a battery management system software, formulates a battery discharge control strategy, ensures that the low-temperature power battery can realize different calibration strategies taking power performance as a main calibration target, taking a cruising range as a main calibration target or taking both power performance and the cruising range into account under the premise of ensuring the safety of the battery use, and further improves the low-temperature safety of the battery.

Description

Technical Field

[0001] This invention relates to the field of batteries, and in particular to a battery control method and system. Background Technology

[0002] With increasing environmental awareness, new energy vehicles have entered a period of rapid development and are being recognized and accepted by more and more consumers. However, due to current limitations in lithium-ion battery technology, solving the low-temperature performance and safety issues of electric vehicles remains a challenge for the industry. At low temperatures, the internal resistance of power batteries deteriorates, leading to greater differences in internal resistance during discharge. This significantly increases the difficulty for the Battery Management System (BMS) to estimate the State of Charge (SOC), resulting in a large deviation in the BMS's prediction of the battery's actual charge and discharge capacity. Consequently, the power battery system is prone to over-discharge and vehicle power loss during discharge.

[0003] For electric vehicles used in low temperatures, most manufacturers choose to avoid the low-temperature operating range of batteries by adding a battery thermal management system. When the battery is cold, the thermal management system is activated to heat the battery, and heating stops when the battery reaches the appropriate operating temperature range, thus ensuring the battery's discharge capacity. However, in actual use, many problems still arise: 1. Heating the battery through the thermal management system is inefficient, and the power required for low-temperature heating is a significant portion, affecting the electric vehicle's low-temperature range; 2. Heating through the thermal management system takes a long time to reach the appropriate operating temperature range from a low temperature. Since commuting time is generally less than one hour for non-long-distance travel, it's possible that the driver has already arrived at their destination while the battery is still heating up, and the vehicle has already shut down before the battery has finished heating. This is considered ineffective heating, resulting in high power consumption for heating and a greater impact on range; 3. The battery temperature read by the BMS is generally the temperature on the module busbar. During low-temperature heating, due to the different specific heat capacities of various components, the temperature on the busbar may not accurately reflect the temperature of the battery cell itself. Therefore, to ensure that the actual discharge demand of the vehicle does not exceed the battery's capacity during battery discharge, a capacity reserve is usually made for the battery. This solution further limits the battery system.

[0004] For example, CN201810289625.2, "A Low-Temperature Charging and Discharging Method for Lithium-ion Batteries," proposes setting different temperature and voltage ranges for the power battery system. By identifying the current battery temperature and voltage state, the cutoff voltage for charging and discharging is determined, and the battery charging and discharging cutoff voltage is continuously adjusted as the battery temperature changes. This method only limits the magnitude of the charging current, without describing the discharge current scheme, and relies solely on the battery voltage to cut off battery discharge. Without effective discharge current control, the battery pack can easily reach the cutoff voltage and stop discharging, failing to effectively guarantee the battery's discharge capacity.

[0005] Therefore, while ensuring battery safety at low temperatures and preventing damage to the battery, how to better utilize battery performance and allow the battery to release as much power as possible at a more reasonable rate is a technical problem that the electric vehicle industry needs to solve. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a battery control method and system that, without requiring excessive external heating, effectively ensures battery discharge safety by defining the available / unavailable capacity of the battery in the vehicle and the power usage method, ensuring that the battery will not be over-discharged, while enabling the battery to effectively improve its discharge power or discharge as much as possible through calibration, thereby improving the battery's low-temperature experience.

[0007] The technical problem solved by this invention is achieved by the following technical solution:

[0008] A battery control method includes: S1: obtaining a first power to meet the needs of high-speed vehicle driving, a second power to meet the needs of medium- and low-speed vehicle driving, and a third power to meet the needs of creeping vehicle driving; and obtaining a fourth, fifth, and sixth power corresponding to the battery cells under different speed requirements of the vehicle based on the overall battery pack structure design; S2: obtaining the room temperature discharge capacity by discharging the battery at a preset rate to a first cutoff voltage; S3: discharging the battery cells at the fourth power to the first cutoff voltage at room temperature to obtain high-speed driving capacity, then discharging at the fifth power to the second cutoff voltage at the target ambient temperature to obtain medium- and low-speed driving capacity, and finally discharging at the fifth power to the second cutoff voltage at the target ambient temperature. The sixth power discharge is carried out to the second cutoff voltage of the target ambient temperature to obtain the unusable power, so as to obtain the usable power and unusable power of the battery at different temperatures. The usable power includes: the high-speed driving power and the medium- and low-speed driving power; S4: According to the usable power and the room temperature discharge capacity, the usable power depth of the battery relative to room temperature is obtained, and according to the usable power, the unusable power and the room temperature discharge capacity, the maximum power depth of the battery relative to room temperature is obtained; S5: According to the remaining capacity of the battery, the usable power depth and the maximum power depth, the discharge boundary of each discharge power of the battery is determined.

[0009] In a preferred embodiment of the present invention, the method further includes: S6: The battery management system sets voltage fault thresholds corresponding to different temperatures and monitors the voltage of the battery in real time to ensure that the dynamic voltage of the battery does not exceed the battery's operating range during charging and discharging.

[0010] In a preferred embodiment of the present invention, step S1 above includes: setting the first power, the second power, and the third power according to vehicle model information and battery characteristics.

[0011] In a preferred embodiment of the present invention, the above-described S2 step includes: at least five batteries or cells used for testing; and the preset rate is 1 / 3C.

[0012] In a preferred embodiment of the present invention, the above-described S3 step further includes: discharging the battery to the cutoff voltage corresponding to the different temperatures using the fourth power, the fifth power, and the sixth power at different temperatures to obtain the usable capacity of the battery at each temperature.

[0013] In a preferred embodiment of the present invention, step S4 above includes: when the remaining capacity of the battery is greater than the difference between the total battery capacity and the available charge depth, the allowable power of the battery can exceed the second power based on the target demand of the vehicle; when the remaining capacity is less than the difference between the total battery capacity and the available charge depth, but greater than the difference between the total battery capacity and the maximum charge depth, the vehicle driving power gradually switches from the second power to the third power, and discharges stably at the third power; when the remaining capacity is less than the difference between the total battery capacity and the maximum charge depth, the allowable discharge power of the battery is limited to 0.

[0014] In a preferred embodiment of the present invention, the method further includes: in a low-temperature environment, the battery only releases the available power at the corresponding temperature; upon receiving an emergency driving demand command, the battery releases the unavailable power at the corresponding temperature.

[0015] A battery control system includes a memory and a processor, wherein the memory stores a battery control program, and when the battery control program is executed by the processor, it implements the steps of the battery control method described above.

[0016] The technical effects achieved by the above-mentioned technical solution of this invention are as follows: Based on the forward development thinking of the whole vehicle, the battery power demand is decomposed through the positioning of the whole vehicle, and the battery usage method at low temperature is determined by the actual battery test data. At different temperatures T, the battery usage is controlled according to the capacity usage boundary and power usage boundary of the battery, which can simultaneously take into account the power and range of the whole vehicle. Due to the reasonable use of battery discharge, the battery's low-temperature lifespan can also be improved, ensuring the safety of battery discharge at low temperatures and improving the driving experience of new energy vehicles without low-temperature heating. Moreover, when the battery is used at low temperatures, if the vehicle's displayed mileage reaches 0, the reserved unusable capacity of the battery can be actively activated to ensure the vehicle's low-speed creep and ensure the safety of the occupants.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating a battery control method according to an embodiment of the present invention;

[0021] Figure 2 A schematic diagram illustrating battery capacity allocation is shown as an embodiment of the present invention;

[0022] Figure 3 A linear relationship between battery usable charge depth and temperature is shown in an embodiment of the present invention.

[0023] Figure 4 This is a flowchart illustrating a process for determining the capacity and power usage boundaries of a battery at low temperatures, as shown in an embodiment of the present invention. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, embodiments of the present invention are described in detail below. Examples of these embodiments are shown 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 are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the embodiments of the present invention. Through the description of the specific embodiments, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve its intended purpose can be obtained. Moreover, the accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

[0025] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0026] It should be understood that although the terms first, second, third, etc., may be used herein to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this document, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if," as used herein, may be interpreted as "when," "when," or "in response to determination." Furthermore, as used herein, the singular forms "a," "an," and "the" are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising," "including," indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or," "and / or," "including at least one of the following," etc., as used in this application, may be interpreted as inclusive, or mean any one or any combination thereof. For example, "including at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Similarly, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Exceptions to this definition only occur when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0027] It should be understood that although the steps in the flowcharts of this application's embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0028] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0029] It should be noted that step designations such as S11 and S12 are used in this document for the purpose of more clearly and concisely describing the corresponding content, and do not constitute a substantial limitation on the order. In specific implementation, those skilled in the art may execute S12 first and then S11, etc., but these should all be within the protection scope of this application.

[0030] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0031] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0032] This invention proposes a method for using power batteries in low-temperature environments based on capacity and power boundaries. Based on the forward development process of a complete vehicle, the battery power requirements under different operating conditions in low-temperature environments are decomposed. Simultaneously, the available / unavailable battery capacity under low-temperature operating conditions is defined, and battery tests with a certain sample size are conducted according to the testing method of this invention to clarify the battery capacity and power boundaries. The power battery system integrates the capacity and power boundaries through the Battery Management System (BMS) software, and formulates a power battery system-level battery strategy for discharge energy flow control. This ensures that, while guaranteeing battery safety, low-temperature power batteries can achieve different calibration strategies, such as prioritizing power performance, prioritizing driving range, or simultaneously considering both power performance and driving range. This method can also further improve battery safety at low temperatures.

[0033] This invention mainly addresses battery discharge solutions when the battery is in a low-temperature and low-charge state; low-temperature charging of the battery is not described in this invention.

[0034] Please see Figure 1 , Figure 1 This is a flowchart illustrating a battery control method according to an embodiment of the present invention.

[0035] like Figure 1 As shown, the battery control method of the present invention includes the following steps:

[0036] S1: Obtain the first power to meet the vehicle's high-speed driving needs, the second power to meet the vehicle's medium-low speed driving needs, the third power to meet the vehicle's creeping driving needs, and obtain the fourth, fifth, and sixth power corresponding to the battery cells to meet the vehicle's different speed requirements based on the overall battery pack structure design.

[0037] Optionally, based on the perspective of vehicle use, the power required for high-speed driving (without affecting the driving experience) / first power P1 is decomposed, the power required for low-speed driving (ensuring the vehicle meets the requirements for general road driving) / second power P2 is decomposed, and the power required for crawling (only ensuring the vehicle can be used for rescue) / third power P3 is decomposed. According to the overall package structure design, the power of the battery cell under different vehicle requirements (P1 / P2 / P3) is decomposed into P4, P5, and P6 (i.e., fourth, fifth, and sixth power).

[0038] S2: Obtain the room temperature discharge capacity by discharging the battery at a preset rate to the first cutoff voltage.

[0039] Optionally, the room temperature capacity of the battery (i.e., the discharge capacity at room temperature RT) is confirmed before discharge control. For example, the battery is discharged to a first cutoff voltage V1 at a preset rate (this rate is constant, 1 / 3C is recommended) to obtain the room temperature discharge capacity CAP_RT. The room temperature discharge capacity of this type of battery is obtained by testing a certain number of samples (e.g., ≥5).

[0040] S3: The battery cell is discharged at a fourth power to a first cutoff voltage at room temperature to obtain high-speed driving power, then discharged at a fifth power to a second cutoff voltage at the target ambient temperature to obtain medium-low speed driving power, and finally discharged at a sixth power to a second cutoff voltage at the target ambient temperature to obtain unusable power, so as to obtain the usable power and unusable power of the battery at different temperatures. The usable power includes: the high-speed driving power and the medium-low speed driving power.

[0041] Optionally, step S3 further includes: discharging the battery to the cutoff voltage corresponding to the different temperatures using the fourth power, fifth power, and sixth power at different temperatures to obtain the usable capacity of the battery at each temperature.

[0042] For example, at different temperatures T, the battery cell is sequentially discharged at a constant power of P4 to the cutoff voltage V1 at ambient temperature RT, yielding the battery capacity CAP_T_1 for high-speed driving. Then, it is discharged at a constant power of P5 to the cutoff voltage V2 at the target ambient temperature T, yielding the battery capacity CAP_T_2 for medium- and low-speed driving. Finally, it is discharged at a constant power of P6 to the cutoff voltage V2 at the target ambient temperature T, yielding the unusable battery capacity CAP_T_3. Thus, at temperature T, the usable battery capacity CAP_T = CAP_T_1 + CAP_T_2; and the unusable battery capacity CAP_T_3. This process is repeated to obtain the usable battery capacity CAP_T and unusable battery capacity CAP_T_3 at different temperatures.

[0043] Please see Figure 2 , Figure 2 This is a schematic diagram illustrating the battery capacity allocation according to an embodiment of the present invention.

[0044] like Figure 2 As shown, based on different driving needs of the vehicle, the battery capacity is defined as available capacity and unavailable capacity. Available capacity (CAP_T) refers to the amount of power that the battery can release when it meets the normal driving / high-speed driving needs of the vehicle (CAP_T_1) or basically meets the low-to-medium speed driving (calibrable) needs of the vehicle (CAP_T_2) (CAP_T=CAP_T_1+CAP_T_2). Unavailable capacity (CAP_T_3) refers to the amount of power that the battery can release when it can only meet the power needs of the vehicle in creep mode (below a certain speed, such as 5kph).

[0045] The available power capacity can at least guarantee the normal driving and acceleration / deceleration requirements of the vehicle. This data is used by the BMS as the basis for SOC capacity estimation. The unavailable capacity is the battery discharge amount under abnormal usage modes and is only used for roadside assistance or activation in emergency situations.

[0046] As we all know, the most crucial component of an electric vehicle is the power battery, and its importance is self-evident. The state of charge (SOC) reading of the power battery is a key aspect of power battery management.

[0047] SOC (State of Charge) reflects the remaining capacity of a battery. It is numerically defined as the ratio of remaining capacity to the battery's total capacity, usually expressed as a percentage. Its value ranges from 0 to 1. SOC = 0 indicates the battery is fully discharged, while SOC = 1 indicates the battery is fully charged.

[0048] Battery state of charge (SOC) cannot be directly measured; it can only be estimated using parameters such as battery terminal voltage, charging / discharging current, and internal resistance. These parameters are also affected by various uncertainties, including battery aging, changes in ambient temperature, and vehicle driving conditions. Therefore, accurate SOC estimation has become a pressing issue in the development of electric vehicles.

[0049] S4: Based on the available power and the room temperature discharge capacity, obtain the battery's available power depth relative to room temperature, and based on the available power, the unavailable power and the room temperature discharge capacity, obtain the battery's maximum power depth relative to room temperature.

[0050] Optionally, through the above tests, the ratio of the cell's usable capacity CAP_T to the usable capacity CAP_RT at different temperatures can be calculated. In the BMS SOC core algorithm, SOC at different temperatures is defined as the usable capacity relative to room temperature. Therefore, the usable capacity (i.e., the depth of usable capacity relative to room temperature) SOC_T when the battery maintains normal driving conditions at temperature T can be calculated as CAP_T / CAP_RT. Please refer to [link to relevant documentation]. Figure 3 ,like Figure 3 As shown in the figure, based on the actual measurement results, as the temperature T increases, the usable SOC_T of the battery at temperature T also gradually increases. SOC_T is the usable SOC of the entire vehicle under normal conditions at different temperatures, and the battery's usage range generally does not exceed this SOC.

[0051] Optionally, the battery control method of the present invention further includes: in a low-temperature environment, the battery only releases the available power at the corresponding temperature; upon receiving an emergency driving demand command, the battery releases the unavailable power at the corresponding temperature.

[0052] For example, if we consider an emergency situation requiring the vehicle to be moved a certain distance (e.g., for repairs, or to find a charging station), the unavailable battery capacity CAP_T_3 measured at P6 power can be released via driver command, ensuring the vehicle can travel at low speed for a short distance. If this capacity is considered, the total battery capacity is CAP = CAP_T + CAP3, and the battery's SOC limit (i.e., the maximum depth of charge relative to room temperature) is SOC_UP = CAP / CAP_RT. Figure 3 As shown.

[0053] S5: Based on the remaining capacity of the battery, the available charge depth, and the maximum charge depth, determine the discharge boundaries for each discharge power of the battery.

[0054] Optionally, step S4 includes: when the remaining capacity of the battery is greater than the difference between the total battery capacity and the available charge depth, the allowable power of the battery can exceed the second power based on the target demand of the vehicle; when the remaining capacity is less than the difference between the total battery capacity and the available charge depth, but greater than the difference between the total battery capacity and the maximum charge depth, the vehicle's driving power gradually switches from the second power to the third power, and discharges stably at the third power; when the remaining capacity is less than the difference between the total battery capacity and the maximum charge depth, the allowable discharge power of the battery is limited to 0.

[0055] Optionally, the battery discharge power mapping discharge boundary is determined based on the data obtained from the above tests. At temperature T, if the current battery SOC ≥ 1 - SOC_T, the allowable driving power is ≥ P2; if the current battery SOC is between 1 - SOC_UP ≤ SOC < 1 - SOC_T, the allowable battery power switches between P3 and P2; if the current battery SOC is lower than 1 - SOC_UP, the current battery discharge capacity is considered weak and cannot meet the vehicle's creep requirements, the battery stops discharging and requires charging.

[0056] Discharge power boundary requirements at different temperatures T:

[0057]

[0058] Optionally, the above discharge power boundary can ensure that the battery is within the cell testing capability and that the battery does not over-discharge when the cell is in normal condition.

[0059] Optionally, the method of the present invention further includes: S6: The battery management system sets voltage fault thresholds corresponding to different temperatures and monitors the voltage of the battery in real time to ensure that the dynamic voltage of the battery does not exceed the battery's operating range during charging and discharging.

[0060] Optionally, the BMS also adds voltage monitoring and fault handling, and sets different voltage fault thresholds based on different temperatures to ensure that the dynamic voltage of the battery does not exceed the battery's operating range during charging and discharging, thus ensuring battery safety.

[0061] Optionally, the control parameters and descriptions in each step of the present invention are shown in the table below.

[0062]

[0063] Optionally, step S1 includes: setting the first power, the second power, and the third power according to the vehicle model information and battery characteristics.

[0064] It should be noted that the system defines P1 / P2 / P3 values ​​based on different vehicle models and their different positioning.

[0065] For example, if you want to ensure the vehicle's low-temperature performance and improve the driving experience, you should prioritize increasing the P1 / P2 value to ensure that the vehicle's driving mapping is at a high level. If P1 / P2 is large, it will lead to increased battery low-temperature polarization, which will affect the battery's low-temperature discharge capacity. However, P3 can be considered at the same time to ensure that as much creeping power can be released as possible after the P2 power discharge.

[0066] For example, if the goal is to ensure the vehicle's range at low temperatures and address the issue of significant range degradation at low temperatures, then it is advisable to prioritize reducing the P1 / P2 values ​​to meet range requirements, reduce battery polarization at low temperatures, and increase the battery's usable capacity at low temperatures.

[0067] In summary, by making reasonable adjustments to P1 / P2 / P3, it is possible to adapt to vehicle configurations that prioritize power, range, or a balance between power and economy. At the same time, by limiting the discharge power mapping boundary, it is possible to ensure safe battery discharge and prevent issues such as undervoltage or over-discharge.

[0068] The battery control method described in this invention is a forward development method. By determining the capacity and power usage boundaries of the battery at low temperatures, it ensures that the battery achieves both overall vehicle performance and low-temperature discharge safety at low temperatures. The main workflow is as follows: Figure 4 As shown.

[0069] First, the power requirements of the whole vehicle are decomposed to obtain the power requirements of the battery system P1 / P2 / P3. Then, based on the battery system design, the power requirements of the battery are further decomposed to the cell level, namely the power requirements of the cell level P4 / P5 / P6. Based on a certain number of cell sample tests, the battery's usable capacity at temperature T and the maximum usable capacity of the battery relative to room temperature are obtained by discharging P4 / P5 / P6 at different cutoff voltages at different temperatures T, thus clarifying the boundary of the battery's usable capacity.

[0070] Secondly, in addition to capacity boundary control, power boundary control is added. When the battery SOC is above 1-SOC_T, the allowable power of the battery can exceed P2 based on the target demand of the vehicle. When the battery SOC is within the range of (1-SOC_T, 1-SOC_UP), the allowable power of the vehicle gradually switches from P2 to P3 and discharges stably at P3. To avoid over-discharge of the battery during micro-discharge at low temperatures, when the battery SOC is below 1-SOC_T, the allowable discharge power of the battery is limited to 0.

[0071] The difference in this case lies in the decomposition of the vehicle's different power demands and the corresponding power required by the battery based on different vehicle operating conditions (high-speed driving, medium-low speed driving, and crawling); obtaining the discharge capacity of the battery to a preset cutoff voltage under different vehicle operating conditions at different battery temperatures, thereby calculating the usable and unusable battery capacity at different temperatures; calculating the usable SOC and SOC usage limit at different temperatures; developing a battery discharge power mapping, and determining the allowable battery power to drive the vehicle under different operating conditions based on the relationship between the current SOC, usable SOC, and SOC usage limit; this case uses vehicle positioning... This study decomposes battery power requirements and determines battery usage methods at low temperatures based on actual battery test data. This ensures battery safety during low-temperature discharge and improves the driving experience of new energy vehicles without low-temperature heating. Furthermore, it proposes battery usage schemes with capacity and power usage boundaries at different temperatures (T). Through reasonable calibration, both vehicle power and range can be balanced. Reasonable use of battery discharge also extends battery life at low temperatures. Moreover, when the vehicle's mileage display reaches 0 during low-temperature use, the system can actively activate the battery's reserved unusable capacity to ensure low-speed crawling and passenger safety.

[0072] This invention's battery control method proposes battery usage schemes with capacity and power usage boundaries at different temperatures (T). Based on a certain sample size of battery data, it clarifies the lower limit of battery capacity and power usage methods at low temperatures. Furthermore, it can calibrate different battery power requirements based on different vehicle models, determining different capacity and power usage boundaries. This allows vehicles to be configured with different priorities: power performance, range performance, or a balance of both, while ensuring safe battery discharge. The method defines the battery's usable and unusable capacity. During normal driving in low-temperature environments, only the usable capacity is used. If the driver has an emergency driving need, the unusable capacity can be released via active command to ensure vehicle operation.

[0073] The present invention also provides a battery control system, the battery control system comprising: a memory and a processor, wherein the memory stores a battery control program, and when the battery control program is executed by the processor, it implements the steps of the battery control method as described in any one of the above.

[0074] The present invention also provides a computer-readable storage medium storing a battery control program, which, when executed by a processor, implements the steps of the method in any of the above embodiments.

[0075] The embodiments of the battery control system and computer-readable storage medium provided in this application include all the technical features of the embodiments of the above-described battery control method. The extended and explanatory content of the specification is basically the same as that of the embodiments of the above-described method, and will not be repeated here.

[0076] This invention also provides a computer program product, which includes computer program code. When the computer program code is run on a computer, it causes the computer to perform the methods described in the various possible implementations above.

[0077] This application also provides a chip, including a memory and a processor. The memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that a device with the chip installed performs the methods described in the various possible implementations above.

[0078] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments of the present invention can be implemented in hardware or by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of the embodiments of the present invention can be embodied in the form of a software product. This software product can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods described in the various implementation scenarios of the embodiments of the present invention.

[0079] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. The above embodiments and accompanying drawings are exemplary. The modules or processes in the accompanying drawings are not necessarily necessary for implementing the embodiments of the present invention and should not be construed as limiting the present invention. Within the scope of the technical concept of the present invention, various simple modifications and combinations can be made to the technical solutions of the present invention, and these simple modifications and combinations all fall within the protection scope of the present invention.

Claims

1. A battery control method, characterized in that, The battery control method includes: S1: Obtain the first power to meet the vehicle's high-speed driving needs, the second power to meet the vehicle's medium-low speed driving needs, the third power to meet the vehicle's creeping driving needs, and obtain the fourth, fifth, and sixth power corresponding to the battery cells to meet the vehicle's different speed requirements based on the overall battery pack structure design. S2: Obtain the room temperature discharge capacity by discharging the battery at a preset rate to the first cutoff voltage; S3: The battery cell is discharged at a fourth power to the first cutoff voltage at room temperature to obtain high-speed driving power, then discharged at a fifth power to the second cutoff voltage at the target ambient temperature to obtain medium-low speed driving power, and finally discharged at a sixth power to the second cutoff voltage at the target ambient temperature to obtain unusable power, so as to obtain the usable power and unusable power of the battery at different temperatures. The usable power includes: the high-speed driving power and the medium-low speed driving power. S4: Based on the available power and the room temperature discharge capacity, obtain the battery's available power depth relative to room temperature, and based on the available power, the unavailable power and the room temperature discharge capacity, obtain the battery's maximum power depth relative to room temperature; S5: Based on the remaining capacity of the battery, the available charge depth, and the maximum charge depth, determine the discharge boundaries for each discharge power of the battery.

2. The battery control method as described in claim 1, characterized in that, The method further includes: S6: The battery management system sets voltage fault thresholds corresponding to different temperatures and monitors the battery voltage in real time to ensure that the dynamic voltage of the battery does not exceed the battery's operating range during charging and discharging.

3. The battery control method as described in claim 1, characterized in that, Step S1 includes: Based on the vehicle model information and battery characteristics, the first power, second power, and third power are set.

4. The battery control method as described in claim 1, characterized in that, Step S2 includes: The batteries or cells used for testing must be at least five in number; The preset rate is 1 / 3C; where C is the charge / discharge rate, and the value of the charge / discharge rate is the ratio of the charge / discharge current to the rated capacity.

5. The battery control method as described in claim 1, characterized in that, The S3 step also includes: The usable capacity of the battery at each temperature is obtained by discharging it to the cutoff voltage corresponding to the fourth, fifth, and sixth power at different temperatures.

6. The battery control method as described in claim 1, characterized in that, The S4 step includes: When the remaining capacity of the battery is greater than the difference between the total battery capacity and the available charge depth, the allowable power of the battery can exceed the second power based on the target demand of the vehicle. When the remaining capacity is less than the difference between the total battery capacity and the available charge depth, and greater than the difference between the total battery capacity and the maximum charge depth, the vehicle's driving power gradually switches from the second power to the third power, and discharges stably at the third power. When the remaining capacity is less than the difference between the total battery capacity and the maximum charge depth, the allowable discharge power of the battery is limited to 0.

7. The battery control method as described in claim 1, characterized in that, The method further includes: In low-temperature environments, the battery only releases the usable electrical charge at the corresponding temperature; Upon receiving an emergency driving request command, the battery releases the unavailable power at the corresponding temperature.

8. A battery control system, characterized in that, The battery control system includes a memory and a processor, wherein the memory stores a battery control program, and when the battery control program is executed by the processor, it implements the steps of the battery control method as described in any one of claims 1 to 7.

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