Method and apparatus for state of charge regulation of a battery system

Abstract

This application provides a method and apparatus for adjusting the state of charge (SOC) of a battery system, comprising: acquiring a target cumulative throughput of the battery system during its service life; establishing battery aging curves for a first battery system and a second battery system under different SOCs, wherein the battery aging curves represent the mapping relationship between the remaining battery capacity and the cumulative throughput; determining multiple target throughput segment intervals and the corresponding battery aging curves for each target throughput segment interval based on the battery aging curves for the first and second battery systems under different SOCs; determining a target throughput interval corresponding to the target cumulative throughput; and adjusting the SOC of the first battery system or the second battery system based on the battery aging curve corresponding to the target throughput interval. This application not only improves the accuracy of the overall SOC assessment of the battery system but also ensures that the battery system maintains maximum capacity release while remaining unaffected by aging batteries.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and more specifically, to a method and apparatus for regulating the state of charge of a battery system. Background Technology

[0002] With the rapid development and widespread adoption of electric vehicles, users are placing increasingly higher demands on battery safety performance. Currently, the power batteries used in electric vehicles are mainly divided into lithium iron phosphate (LFP) batteries and ternary lithium batteries (NCM).

[0003] In the prior art, because LFP has a better safety performance, the state of charge of LFP is often used to reflect the state of charge of the battery system composed of LFP and NCM. The specific method is to dynamically adjust the state of charge range of LFP so that the state of charge of LFP can always reflect the overall state of charge of the battery system.

[0004] However, since the battery system is composed of two types of batteries connected in series, the aging rates of batteries of different types are quite different. The above-mentioned use of LFP's state of charge to reflect the overall state of charge of the battery system will still lead to a certain error in the overall state of charge assessment of the battery system. At the same time, the different states of charge of batteries with different aging rates will affect the service life of the battery system when performing state of charge matching. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a method and apparatus for adjusting the state of charge of a battery system, which can not only improve the accuracy of the overall state of charge assessment of the battery system, but also ensure that the battery system is not affected by aging batteries while maintaining maximum capacity release, thereby improving the service life of the battery system.

[0006] In a first aspect, embodiments of this application provide a method for regulating the state of charge (SOC) of a battery system, wherein the battery system includes a first battery cell and a second battery cell connected in series, and the method includes:

[0007] Obtain the target cumulative throughput of the battery system over its lifespan;

[0008] Establish battery aging curves for the first and second battery systems under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput.

[0009] Based on the battery aging curves of the first system battery and the second system battery under different states of charge, multiple target throughput segment intervals and the corresponding battery aging curves for each target throughput segment interval are determined.

[0010] The target throughput range corresponding to the target cumulative throughput is determined from the throughput ranges corresponding to multiple battery aging curves, and the state of charge of the first system battery or the second system battery is adjusted according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

[0011] In one optional embodiment of this application, the step of obtaining the target cumulative throughput of the battery system over its service life includes:

[0012] Obtain the standard driving conditions during the lifespan of new energy vehicles to obtain the correlation between battery power and time in the battery system;

[0013] Based on the battery power and time of the battery system, calculate the target cumulative throughput of the battery system during its service life.

[0014] In one optional embodiment of this application, the step of establishing battery aging curves for the first battery system and the second battery system under different states of charge includes:

[0015] A first aging curve for the first system battery under a first state of charge, a second aging curve for the first system battery under a second state of charge, and a third aging curve for the second system battery under a second state of charge are established respectively; wherein, the aging rate of the first system battery is greater than the aging rate of the second system battery, and the depth of discharge corresponding to the first state of charge is less than the depth of discharge corresponding to the second state of charge.

[0016] In one optional embodiment of this application, the first state of charge is determined by the following steps:

[0017] Determine the first initial capacity of the first battery system and the second initial capacity of the second battery system; wherein the first initial capacity is greater than the second initial capacity;

[0018] The depth of discharge of the first battery system is determined based on the ratio between the second initial capacity and the first initial capacity, so as to determine the first state of charge based on the depth of discharge.

[0019] In one optional embodiment of this application, the step of determining multiple target throughput segment intervals and the corresponding battery aging curve for each target throughput segment interval based on the battery aging curves of the first battery system and the second battery system under different states of charge includes:

[0020] The first throughput segment boundary value is determined based on the second aging curve of the first system battery under the second state of charge and the third aging curve of the second system battery under the second state of charge.

[0021] Based on the first aging curve of the first system battery under the first state of charge and the second aging curve of the first system battery under the second state of charge, the second throughput segment boundary value is determined; wherein, the first throughput segment boundary value is less than the second throughput segment boundary value.

[0022] Based on the determined first and second throughput segment boundary values, the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are obtained.

[0023] The battery aging curves corresponding to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are determined respectively; wherein, the battery aging curve corresponding to each target throughput segment interval includes a portion of the first aging curve, a portion of the second aging curve, and a portion of the third aging curve.

[0024] In one optional embodiment of this application, the step of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, includes:

[0025] When the target cumulative throughput is not greater than the first throughput segment boundary value, the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

[0026] In one optional embodiment of this application, the step of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, includes:

[0027] When the target cumulative throughput is greater than the first throughput segment boundary value and not greater than the second throughput segment boundary value, if the actual throughput of the battery system during its service life is less than the first throughput segment boundary value, then the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

[0028] Alternatively, if the actual throughput is equal to the first throughput segment boundary value, then the state of charge of the control battery system remains unchanged.

[0029] Alternatively, if the actual throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, then the state of charge of the second system battery is adjusted according to the second aging curve of the first system battery under the second state of charge.

[0030] In one optional embodiment of this application, the step of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, includes:

[0031] When the target cumulative throughput is greater than the second throughput segment boundary value, the state of charge of the second system battery is adjusted according to the first aging curve of the first system battery under the first state of charge.

[0032] In one optional embodiment of this application, the method further includes:

[0033] If the remaining battery capacity of the battery system is detected to be no greater than a preset remaining capacity threshold, then the battery system is determined to have reached the end of its lifespan; wherein, the preset remaining capacity threshold is determined based on a preset weight and the second initial capacity of the second battery system.

[0034] Alternatively, if the depth of discharge corresponding to the adjusted state of charge of the second battery system is not greater than a preset depth threshold, then the battery system is determined to have reached the end of its lifespan.

[0035] Secondly, embodiments of this application also provide a state-of-charge (SOC) regulation device for a battery system, the battery system comprising a first battery cell and a second battery cell connected in series, the device comprising:

[0036] Throughput acquisition module is used to acquire the target cumulative throughput of the battery system during its service life;

[0037] The curve establishment module is used to establish battery aging curves for the first system battery and the second system battery under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput.

[0038] The curve segmentation module is used to determine multiple target throughput segment intervals and the corresponding battery aging curves for each target throughput segment interval based on the battery aging curves of the first system battery and the second system battery under different states of charge.

[0039] The state adjustment module is used to determine the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjust the state of charge of the first system battery or the second system battery according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

[0040] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a memory, and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the memory via the bus, and when the machine-readable instructions are executed by the processor, the steps of the method described above are performed.

[0041] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the method described above.

[0042] This application provides a method and apparatus for adjusting the state of charge (SOC) of a battery system. Compared with the prior art that uses the SOC of the battery pack (LFP) to reflect the overall SOC of the battery system, this application first determines the target throughput range corresponding to the target cumulative throughput of the battery system. Then, based on the battery aging curve corresponding to the target throughput range, it adjusts the SOC of the first or second battery pack to ensure that the first and second battery packs in the battery system maintain the same remaining capacity under the same cumulative throughput. The battery aging curve represents the mapping relationship between the remaining battery capacity and the cumulative throughput. This method not only improves the accuracy of the overall SOC assessment of the battery system but also ensures that the battery system maintains maximum capacity release without being affected by aging batteries, avoiding rapid degradation of the remaining battery capacity and further improving the service life of the battery system.

[0043] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart of a method for adjusting the state of charge of a battery system provided in an embodiment of this application;

[0046] Figure 2 A schematic diagram of battery aging curves under different states of charge for a battery system provided in an embodiment of this application;

[0047] Figure 3This is a schematic diagram of the structure of a state-of-charge regulation device for a battery system provided in an embodiment of this application;

[0048] Figure 4 A schematic diagram of the structure of another battery system state-of-charge regulation device provided in an embodiment of this application;

[0049] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0051] In existing technologies, due to the superior safety performance of light-emitting polymer (LFP) batteries, the state of charge (SOC) of LFPs is often used to reflect the SOC of a battery system composed of LFPs and non-metallic polymer (NCM) batteries. Specifically, this is achieved by dynamically adjusting the SOC range of the LFPs to ensure that the LFP SOC always reflects the overall SOC of the battery system. However, since the battery system consists of two battery systems connected in series, and these different systems have significantly different aging rates, using the LFP SOC to reflect the overall SOC of the battery system still leads to some error in the overall SOC assessment. Furthermore, the different SOCs of batteries with different aging rates can affect the lifespan of the battery system when performing SOC matching.

[0052] Based on this, embodiments of this application provide a method and apparatus for adjusting the state of charge of a battery system, which can not only improve the accuracy of the overall state of charge assessment of the battery system, but also ensure that the battery system is not affected by aging batteries while maintaining maximum capacity release, thereby improving the service life of the battery system.

[0053] Please see Figure 1 , Figure 1This is a flowchart illustrating a method for adjusting the state of charge (SOC) of a battery system according to an embodiment of this application. Here, the battery system includes a first battery cell and a second battery cell connected in series. For example, the first battery cell can be a ternary lithium battery (NCM), and the second battery cell can be a lithium iron phosphate (LFP) battery. The hybrid battery system using the first and second battery cells connected in series has the following advantages: improved SOC estimation accuracy of the LFP battery; increased overall pack energy to improve vehicle range; and improved system insulation performance combined with optimized thermal management strategies.

[0054] This application uses an example of a battery system comprising a first battery cell and a second battery cell connected in series for illustration. Figure 1 As shown in the embodiments of this application, the method includes:

[0055] S101. Obtain the target cumulative throughput of the battery system during its service life.

[0056] In step S101, the step of obtaining the target cumulative throughput of the battery system during its service life includes:

[0057] Step 1011: Obtain the cycle life simulation of the battery system during its service life. The cycle life simulation is used to represent the relationship between the battery power and time of the battery system.

[0058] The service life refers to the lifespan defined at the time of manufacture of the battery system, which is determined through extensive testing and can also be called the warranty period. Cycle life simulation refers to a method of simulating battery life by dynamically updating the battery model parameters based on actual battery test data. For example, the basic battery model can be the Olivier-Louis battery model. First, the boundary conditions of the basic model are given, and experimental verification is performed. The results show that the model can achieve good accuracy in both constant current and dynamic charge-discharge simulations and can be used for battery life simulation. When performing battery cycle life simulation, the relationship between battery power and time can be obtained.

[0059] Step 1012: Calculate the target cumulative throughput of the battery system during its service life based on the battery power and time of the battery system.

[0060] Specifically, the target cumulative throughput of the battery system over its lifespan is calculated using the following formula:

[0061] ;

[0062] Where E0 represents the target cumulative throughput, P represents the battery power of the battery system, and t represents time.

[0063] S102. Establish battery aging curves for the first system battery and the second system battery under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput.

[0064] Here, State of Charge (SOC) is a physical quantity that reflects the remaining capacity of a battery, representing the ratio of the remaining capacity after discharge to its capacity when fully charged; Cumulative throughput refers to the cumulative capacity or energy of the battery system during use; Remaining battery capacity refers to the remaining battery capacity as the discharge time progresses during the discharge process; The battery aging curve reflects the aging rate of the battery and is used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput. In this embodiment, the battery aging curve shows an inverse proportional relationship, with the remaining battery capacity gradually decreasing as the cumulative throughput increases.

[0065] In step S102, a first aging curve of the first system battery under a first state of charge, a second aging curve of the first system battery under a second state of charge, and a third aging curve of the second system battery under a second state of charge are established respectively; wherein, the aging rate of the first system battery is greater than the aging rate of the second system battery, and the depth of discharge corresponding to the first state of charge is less than the depth of discharge corresponding to the second state of charge.

[0066] The depth of discharge (DOD) is the percentage of a battery's discharged capacity relative to its rated capacity. For example, 100% DOD means 100% depth of discharge, meaning the battery is fully charged and then completely discharged each time; 70% DOD means the battery's maximum capacity is reduced to 70% of its original capacity. The sum of DOD and SOC is 1.

[0067] Here, because the aging rate of the first battery system is greater than that of the second battery system, in order to ensure that the first and second battery systems in the battery system maintain the same remaining battery capacity under the same cumulative throughput, the first initial capacity of the first battery system needs to be set greater than the second initial capacity of the second battery system. Specifically, the first initial capacity of the first battery system refers to the battery capacity corresponding to the start of life (BOL), and the second initial capacity of the second battery system refers to the battery capacity corresponding to the start of life (BOL).

[0068] Therefore, in this embodiment of the application, step S102 determines the first state of charge through the following steps:

[0069] Determine the first initial capacity of the first battery system and the second initial capacity of the second battery system;

[0070] The depth of discharge of the first battery system is determined based on the ratio between the second initial capacity and the first initial capacity, so as to determine the first state of charge based on the depth of discharge.

[0071] For example, taking a ternary lithium battery (NCM) as the first battery system and a lithium iron phosphate battery (LFP) as the second battery system, the initial capacity of the NCM is... The second initial capacity of LFP is , If the initial DOD of LFP is 100%, then the initial DOD of NCM is X%.

[0072] S103. Based on the battery aging curves of the first system battery and the second system battery under different states of charge, determine multiple target throughput segment intervals and the battery aging curve corresponding to each target throughput segment interval.

[0073] In this embodiment of the application, step S103 specifically includes:

[0074] Step 1031: Determine the first throughput segment boundary value based on the second aging curve of the first system battery under the second state of charge and the third aging curve of the second system battery under the second state of charge.

[0075] Specifically, the cumulative throughput corresponding to the condition that the remaining capacity of the first battery system under the second state of charge and the remaining capacity of the second battery system under the second state of charge are both equal to the first remaining capacity is determined as the first throughput segment boundary value. In particular, the first throughput segment boundary value and the first remaining capacity can be obtained by determining the intersection point of the second aging curve and the third aging curve.

[0076] Step 1032: Determine the second throughput segment boundary value based on the first aging curve of the first system battery under the first state of charge and the second aging curve of the first system battery under the second state of charge; wherein, the first throughput segment boundary value is less than the second throughput segment boundary value.

[0077] Specifically, the cumulative throughput corresponding to the condition that the remaining capacity of the first system battery in the second state of charge and the remaining capacity of the first system battery in the first state of charge are both equal to the second remaining capacity is defined as the second throughput segment boundary value. In particular, the second throughput segment boundary value and the second remaining capacity can be obtained by determining the intersection point of the first aging curve and the second aging curve.

[0078] Step 1033: Based on the determined first throughput segment boundary value and second throughput segment boundary value, obtain the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval.

[0079] The cumulative throughput is divided according to the first throughput segment boundary value and the second throughput segment boundary value. The range of the first throughput segment interval is the cumulative throughput that is not greater than the first throughput segment boundary value; the range of the second throughput segment interval is the cumulative throughput that is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value; and the range of the third throughput segment interval is the cumulative throughput that is greater than the second throughput segment boundary value.

[0080] Step 1034: Determine the battery aging curves corresponding to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval, respectively; wherein, the battery aging curve corresponding to each target throughput segment interval includes a portion of the first aging curve, a portion of the second aging curve, and a portion of the third aging curve.

[0081] In step 1034, the first aging curve, the second aging curve, and the third aging curve are divided according to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval, respectively, to obtain the battery aging curves corresponding to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval, respectively. Here, the battery aging curve corresponding to each target throughput segment interval (first throughput segment interval, second throughput segment interval, or third throughput segment interval) includes a part of the first aging curve, a part of the second aging curve, and a part of the third aging curve.

[0082] For example, through laboratory cycle life simulation tests based on vehicle operating conditions, a first aging curve (which can be represented as NCM X% DOD aging curve Y1) for the first battery system under the first state of charge, a second aging curve (which can be represented as NCM 100% DOD aging curve Y2) for the first battery system under the second state of charge, and a third aging curve (which can be represented as LFP 100% DOD aging curve Y3) for the second battery system under the second state of charge are established. Figure 2 As shown, C represents the remaining capacity of the battery, E represents the cumulative throughput, and the first initial capacity of the NCM 100% DOD aging curve Y2 is... The second initial capacity of LFP 100% DOD aging curve Y3 is Assuming 100Ah If the capacity is 50 Ah, then the initial capacity of the NCMX% DOD aging curve Y1 is also 50 Ah. Figure 2 It can be known that, according to Figure 2The intersection point A of the 100% DOD aging curve Y2 of NCM and the 100% DOD aging curve Y3 of LFP is represented as (E1, The first throughput segment boundary value is determined; the positional relationship of point B, the intersection of the NCM X% DOD aging curve Y1 and the NCM 100% DOD aging curve Y2, can be expressed as (E2, The second throughput segment boundary value was determined. Among them, the slopes of Y1, Y2, and Y3 all represent the aging rate of the battery. It can be seen that the aging rate of the battery is different under different states of charge (depth of discharge).

[0083] Among them, according to Figure 2 The relationships between the NCM X% DOD aging curve Y1, the NCM 100% DOD aging curve Y2, and the LFP 100% DOD aging curve Y3 can be established as follows:

[0084] The relationship between the NCM100% DOD aging curve Y2 and the formula is: ;

[0085] The relationship for the LFP100%DOD aging curve Y3 is: ;

[0086] The relationship between NCM X%DOD aging curve Y1 is: .

[0087] S104. Determine the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to the multiple battery aging curves, and adjust the state of charge of the first system battery or the second system battery according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

[0088] In one embodiment, when the target cumulative throughput is not greater than the first throughput segment boundary value, the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

[0089] by Figure 2 The schematic diagram of the battery aging curves of the battery system under different states of charge is shown as an example for illustration. Therefore, throughout the entire warranty period, the actual depth of discharge of the first system battery (NCM) is adjusted in real time based on the current remaining capacity of the second system battery (LFP), that is:

[0090] = ;

[0091] Once the actual depth of discharge of the first system cell (NCM) is obtained, the current state of charge of the first system cell (NCM) can be adjusted in real time.

[0092] In another embodiment, when the target cumulative throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, if the actual throughput of the battery system during its service life is less than the first throughput segment boundary value, then the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge; or, if the actual throughput is equal to the first throughput segment boundary value, then the state of charge of the battery system is kept unchanged; or, if the actual throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, then the state of charge of the second system battery is adjusted according to the second aging curve of the first system battery under the second state of charge.

[0093] by Figure 2 The schematic diagram of the battery aging curves of the battery system under different states of charge is shown as an example for illustration. Then when the actual throughput At that time, the actual depth of discharge of the first system battery (NCM) is adjusted in real time based on the current remaining capacity of the second system battery (LFP), that is:

[0094] = ;

[0095] When the actual throughput hour, B% = 100%;

[0096] When the cumulative throughput of the first-system battery (NCM) reaches At this point, it is necessary to adjust the actual depth of discharge of the second-system battery (LFP) to match the remaining capacity of the second-system battery (LFP), that is:

[0097] = .

[0098] Once the actual depth of discharge of the second-system battery (LFP) is obtained, the current state of charge of the second-system battery (LFP) can be adjusted in real time.

[0099] In another embodiment, when the target cumulative throughput is greater than the second throughput segment boundary value, the state of charge of the second system battery is adjusted according to the first aging curve of the first system battery under the first state of charge.

[0100] by Figure 2 The schematic diagram of the battery aging curves of the battery system under different states of charge is shown as an example for illustration. Therefore, the actual depth of discharge of the second-system battery (LFP) needs to be adjusted in real time according to the remaining capacity of the first-system battery (NCM), that is:

[0101] = ;

[0102] Once the actual depth of discharge of the second-system battery (LFP) is obtained, the current state of charge of the second-system battery (LFP) can be adjusted in real time.

[0103] In related solutions, since the battery lifespan varies under different states of charge, defining the lifespan boundary of the battery system is a pressing technical problem that needs to be solved. Based on this, the embodiments of this application propose the following solution:

[0104] In one embodiment, if the remaining battery capacity of the battery system is detected to be no greater than a preset remaining capacity threshold, the battery system is determined to have reached the end of its lifespan; wherein the preset remaining capacity threshold is determined based on a preset weight and the second initial capacity of the second battery system.

[0105] Here, the preset remaining capacity threshold is calculated based on the product of the preset weight and the second initial capacity of the second system battery.

[0106] For example, the battery system can be defined as reaching the end of life (EOL) when the remaining battery capacity is 65% of the second initial capacity of the second battery system.

[0107] In another embodiment, if the depth of discharge corresponding to the adjusted state of charge of the second battery system is not greater than a preset depth threshold, the battery system is determined to have reached the end of its life.

[0108] Here, the adjusted state of charge of the second battery system includes two cases: First, when the target cumulative throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, the state of charge of the second battery system is adjusted according to the second aging curve of the first battery system under the second state of charge; Second, when the target cumulative throughput is greater than the second throughput segment boundary value, the state of charge of the second battery system is adjusted according to the first aging curve of the first battery system under the first state of charge.

[0109] Here, the battery system composed of a first-system battery (NCM) and a second-system battery (LFP) connected in series considers the following characteristics of the State of Charge (SOC) of LFPs: the 20%~95% range is a plateau region. When the lower limit of the SOC falls above 20%, the SOC and State of Health (SOH) estimation by the Battery Management System (BMS) cannot be achieved. Therefore, when the lower limit of the SOC of the battery system falls above 20%, it is defined as the end-of-life (EOL) state of the battery. For example, the preset depth threshold can be defined as 80%.

[0110] For example, embodiments of this application can be applied to the two-way interaction (Vehicle-to-Grid, V2G) scenario between the energy storage function unique to electric vehicles and the power grid. By using the PID control principle to adjust the discharge cutoff SOC under V2G conditions, the target battery capacity retention rate can be achieved during the battery's lifespan.

[0111] The state-of-charge (SOC) adjustment method for a battery system provided in this application differs from existing technologies that use the SOC of low-capacity batteries (LFPs) to reflect the overall SOC of the battery system. This application first determines the target throughput range corresponding to the target cumulative throughput of the battery system. Then, based on the battery aging curve corresponding to the target throughput range, it adjusts the SOC of either the first or second battery system to ensure that the first and second battery systems maintain the same remaining capacity under the same cumulative throughput. The battery aging curve represents the mapping relationship between the remaining battery capacity and the cumulative throughput. This method not only improves the accuracy of the overall SOC assessment of the battery system but also ensures that the battery system maintains maximum capacity release without being affected by aging batteries, avoiding rapid degradation of the remaining battery capacity and further extending the battery system's lifespan. Simultaneously, it accurately defines the lifespan boundary of a battery system composed of two battery systems connected in series.

[0112] Based on the same inventive concept, this application also provides a battery system state-of-charge adjustment device corresponding to the battery system state-of-charge adjustment method. Since the principle of the device in this application is similar to the battery system state-of-charge adjustment method described above in this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0113] Please see Figure 3 , Figure 4 , Figure 3 This is a schematic diagram of the structure of a battery system state-of-charge regulation device provided in an embodiment of this application. Figure 4This is a schematic diagram of the structure of another battery system state-of-charge regulation device provided in an embodiment of this application. Figure 3 As shown, the device 300 includes:

[0114] Throughput acquisition module 301 is used to acquire the target cumulative throughput of the battery system during its service life.

[0115] The curve establishment module 302 is used to establish battery aging curves of the first system battery and the second system battery under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput.

[0116] The curve segmentation module 303 is used to determine multiple target throughput segmentation intervals and the battery aging curve corresponding to each target throughput segmentation interval based on the battery aging curves of the first system battery and the second system battery under different states of charge.

[0117] The state adjustment module 304 is used to determine the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjust the state of charge of the first system battery or the second system battery according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

[0118] In one optional embodiment of this application, the throughput acquisition module 301 is specifically used for:

[0119] Obtain the standard driving conditions during the lifespan of new energy vehicles to obtain the correlation between battery power and time in the battery system;

[0120] Based on the battery power and time of the battery system, calculate the target cumulative throughput of the battery system during its service life.

[0121] In one optional embodiment of this application, the curve establishment module 302 is specifically used for:

[0122] A first aging curve for the first system battery under a first state of charge, a second aging curve for the first system battery under a second state of charge, and a third aging curve for the second system battery under a second state of charge are established respectively; wherein, the aging rate of the first system battery is greater than the aging rate of the second system battery, and the depth of discharge corresponding to the first state of charge is less than the depth of discharge corresponding to the second state of charge.

[0123] In an optional embodiment of this application, the curve establishment module 302 is further configured to determine the first state of charge through the following steps:

[0124] Determine the first initial capacity of the first battery system and the second initial capacity of the second battery system; wherein the first initial capacity is greater than the second initial capacity;

[0125] The depth of discharge of the first battery system is determined based on the ratio between the second initial capacity and the first initial capacity, so as to determine the first state of charge based on the depth of discharge.

[0126] In one optional embodiment of this application, the curve segmentation module 303 is specifically used for:

[0127] The first throughput segment boundary value is determined based on the second aging curve of the first system battery under the second state of charge and the third aging curve of the second system battery under the second state of charge.

[0128] Based on the first aging curve of the first system battery under the first state of charge and the second aging curve of the first system battery under the second state of charge, the second throughput segment boundary value is determined; wherein, the first throughput segment boundary value is less than the second throughput segment boundary value.

[0129] Based on the determined first and second throughput segment boundary values, the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are obtained.

[0130] The battery aging curves corresponding to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are determined respectively; wherein, the battery aging curve corresponding to each target throughput segment interval includes a portion of the first aging curve, a portion of the second aging curve, and a portion of the third aging curve.

[0131] In one optional embodiment of this application, the state adjustment module 304 is specifically used for:

[0132] When the target cumulative throughput is not greater than the first throughput segment boundary value, the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

[0133] In one optional embodiment of this application, the state adjustment module 304 is further configured to:

[0134] When the target cumulative throughput is greater than the first throughput segment boundary value and not greater than the second throughput segment boundary value, if the actual throughput of the battery system during its service life is less than the first throughput segment boundary value, then the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

[0135] Alternatively, if the actual throughput is equal to the first throughput segment boundary value, then the state of charge of the control battery system remains unchanged.

[0136] Alternatively, if the actual throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, then the state of charge of the second system battery is adjusted according to the second aging curve of the first system battery under the second state of charge.

[0137] In one optional embodiment of this application, the state adjustment module 304 is further configured to:

[0138] When the target cumulative throughput is greater than the second throughput segment boundary value, the state of charge of the second system battery is adjusted according to the first aging curve of the first system battery under the first state of charge.

[0139] In an optional embodiment of this application, the device 300 further includes a lifetime detection module 305, which is used for:

[0140] If the remaining battery capacity of the battery system is detected to be no greater than a preset remaining capacity threshold, then the battery system is determined to have reached the end of its lifespan; wherein, the preset remaining capacity threshold is determined based on a preset weight and the second initial capacity of the second battery system.

[0141] Alternatively, if the depth of discharge corresponding to the adjusted state of charge of the second battery system is not greater than a preset depth threshold, then the battery system is determined to have reached the end of its lifespan.

[0142] The state-of-charge (SOC) adjustment device for a battery system provided in this application, compared with the prior art that uses the SOC of the battery pack (LFP) to reflect the overall SOC of the battery system, first determines the target throughput range corresponding to the target cumulative throughput of the battery system. Then, based on the battery aging curve corresponding to the target throughput range, it adjusts the SOC of the first or second battery pack to ensure that the first and second battery packs in the battery system maintain the same remaining capacity under the same cumulative throughput. The battery aging curve represents the mapping relationship between the remaining battery capacity and the cumulative throughput. This method not only improves the accuracy of the overall SOC assessment of the battery system but also ensures that the battery system maintains maximum capacity release without being affected by aging batteries, avoiding rapid degradation of the remaining battery capacity and further improving the battery system's lifespan. Simultaneously, it accurately defines the lifespan boundary of the battery system composed of two battery packs connected in series.

[0143] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5As shown, the electronic device 500 includes a processor 510, a memory 520, and a bus 530.

[0144] The memory 520 stores machine-readable instructions executable by the processor 510. When the electronic device 500 is running, the processor 510 and the memory 520 communicate via the bus 530. When the machine-readable instructions are executed by the processor 510, they can perform the operations described above. Figure 1 The steps of the battery system state-of-charge adjustment method in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0145] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The steps of the battery system state-of-charge adjustment method in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0146] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0147] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0148] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0149] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0150] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0151] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of state-of-charge adjustment of a battery system, characterized by, The battery system includes a first battery cell and a second battery cell connected in series, and the method includes: Obtain the target cumulative throughput of the battery system over its lifespan; Establish battery aging curves for the first and second battery systems under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput. Based on the battery aging curves of the first system battery and the second system battery under different states of charge, multiple target throughput segment intervals and the corresponding battery aging curves for each target throughput segment interval are determined. The target throughput range corresponding to the target cumulative throughput is determined from the throughput ranges corresponding to multiple battery aging curves, and the state of charge of the first system battery or the second system battery is adjusted according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

2. The method of claim 1, wherein, The steps for obtaining the target cumulative throughput of the battery system over its lifespan include: Obtain the standard driving conditions during the lifespan of new energy vehicles to obtain the correlation between battery power and time in the battery system; Based on the battery power and time of the battery system, calculate the target cumulative throughput of the battery system during its service life.

3. The method of claim 1, wherein, The steps for establishing battery aging curves for the first and second battery systems under different states of charge include: A first aging curve for the first system battery under a first state of charge, a second aging curve for the first system battery under a second state of charge, and a third aging curve for the second system battery under a second state of charge are established respectively; wherein, the aging rate of the first system battery is greater than the aging rate of the second system battery, and the depth of discharge corresponding to the first state of charge is less than the depth of discharge corresponding to the second state of charge.

4. The method according to claim 3, characterized in that, The first state of charge is determined by the following steps: Determine the first initial capacity of the first battery system and the second initial capacity of the second battery system; wherein the first initial capacity is greater than the second initial capacity; The depth of discharge of the first battery system is determined based on the ratio between the second initial capacity and the first initial capacity, so as to determine the first state of charge based on the depth of discharge.

5. The method according to claim 3, characterized in that, The steps for determining multiple target throughput segments and the corresponding battery aging curves for each target throughput segment based on the battery aging curves of the first and second battery systems under different states of charge include: The first throughput segment boundary value is determined based on the second aging curve of the first system battery under the second state of charge and the third aging curve of the second system battery under the second state of charge. Based on the first aging curve of the first system battery under the first state of charge and the second aging curve of the first system battery under the second state of charge, the second throughput segment boundary value is determined; wherein, the first throughput segment boundary value is less than the second throughput segment boundary value. Based on the determined first and second throughput segment boundary values, the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are obtained. The battery aging curves corresponding to the first throughput segment interval, the second throughput segment interval, and the third throughput segment interval are determined respectively; wherein, the battery aging curve corresponding to each target throughput segment interval includes a portion of the first aging curve, a portion of the second aging curve, and a portion of the third aging curve.

6. The method according to claim 5, characterized in that, The steps of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, include: When the target cumulative throughput is not greater than the first throughput segment boundary value, the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge.

7. The method according to claim 6, characterized in that, The steps of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, include: When the target cumulative throughput is greater than the first throughput segment boundary value and not greater than the second throughput segment boundary value, if the actual throughput of the battery system during its service life is less than the first throughput segment boundary value, then the state of charge of the first system battery is adjusted according to the third aging curve of the second system battery under the second state of charge. Alternatively, if the actual throughput is equal to the first throughput segment boundary value, then the state of charge of the control battery system remains unchanged. Alternatively, if the actual throughput is greater than the first throughput segment boundary value but not greater than the second throughput segment boundary value, then the state of charge of the second system battery is adjusted according to the second aging curve of the first system battery under the second state of charge.

8. The method according to claim 7, characterized in that, The steps of determining the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjusting the state of charge of the first battery system or the second battery system according to the battery aging curve corresponding to the target throughput range, include: When the target cumulative throughput is greater than the second throughput segment boundary value, the state of charge of the second system battery is adjusted according to the first aging curve of the first system battery under the first state of charge.

9. The method according to claim 8, characterized in that, The method further includes: If the remaining battery capacity of the battery system is detected to be no greater than a preset remaining capacity threshold, then the battery system is determined to have reached the end of its lifespan; wherein, the preset remaining capacity threshold is determined based on a preset weight and the second initial capacity of the second battery system. Alternatively, if the depth of discharge corresponding to the adjusted state of charge of the second battery system is not greater than a preset depth threshold, then the battery system is determined to have reached the end of its lifespan.

10. A state-of-charge (SOC) regulation device for a battery system, characterized in that, The battery system includes a first battery cell and a second battery cell connected in series, and the device includes: Throughput acquisition module is used to acquire the target cumulative throughput of the battery system during its service life; The curve establishment module is used to establish battery aging curves for the first system battery and the second system battery under different states of charge. The battery aging curves are used to represent the mapping relationship between the remaining battery capacity and the cumulative throughput. The curve segmentation module is used to determine multiple target throughput segment intervals and the corresponding battery aging curves for each target throughput segment interval based on the battery aging curves of the first system battery and the second system battery under different states of charge. The state adjustment module is used to determine the target throughput range corresponding to the target cumulative throughput from the throughput ranges corresponding to multiple battery aging curves, and adjust the state of charge of the first system battery or the second system battery according to the battery aging curve corresponding to the target throughput range, so that the first system battery and the second system battery in the battery system maintain the same remaining battery capacity under the same cumulative throughput.

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