Battery charging control method, battery management device and automobile

Abstract

This invention provides a battery charging control method, a battery management device, and an automobile. The battery charging control method acquires the current cycle count of the battery and, based on the relationship between the current cycle count, multiple preset cycle ranges, and a preset charging voltage, determines the upper limit of the charging voltage corresponding to the current cycle count. This allows the battery to have different states of charge (SOCs) for different preset cycle ranges, ensuring a higher SOC at higher cycle counts. This guarantees that the battery's positive electrode maintains a similar capacity across different preset cycle ranges, thus preventing significant degradation of battery health throughout its lifespan and addressing the technical problem of significantly reduced battery power utilization. The battery management device includes a processor configured to execute instructions to implement the battery charging control method; the automobile includes a battery management device.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a battery charging control method, a battery pack charging control method, a battery management device, and an automobile. Background Technology

[0002] Lithium-ion batteries are mostly constructed using ternary materials combined with graphite systems or lithium iron phosphate materials combined with graphite systems. Their cycle life is typically 3000-5000 cycles, with long-life batteries reaching around 10000 cycles. During the battery's lifespan, its State of Health (SOH) significantly degrades, leading to a substantial reduction in its power output. Summary of the Invention

[0003] Embodiments of the present invention provide a battery charging control method, a battery management device, and an automobile, which can improve the technical problem that the battery health status significantly degrades during the battery's lifespan, resulting in a significant reduction in the battery's power utilization capability.

[0004] In a first aspect, embodiments of the present invention provide a battery charging control method, comprising: acquiring the current cycle number of a battery; and determining an upper limit of the charging voltage corresponding to the current cycle number of the battery based on the current cycle number, a plurality of preset cycle ranges and a preset charging voltage.

[0005] Optionally, in some embodiments of the present invention, the step of determining the upper limit of the charging voltage corresponding to the current cycle number of the battery based on the relationship between the current cycle number, multiple preset cycle ranges and preset charging voltage includes: determining the preset cycle range in which the current cycle number is located, and determining the preset charging voltage corresponding to the preset cycle range in which the current cycle number is located, based on the preset cycle range in which the current cycle number is located, as the upper limit of the charging voltage corresponding to the current cycle number of the battery.

[0006] Optionally, in some embodiments of the present invention, the plurality of preset cycle ranges include at least a first preset cycle range and a second preset cycle range. The first preset cycle range has a first endpoint value and a second endpoint value greater than the first endpoint value, and the second preset cycle range has a third endpoint value and a fourth endpoint value greater than the third endpoint value. The third endpoint value is greater than the second endpoint value; and the second preset charging voltage corresponding to the second preset cycle range is greater than the first preset charging voltage corresponding to the first preset cycle range.

[0007] Optionally, in some embodiments of the present invention, the step of determining the preset cycle range in which the current cycle number falls, and determining the preset charging voltage corresponding to the preset cycle range in which the current cycle number falls, as the upper limit of the charging voltage corresponding to the current cycle number for the battery, includes: determining whether the current cycle number is within the first preset cycle range; when the current cycle number is within the first preset cycle range, determining the first preset charging voltage as the upper limit of the charging voltage corresponding to the current cycle number for the battery; when the current cycle number is not within the first preset cycle range, determining whether the current cycle number is within the second preset cycle range; when the current cycle number is within the second preset cycle range, determining the second preset charging voltage as the upper limit of the charging voltage corresponding to the current cycle number for the battery.

[0008] Optionally, in some embodiments of the present invention, the difference between the second endpoint value and the first endpoint value is less than a preset number of cycles, and the difference between the fourth endpoint value and the third endpoint value is less than the preset number of cycles. The preset number of cycles is equal to the number of cycles corresponding to a 5% degradation in the battery's health state.

[0009] Optionally, in some embodiments of the present invention, the CB value of the battery is greater than or equal to a first preset value and less than or equal to a second preset value. The first preset value is equal to 1.05 times the preset state of charge of the battery corresponding to the first preset cycle range, and the second preset value is equal to 1.2 times the preset state of charge.

[0010] Optionally, in some embodiments of the present invention, the plurality of preset charging voltages corresponding to the plurality of preset cycle ranges are obtained based on the correspondence between the state of charge and open circuit voltage of the battery.

[0011] Optionally, in some embodiments of the present invention, the plurality of preset cycle ranges correspond to the plurality of preset charging voltages, and the maximum value among the plurality of preset charging voltages is equal to the maximum charging voltage of the battery.

[0012] Secondly, embodiments of the present invention also provide a battery management device, including a processor and a memory. The processor is configured to execute instructions to implement any of the above-described battery charging control methods; the memory is used to store the instructions of the processor.

[0013] Thirdly, embodiments of the present invention also provide an automobile including any of the battery management devices described above.

[0014] The beneficial effects of the embodiments of the present invention are as follows:

[0015] In embodiments of the present invention, by obtaining the current cycle count of the battery and determining the upper limit of the charging voltage corresponding to the current cycle count based on the relationship between the current cycle count, multiple preset cycle ranges, and preset charging voltage, the battery can have different states of charge for different preset cycle ranges. This ensures that the state of charge is also larger when the cycle count is larger, thereby ensuring that the positive electrode of the battery can perform similar capacity in different preset cycle ranges. This ensures that the battery health does not significantly degrade throughout its lifespan, thus improving the technical problem of a significant decrease in battery power utilization. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figures 1A-1B This is a flowchart of a battery charging control method provided in an embodiment of the present invention;

[0018] Figure 2 This is a curve showing the change in battery health status with the number of cycles provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the battery management device provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only 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 present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In the present invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0021] Figures 1A-1B This is a flowchart of a battery charging control method provided in an embodiment of the present invention; an embodiment of the present invention provides a battery charging control method, including:

[0022] Get the current cycle count of the battery;

[0023] Based on the relationship between the current number of cycles, multiple preset cycle ranges, and preset charging voltage, the upper limit of the charging voltage corresponding to the current number of cycles for the battery is determined.

[0024] Since the upper limit of the charging voltage corresponding to the current cycle number is determined based on the relationship between the current cycle number, multiple preset cycle ranges, and preset charging voltage, the battery can have different maximum states of charge for different preset cycle ranges. This ensures that the state of charge is also larger when the number of cycles is large, thereby ensuring that the positive electrode of the battery can perform with similar capacity in different preset cycle ranges. This ensures that the battery health does not significantly degrade throughout its lifespan and improves the technical problem of significant decline in battery power utilization.

[0025] Optionally, the battery can be a single cell, a battery module comprising multiple individual cells, or a battery pack comprising multiple individual cells. That is, the battery charging control method is applicable to a single individual cell, a battery module, or a battery pack.

[0026] Optionally, the battery includes a ternary material combined with a graphite system.

[0027] Optionally, the battery may be a positive electrode NCM622 + negative electrode high-power artificial graphite + PE membrane system + LiPF6 electrolyte system, and the battery capacity is designed as a power type square aluminum shell 20Ah.

[0028] Optionally, the positive electrode of the battery includes lithium manganese oxide, lithium cobalt oxide, lithium iron phosphate, etc., the negative electrode of the battery includes natural graphite, etc., and the intermediate components of the battery include carbon microspheres, soft carbon, hard carbon, silicon carbon materials, etc.

[0029] It should be noted that the number of battery cycles refers to the number of times the battery completes one full charge-discharge cycle. The number of battery cycles can be calculated by accumulating the battery's discharge capacity.

[0030] Optionally, the current cycle number of the battery can be obtained by recording the cycle number of the battery through a battery management device.

[0031] Optionally, the relationship between the preset cycle ranges and the preset charging voltage can be preset and stored in a memory.

[0032] Optionally, the relationship between the multiple preset cycle ranges and the preset charging voltage can be determined by taking into account factors such as the required lifespan of the battery, the electrochemical performance of the battery, and the complexity of software updates.

[0033] Assuming the required lifespan of the battery is equal to a first preset value; during actual use, if the change in the battery's state of health is less than a second preset value, the battery's electrochemical performance remains relatively stable, and its energy and power output do not change significantly. However, if the change in the battery's state of health is greater than or equal to the second preset value, the battery's electrochemical performance changes significantly, and its energy and power output change considerably. Therefore, the charge state of the battery corresponding to a first preset cycle range among multiple preset cycle ranges can be determined based on the first preset value. The interval length of the preset cycle range can be determined based on the second preset value and the software update complexity. Multiple preset voltages corresponding to the multiple preset cycle ranges can be obtained based on the first preset value, the second preset value, and the correspondence between the battery's state of charge and open-circuit voltage. Here, the first preset value is characterized by the battery's state of charge.

[0034] Specifically, assuming the required lifespan of the battery is equal to 80% of the state of charge (i.e., the first set value is equal to 80%), when the battery health status changes by less than 5% during actual use (i.e., the second set value is equal to 5%), the electrochemical performance of the battery can remain relatively stable, and the energy and power output of the battery will not change significantly. Therefore, the maximum state of charge (SOC) of the battery corresponding to the first preset cycle range among the multiple preset cycle ranges can be set to 80%. The interval length of the preset cycle range can be less than the number of cycles corresponding to the battery when the battery's health state degrades by 5% (e.g., if the number of cycles corresponding to the battery when the battery's health state degrades by 5% is 15,000, then the interval length of the preset cycle range can be less than 15,000). However, considering that the more preset cycle ranges are set, the more upper limits of the charging voltage of the battery will be, and frequent adjustments to the upper limit of the charging voltage will increase the complexity of software updates, the interval length of the preset cycle range can be set to 5,000, 8,000, 10,000, 12,000, 14,000, etc., to balance the complexity of software updates and battery performance. The multiple preset voltages corresponding to the multiple preset cycle ranges can be obtained based on the correspondence between the battery's state of charge and open-circuit voltage; that is, starting from 80% battery state of charge, a preset voltage is obtained for every 5% increase in the battery's state of charge, until the battery's state of charge increases to 100%, resulting in multiple preset voltages corresponding to the multiple preset cycle ranges. The voltage value corresponding to the battery's state of charge of 80% can be used as the upper limit of the charging voltage for the first preset cycle range among the multiple preset cycle ranges.

[0035] The larger the first setting value is, the fewer the number of preset cycle ranges can be set, the larger the cycle interval of the battery corresponding to each preset cycle range will be, and the shorter the battery life will be. Therefore, to ensure that the battery has a long life, the first setting value can be set to 50% to 95%.

[0036] It is understood that the required lifespan of the battery (i.e., the first set value) can be set according to the actual user's usage needs, and the second set value can be determined according to the actual battery parameters used.

[0037] Optionally, the step of determining the upper limit of the charging voltage corresponding to the current cycle number of the battery based on the relationship between the current cycle number, multiple preset cycle ranges, and preset charging voltage includes:

[0038] Determine the preset cycle range in which the current cycle number is located, and determine the preset charging voltage corresponding to the preset cycle range in which the current cycle number is located, so as to serve as the upper limit of the charging voltage of the battery corresponding to the current cycle number.

[0039] That is, the plurality of preset cycle ranges may include at least a first preset cycle range and a second preset cycle range. By determining whether the current cycle number is within the first preset cycle range or the second preset cycle range, it is determined whether the first preset charging voltage corresponding to the first preset cycle range is the upper limit of the charging voltage of the battery corresponding to the current cycle number, or whether the second preset charging voltage corresponding to the second preset cycle range is the upper limit of the charging voltage of the battery corresponding to the current cycle number.

[0040] Alternatively, please continue reading Figure 1B The step of determining the preset cycle range in which the current cycle number falls, and determining the preset charging voltage corresponding to the preset cycle range in which the current cycle number falls, as the upper limit of the charging voltage of the battery corresponding to the current cycle number, includes:

[0041] Determine whether the current loop count is within the first preset loop range;

[0042] When the current number of cycles is within the first preset cycle range, the first preset charging voltage is determined as the upper limit of the charging voltage corresponding to the current number of cycles for the battery;

[0043] When the current number of iterations is not within the first preset iteration range, determine whether the current number of iterations is within the second preset iteration range;

[0044] When the current cycle number is within the second preset cycle range, the second preset charging voltage is determined as the upper limit of the charging voltage corresponding to the current cycle number of the battery.

[0045] Optionally, the first preset cycle range has a first endpoint value and a second endpoint value greater than the first endpoint value, and the second preset cycle range has a third endpoint value and a fourth endpoint value greater than the third endpoint value. The third endpoint value is greater than the second endpoint value; the second preset charging voltage corresponding to the second preset cycle range is greater than the first preset charging voltage corresponding to the first preset cycle range. For example, if the interval range corresponding to the first preset cycle range is [0~10000) and the interval range corresponding to the second preset cycle range is [10000~20000), then the first endpoint value is 0, the second endpoint value is 9999, the third endpoint value is 10000, and the fourth endpoint value is 19999.

[0046] Optionally, the difference between the second endpoint value and the first endpoint value is less than a preset number of cycles, and the difference between the fourth endpoint value and the third endpoint value is less than the preset number of cycles. The preset number of cycles is equal to the number of cycles corresponding to a 5% degradation in the battery's health state. For example, if the number of cycles corresponding to a 5% degradation in the battery's health state is 15,000, and the preset number of cycles is 15,000, then the interval length corresponding to both the first and second preset cycle ranges is less than 15,000.

[0047] Optionally, the plurality of preset cycle ranges further include a third preset cycle range, a fourth preset cycle range, and a fifth preset cycle range. Optionally, the third preset cycle range has a fifth endpoint value and a sixth endpoint value greater than the fifth endpoint value; the fourth preset cycle range has a seventh endpoint value and an eighth endpoint value greater than the seventh endpoint value; and the fifth preset cycle range has a ninth endpoint value and a tenth endpoint value greater than the ninth endpoint value. Wherein, the seventh endpoint value is greater than the sixth endpoint value, and the ninth endpoint value is greater than the eighth endpoint value; the third preset charging voltage corresponding to the third preset cycle range is greater than the second preset charging voltage corresponding to the second preset cycle range; the fourth preset charging voltage corresponding to the fourth preset cycle range is greater than the third preset charging voltage; and the fifth preset charging voltage corresponding to the fifth preset cycle range is greater than the fourth preset charging voltage. That is, the preset charging voltage corresponding to the preset cycle range with a smaller number of cycles is less than the preset charging voltage corresponding to the preset cycle range with a larger number of cycles.

[0048] Accordingly, after the step of determining whether the current loop count is within the second preset loop range when the current loop count is not within the first preset loop range, the method further includes:

[0049] When the current number of iterations is not within the second preset iteration range, it is determined whether the current number of iterations is within the third preset iteration range;

[0050] When the current number of cycles is within the third preset cycle range, a third preset charging voltage corresponding to the third preset cycle range is determined as the upper limit of the charging voltage of the battery corresponding to the current number of cycles;

[0051] When the current number of cycles is not within the third preset cycle range, it is determined whether the current number of cycles is within the fourth preset cycle range;

[0052] When the current number of cycles is within the fourth preset cycle range, a fourth preset charging voltage corresponding to the fourth preset cycle range is determined as the upper limit of the charging voltage of the battery corresponding to the current number of cycles;

[0053] When the current number of cycles is not within the fourth preset cycle range, it is determined whether the current number of cycles is within the fifth preset cycle range;

[0054] When the current cycle number is within the fifth preset cycle range, a fifth preset charging voltage corresponding to the fifth preset cycle range is determined as the upper limit of the charging voltage of the battery corresponding to the current cycle number.

[0055] It is understood that the number of the preset loop ranges is not limited to five (i.e., the number of preset loop ranges may be greater than or equal to two).

[0056] The number of preset cycle ranges can be determined based on the required lifespan of the battery (i.e., the first set value) and the relationship between the battery health status and electrochemical performance (such as the second set value).

[0057] Taking an example where the first preset value equals 80% and the second preset value equals 5%, the multiple preset cycle ranges include the first preset cycle range, the second preset cycle range, the third preset cycle range, the fourth preset cycle range, and the fifth preset cycle range. Specifically, the maximum state of charge (SOC) of the battery corresponding to the first preset cycle range can be 80%, the maximum SOC of the battery corresponding to the second preset cycle range can be 85%, the maximum SOC of the battery corresponding to the third preset cycle range can be 90%, the maximum SOC of the battery corresponding to the fourth preset cycle range can be 95%, and the maximum SOC of the battery corresponding to the fifth preset cycle range can be 100%.

[0058] Optionally, the interval lengths corresponding to the first preset cycle range, the second preset cycle range, the third preset cycle range, the fourth preset cycle range, and the fifth preset cycle range can be the same or different to meet different design requirements.

[0059] Taking a battery with a positive electrode of NCM622, a negative electrode of high-power artificial graphite, a PE membrane, and a LiPF6 electrolyte system, and a capacity designed as a 20Ah power-type square aluminum shell as an example, the battery's cycle life is 15,000 when its health condition degrades by 5%. In actual testing, the selected interval length of the preset cycle range is 10,000.

[0060] The correspondence between the state of charge and open-circuit voltage of the battery is shown in Table 1:

[0061]

[0062] Therefore, the relationship between the multiple preset cycle ranges and the preset charging voltage can be set as shown in Table 2:

[0063]

[0064] Cycling at 2C / 2C rate (i.e., ambient temperature 40 degrees Celsius, 2C charging to 3.95V, resting for 30 minutes, 2C discharging to 2.8V, resting for 30 minutes), a mid-cycle test is performed every 10,000 cycles. The upper limit of the charging voltage is adjusted according to Table 2 to proceed to the next preset cycle range, thereby obtaining... Figure 2 The curves showing the change in battery health status with the number of cycle times are shown. Figure 2 The figure shows the curves of battery health status as a function of the number of cycles for each of the 23 tested batteries.

[0065] That is, when the current cycle count is within the range [0-10000] corresponding to the first preset cycle range, the positive electrode of the battery utilizes 80% of its capacity. At this time, if the CB value of the battery is 0.85, the negative electrode has approximately 85% vacancy to receive active lithium released from the positive electrode. When the current cycle count is greater than the range corresponding to the first preset cycle range and the capacity of the positive electrode of the battery decreases by approximately 5%, the upper limit of the charging voltage of the battery is increased, so that when the current cycle count is within the range [10000-20000] corresponding to the second preset cycle range, the positive electrode of the battery can again utilize 80% of its capacity. This continues until the current cycle count is within the range [40000-50000] corresponding to the fifth preset cycle range, at which point the positive electrode of the battery can still utilize 80% of its capacity. Therefore, throughout the battery's lifespan, the state of charge of the battery increases, but the actual capacity utilized by the battery remains unchanged, so that the battery's health does not significantly decline (e.g., ...). Figure 2 (as shown), thus simplifying the algorithm complexity for calculating the battery's output power capability.

[0066] Understandably, the lower limit of the charging voltage for the battery can vary depending on the battery type. For example, the lower limit of the charging voltage for NCM material systems can be 2.8V, for lithium iron phosphate systems it can be 2.5V, for lithium cobalt oxide systems it can be 3.2V, and for lithium manganese oxide systems it can be 2.8V. In practical applications, the lower limit of the charging voltage can be set according to the user's usage scenario. For example, in common hybrid battery designs, the lower limit of the charging voltage can be set to the voltage value corresponding to a state of charge of 30% (e.g., around 3.6V).

[0067] Understandably, when the battery is a battery pack comprising multiple individual cells, multiple preset charging voltages corresponding to the battery pack can be determined by the charging voltage corresponding to each individual cell and the number of battery modules included in the battery pack. For example, if the battery pack includes 12 battery modules and the charging voltage corresponding to each battery module is 2.8V to 4.2V, then the charging voltage of the battery pack is 2.8*12V to 4.2*12V. Accordingly, if the upper limit of the charging voltage for the first preset cycle range (e.g., the range is [0~10000)) corresponding to the battery module is 3.95V, then the upper limit of the charging voltage for the first preset cycle range (the range is [0~10000)) corresponding to the battery pack comprising 12 battery modules is 3.95*12V. Similarly, the upper limits of the charging voltage corresponding to the battery pack and other preset cycle ranges can be obtained.

[0068] Optionally, the plurality of preset cycle ranges correspond to the plurality of preset charging voltages, and the maximum value among the plurality of preset charging voltages is equal to the maximum charging voltage of the battery, so as to avoid the battery being charged with a voltage exceeding its capacity, thereby affecting the performance of the battery.

[0069] Optionally, the CB value of the battery is greater than or equal to a first preset value and less than or equal to a second preset value. The first preset value is equal to 1.05 times the preset state of charge (SOC) of the battery within the first preset cycle range, and the second preset value is equal to 1.2 times the SOC. This design, which matches the CB value of the entire battery with the charging voltage, aims to achieve an ultra-long cycle life (>50,000 cycles).

[0070] Furthermore, by setting the CB value to be greater than or equal to the first preset value and less than or equal to the second preset value, the positive electrode capacity can be set to a lower value, and correspondingly, the negative electrode capacity will also be lower. Since the negative electrode capacity is low, less material is required for the negative electrode, thereby saving the material used in the battery negative electrode.

[0071] If we assume that the preset state of charge corresponding to the first preset cycle range is 80%, then the first preset value is equal to 80% * 1.05, and the second preset value is equal to 80% * 1.2. Accordingly, the CB value of the battery is greater than or equal to 80% * 1.05 and less than or equal to 80% * 1.2.

[0072] Optionally, the CB value of the battery may be equal to 80%*1.05, 80%*1.1, 80%*1.15 or 80%*1.2.

[0073] Optionally, if the positive electrode capacity of the battery is maintained at 75-80% of the design capacity during its lifespan, then, considering the errors during actual use, the negative electrode of the battery has a redundancy of about 5%, and correspondingly, the CB value of the battery can be set to 0.85.

[0074] Optionally, the preset state of charge is equal to the first set value. Optionally, the preset state of charge is equal to the maximum value of the battery's state of charge corresponding to the first preset cycle range.

[0075] The battery charging control method provided by the present invention can maintain the battery's healthy state without degradation throughout its lifespan as the battery's operating voltage platform gradually increases, thereby preventing significant degradation in power capability and greatly simplifying the algorithm complexity for calculating the output power capability of the battery pack.

[0076] like Figure 3 This is a schematic diagram of the structure of a battery management device provided in an embodiment of the present invention. An embodiment of the present invention also provides a battery management device, including a processor and a memory. The processor is configured to execute instructions to implement any of the above-described battery charging control methods; the memory is used to store the instructions of the processor.

[0077] Optionally, embodiments of the present invention also provide an automobile including any of the battery management devices described above.

[0078] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A battery charging control method, characterized in that, include: Get the current cycle count of the battery; Based on the relationship between the current number of cycles, multiple preset cycle ranges, and preset charging voltage, determine the upper limit of the charging voltage corresponding to the current number of cycles for the battery; The plurality of preset cycle ranges include a first preset cycle range, the first preset cycle range having a first endpoint value and a second endpoint value greater than the first endpoint value, the difference between the second endpoint value and the first endpoint value being less than a preset cycle number, the preset cycle number being equal to the cycle number corresponding to when the battery health state of the battery decays by 5%; The CB value of the battery is greater than or equal to a first preset value and less than or equal to a second preset value; The first preset value is equal to 1.05 times the preset state of charge of the battery in the first preset cycle range, and the second preset value is equal to 1.2 times the preset state of charge.

2. The battery charging control method according to claim 1, characterized in that, The step of determining the upper limit of the charging voltage corresponding to the current cycle number of the battery based on the relationship between the current cycle number, multiple preset cycle ranges, and preset charging voltage includes: Determine the preset cycle range in which the current cycle number is located, and determine the preset charging voltage corresponding to the preset cycle range in which the current cycle number is located, so as to serve as the upper limit of the charging voltage of the battery corresponding to the current cycle number.

3. The battery charging control method according to claim 2, characterized in that, The plurality of preset cycle ranges also include: A second preset cycle range, wherein the second preset cycle range has a third endpoint value and a fourth endpoint value greater than the third endpoint value; Wherein, the third endpoint value is greater than the second endpoint value; and the second preset charging voltage corresponding to the second preset cycle range is greater than the first preset charging voltage corresponding to the first preset cycle range.

4. The battery charging control method according to claim 3, characterized in that, The step of determining the preset cycle range in which the current cycle number falls, and determining the preset charging voltage corresponding to the preset cycle range in which the current cycle number falls, as the upper limit of the charging voltage of the battery corresponding to the current cycle number, includes: Determine whether the current loop count is within the first preset loop range; When the current number of cycles is within the first preset cycle range, the first preset charging voltage is determined as the upper limit of the charging voltage corresponding to the current number of cycles for the battery; When the current number of iterations is not within the first preset iteration range, determine whether the current number of iterations is within the second preset iteration range; When the current cycle number is within the second preset cycle range, the second preset charging voltage is determined as the upper limit of the charging voltage corresponding to the current cycle number of the battery.

5. The battery charging control method according to claim 3, characterized in that, The difference between the fourth endpoint value and the third endpoint value is less than the preset number of cycles.

6. The battery charging control method according to any one of claims 1 to 5, characterized in that, The multiple preset charging voltages corresponding to the multiple preset cycle ranges are obtained based on the correspondence between the state of charge and open circuit voltage of the battery.

7. The battery charging control method according to any one of claims 1 to 5, characterized in that, The multiple preset cycle ranges correspond to multiple preset charging voltages, and the maximum value among the multiple preset charging voltages is equal to the maximum charging voltage of the battery.

8. A battery management device, characterized in that, include: The processor is configured to execute instructions to implement the battery charging control method according to any one of claims 1 to 7; A memory for storing the instructions of the processor.

9. A car, characterized in that, Includes the battery management device as described in claim 8.

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