WO2022252015A1 - 确定电池的荷电状态的方法、电池管理***及用电装置 - Google Patents

确定电池的荷电状态的方法、电池管理***及用电装置 Download PDF

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WO2022252015A1
WO2022252015A1 PCT/CN2021/097255 CN2021097255W WO2022252015A1 WO 2022252015 A1 WO2022252015 A1 WO 2022252015A1 CN 2021097255 W CN2021097255 W CN 2021097255W WO 2022252015 A1 WO2022252015 A1 WO 2022252015A1
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battery
voltage
change rate
charge
voltage change
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PCT/CN2021/097255
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English (en)
French (fr)
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魏洪贵
杜明树
谢延敏
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2021/097255 priority Critical patent/WO2022252015A1/zh
Priority to HUE21908120A priority patent/HUE063084T2/hu
Priority to CN202180006352.6A priority patent/CN115699400A/zh
Priority to EP21908120.5A priority patent/EP4123783B1/en
Priority to US17/847,188 priority patent/US11693059B2/en
Publication of WO2022252015A1 publication Critical patent/WO2022252015A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/385—Arrangements for measuring battery or accumulator variables
    • G01R31/387—Determining ampere-hour charge capacity or SoC
    • G01R31/388—Determining ampere-hour charge capacity or SoC involving voltage measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/10—Measuring sum, difference or ratio
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/374—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] with means for correcting the measurement for temperature or ageing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3835—Arrangements for monitoring battery or accumulator variables, e.g. SoC involving only voltage measurements

Definitions

  • the present invention relates to the technical field of batteries, in particular to a method for determining the state of charge of a battery, a battery management system and an electrical device.
  • SOC state of charge
  • the main methods for estimating the SOC of the battery are the ampere-hour integration method and the open-circuit voltage method.
  • the ampere-hour integration method is affected by the measurement accuracy, sampling frequency and initial SOC error, resulting in a certain error in the calculation result, and the error will continue over time. Cumulatively, the SOC accuracy of the battery in long-term operation cannot be guaranteed.
  • the Open Circuit Voltage (OCV) method presents different voltage curves due to the charging voltage of the battery under the influence of factors such as different temperatures and magnifications, and the SOC corresponding to the same voltage value varies greatly, so the accuracy of the obtained SOC is low.
  • the purpose of the present invention is to provide a method for determining the state of charge of a battery, a battery management system (Battery Management System, BMS) and a vehicle, so as to improve the estimation accuracy of SOC.
  • BMS Battery Management System
  • the first aspect of the present invention provides a method for determining the state of charge of a battery, the method comprising:
  • the corrected state of charge of the battery is obtained as the actual state of charge of the battery.
  • the preset voltage threshold is 5mV.
  • Voltage change rate the preset voltage threshold/(tn-tj),
  • Vn-Vj is the voltage difference of the voltage difference Vn-Vi greater than or equal to the preset voltage threshold for the first time
  • tj is the sampling time for obtaining the voltage Vj.
  • the minimum voltage greater than or equal to the preset voltage threshold is obtained.
  • the voltage difference makes the calculated voltage change rate the highest accuracy, so that the actual state of charge of the battery can be corrected more accurately; on the other hand, it is not necessary to calculate all the voltage differences Vn-Vi, which reduces the amount of calculation.
  • the sampling time ti is the earliest sampling time for obtaining the state of charge of the battery within the preset time period before the sampling time tn.
  • ti is the earliest sampling time t1 among the n-1 sampling times, and only Vn-V1 is calculated each time, thereby reducing the calculation amount and the amount of intermediate data.
  • the voltage Vn, temperature Tn and charging rate Cn, and the voltage Vi of the battery at the sampling time ti and calculate the voltage difference Vn-Vi between the voltage Vn and the voltage Vi.
  • the charging high end is that the state of charge of the battery is above the preset state of charge threshold and the voltage change rate of the battery is above the preset voltage change rate threshold state, preferably, the preset state of charge threshold is 70%.
  • the preset state of charge threshold can be set to be suitable for the type of battery used and component thresholds.
  • step d) comprises:
  • the preset voltage change rate thresholds include k-level voltage change rate thresholds
  • the method includes:
  • the corrected charge of the battery is The corresponding relationship between the state of charge and the threshold value of the x-level voltage change rate, temperature, and charging rate, obtain the corrected state of charge of the battery as the actual state of charge of the battery, and set the position of the x-level correction flag 0;
  • x k, k-1,..., 3, 2, and k is greater than or equal to 3, and the voltage change rate threshold of the xth stage is greater than the voltage change rate threshold of the x-1th stage;
  • the battery When the voltage change rate is greater than or equal to the first level voltage change rate threshold and the first level correction flag is 1, according to the temperature Tn and charge rate Cn of the battery at the sampling time tn, the battery’s Correcting the corresponding relationship between the state of charge and the threshold value of the first-level voltage change rate, temperature, and charging rate, obtaining the corrected state of charge of the battery as the actual state of charge of the battery, and correcting the first-level flag position 0; and
  • the method comprises: filtering the voltage rate of change, and comparing in step d) the filtered voltage rate of change with the preset voltage rate of change threshold.
  • sampling error or noise error will bring about voltage fluctuation, the influence of voltage fluctuation caused by sampling error or noise error can be reduced by filtering.
  • the filtered rate of voltage change is calculated according to the following formula:
  • Filtered voltage change rate K1*(voltage change rate at sampling time tn)+K2*(voltage change rate at sampling time tm),
  • the sampling time tm is the latest sampling time at which the voltage change rate is calculated before the sampling time tn
  • the method comprises, prior to step b):
  • step a2) Detecting and judging whether the charging current is stable and whether the voltage of the battery at the sampling time tn is valid, if yes, proceed to the next step; if not, return to step a1).
  • the sampling value of the voltage may be wrong. Since the general concept of the present invention is based on the sampling voltage value, judging whether the current voltage is valid ensures the reliability of SOC correction. In some embodiments, it is judged whether the current voltage is valid according to whether the voltage of the battery at the sampling time tn exceeds a preset sampling range, that is, the voltage of the battery at the sampling time tn is within the preset It is not a valid voltage outside the sampling range. For example, the normal voltage range of a lithium iron phosphate battery is between 1.5V-4.5V. In one embodiment, it is judged whether the voltage is valid according to whether the voltage of the battery at the sampling time tn is between 500mV-6000mV , that is, voltages lower than 500mV or higher than 6000mV are not effective voltages.
  • a second aspect of the present invention provides a battery management system, which includes: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions, and when the instructions When executed by the at least one processor, the instructions cause the at least one processor to perform the method for correcting the charge of the battery as described in the first aspect of the present invention and any possible implementation of the first aspect. method of power state.
  • a third aspect of the present invention provides a device, the device comprising: a battery; and a battery management system according to the second aspect of the present invention.
  • the battery can be used as a power source for the device and also as an energy storage unit for the device.
  • the device can be, but not limited to, a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a battery according to its use requirements.
  • FIG. 1 illustrates a flowchart of a method for correcting the state of charge of a battery according to one embodiment of the present invention.
  • FIG. 2 illustrates a flow diagram of a portion of a method for correcting a state of charge of a battery according to an embodiment of the present invention.
  • Figure 3(a) and Figure 3(b) respectively illustrate schematic diagrams of the voltage-SOC curve and the voltage change rate-SOC curve of a lithium iron phosphate battery according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of multiple voltage-SOC curves of a battery at different temperatures and charge rates according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of multiple voltage change rate-SOC curves of a battery at different temperatures and charge rates according to an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of a battery management system according to an embodiment of the present invention.
  • Fig. 7 is a schematic diagram of an electrical device including a battery management system according to an embodiment of the present invention.
  • FIG. 1 illustrates a flowchart of a method for correcting the state of charge of a battery according to one embodiment of the present invention.
  • the method for correcting the state of charge of the battery in the present invention mainly corrects the SOC of the battery in the charging high-end region of the battery.
  • step 102 it is detected whether the battery is in the charging state according to the flow of the charging current, and if the battery is in the charging state, then go to step 104 , otherwise, repeat step 102 .
  • step 102 it is not only detected whether the battery is in a charging state, but also whether the charging current is stable and whether the current voltage of the battery is valid.
  • it is determined whether the charging current is in a constant current charging state by detecting whether the charging current fluctuates, that is, has a constant charging rate.
  • whether the current voltage is valid is determined according to whether the current voltage of the battery exceeds the preset sampling range, that is, the current voltage is not a valid voltage when it is outside the preset sampling range.
  • the normal voltage range of a lithium iron phosphate battery is between 2.5V-3.65V.
  • it is judged whether the voltage is valid according to whether the voltage of the battery at the sampling time tn is between 500mV-6000mV. , that is, voltages lower than 500mV or higher than 6000mV are not effective voltages.
  • the battery management system always obtains or calculates the SOC of the battery and collects data such as battery voltage, temperature and charge rate at a preset sampling period; assuming that the current sampling time is tn, the sampling time tn collects The received voltage is Vn, the temperature is Tn, the charging rate is Cn, and the sampling time before the current sampling time tn is tn-1.
  • the current sampling time tn is the latest sampling time
  • the sampling time tn-1 is the second closest sampling time.
  • step 104 the SOC of the battery at the current sampling time tn is acquired; then, in step 106, it is detected whether the battery is in the charging high-end region. In some embodiments, it is judged whether the battery is in the high-end region of charge by judging whether the state of charge of the battery is greater than a preset state-of-charge threshold; if the battery is in the high-end region of charge, proceed to step 108, otherwise repeat step 104.
  • the voltage change rate-SOC curve of the lithium iron phosphate battery has an obvious protrusion at about 20% SOC and 60% SOC, and the embodiment of the present invention is not suitable for this voltage change rate fluctuations.
  • the state of charge threshold can be set to 70% to avoid the fluctuation of the voltage change rate in Figure 3(b)
  • Figure 3(a) shows the theoretical range of the high-end region of charge, where the SOC threshold is lower than the theoretical range of the high-end region of charge, so it can be seen that the SOC threshold is not the theoretical boundary of the high-end region of charge but only an operating strategy.
  • the type and composition of the batteries used are different, and the SOC with fluctuations in the voltage change rate-SOC curve is different. Therefore, the state of charge threshold can be set to other appropriate values according to the type and composition of the batteries used. In some implementations, more additional conditions (such as voltage, current, etc.) can be added to determine whether the battery is in the high-end region of charging.
  • step 108 the voltage Vn, temperature Tn, and charge rate Cn at the sampling time tn and the voltage Vi at the sampling time ti are obtained, wherein the sampling time ti is to obtain the charge of the battery within the preset time period before the current sampling time tn state moment.
  • step 110 calculate the voltage difference Vn-Vi between the voltage Vn and the sampling time ti according to i from n-1, step 110; then in step 112, judge whether the calculated voltage difference Vn-Vi is greater than or equal to the preset voltage threshold, If the calculated voltage difference Vn-Vi is less than the preset voltage threshold, then return to step 110, subtract 1 from the value of i to calculate the voltage difference Vn-Vi; if the calculated voltage difference Vn-Vi is greater than or equal to the preset voltage threshold, Then proceed to step 114, that is, it is not necessary to calculate the voltage difference Vn-Vi corresponding to a smaller i value.
  • the minimum voltage difference greater than or equal to the preset voltage threshold is obtained, so that the calculated voltage change rate has the highest accuracy, so that the actual state of charge of the battery can be corrected more accurately; on the other hand, it is not necessary to calculate all the voltages
  • the difference Vn-Vi reduces the amount of calculation.
  • step 114 the rate of change of voltage is calculated according to the following formula:
  • Vn-Vj is the voltage difference of the voltage difference Vn-Vi greater than or equal to the preset voltage threshold for the first time
  • tj is the sampling time for obtaining the voltage Vj.
  • the rate of voltage change is calculated according to the following formula:
  • tj is the moment when the voltage Vj corresponding to the minimum value Vn-Vj is obtained when the voltage difference Vn-Vi is greater than or equal to the preset voltage threshold and is the minimum value.
  • the voltage change rate is calculated according to the following formula :
  • the calculated voltage change rate is filtered to obtain a smooth voltage change rate-SOC curve.
  • the voltage-SOC curve and the corresponding voltage change rate-SOC curve of the lithium iron phosphate battery are shown in Figure 3(a) and Figure 3(b), respectively.
  • the filtered rate of voltage change may be calculated according to the following formula:
  • Filtered voltage change rate K1*(voltage change rate at sampling time tn)+K2*(voltage change rate at sampling time tm)
  • the sampling time tm is the latest sampling time at which the voltage change rate is calculated before the sampling time tn
  • step 118 After obtaining the filtered voltage change rate, compare the filtered voltage change rate with the voltage change rate threshold selected in the voltage change rate-SOC relationship table stored in the BMS, step 118. If the filtered voltage change rate is less than the voltage change rate threshold or the correction flag is 0, then return to step 104; if the filtered voltage change rate is greater than or equal to the voltage change rate threshold and the correction flag is 1, then according to the battery in the sampling.
  • the temperature Tn and charge rate Cn at time tn are queried in the voltage change rate threshold-SOC lookup table to obtain the corrected state of charge of the battery, step 120 , and the flag position is set to 0.
  • Table 1 below lists the voltage change rate threshold-SOC lookup table according to one embodiment.
  • the look-up table is obtained by setting a specific temperature offline, charging at different charging rates and recording the SOC value at each rate, and the look-up table calibrated in this way is stored in the BMS.
  • FIG. 2 illustrates a flow diagram of a portion of a method for correcting a state of charge of a battery according to an embodiment of the present invention.
  • three levels of voltage change rate thresholds are set in Fig. 2, that is, the third level voltage change rate threshold, the second level voltage change rate threshold, and the first level voltage change rate threshold, where Level 3 voltage change rate threshold Level 2 voltage change rate threshold > Level 1 voltage change rate threshold.
  • step 118a After obtaining the filtered voltage change rate, compare the filtered voltage change rate with the third-level voltage change rate threshold selected in the voltage change rate-SOC relationship table stored in the BMS, step 118a, that is, judge the filtered voltage change rate Whether the voltage change rate is greater than or equal to the level 3 voltage change rate threshold for the first time.
  • the third-level correction flag is set to 0 and according to the temperature Tn and charge rate Cn of the battery at the sampling time tn , inquire in the third-level voltage change rate threshold-SOC lookup table to obtain the corrected state of charge of the battery, step 120 .
  • the filtered voltage change rate and the voltage change rate-SOC relationship table stored in the BMS Step 118b is to judge whether the filtered voltage change rate is greater than or equal to the second-stage voltage change rate threshold for the first time.
  • the second level correction flag is set to 0 and according to the temperature Tn and The charge rate Cn is queried in the second level voltage change rate threshold-SOC lookup table to obtain the corrected state of charge of the battery, step 120 .
  • step 118c select the filtered voltage change rate and the voltage change rate-SOC relationship table stored in the BMS Compared with the threshold value of the first-level voltage change rate, step 118c, that is, it is judged whether the filtered voltage change rate is greater than or equal to the first-level voltage change rate threshold for the first time.
  • the first-level correction flag is set to 0 and according to the temperature Tn and charge rate Cn of the battery at the sampling time tn , query the first-level voltage change rate threshold-SOC lookup table to obtain the corrected state of charge of the battery, step 120 .
  • the filtered voltage change rate is less than the threshold value of the first-level voltage change rate or the first-level correction flag bit is 0, return to step 104 .
  • the third-level voltage change rate threshold is 0.09
  • the second-level voltage change rate threshold is 0.07
  • the first-level voltage change rate threshold is 0.05. It can be seen from Figure 3(b) that the larger the voltage change rate threshold, the greater the voltage fluctuation, and the higher the correction accuracy; and the smaller the voltage change rate threshold, the earlier the correction opportunity is obtained.
  • the voltage change rate thresholds and their number can be set according to the batteries used, the more voltage change rate thresholds used, the more chances of correction.
  • step 118a and step 120 the temperature Tn and charging rate Cn of the battery at the sampling time tn can be compared with the preset temperature range and preset rate range corresponding to the threshold value of the third-level voltage change rate Compare, step 119.
  • the corrected state of charge of the battery is obtained by querying the third-level voltage change rate threshold-SOC lookup table according to the temperature Tn and the charging rate Cn .
  • the temperature Tn is not within the preset temperature range or the charge rate Cn is not within the preset rate range, return to step 104 .
  • the preset temperature range is 10° to 31°
  • the preset charge rate range is 0.045-1.05C.
  • the inventors of the present invention have found in research that the charging voltage of the battery presents different voltage-SOC curves under the influence of factors such as different temperatures (including initial temperature), charge rate and initial SOC, as shown in Figure 4;
  • the different curves in the high-end area are relatively scattered, and the high-end SOC corresponding to the same voltage value has a large difference, so the accuracy of the corrected SOC is low.
  • the voltage change rate shows an increasing trend, and the voltage change rate-SOC curve is relatively stable, as shown in Figure 5; the different curves in the charging high-end area are more concentrated, and the high-end SOC corresponding to the same voltage change rate value is relatively close, so the accuracy of the corrected SOC is higher.
  • the SOC correction accuracy in the charging high-end region according to the voltage and according to the voltage change rate is obtained, as shown in Table 2 below.
  • an embodiment of the present invention also provides a battery management system 500, including: at least one processor 501; and a memory 502 communicatively connected to the processor 501; wherein, the memory 502 stores There are instructions executable by the processor. When the instructions are executed by the processor 501, the instructions cause the processor 501 to execute the method for modifying the state of charge of the battery provided by the embodiment of the present invention.
  • the processor 501 and the memory 502 are electrically connected directly or indirectly to realize data transmission or interaction.
  • these components can be electrically connected through one or more communication buses or signal buses.
  • the methods for correcting the state of charge of the battery each include at least one software function module that can be stored in the memory 502 in the form of software or firmware.
  • the processor 501 may be an integrated circuit chip with signal processing capability.
  • Processor 501 can be a general-purpose processor, including CPU (Central Processing Unit, central processing unit), NP (Network Processor, network processor) etc.; Other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can realize or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present invention.
  • a general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.
  • the memory 502 can store various software programs and modules, such as program instructions/modules corresponding to the method and device for correcting the state of charge of the battery provided by the embodiments of the present invention.
  • the processor 501 executes various functional applications and data processing by running the software programs and modules stored in the memory 502, that is, implements the methods in the embodiments of the present invention.
  • Memory 502 can include but not limited to RAM (Random Access Memory, random access memory), ROM (Read Only Memory, read-only memory), PROM (Programmable Read-Only Memory, programmable read-only memory), EPROM (Erasable Programmable Read -Only Memory, erasable read-only memory), EEPROM (Electric Erasable Programmable Read-Only Memory, electrically erasable read-only memory), etc.
  • RAM Random Access Memory, random access memory
  • ROM Read Only Memory, read-only memory
  • PROM Programmable Read-Only Memory, programmable read-only memory
  • EPROM Erasable Programmable Read -Only Memory, erasable read-only memory
  • EEPROM Electrical Erasable Programmable Read-Only Memory, electrically erasable read-only memory
  • the present invention also provides a device, which includes: a battery; and a battery management system as shown in FIG. 6 .
  • Batteries may be used as a power source for the device, or as an energy storage unit for the device.
  • the device can be, but not limited to, a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a battery according to its use requirements.
  • Figure 7 is an example device.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a device may be a cell phone, tablet, laptop, or the like.

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Abstract

本发明涉及一种用于确定电池的荷电状态的方法，包括：a)获取在当前的采样时刻tn的荷电状态；b)获取在所述采样时刻tn的电压Vn、温度Tn和充电倍率Cn，以及在采样时刻ti的电压Vi，计算电压差Vn-Vi，其中采样时刻ti是在采样时刻tn之前的预设时间段内获取电池的荷电状态的时刻；c)在电压差Vn-Vi大于或等于预设电压阈值时，根据电压差Vn-Vi和时间差tn-ti计算电压变化率；以及d)在电压变化率首次大于或等于预设的电压变化率阈值时，根据电池在采样时刻tn的温度Tn和充电倍率Cn，由电池的修正荷电状态与预设的电压变化率阈值、温度、充电倍率的对应关系，获得电池的修正荷电状态作为电池的实际荷电状态。

Description

确定电池的荷电状态的方法、电池管理***及用电装置 技术领域
本发明涉及电池技术领域，特别涉及一种用于确定电池的荷电状态的方法、电池管理***以及用电装置。
背景技术
荷电状态(State of charge，SOC)是电池的剩余容量与电池完全充满电时容量的比值，表征了电池的剩余容量。在电池的使用期间，及时准确地掌握电池的SOC情况具有非常重要的意义。
目前估算电池的SOC的主要方法有安时积分法和开路电压法，其中安时积分法受到测量精度、采样频率以及初始SOC误差的影响，导致计算结果有一定的误差，并且误差会随时间持续累积，无法保证电池在长期工作时的SOC准确性。开路电压(Open Circuit Voltage，OCV)法由于电池的充电电压在不同温度和倍率等因素影响下呈现不同的电压曲线，同一电压值对应的SOC差异较大，因此获取的SOC精度较低。
发明内容
针对现有技术中存在的上述不足，本发明的目的在于提供一种用于确定电池的荷电状态的方法、电池管理***(Battery Management System，BMS)以及车辆，以提高SOC的估算精度。
为了达到上述目的，本发明的第一方面提供了一种用于确定电池的荷电状态的方法，所述方法包括：
a)获取所述电池在当前的采样时刻tn的荷电状态；
b)获取所述电池在所述采样时刻tn的电压Vn、温度Tn和充电倍率Cn，以及所述电池在采样时刻ti的电压Vi，计算所述电压Vn与所述电压Vi的电压差Vn-Vi，其中所述采样时刻ti是在所述采样时刻tn之前的预设时间段内获取所述电池的荷电状态的时刻；
c)在所述电压差Vn-Vi大于或等于所述预设电压阈值时，根据所述电压差Vn-Vi以及所述采样时刻tn与所述采样时刻ti的时间差tn-ti计算电压变化率；以及
d)在所述电压变化率大于或等于预设的电压变化率阈值时，根据所述电池在所述采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述预设的电压变化率阈值、温度、充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态。
通过使用修正荷电状态与电压变化率、温度、充电倍率的对应关系来修正电池的实际荷电状态，实现了更精确地修正电池的实际荷电状态，提高了实际SOC的精度。在优选的实施方案中，所述预设电压阈值是5mV。
在一些实施方案中，所述采样时刻ti是在所述采样时刻tn之前的所述预设时间段内获取所述电池的荷电状态的n-1个采样时刻中的任一时刻，其中n为正整数，i＝1，2，3…，n-1，并且所述方法包括：
按照i从n-1递减依次计算所述电压Vn与所述电压Vi的电压差Vn-Vi，在所述电压差Vn-Vi大于或等于所述预设电压阈值时，根据以下公式计算电压变化率：
电压变化率＝(Vn-Vj)/(tn-tj)，或
电压变化率＝所述预设电压阈值/(tn-tj)，
其中Vn-Vj是所述电压差Vn-Vi中首次大于或等于所述预设电压阈值的电压差，tj是获取电压Vj的采样时刻。
通过按照i从n-1递减依次计算电压差Vn-Vi，并且将所述电压差Vn-Vi与所述预设电压阈值进行比较，一方面获取了大于或等于所述预设电压阈值的最小电压差值，使得计算出的电压变化率精度最高，从而能够更精确地修正电池的实际荷电状态；另一方面不用计算所有电压差Vn-Vi，减少了计算量。
在另一些实施方案中，其中所述采样时刻ti是所述采样时刻tn之前的所述预设时间段内获取所述电池的荷电状态的最早采样时刻。换言之，ti是n-1个采样时刻中的最早采样时刻t1，每次仅计算Vn-V1，从而减少了计算量和中间数据的数据量。
在优选的实施方案中，当所述电池在所述采样时刻tn的荷电状态大于或等于预设荷电状态阈值时，才获取所述电池在所述采样时刻tn的电压Vn、温度Tn和充电倍率Cn，以及所述电池在采样时刻ti的电压Vi，并且计算所述电压Vn与所述电压Vi的电压差Vn-Vi。
通过在充电高端获得电压差Vn-Vi来计算电压变化率，并且使用电压变化率来修改电池的荷电状态，实现了在较宽的充电高端平台区修正电池的实际荷电状态。在本申请的实施方案中，所述充电高端是所述电池的荷电状态在所述预设的荷电状态阈值以上且所述电池的电压变化率在所述预设的电压变化率阈值以上的状态，优选地，所述预设的荷电状态阈值是70％。本领域技术人员能够理解，由于所采用电池的类型和成分决定了电池的电压变化率与SOC的曲线中波动的位置，因此预设的荷电状态阈值可以被设置为适应于所采用电池的类型和成分的阈值。
在任意实施方案中，步骤d)包括：
d1)当所述电压变化率大于或等于所述预设的电压变化率阈值时，将所述电池在所述采样时刻tn的温度Tn和充电倍率Cn与所述预设的电压变化率阈值对应的预设温度范围和预设倍率范围进行比较；以及
d2)当所述电池在所述采样时刻tn的温度Tn和充电倍率Cn均在所述预设温度范围内和所述预设倍率范围内时，才根据所述电池在采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述预设的电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态。
通过判断温度和充电倍率是否在预设的范围内，避免了对应关系以外的异常数据出现。
在任意实施方案中，其中所述预设的电压变化率阈值包括k级电压变化率阈值，并且所述方法包括：
在所述电压变化率大于或等于第x级电压变化率阈值且第x级修正标志位为1时，根据所述电池在采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述第x级电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态，并且将所述第x级修正标志位置0；
在所述电压变化率小于所述第x级电压变化率阈值或者所述第x级修正标志位为0时，将所述电压变化率与第x-1级电压变化率阈值进行比较；
其中x＝k，k-1，……，3，2，且k大于或等于3，并且所述第x级电压变化率阈值大于所述第x-1级电压变化率阈值；
在所述电压变化率大于或等于所述第1级电压变化率阈值且第1级修正标志位为1时，根据所述电池在采样时刻tn的温度Tn和充电倍率Cn， 由所述电池的修正荷电状态与所述第1级电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态，并且将所述第1级修正标志位置0；以及
在所述电压变化率小于所述第1级电压变化率阈值或者所述第1级修正标志位为0时，返回步骤b)。
通过设置多级电压变化率阈值，可以实现对SOC的多次修正，电压变化率阈值的级数越多，修正SOC的机会越多，并且电压变化率阈值越低，可以获得越早的修正机会。
在任意实施方案中，所述方法包括：对所述电压变化率进行滤波，并且在步骤d)中用经滤波的电压变化率与所述预设的电压变化率阈值进行比较。
由于采样误差或噪声误差会带来电压波动，通过滤波可以减少采样误差或噪声误差所引起的电压波动的影响。
在一些实施方案中，所述经滤波的电压变化率根据以下公式来计算：
经滤波的电压变化率＝K1*(采样时刻tn的电压变化率)+K2*(采样时刻tm的电压变化率)，
其中采样时刻tm是所述采样时刻tn之前计算出电压变化率的最近一次采样时刻，K1和K2是权重系数并且K1+K2＝1。
本领域技术人员应理解，上述对电压变化率进行滤波的算法是示例性的，在其他实施方案中可以采用任何合适的滤波算法来对电压变化率进行滤波。
在任意实施方案中，所述方法在步骤b)之前包括：
a1)判断所述电池是否处于充电状态，若是，则执行下一步；若否， 则重复步骤a1)；
a2)检测并判断充电电流是否稳定以及所述电池在所述采样时刻tn的电压是否有效，若是，则执行下一步；若否，则返回步骤a1)。
通过判断电池是否处于充电状态，限定了仅在充电期间修正SOC。通过限定充电电流稳定，确保了电池处于恒流充电状态，从而保证了修正SOC的准确性。
此外，在例如采样芯片出错的情况下，电压的采样值有可能出错，由于本发明的总体构思是以采样的电压值为基础，因此判断当前电压是否有效确保了修正SOC的可靠性。在一些实施方案中，根据所述电池在所述采样时刻tn的电压是否超出预设的采样范围来判断当前电压是否有效，即所述电池在所述采样时刻tn的电压在所述预设的采样范围以外时不是有效电压。例如，磷酸铁锂电池的正常电压范围在1.5V-4.5V之间，在一个实施例中，根据所述电池在所述采样时刻tn的电压是否在500mV-6000mV之间来判断该电压是否有效，即低于500mV或高于6000mV的电压不是有效电压。
本领域技术人员应理解，本发明的第一方面的以及第一方面的任一种可能的实施方案中所述的用于修正电池的荷电状态的方法可以与其他SOC估计方法相结合，以为电池提供更加准确的SOC估计。
本发明的第二方面提供了一种电池管理***，所述电池管理***包括：至少一个处理器；以及与所述至少一个处理器连接的存储器；其中所述存储器存储有指令，当所述指令被所述至少一个处理器执行时，所述指令导致所述至少一个处理器执行如本发明的第一方面以及第一方面的任一种可能的实施方案中所述的用于修正电池的荷电状态的方法。
本发明的第三方面提供了一种装置，所述装置包括：电池；以及根据 本发明的第二方面的电池管理***。所述电池可以用作所述装置的电源，也可以用作所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能***等。所述装置可以根据其使用需求来选择电池。
附图说明
为了更清楚地说明本发明的技术方案，下面将对本发明实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本发明的一些实施方案，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1例示了根据本发明的一个实施方案的用于修正电池的荷电状态的方法的流程图。
图2例示了根据本发明的一个实施方案的用于修正电池的荷电状态的方法的一部分的流程图。
图3(a)和图3(b)分别例示了根据本发明的一个实施方案的磷酸铁锂电池的电压-SOC曲线和电压变化率-SOC曲线的示意图。
图4是根据本发明的一个实施方案的电池在不同温度和充电倍率下的多个电压-SOC曲线的示意图。
图5是根据本发明的一个实施方案的电池在不同温度和充电倍率下的多个电压变化率-SOC曲线的示意图。
图6是本发明的一个实施方案的电池管理***的示意图。
图7是本发明的一个实施方案的包含电池管理***的用电装置的示意 图。
具体实施方式
下面将结合附图来对本发明的实施方案进行进一步详述。
图1例示了根据本发明的一个实施方案的用于修正电池的荷电状态的方法的流程图。本发明的修正电池的荷电状态的方法主要在电池的充电高端区域修正电池的SOC。
如图1所示，在步骤102，根据充电电流的流向检测电池是否处于充电状态，如果电池处于充电状态，则进入步骤104，否则重复步骤102。在一些实施方案中，在步骤102中不仅检测电池是否处于充电状态，还检测充电电流是否稳定以及电池的当前电压是否有效。具体地，在一些实施方案中，通过检测充电电流是否波动来判断充电电流是否处于恒流充电状态，即具有恒定的充电倍率。此外，在一些实施方案中，根据电池的当前电压是否超出预设的采样范围来判断当前电压是否有效，即当前电压在预设采样范围以外时不是有效电压。例如，磷酸铁锂电池的正常电压范围在2.5V-3.65V之间，在一个实施例中，根据所述电池在所述采样时刻tn的电压是否在500mV-6000mV之间来判断该电压是否有效，即低于500mV或高于6000mV的电压不是有效电压。
通常，电池管理***(BMS)一直以某个预设的采样周期来获取或推算电池的SOC并采集电池的电压、温度和充电倍率等数据；假设当前的采样时刻为tn，则采样时刻tn采集到的电压为Vn，温度为Tn，充电倍率为Cn，当前的采样时刻tn的前一个采样时刻为tn-1。在本发明的实施方案中，当前的采样时刻tn是最近一次的采样时刻，采样时刻tn-1是第二近的采样时刻。
在步骤104，获取电池在当前的采样时刻tn的SOC；然后，在步骤106中，检测电池是否处于充电高端区域。在一些实施方案中，通过判断电池的荷电状态是否大于预设荷电状态阈值来判断电池是否处于充电高端区域；如果电池处于充电高端区域，则进入步骤108，否则重复步骤104。如图3(b)所示，磷酸铁锂电池的电压变化率-SOC曲线在20％SOC左右和60％SOC左右都有一个明显的突起，而本发明的实施方案不适用于这种电压变化率的波动。因此，在图3(a)和图3(b)的磷酸铁锂电池的实施方案中，荷电状态阈值可以被设置为70％，以避开图3(b)中的电压变化率的波动位置；然而，图3(a)示出了充电高端区域的理论范围，其中荷电状态阈值低于充电高端区域的理论范围，由此可见荷电状态阈值并非是充电高端区域的理论边界而只是一个操作策略。在其他实施方案中，所采用电池的类型和成分不同，电压变化率-SOC曲线存在波动的SOC不同，因此荷电状态阈值可以根据所采用电池的类型和成分等来设置成其他合适的值。在一些实施方案中，还可以添加更多的附加条件(诸如电压、电流等)来判断电池是否处于充电高端区域。
在步骤108，获取采样时刻tn的电压Vn、温度Tn和充电倍率Cn以及在采样时刻ti的电压Vi，其中采样时刻ti是在当前的采样时刻tn之前的预设时间段内获取电池的荷电状态的时刻。在一实施方案中，采样时刻ti是在当前的采样时刻tn之前的预设时间段内获取电池的荷电状态的n-1个采样时刻中的任一时刻，其中n为正整数，i＝1，2，3…，n-1。然后，按照i从n-1递减计算电压Vn与采样时刻ti的电压差Vn-Vi，步骤110；接着在步骤112中，判断计算出的电压差Vn-Vi是否大于或等于预设电压阈值，如果计算出的电压差Vn-Vi小于预设电压阈值，则返回步骤110，将i的值减1计算电压差Vn-Vi；如果计算出的电压差Vn-Vi大于或等于预设电压阈值，则前进到步骤114，即不用再计算更小的i值对应的电压 差Vn-Vi。这样一方面获取了大于或等于所述预设电压阈值的最小电压差值，使得计算出的电压变化率精度最高，从而能够更精确地修正电池的实际荷电状态；另一方面不用计算所有电压差Vn-Vi，减少了计算量。
在一个实施方案中，在步骤114中，根据以下公式计算电压变化率：
电压变化率＝(Vn-Vj)/(tn-tj)，
其中Vn-Vj是电压差Vn-Vi中首次大于或等于预设电压阈值的电压差，tj是获取电压Vj的采样时刻。
在另一实施方案中，根据以下公式计算电压变化率：
电压变化率＝预设电压阈值/(tn-tj)，
其中tj是满足电压差Vn-Vi大于或等于预设电压阈值且为最小值时获取最小值Vn-Vj的对应电压Vj的时刻。
在又一实施方案中，仅计算电压差Vn-V1，将电压差Vn-V1与预设电压阈值进行比较，在电压差Vn-V1大于等于预设电压阈值时，根据以下公式计算电压变化率：
电压变化率＝Vn-V1/(tn-t1)。
在计算出电压变化率之后，在步骤116中，对计算出的电压变化率进行滤波，得到平滑的电压变化率-SOC曲线。磷酸铁锂电池的电压-SOC曲线和对应的电压变化率-SOC曲线分别如图3(a)和图3(b)所示。在一实施方案中，可以根据以下公式来计算经滤波的电压变化率：
经滤波的电压变化率＝K1*(采样时刻tn的电压变化率)+K2*(采样时刻tm的电压变化率)
其中采样时刻tm是采样时刻tn之前计算出电压变化率的最近一次采样时刻，K1和K2是权重系数并且K1+K2＝1。
在获得经滤波的电压变化率后，将经滤波的电压变化率与BMS中存 储的电压变化率-SOC关系表中选取的电压变化率阈值进行比较，步骤118。如果经滤波的电压变化率小于电压变化率阈值或者修正标志位为0，则返回步骤104；如果经滤波的电压变化率大于或等于电压变化率阈值并且修正标志位为1，则根据电池在采样时刻tn的温度Tn和充电倍率Cn，在电压变化率阈值-SOC查询表中查询得到电池的修正荷电状态，步骤120，并且将修正标志位置0。下面的表1列出了根据一个实施例的电压变化率阈值-SOC查询表。该查询表通过线下设定特定的温度、以不同的充电倍率下进行充电并记录每个倍率下的SOC值来获得，并且这样标定出的查询表被存储在BMS中。
表1 电压变化率阈值-SOC查询表
Figure PCTCN2021097255-appb-000001
图2例示了根据本发明的一个实施方案的用于修正电池的荷电状态的方法的一部分的流程图。与图1中示出的流程图不同，在图2中设置了三级电压变化率阈值，即第3级电压变化率阈值、第2级电压变化率阈值、第1级电压变化率阈值，其中第3级电压变化率阈值第2级电压变化率阈值>第1级电压变化率阈值。
在获得经滤波的电压变化率后，将经滤波的电压变化率与BMS中存储的电压变化率-SOC关系表中选取的第3级电压变化率阈值进行比较，步骤118a，即判断经滤波的电压变化率是否首次大于或等于第3级电压变 化率阈值。在经滤波的电压变化率大于或等于第3级电压变化率阈值并且第3级修正标志位为1时，将第3级修正标志位置0并且根据电池在采样时刻tn的温度Tn和充电倍率Cn，在第3级电压变化率阈值-SOC查询表中查询得到电池的修正荷电状态，步骤120。
在经滤波的电压变化率小于第3级电压变化率阈值或者第3级修正标志位为0时，将经滤波的电压变化率与BMS中存储的电压变化率-SOC关系表中选取的第2级电压变化率阈值进行比较，步骤118b，即判断经滤波的电压变化率是否首次大于或等于第2级电压变化率阈值。类似地，在经滤波的电压变化率大于或等于第2级电压变化率阈值并且第2级修正标志位为1时，将第2级修正标志位置0并且根据电池在采样时刻tn的温度Tn和充电倍率Cn，在第2级电压变化率阈值-SOC查询表中查询得到电池的修正荷电状态，步骤120。
类似地，在经滤波的电压变化率小于第2级电压变化率阈值或者第2级修正标志位为0时，将经滤波的电压变化率与BMS中存储的电压变化率-SOC关系表中选取的第1级电压变化率阈值进行比较，步骤118c，即判断经滤波的电压变化率是否首次大于或等于第1级电压变化率阈值。在经滤波的电压变化率大于或等于第1级电压变化率阈值并且第1级修正标志位为1时，将第1级修正标志位置0并且根据电池在采样时刻tn的温度Tn和充电倍率Cn，在第1级电压变化率阈值-SOC查询表中查询得到电池的修正荷电状态，步骤120。在经滤波的电压变化率小于第1级电压变化率阈值或者第1级修正标志位为0时，返回步骤104。
在一个优选实施例中，第3级电压变化率阈值为0.09，第2级电压变化率阈值为0.07，并且第1级电压变化率阈值为0.05。从图3(b)可知，电压变化率阈值越大，电压波动越大，修正精度越高；而电压变化率阈值 越小，获得的修正机会越早。本领域技术人员可以理解，可以根据使用的电池来设定电压变化率阈值及其数量，使用的电压变化率阈值越多，修正的机会越多。
此外，如图2所示，在步骤118a与步骤120之间，可以将电池在采样时刻tn的温度Tn和充电倍率Cn与第3级电压变化率阈值对应的预设温度范围和预设倍率范围进行比较，步骤119。在温度Tn在预设温度范围内且充电倍率Cn在预设倍率范围内时，才根据温度Tn和充电倍率Cn在第3级电压变化率阈值-SOC查询表中查询获得电池的修正荷电状态。在温度Tn不在预设温度范围内或充电倍率Cn不在预设倍率范围内时，返回步骤104。在表1的实施例中，预设温度范围是10°至31°，预设充电倍率范围是0.045-1.05C。通过判断温度和充电倍率是否在预设的范围内，避免了第3级电压变化率阈值-SOC查询表以外的异常数据出现。类似地，在步骤118b与步骤120之间，可以将温度Tn和充电倍率Cn与第2级电压变化率阈值对应的预设温度范围和预设倍率范围进行比较；在步骤118c与步骤120之间，可以将温度Tn和充电倍率Cn与第1级电压变化率阈值对应的预设温度范围和预设倍率范围进行比较。
本发明的发明人在研究中发现，电池的充电电压在不同温度(包括起始温度)、充电倍率和起始SOC等因素影响下呈现不同的电压-SOC曲线，如图4所示；在充电高端区域不同曲线之间较为分散，同一电压值对应的高端SOC差异较大，因此修正得到的SOC精度较低。与此相比，电压变化率呈现的是增长趋势，电压变化率-SOC曲线较为平稳，如图5所示；在充电高端区域不同曲线之间较为集中，同一电压变化率值对应的高端SOC相对接近，因此修正得到的SOC精度较高。根据大量的实验及统计，得到了根据电压和根据电压变化率在充电高端区域的SOC修正精度，如下面的表2所示。
表2 根据电压和根据电压变化率在充电高端区域的SOC修正精度
SOC 80 85 90 95 100
电压 ＜6％ ＜5％ ＜3％ ＜2％ 0
微分 ＜3％ ＜2％ ＜2％ ＜1％ 0
基于同一发明构思，请参照图6，本发明的实施方案中还提供一种电池管理***500，包括：至少一个处理器501；以及，与处理器501通信连接的存储器502；其中，存储器502存储有可被处理器执行的指令，当指令被处理器501执行时，指令导致处理器501能够执行本发明的实施方案所提供的用于修正电池的荷电状态的方法。
其中，处理器501和存储器502之间直接或间接地电连接，以实现数据的传输或交互。例如，这些元件之间可以通过一条或多条通讯总线或信号总线实现电连接。用于修正电池的荷电状态的方法分别包括至少一个可以以软件或固件(firmware)的形式存储于存储器502中的软件功能模块。
处理器501可以是一种集成电路芯片，具有信号处理能力。处理器501可以是通用处理器，包括CPU(Central Processing Unit，中央处理器)、NP(Network Processor，网络处理器)等；还可以是数字信号处理器、专用集成电路、现成可编程门阵列或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件。其可以实现或者执行本发明的实施方案中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
存储器502可以存储各种软件程序以及模块，如本发明的实施方案提供的用于修正电池的荷电状态的方法及装置对应的程序指令/模块。处理器501通过运行存储在存储器502中的软件程序以及模块，从而执行各种功能应用以及数据处理，即实现本发明的实施方案中的方法。
存储器502可以包括但不限于RAM(Random Access Memory，随机 存取存储器)，ROM(Read Only Memory，只读存储器)，PROM(Programmable Read-Only Memory，可编程只读存储器)，EPROM(Erasable Programmable Read-Only Memory，可擦除只读存储器)，EEPROM(Electric Erasable Programmable Read-Only Memory，电可擦除只读存储器)等。
前述用于修正电池的荷电状态的方法中的各实施方案和具体实施例同样适用于图6所示的电池管理***500，通过前述用于修正电池的荷电状态的方法的详细描述，本领域技术人员可以清楚的知道图6中的电池管理***500的实施方法，所以为了说明书的简洁，在此不再详述。
另外，本发明还提供一种装置，所述装置包括：电池；以及如图6所示的电池管理***。电池可以用作所述装置的电源，也可以用作装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能***等。所述装置可以根据其使用需求来选择电池。
图7是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。
虽然已经参考优选实施例对本发明进行了描述，但在不脱离本发明的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本发明并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (11)

  1. 一种用于确定电池的荷电状态的方法，所述方法包括：
    a)获取所述电池在当前的采样时刻tn的荷电状态；
    b)获取所述电池在所述采样时刻tn的电压Vn、温度Tn和充电倍率Cn，以及所述电池在采样时刻ti的电压Vi，计算所述电压Vn与所述电压Vi的电压差Vn-Vi，其中所述采样时刻ti是在所述采样时刻tn之前的预设时间段内获取所述电池的荷电状态的时刻；
    c)在所述电压差Vn-Vi大于或等于所述预设电压阈值时，根据所述电压差Vn-Vi以及所述采样时刻tn与所述采样时刻ti的时间差tn-ti计算电压变化率；以及
    d)在所述电压变化率大于或等于预设的电压变化率阈值时，根据所述电池在所述采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述预设的电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态。
  2. 根据权利要求1所述的方法，其中所述采样时刻ti是在所述采样时刻tn之前的所述预设时间段内获取所述电池的荷电状态的n-1个采样时刻中的任一时刻，其中n为正整数，i＝1，2，3…，n-1，并且所述方法包括：
    按照i从n-1递减依次计算所述电压Vn与所述电压Vi的电压差Vn-Vi，在所述电压差Vn-Vi大于或等于所述预设电压阈值时，根据以下公式计算电压变化率：
    电压变化率＝(Vn-Vj)/(tn-tj)，或
    电压变化率＝所述预设电压阈值/(tn-tj)，
    其中Vn-Vj是所述电压差Vn-Vi中首次大于或等于所述预设电压阈值 的电压差，tj是获取电压Vj的采样时刻。
  3. 根据权利要求1所述的方法，其中所述采样时刻ti是所述采样时刻tn之前的所述预设时间段内获取所述电池的荷电状态的最早采样时刻。
  4. 根据权利要求1至3中任一项所述的方法，其中当所述电池在所述采样时刻tn的荷电状态大于或等于预设荷电状态阈值时，才获取所述电池在所述采样时刻tn的电压Vn、温度Tn和充电倍率Cn，以及所述电池在采样时刻ti的电压Vi，并且计算所述电压Vn与所述电压Vi的电压差Vn-Vi。
  5. 根据权利要求1至4中任一项所述的方法，其中步骤d)包括：
    d1)当所述电压变化率大于或等于所述预设的电压变化率阈值时，将所述电池在所述采样时刻tn的温度Tn和充电倍率Cn与所述预设的电压变化率阈值对应的预设温度范围和预设倍率范围进行比较；以及
    d2)当所述电池在所述采样时刻tn的温度Tn和充电倍率Cn均在所述预设温度范围内和所述预设倍率范围内时，才根据所述电池在采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述预设的电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态。
  6. 根据权利要求1至5中任一项所述的方法，其中所述预设的电压变化率阈值包括k级电压变化率阈值，并且所述方法包括：
    在所述电压变化率大于或等于第x级电压变化率阈值且第x级修正标志位为1时，根据所述电池在采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述第x级电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态，并且将所述第x级修正标志位置0；
    在所述电压变化率小于所述第x级电压变化率阈值或者所述第x级修 正标志位为0时，将所述电压变化率与第x-1级电压变化率阈值进行比较；
    其中x＝k，k-1，……，3，2，且k大于或等于3，并且所述第x级电压变化率阈值大于所述第x-1级电压变化率阈值；
    在所述电压变化率大于或等于所述第1级电压变化率阈值且第1级修正标志位为1时，根据所述电池在采样时刻tn的温度Tn和充电倍率Cn，由所述电池的修正荷电状态与所述第1级电压变化率阈值、温度和充电倍率的对应关系，获得所述电池的修正荷电状态作为所述电池的实际荷电状态，并且将所述第1级修正标志位置0；以及
    在所述电压变化率小于所述第1级电压变化率阈值或者所述第1级修正标志位为0时，返回步骤b)。
  7. 根据权利要求1至6中任一项所述的方法，其中所述方法包括：
    对所述电压变化率进行滤波，并且在步骤d)中用经滤波的电压变化率与所述预设的电压变化率阈值进行比较。
  8. 根据权利要求7中所述的方法，其中所述经滤波的电压变化率根据以下公式来计算：
    经滤波的电压变化率＝K1*(采样时刻tn的电压变化率)+K2*(采样时刻tm的电压变化率)，
    其中采样时刻tm是所述采样时刻tn之前计算出电压变化率的最近一次采样时刻，K1和K2是权重系数并且K1+K2＝1。
  9. 根据权利要求1至8中任一项所述的方法，其中所述方法在步骤b)之前包括：
    a1)判断所述电池是否处于充电状态，若是，则执行下一步；若否，则重复步骤a1)；
    a2)检测并判断充电电流是否稳定以及所述电池在所述采样时刻tn的 电压是否有效，若是，则执行下一步；若否，则返回步骤a1)。
  10. 一种电池管理***，所述电池管理***包括：
    至少一个处理器；以及
    与所述至少一个处理器连接的存储器；
    其中所述存储器存储有指令，当所述指令被所述至少一个处理器执行时，所述指令导致所述至少一个处理器执行权利要求1-9中任一项所述的用于修正电池的荷电状态的方法。
  11. 一种用电装置，所述用电装置包括：
    电池；以及
    根据权利要求10所述的电池管理***。
PCT/CN2021/097255 2021-05-31 2021-05-31 确定电池的荷电状态的方法、电池管理***及用电装置 WO2022252015A1 (zh)

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