WO2022241766A1 - 电池放电欠压保护方法、电池装置及用电装置 - Google Patents

电池放电欠压保护方法、电池装置及用电装置 Download PDF

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Publication number
WO2022241766A1
WO2022241766A1 PCT/CN2021/095187 CN2021095187W WO2022241766A1 WO 2022241766 A1 WO2022241766 A1 WO 2022241766A1 CN 2021095187 W CN2021095187 W CN 2021095187W WO 2022241766 A1 WO2022241766 A1 WO 2022241766A1
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Prior art keywords
battery
discharge
capacity ratio
voltage value
voltage
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PCT/CN2021/095187
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English (en)
French (fr)
Inventor
沈正斌
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东莞新能安科技有限公司
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Application filed by 东莞新能安科技有限公司 filed Critical 东莞新能安科技有限公司
Priority to PCT/CN2021/095187 priority Critical patent/WO2022241766A1/zh
Priority to JP2021540790A priority patent/JP2023531569A/ja
Priority to EP21940219.5A priority patent/EP4344012A1/en
Publication of WO2022241766A1 publication Critical patent/WO2022241766A1/zh
Priority to US18/512,128 priority patent/US20240085483A1/en

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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]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. 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]
    • G01R31/374—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]
    • G01R31/382—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
    • 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
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00306—Overdischarge protection
    • 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]
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
    • H02J7/007194—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of batteries, in particular to a battery discharge and undervoltage protection method, a battery device and an electrical device.
  • the fixed undervoltage protection point is set within the range of 2.8V to 3.0V.
  • the general protection point is: first-level undervoltage alarm: 3.0V , Second-level undervoltage protection: 2.9V; third-level undervoltage protection: 2.8V.
  • first-level undervoltage alarm 3.0V
  • Second-level undervoltage protection 2.9V
  • third-level undervoltage protection 2.8V.
  • the present application provides a battery discharge undervoltage protection method, a battery device and an electrical device, which can solve the problem that the discharge capacity ratio of the battery decreases at low temperature.
  • the battery discharge undervoltage protection method in an embodiment of the present application includes: acquiring the temperature value and the first voltage value of the battery; determining the discharge depth of the battery according to the temperature value; determining the discharge depth of the battery according to the first voltage value The first remaining capacity ratio of the battery; according to the first remaining capacity ratio, the discharge depth and the first undervoltage threshold, determine a second undervoltage threshold to increase the discharge capacity ratio of the battery; wherein, the The first undervoltage threshold is a preset undervoltage threshold, and the second undervoltage threshold is a dynamically adjusted undervoltage threshold.
  • the determining the discharge depth of the battery according to the temperature value includes: determining the temperature range corresponding to the temperature value; and determining the temperature range corresponding to the temperature range according to the temperature range. the depth of discharge.
  • the determining the first remaining capacity ratio of the battery according to the first voltage value includes: determining the first remaining capacity ratio corresponding to the first voltage value according to the parameter correspondence relationship of the battery.
  • the first remaining capacity ratio wherein, the corresponding parameter relationship refers to the corresponding relationship between the remaining capacity ratio and the open circuit voltage.
  • the determining the second undervoltage threshold according to the first remaining capacity ratio, the depth of discharge, and the first undervoltage threshold includes: according to the first remaining capacity ratio and the Depth of discharge, determining the second remaining capacity ratio of the battery; determining a second voltage value corresponding to the second remaining capacity ratio according to the parameter correspondence; and determining a second voltage value corresponding to the second remaining capacity ratio according to the second voltage value and the first voltage value , determining the variation of the voltage value of the battery; and determining the second undervoltage threshold according to the variation of the voltage value and the first undervoltage threshold.
  • the method further includes: obtaining the A third voltage value after discharge is cut off; according to the second undervoltage threshold and the third voltage value, determine whether to perform undervoltage protection on the battery.
  • the determining whether to perform undervoltage protection on the battery according to the second undervoltage threshold and the third voltage value includes: determining a fourth voltage threshold according to the third voltage value. voltage value; if the fourth voltage value is less than the second undervoltage threshold, it is determined to perform undervoltage protection on the battery.
  • the method before determining the first remaining capacity ratio corresponding to the first voltage value according to the parameter correspondence of the battery, the method further includes: charging the battery , until the capacity of the battery reaches the full charge capacity; obtain the full charge voltage corresponding to the full charge capacity; discharge the battery until the voltage of the battery reaches the discharge cut-off voltage; obtain the discharge process of the battery The voltage value corresponding to the voltage value and the state of charge corresponding to the voltage value; according to the voltage value and the state of charge corresponding to the voltage value, the corresponding relationship of the parameters is determined.
  • the determining the second remaining capacity ratio of the battery according to the first remaining capacity ratio and the depth of discharge includes: determining the second remaining capacity ratio of the battery according to the first remaining capacity ratio.
  • the battery device includes a battery, a processor, and a memory, and a computer program is stored in the memory.
  • the computer program is executed by the processor, the battery discharge undervoltage protection according to the embodiment of the present application is realized. method.
  • An electric device includes a load and the battery device according to the embodiment of the present application, and the battery device is used to provide electric energy for the load.
  • the electrical device includes any one of a drone, an electric vehicle, an electric tool, and an energy storage product.
  • the embodiment of the present application determines the second undervoltage threshold through the temperature value of the battery, the first voltage value and the first undervoltage threshold, and then determines the undervoltage threshold in different temperature ranges, so as to select different undervoltages in different temperature ranges threshold, so as to realize the dynamic adjustment of the undervoltage threshold and increase the discharge capacity ratio of the battery at low temperature. Moreover, in the embodiment of the present application, it is determined whether to perform undervoltage protection on the battery according to the third voltage of the battery after the cut-off discharge and the second undervoltage threshold, so as to avoid prematurely performing undervoltage protection on the battery, The discharge capacity ratio of the battery at low temperature is guaranteed.
  • Figure 1 is a graph of the voltage versus discharge capacity ratio of a battery at different temperatures.
  • FIG. 2 is a block diagram of a battery device according to an embodiment of the present application.
  • FIG. 3 is a flowchart of a battery discharge undervoltage protection method according to an embodiment of the present application.
  • FIG. 4 is a flow chart of a battery discharge undervoltage protection method according to another embodiment of the present application.
  • FIG. 5 is a flowchart of a battery discharge undervoltage protection method according to another embodiment of the present application.
  • FIG. 6 is a flowchart of a battery discharge undervoltage protection method according to another embodiment of the present application.
  • FIG. 7 is a flowchart of a battery discharge undervoltage protection method according to another embodiment of the present application.
  • Figure 8 is the open circuit voltage curve of the battery under different working conditions.
  • Figure 9 is the open-circuit voltage curves at different temperatures after the battery has been discharged.
  • FIG. 1 is a graph of the voltage-to-discharge capacity ratio of a battery at different temperatures.
  • S11 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 45°C.
  • S12 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 25°C.
  • S13 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 15°C.
  • S14 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 0°C.
  • S15 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at -10°C.
  • S16 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at -20°C.
  • the temperature refers to the ambient temperature
  • the battery at different temperatures means that the battery is at different ambient temperatures
  • the voltage refers to the open circuit voltage (Open Circuit Voltage, OCV) of the battery, that is, the terminal voltage of the battery in an open circuit state.
  • OCV Open Circuit Voltage
  • the discharge capacity ratio refers to the percentage of the discharged capacity of the battery to the rated capacity.
  • Table 1 shows the discharge capacity ratio of the battery at different temperatures. Please refer to FIG. 1 and Table 1 together. Firstly, the battery is charged at the same temperature (eg 25°C) with the same charge rate (eg 0.3C). Then, the battery is discharged at the same discharge rate (for example, 0.3C) and different temperatures until the voltage of the battery reaches the discharge cut-off voltage (for example, 2.5V). Finally, the discharge capacity ratio of the battery is determined. It can be known from Table 1 that as the temperature decreases, the discharge capacity ratio of the battery will drop sharply.
  • the present application provides a battery discharge undervoltage protection method, a battery device and an electrical device, which can increase the discharge capacity ratio of the battery at low temperature.
  • FIG. 2 is a block diagram of the battery device 20 .
  • the battery device 20 includes a memory 21 , a processor 22 , a battery 23 and a sensor 24 , and the above components can be connected through a bus or directly.
  • the memory 21 is used for storing program codes and various data, and completes program or data access during the operation of the battery device 20 .
  • the memory 21 may be an internal memory of the battery device 20 , that is, a memory built in the battery device 20 . In other implementation manners, the memory 21 may also be an external memory of the battery device 20 , that is, a memory externally connected to the battery device 20 .
  • the memory 21 includes a volatile or non-volatile storage device, such as a digital versatile disc (Digital Versatile Disc, DVD) or other optical discs, magnetic disks, hard disks, smart memory cards (Smart Media Card, SMC), secure digital (Secure Digital, SD) card, flash memory card (Flash Card), etc.
  • a digital versatile disc Digital Versatile Disc, DVD
  • other optical discs magnetic disks
  • hard disks smart memory cards
  • smart memory cards Smart Media Card, SMC
  • secure digital (Secure Digital, SD) card Secure Digital, SD card
  • flash memory card Flash Card
  • the processor 22 includes a central processing unit (Central Processing Unit, CPU), a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • CPU Central Processing Unit
  • DSP Digital Signal Processor
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programmable Gate Array
  • FPGA Field-Programmable Gate Array
  • the battery 23 is a rechargeable battery for providing electric energy to the battery device 20 .
  • the battery 23 may be a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-ion battery, a lithium polymer battery, a lithium iron phosphate battery, and the like.
  • the battery 23 includes electric cores.
  • the sensor 24 can be arranged on the surface of the electric core, and the ambient temperature can be obtained by measuring the temperature of the electric core surface.
  • the sensor 24 is a negative temperature coefficient (Negative Temperature Coefficient, NTC) thermistor.
  • NTC Negative Temperature Coefficient
  • the battery device 20 may also include other sensors, such as a voltage sensor, a current sensor, a light sensor, a gyroscope, a hygrometer, an infrared sensor, and the like.
  • the battery device 20 may also include more or fewer components, or have different configurations of components.
  • the battery device 20 can be applied to an electric device 10, which includes, but is not limited to, a drone, an electric vehicle, an electric tool, an energy storage product, and the like.
  • the electric tools include, but are not limited to, electric screwdrivers, electric drills, electric wrenches, angle grinders, steel machines, electric picks, electric hammers, marble machines, jigsaws, and the like.
  • the energy storage products include, but are not limited to, mobile phones, tablet computers, e-book readers, computers, workstations, servers, personal digital assistants (Personal Digital Assistant, PDA), portable multimedia players (Portable Multimedia Player, PMP), Mobile medical equipment, cameras, wearable devices, photovoltaic inverters, wind power converters, energy storage systems, new energy vehicle drive systems, photovoltaic equipment, etc.
  • PDA Personal Digital Assistant
  • PMP portable multimedia players
  • PMP Portable Multimedia Player
  • Mobile medical equipment cameras, wearable devices, photovoltaic inverters, wind power converters, energy storage systems, new energy vehicle drive systems, photovoltaic equipment, etc.
  • the electrical device 10 includes the battery device 20 and a load 11 , and the battery device 20 is used to provide electric energy for the load 11 .
  • the load 11 includes, but is not limited to, a refrigerator, a cold drink machine, an air conditioner, an electric fan, a ventilation fan, a hot and cold air fan, an air dehumidifier, a washing machine, a clothes dryer, an electric iron, a vacuum cleaner, a floor waxing machine, a microwave oven, Induction cooker, electric oven, electric rice cooker, dish washer, electric water heater, electric blanket, electric quilt, electric clothing, space heater, electric shaver, hair dryer, hair styler, ultrasonic face wash, electric massager, Micro-projectors, TV sets, radios, tape recorders, video recorders, video cameras, combined stereos, smoke and fire alarms, electric bells, lights, computers, etc.
  • the battery device 20 further includes a battery management system (Battery Management System, BMS).
  • BMS Battery Management System
  • the battery 23 is connected to the processor 22 through the battery management system, so as to implement functions such as charging, discharging and power consumption management through the battery management system.
  • the battery management system can communicate with the energy storage converter (Power Conversion System, PCS).
  • PCS Power Conversion System
  • FIG. 3 is a flow chart of a battery discharge undervoltage protection method according to an embodiment.
  • the battery discharge undervoltage protection method includes the following steps:
  • the temperature value of the battery 23 refers to the temperature value of the environment where the battery 23 is located.
  • the quiescent state refers to a state in which the charging or discharging current of the battery 23 approaches 0A. In one of the implementation manners, the state in which the charging or discharging current of the battery 23 is less than 0.5A is defined as the resting state.
  • the battery device 20 acquires the temperature value of the battery 23 (for example, any temperature value from -20° C. to 50° C.) through the sensor 24 .
  • the battery device 20 obtains the first voltage value U 1 of the battery 23 (for example, any voltage value from 2.0V to 3.6V) through the battery management system.
  • the battery device 20 can obtain the temperature value of the battery 23 and the first voltage value U 1 in real time, or obtain the temperature of the battery 23 according to a preset time interval (such as 1s or 2s, etc.). value and the first voltage value U 1 .
  • the preset time interval can be determined according to specific requirements.
  • the depth of discharge refers to the percentage of the discharged capacity of the battery 23 to the rated capacity. It can be understood that, in the embodiment of the present application, the value of the discharge depth of the battery 23 is equal to the value of the discharge capacity ratio.
  • the battery device 20 determines the temperature range corresponding to the temperature value according to the collected temperature value. It can be understood that there is a certain correspondence between the discharge depth and the temperature range. When the battery 23 is in different temperature ranges, the discharge depths are also correspondingly different. When the temperature range is determined, the discharge depth is also correspondingly determined. For example, when the temperature range is 15° C. to 45° C., the discharge depth is 95%. When the temperature range is -20°C to -10°C, the discharge depth is 70%.
  • the corresponding relationship between the discharge depth and the temperature range may be determined according to the design requirements of the battery 23 .
  • the discharge depths of the battery 23 at different temperature ranges may be preset.
  • the remaining capacity ratio Q of the battery 23 there is a certain correspondence between the remaining capacity ratio Q of the battery 23 and the open circuit voltage U.
  • the value of the remaining capacity ratio Q is also correspondingly determined. For example, when the open circuit voltage U is 3.6V, the remaining capacity ratio Q is 100%. When the open circuit voltage U is 3.3V, the remaining capacity ratio Q is 80%.
  • the remaining capacity ratio Q refers to the percentage of the remaining capacity of the battery 23 to the rated capacity. It can be understood that, in the embodiment of the present application, the sum of the value of the remaining capacity ratio Q of the battery 23 and the value of the discharge capacity ratio is 100%.
  • the corresponding relationship between the remaining capacity ratio Q and the open circuit voltage U can be determined according to the design requirements of the battery 23 .
  • the corresponding relationship between the remaining capacity ratio Q and the open circuit voltage U can be preset.
  • the corresponding relationship between the remaining capacity ratio Q and the open circuit voltage U is a positive correlation.
  • the battery device 20 determines the first remaining capacity ratio Q 1 corresponding to the first voltage value U 1 according to the parameter correspondence of the battery 23 .
  • the corresponding parameter relationship refers to the corresponding relationship between the remaining capacity ratio Q and the open circuit voltage U.
  • the first voltage value U 1 , the second voltage value U 2 , the third voltage value U 3 and the fourth voltage value U 4 described below are the open circuit voltage values of the battery 23 .
  • the battery discharge and undervoltage protection method may further include the following steps:
  • the full charge capacity means that the state of charge (State of Charge, SOC) of the battery 23 is 100%.
  • the battery device 20 can charge the battery 23 in a constant-current charging (Constant-Current Charging, CC) method, or can use a constant-voltage charging (Constant-Voltage Charging, CV) method to charge the battery 23.
  • the battery 23 is charged, or the battery 23 is charged in a constant current constant voltage (CC-CV) manner. It can be understood that the present application does not limit the charging method of the battery 23 .
  • the battery device 20 collects the voltage value of the battery 23 , the voltage value is the full charge voltage value.
  • a preset charging rate for example, 0.05C
  • the discharge cut-off voltage refers to a voltage at which the battery 23 stops discharging to prevent the battery 23 from being over-discharged.
  • the discharge cut-off voltage can be determined according to the design requirements of the battery 23 .
  • the preset discharge cut-off voltage is 2.8V.
  • the preset discharge cut-off voltage is 2.1V.
  • the battery device 20 can discharge the battery 23 at a preset discharge rate (for example, 0.3C, 0.5C or 1.0C, etc.). It can be understood that the present application does not limit the value of the preset discharge rate.
  • a preset discharge rate for example, 0.3C, 0.5C or 1.0C, etc.
  • the battery device 20 can collect the voltage value of the battery 23 and the state of charge (SOC) corresponding to the voltage value in real time through the battery management system. ).
  • the value of the state of charge (SOC) is equal to the value of the remaining capacity ratio Q.
  • S45 Determine the parameter correspondence of the battery 23 according to the voltage value and the state of charge (SOC) corresponding to the voltage value.
  • the parameter correspondence refers to the correspondence between the remaining capacity ratio Q and the open circuit voltage U.
  • the battery device 20 can fit the open circuit voltage and charge of the battery 23 according to the voltage value of the battery 23 during the discharge process and the state of charge (SOC) corresponding to the voltage value.
  • SOC state of charge
  • the characteristic curve of the open circuit voltage U and the remaining capacity ratio Q of the battery 23 (that is, the corresponding relationship of the parameters) is the same as the characteristic curve of the open circuit voltage and the state of charge (OCV-SOC).
  • steps S41-S45 are specific steps in an embodiment of obtaining the corresponding relationship of the parameters of the battery 23 .
  • the first undervoltage threshold U0 is a preset undervoltage threshold (such as 2.8V, 2.9V or 3.0V, etc.)
  • the second undervoltage threshold Ue is a dynamically adjusted undervoltage threshold voltage threshold (such as 2.1V, 2.2V or 2.4V, etc.).
  • step S34 may include the following sub-steps:
  • the battery device 20 may determine the second remaining capacity ratio Q 2 of the battery 23 according to the first remaining capacity ratio Q 1 and the discharge depth.
  • step S341 may include the following sub-steps:
  • the sum of the first remaining capacity ratio Q1 and the first discharge capacity ratio is 100%.
  • the first discharge capacity ratio can be calculated as (100%-Q 1 ).
  • the first discharge capacity ratio is less than the discharge depth (i.e. 100%-Q 1 ⁇ DOD x )
  • the current temperature value makes the discharge capacity ratio of the battery 23 decrease
  • the second remaining capacity ratio Q 2 100%-DOD x .
  • it is necessary to reduce the first undervoltage threshold U 0 that is, adjust the first undervoltage threshold U 0 to the second undervoltage threshold U e , so as to increase the discharge capacity ratio of the battery 23 .
  • the first discharge capacity ratio Q1 of the battery 23 decreases compared with the preset depth of discharge DODx . That is to say, the battery 23 loses a part of the discharge capacity ratio at low temperature, that is, DOD x ⁇ (100% ⁇ Q 1 ). To increase the discharge capacity ratio of the battery 23 at low temperature, it is necessary to reduce the first undervoltage threshold U0 to compensate for the discharge capacity ratio lost by the battery 23 at low temperature.
  • the battery 23 can discharge more capacity.
  • the battery device 20 may determine the second voltage value U 2 corresponding to the second remaining capacity ratio Q 2 according to the parameter correspondence of the battery 23 .
  • the first discharge capacity ratio is smaller than the discharge depth (ie 100%-Q 1 ⁇ DOD x )
  • the first remaining capacity ratio Q 1 is greater than the second remaining capacity ratio Q 2 (ie Q 1 >Q 2 ).
  • the first voltage value U 1 is greater than the second voltage value U 2 (ie U 1 >U 2 ).
  • the variation of the voltage value of the battery 23 ⁇ U U 1 ⁇ U 2 . It can be understood that the variation ⁇ U of the voltage value is caused by the low temperature of the battery 23 .
  • the second under-voltage threshold U e U 0 - ⁇ U.
  • FIG. 7 is a flow chart of a battery discharge undervoltage protection method in an embodiment. Assuming that the discharge rate is 0.3C, the temperature of the battery 23 is -10°C, the first voltage is 3.25V, and the preset first undervoltage threshold is 2.8V.
  • the battery discharge undervoltage protection method includes the following steps:
  • the discharge depth corresponding to the temperature range -10° C. to 0° C. is 80%.
  • the corresponding relationship between the open circuit voltage and the remaining capacity ratio is a positive correlation. According to the preset characteristic curve of the open circuit voltage and the remaining capacity ratio, it can be determined that the first remaining capacity ratio corresponding to the first voltage value of 3.25V is 30%.
  • the sum of the first remaining capacity ratio and the first discharge capacity ratio is 100%.
  • the discharge capacity ratio of the battery 23 decreases at low temperature.
  • the discharge capacity ratio of the battery 23 is reduced by 10% at a low temperature of -10°C.
  • the sum of the depth of discharge and the second remaining capacity ratio is 100%.
  • the second voltage value corresponding to the second remaining capacity ratio of 20% is 3.15V.
  • the second undervoltage threshold is calculated to be 2.7V.
  • the capacity ratio of the battery 23 that can continue to discharge is 10%, and the battery 23 can be compensated at -10
  • the discharge capacity loss ratio at low temperature is 10%.
  • steps S71-S78 are specific steps in an embodiment of determining the undervoltage threshold that the battery 23 needs to adjust at a low temperature of -10°C.
  • Each parameter value in the above steps S71-S78 is an exemplary value. That is to say, in other scenarios, with different preset parameter values, the parameter values measured by the battery device 20 and the calculated parameter values will also be correspondingly different. In other implementation manners, determining the dynamically adjusted under-voltage threshold may depend on specific application scenarios.
  • FIG. 8 shows the open circuit voltage curves of the battery 23 under different working conditions.
  • the working state includes a resting state, a charging state and a discharging state.
  • the full charging voltage and the charging cut-off voltage can be determined.
  • the discharge cut-off voltage can be determined according to the open circuit voltage curve of the battery 23 in the discharge state, and the discharge cut-off voltage is the first undervoltage threshold U 0 or the second undervoltage threshold U e . From the open-circuit voltage curve of the battery 23 at rest, it can be seen that the depth of discharge of the battery 23 changes from the full charge voltage to the full discharge.
  • the battery device 20 can preset the second undervoltage threshold U e in different temperature ranges, so as to select different undervoltage thresholds in different temperature ranges, so as to realize the adjustment of the undervoltage threshold dynamic adjustment.
  • Table 2 shows the ratio of the undervoltage threshold to the discharge capacity of the battery 23 at different temperature ranges.
  • the battery 23 is charged at the same temperature (eg 25° C.) with the same charge rate (eg 0.3 C). Then, the battery 23 is discharged at the same discharge rate (for example, 0.3C) and at different temperatures until the voltage of the battery 23 reaches the discharge cut-off voltage.
  • Divide temperature ranges for example, the first temperature range is 15°C to 45°C, the second temperature range is 0°C to 15°C, the third temperature range is -10°C to 0°C, and the fourth temperature range is -20°C to - 10°C.
  • the battery The discharge capacity ratio of the battery 23 is increased from 30% to 70%, which greatly improves the discharge performance of the battery 23 at low temperature.
  • the battery discharge and undervoltage protection method may further include the following steps:
  • the battery device 20 may collect the third voltage value U 3 through the battery management system. After the battery 23 is cut off for discharge, there are the following two situations:
  • the third voltage value U 3 of the battery 23 is greater than the second undervoltage threshold U e (that is, U 3 >U e ), that is, the third voltage value U 3 has not reached the discharge cut-off voltage (that is, the The second undervoltage threshold U e ). At this time, the battery 23 can continue to discharge, and of course there is no need to perform undervoltage protection on the battery 23 .
  • step S35 will be described below with a specific application scenario.
  • the adjusted second undervoltage threshold is determined to be 2.2V, that is, the discharge cut-off voltage is 2.2V.
  • the third voltage value collected by the battery management system is 2.3V
  • the third voltage value of 2.3V is greater than the discharge cut-off voltage of 2.2V, indicating that the voltage of the battery 23 has not yet reached the discharge threshold.
  • the cut-off voltage is 2.2V
  • the battery 23 can continue to discharge, that is, no undervoltage protection is required for the battery 23 .
  • the third voltage value collected by the battery management system is 2.2V
  • the third voltage value of 2.2V is equal to the discharge cut-off voltage of 2.2V
  • the capacity of the battery 23 may be irreversibly lost .
  • the third voltage value U3 changes dynamically, and the third voltage value U3 does not become stable until after a period of time.
  • the third voltage value U3 becoming stable means that the rate of change of the third voltage value U3 approaches zero within a preset time period.
  • the third voltage value U 3 that tends to be stable is defined as the fourth voltage value U 4 .
  • the fourth voltage value U 4 is greater than the second undervoltage threshold U e (that is, U 4 >U e ), the battery 23 continues to be discharged. If the fourth voltage value U 4 is smaller than the second undervoltage threshold U e (that is, U 4 ⁇ U e ), it is determined to perform undervoltage protection on the battery 23 .
  • FIG. 9 shows the open circuit voltage curves of the battery 23 at different temperatures after discharge.
  • S91 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 45°C.
  • S92 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 25°C.
  • S93 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 15°C.
  • S94 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at 0°C.
  • S95 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at -10°C.
  • S96 is the curve of the discharge rate at 0.3C and the ratio of voltage to discharge capacity at -20°C.
  • the dotted line part shows a rebound tendency of the voltage.
  • the battery 23 is discharged at the same discharge rate (for example, 0.3C) and at different temperatures. Hence, under the same discharge rate, different temperature values correspond to different second undervoltage thresholds U e . As the temperature decreases, the second under-voltage threshold U e will decrease accordingly. When the temperature changes, the second under-voltage threshold U e needs to be dynamically adjusted.
  • the battery device 20 can automatically adjust the second under-voltage threshold U e through the battery management system. For example, when the temperature value drops from -10°C to -20°C, the battery management system adjusts the second undervoltage threshold U e from 2.2V to 2.1V accordingly.

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Abstract

本申请公开了一种电池放电欠压保护方法、电池装置及用电装置，涉及电池技术领域。本申请一实施例的电池放电欠压保护方法包括：获取电池的温度值和第一电压值；根据温度值，确定电池的放电深度；根据第一电压值，确定电池的第一剩余容量比；根据第一剩余容量比、放电深度及第一欠压阈值，确定第二欠压阈值，以增大电池的放电容量比。本申请通过确定不同温度区间下的欠压阈值，在不同温度下选取不同的欠压阈值，从而实现对欠压阈值的动态调节，增大电池在低温下的放电容量比。

Description

电池放电欠压保护方法、电池装置及用电装置 技术领域
本申请涉及电池技术领域，具体涉及一种电池放电欠压保护方法、电池装置及用电装置。
背景技术
目前，针对电池的欠压保护控制，通常采用设置固定欠压保护点的方式，固定欠压保护点设置在2.8V～3.0V范围内，通用的保护点为：一级欠压告警：3.0V，二级欠压保护：2.9V；三级欠压保护：2.8V。然而，当电池在低温条件下进行放电时，电池的放电容量比将急剧减小，无法满足电池在低温下的容量需求。
发明内容
鉴于此，本申请提供一种电池放电欠压保护方法、电池装置及用电装置，可以解决电池在低温下放电容量比减小的问题。
本申请一实施例的电池放电欠压保护方法包括：获取电池的温度值和第一电压值；根据所述温度值，确定所述电池的放电深度；根据所述第一电压值，确定所述电池的第一剩余容量比；根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值，以增大所述电池的放电容量比；其中，所述第一欠压阈值为预设欠压阈值，所述第二欠压阈值为动态调节后的欠压阈值。
在其中一种实施方式中，所述根据所述温度值，确定所述电池的放电深度，包括：确定所述温度值对应的温度区间；根据所述温度区间，确定所述温度区间对应的所述放电深度。
在另一种实施方式中，所述根据所述第一电压值，确定所述电池的第一剩余容量比，包括：根据所述电池的参数对应关系，确定所述第一电压值对应的所述第一剩余容量比；其中，所述参数对应关系是指剩余容量比与开路电压的对应关系。
在另一种实施方式中，所述根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值，包括：根据所述第一剩余容量比和所述放电深度，确定所述电池的第二剩余容量比；根据所述参数对应关系，确定所述第二剩余容量比对应的第二电压值；根据所述第二电压值和所述第一电压值，确定所述电池的电压值的变化量；根据所述电压值的变化量和所述第一欠压阈值，确定所述第二欠压阈值。
在另一种实施方式中，在所述根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值之后，所述方法还包括：获取所述电池在截止放电后的第三电压值；根据所述第二欠压阈值和所述第三电压值，确定是否对所述电池进行欠压保护。
在另一种实施方式中，所述根据所述第二欠压阈值和所述第三电压值，确定 是否对所述电池进行欠压保护，包括：根据所述第三电压值，确定第四电压值；若所述第四电压值小于所述第二欠压阈值，则确定对所述电池进行欠压保护。
在另一种实施方式中，在所述根据所述电池的参数对应关系，确定所述第一电压值对应的所述第一剩余容量比之前，所述方法还包括：对所述电池进行充电，直至所述电池的容量达到满充容量；获取所述满充容量对应的满充电压；对所述电池进行放电，直至所述电池的电压达到放电截止电压；获取所述电池在放电过程中的电压值和所述电压值对应的荷电状态；根据所述电压值和所述电压值对应的荷电状态，确定所述参数对应关系。
在另一种实施方式中，所述根据所述第一剩余容量比和所述放电深度，确定所述电池的第二剩余容量比，包括：根据所述第一剩余容量比，确定所述电池的第一放电容量比；根据所述第一放电容量比和所述放电深度，确定所述第二剩余容量比。
本申请另一实施例的电池装置包括电池、处理器及存储器，所述存储器中存储有计算机程序，当所述计算机程序被所述处理器执行时，实现本申请实施例的电池放电欠压保护方法。
本申请另一实施例的用电装置包括负载及本申请实施例的电池装置，所述电池装置用于为所述负载提供电能。
在其中一种实施方式中，所述用电装置包括无人机、电动车、电动工具及储能产品中的任一种。
本申请实施例通过电池的温度值、第一电压值及第一欠压阈值，确定第二欠压阈值，进而确定不同温度区间下的欠压阈值，以在不同温度区间下选取不同的欠压阈值，从而实现对欠压阈值的动态调节，增大所述电池在低温下的放电容量比。而且，本申请实施例根据所述电池在截止放电后的第三电压和所述第二欠压阈值来确定是否对电池进行欠压保护，能够避免过早地对所述电池进行欠压保护，保证所述电池在低温下的放电容量比。
附图说明
图1是电池在不同温度下的电压与放电容量比的曲线图。
图2是本申请一实施方式的电池装置的方框图。
图3是本申请一实施方式的电池放电欠压保护方法的流程图。
图4是本申请另一实施方式的电池放电欠压保护方法的流程图。
图5是本申请另一实施方式的电池放电欠压保护方法的流程图。
图6为本申请另一实施方式的电池放电欠压保护方法的流程图。
图7为本申请另一实施方式的电池放电欠压保护方法的流程图。
图8是电池在不同工作状态下的开路电压曲线。
图9是电池截止放电后在不同温度下的开路电压曲线。
主要元件符号说明
10                   用电装置
11                   负载
20                   电池装置
21                   存储器
22                   处理器
23                   电池
24                   传感器
具体实施方式
为了能够更清楚地理解本申请的上述目的、特征和优点，下面结合附图和具体实施例对本申请进行详细描述。需要说明的是，在不冲突的情况下，本申请的实施例及实施例中的特征可以相互组合。在下面的描述中阐述了很多具体细节以便于充分理解本申请，所描述的实施例仅是本申请一部分实施例，而不是全部的实施例。
需要说明的是，虽然在流程图中示出了逻辑顺序，但是在某些情况下，可以以不同于流程图中的顺序执行所示出或描述的步骤。本申请实施例中公开的方法包括用于实现方法的一个或多个步骤或动作。方法步骤和/或动作可以在不脱离权利要求的范围的情况下彼此互换。换句话说，除非指定步骤或动作的特定顺序，否则特定步骤和/或动作的顺序和/或使用可以在不脱离权利要求范围的情况下被修改。
图1为电池在不同温度下的电压与放电容量比的曲线图。其中，S11是0.3C放电倍率及45℃下电压与放电容量比的曲线。S12是0.3C放电倍率及25℃下电压与放电容量比的曲线。S13是0.3C放电倍率及15℃下电压与放电容量比的曲线。S14是0.3C放电倍率及0℃下电压与放电容量比的曲线。S15是0.3C放电倍率及-10℃下电压与放电容量比的曲线。S16是0.3C放电倍率及-20℃下电压与放电容量比的曲线。
如图1所示，在相同的放电倍率(例如0.3C)下，电池在不同温度下的放电容量比均不同。随着温度降低，电池的放电容量比将会急剧下降。
在本申请实施例中，温度是指环境温度，电池在不同温度下是指电池处于不同的环境温度。
在本申请实施例中，电压是指电池的开路电压(Open Circuit Voltage，OCV)，即电池在开路状态下的端电压。
在本申请实施例中，放电容量比是指电池放出的容量占额定容量的百分比。
表1为电池在不同温度下的放电容量比的情况。请一并参阅图1与表1，首先，在相同的温度(例如25℃)下，采用相同的充电倍率(例如0.3C)对电池进行充电。然后，在相同的放电倍率(例如0.3C)及不同温度下对所述电池进行放电，直至所述电池的电压达到放电截止电压(例如2.5V)。最后，确定所述电池的放电容量比。由表1可知，随着温度降低，所述电池的放电容量比将会急剧下降。
表1 电池在不同温度下的放电容量比
Figure PCTCN2021095187-appb-000001
由于电池在低温下的放电容量比会急剧减小，造成电池在低温下的放电容量无法满足需求。
基于此，本申请提供一种电池放电欠压保护方法、电池装置及用电装置，能够增大电池在低温下的放电容量比。
图2为电池装置20的方框图。如图2所示，所述电池装置20包括存储器21、处理器22、电池23及传感器24，上述元件之间可以通过总线连接，也可以直接连接。
所述存储器21用于存储程序代码和各种数据，并在电池装置20的运行过程中完成程序或数据的存取。所述存储器21可以是电池装置20的内部存储器，即内置于所述电池装置20的存储器。在其它实施方式中，所述存储器21也可以是电池装置20的外部存储器，即外接于所述电池装置20的存储器。
所述存储器21包括易失性或非易失性存储器件，例如数字通用光盘(Digital Versatile Disc，DVD)或其它光盘、磁盘、硬盘、智能存储卡(Smart Media Card，SMC)、安全数字(Secure Digital，SD)卡、闪存卡(Flash Card)等。
所述处理器22包括中央处理单元(Central Processing Unit，CPU)、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit，ASIC)、现场可编程门阵列(Field-Programmable Gate Array，FPGA)或者其它可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。
在其中一种实施方式中，所述电池23为可充电电池，用以给所述电池装置20提供电能。例如，所述电池23可以是铅酸电池、镍镉电池、镍氢电池、锂离子电池、锂聚合物电池及磷酸铁锂电池等。所述电池23包括电芯。所述传感器 24可设置于所述电芯的表面，通过测量电芯表面的温度，以获取环境温度。在其中一种实施方式中，所述传感器24为负温度系数(Negative Temperature Coefficient，NTC)热敏电阻。可以理解，所述电池装置20还可以包括其它传感器，例如电压传感器、电流传感器、光线传感器、陀螺仪、湿度计、红外线传感器等。
可以理解，电池装置20也可以包括更多或者更少的元件，或者具有不同的元件配置。所述电池装置20可应用于用电装置10，所述用电装置10包括，但不限于，无人机、电动车、电动工具、储能产品等。所述电动工具包括，但不限于，电动螺丝刀、电钻、电动扳手、角磨机、钢材机、电镐、电锤、云石机、曲线锯等。所述储能产品包括，但不限于，手机、平板电脑、电子书阅读器、计算机、工作站、服务器、个人数字助理(Personal Digital Assistant，PDA)、便携式多媒体播放器(Portable Multimedia Player，PMP)、移动医疗设备、相机、可穿戴设备、光伏逆变器、风电变流器、储能***、新能源汽车驱动***、光伏设备等。
在其中一种实施方式中，所述用电装置10包括所述电池装置20和负载11，所述电池装置20用于为所述负载11提供电能。
所述负载11包括，但不限于，冰箱、冷饮机、空调器、电扇、换气扇、冷热风器、空气去湿器、洗衣机、干衣机、电熨斗、吸尘器、地板打蜡机、微波炉、电磁灶、电烤箱、电饭锅、洗碟机、电热水器、电热毯、电热被、电热服、空间加热器、电动剃须刀、电吹风、整发器、超声波洗面器、电动按摩器、微型投影仪、电视机、收音机、录音机、录像机、摄像机、组合音响、烟火报警器、电铃、电灯、电脑等。
在其中一种实施方式中，电池装置20还包括电池管理***(Battery Management System，BMS)。所述电池23通过所述电池管理***与所述处理器22连接，从而通过所述电池管理***实现充电、放电及功耗管理等功能。电池管理***可与储能变流器(Power Conversion System，PCS)通讯连接。
图3为一实施方式的电池放电欠压保护方法的流程图。所述电池放电欠压保护方法包括如下步骤：
S31，获取所述电池23的温度值和第一电压值U 1。
在本实施例中，所述电池23的温度值是指所述电池23所处环境的温度值。当所述电池23处于静置状态时，采集所述电池23的温度值和第一电压值U 1。所述静置状态是指所述电池23的充电或放电电流趋近于0A的状态。在其中一种实施方式中，将所述电池23的充电或放电电流小于0.5A的状态定义为静置状态。
具体地，所述电池装置20通过所述传感器24来获取所述电池23的温度值(例如-20℃～50℃中任一温度值)。所述电池装置20通过电池管理***来获取所述电池23的第一电压值U 1(例如2.0V～3.6V中任一电压值)。
在本实施例中，所述电池装置20可以实时地获取所述电池23的温度值和第一电压值U 1，或者按照预设时间间隔(例如1s或2s等)获取所述电池23的 温度值和第一电压值U 1。所述预设时间间隔可依具体需求而定。
S32，根据所述温度值，确定所述电池23的放电深度(Depth Of Discharge，DOD)。
在本实施例中，放电深度(DOD)是指电池23放出的容量占额定容量的百分比。可以理解，在本申请实施例中，电池23的放电深度的取值等于放电容量比的取值。
在其中一种实施方式中，所述电池装置20根据采集到的所述温度值，确定所述温度值对应的温度区间。可以理解，所述放电深度与所述温度区间存在一定的对应关系。当所述电池23处于不同的温度区间时，所述放电深度也相应不同。当所述温度区间被确定时，所述放电深度也相应被确定。例如，当所述温度区间为15℃～45℃，所述放电深度为95％。当所述温度区间为-20℃～-10℃，所述放电深度为70％。
可以理解，所述放电深度与所述温度区间的对应关系可依所述电池23的设计需求而定。例如，在电池23设计之初，可预设所述电池23在不同温度区间下的放电深度。
S33，根据所述第一电压值U 1，确定所述电池23的第一剩余容量比Q 1。
在本实施例中，电池23的剩余容量比Q与开路电压U存在一定的对应关系。当所述开路电压U的取值被确定时，所述剩余容量比Q的取值也相应被确定。例如，当所述开路电压U为3.6V时，所述剩余容量比Q为100％。当所述开路电压U为3.3V时，所述剩余容量比Q为80％。
在本实施例中，剩余容量比Q是指电池23的剩余容量占额定容量的百分比。可以理解，在本申请实施例中，电池23的剩余容量比Q的取值与放电容量比的取值之和为100％。
可以理解，所述剩余容量比Q与开路电压U的对应关系可依所述电池23的设计需求而定。例如，在电池23设计之初，可预设所述剩余容量比Q与开路电压U的对应关系。在其中一种实施方式中，所述剩余容量比Q与开路电压U的对应关系为正相关关系。
在其中一种实施方式中，所述电池装置20根据所述电池23的参数对应关系，确定所述第一电压值U 1对应的所述第一剩余容量比Q 1。其中，所述参数对应关系是指剩余容量比Q与开路电压U的对应关系。
在本申请实施例中，所述第一电压值U 1，以及下文记载的第二电压值U 2、第三电压值U 3和第四电压值U 4均为所述电池23的开路电压值。
在其中一种实施方式中，请参阅图4，在步骤S33之前，所述电池放电欠压保护方法还可以包括如下步骤：
S41，对所述电池23进行充电，直至所述电池23的容量达到满充容量。
在本实施例中，满充容量是指所述电池23的荷电状态(State of Charge，SOC)为100％。
在本实施例中，所述电池装置20可以采用恒流充电(Constant-Current Charging，CC)方式对所述电池23进行充电，也可以采用恒压充电(Constant- Voltage Charging，CV)方式对所述电池23进行充电，或者采用恒流恒压充电(CC-CV)方式对所述电池23进行充电。可以理解，本申请并不限制所述电池23的充电方式。
S42，获取所述满充容量对应的满充电压。
在本实施例中，当充电电流不超过一预设充电倍率(例如0.05C)，且所述电池23的容量达到所述满充容量时，所述电池装置20采集所述电池23的电压值，所述电压值即为满充电压值。
S43，对所述电池23进行放电，直至所述电池23的电压达到放电截止电压。
在本实施例中，所述放电截止电压是指为防止所述电池23过度放电，使得所述电池23停止放电的电压。
可以理解，所述放电截止电压可依所述电池23的设计需求而定。例如，当所述温度区间为15℃～45℃，预设所述放电截止电压为2.8V。当所述温度区间为-20℃～-10℃，预设所述放电截止电压为2.1V。
在本实施例中，所述电池装置20可以通过一预设放电倍率(例如0.3C、0.5C或1.0C等)对所述电池23进行放电。可以理解，本申请并不限制所述预设放电倍率的取值。
S44，获取所述电池23在放电过程中的电压值和所述电压值对应的荷电状态(SOC)。
在本实施例中，当对所述电池23进行放电时，所述电池装置20可以通过所述电池管理***来实时采集所述电池23的电压值和所述电压值对应的荷电状态(SOC)。所述荷电状态(SOC)的取值等于剩余容量比Q的取值。
S45，根据所述电压值和所述电压值对应的荷电状态(SOC)，确定所述电池23的参数对应关系。
在本实施例中，所述参数对应关系是指剩余容量比Q与开路电压U的对应关系。
在本实施例中，所述电池装置20可以根据所述电池23在放电过程中的电压值和所述电压值对应的荷电状态(SOC)，拟合出所述电池23的开路电压与荷电状态(OCV-SOC)的特性曲线。
可以理解，所述电池23的开路电压U与剩余容量比Q的特征曲线(即所述参数对应关系)，与所述开路电压与荷电状态(OCV-SOC)的特性曲线相同。
可以理解，上述步骤S41-S45为获取所述电池23的参数对应关系的一实施方式的具体步骤。
S34，根据所述第一剩余容量比Q 1、所述放电深度及第一欠压阈值U 0，确定第二欠压阈值U e。
在本申请实施例中，所述第一欠压阈值U 0为预设欠压阈值(例如2.8V、2.9V或3.0V等)，所述第二欠压阈值U e为动态调节后的欠压阈值(例如2.1V、2.2V或2.4V等)。
在其中一种实施方式中，请参阅图5，步骤S34可以包括如下子步骤：
S341，根据所述第一剩余容量比Q 1和所述放电深度，确定所述电池23的 第二剩余容量比Q 2。
在本实施例中，所述电池装置20可以根据所述第一剩余容量比Q 1和所述放电深度，确定所述电池23的第二剩余容量比Q 2。
在其中一种实施方式中，请参阅图6，步骤S341可以包括如下子步骤：
S3411，根据所述第一剩余容量比Q 1，确定所述电池23的第一放电容量比。
在本实施例中，所述第一剩余容量比Q 1与所述第一放电容量比之和为100％。根据所述第一剩余容量比Q 1，计算可得所述第一放电容量比为(100％-Q 1)。
S3412，根据所述第一放电容量比和所述放电深度，确定所述第二剩余容量比Q 2。
在本实施例中，预设所述放电深度为DOD x，当所述第一放电容量比等于所述放电深度(即100％-Q 1＝DOD x)时，说明当前的温度值不影响所述电池23的放电容量比，所述第二剩余容量比Q 2等于所述第一剩余容量比Q 1(即Q 2＝Q 1)。此时，不需要调整所述第一欠压阈值U 0。
当所述第一放电容量比小于所述放电深度(即100％-Q 1<DOD x)时，说明当前的温度值使得所述电池23的放电容量比减小，所述第二剩余容量比Q 2＝100％-DOD x。此时，需要调小所述第一欠压阈值U 0，即将所述第一欠压阈值U 0调节为所述第二欠压阈值U e，以增大所述电池23的放电容量比。
可以理解，由于低温影响，所述电池23的第一放电容量比Q 1相较于预设的所述放电深度DOD x减小。也就是说，所述电池23在低温下损失了一部分的放电容量比，即DOD x-(100％-Q 1)。若要增大所述电池23在低温下的放电容量比，则需要通过调小所述第一欠压阈值U 0来补偿所述电池23在低温下损失的放电容量比。
可以理解，当调小所述第一欠压阈值U 0(即调小放电截止电压)时，所述电池23可以放出更多的容量。
S342，根据所述参数对应关系，确定所述第二剩余容量比Q 2对应的第二电压值U 2。
在本实施例中，所述电池装置20可以根据所述电池23的参数对应关系，确定所述第二剩余容量比Q 2对应的第二电压值U 2。
可以理解，当所述第一放电容量比小于所述放电深度(即100％-Q 1<DOD x)时，所述第一剩余容量比Q 1大于所述第二剩余容量比Q 2(即Q 1>Q 2)。相应地，所述第一电压值U 1大于所述第二电压值U 2(即U 1>U 2)。
S343，根据所述第二电压值U 2和所述第一电压值U 1，确定所述电池23的电压值的变化量ΔU。
在本实施例中，所述电池23的电压值的变化量ΔU＝U 1-U 2。可以理解，所述电压值的变化量ΔU是由所述电池23受低温影响而导致的。
S344，根据所述电压值的变化量ΔU和所述第一欠压阈值U 0，确定所述第二欠压阈值U e。
在本实施例中，为补偿所述电池23在低温下损失的放电容量比(即DOD x-(100％-Q 1))，所述第二欠压阈值U e＝U 0-ΔU。
可以理解，当将所述第一欠压阈值U 0调节为所述第二欠压阈值U e＝U 0-ΔU时，所述电池23可继续放电的容量比为DOD x-(100％-Q 1)。
请参阅图7，图7为一实施方式的电池放电欠压保护方法的流程图。假设放电倍率为0.3C，所述电池23的温度值为-10℃，第一电压值为3.25V，预设的第一欠压阈值为2.8V。
可以理解，当所述放电倍率的取值不同时，所述第一欠压阈值的取值也应做相应调整。
所述电池放电欠压保护方法包括如下步骤：
S71，根据预设的温度区间与放电深度的对应关系，确定温度值-10℃对应的放电深度为80％。
在本实施例中，根据预设的温度区间与放电深度的对应关系，温度区间-10℃～0℃对应的放电深度均为80％。
S72，根据预设的开路电压与剩余容量比的对应关系，确定第一电压值3.25V对应的第一剩余容量比为30％。
在本实施例中，开路电压与剩余容量比的对应关系为正相关关系。根据预设的开路电压与剩余容量比的特性曲线，可确定第一电压值3.25V对应的第一剩余容量比为30％。
S73，根据所述第一剩余容量比30％，计算得到第一放电容量比为70％。
在本实施例中，所述第一剩余容量比与所述第一放电容量比之和为100％。
S74，根据所述放电深度80％和所述第一放电容量比70％，计算得到所述电池23在-10℃低温下损失的放电容量比为10％。
可以理解，所述电池23在低温下的放电容量比减小。在本实施例中，所述电池23在-10℃低温下的放电容量比减小了10％。
S75，根据所述放电深度80％，计算得到第二剩余容量比为20％。
在本实施例中，所述放电深度与所述第二剩余容量比之和为100％。
S76，根据预设的开路电压与剩余容量比的对应关系，确定所述第二剩余容量比20％对应的第二电压值为3.15V。
在本实施例中，根据预设的开路电压与剩余容量比的特性曲线，可确定所述第二剩余容量比20％对应的第二电压值为3.15V。
S77，根据所述第一电压值3.25V和所述第二电压值为3.15V，计算得到所述电池23在-10℃低温下产生的电压值的变化量为0.1V。
可以理解，所述电池23在-10℃低温下产生的电压值的变化量0.1V与损失的放电容量比10％相对应。
S78，根据所述第一欠压阈值2.8V和所述电池23在-10℃低温下产生的电压值的变化量0.1V，计算得到第二欠压阈值为2.7V。
可以理解，当将所述第一欠压阈值2.8V调节至所述第二欠压阈值2.7V时，所述电池23可继续放电的容量比为10％，可补偿所述电池23在-10℃低温下损失的放电容量比10％。
可以理解，上述步骤S71-S78为确定所述电池23在-10℃低温下所需调节的 欠压阈值的一实施方式的具体步骤。上述步骤S71-S78中的各个参数值均为示例性的取值。也就是说，在其它场景下，随预设的各个参数值不同，所述电池装置20测得的参数值和计算得到的参数值也会相应不同。在其它实施方式中，确定动态调节后的欠压阈值可依具体应用场景而定。
请参阅图8，图8为所述电池23在不同工作状态下的开路电压曲线。所述工作状态包括静置状态、充电状态及放电状态。根据所述电池23在充电状态下的开路电压曲线可以确定满充电压与充电截止电压。根据所述电池23在放电状态下的开路电压曲线可以确定放电截止电压，所述放电截止电压即为所述第一欠压阈值U 0或所述第二欠压阈值U e。从所述电池23在静置状态下的开路电压曲线可以看出，所述电池23从所述满充电压到完全放电时的放电深度变化。从所述电池23在放电状态下的开路电压曲线可以看出，所述电池23从所述充电截止电压到所述放电截止电压的放电深度变化，以及截止放电后的电压变化。显然，通过减小所述放电截止电压，所述电池23的放电深度会相应增大，所述电池23的放电容量比也会相应增大。
在其中一种实施方式中，所述电池装置20可以预设不同温度区间下的所述第二欠压阈值U e，以在不同温度区间下选取不同的欠压阈值，从而实现对欠压阈值的动态调节。
表2为所述电池23在不同温度区间下的欠压阈值与放电容量比的情况。首先，在相同的温度(例如25℃)下，采用相同的充电倍率(例如0.3C)对所述电池23进行充电。然后，在相同的放电倍率(例如0.3C)及不同温度下对所述电池23进行放电，直至所述电池23的电压达到放电截止电压。划分温度区间，例如，第一温度区间为15℃～45℃，第二温度区间为0℃～15℃，第三温度区间为-10℃～0℃，第四温度区间为-20℃～-10℃。最后，确定所述电池23在不同温度区间和所述第一欠压阈值(例如2.8V)下的放电容量比，以及所述电池23在不同温度区间和所述第二欠压阈值(例如2.8V、2.4V、2.2V、2.1V等)下的放电容量比。由表2可知，在0℃以下，相较于所述电池23在所述第一欠压阈值(即预设欠压阈值)下的放电容量比，所述电池23在所述第二欠压阈值(即动态调节后的欠压阈值)下的放电容量比显著增大，说明将所述第一欠压阈值调节为所述第二欠压阈值，可以明显地改善所述电池23在低温下的放电性能。例如，在-20℃～-10℃的所述第四温度区间，将所述第一欠压阈值(即2.8V)调节为所述第二欠压阈值(即2.1V)之后，所述电池23的放电容量比从30％增大到70％，极大地改善了所述电池23在低温下的放电性能。
表2 电池23在不同温度区间下的欠压阈值与放电容量比的情况
Figure PCTCN2021095187-appb-000002
在其中一种实施方式中，在步骤S34之后，所述电池放电欠压保护方法还可以包括如下步骤：
S35，根据所述电池23在截止放电后的第三电压值U 3和所述第二欠压阈值U e，确定是否对所述电池23进行欠压保护。
可以理解，所述电池装置20可以通过所述电池管理***来采集所述第三电压值U 3。当所述电池23截止放电之后，存在以下两种情形：
(1)所述电池23的第三电压值U 3大于所述第二欠压阈值U e(即U 3>U e)，即所述第三电压值U 3未达到放电截止电压(即所述第二欠压阈值U e)。此时，所述电池23可以继续放电，当然也就不需要对所述电池23进行欠压保护。
(2)所述电池23的第三电压值U 3等于所述第二欠压阈值U e(即U 3＝U e)，即所述第三电压值U 3达到所述放电截止电压(即所述第二欠压阈值U e)。若所述电池23继续放电，可能造成所述电池23的容量发生不可逆地损失。此时，需要对所述电池23进行欠压保护。
以下将以一具体应用场景对上述步骤S35进行描述。
假设所述电池23的温度值为-10℃，根据预设的第一欠压阈值2.8V，确定调整后的第二欠压阈值为2.2V，即放电截止电压为2.2V。
所述电池23在截止放电后，当所述电池管理***采集的第三电压值为2.3V时，第三电压值2.3V大于放电截止电压2.2V，说明所述电池23的电压还未达到放电截止电压2.2V，所述电池23可继续放电，即不需要对所述电池23进行欠压保护。
当所述电池管理***采集的第三电压值为2.2V时，第三电压值2.2V等于放电截止电压2.2V，若所述电池23继续放电，可能造成所述电池23的容量发生不可逆地损失。此时，需要对所述电池23进行欠压保护。
可以理解，所述电池23截止放电后，所述第三电压值U 3动态变化，直至一段时间后，所述第三电压值U 3才趋于稳定。在本实施例中，所述第三电压值U 3趋于稳定是指在预设时间段内，所述第三电压值U 3的变化率趋近于0。在本实施例中，将趋于稳定的所述第三电压值U 3定义为第四电压值U 4。
在其中一种实施方式中，根据所述电池23在截止放电后的第四电压值U 4和所述第二欠压阈值U e，确定是否对所述电池23进行欠压保护。
具体地，若所述第四电压值U 4大于所述第二欠压阈值U e(即U 4>U e)，则对所述电池23继续放电。若所述第四电压值U 4小于所述第二欠压阈值U e(即U 4<U e)，则确定对所述电池23进行欠压保护。
请参阅图9，图9为所述电池23截止放电后在不同温度下的开路电压曲线。其中，S91是0.3C放电倍率及45℃下电压与放电容量比的曲线。S92是0.3C放电倍率及25℃下电压与放电容量比的曲线。S93是0.3C放电倍率及15℃下电压与放电容量比的曲线。S94是0.3C放电倍率及0℃下电压与放电容量比的曲线。S95是0.3C放电倍率及-10℃下电压与放电容量比的曲线。S96是0.3C放电倍率及-20℃下电压与放电容量比的曲线。在曲线S93、S94、S95及S96中，当电压达到所述第二欠压阈值U e之后，虚线部分展示了电压的反弹趋势。
在相同的放电倍率(例如0.3C)及不同温度下对所述电池23进行放电。显然，在相同的放电倍率下，不同温度值对应的第二欠压阈值U e不同。随着温度降低，所述第二欠压阈值U e会相应减小。当温度发生变化时，需要动态调节所述第二欠压阈值U e。
在其中一种实施方式中，所述电池装置20可以通过所述电池管理***来自动调节所述第二欠压阈值U e。例如，当温度值从-10℃降低至-20℃时，所述电池管理***相应地将所述第二欠压阈值U e从2.2V调节为2.1V。
上面结合附图对本申请实施例作了详细说明，但是本申请不限于上述实施例，在所属技术领域普通技术人员所具备的知识范围内，还可以在不脱离本申请宗旨的前提下做出各种变化。此外，在不冲突的情况下，本申请的实施例及实施例中的特征可以相互组合。

Claims (11)

  1. 一种电池放电欠压保护方法，其特征在于，所述方法包括：
    获取电池的温度值和第一电压值；
    根据所述温度值，确定所述电池的放电深度；
    根据所述第一电压值，确定所述电池的第一剩余容量比；
    根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值，以增大所述电池的放电容量比；其中，所述第一欠压阈值为预设欠压阈值，所述第二欠压阈值为动态调节后的欠压阈值。
  2. 如权利要求1所述的电池放电欠压保护方法，其特征在于，所述根据所述温度值，确定所述电池的放电深度，包括：
    确定所述温度值对应的温度区间；
    根据所述温度区间，确定所述温度区间对应的所述放电深度。
  3. 如权利要求1所述的电池放电欠压保护方法，其特征在于，所述根据所述第一电压值，确定所述电池的第一剩余容量比，包括：
    根据所述电池的参数对应关系，确定所述第一电压值对应的所述第一剩余容量比；其中，所述参数对应关系是指剩余容量比与开路电压的对应关系。
  4. 如权利要求3所述的电池放电欠压保护方法，其特征在于，所述根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值，包括：
    根据所述第一剩余容量比和所述放电深度，确定所述电池的第二剩余容量比；
    根据所述参数对应关系，确定所述第二剩余容量比对应的第二电压值；
    根据所述第二电压值和所述第一电压值，确定所述电池的电压值的变化量；
    根据所述电压值的变化量和所述第一欠压阈值，确定所述第二欠压阈值。
  5. 如权利要求1至4任一项所述的电池放电欠压保护方法，其特征在于，在所述根据所述第一剩余容量比、所述放电深度及第一欠压阈值，确定第二欠压阈值之后，所述方法还包括：
    获取所述电池在截止放电后的第三电压值；
    根据所述第二欠压阈值和所述第三电压值，确定是否对所述电池进行欠压保护。
  6. 如权利要求5所述的电池放电欠压保护方法，其特征在于，所述根据所述第二欠压阈值和所述第三电压值，确定是否对所述电池进行欠压保护，包括：
    根据所述第三电压值，确定第四电压值；
    若所述第四电压值小于所述第二欠压阈值，则确定对所述电池进行欠压保护。
  7. 如权利要求3所述的电池放电欠压保护方法，其特征在于，在所述根据所述电池的参数对应关系，确定所述第一电压值对应的所述第一剩余容量比之前，所述方法还包括：
    对所述电池进行充电，直至所述电池的容量达到满充容量；
    获取所述满充容量对应的满充电压；
    对所述电池进行放电，直至所述电池的电压达到放电截止电压；
    获取所述电池在放电过程中的电压值和所述电压值对应的荷电状态；
    根据所述电压值和所述电压值对应的荷电状态，确定所述参数对应关系。
  8. 如权利要求4所述的电池放电欠压保护方法，其特征在于，所述根据所述第一剩余容量比和所述放电深度，确定所述电池的第二剩余容量比，包括：
    根据所述第一剩余容量比，确定所述电池的第一放电容量比；
    根据所述第一放电容量比和所述放电深度，确定所述第二剩余容量比。
  9. 一种电池装置，其特征在于，所述电池装置包括电池、处理器及存储器，所述存储器中存储有计算机程序，当所述计算机程序被所述处理器执行时，实现如权利要求1至8任一项所述的电池放电欠压保护方法。
  10. 一种用电装置，其特征在于，所述用电装置包括负载及如权利要求9所述的电池装置，所述电池装置用于为所述负载提供电能。
  11. 如权利要求10所述的用电装置，其特征在于，所述用电装置包括无人机、电动车、电动工具及储能产品中的任一种。
PCT/CN2021/095187 2021-05-21 2021-05-21 电池放电欠压保护方法、电池装置及用电装置 WO2022241766A1 (zh)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000100290A (ja) * 1998-09-26 2000-04-07 Uchihashi Estec Co Ltd 回路の保護方法及び抵抗体付き温度ヒュ−ズ
CN108279385A (zh) * 2018-01-26 2018-07-13 深圳市道通智能航空技术有限公司 电池的电量状态估算方法、装置及电子设备
CN111913111A (zh) * 2020-07-24 2020-11-10 蜂巢能源科技有限公司 放电功率校正方法、装置、存储介质及电子设备

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000100290A (ja) * 1998-09-26 2000-04-07 Uchihashi Estec Co Ltd 回路の保護方法及び抵抗体付き温度ヒュ−ズ
CN108279385A (zh) * 2018-01-26 2018-07-13 深圳市道通智能航空技术有限公司 电池的电量状态估算方法、装置及电子设备
CN111913111A (zh) * 2020-07-24 2020-11-10 蜂巢能源科技有限公司 放电功率校正方法、装置、存储介质及电子设备

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