WO2023159708A1 - 一种电池常带电自保养的控制方法及常带电自保养的电池 - Google Patents

一种电池常带电自保养的控制方法及常带电自保养的电池 Download PDF

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WO2023159708A1
WO2023159708A1 PCT/CN2022/082537 CN2022082537W WO2023159708A1 WO 2023159708 A1 WO2023159708 A1 WO 2023159708A1 CN 2022082537 W CN2022082537 W CN 2022082537W WO 2023159708 A1 WO2023159708 A1 WO 2023159708A1
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battery
power
self
charging
charged
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PCT/CN2022/082537
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English (en)
French (fr)
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刘智聪
黄志聪
汪振
陈国栋
林小龙
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深圳市涞顿科技有限公司
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Publication of WO2023159708A1 publication Critical patent/WO2023159708A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

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  • the invention relates to the technical field of mobile energy storage batteries, in particular to a control method for self-maintenance of batteries when they are always charged and a battery for self-maintenance when they are always charged.
  • the battery state of charge (stage of charge, SOC) is the ratio of the current remaining capacity of the battery to the actual available capacity of the battery.
  • SOC state of charge
  • Overcharge and overdischarge so as to prolong the service life of the battery and ensure the battery life market, its accurate estimation is the prerequisite for the realization of the main functions of the BMS.
  • the ampere-hour measurement method relying on current integration
  • the neural network method based on a large number of sample raw data and neural network models based on a large number of sample raw data and neural network models
  • the Kalman filter method based on the battery state space model and recursive formula, etc.
  • the ampere-hour measurement method has a simple principle, stable operation, easy implementation, low equipment cost, high reliability and economy, and has been widely used in practical engineering.
  • the accuracy of the traditional ampere-hour integration method depends on the estimation accuracy of the initial remaining power, and as the battery usage time increases, there will also be accumulated integration errors during the current time integration process, and the overall remaining power estimation accuracy will decrease with time. However, it gradually decreases, and there are problems such as gradual accumulation of remaining power estimation errors and continuous decline in accuracy. Incorrect estimation of the remaining power will lead to overcharging and overdischarging of the battery by the BMS, which will affect the safe operation of the battery energy storage system, greatly shorten the service life of the battery cell, and cause heat explosion in severe cases.
  • the charging system will automatically disconnect to complete the charging, but the battery pack module and BMS module inside the battery have static loss, and will automatically lose power after a long time.
  • the remaining power is constantly decreasing, and even over-discharge occurs, causing irreversible and serious loss to the battery.
  • the ampere-hour measurement method does not take into account the impact of battery self-consumption when estimating the remaining power.
  • the battery will always display the remaining power in the last use state, that is, when it is fully charged and there is no external load, the remaining power will always be displayed as 100%. .
  • the battery Even if the battery is connected to an external power source, the battery will not be charged, and the mobile energy storage battery will be in a state of insufficient power or no power for a long time.
  • the object of the present invention is to provide a control method for self-maintenance of batteries that are often charged, which combines the ampere-hour measurement method with the self-consumption rate, can accurately estimate the actual remaining power of the battery, and realize regular charging maintenance,
  • the function of automatic maintenance, thereby improving the application reliability and service life of the energy storage battery has the advantages of simple principle, easy implementation and high accuracy.
  • a control method for self-maintenance of batteries often charged comprising the steps of:
  • S20 In the state where the battery is not discharged externally, calculate the actual remaining power of the battery in real time according to the current self-consumption rate, and charge the battery to the target power when the battery is connected to an external power supply; or S30: When the battery has been discharged In the state of external discharge, the actual remaining power of the battery is calculated in real time through the ampere-hour measurement method and the current self-consumption rate, and the battery is charged to the target power when the battery is connected to an external power supply.
  • the control method for self-maintenance of a battery that is often charged according to the present invention is based on the ampere-hour measurement method, accurately estimates the actual remaining power of the battery in real time through the self-consumption rate, and realizes the function of regular automatic power replenishment, avoiding Errors in the estimation of the remaining power lead to overcharging and overdischarging of the battery and the limitations of emergency functions, thereby improving the application reliability and life of the energy storage battery. It has the advantages of simple algorithm, economical and practical, and strong reliability.
  • the battery After the battery is fully discharged, the battery is fully charged, and the OCV-SOC curve when it is charged is recorded; the target power is set, and the target voltage corresponding to the target power is read from the OCV-SOC curve; the battery is not discharged for a period of time time.
  • step S20 is specifically:
  • a represents the current self-consumption rate
  • Q represents the charging capacity
  • T 0 represents the preset power replenishment period
  • SOC represents the actual remaining power of the battery at time t
  • X 0 represents the target power
  • the value range of t is 0 ⁇ t ⁇ T 0 .
  • step S30 is specifically:
  • the power to be supplemented is calculated; when the charging capacity of the battery is equal to the power to be replenished, the battery has been charged to the target power.
  • the present invention also provides a battery that is always charged and self-maintained, including a battery unit and a BMS unit, the battery unit includes at least one battery pack that can perform multiple charge and discharge cycles, and the BMS unit includes Control module, recording module, detection module, current self-consumption rate calculation module, first calculation module of actual remaining power, time calculation module, first judgment module of actual remaining power and second calculation module of actual remaining power;
  • the control module After the battery is fully discharged, the control module fully charges the battery at a preset charging rate; the recording module records the charging time of the battery after the battery is fully discharged and fully charged. OCV-SOC curve; the recording module also sets a preset power replenishment period and target power, and reads the target voltage in the OCV-SOC curve; the control module is placed in a state where the battery is not discharged externally After a period of time, charge the battery to the target electric quantity; the recording module also records the charging quantity of the battery during the charging process; the current self-consumption rate calculation module calculates the battery's charge according to the charging quantity The current self-consumption rate; the detection module judges whether the battery has been discharged;
  • the first calculation module of the actual remaining power calculates the actual remaining power of the battery in real time according to the current self-consumption rate when the battery is not discharged; the time calculation module records the remaining power when the battery is not discharged.
  • the duration of power replenishment and judge whether the duration of power replenishment is greater than or equal to the preset power replenishment period; the detection module also judges whether the battery is connected to an external power supply; the control module is still in the duration of power replenishment When it is greater than or equal to the preset power replenishment period and the battery is connected to an external power supply, the battery is automatically charged; the first judging module of the actual remaining power judges whether the battery is charged to the target power; the control module After the battery is charged to the target power level, the automatic charging of the battery ends; the detection module also determines whether the battery has been discharged before automatic charging;
  • the second calculation module of the actual remaining power calculates the actual remaining voltage of the battery in real time according to the ampere-hour measurement method and the current self-consumption rate when the battery has been discharged.
  • the battery also includes an early warning unit
  • the BMS unit also includes a second judging module for actual remaining power and a completely discharged judging module;
  • the second judging module of the actual remaining power judges whether the actual remaining power of the battery falls below the warning power when the battery is not connected to an external power supply;
  • the full discharge judging module judges whether the battery has been fully discharged
  • the warning unit sends a warning signal when the actual remaining power of the battery drops below the warning power.
  • the present invention provides a control method for constantly charged self-maintenance of the battery and a normally charged self-maintained battery, which introduces the self-consumption rate to accurately estimate the actual remaining power of the battery, and realizes regular charging maintenance,
  • the function of automatic maintenance and low power warning can avoid the phenomenon of power shortage or overcharge and overdischarge during emergency use, thereby improving the application reliability and service life of the energy storage battery. It has the advantages of simple principle, easy implementation and strong stability .
  • FIG. 1 is a flow chart of the steps of a control method for self-maintenance of a battery that is always charged and provided by an embodiment of the present invention
  • FIG. 2 is a schematic diagram of the OCV-SOC curve of a LiFePO battery provided by an embodiment of the present invention when it is charged at different charging rates;
  • Fig. 3 is a schematic diagram of the OCV-SOC curve when the LiMn 2 O 4 battery and the LiFePO 4 battery provided by an embodiment of the invention are charged at the same charging rate;
  • Fig. 4 is a schematic diagram of the OCV-SOC curve when charging and discharging the ternary lithium battery provided by an embodiment of the invention
  • Fig. 5 is a flow chart of the steps of a control method for self-maintenance of a battery when it is always charged according to an embodiment of the present invention
  • FIG. 6 is a flow chart of steps of a control method for self-maintenance of a battery that is constantly charged according to an embodiment of the present invention.
  • Li-ion batteries include lithium-ion batteries (referred to as lithium batteries, Lithium Ion Batteries, LIB), lead-acid batteries and vanadium flow batteries.
  • lithium-ion batteries include lithium cobalt oxide (LiCoO 2 ) batteries, lithium manganese oxide (LiMn 2 O 4 ) batteries, nickel-cobalt-manganese lithium batteries (ie ternary lithium batteries, Li(NiCoMn)O 2 , NMC) and iron phosphate Lithium (LiFePO 4 ) battery.
  • the present invention introduces the self-consumption rate to correct the remaining power, realizes the real-time and accurate estimation of the actual remaining power of the battery, and realizes the functions of automatic charging and regular maintenance.
  • the control method of the constant charging self-maintenance includes steps:
  • the battery is charged to the target power level, and its current self-consumption rate is calculated according to the charging capacity.
  • the actual remaining power of the battery is calculated in real time according to the current self-consumption rate, and the battery is charged to the target power when the battery is connected to an external power supply;
  • the actual remaining power of the battery is calculated in real time through the ampere-hour measurement method and the current self-consumption rate, and the battery is charged to the target power when the battery is connected to an external power supply.
  • FIG. 1 is a flow chart of the steps of a control method for self-maintenance of a battery that is always charged and provided in this embodiment.
  • the control method comprises the steps of:
  • step S1 the battery is fully discharged when the battery is used for the first time, or when the battery is not used for a long time, from power consumption to full discharge;
  • the charging rate refers to the time when the battery is fully charged to its rated capacity within a specified time.
  • the preset charging rate is set first, and after the battery is fully discharged, it is fully charged at the preset charging rate, and the OCV-SOC curve is recorded.
  • the preset charging rate includes a fast charging rate and a slow charging rate, wherein, when the preset charging rate is less than or equal to 0.3C, it is a slow charging rate, and when the preset charging rate is greater than 0.3C, it is a fast charging rate.
  • the battery will generate heat during the charging process, causing the temperature to rise, thereby affecting the voltage and capacity of the battery; and when the charging rate is within a certain range, the heat generated during the charging process is very small, and the influence of temperature on the voltage and power can be ignored; On the one hand, increasing the charging rate will accelerate the growth of battery internal resistance and capacity decay. Therefore, in this embodiment, it is preferable to use the slow charging rate to charge the mobile energy storage battery, so as to generate the OCV-SOC curve during battery charging. In the actual application process, the user can also reset the charging rate.
  • the remaining power in the OCV-SOC curve is calculated based on the ampere-hour measurement method, which is defined as the ratio of the remaining capacity of the battery to the rated capacity of the battery, and its calculation formula is as follows:
  • C 0 represents the rated capacity of the battery
  • C t represents the remaining capacity of the battery at time t
  • the remaining capacity is redefined as the ratio of the remaining capacity to the actual maximum capacity, and the expression is as follows:
  • C max represents the actual maximum capacity updated after each full charge of the battery.
  • the OCV-SOC curve of the battery needs to be re-recorded at a preset charge rate, so as to improve the accuracy of remaining power estimation.
  • step S2 the value range of the target electric quantity X 0 is 30% ⁇ X 0 ⁇ 95%, and its value can also be set according to the actual needs of the user.
  • the target electric quantity X 0 90%.
  • step S3 after placing the battery for T 0 days without external discharge, charge the battery to the target power level; where T 0 is the preset charging period, which means that the battery needs regular maintenance when it is not charged and discharged ,
  • T 0 is the preset charging period, which means that the battery needs regular maintenance when it is not charged and discharged
  • the time interval of automatic power replenishment, its value can also be set according to the actual needs of users.
  • the battery When the battery is not discharged externally, since there is no charging and discharging current, the remaining power is estimated by the traditional ampere-hour measurement method. After T 0 days, the remaining power will still show 100%, and the battery will not be automatically charged. However, the self-consumption of the battery will cause its actual remaining power to be less than 100%, and it will continue to decrease with time, and the voltage at both ends of the battery will also decrease. Therefore, in this embodiment, after placing the battery for T0 days without external discharge, the battery is charged, and the charging voltage of the battery is recorded. When the charging voltage is equal to the target voltage, it means that the battery is charged to the target power.
  • step S4 the charging amount of the battery during the charging process is calculated in real time through the ampere-hour measurement method.
  • the charging amount of the battery during the entire charging process is recorded, and the charging amount is the battery when there is no external discharge.
  • the self-consumption power is used to calculate the subsequent self-consumption rate.
  • step S5 the formula for calculating the self-consumption rate is:
  • a represents the current self-consumption rate of the battery
  • Q represents the charging capacity of the battery during charging, which is numerically equal to the self-consumption power of the battery during storage.
  • step S6 it is necessary to first judge whether the battery has been discharged externally, and then calculate the actual remaining power of the battery in different ways according to the judgment result.
  • control method further includes the steps of:
  • S11 In the state of no external discharge of the battery, calculate the actual remaining power of the battery in real time according to the current self-consumption rate, and record the time to be replenished;
  • S12 Determine whether the waiting time for power replenishment is greater than or equal to the preset power replenishment period
  • S14 Automatically charge the battery
  • S15 Real-time judge whether the battery reaches the target power level
  • S17 Determine whether the battery has been discharged externally before automatic charging.
  • step S11 since the battery is not discharged externally, its actual remaining power is only affected by internal self-consumption, then the actual remaining power of the battery can be calculated in real time according to the self-consumption rate calculated in step S5, and its calculation formula is :
  • SOC represents the actual remaining power of the battery at time t
  • the value range of t is 0 ⁇ t ⁇ T 0 .
  • the waiting time for recharging refers to the elapsed time after the battery is charged, or the elapsed time after the battery is charged to the target power level; automatic recharging or self-maintenance means that the battery automatically recharges after a period of time without external discharge. The act of charging.
  • step S12 it is judged whether the waiting time for power replenishment is greater than or equal to the preset power replenishment period, then:
  • step S11 that is, continue to calculate the actual remaining power in real time according to the current self-consumption rate
  • step S13 is executed.
  • step S13 when T ⁇ T 0 , it is judged whether the battery is connected to an external power source, that is, whether the battery can be automatically recharged; when the battery is connected to an external power source, step S14 is executed.
  • step S14 when T ⁇ T 0 and the battery is connected to an external power supply, the battery is automatically recharged, so as to ensure the reliability of the battery and avoid performance damage and lifespan reduction of the battery due to over-discharge.
  • step S15 it is necessary to judge whether the battery has been automatically charged to the target power level. There are two methods for judging:
  • step S16 that is, end the automatic power replenishment
  • step S14 is executed.
  • step S17 after the automatic charging is finished, it is necessary to determine whether the battery has been discharged externally before the automatic charging, or in other words, determine whether the automatic charging process of the battery is an automatic charging process.
  • step S4 is re-executed. That is to say, every time the battery is automatically recharged, the charge amount in the charging process must be recorded, and the current self-consumption rate of the battery is calculated according to the charge amount, and the current self-consumption rate is only used to calculate the time until the end of the automatic recharge. The actual remaining power before the next automatic power replenishment to improve the accuracy of remaining power estimation.
  • the battery when the battery records the OCV-SOC curve and automatically recharges the battery in the charging state, the battery cannot have an external load, that is, the battery cannot be charged and discharged at the same time, otherwise the estimation of the remaining power will be relatively large. error.
  • FIG. 2 is the OCV-SOC curve recorded by charging the LiFePO 4 battery provided in this embodiment at different charging rates.
  • the OCV-SOC curve of the LiFePO 4 battery includes the first identification area (>85%), the voltage flat area (30%-85%) and the second identification area ( ⁇ 85%).
  • the charging voltage in the first identification area and the second identification area changes greatly, but the charging voltage in the voltage flat area does not change significantly. If the target power level is in the voltage flat area, it is difficult to judge whether the battery is charged to the target power level by the voltage method, and there are large errors in the estimation results.
  • the battery in order to prevent the battery from having a bad impact on the capacity and life of the battery when the battery is in extreme working conditions, the battery should be controlled not to work at both ends of the OCV-SOC curve, nor should the battery be at both ends of the OCV-SOC curve. Correct the remaining power.
  • the target power is set in the voltage flat region, and the power method can only be used to determine whether the battery is charged to the target power.
  • step S15 when T ⁇ T 0 and the battery is connected to an external power source, the battery is automatically recharged, and the battery is judged to be charged to the target power in real time by the power method.
  • step S4 is re-executed.
  • the current self-consumption rate calculated by the formula (3) has not changed. That is to say, when the electric quantity method is used for judgment, the current self-consumption rate is only calibrated when the battery is automatically replenished for the first time, so after the automatic replenishment is completed, step S5 can be directly executed.
  • the aforementioned voltage method or power method can be used to determine whether the battery is charged to the target power.
  • the voltage method can re-calibrate the current self-consumption rate every time the power is automatically replenished, while the electric quantity method only calibrates the current self-consumption rate when the power is automatically replenished for the first time. Therefore, for the LiFePO 4 battery, and When the target electric quantity is set in the voltage flat area, it is preferable to use the voltage method to judge, so as to improve the accuracy of the remaining electric quantity estimation.
  • Figure 3 is a comparison chart of the OCV-SOC curves of the LiMn 2 O 4 battery and the LiFePO 4 battery provided in this example when charged at the same charging rate
  • Figure 4 is the ternary lithium battery provided in this example.
  • OCV-SOC curve when the battery is charging and discharging It can be seen from the figure that during the charging process, LiMn 2 O 4 batteries and ternary lithium batteries do not have a voltage flat region unlike LiFePO 4 batteries, and their charging voltage varies greatly within the entire range of remaining power values. Therefore, for mobile energy storage batteries other than LiFePO 4 batteries, when the value range of the target power is 30% to 95%, the voltage method is used to judge whether the battery is charged to the target power. In other embodiments, the power method can also be used. judge.
  • this embodiment provides a control method for battery self-maintenance when it is always charged.
  • the self-consumption rate of the battery By calculating the self-consumption rate of the battery, it can accurately estimate the actual remaining power of the battery when there is no external discharge in real time, and realize regular automatic maintenance.
  • the function of supplementary power maintenance prevents the battery from being in a low-power or no-power state due to long-term idleness, avoids the phenomenon of overcharge and overdischarge of the battery, ensures the reliability of the battery, and prolongs the service life of the battery.
  • this embodiment also includes method steps in the state that the battery has been discharged to the outside and the state that the battery is not connected to an external power supply.
  • FIG. 5 is a flow chart of the steps of a control method for self-maintenance of a battery that is always charged and provided in this embodiment.
  • the control method also includes the steps of:
  • S23/S13 Determine whether the battery is connected to an external power supply
  • step S6 it is judged whether the battery has been discharged to the outside, if the battery has not been discharged to the outside, execute steps S11-S17 described in Embodiment 1; if the battery has been discharged to the outside, execute step S21.
  • step S21 the ampere-hour measurement method is to continuously detect and integrate the charging/discharging current to obtain the electric quantity released or absorbed by the battery, so as to obtain the remaining electric quantity of the battery.
  • the calculation formula is:
  • step S22 when the battery is not discharged externally, since there is no discharge current, the actual remaining power of the battery in the case of self-consumption cannot be obtained through the ampere-hour measurement method. Therefore, this embodiment introduces real-time correction of the current self-consumption rate The remaining power, so as to obtain the actual remaining power of the battery, the calculation formula is as follows:
  • step S23 (actually also step S13), because the battery has been discharged externally, the battery power is low, and it needs to be charged urgently. At this time, it is not necessary to judge whether the waiting time for charging is greater than or equal to the preset charging period, and directly judge whether the battery is connected to an external power supply;
  • step S14 When the battery is connected to an external power source, steps S14 to S17 described in Embodiment 1 are executed, but in this process, there are two differences between this embodiment and Embodiment 1: first, the automatic charging of the battery described in step S14 , because the battery has been discharged externally, so it can only be called automatic charging, not automatic power replenishment; secondly, the judgment result of step S17 is that the battery has been discharged externally before automatic charging, or the battery is not automatically replenished, then The self-consumption rate cannot be calculated by the charging amount in the automatic charging process, so step S4 cannot be performed in the next step, but step S6 should be performed.
  • a low-power warning function is set, that is, steps S24-25 are executed.
  • step S24 when the battery is not connected to an external power supply, continue to calculate the actual remaining power of the battery in real time according to formula (4) or formula (6);
  • the current self-consumption rate used to calculate the actual remaining power can be the current self-consumption rate calibrated during the last automatic power replenishment, or the current self-consumption rate after multiple automatic replenishment The maximum self-consumption rate obtained after power-on.
  • step S25 When SOC> Xa , the low power warning function will not be triggered, and then continue to execute step S25;
  • step S26 is performed, that is, an early warning signal is sent.
  • an early warning signal is sent every time the actual remaining power of the battery decreases by 5%.
  • this embodiment provides a control method for the self-maintenance of the battery when it is always charged.
  • the ampere-hour measurement method combined with the self-consumption rate of the battery, it can be real-time regardless of whether the battery has been discharged to the outside. Accurately estimate the actual remaining power of the battery, and realize the functions of automatic charging and low battery warning, ensuring the reliability of the battery.
  • this embodiment further includes method steps in a fully discharged state of the battery.
  • FIG. 6 is a flow chart of the steps of a control method for self-maintenance of a battery that is always charged and provided in this embodiment. It can be seen from the figure that after step S17 is executed, step S4 or step S6 can be re-executed, that is, the OCV-SOC curve recorded after the battery is completely discharged once can be used for multiple automatic power replenishment/charging cycles. In step S26, even if the warning signal has been sent, the battery may not be able to be charged, and it will continue to be completely discharged from power consumption, then the control method also includes the steps
  • step S13 is performed to judge whether the battery is connected to an external power supply again;
  • step S1 is performed to record the OCV-SOC curve of the battery at the preset charging rate again, and use the updated OCV-SOC curve to start a new automatic power supply/charging cycle.
  • the performance of the battery changes with the increase of the number of charge and discharge cycles, so the estimation of the actual remaining power of the battery is preferably based on the latest recorded parameters and curves to improve the accuracy of battery state estimation, thereby improving the stability of battery use performance and reliability, and effectively extend its working life.
  • this embodiment Based on the control method for the self-maintenance of the battery when it is constantly charged as described in Embodiment 3, this embodiment also provides a self-maintenance battery that is always charged.
  • the battery includes a battery unit, a BMS unit and an early warning unit.
  • the battery unit includes at least one battery pack capable of multiple charge and discharge cycles.
  • the BMS unit includes a control module, a recording module, a detection module, a current self-consumption rate calculation module, a first calculation module for the actual remaining power, a time calculation module, a first judgment module for the actual remaining power, a second calculation module for the actual remaining power, and a second calculation module for the actual remaining power.
  • the second electric quantity judging module and the complete discharge judging module are included in the control module, a recording module, a detection module, a current self-consumption rate calculation module, a first calculation module for the actual remaining power, a time calculation module, a first judgment module for the actual remaining power, a second calculation module for the actual remaining power, and a second calculation module for the actual remaining power.
  • the control module After the battery is fully discharged, the control module makes the battery fully charged at the preset charging rate; the recording module records the OCV-SOC curve of the battery when the battery is fully discharged and fully charged; the recording module also sets the preset The charging period and target power, and read the target voltage in the OCV-SOC curve; the control module charges the battery to the target power after the battery is not discharged for a period of time; the recording module also records the battery charging process. Charging capacity; the current self-consumption rate calculation module calculates the current self-consumption rate of the battery according to the charge capacity; the detection module judges whether the battery has been discharged.
  • the first calculation module of the actual remaining power calculates the actual remaining power of the battery in real time according to the current self-consumption rate when the battery is not discharged externally; the time calculation module records the time to be replenished when the battery is not discharged externally, and judges the time to be replenished Whether it is greater than or equal to the preset power replenishment period; the detection module also judges whether the battery is connected to an external power supply; when the control module is still waiting for power replenishment and is longer than or equal to the preset power replenishment period and the battery is connected to an external power supply, the battery is automatically charged; the actual remaining power The first judging module judges whether the battery is charged to the target power; the control module stops the automatic charging of the battery after the battery is charged to the target power; the detection module also judges whether the battery has been discharged before automatic charging.
  • the second calculation module of the actual remaining power calculates the actual remaining voltage of the battery in real time according to the ampere-hour measurement method and the current self-consumption rate when the battery has been discharged; the second judgment module of the actual remaining power judges the battery when the battery is not connected to an external power supply. Whether the actual remaining power of the battery falls below the warning power; the complete discharge judging module judges whether the battery has been fully discharged.
  • the warning unit sends an early warning signal when the actual remaining power of the battery drops below the warning power.
  • this embodiment provides a self-maintaining battery that is always charged, on the basis of the ampere-hour measurement method, the self-consumption rate is introduced to calculate and correct the SOC, and the SOC can be accurately estimated in real time , and realize the functions of automatic charging, regular maintenance and low-battery warning, avoiding the phenomenon of power shortage or overcharging and overdischarging during emergency use, and has the advantages of simple overall structure, easy implementation, strong reliability and long working life.

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Abstract

本发明涉及一种电池常带电自保养的控制方法及常带电自保养的电池。本发明所述的电池常带电自保养的控制方法包括如下步骤：S10：在电池电量至少达到目标电量且无对外放电的一段时间后，对电池进行充电至目标电量，根据充电量计算其当前自耗电率；S20：在电池无对外放电的状态下，根据所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量；或S30：在电池已对外放电的状态下，通过安时计量法和所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量。该控制方法能精确估算电池的实际剩余电量，并实现定期充电维护、自动保养的功能。

Description

一种电池常带电自保养的控制方法及常带电自保养的电池 技术领域
本发明涉及移动储能电池的技术领域，特别是涉及一种电池常带电自保养的控制方法及常带电自保养的电池。
背景技术
随着电动汽车的发展，电池管理系统(Battery Management Systems,BMS)得到了广泛的应用。电池荷电状态(stage of charge,SOC)为电池当前剩余容量与电池实际可用容量的比值，其作为BMS的主要参数，可充分发挥电池系统的动力性能，提高电池使用的安全性，防止电池过充过放，从而延长电池的使用寿命，保证电池的续航市场，其精确估算是BMS主要功能得以实现的前提。
现有技术中，剩余电量估量方法有以下几种：依靠于电流积分的安时计量法，通过测量端电压的开路电压法和电动势法，基于多量样本原始数据与神经网络模型的神经网络法，以及基于电池状态空间模型和递推公式的卡尔曼滤波方法等。相较于其他剩余电量估量方法，安时计量法原理简单，工作稳定，易于实现，设备成本低，具有较高的可靠性和经济性，在实际工程中得到了广泛应用。但传统的安时积分法准确性依赖于初始剩余电量的估计精度，且随着电池使用时间的增长，在电流时间积分过程中，也会存在累计的积分误差，整体剩余电量估算精度会随时间而逐渐下降，出现剩余电量估算误差逐渐积累、精度不断下降等问题。而错误的剩余电量估算结果会导致BMS对电池过充过放，影响电池储能系统的安全运行，大大缩短电池电芯的使用寿命，严重时会引起发热爆炸。
另一方面，移动储能电池在充满电后，充电系统会自动断开，完成充电，但是电池内部的电池组模块和BMS模块都存在静态损耗，放置时间长了会自动掉电，电池的实际剩余电量在不断下降，甚至产生过放现象，对电池造成不可逆转的严重损耗。而安时计量法在进行剩余电量估算时没有考虑到电池自耗电的影响，电池会一直显示最后使用状态下的剩余电量，即充满电且没有外接负载时，剩余电量会一直显示为100％。此时，即使电池已连接外接电源也不会对电池进行充电，移动储能电池将长期处于不满电或没有电的状态，在应急或者户外应用时不能提供足够的电能甚至无法使用，无法实现其应有的储能功能以及紧急状态下的应急功能。所以，目前的移动储能电池都需要定期进行充电维护，即在长期放置一段时间后再进行充电。
发明内容
基于此，本发明的目的在于，提供一种电池常带电自保养的控制方法，将安时计量法和自耗电率相结合，能够精确地估算电池的实际剩余电量，并实现定期充电维护、自动保养的功能，从而提高储能电池的应用可靠性和使用寿命，具有原理简单、易于实现、准确性高的优点。
本发明是通过如下技术方案实现的：
一种电池常带电自保养的控制方法，包括步骤：
S10：在电池电量至少达到目标电量且无对外放电的一段时间后，对电池进行充电至目标电量，根据充电量计算其当前自耗电率；
S20：在电池无对外放电的状态下，根据所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量；或S30：在电池已对外放电的状态下，通过安时计量法和所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量。
本发明所述的一种电池常带电自保养的控制方法，在安时计量法的基础上，通过自耗电率实时精确估算电池的实际剩余电量，并实现定期自动补电的功能，避免了剩余电量估算错误导致电池过充过放、无法发挥应急功能的局限性，从而提高储能电池的应用可靠性和寿命，具有算法简单、经济实用、可靠性强的优点。
进一步地，还包括步骤：
在电池完全放电后使电池充满电，记录其充电时的OCV-SOC曲线；设定目标电量，并在所述OCV-SOC曲线读取所述目标电量对应的目标电压；使电池不对外放电一段时间。
进一步地，步骤S20具体为：
在电池无对外放电的状态下，根据所述当前自耗电率实时计算电池的实际剩余电量；记录待补电时长；当待补电时长大于等于预设补电期限且电池连接外接电源时，对电池进行充电至目标电量。
进一步地，所述当前自耗电率的计算公式为：
Figure PCTCN2022082537-appb-000001
式中，a表示当前自耗电率，Q表示充电量，T 0表示预设补电期限。
进一步地，所述实际剩余电量的计算公式为：SOC＝X 0-a×t    (4)
式中，SOC表示电池在t时刻的实际剩余电量，X 0表示目标电量，t的取值范围为0≤t≤T 0。
进一步地，步骤S30具体为：
在电池已对外放电的状态下，根据所述安时计量法计算电池对外放电后的剩余电量；根据所述当前自耗电率实时修正所述剩余电量，获得实际剩余电量；在电池连接外接电源时，对电池进行充电至所述目标电量。
进一步地，当电池的充电电压等于所述目标电压时，电池已充电至所述目标电量；
或者，
根据电池的实际剩余电量，计算电池的待补充电量；当电池的充电量等于所述待补充电量时，电池已充电至所述目标电量。
进一步地，还包括步骤：
当电池的实际剩余电量降至预警电量以下且未与外接电源连接时，发送预警信号。
基于上述控制方法，本发明还提供了一种常带电自保养的电池，包括电池单元和BMS单元，所述电池单元包括至少1个可进行多次充放电循环的电池组，所述BMS单元包括控制模块、记录模块、检测模块、当前自耗电率计算模块、实际剩余电量第一计算模块、时间计算模块、实际剩余电量第一判断模块和实际剩余电量第二计算模块；
所述控制模块在所述电池完全放电后，使所述电池在预设充电倍率下充满电；所述记录模块在所述电池完全放电后并充满电的过程中，记录所述电池充电时的OCV-SOC曲线；所述记录模块还设定预设补电期限和目标电量，并在所述OCV-SOC曲线中读取目标电压；所述控制模块在所述电池不对外放电的状态下放置一段时间后，使所述电池充电至所述目标电量；所述记录模块还记录所述电池充电过程中的充电量；所述当前自耗电率计算模块根据所述充电量计算所述电池的当前自耗电率；所述检测模块判断电池是否已对外放电；
所述实际剩余电量第一计算模块在所述电池无对外放电时，根据所述当前自耗电率实时计算所述电池的实际剩余电量；所述时间计算模块在电池无对外放电时，记录待补电时长，并判断所述待补电时长是否大于等于所述预设补电期限；所述检测模块还判断所述电池是否与外接电源连接；所述控制模块还在所述待补电时长大于等于所述预设补电期限且所述电池连接外接电源时，使所述电池自动充电；所述实际剩余电量第一判断模块判断所述电池是否充电到所述目标电量；所述控制模块还在所述电池充电到所述目标电量后，使所述电池结束自动充电；所述检测模块还判断电池自动充电前是否已对外放电；
所述实际剩余电量第二计算模块在所述电池已对外放电时，根据安时计量法和所述当前自耗电率实时计算所述电池的实际剩余电压。
进一步地，所述电池还包括预警单元；
所述BMS单元还包括实际剩余电量第二判断模块和完全放电判断模块；
所述实际剩余电量第二判断模块在所述电池不连接外接电源时，判断所述电池的实际剩 余电量是否降至预警电量以下；
所述完全放电判断模块判断电池是否已完全放电；
所述预警单元在所述电池的实际剩余电量降至预警电量以下时发送预警信号。
与现有技术相比，本发明提供的一种电池常带电自保养的控制方法及常带电自保养的电池，引入自耗电率对电池的实际剩余电量进行精确估算，并实现定期充电维护、自动保养、低电预警的功能，避免出现应急使用时缺电少电或过充过放现象，从而提高储能电池的应用可靠性和使用寿命，具有原理简单、易于实现、稳定性强的优点。
为了更好地理解和实施，下面结合附图详细说明本发明。
附图说明
图1为本发明一实施例提供的一种电池常带电自保养的控制方法的步骤流程图；
图2为本发明一实施例提供的LiFePO 4电池在不同充电倍率下充电时的OCV-SOC曲线示意图；
图3为发明一实施例提供的LiMn 2O 4电池和LiFePO 4电池在同一充电倍率下充电时的OCV-SOC曲线示意图；
图4为发明一实施例提供的三元锂电池充放电时的OCV-SOC曲线示意图；
图5为本发明一实施例提供的一种电池常带电自保养的控制方法的步骤流程图；
图6为本发明一实施例提供的一种电池常带电自保养的控制方法的步骤流程图。
具体实施方式
移动储能电池(简称电池)包括锂离子电池(简称锂电池，Lithium Ion Batteries,LIB)、铅酸蓄电池和钒液流电池。其中，锂离子电池包括钴酸锂(LiCoO 2)电池、锰酸锂(LiMn 2O 4)电池、镍钴锰锂电池(即三元锂电池，Li(NiCoMn)O 2，NMC)和磷酸铁锂(LiFePO 4)电池。由于现有技术中剩余电量估算方法均没有考虑到电池本身的自耗电，所以对电池的剩余电量估算不准，容易引发电池过充过放，从而影响电池的性能和寿命。本发明引入自耗电率对剩余电量进行修正，实现对电池实际剩余电量的实时精确估算，并实现自动充电、定期维护的功能，其常带电自保养的控制方法包括步骤：
在电池完全放电后使电池充满电，记录其充电时的OCV-SOC曲线；设定目标电量，并在OCV-SOC曲线中读取目标电量对应的目标电压；使电池不对外放电一段时间，然后对电池进行充电至目标电量，根据充电量计算其当前自耗电率；
或者，在电池电量达到目标电量且无对外放电的一段时间后，对电池进行充电至目标电量，根据充电量计算其当前自耗电率。
在电池无对外放电的状态下，根据当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量；
在电池已对外放电的状态下，通过安时计量法和所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量。
为使本发明的目的、技术方案和优点更加清楚，下面通过具体的实施例作进行说明。
实施例1
请参阅图1，其为本实施例提供的一种电池常带电自保养的控制方法的步骤流程图。该控制方法包括步骤：
S1：在电池完全放电后，使电池在预设充电倍率下充满电，记录电池充电时的充电电压(或开路电压，Open Circuit Voltage,OCV)-剩余电量(或荷电状态，Stage of Charge,SOC)曲线；
S2：设定目标电量，并在OCV-SOC曲线读取目标电量对应的目标电压；
S3：在电池不对外放电的状态下放置一段时间后，对电池充电至目标电量；
S4：记录充电过程的充电量；
S5：根据充电量计算电池的当前自耗电率；
S6：判断电池是否已对外放电。
在步骤S1中，电池完全放电可以是在电池首次使用时使其完全放电，或者在电池长时间不使用，自耗电至完全放电；充电倍率是指电池在规定时间内充满其额定容量时所需要的电流值，例如额定容量C 0＝1A·h的电池以1C的充电倍率充电，1小时后达到满电状态，其充电电流恒定为I＝1A，即电池采用恒流充电模式进行充电。在本实施例中，先设定好预设充电倍率，在电池完全放电后，使其在预设充电倍率下充满电，并记录OCV-SOC曲线。
预设充电倍率包括快充充电倍率和慢充充电倍率，其中，预设充电倍率小于等于0.3C时为慢充充电倍率，预设充电倍率大于0.3C时为快充充电倍率。电池在充电过程中会产生热量，导致温度升高，从而影响电池的电压和容量；而当充电倍率在一定范围内，充电过程产生的热量很小，可以忽略温度对电压和电量的影响；另一方面，提高充电倍率会加速电池内阻增长和容量衰减。因此，在本实施例中，优选采用慢充充电倍率为移动储能电池充电，从而生成电池充电时的OCV-SOC曲线，在实际应用过程中，用户也可对充电倍率进行重新设定。
其中，OCV-SOC曲线中的剩余电量是基于安时计量法进行计算的，其定义为电池剩余容量与电池额定容量的比值，其计算公式如下：
Figure PCTCN2022082537-appb-000002
式中，C 0表示电池的额定容量，C t表示电池在t时刻的剩余容量；剩余电量的取值范围为0～100％，当SOC＝0％时表示电池完全放电，当SOC＝100％时表示电池满电。
在实际应用中，电池电量不可能一直保持额定容量，故将剩余电量重新定义为剩余容量与实际最大容量的比值，其表达式如下：
Figure PCTCN2022082537-appb-000003
式中，C max表示电池每次充满电后更新的实际最大容量。
优选的，每次电池完全放电(即SOC＝0％)时，需要在预设充电倍率下重新记录电池的OCV-SOC曲线，以提高剩余电量估算的精度。
在步骤S2中，目标电量X 0的取值范围为30％＜X 0≤95％，其数值同样可根据用户的实际需求进行设定，优选的，目标电量X 0＝90％。
在步骤S3中，在电池不对外放电的状态下放置T 0天后，对电池充电至目标电量；其中，T 0为预设补电期限，是指电池在没有充放电的情况下需要进行定期维护、自动补电的时间间隔，其数值也可根据用户的实际需要进行设定。
在电池不对外放电的状态下，由于没有充放电电流，采用传统的安时计量法估算剩余电量，放置T 0天后其剩余电量仍会显示100％，也不会对电池进行自动充电。但电池的自耗电会导致其实际剩余电量小于100％，并且随着时间的增长而不断降低，电池两端的电压也随之降低。因此，在本实施例中，在电池不对外放电的状态下放置T 0天后，对电池进行充电，记录电池的充电电压，当充电电压等于目标电压时，意味着电池充电至目标电量。
在步骤S4中，通过安时计量法，实时计算电池在充电过程中的充电量，当电池充电至目标电量，记录电池在整个充电过程的充电量，该充电量即为电池在无对外放电时的自耗电量，用于后续自耗电率的计算。
在步骤S5中，自耗电率的计算公式为：
Figure PCTCN2022082537-appb-000004
式中，a表示电池的当前自耗电率，Q表示电池充电过程中的充电量，在数值上等于电池在放置期间的自耗电量。
在步骤S6中，需要先判断电池是否已对外放电，然后根据判断结果采用不同方式计算电 池的实际剩余电量。
当步骤S6的判断结果为电池无对外放电时，该控制方法还包括步骤：
S11：在电池无对外放电的状态下，根据当前自耗电率实时计算电池的实际剩余电量，并记录待补电时长；
S12：判断待补电时长是否大于等于预设补电期限；
S13：判断电池是否连接外接电源；
S14：对电池进行自动充电；S15：实时判断电池是否达到目标电量；
S16：结束自动充电；
S17：判断电池自动充电前是否已对外放电。
在步骤S11中，由于电池没有对外放电，其实际剩余电量只受内部自耗电的影响，那么就可以根据步骤S5中计算得到的自耗电率实时计算电池的实际剩余电量，其计算公式为：
SOC＝X 0-a×t    (4)
式中，SOC表示电池在t时刻时的实际剩余电量，t的取值范围为0≤t≤T 0。
在实时计算实际剩余电量的同时，还需要记录待补电时长(用符号T表示)，用于判断电池是否需要进行自动补电。其中，待补电时长是指电池在结束充电后所经过的时间，或电池充电至目标电量之后电池所经过的时间；自动补电或自保养，是指电池在无对外放电的一段时间后自动充电的行为。
在步骤S12中，判断待补电时长是否大于等于预设补电期限，则有：
当T＜T 0时，执行步骤S11，即继续根据当前自耗电率实时计算实际剩余电量；
当T≥T 0时，代表电池需要进行自动充电，则执行步骤S13。
在步骤S13中，当T≥T 0时，判断电池是否连接外接电源，即检测电池是否能自动补电；当电池连接外接电源时，执行步骤S14。
在步骤S14中，当T≥T 0且电池连接外接电源时，对电池进行自动补电，从而保证电池使用的可靠性，避免电池因过放而性能受损、寿命降低。
在步骤S15中，需要判断电池是否已经自动充电至目标电量，其判断方法有如下两种：
电压法：记录电池自动充电状态下的充电电压，并判断充电电压是否达到步骤S2读取的目标电压；当V＝V 0时，则代表SOC＝X 0。
电量法：根据步骤S11计算的实际剩余电量，计算自动补电状态下的待补充电量Q'，其 计算公式为：Q'＝X 0-SOC；记录电池自动补电状态下的充电量，并判断充电量是否达到待补充电量；当Q＝Q'时，则代表SOC＝X 0。
当实际剩余电量等于或大于等于目标电量(即SOC＝X 0)或SOC≥X 0时，执行步骤S16，即结束自动补电；
当SOC＜X 0时，代表电池仍需进行自动补电，则执行步骤S14。
在步骤S17中，结束自动充电后，需要判断电池自动充电前是否已对外放电，或者说，判断电池的自动充电过程是否为自动补电过程。
当电池自动充电前无对外放电，或电池为自动补电时，重新执行步骤S4。也就是说，每次自动补电时，都要记录充电过程的充电量，并根据充电量计算电池的当前自耗电率，而当前自耗电率仅用于计算这次自动补电结束到下次自动补电之前的实际剩余电量，以提高剩余电量估算的精确度。
需要说明的是，在本发明中，电池在充电状态下记录OCV-SOC曲线以及进行自动补电时，电池不能有外部负载，即电池不能同时进行充放电，否则剩余电量的估算将存在较大的误差。
以下提供两个示例，详细说明该控制方法的具体应用。
示例A：
请参阅图2，其为本实施例提供的LiFePO 4电池在不同充电倍率下充电所记录的OCV-SOC曲线。由图2可知，LiFePO 4电池的OCV-SOC曲线包括第一辨识区(>85％)、电压平坦区(30％～85％)和第二辨识区(≤85％)。其中，第一辨识区和第二辨识区的充电电压变化较大，而电压平坦区的充电电压变化不明显。如果目标电量位于电压平坦区，则难以通过电压法判断电池是否充电至目标电量，其估算结果也存在较大误差。同时，为了防止电池处于极限工作条件时对电池的容量和寿命产生较坏的影响，应控制电池不工作在OCV-SOC曲线的两端，也不应在电池处于OCV-SOC曲线的两端时对剩余电量进行修正。
若目标电量的取值范围为30％＜X 0≤85％(即电压平坦区)时，由于充电电压变化很小，通过前文所述的电压法判断电池是否充电至目标电量容易造成较大误差。因此，针对LiFePO 4电池，目标电量设于电压平坦区，只能采用电量法判断是否电池充电至目标电量。
那么，对于步骤S15，在T≥T 0且电池连接外接电源时，对电池进行自动补电，并通过电量法实时判断电池充电至目标电量。具体的，根据步骤S5计算的当前自耗电率，计算自动补电状态下的待补充电量Q'，其计算公式为：Q'＝X 0-SOC；记录电池自动补电状态下的充电 量，并判断充电量是否达到待补充电量；当Q＝Q'时，则代表SOC＝X 0，结束自动补电。
结束自动补电后，重新执行步骤S4，此时充电过程的充电量Q＝Q'＝a×T 0，则由公式(3)计算的当前自耗电率并没有发生改变。也就是说，采用电量法进行判断时，只在电池第一次自动补电时对当前自耗电率进行标定，因此结束自动补电后，可直接执行步骤S5。
若目标电量的取值范围为85％＜X 0≤95％(即第一辨识区)时，可采用前文所述的电压法或电量法判断电池是否充电至目标电量。其中，电压法在每次自动补电时都能重新标定当前自耗电率，而电量法只在第一次自动补电时对当前自耗电率进行标定，因此，对于LiFePO 4电池，且目标电量设于电压平坦区时，优选采用电压法进行判断，以提高剩余电量估算的精度。
示例B：
请参阅图3～4，图3为本实施例提供的LiMn 2O 4电池和LiFePO 4电池在同一充电倍率下充电时的OCV-SOC曲线对比图，图4为本实施例提供的三元锂电池充放电时的OCV-SOC曲线。由图可知，在充电过程中，LiMn 2O 4电池和三元锂电池不像LiFePO 4电池存在一个电压平坦区，其充电电压在整个剩余电量取值范围内变化较大。因此，对于除LiFePO 4电池以外的移动储能电池，目标电量的取值范围为30～95％时，均采用电压法判断电池是否充电至目标电量，在其他实施例中，也可以采用电量法进行判断。
与现有技术相比，本实施例提供的一种电池常带电自保养的控制方法，通过计算电池的自耗电率，能够实时精确估算电池无对外放电时的实际剩余电量，并实现定期自动补电维护的功能，防止电池因长时间闲置而处于低电或无电状态，避免电池出现过充过放现象，保证了电池使用的可靠性，延长电池的使用寿命。
实施例2
与实施例1相比，本实施例还包括电池已对外放电的状态下以及电池不连接外接电源的状态下的方法步骤。
请参阅图5，其为本实施例提供的一种电池常带电自保养的控制方法的步骤流程图。该控制方法还包括步骤：
S21：在电池对外放电后，根据安时计量法计算电池的剩余电量；
S22：根据当前自耗电率实时修正剩余电量，获得实际剩余电量；
S23/S13：判断电池是否连接外接电源；
S24：在电池不连接外接电源时，继续实时计算电池的实际剩余电量；
S25：判断实际剩余电量是否降至预警电量以下；
S26：发送预警信号。
在步骤S6中，判断电池是否已对外放电，若电池无对外放电，执行实施例1所述的步骤S11～S17；若电池已对外放电，则执行步骤S21。
在步骤S21中，安时计量法是通过对充/放电电流的连续检测并进行积分得到电池释放或吸收的电量，从而得出电池的剩余电量，其计算公式为：
Figure PCTCN2022082537-appb-000005
式中，SOC τ表示电池对外放电状态下在τ时刻的剩余电量；i表示电池的放电电流；τ表示电池对外放电状态的持续时间。
在步骤S22中，电池无对外放电时，由于没有放电电流，就没法通过安时计量法获取电池在自耗电情况下的实际剩余电量，因此，本实施例引入当前自耗电率实时修正剩余电量，从而获得电池的实际剩余电量，计算公式如下：
SOC＝SOC τ-a×t     (6)
在步骤S23(实际上也是步骤S13)中，由于电池已对外放电，电池电量较低，亟需充电，此时不用判断待补电时长是否大于等于预设补电期限，直接判断电池是否连接外接电源；
当电池连接外接电源时，执行实施例1所述的步骤S14～S17，但在该过程中，本实施例与实施例1存在两处不同：其一，步骤S14所述的对电池进行自动充电，因为电池已对外放电，故只能称作自动充电，而不能称其为自动补电；其二，步骤S17的判断结果为电池自动充电前已对外放电，或者为电池并非自动补电，则不能通过自动充电过程的充电量去计算自耗电率，所以下一步不能执行步骤S4，而应该执行步骤S6。
当电池不连接外接电源时，电池将持续自耗电，实际剩余电量不断降低，甚会发生过放，故设定一个低电预警功能，即执行步骤S24～25。
在步骤S24中，当电池不连接外接电源时，根据公式(4)或公式(6)继续实时计算电池的实际剩余电量；
可选的，当电池没有连接外接电源时，计算实际剩余电量所使用的当前自耗电率，可以是在上一次自动补电时标定的当前自耗电率，也可以是经过多次自动补电后得到的最大自耗电率。
在步骤S25中，判断电池的实际剩余电量是否降至预警电量以下；其中，预警电量X a的取值范围为X a≤30％，优选的，X a＝30％；在实际应用过程中，用户可根据自己的需求重 新设定预警电量。
当SOC＞X a时，不会触发低电预警功能，则继续执行步骤S25；
当SOC＝X a或SOC≤X a时，电池电量较低，则执行步骤S26，即发送预警信号。
可选的，当SOC≤X a时，电池的实际剩余电量每减少5％，就发送一次预警信号。
与现有技术相比，本实施例提供的一种电池常带电自保养的控制方法，在安时计量法的基础上，结合电池的自耗电率，不论电池是否已对外放电，都能实时精确估算电池的实际剩余电量，并实现自动充电、低电预警的功能，保证了电池使用的可靠性。
实施例3
与实施例2相比，本实施例还包括电池完全放电的状态下的方法步骤。
请参阅图6，其为本实施例提供的一种电池常带电自保养的控制方法的步骤流程图。由图可知，在执行步骤S17后可重新执行步骤S4或步骤S6，即电池在一次放电完全后所记录的OCV-SOC曲线可用于多次自动补电/充电循环。在步骤S26中，即使已发送预警信号，电池也有可能没法进行充电，不断自耗电至完全放电，则该控制方法还包括步骤
S27：发送预警信号后，判断电池是否已完全放电；
当电池未完全放电，则执行步骤S13，再次判断电池是否与外接电源连接；
当电池已完全放电，则执行步骤S1，重新在预设充电倍率下记录电池的OCV-SOC曲线，并利用更新后的OCV-SOC曲线开始新的自动补电/充电循环。
电池的性能随着充放电的循环次数增加而发生变化，因此对电池实际剩余电量的估算都优选采用最新记录的参数和曲线，以提高对电池状态预估的准确性，从而提高电池使用的稳定性和可靠性，并有效延长其工作寿命。
实施例4
基于实施例3所述的一种电池常带电自保养的控制方法，本实施例还提供了一种常带电自保养的电池。该电池包括电池单元、BMS单元和预警单元。
电池单元包括至少1个可进行多次充放电循环的电池组。
BMS单元包括控制模块、记录模块、检测模块、当前自耗电率计算模块、实际剩余电量第一计算模块、时间计算模块、实际剩余电量第一判断模块、实际剩余电量第二计算模块、实际剩余电量第二判断模块和完全放电判断模块。
控制模块在电池完全放电后，使电池在预设充电倍率下充满电；记录模块在电池完全放电后并充满电的过程中，记录电池充电时的OCV-SOC曲线；记录模块还设定预设补电期限和目标电量，并在OCV-SOC曲线中读取目标电压；控制模块在电池不对外放电的状态下放 置一段时间后，使电池充电至目标电量；记录模块还记录电池充电过程中的充电量；当前自耗电率计算模块根据充电量计算电池的当前自耗电率；检测模块判断电池是否已对外放电。
实际剩余电量第一计算模块在电池无对外放电时，根据当前自耗电率实时计算电池的实际剩余电量；时间计算模块在电池无对外放电时，记录待补电时长，并判断待补电时长是否大于等于预设补电期限；检测模块还判断电池是否与外接电源连接；控制模块还在待补电时长大于等于预设补电期限且电池连接外接电源时，使电池自动充电；实际剩余电量第一判断模块判断电池是否充电到目标电量；控制模块还在电池充电到目标电量后，使电池结束自动充电；检测模块还判断电池自动充电前是否已对外放电。
实际剩余电量第二计算模块在电池已对外放电时，根据安时计量法和当前自耗电率实时计算电池的实际剩余电压；实际剩余电量第二判断模块在电池不连接外接电源时，判断电池的实际剩余电量是否降至预警电量以下；完全放电判断模块判断电池是否已完全放电。
预警单元在电池的实际剩余电量降至预警电量以下时发送预警信号。
与现有技术相比，本实施例提供的一种常带电自保养的电池，在安时计量法的基础上，引入自耗电率对SOC进行计算和修正，能够实时地进行SOC的精确估算，并实现自动充电、定期保养和低电预警的功能，避免出现应急使用时缺电少电或过充过放现象，具有整体结构简单、容易实现、可靠性强、工作寿命长的优点。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。

Claims (10)

  1. 一种电池常带电自保养的控制方法，其特征在于，包括步骤：
    S10：在电池电量至少达到目标电量且无对外放电的一段时间后，对电池进行充电至目标电量，根据充电量计算其当前自耗电率；
    S20：在电池无对外放电的状态下，根据所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量；或S30：在电池已对外放电的状态下，通过安时计量法和所述当前自耗电率实时计算电池的实际剩余电量，并在电池连接外接电源时对电池进行充电至所述目标电量。
  2. 根据权利要求1所述的一种电池常带电自保养的控制方法，其特征在于，还包括步骤：
    在电池完全放电后使电池充满电，记录其充电时的OCV-SOC曲线；设定目标电量，并在所述OCV-SOC曲线读取所述目标电量对应的目标电压；使电池不对外放电一段时间。
  3. 根据权利要求1或2所述的一种电池常带电自保养的控制方法，其特征在于，步骤S20具体为：
    在电池无对外放电的状态下，根据所述当前自耗电率实时计算电池的实际剩余电量；记录待补电时长；当待补电时长大于等于预设补电期限且电池连接外接电源时，对电池进行充电至目标电量。
  4. 根据权利要求3所述的一种电池常带电自保养的控制方法，其特征在于：
    所述当前自耗电率的计算公式为：
    Figure PCTCN2022082537-appb-100001
    式中，a表示当前自耗电率，Q表示充电量，T 0表示预设补电期限。
  5. 根据权利要求4所述的一种电池常带电自保养的控制方法，其特征在于：
    所述实际剩余电量的计算公式为：SOC＝X 0-a×t  (4)
    式中，SOC表示电池在t时刻的实际剩余电量，X 0表示目标电量，t的取值范围为0≤t≤T 0。
  6. 根据权利要求4或5所述的一种电池常带电自保养的控制方法，其特征在于，步骤S30具体为：
    在电池已对外放电的状态下，根据所述安时计量法计算电池对外放电后的剩余电量；根据所述当前自耗电率实时修正所述剩余电量，获得实际剩余电量；在电池连接外接电源时，对电池进行充电至所述目标电量。
  7. 根据权利要求6所述的一种电池常带电自保养的控制方法，其特征在于：
    当电池的充电电压等于所述目标电压时，电池已充电至所述目标电量；
    或者，
    根据电池的实际剩余电量，计算电池的待补充电量；当电池的充电量等于所述待补充电量时，电池已充电至所述目标电量。
  8. 根据权利要求7所述的一种电池常带电自保养的控制方法，其特征在于，还包括步骤：
    当电池的实际剩余电量降至预警电量以下且未与外接电源连接时，发送预警信号。
  9. 一种常带电自保养的电池，其特征在于：
    包括电池单元和BMS单元，所述电池单元包括至少1个可进行多次充放电循环的电池组，所述BMS单元包括控制模块、记录模块、检测模块、当前自耗电率计算模块、实际剩余电量第一计算模块、时间计算模块、实际剩余电量第一判断模块和实际剩余电量第二计算模块；
    所述控制模块在所述电池完全放电后，使所述电池在预设充电倍率下充满电；所述记录模块在所述电池完全放电后并充满电的过程中，记录所述电池充电时的OCV-SOC曲线；所述记录模块还设定预设补电期限和目标电量，并在所述OCV-SOC曲线中读取目标电压；所述控制模块在所述电池不对外放电的状态下放置一段时间后，使所述电池充电至所述目标电量；所述记录模块还记录所述电池充电过程中的充电量；所述当前自耗电率计算模块根据所述充电量计算所述电池的当前自耗电率；所述检测模块判断电池是否已对外放电；
    所述实际剩余电量第一计算模块在所述电池无对外放电时，根据所述当前自耗电率实时计算所述电池的实际剩余电量；所述时间计算模块在电池无对外放电时，记录待补电时长，并判断所述待补电时长是否大于等于所述预设补电期限；所述检测模块还判断所述电池是否与外接电源连接；所述控制模块还在所述待补电时长大于等于所述预设补电期限且所述电池连接外接电源时，使所述电池自动充电；所述实际剩余电量第一判断模块判断所述电池是否充电到所述目标电量；所述控制模块还在所述电池充电到所述目标电量后，使所述电池结束自动充电；所述检测模块还判断电池自动充电前是否已对外放电；
    所述实际剩余电量第二计算模块在所述电池已对外放电时，根据安时计量法和所述当前自耗电率实时计算所述电池的实际剩余电压。
  10. 根据权利要求9所述的一种常带电自保养的电池，其特征在于：
    所述电池还包括预警单元；
    所述BMS单元还包括实际剩余电量第二判断模块和完全放电判断模块；
    所述实际剩余电量第二判断模块在所述电池不连接外接电源时，判断所述电池的实际剩余电量是否降至预警电量以下；
    所述完全放电判断模块判断电池是否已完全放电；
    所述预警单元在所述电池的实际剩余电量降至预警电量以下时发送预警信号。
PCT/CN2022/082537 2022-02-24 2022-03-23 一种电池常带电自保养的控制方法及常带电自保养的电池 WO2023159708A1 (zh)

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