WO2023184390A1 - 电化学装置及其充电方法、电子装置 - Google Patents

电化学装置及其充电方法、电子装置 Download PDF

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WO2023184390A1
WO2023184390A1 PCT/CN2022/084536 CN2022084536W WO2023184390A1 WO 2023184390 A1 WO2023184390 A1 WO 2023184390A1 CN 2022084536 W CN2022084536 W CN 2022084536W WO 2023184390 A1 WO2023184390 A1 WO 2023184390A1
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Prior art keywords
charging
stage
current
voltage
cut
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PCT/CN2022/084536
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English (en)
French (fr)
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刘云启
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东莞新能安科技有限公司
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Priority to CN202280004899.7A priority Critical patent/CN115843396A/zh
Priority to PCT/CN2022/084536 priority patent/WO2023184390A1/zh
Publication of WO2023184390A1 publication Critical patent/WO2023184390A1/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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • 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
    • 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

  • Embodiments of the present application relate to the field, and in particular, to an electrochemical device and a charging method thereof, as well as an electronic device including an electrochemical device.
  • Lithium batteries have the advantages of good rate performance, high voltage, light weight, long cycle life, and no memory effect. They have been widely used in consumer products, digital products, power products, medical and security and other fields. How to charge lithium batteries is one of the key technologies in lithium battery applications. Lithium batteries using lithium iron phosphate system have long cycle life and good stability, but have poor low-temperature performance and cannot take into account both low-temperature and high-temperature applications. Lithium batteries of the lithium iron phosphate system are usually prohibited from charging at low temperatures, or the low-temperature charging rate of lithium iron phosphate batteries is set to 0.1C or even lower, and the charging time is longer, even more than 10 hours. Due to the limited endurance capacity of the electrochemical device, if the charging rate is blindly increased, charging at an excessive rate will cause lithium precipitation in the negative electrode, and even cause the electrochemical device to short-circuit, catch fire, and explode, causing certain safety hazards.
  • embodiments of the present application provide an electrochemical device and its charging method, a computer storage medium, and an electronic device including an electrochemical device to at least partially solve the above problems and improve the charging of lithium iron phosphate batteries at low temperatures. efficiency.
  • the charging current in the (i)-th sub-stage is smaller than the first charging current and greater than the charging current in the (i+1)-th sub-stage; in the third charging stage, the second charging current is used to charge the electrochemical The device is charged to a second cut-off voltage, and the second charging current is less than the N-th sub-stage charging current; and in the fourth charging stage, the electrochemical device is charged to a third cut-off voltage with a third charging current, so The third charging current is smaller than the second charging current.
  • the third cut-off voltage is greater than the second cut-off voltage
  • the second cut-off voltage is greater than the first cut-off voltage.
  • the controller in response to the current temperature being greater than the reference temperature, is further configured to cause the charging module to charge the electrochemical device in a plurality of constant current charging stages, the plurality of constant current charging stages.
  • the charging current in the charging stage gradually decreases, and the cut-off voltages of the multiple constant current charging stages gradually increase.
  • the reference temperature is a temperature value in a range of 10°C to 25°C.
  • the charging method ends when the electrochemical device is charged to the third cut-off voltage.
  • the electrochemical device further includes a memory configured to store the first cut-off voltage, the second cut-off voltage, the third cut-off voltage, the first charging current, the second charging current, and the third cut-off voltage. Three charging currents and sub-stage charging currents of N sub-stages of the second charging stage.
  • a charging method of an electrochemical device includes: determining whether the current temperature is less than a reference temperature; and in response to the current temperature being less than the reference temperature, charging the electrochemical device in the following manner:
  • the charging current in the (i)-th sub-stage is smaller than the first charging current and greater than the charging current in the (i+1)-th sub-stage; in the third charging stage, the second charging current is used to charge the electrochemical The device is charged to a second cut-off voltage, and the second charging current is less than the N-th sub-stage charging current; and in the fourth charging stage, the electrochemical device is charged to a third cut-off voltage with a third charging current, so The third charging current is smaller than the second charging current.
  • the third cut-off voltage is greater than the second cut-off voltage, and the second cut-off voltage is greater than the first cut-off voltage.
  • the charging method further includes: in response to the current temperature being greater than the reference temperature, charging the electrochemical device through a plurality of constant current charging stages, wherein the charging of the plurality of constant current charging stages The current gradually decreases, and the cut-off voltages of the multiple constant current charging stages gradually increase.
  • the reference temperature is a temperature value in a range of 10°C to 25°C.
  • the charging method ends when the electrochemical device is charged to the third cut-off voltage.
  • a computer storage medium has computer instructions that, when run on a controller of the electrochemical device, cause the electrochemical device to perform the charging method of the second aspect.
  • an electronic device including the electrochemical device of the first aspect.
  • the charging mode is determined according to the current temperature.
  • a larger charging current is used to charge the electrochemical device in the first charging stage.
  • Constant current charging is performed.
  • multiple sub-stage constant current charging methods are used to charge the electrochemical device.
  • the charging currents of the multiple sub-charging stages of the second charging stage decrease, and the multiple sub-stages have the same cut-off voltage (with The cut-off voltage in the first charging stage is the same), in the third charging stage and the fourth charging stage, a smaller charging current is used to perform constant current charging of the electrochemical device, and the cut-off voltage is increased.
  • the charging time of the third and fourth charging stages is shortened, and the potential of the positive electrode plate can be more effectively controlled to avoid lithium deposition. It also effectively reduces the safety risks of the battery charging process and is suitable for charging lithium batteries at low temperatures.
  • Figure 1 is a schematic block diagram of an electrochemical device according to an embodiment of the present application.
  • Figure 2 shows the charging parameter lookup table in the memory.
  • FIG. 3 is a flow chart of the charging method of the electrochemical device according to the embodiment of the present application.
  • Figure 4 shows the relationship between battery voltage, charging current and capacitance during charging.
  • Figure 5 shows the battery voltage and charging current during charging.
  • Figure 6 shows a comparison of the charging time between the charging method and the constant current and constant voltage charging method according to the embodiment of the present application.
  • Figure 7 shows the battery voltage comparison and the anode lithium potential comparison between the charging method and the constant current and constant voltage charging method according to the embodiment of the present application.
  • Figure 8 shows the battery core after 10 cycles of charging and discharging according to the charging method of the present application at -20°C.
  • 9A and 9B illustrate battery voltage comparisons and charging time comparisons between the charging method of the embodiment of the present application and the charging method of the related art.
  • Figures 10A and 10B show the battery voltage comparison and the positive electrode plate versus lithium potential comparison between the charging method of the embodiment of the present application and the charging method of the related art.
  • the embodiments mentioned herein can be combined with each other to form new technical solutions.
  • all technical features mentioned herein can be combined with each other to form new technical solutions.
  • the numerical range “a to b” represents any real number between a and b.
  • the numerical range “6 to 22” means that all real numbers between “6 to 22" have been listed in this article, and "6 to 22" is just an abbreviation of these numerical combinations.
  • the constant current and constant voltage (CC-CV) charging method in the related art first uses a constant current for charging.
  • the state of charge of the battery core increases, the internal polarization of the battery core gradually increases, and the anode has a negative impact on the lithium battery.
  • the potential has been decreasing.
  • lithium precipitation potential lithium ions will precipitate at the anode, causing irreversible lithium loss (capacity loss) and causing serious safety hazards.
  • the charging time is long, the current remains basically unchanged throughout the charging cycle, and the charging efficiency is low.
  • the staged charging method in the related art regulates based on the cut-off voltage.
  • the charging current is switched to proceed to the next stage of charging.
  • the cut-off voltage increases step by step and the charging current decreases step by step.
  • the charging current is large, the internal polarization is large, and the actual charging capacity of the battery is low, which will make subsequent low-current charging time longer and the overall charging time longer.
  • FIG. 1 is a schematic block diagram of an electrochemical device according to an embodiment of the present application.
  • the electrochemical device 10 includes: a battery cell 100 , a controller 200 , a charging module 300 , a discharging module 400 , a temperature sensor 500 and a memory 600 .
  • Cells are also called batteries.
  • the battery core 100 includes: a positive electrode piece, a negative electrode piece, an electrolyte, and a separator disposed between the positive electrode piece and the negative electrode piece.
  • the positive electrode piece is a lithium compound, such as lithium iron phosphate (LiFePO4).
  • the negative electrode piece is graphite.
  • the charging module 300 is used to charge the electrochemical device 10 , that is, to charge the battery core 100 .
  • the charging module 300 may be connected to an external charging device (such as a charger).
  • the discharge module 400 is connected to an external load and is used to discharge the electrochemical device 10 , that is, the battery core 100 supplies power to the load.
  • the discharge module 400 includes, for example, a DC-DC converter and a DC-AC converter.
  • the controller 200 is used to control the working modes of the charging module 300 and the discharging module 400 , for example, controlling the method of charging the electrochemical device 10 by the charging module 300 .
  • the controller 200, the charging module 300 and the discharging module 400 may also be called a battery management system.
  • the temperature sensor 500 is used to sense the ambient temperature.
  • the memory 600 is used to store codes corresponding to charging methods, charging parameters, etc.
  • Electrochemical device 10 also includes current sensors and voltage sensors. The current sensor is used to monitor the charging current and discharging current of the battery cell 100 .
  • the voltage sensor is used to monitor the voltage of the battery cell 100 .
  • FIG. 3 is a flow chart of the charging method of the electrochemical device according to the embodiment of the present application.
  • This charging method can be used to charge the electrochemical device 10 shown in FIG. 1 .
  • Figure 4 shows the relationship between battery voltage, charging current and capacitance during charging.
  • the horizontal axis of Figure 4 represents the state of charge achieved at each charging stage during the charging process.
  • the vertical axis on the left side of Figure 4 is the voltage of the battery cell 100, and the vertical axis on the right side is the charging current.
  • Figure 4 shows curve 1 and curve 2.
  • Curve 1 in Figure 5 is the change in voltage of the battery cell 100 during the charging process.
  • Curve 2 in Figure 5 shows the magnitude of the charging current at each stage during the charging process.
  • the state of charge (SOC) represents the state of available electrical energy in the battery cell, usually expressed as a percentage.
  • Charging current is usually expressed by charging rate, which is an expression of charging current relative to battery capacity.
  • Battery capacity is generally expressed in Ah or mAh. For example, when the battery capacity is 1200mAh, the charging current of 1C is 1200mA, and the charging current of 0.2C is equal to 240mA.
  • the charging method includes the following steps.
  • Step S301 obtain the current temperature.
  • the temperature sensor 500 senses the current temperature and sends the current temperature to the controller 200 .
  • Step S302 determine whether the current temperature is lower than the reference temperature.
  • the reference temperature is a temperature value in the range of 10°C to 25°C.
  • the reference temperature is determined according to the material of the battery core 100 .
  • the positive electrode piece is lithium iron phosphate, and the reference temperature is 25°C.
  • the controller 200 controls the charging module 300 to charge the battery core 100 according to the method of steps S303 to S306.
  • the controller 200 searches the memory 600 for the charging parameters corresponding to the current temperature according to the current temperature, and the charging module 300 charges the battery core 100 according to the charging parameters corresponding to the current temperature.
  • Step S303 In the first charging stage, the electrochemical device is charged to the first cut-off voltage V1 with the first charging current.
  • the first charging stage is a constant current charging stage. A larger first charging current is used to charge the cell 100 of the electrochemical device, so that the voltage (battery voltage) and SOC of the cell 100 increase quickly.
  • the first charging current I1 is used to perform constant current charging on the battery core 100 .
  • the charging cut-off voltage of the first charging stage P1 is the first cut-off voltage V1.
  • the voltage of the battery cell 100 is monitored through a voltage sensor.
  • the first charging current I1 can be selected according to the current temperature. In the embodiment shown in Figures 4 and 5, the first charging current I1 is 0.4C, and the first cut-off voltage V1 is 3.49 ⁇ 0.02V.
  • Step S304 In the second charging stage, the electrochemical device is charged to the first cut-off voltage V1 in a multi-stage constant current manner.
  • the second charging stage includes N sub-stages in sequence, each sub-stage corresponds to a charging current, and N is a positive integer.
  • the electrochemical device In the (i)-th sub-stage charging current, In the i+1) sub-stage, the electrochemical device is charged with a constant current to the first cut-off voltage V1 with the (i+1)-th sub-stage charging current, and the (i)-th sub-stage charging current is less than the first The charging current is greater than the (i+1)th sub-stage charging current.
  • the cut-off voltages of multiple sub-stages in the second charging stage are all the first cut-off voltage V1. In each sub-stage, when the voltage of the battery cell 100 rises to the first cut-off voltage V1, the sub-charging stage ends.
  • Figures 4 and 5 include five sub-stages with the second charging stage P2.
  • the first sub-stage charging current I P21 is used to charge the electrochemical device.
  • the voltage of the battery cell 100 rises to the first cut-off voltage V1
  • the first sub-stage ends and the second sub-stage is entered. stage.
  • the second sub-stage charging current IP22 the third sub-stage charging current IP23
  • the fourth sub-stage charging current IP24 the fifth sub-stage are used respectively.
  • the sub-stage charging current I P25 charges the electrochemical device. As shown in Figure 4, through the second charging stage, the SOC of the electrochemical device is charged to more than 40%.
  • the sub-stage charging current of the second charging stage ranges from 0.35C to 0.15C.
  • the first sub-stage charging current IP21 is 0.35C
  • the second sub-stage charging current IP22 is 0.3C
  • the third sub-stage charging current IP23 is 0.25C
  • the third sub-stage charging current IP23 is 0.25C.
  • the charging current I P24 of the 4th sub-stage is 0.2C
  • the charging current I P25 of the 5th sub-stage is 0.15C.
  • Step S305 in the third charging stage, charge the electrochemical device to the second cut-off voltage V2 with a second charging current, and the second charging current I2 is less than the Nth sub-stage charging current I P2N in the second charging stage,
  • the second cut-off voltage V2 is greater than the first cut-off voltage V1.
  • the electrochemical device in the third charging stage P3, the electrochemical device is charged to the second cut-off voltage V2 using the second charging current I2.
  • the second charging current I2 is 0.1C
  • the second cut-off voltage V2 is 3.55 ⁇ 0.02V.
  • Step S306 In the fourth charging stage, the electrochemical device is charged with the third charging current to the third cut-off voltage V3, the third charging current I3 is less than the second charging current I2, and the third cut-off voltage V3 is greater than the second cut-off voltage. V2. As shown in Figures 4 and 5, in the fourth charging stage P4, the third charging current I3 is used to charge the electrochemical device to the third cut-off voltage V3. In the embodiment shown in FIG. 4 and FIG. 5 , the third charging current I3 is 0.05C, and the third cut-off voltage V3 is 3.6 ⁇ 0.02V.
  • the charging parameters stored in the memory 600 include: the first cut-off voltage V1, the second cut-off voltage V2, the third cut-off voltage V3, the first charging current I1, the second charging current I2, the third charging current I3 and the second charging
  • the sub-stage charging current of the N sub-stages of the stage IP21 to IP2N ).
  • Charging parameters are stored in memory 600 in the form of a look up table. As shown in FIG. 2 , n lookup tables LUT1 to LUTn are stored in the memory 600 . Each lookup table corresponds to a temperature. The charging parameter values corresponding to different temperatures may be different. For example, the lower the temperature, the smaller the first cut-off voltage V1 and the first charging current I1.
  • the controller 200 obtains the lookup table corresponding to the current temperature from the memory 600 and determines the charging parameters.
  • the first cut-off voltage, the second cut-off voltage and the third cut-off voltage can be determined according to the rated voltage of the battery core 100 and do not change with temperature.
  • one or more charging stages may also be included between the third charging stage and the fourth charging stage, the charging current of the one or more charging stages gradually decreases, and the charging current of the one or more charging stages is smaller than that of the third charging stage.
  • the second charging current is greater than the third charging current, the cut-off voltages of these charging stages gradually increase, and the cut-off voltages of these charging stages are greater than the second cut-off voltage and smaller than the third cut-off voltage.
  • the voltage of the battery cell 100 is detected by the voltage sensor.
  • the detection value of the voltage sensor reaches the cut-off voltage, the next charging stage or charging sub-stage is entered.
  • the voltage value detected by the voltage sensor is the sum of the voltage of the battery cell 100 and the voltage on the charging equivalent resistance. Therefore, when entering the next charging stage or charging sub-stage and reducing the charging current, the detection value of the voltage sensor decreases.
  • the controller 200 controls the charging module 300 to charge the electrochemical device in a plurality of constant current charging stages, and the charging current in the multiple constant current charging stages gradually decreases. small, the cut-off voltages of the multiple constant current charging stages gradually increase.
  • the charging currents and cut-off voltages of the multiple constant current charging stages are also stored in the memory 600 .
  • the charging efficiency and charging safety of the electrochemical device can be improved. Electrochemical devices can be charged quickly and safely even in low-temperature environments. Furthermore, in the first charging stage, a larger charging current is used for constant current charging of the battery cell, and in the second charging stage, multiple sub-stages are used for constant current charging, and the cut-off voltages of the multiple sub-stages are also configured as the first cut-off voltage, which enables At the end of the second charging stage, the actual voltage of the battery cell is closer to the first cut-off voltage, shortening the time of the third and fourth charging stages.
  • the charging current used in the first charging stage is larger, at the end of the first charging stage, the voltage on the charging equivalent resistor is larger, and the difference between the actual voltage of the battery cell and the first cut-off voltage is larger.
  • the actual voltage of the battery cell is closer to the first cut-off voltage.
  • the charging current in the third and fourth charging stages is reduced and the cut-off voltage is increased. Furthermore, as the SOC of the battery core increases, the voltage of the battery core increases, and the potential of the positive electrode plate decreases.
  • the same first cut-off voltage as that of the first charging stage is used, so that the potential of the positive electrode piece can be more effectively controlled, avoiding lithium deposition, and effectively reducing the safety of the battery charging process. Risk, suitable for charging lithium batteries at low temperatures.
  • the above charging method is executed by the controller 200 controlling the charging module 300 .
  • the controller 200 is, for example, a microcontroller unit (Microcontroller Unit, MCU), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), etc.
  • the memory 600 may be a non-volatile memory, such as a read-only memory (Read-Only Memory, ROM).
  • the above charging method is stored in the memory 600 in the form of code, and the controller 200 executes the code to control the charging module 300 to perform the above charging method. For example, the controller 200 determines whether to enter the next charging stage or charging sub-stage according to the detection value of the voltage sensor. When the detection value of the voltage sensor is the cut-off voltage, the controller 200 sends a control signal to the charging module 300, and the charging module 300 reduces the charging current.
  • the controller 200 is not necessarily provided inside the electrochemical device 10 .
  • the controller 200 may be provided within a charging device or load connected to the electrochemical device. And communicates with the charging module 300 of the electrochemical device 10 to control the charging module 300 to charge the electrochemical device 10 .
  • the constant current and constant voltage charging method and the charging method of the present application were respectively used to charge the positive electrode plate including lithium iron phosphate at -20°C.
  • the battery cells are used for charging experiments.
  • Figure 6 shows a comparison of the charging time between the charging method and the constant current and constant voltage charging method according to the embodiment of the present application.
  • the constant current and constant voltage charging method takes about 5.5 hours, while using the charging method of this application, it only takes less than 4 hours;
  • the constant current and constant voltage charging method takes about 250 minutes, but using the charging method of this application, it only takes about 150 minutes, saving 100 minutes, which greatly reduces the charging time. , improving the overall charging performance.
  • Figure 7 shows the battery voltage comparison and the anode lithium potential comparison between the charging method and the constant current and constant voltage charging method according to the embodiment of the present application.
  • Figure 7 includes curve 1, curve 2, curve 3 and curve 4.
  • Curve 1 is the change curve of battery voltage during the charging process of the electrochemical device using the charging method of the present application.
  • Curve 2 is the change curve of the battery voltage during the charging process of the electrochemical device using the constant current and constant voltage charging method.
  • Curve 3 is the change curve of the lithium potential of the positive electrode plate during the charging process of the electrochemical device using the charging method of the present application.
  • Curve 4 is the change curve of the lithium potential of the positive electrode plate during the charging process of the electrochemical device using the constant current and constant voltage charging method.
  • Figure 8 shows a disassembled view of a battery cell whose positive electrode plate includes lithium iron phosphate after 10 charge-discharge cycles at -20°C according to the charging method of the present application. As shown in Figure 7, the interface of the negative electrode plate is good and no lithium precipitation occurs.
  • the applicant used the step charging method in the related art and the charging method of the present application to charge the positive electrode plate including lithium iron phosphate at -10°C.
  • the battery cells are used for charging experiments.
  • the electrochemical device is charged through multiple stages, the charging current used in the multiple stages gradually decreases, and the cut-off voltage of the multiple stages gradually increases.
  • the number of charging stages in the stage charging method in the related art is 8, and the cut-off voltages from the first constant current charging stage to the eighth constant current charging stage are V11, V21,...V81 respectively, V81>V71>...>V21> V11.
  • the second charging stage includes 5 sub-stages.
  • Figure 9A shows a comparison of battery voltages between the two charging methods
  • Figure 9B shows a comparison of the charging times of the two charging methods
  • Figure 9A shows curve 1 and curve 2.
  • Curve 1 is the curve of the battery voltage during the charging process of the electrochemical device using the charging method of the present application.
  • Curve 2 is the curve of the battery voltage during the charging process of the electrochemical device using the stage charging method in the related art. Battery voltage curve.
  • Figure 9A using the charging method of the present application, the battery SOC is charged to about 80% in the second charging stage.
  • Figure 9B shows curve 3 and curve 4.
  • Curve 3 is the relationship between cell SOC and time when the electrochemical device is charged using the charging method of the present application.
  • Curve 4 is the charging of the electrochemical device using the stage charging method of the related technology.
  • the charging method of the present application is more than 2 hours faster than the stage charging method of the related art. This is because in the stage charging method in the related art, a constant large current is used to charge the battery core in the first charging stage, which will cause the internal polarization of the battery core to be larger and the actual charging voltage of the battery core to be smaller (much smaller than the first charging stage). cut-off voltage of each charging stage), resulting in a longer duration of subsequent charging stages, and ultimately a longer total charging time. Therefore, the charging method of the present application has higher charging efficiency.
  • the electrochemical device is charged through multiple stages, and the charging current used in the multiple stages is gradually reduced.
  • the number of charging stages in the multi-stage charging method is 8.
  • the cut-off voltage of the first constant current charging stage is V11
  • the second to sixth constant current charging stages use the same cut-off voltage of V21
  • the 7th constant current charging stage uses the same cut-off voltage of V21.
  • the cut-off voltage V31 is used in the charging stage
  • the cut-off voltage V41 is used in the eighth charging stage, V41>V31>V21>V11.
  • the second charging stage includes 5 sub-stages.
  • Figure 10A shows the comparison of battery voltages between the two charging methods
  • Figure 10B shows the comparison of the positive electrode plate versus lithium potential of the two charging methods
  • Figure 10A shows curve 1 and curve 2.
  • Curve 1 is the curve of the battery voltage during the charging process of the electrochemical device using the charging method of the present application.
  • Curve 2 is the curve of the battery voltage during the charging process of the electrochemical device using the stage charging method in the related art. Battery voltage curve.
  • the cell SOC is charged to slightly greater than 60% in the second charging stage. As shown in FIG.
  • the cut-off voltage of the first charging stage in the charging method of the present application is 0.07V lower than the cut-off voltage V11 of the first stage of the staged charging method in the related art.
  • Figure 9B shows curve 3 and curve 4.
  • Curve 3 is the relationship curve between the cell SOC and the positive electrode plate versus lithium potential using the charging method of the present application to charge the electrochemical device.
  • Curve 4 is the stage charging method using related technologies. The relationship curve between the SOC of the battery cell and the lithium potential of the positive electrode for charging the electrochemical device.
  • the electrochemical device is charged using the staged charging method of the related technology.
  • the SOC of the battery cell is between 60% and 90%, lithium precipitation occurs; using the charging method of this application, no lithium precipitation occurs during this charging process. Lithium precipitation. Therefore, the charging method of the present application has higher reliability.
  • the charging method of the present application can not only improve the charging efficiency, but also avoid lithium precipitation.
  • the present application also provides a non-transitory computer storage medium.
  • the non-transitory computer storage medium has computer instructions. When the computer instructions are run on the controller 200 of the electrochemical device 10, the electrochemical device 10 is caused to perform the above charging method.
  • Non-transitory computer storage media include, but are not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (Electrically Erasable Programmable Read Only Memory, EEPROM), flash memory, Compact Disc Read-Only Memory (CD-ROM), Digital VideoDisc (DVD) or other optical disk storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage device .
  • the present application also provides an electronic device, which includes the electrochemical device in any of the preceding embodiments. Electrochemical devices are used to power electronic devices.
  • the electrochemical device provided by this application can be quickly charged in a low-temperature environment, ensuring the battery life of the electronic device.
  • Electronic devices of this application include, but are not limited to: notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headsets, video recorders, LCD televisions, Portable cleaners, portable CD players, mini CDs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, lighting equipment, toys, Game consoles, clocks, power tools, flashlights, cameras, large household batteries, lithium-ion capacitors.
  • the electrochemical device of the present application is also suitable for energy storage power stations, maritime vehicles, and air vehicles.
  • Air transport devices include air transport devices within the atmosphere and air transport devices outside the atmosphere.
  • the charging mode is determined according to the current temperature.
  • a larger charging current is used to charge the electrochemical device in the first charging stage.
  • Constant current charging is performed.
  • multiple sub-stage constant current charging methods are used to charge the electrochemical device.
  • the charging currents of the multiple sub-charging stages of the second charging stage decrease, and the multiple sub-stages have the same cut-off voltage (with The cut-off voltage in the first charging stage is the same), in the third charging stage and the fourth charging stage, a smaller charging current is used to perform constant current charging of the electrochemical device, and the cut-off voltage is increased.
  • the charging time of the third and fourth charging stages is shortened, and the potential of the positive electrode plate can be more effectively controlled to avoid lithium deposition. It also effectively reduces the safety risks of the battery charging process and is suitable for charging lithium batteries at low temperatures.

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Abstract

一种电化学装置及其充电方法。充电方法包括：响应于当前温度小于参考温度，在第一充电阶段以第一充电电流进行恒流充电至第一截止电压；在第二充电阶段以多阶段恒流方式充电；在第三充电阶段以第二充电电流进行恒流充电至第二截止电压；在第四充电阶段以第三充电电流充电至第三截止电压。第二充电阶段包括多个充电截止电压为第一截止电压的子阶段。第一截止电压小于第二截止电压，第二截止电压小于第三截止电压。第一充电电流大于第二充电阶段的子阶段充电电流，第二充电阶段的子阶段充电电流大于第二充电电流，第二充电电流大于第三充电电流。该充电方法适用于低温下充电，避免发生析锂，充电效率高。

Description

电化学装置及其充电方法、电子装置 技术领域
本申请实施例涉及领域，尤其涉及一种电化学装置及其充电方法、以及包括电化学装置的电子装置。
背景技术
锂电池具有倍率性能好，电压高、重量轻、循环寿命长、无记忆效应的优点，已经广泛应用于消费类产品、数码类产品、动力产品、医疗及安防等领域。如何对锂电池进行充电是锂电池应用中的关键技术之一。采用磷酸铁锂体系的锂电池的循环寿命长、稳定性能好，但是低温性能差，不能很好的兼顾低温与高温应用。磷酸铁锂体系的锂电池通常被禁止在低温下进行充电，或者磷酸铁锂电池的低温充电倍率设置为0.1C甚至更低，充电时间较长，甚至可达到10h以上。由于电化学装置承受能力有限，如果盲目提高充电倍率，过大倍率充电会造成负极析锂，甚至导致电化学装置短路，起火，爆炸，造成一定的安全隐患。
发明内容
有鉴于此，本申请实施例提供一种电化学装置及其充电方法、计算机存储介质以及一种包括电化学装置的电子装置，以至少部分解决上述问题，提高磷酸铁锂电池在低温下的充电效率。
根据本申请实施例的第一方面，提供了一种电化学装置。电化学装置与控制器连接，响应于当前温度小于参考温度，所述控制器被配置为：为判断当前温度是否小于参考温度，响应于当前温度小于所述参考温度，控制器使充电模块通过以下方式对电化学装置充电。在第一充电阶段，以第一充电电流对所述电化学装置充电至第一截止电压；在第二充电阶段，以多阶段恒流方式对所述电化学装置充电，其中，所述第二充电阶段包括依序的N个子阶段，N为正整数；在第(i)子阶段(i＝1、2、…、N-1)，以第(i)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，在第(i+1)子阶段，以第(i+1)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，所述第(i)子阶段充电电流小于所述第一充电电流，大于所述第(i+1)子阶段充电电流；在第三充电阶段，以第二充电电流对所述电化学装置充电至第二截止电压，所述第二充电电流小于所述第N子阶段充电电流；以及在第四充电阶段，以第三充电电流对所述电化学装置充电至第三截止电压，所述第三充电电流小于所述第二充电电流。其中，所述第三截止电压大于所述第二截止电压，所述第二截止电压大于所述第一截止电压。
在一些实施例中，响应于当前温度大于所述参考温度，所述控制器还被配置为使所述充电模块以多个恒流充电阶段对所述电化学装置充电，所述多个恒流充电阶段的充电电流逐渐减小，所述多个恒流充电阶段的截止电压逐渐增大。
在一些实施例中，所述参考温度为10℃至25℃中的温度值。
在一些实施例中，当所述电化学装置充电到所述第三截止电压，所述充电方法结束。
在一些实施例中，所述当前温度越低，所述第一截止电压和第一充电电流越小。
在一些实施例中，所述电化学装置还包括存储器，所述存储器被配置为存储所述第一截止电压、第二截止电压、第三截止电压、第一充电电流、第二充电电流、第三充电电流以及所述第二充电阶段的N个子阶段的子阶段充电电流。
在一些实施例中，所述电芯包括正极极片，所述正极极片包括磷酸铁锂。
根据本申请实施例的第二方面，提供了一种电化学装置的充电方法。充电方法包括：判断当前温度是否小于参考温度；以及响应于当前温度小于所述参考温度，通过以下方式对所述电化学装置充电：
在第一充电阶段，以第一充电电流对所述电化学装置充电至第一截止电压；在第二充电阶段，以多阶段恒流方式对所述电化学装置充电，其中，所述第二充电阶段包括依序的N个子阶段，N为正整数；在第(i)子阶段(i＝1、2、…、N-1)，以第(i)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，在第(i+1)子阶段，以第(i+1)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，所述第(i)子阶段充电电流小于所述第一充电电流，大于所述第(i+1)子阶段充电电流；在第三充电阶段，以第二充电电流对所述电化学装置充电至第二截止电压，所述第二充电电流小于所述第N子阶段充电电流；以及在第四充电阶段，以第三充电电流对所述电化学装置充电至第三截止电压，所述第三充电电流小于所述第二充电电流。
其中，所述第三截止电压大于所述第二截止电压，所述第二截止电压大于所述第一截止电压。
在一些实施例中，所述充电方法还包括：响应于当前温度大于所述参考温度，通过多个恒流充电阶段对所述电化学装置充电，其中，所述多个恒流充电阶段的充电电流逐渐减小，所述多个恒流充电阶段的截止电压逐渐增大。
在一些实施例中，所述参考温度为10℃至25℃中的温度值。
在一些实施例中，当所述电化学装置充电到所述第三截止电压，所述充电方法结束。
在一些实施例中，所述当前温度越低，所述第一截止电压和第一充电电流越小。
根据本申请实施例的第三方面，提供了一种计算机存储介质。所述计算机存储介质有计算机指令，当所述计算机指令在电化学装置的控制器上运行时，使得所述电化学装置执行如第二方面的充电方法。
根据本申请实施例的第四方面，提供了一种电子装置，包括第一方面的电化学装置。
根据本申请实施例提供的电化学装置及其充电方法、计算机存储介质以及电子装置，按照当前温度确定充电方式，当温度小于参考温度时，在第一充电阶段使用较大充电电流对电化学装置进行恒流充电，在第二充电阶段使用多个子阶段恒流充电方式对电化学装置进行充电，第二充电阶段的多个子充电阶段的充电电流递减，并且多个子阶段具有相同的截止电压(与第一充电阶段的截止电压相同)，在第三充电阶段和第四充电阶段 使用更小的充电电流对电化学装置进行恒流充电，并增大截止电压。通过设置第一充电阶段和第二充电阶段的多个子阶段具有相同的截止电压，缩短了第三和第四充电阶段的充电时间，并且能够更有效的控制正极极片的电位，避免析锂，并且有效降低电池充电过程的安全风险，适合低温下的锂电池充电。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请实施例中记载的一些实施例，对于本领域普通技术人员来讲，还可以根据这些附图获得其他的附图。
图1是本申请实施例的电化学装置的示意框图。
图2示出了存储器中的充电参数查找表。
图3是本申请实施例的电化学装置的充电方法的流程图。
图4示出了充电过程中的电池电压和充电电流和电容量的关系。
图5示出了充电过程中的电池电压和充电电流。
图6示出了本申请实施例的充电方法和恒流恒压充电方法的充电时长对比。
图7示出了本申请实施例的充电方法和恒流恒压充电方法的电池电压对比和阳极对锂电位的对比。
图8示出了-20℃下按照本申请的充电方法充电放电循环10次后的电芯。
图9A和9B示出了本申请实施例的充电方法和相关技术的充电方法的电池电压对比和充电时间对比。
图10A和10B示出了本申请实施例的充电方法和相关技术的充电方法的电池电压对比和正极极片对锂电位对比。
具体实施方式
为了使本领域的人员更好地理解本申请实施例中的技术方案，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请实施例一部分实施例，而不是全部的实施例。基于本申请实施例中的实施例，本领域普通技术人员所获得的所有其他实施例，都应当属于本申请实施例保护的范围。
需要说明的是：本发明中，如果没有特别的说明，本文所提到的实施例可以相互组合形成新的技术方案。本发明中，如果没有特别的说明，本文所提到的所有技术特征可以相互组合形成新的技术方案。本发明中，除非有其他说明，数值范围“a至b”表示a到b之间的任意实数。例如数值范围“6至22”表示本文中已经全部列出了“6至22”之间的全部实数，“6至22”只是这些数值组合的缩略表示。
相关技术中的恒流恒压(CC-CV)充电方法，首先使用恒定电流进行充电，随着充电的进行，电芯的荷电状态升高，电芯内部极化逐渐增大，阳极对锂电位一直在降低，到达析锂电位时，锂离子会在阳极析出，造成不可逆锂的损失(容量损失)，且造成严重 的安全隐患。此外，充电时间较长，整个充电周期电流基本维持不变，充电效率低下。
相关技术中的阶段充电方法，依据截止电压进行调控，到达设定截止电压时切换充电电流，进行下一阶段的充电，截止电压逐阶段升高、充电电流逐阶段降低。在前期若干阶段，充电电流较大，内部极化较大，电池实际充电容量较低，会使后续小电流充电时间长，总体充电时间较长。
图1是本申请实施例的电化学装置的示意框图。如图1所示，电化学装置10包括：电芯100、控制器200、充电模块300、放电模块400、温度传感器500和存储器600。电芯也称为电池。电芯100包括：正极极片、负极极片、电解液以及设置在正极极片和负极极片之间的隔膜。正极极片为锂化合物，例如磷酸铁锂(LiFePO4)。负极极片为石墨。电化学装置10充电时，在电场作用下，锂离子从正极极片脱嵌，嵌入到负极极片，存储能量。电化学装置10放电时，锂离子从负极极片脱嵌，流向正极极片，使正极极片处于富锂状态，这个过程形成电流。充电模块300用于实现电化学装置10的充电，即对电芯100充电。充电模块300可以与外部充电装置(例如充电器)连接。放电模块400与外部负载连接，用于实现电化学装置10的放电，即电芯100为负载供电。放电模块400例如包括直流-直流转换器和直流-交流转换器。控制器200用于控制控制充电模块300和放电模块400的工作模式，例如控制充电模块300对电化学装置10充电的方法。控制器200、充电模块300和放电模块400也可称为电池管理系统。温度传感器500用于感测环境温度。存储器600用于存储充电方法对应的代码，充电参数等。电化学装置10还包括电流传感器和电压传感器。电流传感器用于监测电芯100的充电电流和放电电流。电压传感器用于监测电芯100的电压。
图3是本申请实施例的电化学装置的充电方法的流程图。该充电方法可用于对图1所示的电化学装置10进行充电。图4示出了充电过程中的电池电压和充电电流和电容量的关系。图4的横轴代表了充电过程中各充电阶段达到的荷电状态。图4左侧的纵轴为电芯100的电压，右侧的纵轴为充电电流。图4示出了曲线1和曲线2。图5的曲线1是充电过程中的电芯100的电压的变化。图5的曲线2是充电过程中各阶段的充电电流的大小。荷电状态(state of charge，SOC)表征电芯中可用电能的状态，通常以百分比来表示。充电电流通常用充电倍率表示，充电倍率是充电电流相对于电池容量的一种表示。电池容量一般用Ah或mAh表示。例如电池容量是1200mAh时，1C的充电电流就是1200mA，0.2C的充电电流就等于240mA。
以通过该充电方法将电芯100的SOC从0％充至80％为例，充电方法包括以下步骤。
步骤S301，获取当前温度。温度传感器500感测当前温度，并将当前温度发送给控制器200。
步骤S302，判断当前温度是否小于参考温度。参考温度为10℃至25℃范围中的温度值。例如，参考温度根据电芯100的材料确定。在本实施例中，正极极片为磷酸铁锂，参考温度为25℃。
响应于当前温度小于参考温度，控制器200控制充电模块300按照步骤S303至S306 的方法对电芯100充电。控制器200根据当前温度从存储器600中查找当前温度对应的充电参数，充电模块300根据当前温度对应的充电参数对电芯100充电。
步骤S303，在第一充电阶段，以第一充电电流对电化学装置充电至第一截止电压V1。第一充电阶段是一个恒流充电阶段，使用较大的第一充电电流对电化学装置的电芯100充电，使得电芯100的电压(电池电压)和SOC较快地升高。如图4和图5所示，在第一充电阶段P1，使用第一充电电流I1对电芯100进行恒流充电。第一充电阶段P1的充电截止电压为第一截止电压V1。通过电压传感器监测电芯100的电压。当电芯100的电压升高到第一截止电压V1，结束第一充电阶段，电芯100的SOC到达5％左右。第一充电电流I1可根据当前温度选择。在图4和图5所示的实施例中，第一充电电流I1为0.4C,第一截止电压V1为3.49±0.02V。
步骤S304，在第二充电阶段，以多阶段恒流方式对电化学装置充电至第一截止电压V1。第二充电阶段包括依序的N个子阶段，每个子阶段对应一个充电电流，N为正整数。在第(i)子阶段(i＝1、2、…、N-1)，以第(i)子阶段充电电流对所述电化学装置进行恒流充电至第一截止电压V1，在第(i+1)子阶段，以第(i+1)子阶段充电电流对所述电化学装置进行恒流充电至第一截止电压V1，所述第(i)子阶段充电电流小于所述第一充电电流，大于所述第(i+1)子阶段充电电流。第二充电阶段中的多个子阶段的截止电压都是第一截止电压V1。在每个子阶段，当电芯100的电压升到第一截止电压V1，结束该子充电阶段。图4和图5以第二充电阶段P2包括5个子阶段。在第二充电阶段的第1子阶段，使用第1子阶段充电电流I P21对电化学装置充电，当电芯100的电压升到第一截止电压V1，结束第1子阶段，进入第2子阶段。类似地，在第二充电阶段的第2子阶段至第5子阶段，分别使用第2子阶段充电电流I P22、第3子阶段充电电流I P23、第4子阶段充电电流I P24、第5子阶段充电电流I P25对电化学装置进行充电。如图4所示，通过第二充电阶段，将电化学装置的SOC充至40％以上。在一些实施例中，第二充电阶段的子阶段充电电流的范围是0.35C至0.15C。在图4和图5所示的实施例中，第1子阶段充电电流I P21为0.35C，第2子阶段充电电流I P22为0.3C，第3子阶段充电电流I P23为0.25C，第4子阶段充电电流I P24为0.2C，第5子阶段充电电流I P25为0.15C。
步骤S305，在第三充电阶段，以第二充电电流对所述电化学装置充电至第二截止电压V2，所述第二充电电流I2小于第二充电阶段中第N子阶段充电电流I P2N，所述第二截止电压V2大于所述第一截止电压V1。如图4和5所示，在第三充电阶段P3，使用第二充电电流I2将电化学装置充电至第二截止电压V2。在图4和图5所示的实施例中，第二充电电流I2为0.1C,第二截止电压V2为3.55±0.02V。
步骤S306，在第四充电阶段，以第三充电电流对所述电化学装置充电至第三截止电压V3，第三充电电流I3小于第二充电电流I2，第三截止电压V3大于第二截止电压V2。如图4和图5所示，在第四充电阶段P4，使用第三充电电流I3将电化学装置充电至第三截止电压V3。在图4和图5所示的实施例中，第三充电电流I3为0.05C，第三截止电压V3为3.6±0.02V。
存储器600中存储的充电参数包括：第一截止电压V1、第二截止电压V2、第三截止电压V3、第一充电电流I1、第二充电电流I2、第三充电电流I3以及所述第二充电阶段的N个子阶段的子阶段充电电流(I P21至I P2N)。充电参数以查找表(look up table)的形式存储在存储器600。如图2所示，存储器600中存储n个查找表LUT1至LUTn。每个查找表对应一个温度。不同的温度对应的充电参数取值可能不同。例如，温度越低，第一截止电压V1和第一充电电流I1越小。控制器200从存储器600获取当前温度对应的查找表，确定充电参数。第一截止电压、第二截止电压和第三截止电压可以根据电芯100的额定电压确定，不随温度变化。
应理解，在第三充电阶段和第四充电阶段之间还可以包括一个或多个充电阶段，该一个或多个充电阶段的充电电流逐渐降低，并且一个或多个充电阶段的充电电流小于第二充电电流，大于第三充电电流，这些充电阶段的截止电压逐渐增大，并且这些充电阶段的截止电压大于第二截止电压，小于第三截止电压。
应理解，在充电过程中，通过电压传感器检测电芯100的电压，当电压传感器的检测值到达截止电压，则进入下一充电阶段或充电子阶段。但是电压传感器检测到的电压值是电芯100的电压和充电等效电阻上的电压之和。因此，当进入到下一个充电阶段或充电子阶段，降低充电电流后，电压传感器的检测值降低。
进一步地，响应于在步骤S302判断当前温度大于参考温度，控制器200控制充电模块300按照以多个恒流充电阶段对所述电化学装置充电，该多个恒流充电阶段的充电电流逐渐减小，该多个恒流充电阶段的截止电压逐渐增大。该多个恒流充电阶段的充电电流和截止电压也存储在存储器600中。
首先，通过感测当前温度，根据当前温度确定当前温度对应的充电方法和充电参数，能够提高电化学装置的充电效率和充电安全性。即使在低温环境下，也能快速安全地对电化学装置充电。进一步，在第一充电阶段使用较大充电电流对电芯进行恒流充电，在第二充电阶段使用多子阶段恒流充电，多个子阶段的截止电压也被配置为第一截止电压，能够使第二充电阶段结束时电芯的实际电压更为接近第一截止电压，缩短第三和第四充电阶段的时间。因为第一充电阶段使用的充电电流较大，第一充电阶段结束时，充电等效电阻上电压较大，电芯的实际电压和第一截止电压的差值较大，通过第二充电阶段的多个子阶段的恒流充电，电芯的实际电压更接近第一截止电压。对于第三和第四充电阶段，由于充电电流较小，充电等效电阻上电压较小，电芯的实际电压基本等于第三和第四充电阶段对应的截止电压。为了提高充电效率，第三和第四充电阶段的充电电流减小，截止电压增大。进一步，随着电芯的SOC增大，电芯的电压增大，正极极片的电位减小。在第二充电阶段的子阶段使用和第一充电阶段相同的第一截止电压，使正极极片的电位能够更有效的控制正极极片的电位，避免析锂，并且有效降低电池充电过程的安全风险，适合低温下的锂电池充电。
上述充电方法是控制器200控制充电模块300执行。控制器200例如是微控制器(Microcontroller Unit，MCU)，专用集成电路(Application Specific Integrated  Circuit，ASIC)等。存储器600可以是非易失性存储器，例如只读存储器(Read-Only Memory，ROM)。上述充电方法以代码的形式存储在存储器600中，控制器200执行代码从而控制充电模块300执行上述充电方法。例如，控制器200根据电压传感器的检测值确定是否进入下一个充电阶段或充电子阶段。当电压传感器的检测值为截止电压时，控制器200向充电模块300发送控制信号，充电模块300减小充电电流。
需要说明的是，控制器200不一定设置在电化学装置10内部。例如，控制器200可以设置在与电化学装置连接的充电装置或负载内。并与电化学装置10的的充电模块300通信，控制充电模块300对电化学装置10进行充电。
为了对比本申请的充电方法和相关技术中的恒流恒压充电方法的低温充电性能，分别使用恒流恒压充电方法和本申请的充电方法在-20℃下对正极极片包括磷酸铁锂的电芯进行充电实验。
图6示出了本申请实施例的充电方法和恒流恒压充电方法的充电时长对比。如图6所示，将电芯的SOC从0-0.5％充电到90％，恒流恒压充电方法需要大约5.5小时，而使用本申请的充电方法，只需要不到4个小时；将电芯从SOC从0-0.5％充电到80％，恒流恒压充电方法需要大约250分钟，而使用本申请的充电方法，只需要大约150分钟，节省了100分钟，极大的减少了充电时间,提升了整体充电性能。
图7示出了本申请实施例的充电方法和恒流恒压充电方法的电池电压对比和阳极对锂电位的对比。图7包括曲线1、曲线2、曲线3和曲线4。曲线1是使用本申请的充电方法对电化学装置充电过程中电池电压的变化曲线。曲线2是使用恒流恒压充电方法对电化学装置充电过程中电池电压的变化曲线。曲线3是使用本申请的充电方法对电化学装置充电过程中正极极片对锂电位的变化曲线。曲线4是使用恒流恒压充电方法对电化学装置充电过程中正极极片对锂电位的变化曲线。如图7所示，使用恒流恒压充电方法，随着SOC升高，正极极片电位一直下降并最终到达析锂电位，此时电芯内部发生析锂，造成安全隐患；使用本申请的充电方法，正极极片始终高于析锂电位，电池内部不发生析锂，整个充电过程安全高效。
图8示出了按照本申请的充电方法，在-20℃下对正极极片包括磷酸铁锂的电芯进行10次充电放电循环后的电芯的拆解视图。如图7所示，负极极板的界面良好，无析锂发生。
为了对比本申请的充电方法和相关技术中的阶段充电方法的低温充电性能，申请人分别使用相关技术中的阶段充电方法和本申请的充电方法在-10℃下对正极极片包括磷酸铁锂的电芯进行充电实验。
<对比例1>
在相关技术中的阶段充电方法中，通过多个阶段对电化学装置充电，多个阶段所使用的充电电流逐渐降低，多个阶段的截止电压逐渐升高。相关技术中的阶段充电方法中的充电阶段的数量为8个，第1恒流充电阶段至第8恒流充电阶段的截止电压分别为V11、V21、…V81，V81＞V71＞…>V21＞V11。本申请的充电方法中，第二充电阶段包括5个子 阶段。
图9A示出了两种充电方法的电池电压对比，图9B示出了两种充电方法的充电时间对比。图9A示出了曲线1和曲线2，曲线1是使用本申请的充电方法对电化学装置充电过程中电池电压的曲线，曲线2是使用相关技术中的阶段充电方法对电化学装置充电过程中电池电压的曲线。如图9A所示，使用本申请的充电方法，在第二充电阶段将电芯SOC充至80％左右。图9B示出了曲线3和曲线4，曲线3是使用本申请的充电方法对电化学装置充电的电芯SOC和时间的关系曲线，曲线4是使用相关技术的阶段充电方法对电化学装置充电的电芯SOC和时间的关系曲线。如图9B所示，将电芯的SOC从0-0.5％充电到80％，本申请的充电方法比相关技术的阶段充电方法快2个多小时。这是因为在相关技术中的阶段充电方法中第一个充电阶段使用恒定的大电流对电芯充电，会导致电芯内部极化较大，电芯实际的充电电压较小(远小于第一个充电阶段的截止电压)，导致后续的充电阶段的时长较长，最终使得总的充电时间较长。因此，本申请的充电方法具有更高的充电效率。
<对比例2>
在相关技术中的阶段充电方法中，通过多个阶段对电化学装置充电，多个阶段所使用的充电电流逐渐降低。多阶段充电方法中的充电阶段的数量为8个，第1个恒流充电阶段的截止电压为V11，第2恒流充电阶段至第6恒流充电阶段使用相同的截止电压为V21，第7充电阶段使用截止电压V31,第8充电阶段使用截止电压V41，V41＞V31＞V21＞V11。对比实验中使用的本申请的充电方法，第二充电阶段包括5个子阶段。
图10A示出了两种充电方法的电池电压对比，图10B示出了两种充电方法的正极极片对锂电位对比。图10A示出了曲线1和曲线2，曲线1是使用本申请的充电方法对电化学装置充电过程中电池电压的曲线，曲线2是使用相关技术中的阶段充电方法对电化学装置充电过程中电池电压的曲线。如图10A所示，使用本申请的充电方法，在第二充电阶段将电芯SOC充至略大于60％。如图10A所示，本申请的充电方法中的第一充电阶段的截止电压比相关技术中的阶段充电方法的第一个阶段的截止电压V11低0.07V。图9B示出了曲线3和曲线4，曲线3是使用本申请的充电方法对电化学装置充电的电芯SOC和正极极片对锂电位的关系曲线，曲线4是使用相关技术的阶段充电方法对电化学装置充电的电芯SOC和正极极片对锂电位的关系曲线。如图10B所示，使用相关技术的阶段充电方法对电化学装置充电，当电芯SOC在60％至90％时，发生了析锂；使用本申请的充电方法，这段充电过程内没有发生析锂。因此，本申请的充电方法具有更高可靠性。
通过上述两个对比例可以看出，当前温度小于参考温度时，本申请的充电方法不仅能够提高充电效率，还能够避免发生析锂。
本申请还提供一种非暂态计算机存储介质，该非暂态计算机存储介质有计算机指令，当计算机指令在电化学装置10的控制器200上运行时，使得电化学装置10执行上述充电方法。非暂态计算机存储介质包括，但不限于，随机存取存储器(Random Access Memory，RAM)、只读存储器(Read-Only Memory，ROM)、电可擦可编程只读存储器(Electrically  Erasable Programmable Read Only Memory，EEPROM)、闪存、只读光盘(Compact Disc Read-Only Memory，CD-ROM)、数字多功能盘(Digital VideoDisc，DVD)或其他光盘存储、磁盒、磁带、磁盘存储或其他磁存储装置。
本申请还提供一种电子装置，电子装置包括前述任一实施方案中的电化学装置。电化学装置用于为电子装置供电。本申请提供的电化学装置能够在低温环境快速充电，保障了电子装置的续航能力。本申请的电子装置包括但不限于：笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池、锂离子电容器。注意的是，本申请的电化学装置除了适用于上述列举的电子装置外，还适用于储能电站、海运运载工具、空运运载工具。空运运载装置包含在大气层内的空运运载装置和大气层外的空运运载装置。
根据本申请实施例提供的电化学装置及其充电方法、计算机存储介质以及电子装置，按照当前温度确定充电方式，当温度小于参考温度时，在第一充电阶段使用较大充电电流对电化学装置进行恒流充电，在第二充电阶段使用多个子阶段恒流充电方式对电化学装置进行充电，第二充电阶段的多个子充电阶段的充电电流递减，并且多个子阶段具有相同的截止电压(与第一充电阶段的截止电压相同)，在第三充电阶段和第四充电阶段使用更小的充电电流对电化学装置进行恒流充电，并增大截止电压。通过设置第一充电阶段和第二充电阶段的多个子阶段具有相同的截止电压，缩短了第三和第四充电阶段的充电时间，并且能够更有效的控制正极极片的电位，避免析锂，并且有效降低电池充电过程的安全风险，适合低温下的锂电池充电。
以上实施方式仅用于说明本申请实施例，而并非对本申请实施例的限制，有关技术领域的普通技术人员，在不脱离本申请实施例的精神和范围的情况下，还可以做出各种变化和变型，因此所有等同的技术方案也属于本申请实施例的范畴，本申请实施例的专利保护范围应由权利要求限定。

Claims (10)

  1. 一种电化学装置，与控制器连接，响应于当前温度小于参考温度，所述控制器被配置为：
    在第一充电阶段，以第一充电电流对所述电化学装置充电至第一截止电压；
    在第二充电阶段，以多阶段恒流方式对所述电化学装置充电，其中，所述第二充电阶段包括依序的N个子阶段，N为正整数；在第(i)子阶段(i＝1、2、…、N-1)，以第(i)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，在第(i+1)子阶段，以第(i+1)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，所述第(i)子阶段充电电流小于所述第一充电电流，大于所述第(i+1)子阶段充电电流；
    在第三充电阶段，以第二充电电流对所述电化学装置充电至第二截止电压，所述第二充电电流小于所述第N子阶段充电电流；以及
    在第四充电阶段，以第三充电电流对所述电化学装置充电至第三截止电压，所述第三充电电流小于所述第二充电电流，
    其中，所述第三截止电压大于所述第二截止电压，所述第二截止电压大于所述第一截止电压。
  2. 根据权利要求1所述的电化学装置，其中，响应于当前温度大于所述参考温度，所述控制器还被配置为使所述充电模块以多个恒流充电阶段对所述电化学装置充电，所述多个恒流充电阶段的充电电流逐渐减小，所述多个恒流充电阶段的截止电压逐渐增大。
  3. 根据权利要求1所述的电化学装置，其中，所述参考温度为10℃至25℃。
  4. 根据权利要求1所述的电化学装置，其中，所述当前温度越低，所述第一截止电压和第一充电电流越小。
  5. 根据权利要求1所述的电化学装置，其中，所述电化学装置还包括存储器，所述存储器被配置为存储所述第一截止电压、第二截止电压、第三截止电压、第一充电电流、第二充电电流、第三充电电流以及所述第二充电阶段的N个子阶段的子阶段充电电流。
  6. 根据权利要求1所述的电化学装置，其中，所述电化学装置包括正极极片，所述正极极片包括磷酸铁锂。
  7. 一种电化学装置的充电方法，包括：
    判断当前温度是否小于参考温度；以及
    响应于当前温度小于所述参考温度，通过以下方式对所述电化学装置充电：
    在第一充电阶段，以第一充电电流对所述电化学装置充电至第一截止电压；
    在第二充电阶段，以多阶段恒流方式对所述电化学装置充电，其中，所述第二充电阶段包括依序的N个子阶段，N为正整数；在第(i)子阶段(i＝1、2、…、N-1)，以第(i)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，在第(i+1)子阶段，以第(i+1)子阶段充电电流对所述电化学装置进行恒流充电至所述第一截止电压，所述第(i)子阶段充电电流小于所述第一充电电流，大于所述第(i+1)子阶段充 电电流；
    在第三充电阶段，以第二充电电流对所述电化学装置充电至第二截止电压，所述第二充电电流小于所述第N子阶段充电电流；以及
    在第四充电阶段，以第三充电电流对所述电化学装置充电至第三截止电压，所述第三充电电流小于所述第二充电电流，
    其中，所述第三截止电压大于所述第二截止电压，所述第二截止电压大于所述第一截止电压。
  8. 根据权利要求7所述的充电方法，其中，所述充电方法还包括：响应于当前温度大于所述参考温度，通过多个恒流充电阶段对所述电化学装置充电，其中，所述多个恒流充电阶段的充电电流逐渐减小，所述多个恒流充电阶段的截止电压逐渐增大。
  9. 根据权利要求7所述的充电方法，其中，所述参考温度为10℃至25℃中的温度值。
  10. 一种电子装置，包括如权利要求1至6任一项所述的电化学装置。
PCT/CN2022/084536 2022-03-31 2022-03-31 电化学装置及其充电方法、电子装置 WO2023184390A1 (zh)

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Publication number Priority date Publication date Assignee Title
JP2011124166A (ja) * 2009-12-14 2011-06-23 Panasonic Corp リチウムイオン二次電池の充電方法
CN110098646A (zh) * 2018-01-31 2019-08-06 宁德新能源科技有限公司 充电方法、充电装置、终端及可读存储介质
CN110741503A (zh) * 2018-12-21 2020-01-31 Oppo广东移动通信有限公司 一种充电控制方法、装置及计算机存储介质
CN113782852A (zh) * 2021-08-27 2021-12-10 蜂巢能源科技有限公司 一种锂离子电池及其充放电方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011124166A (ja) * 2009-12-14 2011-06-23 Panasonic Corp リチウムイオン二次電池の充電方法
CN110098646A (zh) * 2018-01-31 2019-08-06 宁德新能源科技有限公司 充电方法、充电装置、终端及可读存储介质
CN110741503A (zh) * 2018-12-21 2020-01-31 Oppo广东移动通信有限公司 一种充电控制方法、装置及计算机存储介质
CN113782852A (zh) * 2021-08-27 2021-12-10 蜂巢能源科技有限公司 一种锂离子电池及其充放电方法

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