WO2023184336A1 - 电化学装置及其控制方法、电子设备和存储介质 - Google Patents

电化学装置及其控制方法、电子设备和存储介质 Download PDF

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WO2023184336A1
WO2023184336A1 PCT/CN2022/084405 CN2022084405W WO2023184336A1 WO 2023184336 A1 WO2023184336 A1 WO 2023184336A1 CN 2022084405 W CN2022084405 W CN 2022084405W WO 2023184336 A1 WO2023184336 A1 WO 2023184336A1
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electrochemical device
voltage
active material
cut
discharge
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PCT/CN2022/084405
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English (en)
French (fr)
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邹邦坤
屈长明
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宁德新能源科技有限公司
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Priority to PCT/CN2022/084405 priority Critical patent/WO2023184336A1/zh
Priority to CN202280007255.3A priority patent/CN116491006A/zh
Publication of WO2023184336A1 publication Critical patent/WO2023184336A1/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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the embodiments of the present application relate to the field of electrochemistry technology, and in particular, to an electrochemical device and its control method, electronic equipment and storage medium.
  • embodiments of the present application provide an electrochemical device and its control method, electronic equipment and storage medium, which can increase the volume energy density of the electrochemical device and enable the electrochemical device to have a longer service life.
  • an electrochemical device includes a first active material and a second active material, and the gram capacity of the first active material is less than the a second active material, the discharge operating voltage range of the first active material includes a first voltage range that is not greater than the upper limit of the discharge operating voltage of the second active material, and the electrochemical device discharges the
  • the electrochemical device operates at a cut-off voltage and a first charge cut-off voltage, and the electrochemical device operates at a second discharge cut-off voltage and a second charge cut-off voltage during a second time period, and the first discharge cut-off voltage and the second discharge cut-off voltage both Within the first voltage range; wherein the first discharge cut-off voltage is smaller than the second discharge cut-off voltage, and/or the first charging cut-off voltage is greater than the second charging cut-off voltage.
  • the electrochemical device operates at a first discharge cut-off voltage and a first charging cut-off voltage in a first time period, and the electrochemical device operates at a second discharge cut-off voltage and a second charging cut-off voltage in a second time period, and the first discharge cut-off voltage and The second discharge cut-off voltages are both within the first voltage range, and when the discharge cut-off voltage is within the first voltage range, more first active materials and more second active materials in the negative active material participate in the discharge.
  • the discharge cut-off voltage and the charge cut-off voltage of the device are such that the first discharge cut-off voltage is less than the second discharge cut-off voltage, and/or the first charge cut-off voltage is greater than the second charge cut-off voltage, by adjusting the capacity contributed by the second active material, so that The capacity contributed by the second active material corresponds to the health status of the electrochemical device and extends the service life of the electrochemical device. Therefore, the electrochemical device can have a longer service life on the premise of increasing the volumetric energy density of the electrochemical device.
  • the discharge operating voltage range of the first active material includes a second voltage range that is greater than the upper limit of the discharge operating voltage of the second active material, and the electrochemical device operates in a third time period with The third discharge cut-off voltage and the third charge cut-off voltage operate; wherein the third discharge cut-off voltage is located in the second voltage range, and/or the second charge cut-off voltage is greater than the third charge cut-off voltage.
  • the discharge cut-off voltage and the charge cut-off voltage of the chemical device are such that the third discharge cut-off voltage is in the second voltage range, and/or the second charge cut-off voltage is greater than the third charge cut-off voltage, so that the second active material does not participate in the electrochemical device.
  • the discharge process of the electrochemical device, or only a small amount of the second active material participates in the discharge process of the electrochemical device, so that after a large expansion of the second active material occurs, the second active material does not participate in the discharge process of the electrochemical device, thereby Suppress further expansion of the electrochemical device and extend the service life of the electrochemical device.
  • the electrochemical device performs at least one of the following operations during the fourth time period: (i) stopping charging and discharging; (ii) issuing an instruction to stop charging and discharging the electrochemical device. Information on charging and discharging operations.
  • the battery life and safety performance of the electrochemical device will decrease, affecting the user experience. Since the second active material will expand during the cycle, as the number of cycles of the electrochemical device increases, the volume of the electrochemical device will expand significantly, and the expansion of the electrochemical device will increase the risk of damage to the electronic equipment.
  • the electrochemical device is stopped charging and discharging, or a signal is issued to instruct the electrochemical device to stop charging and discharging operations. Information to prompt the user to replace the electrochemical device can improve the user experience and improve the safety of the electrochemical device use process.
  • the first time period, the second time period, the third time period and the fourth time period are in chronological order in the life cycle of the electrochemical device. arrangement.
  • the first time period, the second time period, the third time period and the fourth time period are arranged in chronological order in the life cycle of the electrochemical device.
  • the discharge cut-off voltage of the electrochemical device gradually increases in the chronological order of each time period.
  • the charging cut-off voltage of the electrochemical device is gradually reduced in the chronological order of each time period.
  • the advantage of the high gram capacity of the second active material is fully utilized to increase the volumetric energy density of the electrochemical device.
  • the capacity contributed by the second active material is reduced, the expansion rate of the electrochemical device is reduced, the service life of the electrochemical device is extended, and finally the charging and discharging operations of the electrochemical device are stopped or prompted to stop charging and discharging operations of the electrochemical device, thereby improving Users’ experience in using electrochemical devices and ensuring the safety of electronic equipment where the electrochemical devices are located.
  • the second active material includes silicon, the first voltage range is not greater than 3.5V, and the second voltage range is greater than 3.5V.
  • the second active material includes silicon
  • the first active material mainly participates in the discharge process of the electrochemical device, and no or only a small amount of the second active material participates.
  • both the first active material and the second active material will participate in the discharge process of the electrochemical device in greater amounts.
  • the first voltage range and the second voltage range use 3.5V as the dividing point.
  • the high gram capacity performance of the second active material can be fully utilized to increase the volumetric energy density of the electrochemical device.
  • the energy density can be reduced.
  • the expansion speed of the electrochemical device extends the service life of the electrochemical device.
  • the State of Health (SOH) parameter of the electrochemical device is located in different value ranges.
  • the SOH parameters of the electrochemical device are in different value ranges, that is, the first time period, the second time period, the third time period and the fourth time period can be determined according to the parameters of the electrochemical device. SOH parameters are determined.
  • determining the operating time periods of the electrochemical device based on the SOH parameters is to determine the operating time periods of the electrochemical device based on the health status of the electrochemical device, so that the electrochemical device can operate in Operating at different discharge cut-off voltages and/or charge cut-off voltages in different time periods ensures that the electrochemical device has a long service life while fully utilizing the high gram capacity performance of the second active material and improving the volumetric capacity density of the electrochemical device. .
  • the SOH parameters include at least one of the following: (i) the internal resistance of the electrochemical device; (ii) the reversible capacity of the electrochemical device; (iii) the The thickness of the electrochemical device; (iii) The pressure or pressure between the electrochemical device and the housing used to house the electrochemical device.
  • the internal resistance, reversible capacity, thickness, and pressure or pressure between the electrochemical device and the shell can all reflect the health status of the electrochemical device.
  • the internal resistance, reversible capacity of the electrochemical device , thickness, pressure between the shell and the shell, or one or more of them are used as SOH parameters, so that the SOH parameters can accurately reflect the health status of the electrochemical device, and then determine different time periods based on the SOH parameters.
  • the SOH parameter is the pressure between the electrochemical device and the housing; when the pressure between the electrochemical device and the housing is less than a first threshold, The electrochemical device operates during the first time period; when the pressure between the electrochemical device and the housing is greater than or equal to the first threshold and less than the second threshold, the electrochemical device The second period of time runs; when the pressure between the electrochemical device and the housing is greater than or equal to the second threshold and less than a third threshold, the electrochemical device operates in the third period of time. Run; when the pressure between the electrochemical device and the housing is greater than or equal to the third threshold, the electrochemical device runs in the fourth time period.
  • the pressure between the electrochemical device and the shell continues to increase, so the life cycle of the electrochemical device can be divided into four time periods through the first threshold, the second threshold, and the third threshold that increase in sequence.
  • the electrochemical device operates at different discharge cut-off voltages and/or charging cut-off voltages during the three time periods.
  • the expansion rate of the electrochemical device is slowed down and the service life of the electrochemical device is extended. Stop charging and discharging the electrochemical device in the last time period or prompting to stop charging and discharging the electrochemical device, thereby improving the user's experience of using the electrochemical device.
  • the first threshold is greater than or equal to 0.03MPa
  • the second threshold is less than 0.5MPa
  • the third threshold is greater than or equal to 0.5MPa
  • the second threshold is greater than the first threshold
  • the first threshold is set to be greater than or equal to 0.03MPa
  • the second threshold is less than 0.5MPa
  • the third threshold is greater than or equal to 0.5MPa.
  • the life cycle of the electrochemical device is divided into four by the first threshold, the second threshold and the third threshold. time period, the electrochemical device operates at different discharge cut-off voltages and/or charging cut-off voltages in the first three time periods. While making full use of the energy density of the electrochemical device, it slows down the deterioration of the cycle state of the electrochemical device and prolongs the battery life. The service life of chemical plants. Stopping the charging and discharging operations of the electrochemical device in the last period of time, or prompting the user to perform charging and discharging operations on the electrochemical device, can avoid crushing damage to the casing of the electrochemical device due to excessive irreversible expansion.
  • the mass proportion of silicon in the negative active material of the electrochemical device is in the range of (0%, 60%).
  • the volumetric energy density of the electrochemical device increases, but the cycle life of the electrochemical device decreases, making the mass proportion of silicon in the negative active material less than or equal to 60%, which can increase the volume energy density of the electrochemical device without excessively attenuating the cycle life of the electrochemical device, and then control the electrochemical device to use different discharge cut-off voltages and/or charge cut-off voltages in different time periods. Operation can ensure that the electrochemical device has a long cycle life on the premise of increasing the volume energy density of the electrochemical device.
  • the mass proportion of silicon in the negative active material of the electrochemical device is within the range of [10%, 20%].
  • the volumetric energy density of the electrochemical device can be improved. Due to the mass of silicon The proportion is less than or equal to 20% and will not have a significant impact on the cycle performance of the electrochemical device.
  • the electrochemical device can be fully utilized. While improving the energy density of the device, it ensures that the electrochemical device has a long cycle life.
  • an electrochemical device control method for controlling the charging and discharging process of the electrochemical device.
  • the negative active material of the electrochemical device includes a first active material and a second Active material, the gram capacity of the first active material is smaller than the second active material, and the discharge operating voltage range of the first active material includes a first voltage range that is not greater than the upper limit of the discharge operating voltage of the second active material.
  • the electrochemical device control method includes: controlling the electrochemical device to operate at a first discharge cut-off voltage and a first charge cut-off voltage in a first period of time, the first discharge cut-off voltage being within the first voltage range ; Controlling the electrochemical device to operate at a second discharge cut-off voltage and a second charge cut-off voltage in a second time period, the second discharge cut-off voltage being within the first voltage range; wherein, the first discharge cut-off voltage The voltage is less than the second discharge cut-off voltage, and/or the first charge cut-off voltage is greater than the second charge cut-off voltage.
  • the electrochemical device is controlled to operate at a first discharge cut-off voltage and a first charging cut-off voltage during a first time period, and the electrochemical device is controlled to operate at a second discharge cut-off voltage and a second charging cut-off voltage during a second time period.
  • the discharge cut-off voltage and the second discharge cut-off voltage are both within the first voltage range, and when the discharge cut-off voltage is within the first voltage range, more first active materials and more second active materials in the negative active material participate in discharge,
  • the first discharge cut-off voltage is less than the second discharge cut-off voltage, and/or the first charge cut-off voltage is greater than the second charge cut-off voltage, thereby adjusting the contribution of the second active material capacity, so that the capacity contributed by the second active material corresponds to the health status of the electrochemical device, prolonging the service life of the electrochemical device, and therefore enabling the electrochemical device to have a longer life on the premise of increasing the volumetric energy density of the electrochemical device. service life.
  • the discharge operating voltage range of the first active material includes a second voltage range greater than the upper limit of the discharge operating voltage of the second active material
  • the electrochemical device control method further includes: controlling The electrochemical device operates at a third discharge cut-off voltage and a third charge cut-off voltage during a third time period; wherein the third discharge cut-off voltage is located in the second voltage range, and/or the second charge The cut-off voltage is greater than the third charging cut-off voltage.
  • the electrochemical device control method further includes: controlling the electrochemical device to perform at least one of the following operations during the fourth time period: (i) stopping charging and discharging; (ii) issuing Information used to instruct to stop charging and discharging operations on the electrochemical device.
  • the first time period, the second time period, the third time period and the fourth time period are in chronological order in the life cycle of the electrochemical device. arrangement.
  • the electrochemical device control method further includes: determining the time period in which the electrochemical device is located based on the value range of the SOH parameter of the electrochemical device.
  • the SOH parameters include at least one of the following: (i) the internal resistance of the electrochemical device; (ii) the reversible capacity of the electrochemical device; (iii) the The thickness of the electrochemical device; (iii) The pressure or pressure between the electrochemical device and the housing used to house the electrochemical device.
  • the mass proportion of silicon in the negative active material of the electrochemical device is in the range of (0%, 60%).
  • the mass proportion of silicon in the negative active material of the electrochemical device is within the range of [10%, 20%].
  • an electrochemical device management system is provided.
  • the electrochemical device management system is connected to the electrochemical device.
  • the electrochemical device management system is used to perform the above second aspect or the second aspect. Any possible implementation of the aspect provides an electrochemical device control method.
  • an electronic device including the electrochemical device provided by the above first aspect or any possible implementation of the first aspect, or including the electrochemical device management provided by the above third aspect. system.
  • a computer-readable storage medium is provided.
  • a computer program is stored on the computer-readable storage medium.
  • the computer program is executed by a processor, the above-mentioned second aspect or the third aspect is implemented. Any possible implementation of the two aspects provides an electrochemical device control method.
  • the electrochemical device operates at the first discharge cut-off voltage and the first charging cut-off voltage in the first time period, and the electrochemical device operates at the second discharge cut-off voltage and the second charging cut-off voltage in the second time period
  • the first discharge cut-off voltage and the second discharge cut-off voltage are both within the first voltage range, and when the discharge cut-off voltage is within the first voltage range, there are more first active materials and more second active materials participating in the negative active material.
  • Discharge by adjusting the discharge cut-off voltage and the charge cut-off voltage of the electrochemical device, so that the first discharge cut-off voltage is less than the second discharge cut-off voltage, and/or the first charge cut-off voltage is greater than the second charge cut-off voltage, by adjusting the second activity
  • the capacity contributed by the material makes the capacity contributed by the second active material correspond to the health status of the electrochemical device, extending the service life of the electrochemical device. Therefore, it is possible to increase the volume energy density of the electrochemical device and make the electrochemical device have Longer service life.
  • Figure 1 is a schematic diagram of an electrochemical device detecting shell pressure according to an embodiment of the present application
  • Figure 2 is a schematic diagram of the expansion curve of the electrochemical device and the change of the pressure on the housing with the number of cycles according to one embodiment of the present application;
  • Figure 3 is a flow chart of an electrochemical device control method according to an embodiment of the present application.
  • electrochemical device and its control method, electronic equipment and storage medium in the embodiment of the present application are first described in detail, and then some related experiments on the electrochemical device and the control method of the electrochemical device in the embodiment of the present application are given. Examples and Comparative Examples are used to illustrate the significant advantages of the electrochemical device and its control method, electronic equipment and storage medium in the embodiments of the present application over the existing technology.
  • the present application is explained by taking a lithium ion battery as an example of an electrochemical device, but the electrochemical device of the present application is not limited to lithium ion batteries.
  • Electrochemical devices provide electrical energy for electronic products such as laptops, mobile phones, tablets, power banks and drones. Lithium-ion batteries, sodium-ion batteries, etc. all use graphite anode systems. As the requirements for the weight, volume and endurance of electronic equipment cannot be improved, the volumetric energy density of electrochemical devices needs to be improved. Materials with larger gram capacities, such as silicon and phosphorus, have higher reversible capacities. Therefore, applying silicon, phosphorus and other materials to the negative electrode materials of electrochemical devices can continue to increase the volume energy density of electrochemical devices, but the larger gram capacity The negative electrode material will expand greatly during the cycle, affecting the service life of the electrochemical device. Therefore, there is a need for a technical solution that can increase the volumetric energy density of an electrochemical device and ensure a long service life of the electrochemical device.
  • Embodiments of the present application provide an electrochemical device.
  • the negative active material of the electrochemical device includes a first active material and a second active material.
  • the gram capacity of the first active material is smaller than that of the second active material.
  • the discharge of the first active material The operating voltage range includes a first voltage range that is no greater than an upper limit of the discharge operating voltage of the second active material.
  • the electrochemical device operates at a first discharge cut-off voltage and a first charging cut-off voltage in a first time period, and the electrochemical device operates at a second discharge cut-off voltage and a second charging cut-off voltage in a second time period, and the first discharge cut-off voltage and The second discharge cut-off voltages are all within the first voltage range.
  • the first discharge cut-off voltage is smaller than the second cut-off voltage, and/or the first charging cut-off voltage is greater than the second charging cut-off voltage.
  • Gram capacity refers to the ratio of the electric capacity that can be released by the active material inside the battery to the mass of the active material.
  • the unit of gram capacity is milliamp-hour per gram (mA ⁇ h/g).
  • the gram capacity of the first active material is less than that of the second active material.
  • the amount of electricity that the first active material can release is less than that of the second active material. The amount of electricity released.
  • the first active material can be graphite, mesocarbon microbeads (MCMB) or Li 4 Ti 5 O 12 , etc.
  • the second active material can be SiO x (0 ⁇ x ⁇ 2), micron silicon, silicon nanowires , SiC, transition metal oxides (such as MnO, SnO 2 , CoO, etc.) or phosphorus, etc.
  • the above-mentioned first active materials and second active materials may be freely combined, and the negative active material of the electrochemical device may include a plurality of first active materials and/or a plurality of second active materials.
  • the second active material has a discharge operating voltage range, and within the discharge operating voltage range, both the first active material and the second active material contribute a larger capacity.
  • the first active material mainly contributes capacity, and a small amount of the second active material also contributes capacity.
  • the capacity contributed by the first active material is greater than 80%.
  • the second active material mainly contributes capacity, and a small amount of the first active material also contributes capacity.
  • the capacity contributed by the second active material is greater than 80%.
  • the anti-electricity working voltage range of the first active material includes a first voltage range that is not greater than the upper limit of the discharge working voltage of the second active material.
  • the upper limit of the discharge working voltage of the second active material refers to the upper limit of the discharge working voltage range of the second active material.
  • the discharge operating voltage range of the second active material is [2.3V, 3.5V]
  • the upper limit of the discharge operating voltage of the second active material is 3.5V
  • the first voltage range is [2.3V, 3.5V].
  • the first voltage range is not greater than the upper limit of the discharge operating voltage of the second active material, that is, any voltage value within the first voltage range is less than or equal to the upper limit of the discharge operating voltage of the second active material.
  • both the first active material and the second active material contribute a larger capacity, that is, when the discharge voltage of the electrochemical device is within the first voltage range, more first active materials and more The second active material participates in the discharge process of the electrochemical device, and the first voltage range may be the same as the discharge operating voltage range of the second active material.
  • the first time period and the second time period may be the first cycle stage and the second cycle stage in the entire life cycle of the electrochemical device, that is, the first time period and the second time period correspond to different charge and discharge cycles of the electrochemical device,
  • the first time period is from the 300th charge and discharge cycle to the 450th charge and discharge cycle of the electrochemical device
  • the second time period is from the 451st charge and discharge cycle to the 600th charge and discharge cycle of the electrochemical device.
  • the first time period and the second time period may include one or more charge and discharge cycles of the electrochemical device, and the number of charge and discharge cycles included in the first time period and the second time period may be the same or different.
  • the electrochemical device operates at a first discharge cut-off voltage and a first charging cut-off voltage in a first time period, and the electrochemical device operates at a second discharge cut-off voltage and a second charging cut-off voltage in a second time period.
  • the first discharge cut-off voltage and the second discharge cut-off voltage are both within the first voltage range, and when the discharge cut-off voltage is within the first voltage range, there are more first active materials and more second active materials in the negative active material.
  • the capacity contributed by the active material makes the capacity contributed by the second active material correspond to the health status of the electrochemical device, extending the service life of the electrochemical device. Therefore, the electrochemical device can be made more efficient while increasing the volume energy density of the electrochemical device. Has a long service life.
  • the discharge operating voltage range of the first active material includes a second voltage range that is greater than the upper limit of the discharge operating voltage of the second active material, and the electrochemical device operates at a third discharge cut-off voltage and The third charging cut-off voltage operates.
  • the third discharge cut-off voltage is within the second voltage range, and/or the second charging cut-off voltage is greater than the third charging cut-off voltage.
  • the discharge operating voltage range of the first active material not only includes the first voltage range, but also includes a second voltage range that is greater than the upper limit of the discharge operating voltage of the second active material.
  • the discharge operating voltage range of the second active material is [2.3V, 3.5 V]
  • the upper limit of the discharge operating voltage of the second active material is 3.5V
  • the second voltage range is (3.5V, 4.5V].
  • the second voltage range is greater than the upper limit of the discharge operating voltage of the second active material, that is, within the second voltage range Any voltage value is greater than the upper limit of the discharge operating voltage of the second active material. Since the second voltage range is greater than the upper limit of the discharge operating voltage of the second active material, within the second voltage range, the capacity is mainly contributed by the first active material.
  • the second active material does not contribute capacity or only contributes a small amount of capacity.
  • the capacity contributed by the first active material is greater than 80%, that is, when the discharge voltage of the electrochemical device is within the second voltage range, more of the first active material participates in the electrochemistry. The discharge process of the device, while less or no second active material participates in the discharge process of the electrochemical device.
  • the third discharge cut-off voltage is located in the second voltage range
  • the first voltage range is not greater than the upper limit of the discharge operating voltage of the second active material
  • the second voltage The range is greater than the upper limit of the discharge operating voltage of the second active material, so the third discharge cut-off voltage is greater than the first discharge cut-off voltage and the second discharge cut-off voltage.
  • the electrochemical device operates at a third discharge cut-off voltage and a third charge cut-off voltage during the third time period, the third discharge cut-off voltage is within the second voltage range, and the discharge cut-off voltage is within the second voltage range.
  • the third discharge cut-off voltage is in the second voltage range, and/or the second charging cut-off voltage is greater than the third charging cut-off voltage, so that the second active material does not participate in the discharge process of the electrochemical device, or only a small amount of the second active material participates.
  • the discharge process of the electrochemical device so that after the second active material undergoes a large expansion, the second active material does not participate in the discharge process of the electrochemical device, thereby inhibiting further expansion of the electrochemical device and extending the service life of the electrochemical device .
  • the electrochemical device may perform at least one of the following operations in the fourth time period:
  • the battery life and safety performance of the electrochemical device will decrease, affecting the user experience. Since the second active material will expand during the cycle, as the number of cycles of the electrochemical device increases, the volume of the electrochemical device will expand significantly, and the expansion of the electrochemical device will increase the risk of damage to the electronic equipment.
  • the electrochemical device is stopped charging and discharging, or a signal is issued to instruct the electrochemical device to stop charging and discharging operations. Information to prompt the user to replace the electrochemical device can improve the user experience and improve the safety of the electrochemical device use process.
  • the first time period, the second time period, the third time period and the fourth time period are arranged in chronological order in the life cycle of the electrochemical device.
  • both the first active material and the second active material participate in the discharge process of the electrochemical device, taking full advantage of the high gram capacity advantage of the second active material.
  • the The second active material gradually expands.
  • the participation degree of the second active material in the discharge process can be reduced and the expansion speed of the electrochemical device can be reduced.
  • the first active material mainly participates in the discharge process of the electrochemical device.
  • the expansion of the second active material during the cycle is greater than that of the first active material, after the electrochemical device has experienced a larger volume expansion, Further increasing the discharge cut-off voltage of the electrochemical device can prevent the second active material from participating in the discharge process of the electrochemical device, thereby further reducing the expansion speed of the electrochemical device and extending the service life of the electrochemical device.
  • the expansion degree of the electrochemical device has affected the safety of the electronic equipment. Stopping the charging and discharging operations of the electrochemical device or prompting to stop charging and discharging the electrochemical device can improve the user experience and ensure the battery life. Safety of electronic equipment in which chemical devices are located.
  • lowering the charge cut-off voltage of the electrochemical device can also reduce the participation of the second active material in the cycle process of the electrochemical device, thereby reducing the expansion speed of the electrochemical device and prolonging the battery life.
  • the first time period, the second time period, the third time period and the fourth time period are arranged in chronological order in the life cycle of the electrochemical device, and the discharge cutoff voltage of the electrochemical device is arranged according to each time period.
  • the time sequence of each period gradually increases, and the charging cut-off voltage of the electrochemical device gradually decreases according to the time sequence of each time period.
  • the advantage of the high gram capacity of the second active material is fully utilized to increase the volume energy of the electrochemical device.
  • Density in the later stages of the electrochemical device cycle, reduces the capacity contributed by the second active material, reduces the expansion rate of the electrochemical device, extends the service life of the electrochemical device, and ultimately stops charging and discharging the electrochemical device or prompts to stop charging the electrochemical device.
  • the device performs charge and discharge operations to improve the user's experience of using the electrochemical device and ensure the safety of the electronic equipment where the electrochemical device is located.
  • the second active material includes silicon
  • the first voltage range is no more than 3.5V
  • the second voltage range is more than 3.5V.
  • the first active material when the second active material includes silicon, during the discharge process of the electrochemical device, when the discharge voltage is above 3.5V, the first active material mainly participates in the discharge process of the electrochemical device, without or only A small amount of the second active material participates in the discharge process of the electrochemical device, and when the discharge voltage is below 3.5V, both the first active material and the second active material participate in the discharge process of the electrochemical device in larger amounts.
  • the first voltage range and the second voltage range use 3.5V as the dividing point.
  • the high gram capacity performance of the second active material can be fully utilized to increase the volumetric energy density of the electrochemical device.
  • the energy density In the second period of time, the energy density can be reduced.
  • the expansion speed of the electrochemical device extends the service life of the electrochemical device.
  • the state of health (SOH) parameters of the electrochemical device are in different value ranges.
  • the SOH parameters of the electrochemical device are located in different value ranges, that is, the first time period, the second time period, the third time period and the fourth time.
  • the segments can be determined based on the SOH parameters of the electrochemical device.
  • determining the operating time periods of the electrochemical device based on the SOH parameters is to determine the operating time periods of the electrochemical device based on the health status of the electrochemical device, so that the electrochemical device can operate in Operating at different discharge cut-off voltages and/or charge cut-off voltages in different time periods ensures that the electrochemical device has a long service life while fully utilizing the high gram capacity performance of the second active material and improving the volumetric capacity density of the electrochemical device. .
  • the SOH parameters of the electrochemical device may include at least one of the following:
  • the internal resistance, reversible capacity, thickness, and pressure or pressure between the electrochemical device and the shell can all reflect the health status of the electrochemical device.
  • One or more of the internal resistance, reversible capacity, thickness, and pressure between the device and the shell are used as SOH parameters, so that the SOH parameters can accurately reflect the health status of the electrochemical device, and then different parameters are determined based on the SOH parameters.
  • time period by adjusting the discharge cut-off voltage and charge cut-off voltage of the electrochemical device in different time periods, making full use of the high gram capacity performance of the second active material, and prolonging the electrochemical process on the premise of increasing the volumetric energy density of the electrochemical device. The service life of the device.
  • the thickness of the electrochemical device can be used as an SOH parameter that reflects the health status of the electrochemical device.
  • the electrochemical device is located in the casing of an electronic device, such as when the electrochemical device is located inside the casing of a mobile phone, the expansion of the electrochemical device will change the pressure and pressure between it and the casing, so the electrochemical device can be contained with the user.
  • the pressure or pressure between the shells of the electrochemical device serves as the SOH parameter that reflects the health status of the electrochemical device.
  • FIG. 1 is a schematic diagram of the case pressure detection by the electrochemical device according to an embodiment of the present application.
  • the electrochemical device 11 is disposed in the housing 12, and a pressure sensor 13 is disposed between the electrochemical device 11 and the lower side wall of the housing 12.
  • the volume of the electrochemical device 11 expands.
  • the pressure of the electrochemical device 11 on the housing 12 increases, so that the expansion degree of the electrochemical device 11 can be determined based on the pressure value detected by the pressure sensor 13 .
  • the electrochemical device management system obtains the pressure value detected by the pressure sensor 13 and divides it by the contact area between the pressure sensor 13 and the electrochemical device 11 , the pressure between the electrochemical device 11 and the housing 12 can be determined.
  • a first threshold, a second threshold and a third threshold are set for the pressure between the electrochemical device and the casing,
  • the first threshold is less than the second threshold
  • the second threshold is less than the third threshold.
  • the electrochemical device operates during the first time period.
  • the pressure between the electrochemical device and the housing is greater than or equal to the first threshold and less than the second threshold
  • the electrochemical device operates during the second time period.
  • the pressure between the electrochemical device and the housing is greater than or equal to the second threshold and less than the third threshold
  • the electrochemical device operates in the third time period.
  • the pressure between the electrochemical device and the housing is greater than or equal to the third pressure
  • the electrochemical device operates in the fourth time period.
  • Figure 2 is a curve of the expansion of the electrochemical device and the change of the pressure on the shell with the number of cycles according to an embodiment of the present application.
  • curve 201 is the variation curve of the expansion percentage of the electrochemical device with the number of cycles
  • curve 202 is the variation curve of the pressure of the electrochemical device on the shell with the number of cycles. It can be seen from the curve 201 that as the number of cycles of the electrochemical device increases, the expansion percentage of the electrochemical device gradually increases, that is, the volume of the electrochemical device gradually increases, and the health condition of the electrochemical device continues to deteriorate. It can be seen from the curve 202 that as the number of cycles of the electrochemical device increases, the pressure of the electrochemical device on the housing gradually increases.
  • the expansion percentage of the electrochemical device is positively related to the pressure of the electrochemical device on the shell, and the expansion degree of the electrochemical device can reflect the health status. Therefore, the electrochemical device can be calculated according to the pressure of the electrochemical device on the shell.
  • the life cycle of the device is divided into multiple time periods.
  • the health status of the electrochemical device is different in different time periods.
  • the life cycle of the electrochemical device can be divided into four time periods through the sequentially increasing first threshold, second threshold and third threshold.
  • the electrochemical device operates with different discharge cut-off voltages and/or Or charge cut-off voltage operation, on the premise of increasing the volume capacity density of the electrochemical device, slowing down the expansion rate of the electrochemical device, extending the service life of the electrochemical device, and stopping charging and discharging operations or prompts for the electrochemical device in the last period of time Stop charging and discharging the electrochemical device to improve the user experience of the electrochemical device.
  • the first threshold is greater than or equal to 0.03MPa
  • the second threshold is less than 0.5MPa
  • the third threshold is greater than or equal to 0.5MPa.
  • the first threshold is set to be greater than or equal to 0.03MPa and less than 0.5MPa, so that the electrochemical device can operate at a lower discharge cutoff voltage and/or a higher charge cutoff voltage when the cycle state is good, and fully utilize the energy density of the electrochemical device.
  • the second threshold is set to be greater than the first threshold and less than 0.5MPa.
  • the third threshold value to be greater than or equal to 0.5MPa to ensure that the electrochemical device can charge and discharge when the cycle state is good, fully utilize the energy density of the electrochemical device, and stop the electrochemical device when the electrochemical device expands greatly.
  • 0.5MPa 0.5MPa
  • the first threshold is set to be greater than or equal to 0.03MPa
  • the second threshold is less than 0.5MPa
  • the third threshold is greater than or equal to 0.5MPa.
  • the electrochemical device is configured through the first threshold, the second threshold, and the third threshold.
  • the life cycle of the electrochemical device is divided into four time periods.
  • the electrochemical device operates with different discharge cut-off voltages and/or charging cut-off voltages in the first three time periods. While making full use of the energy density of the electrochemical device, it slows down the degradation of the electrochemical device. The deterioration of the cycle state extends the service life of the electrochemical device. Stopping the charging and discharging operations of the electrochemical device in the last period of time, or prompting the user to perform charging and discharging operations on the electrochemical device, can avoid crushing damage to the casing of the electrochemical device due to excessive irreversible expansion.
  • the mass proportion of silicon in the negative active material of the electrochemical device is in the range of (0%, 60%).
  • the mass proportion of silicon in the negative active material is 1%, 10 %, 20%, 30% or 60% etc.
  • the volumetric energy density of the electrochemical device increases, but the cycle life of the electrochemical device decreases, causing the silicon in the negative active material to
  • the mass proportion is less than or equal to 60%, which can improve the volume energy density of the electrochemical device without excessively attenuating the cycle life of the electrochemical device, and then control the electrochemical device to have different discharge cutoffs in different time periods. Voltage and/or charging cut-off voltage operation can ensure that the electrochemical device has a longer cycle life on the premise of increasing the volume energy density of the electrochemical device.
  • the mass proportion of silicon in the negative active material of the electrochemical device is in the range [10%, 20%].
  • the mass proportion of silicon in the negative active material is 1%, 10% Or 20% etc.
  • the volume of the electrochemical device can be increased. Energy density, since the mass proportion of silicon is less than or equal to 20%, will not have a significant impact on the cycle performance of the electrochemical device.
  • FIG. 3 is a flow chart of an electrochemical device control method according to an embodiment of the present application, which is used to control the charging and discharging process of the electrochemical device.
  • the negative active material of the electrochemical device includes a first active material and a second active material.
  • the gram capacity of one active material is smaller than that of the second active material, and the discharge operating voltage range of the first active material includes a first voltage range that is not greater than the upper limit of the discharge operating voltage of the second active material.
  • the electrochemical device control method includes the following steps:
  • Step 301 Control the electrochemical device to operate at a first discharge cut-off voltage and a first charge cut-off voltage during a first period of time.
  • the life cycle of the electrochemical device includes a first time period, and the electrochemical device is controlled to operate at a first discharge cut-off voltage and a first charge cut-off voltage in the first time period, wherein the first discharge cut-off voltage is within a first voltage range. .
  • Step 302 Control the electrochemical device to operate at the second discharge cut-off voltage and the second charge cut-off voltage during the second time period.
  • the life cycle of the electrochemical device includes a second time period different from the first time period, and the electrochemical device is controlled to operate at a second discharge cut-off voltage and a second charge cut-off voltage in the second time period, wherein the second discharge cut-off voltage The voltage is within the first voltage range, and the first discharge cut-off voltage is less than the second discharge cut-off voltage and/or the first charge cut-off voltage is greater than the second charge cut-off voltage.
  • the electrochemical device is controlled to operate at the first discharge cut-off voltage and the first charging cut-off voltage during the first time period, and the electrochemical device is controlled to operate at the second discharge cut-off voltage and the second charge cut-off voltage during the second time period.
  • the first discharge cut-off voltage and the second discharge cut-off voltage are both within the first voltage range, and when the discharge cut-off voltage is within the first voltage range, there are more first active materials and more of the negative active material.
  • the second active material participates in the discharge, by adjusting the discharge cut-off voltage and the charge cut-off voltage of the electrochemical device, so that the first discharge cut-off voltage is less than the second discharge cut-off voltage, and/or the first charge cut-off voltage is greater than the second charge cut-off voltage, Then, the capacity contributed by the second active material is adjusted so that the capacity contributed by the second active material corresponds to the health state of the electrochemical device, thereby extending the service life of the electrochemical device. Therefore, on the premise of increasing the volume energy density of the electrochemical device, The electrochemical device has a long service life.
  • the discharge operating voltage range of the first active material includes a second voltage range that is greater than the upper limit of the discharge operating voltage of the second active material.
  • the electrochemical device control method further includes:
  • the electrochemical device is controlled to operate at a third discharge cut-off voltage and a third charge cut-off voltage during a third time period.
  • the third discharge cut-off voltage is located in the second voltage range, and/or the second charging cut-off voltage is greater than the third charging cut-off voltage.
  • the electrochemical device control method further includes: controlling the electrochemical device to perform at least one of the following operations during the fourth time period:
  • the life cycle of the electrochemical device includes the above-mentioned first time period, second time period, third time period and fourth time period, the first time period, the second time period, the third time period and the fourth time period.
  • the three time periods and the fourth time period are arranged chronologically in the life cycle of the electrochemical device.
  • the electrochemical device control method further includes: determining the time period in which the electrochemical device is located based on the value range of the health status parameter of the electrochemical device.
  • the health state parameter includes at least one of the following: (i) internal resistance of the electrochemical device; (ii) reversible capacity of the electrochemical device; (iii) thickness of the electrochemical device; (iii) The pressure or pressure between the electrochemical device and the casing used to house the electrochemical device.
  • the mass proportion of silicon in the negative active material of the electrochemical device is in the range of (0%, 60%).
  • the mass proportion of silicon in the negative active material of the electrochemical device is within the range of [10%, 20%].
  • One embodiment of the present application provides an electrochemical device management system.
  • the electrochemical device management system is connected to the electrochemical device.
  • the electrochemical device management system is used to execute the electrochemical device control method in the foregoing embodiment.
  • One embodiment of the present application provides an electronic device, including the electrochemical device or the electrochemical device management system in the above embodiment.
  • Electronic devices can be mobile phones, drones, etc.
  • the negative active material of the electrochemical device in the electronic device includes a first active material and a second active material.
  • the first active material has a smaller gram capacity than the second active material.
  • the presence of the second active material can increase the volume energy of the electrochemical device. Density enables electronic devices to have stronger battery life. Controlling the electrochemical device in the electronic equipment to operate at different discharge cut-off voltages and/or charge cut-off voltages in different time periods can slow down the decay of the cycle life of the electrochemical device, thereby extending the service life of the electrochemical device and improving users' understanding of electronic devices. Device usage experience.
  • This application also provides a computer-readable storage medium, which stores a computer program.
  • the computer program is executed by a processor, the electrochemical device control method in any of the above embodiments is implemented.
  • a system or device equipped with a storage medium may be provided, on which the software program code that implements the functions of any of the above embodiments is stored, and the computer (or CPU or MPU) of the system or device ) reads and executes the program code stored in the storage medium.
  • the program code itself read from the storage medium can implement the functions of any one of the above embodiments, and therefore the program code and the storage medium storing the program code form part of this application.
  • Examples of storage media for providing program codes include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), Tapes, non-volatile memory cards and ROM.
  • the program code can be downloaded from the server computer via the communications network.
  • the program code read from the storage medium is written into the memory provided in the expansion board inserted into the computer or written into the memory provided in the expansion module connected to the computer, and then based on the program code
  • the instructions cause the CPU installed on the expansion board or expansion module to perform part or all of the actual operations, thereby realizing the functions of any of the above embodiments.
  • Embodiments of the present application also provide a computer program product.
  • the computer program product is stored on a computer-readable medium and includes computer-executable instructions. When executed, the computer-executable instructions cause at least one processor to perform any of the above.
  • a method for controlling an electrochemical device in an embodiment It should be understood that each solution in this embodiment has the corresponding technical effects in the above method embodiment, and will not be described again here.
  • Preparation of the positive electrode sheet Mix the positive active materials lithium cobalt oxide, conductive carbon black (SuperP), and polyvinylidene fluoride (PVDF) in a weight ratio of 97:1.4:1.6, and add N-methylpyrrolidone (NMP) as Solvent and stir evenly to form a positive electrode slurry (solid content: 72wt%).
  • the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil with a coating thickness of 80 ⁇ m, dried at 85°C, then cold pressed, cut into pieces, slit, and dried under vacuum conditions at 85°C for 4 hours. Get the positive electrode piece.
  • Preparation of the negative electrode sheet Dissolve artificial graphite, binder polyacrylic acid and sodium carboxymethylcellulose (CMC) in deionized water in a weight ratio of 97:1.5:1.5 to form a negative electrode slurry (solid content: 40wt%) .
  • CMC carboxymethylcellulose
  • the isolation film is 7 ⁇ m thick polyethylene (PE).
  • Preparation of lithium-ion battery Stack the positive electrode sheet, isolation film, and negative electrode sheet in order so that the isolation film is between the positive electrode and the negative electrode to play the role of isolation, and wind it to obtain the electrode assembly.
  • the electrode assembly is placed in the outer packaging aluminum plastic film, and after the moisture is removed at 80°C, the above-mentioned electrolyte is injected and packaged, and a lithium-ion battery is obtained through processes such as formation, degassing, and trimming.
  • Cycling conditions A single cycle condition remains unchanged, in which the discharge cut-off voltage is 3.0V and the charging cut-off voltage is 4.45V.
  • Electrochemical device cycle number test Use the cycle test instrument to conduct constant current and constant voltage charge and discharge tests on the battery cells according to the set charge and discharge cut-off voltage.
  • the charge and discharge cut-off voltages of a single battery are 4.45V and 3.0V respectively.
  • the cycle tester charges to 4.45V at 3C constant current and constant voltage at 25°C, and then discharges to 3.0V at 0.5C as one cycle. Repeatedly test as a single battery for different number of cycles.
  • testing of lithium-ion battery voltage, internal resistance, and cycle life is a technology well known to those skilled in the art, and will not be described here.
  • the testing method is not limited to the method described in this application, and other suitable tests can also be used. method.
  • Comparative Examples 2 to 7 The difference between Comparative Examples 2 to 7 and Comparative Example 1 is that part of the artificial graphite in the negative active material was replaced with the silicon-based material Si-C.
  • the mass proportion of Si element in the negative active material was 1%.
  • the mass proportion of Si element in the negative active material is 10%
  • the mass proportion of Si element in the negative active material is 20%
  • the mass proportion of Si element in the negative active material is 30% %
  • the mass proportion of Si element in the negative active material is 60%
  • Comparative Example 7 the mass proportion of Si element in the negative active material is 90%.
  • Table 1 below shows the energy density test results of Comparative Examples 1 to 7 and the test results of the number of cycles when the capacity decays to 80%.
  • Comparative Examples 8 to 13 The difference between Comparative Examples 8 to 13 and Comparative Example 1 is that part of the artificial graphite in the negative active material was replaced with the silicon-based material Si-C, so that the mass proportion of the Si element in the negative active material was 30%.
  • the discharge cut-off voltage is 2.3V
  • the discharge cut-off voltage of Comparative Example 9 is 2.5V
  • the discharge cut-off voltage of Comparative Example 10 is 2.8V
  • the discharge cut-off voltage of Comparative Example 11 is 3.2V
  • the discharge cut-off voltage of Comparative Example 12 is 3.4V.
  • the discharge cut-off voltage of Comparative Example 13 is 3.5V.
  • the charging cut-off voltage of Comparative Examples 8 to 13 remained the same as Comparative Example 5, which was 4.45V.
  • Table 2 below shows the energy density test results of Comparative Example 5 and Comparative Examples 8-13 and the test results of the number of cycles when the capacity decays to 80%.
  • Comparative Examples 14 to 17 The difference between Comparative Examples 14 to 17 and Comparative Example 1 is that part of the artificial graphite in the negative active material was replaced with the silicon-based material Si-C, so that the mass proportion of the Si element in the negative active material was 30%.
  • the charge cut-off voltage is 4.2V
  • the charge cut-off voltage of Comparative Example 15 is 4.3V
  • the charge cut-off voltage of Comparative Example 16 is 4.6V
  • the charge cut-off voltage of Comparative Example 17 is 4.9V.
  • the discharge cut-off voltage of Comparative Examples 14 to 17 remained the same as Comparative Example 5, which was 3.0V.
  • Table 3 shows the energy density test results of Comparative Example 5 and Comparative Examples 14-17 and the test results of the number of cycles when the capacity decays to 80%.
  • the difference between Experimental Examples 1 to 5 and Comparative Example 5 is that part of the artificial graphite in the negative active material was replaced with the silicon-based material Si-C, so that the mass proportion of Si element in the negative active material was 30%, and the charging cut-off voltage was maintained 4.45V, the initial discharge cut-off voltage (first discharge cut-off voltage) is 3.0V, after the pressure between the electrochemical device and the shell reaches the corresponding first threshold, the discharge cut-off voltage is increased by 0.2V, that is, the electrochemical device The discharge cut-off voltage is adjusted to the second discharge cut-off voltage (3.2V), where the first threshold corresponding to Experimental Example 1 is 0.03MPa, the first threshold corresponding to Experimental Example 2 is 0.05MPa, and the first threshold corresponding to Experimental Example 3 is 0.08MPa, the first threshold corresponding to Experimental Example 4 is 0.10MPa, and the first threshold corresponding to Experimental Example 5 is 0.15MPa.
  • Table 4 shows the test results of the number of cycles when the discharge cut-off voltage is increased and the number of cycles when the capacity decays to 80% in Comparative Example 5 and Experimental Examples 1-5.
  • the pressure between the electrochemical device and the shell is less than the first threshold, it means that the irreversible expansion of the electrochemical device is small, the cycle performance of the electrochemical device and the pressure on the shell are within a controllable range, and the initial discharge cut-off voltage can be Perform charge and discharge cycles.
  • the first threshold is set to a small value (such as 0.01MPa in Experimental Example 1), the discharge cut-off voltage of the electrochemical device will increase after 50 cycles, which is not conducive to fully utilizing the energy density of the electrochemical device. .
  • the electrochemical device will only increase the discharge cutoff voltage after 400 cycles, which will increase the cycle life of the electrochemical device and cause irreversible expansion. Improvements are relatively limited, because lithium-ion batteries usually require more than 800 cycles when the capacity decays to 80%.
  • Experimental Example 6 The difference between Experimental Example 6 and Experimental Example 3 is that when the pressure between the electrochemical device and the shell reaches the third threshold (0.5MPa), the charge and discharge cycle of the electrochemical device is stopped, and the number of cycles of the electrochemical device at this time is recorded. .
  • the third threshold 0.5MPa
  • the difference between Experimental Example 7-11 and Experimental Example 3 is that the setting of the second threshold is increased.
  • the pressure between the electrochemical device and the shell reaches the first threshold (0.08MPa) but does not reach the corresponding second threshold, Increase the first discharge cut-off voltage (3.0V) to the second discharge cut-off voltage (3.2V).
  • the pressure between the electrochemical device and the housing reaches the corresponding second threshold, further increase the discharge cut-off voltage by 0.2V. , that is, the second discharge cut-off voltage (3.2V) is raised to the third discharge cut-off voltage (3.4V).
  • the pressure between the electrochemical device and the case reaches the third threshold (0.5MPa)
  • Discharge cycle record the number of cycles of the electrochemical device at this time.
  • the second threshold corresponding to Experimental Example 7 is 0.10MPa
  • the second threshold corresponding to Experimental Example 8 is 0.15MPa
  • the second threshold corresponding to Experimental Example 9 is 0.20MPa
  • the second threshold corresponding to Experimental Example 10 is 0.25MPa.
  • the second threshold corresponding to Experimental Example 11 is 0.30MPa.
  • Table 5 below shows the test results of the number of cycles when the discharge cut-off voltage is raised to the second discharge cut-off voltage, the test results of the number of cycles when the discharge cut-off voltage is raised to the third discharge cut-off voltage, and the electrical Test results of the number of cycles when the chemical device stops charging and discharging.
  • the second threshold is set too small, it will cause the electrochemical device to stop charging and discharging when the cycle state of the electrochemical device is good, or send a message instructing to stop charging and discharging the electrochemical device, shortening the electrochemical process. Cycle life of the device. If the second threshold is set too large, the effect of increasing the cycle life of the electrochemical device and improving the safety performance of the electrochemical device will be relatively limited.
  • the charging cut-off voltage is reduced by 0.05V, and the electrochemical device
  • the charging cut-off voltage is adjusted to the second charging cut-off voltage (4.4V), where the first threshold corresponding to Experimental Example 12 is 0.01MPa, the first threshold corresponding to Experimental Example 13 is 0.05MPa, and the first threshold corresponding to Experimental Example 14 is 0.08MPa, the first threshold corresponding to Experimental Example 15 is 0.10MPa, and the first threshold corresponding to Experimental Example 16 is 0.15MPa.
  • Table 6 shows the test results of the number of cycles when the charging cut-off voltage is reduced and the number of cycles when the capacity decays to 80% in Comparative Example 5 and Experimental Examples 12-16.
  • the pressure between the electrochemical device and the case is less than the first threshold, it means that the irreversible expansion of the electrochemical device is small, the cycle performance of the electrochemical device and the pressure on the case are within a controllable range, and the initial charging cut-off voltage can be Perform charge and discharge cycles.
  • the first threshold is set to a small value (such as 0.01MPa in Experimental Example 12)
  • the electrochemical device will reduce the charging cut-off voltage after 50 cycles, which is not conducive to fully utilizing the energy density of the electrochemical device. .
  • the electrochemical device will only reduce the charging cut-off voltage after 400 cycles, which will improve the cycle life and irreversible expansion of the electrochemical device relatively. Limited, because for lithium-ion batteries, the number of cycles required to reach 80% capacity fading needs to be more than 800 times.
  • Experimental Example 17 The difference between Experimental Example 17 and Experimental Example 14 is that when the pressure between the electrochemical device and the shell reaches the third threshold (0.5MPa), the charge and discharge cycle of the electrochemical device is stopped, and the number of cycles of the electrochemical device at this time is recorded. .
  • the third threshold 0.5MPa
  • the difference between Experimental Examples 18-22 and Experimental Example 14 is that the setting of the second threshold is increased.
  • the pressure between the electrochemical device and the shell reaches the first threshold (0.08MPa) but does not reach the corresponding second threshold, Reduce the first charging cut-off voltage (4.45V) to the second charging cut-off voltage (4.4V).
  • the pressure between the electrochemical device and the housing reaches the corresponding second threshold, further reduce the charging cut-off voltage by 0.05V. , that is, the second charging cut-off voltage (4.5V) is reduced to the third charging cut-off voltage (4.35V).
  • the third threshold 0.5MPa
  • Discharge cycle record the number of cycles of the electrochemical device at this time.
  • the second threshold corresponding to Experimental Example 18 is 0.10MPa
  • the second threshold corresponding to Experimental Example 19 is 0.15MPa
  • the second threshold corresponding to Experimental Example 20 is 0.20MPa
  • the second threshold corresponding to Experimental Example 21 is 0.25MPa
  • the second threshold corresponding to Experimental Example 22 is 0.30MPa.
  • Table 7 below shows the test results of the number of cycles when the charge cut-off voltage is reduced to the second charge cut-off voltage, the test results of the number of cycles when the charge cut-off voltage is reduced to the third discharge cut-off voltage, and the test results of Experimental Examples 14 and 17-22. Test results of the number of cycles when the chemical device stops charging and discharging.
  • This method can improve the cycle life of the electrochemical device and reduce the irreversible volume expansion of the electrochemical device, thereby reducing the pressure damage of the electrochemical device to the shell.
  • the difference between Experimental Examples 23-26 and Experimental Example 21 is that the first discharge cut-off voltage is 3.0V, the first charge cut-off voltage is 4.45V, the first threshold is 0.08MPa, the second threshold is 0.25MPa, and the third threshold is 0.5 MPa.
  • the first discharge cut-off voltage 3.0V
  • the first charge cut-off voltage 4.45V
  • the first threshold 0.08MPa
  • the second threshold 0.25MPa
  • the third threshold is 0.5 MPa.
  • the corresponding first preset value of Experimental Example 21 is 0, and the corresponding second preset value is 0.05V.
  • the corresponding first preset value of Experimental Example 23 is 0.1V, and the corresponding second preset value is 0.05V.
  • the corresponding first preset value of Experimental Example 24 is 0.2V, and the corresponding second preset value is 0.
  • the corresponding first preset value of Experimental Example 25 is 0.2V, and the corresponding second preset value is 0.025V.
  • the corresponding first preset value of Experimental Example 26 is 0.2V, and the corresponding second preset value is 0.05V.
  • Table 8 below shows the test results of the number of cycles when the electrochemical devices of Experimental Example 21 and Experimental Examples 23-26 stop charging and discharging.
  • the discharge cut-off voltage needs to be increased and the charge cut-off voltage needs to be reduced, and the ratio of the first preset value and the second preset value needs to be balanced.
  • the first preset value is greater than the second preset value.

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Abstract

本申请实施例提供了一种电化学装置及其控制方法、电子设备和存储介质，该电化学装置的负极活性材料包括第一活性材料和第二活性材料，第一活性材料的克容量小于第二活性材料，第一活性材料的放电工作电压范围包括不大于第二活性材料的放电工作电压上限的第一电压范围，电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内；其中，第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压。本方案能够在提升电化学装置体积能量密度的前提下，使电化学装置具有较长的使用寿命。

Description

电化学装置及其控制方法、电子设备和存储介质 技术领域
本申请实施例涉及电化学技术领域，尤其涉及一种电化学装置及其控制方法、电子设备和存储介质。
背景技术
随着笔记本电脑、手机、平板电脑、移动电源和无人机等电子产品的普及，对其中电化学装置的要求越来越高。不仅要求电化学装置轻便，还要求电化学装置具有较高的体积能量密度和较长的使用寿命。锂离子电池、钠离子电池等二次电池，作为电子产品中常用的电化学装置。硅材料具有较高的可逆容量，因此硅被认为是有可能应用于二次电池的负极材料，以继续提高二次电池的体积能量密度。然而，硅负极材料在循环过程中体积会产生较大的膨胀，进而影响二次电池的使用寿命。
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控制方法、电子设备和存储介质，能够在提升电化学装置体积能量密度的前提下，使电化学装置具有较长的使用寿命。
根据本申请实施例的第一方面，提供了一种电化学装置，所述电化学装置的负极活性材料包括第一活性材料和第二活性材料，所述第一活性材料的克容量小于所述第二活性材料，所述第一活性材料的放电工作电压范围包括不大于所述第二活性材料的放电工作电压上限的第一电压范围，所述电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，所述电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，所述第一放电截止电压和所述第二放电截止电压均位于所述第一电压范围内；其中，所述第一放电截止电压小于所述第二放电截止电压，和/或，所述第一充电截止电压大于所述第二充电截止电压。
电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内，而放电截止电压位于第一电压范围内时，负极活性材料中有较多第一活性材料和较多第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压，通过调整第二活性材料贡献的容量，使得第二活性材料贡献的容量与电化学装置的健康状态相对应，延长电化学装置的使用寿命，因此能够在提高电化学装置体积能量密度的前提下，使电化学装置具有较长使用寿命。
在一种可能的实现方式中，所述第一活性材料的放电工作电压范围包括大于所述第二活性材料的放电工作电压上限的第二电压范围，所述电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行；其中，所述第三放电截止电压位于所述第二电压范围，和/或，所述第二充电截止电压大于所述第三充电截止电压。
第二电压范围内，而放电截止电压位于第二电压范围内时，负极活性材料中有较多第一 活性材料参与放电，而没有或仅有较少的第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第三放电截止电压位于第二电压范围，和/或，第二充电截止电压大于第三充电截止电压，可以使第二活性材料不参与电化学装置的放电过程，或仅有较少的第二活性材料参与电化学装置的放电过程，从而在第二活性材料发生较大的膨胀后，使第二活性材料不参与电化学装置的放电过程，从而抑制电化学装置的进一步膨胀，延长电化学装置的使用寿命。
在一种可能的实现方式中，所述电化学装置在第四时间段执行如下操作中的至少一个：(i)停止进行充放电；(ii)发出用于指示停止对所述电化学装置进行充放电操作的信息。
随着电化学装置的循环次数的增加，电化学装置的续航能力和安全性能会降低，影响用户的使用体验。由于第二活性材料在循环过程中会发生膨胀，随着电化学装置的循环次数增加，电化学装置的体积会产生较大的膨胀，电化学装置膨胀会增大电子设备损坏的风险。当电化学装置的续航能力和安全性能下降到一定程度，或电化学装置的体积膨胀到一定程度后，使电化学装置停止充放电，或发出用于指示停止对电化学装置进行充放电操作的信息，以提示用户更换电化学装置，可以提高用户的使用体验，而且可以提高电化学装置使用过程的安全性。
在一种可能的实现方式中，所述第一时间段、所述第二时间段、所述第三时间段和所述第四时间段在所述电化学装置的生命周期中按时间顺序依次排列。
第一时间段、第二时间段、第三时间段和第四时间段在电化学装置的生命周期中按时间顺序依次排列，电化学装置的放电截止电压按各时间段的时间顺序逐步提升，电化学装置的充电截止电压按各时间段的时间顺序逐步降低，在电化学装置循环的前期充分利用第二活性材料的高克容量优势，提高电化学装置的体积能量密度，在电化学装置循环的后期减少第二活性材料贡献的容量，降低电化学装置的膨胀速度，延长电化学装置的使用寿命，最终停止对电化学装置进行充放电操作或提示停止对电化学装置进行充放电操作，提高用户对于电化学装置的使用体验，并保证电化学装置所在电子设备的安全性。
在一种可能的实现方式中，所述第二活性材料包括硅，所述第一电压范围为不大于3.5V，所述第二电压范围为大于3.5V。
当第二活性材料包括硅时，在电化学装置的放电过程中，放电电压位于3.5V以上时，主要由第一活性材料参与电化学装置的放电过程，没有或仅有少量第二活性材料参与电化学装置的放电过程，而在放电电压位于3.5V以下时，第一活性材料和第二活性材料均会以较多的量参与电化学装置的放电过程。第一电压范围和第二电压范围以3.5V作为分界点，在第一时间段可以充分利用第二活性材料的高克容量性能，提高电化学装置的体积能量密度，在第二时间段可以减缓电化学装置的膨胀速度，延长电化学装置的使用寿命。
在一种可能的实现方式中，所述电化学装置在不同的时间段运行时，所述电化学装置的健康状态(State Of Health，SOH)参数位于不同的取值范围。
电化学装置在不同的时间段运行时，电化学装置的SOH参数位于不同的取值范围，即第一时间段、第二时间段、第三时间段和第四时间段可以根据电化学装置的SOH参数确定。由于SOH参数用于表征电化学装置的健康状态，根据SOH参数确定电化学装置运行的各时间 段，即为根据电化学装置的健康状态确定电化学装置运行的各时间段，使电化学装置在不同时间段内以不同的放电截止电压和/或充电截止电压运行，在充分利用第二活性材料高克容量性能，提高电化学装置体积容量密度的同时，保证电化学装置具有较长的使用寿命。
在一种可能的实现方式中，所述SOH参数包括如下各项中的至少一个：(i)所述电化学装置的内阻；(ii)所述电化学装置的可逆容量；(iii)所述电化学装置的厚度；(iiii)所述电化学装置与用于装容所述电化学装置的壳体之间的压力或压强。
电化学装置的循环过程中，电化学装置的内阻、可逆容量、厚度、与壳体之间的压力或压强，均可以反映电化学装置的健康状态，将电化学装置的内阻、可逆容量、厚度、与壳体之间的压力或压强中的一个或多个作为SOH参数，使得SOH参数可以准确地反映电化学装置的健康状态，进而根据SOH参数确定不同的时间段，通过调整电化学装置在不同时间段内的放电截止电压和充电截止电压，充分利用第二活性材料的高克容量性能，在提高电化学装置的体积能量密度的前提下，延长电化学装置的使用寿命。
在一种可能的实现方式中，所述SOH参数为所述电化学装置与所述壳体之间的压强；当所述电化学装置与所述壳体之间的压强小于第一阈值时，所述电化学装置在所述第一时间段运行；当所述电化学装置与所述壳体之间的压强大于或等于所述第一阈值且小于第二阈值时，所述电化学装置在所述第二时间段运行；当所述电化学装置与所述壳体之间的压强大于或等于所述第二阈值且小于第三阈值时，所述电化学装置在所述第三时间段运行；当所述电化学装置与所述壳体之间的压强大于或等于所述第三阈值时，所述电化学装置在所述第四时间段运行。
使电化学装置与壳体之间的压强不断增大，因此可以通过依次增大的第一阈值、第二阈值和第三阈值，将电化学装置的生命周期划分为四个时间段，在前三个时间段内电化学装置以不同的放电截止电压和/或充电截止电压运行，在提高电化学装置体积容量密度的前提下，减缓电化学装置的膨胀速度，延长电化学装置的使用寿命，在最后一个时间段停止对电化学装置进行充放电操作或提示停止对电化学装置进行充放电操作，提高用于对于电化学装置的使用体验。
在一种可能的实现方式中，所述第一阈值大于或等于0.03MPa，所述第二阈值小于0.5MPa，所述第三阈值大于或等于0.5Mpa，所述第二阈值大于所述第一阈值。
设定第一阈值大于或等于0.03MPa，第二阈值小于0.5MPa，第三阈值大于或等于0.5MPa，通过第一阈值、第二阈值和第三阈值将电化学装置的生命周期划分为四个时间段，电化学装置在前三个时间段以不同的放电截止电压和/或充电截止电压运行，在充分利用电化学装置的能量密度的同时，减缓电化学装置的循环状态的恶化，延长电化学装置的使用寿命。在最后一个时间段停止对电化学装置进行充放电操作，或提示用户提示对电化学装置进行充放电操作，可以避免电化学装置由于不可逆膨胀过大而对壳体造成挤压损伤。
在一种可能的实现方式中，所述电化学装置的负极活性材料中硅的质量占比位于(0％,60％]范围内。
硅作为第二活性材料时，随着负极活性材料中硅含量的增加，电化学装置的体积能量密度增加，但电化学装置的循环寿命衰减，使负极活性材料中硅的质量占比小于或等于60％， 可以在提高电化学装置的体积能量密度，而且不会使电化学装置的循环寿命过分衰减，进而通过控制电化学装置在不同时间段内以不同的放电截止电压和/或充电截止电压运行，可以实现在提高电化学装置体积能量密度的前提下，保证电化学装置具有较长的循环寿命。
在一种可能的实现方式中，所述电化学装置的负极活性材料中硅的质量占比位于[10％,20％]范围内。
硅作为第二活性材料时，负极活性材料中硅的质量占比位于[10％,20％]范围时，基于硅的高克容量特性，可以提高电化学装置的体积能量密度，由于硅的质量占比小于或等于20％，对电化学装置的循环性能不会造成显著的影响，通过控制电化学装置在不同时间段以不同的放电截止电压和/或充电截止电压运行，在充分利用电化学装置的能量密度的同时，保证电化学装置具有较长的循环寿命。
根据本申请实施例的第二方面，提供了一种电化学装置控制方法，用于对电化学装置的充放电过程进行控制，所述电化学装置的负极活性材料包括第一活性材料和第二活性材料，所述第一活性材料的克容量小于所述第二活性材料，所述第一活性材料的放电工作电压范围包括不大于所述第二活性材料的放电工作电压上限的第一电压范围，所述电化学装置控制方法包括：控制所述电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，所述第一放电截止电压位于所述第一电压范围内；控制所述电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，所述第二放电截止电压位于所述第一电压范围内；其中，所述第一放电截止电压小于所述第二放电截止电压，和/或，所述第一充电截止电压大于所述第二充电截止电压。
在第一时间段内控制电化学装置以第一放电截止电压和第一充电截止电压运行，在第二时间段内控制电化学装置以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内，而放电截止电压位于第一电压范围内时，负极活性材料中有较多第一活性材料和较多第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压，进而调整第二活性材料贡献的容量，使得第二活性材料贡献的容量与电化学装置的健康状态相对应，延长电化学装置的使用寿命，因此能够在提高电化学装置体积能量密度的前提下，使电化学装置具有较长使用寿命。
在一种可能的实现方式中，所述第一活性材料的放电工作电压范围包括大于所述第二活性材料的放电工作电压上限的第二电压范围，所述电化学装置控制方法还包括：控制所述电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行；其中，所述第三放电截止电压位于所述第二电压范围，和/或，所述第二充电截止电压大于所述第三充电截止电压。
在一种可能的实现方式中，所述电化学装置控制方法还包括：在第四时间段控制所述电化学装置执行如下操作中的至少一个：(i)停止进行充放电；(ii)发出用于指示停止对所述电化学装置进行充放电操作的信息。
在一种可能的实现方式中，所述第一时间段、所述第二时间段、所述第三时间段和所述第四时间段在所述电化学装置的生命周期中按时间顺序依次排列。
在一种可能的实现方式中，所述电化学装置控制方法还包括：根据所述电化学装置的SOH 参数所处的取值范围，确定所述电化学装置所在的时间段。
在一种可能的实现方式中，所述SOH参数包括如下各项中的至少一个：(i)所述电化学装置的内阻；(ii)所述电化学装置的可逆容量；(iii)所述电化学装置的厚度；(iiii)所述电化学装置与用于装容所述电化学装置的壳体之间的压力或压强。
在一种可能的实现方式中，所述电化学装置的负极活性材料中硅的质量占比位于(0％,60％]范围内。
在一种可能的实现方式中，所述电化学装置的负极活性材料中硅的质量占比位于[10％,20％]范围内。
根据本申请实施例的第三方面，提供了一种电化学装置管理系统，所述电化学装置管理系统与电化学装置连接，所述电化学装置管理系统用于执行上述第二方面或第二方面的任一可能实现方式提供的电化学装置控制方法。
根据本申请实施例的第四方面，提供了一种电子设备，包括上述第一方面或第一方面的任一可能实现方式提供的电化学装置，或者包括上述第三方面提供的电化学装置管理系统。
根据本申请实施例的第五方面，提供了一种计算机可读存储介质，所述计算机可读存储介质上存储有计算机程序，所述计算机程序被处理器执行时实现如上述第二方面或第二方面的任一可能实现方式提供的电化学装置控制方法。
由上述技术方案可知，电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内，而放电截止电压位于第一电压范围内时，负极活性材料中有较多第一活性材料和较多第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压，通过调整第二活性材料贡献的容量，使得第二活性材料贡献的容量与电化学装置的健康状态相对应，延长电化学装置的使用寿命，因此能够在提高电化学装置体积能量密度的前提下，使电化学装置具有较长使用寿命。
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是本申请一个实施例的电化学装置对壳体压力检测的示意图；
图2是本申请一个实施例的电化学装置膨胀及对壳体压强随循环次数的变化曲线示意图；
图3是本申请一个实施例的电化学装置控制方法的流程图。
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、详细地描述，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。
在下面的描述中，先对本申请实施例中的电化学装置其控制方法、电子设备和存储介质进行具体说明，然后给出本申请实施例中的电化学装置及其控制方法的一些相关的实验例和对比例，用于说明本申请实施例中的电化学装置及其控制方法、电子设备和存储介质相对于现有技术的显著优势。
下面结合附图说明本申请实施例的具体优势。
需要说明的是，在本申请实施例的内容中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
电化学装置
电化学装置为笔记本电脑、手机、平板电脑、移动电源和无人机等电子产品提供电能。锂离子电池、钠离子电池等均采用石墨负极体系，随着对电子设备重量、体积和续航能力的要求不能提升，需要提升电化学装置的体积能量密度。硅、磷等具有较大克容量的材料具有较高的可逆容量，因此将硅、磷等材料应用于电化学装置的负极材料，可以继续提高电化学装置的体积能量密度，但是较大克容量的负极材料在循环过程中会产生较大的膨胀，影响电化学装置的使用寿命。因此，需要一种能够提高电化学装置的体积能量密度，而且保证电化学装置具有较长使用寿命的技术方案。
本申请实施例提供了一种电化学装置，该电化学装置的负极活性材料包括第一活性材料和第二活性材料，第一活性材料的克容量小于第二活性材料，第一活性材料的放电工作电压范围包括不大于第二活性材料的放电工作电压上限的第一电压范围。电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内。其中，第一放电截止电压小于第二截止电压，和/或，第一充电截止电压大于第二充电截止电压。
克容量是指电池内部活性材料所能释放出的电容量与活性材料的质量之比，克容量的单位为毫安时每克(mA·h/g)。第一活性材料的克容量小于第二活性材料，相同质量的第一活性材料和第二活性材料作为电池的负极活性材料时，第一活性材料所能释放出的电量小于第二活性材料所能释放出的电量。
第一活性材料可以是石墨、中间相炭微球(Mesocarbon microbeads，MCMB)或Li 4Ti 5O 12等，第二活性材料可以是SiO x(0<x<2)、微米硅、硅纳米线、SiC、过渡金属氧化物(如MnO、SnO 2、CoO等)或磷等。上述第一活性材料和第二活性材料可以自由组合，电化学装置的负极活性材料可以包括多种第一活性材料和/或多种第二活性材料。
第二活性材料具有放电工作电压范围，在该放电工作电压范围内，第一活性材料和第二活性材料均贡献较大的容量。在第二活性材料的放电工作电压范围的上限以上，主要由第一活性材料贡献容量，也会有少量第二活性材料贡献容量，比如第一活性材料贡献的容量大于80％。在第二活性材料的放电工作电压范围的上限以下，主要由第二活性材料贡献容量，也会有少量第一活性材料贡献容量，比如第二活性材料贡献的容量大于80％。
第一活性材料的防电工作电压范围包括不大于第二活性材料的放电工作电压上限的第一电压范围，第二活性材料的放电工作电压上限是指第二活性材料的放电工作电压范围的上限， 比如第二活性材料的放电工作电压范围为[2.3V,3.5V]，第二活性材料的放电工作电压上限为3.5V，第一电压范围为[2.3V,3.5V]。第一电压范围不大于第二活性材料的放电工作电压上限，即第一电压范围内任一电压取值小于或等于第二活性材料的放电工作电压上限。在第一电压范围内，第一活性材料和第二活性材料均贡献较大的容量，即在电化学装置的放电电压位于第一电压范围内时，较多的第一活性材料和较多的第二活性材料参与电化学装置的放电过程，第一电压范围可以与第二活性材料的放电工作电压范围相同。
第一时间段和第二时间段可以是电化学装置的整个生命周期中的第一循环阶段和第二循环阶段，即第一时间段和第二时间段对应电化学装置的不同充放电循环，比如第一时间段为电化学装置的第300个充放电循环至第450个充放电循环，第二时间段为电化学装置的第451个充放电循环至第600个充放电循环。第一时间段和第二时间段可以包括电化学装置的一个或多个充放电循环，第一时间段和第二时间段所包括充放电循环的次数可以相同，也可以不同。
在本申请实施例中，电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内，而放电截止电压位于第一电压范围内时，负极活性材料中有较多第一活性材料和较多第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压，通过调整第二活性材料贡献的容量，使得第二活性材料贡献的容量与电化学装置的健康状态相对应，延长电化学装置的使用寿命，因此能够在提高电化学装置体积能量密度的前提下，使电化学装置具有较长使用寿命。
在一种可能的实现方式中，第一活性材料的放电工作电压范围包括大于第二活性材料的放电工作电压上限的第二电压范围，电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行。其中，第三放电截止电压位于第二电压范围内，和/或，第二充电截止电压大于第三充电截止电压。
第一活性材料的放电工作电压范围不仅包括第一电压范围，还包括大于第二活性材料的放电工作电压上限的第二电压范围，比如第二活性材料的放电工作电压范围为[2.3V,3.5V]，第二活性材料的放电工作电压上限为3.5V，第二电压范围为(3.5V,4.5V]。第二电压范围大于第二活性材料的放电工作电压上限，即第二电压范围内任一电压取值大于第二活性材料的放电工作电压上限。由于第二电压范围大于第二活性材料的放电工作电压上限，所以在第二电压范围内，主要由第一活性材料贡献容量，第二活性材料不贡献容量或仅贡献少量容量，比如第一活性材料贡献的容量大于80％，即在电化学装置的放电电压位于第二电压范围内时，较多的第一活性材料参与电化学装置的放电过程，而较少的第二活性材料或没有第二活性材料参与电化学装置的放电过程。
由于第一放电截止电压和第二放电截止电压位于第一电压范围内，第三放电截止电压位于第二电压范围内，第一电压范围不大于第二活性材料的放电工作电压上限，第二电压范围大于第二活性材料的放电工作电压上限，所以第三放电截止电压大于第一放电截止电压和第二放电截止电压。
在本申请实施例中，电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行，第三放电截止电压位于第二电压范围内，而放电截止电压位于第二电压范围内时，负极活性材料中有较多第一活性材料参与放电，而没有或仅有较少的第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第三放电截止电压位于第二电压范围，和/或，第二充电截止电压大于第三充电截止电压，可以使第二活性材料不参与电化学装置的放电过程，或仅有较少的第二活性材料参与电化学装置的放电过程，从而在第二活性材料发生较大的膨胀后，使第二活性材料不参与电化学装置的放电过程，从而抑制电化学装置的进一步膨胀，延长电化学装置的使用寿命。
在一种可能的实现方式中，电化学装置可以在第四时间段执行如下操作中的至少一个：
(i)停止进行充放电；
(ii)发出用于指示停止对电化学装置进行充放电操作的信息。
在本申请实施例中，随着电化学装置的循环次数的增加，电化学装置的续航能力和安全性能会降低，影响用户的使用体验。由于第二活性材料在循环过程中会发生膨胀，随着电化学装置的循环次数增加，电化学装置的体积会产生较大的膨胀，电化学装置膨胀会增大电子设备损坏的风险。当电化学装置的续航能力和安全性能下降到一定程度，或电化学装置的体积膨胀到一定程度后，使电化学装置停止充放电，或发出用于指示停止对电化学装置进行充放电操作的信息，以提示用户更换电化学装置，可以提高用户的使用体验，而且可以提高电化学装置使用过程的安全性。
在一种可能的实现方式中，第一时间段、第二时间段、第三时间段和第四时间段在电化学装置的生命周期中按时间顺序依次排列。
在第一时间段和第二时间段内，第一活性材料和第二活性材料均参与电化学装置的放电过程，充分利用第二活性材料的高克容量优势，随着循环次数的增加，第二活性材料逐渐膨胀，通过提高放电截止电压可以减少放电过程中第二活性材料的参与程度，降低电化学装置的膨胀速度。在第三时间段内，主要是第一活性材料参与电化学装置的放电过程，由于第二活性材料循环过程的膨胀大于第一活性材料，在电化学装置已经发生了较大体积的膨胀后，进一步提高电化学装置的放电截止电压，可以使第二活性材料不参与电化学装置的放电过程，从而进一步降低电化学装置的膨胀速度，以延长电化学装置的使用寿命。在第四时间段，电化学装置的膨胀程度已经影响电子设备的安全性，使电化学装置停止充放电操作或提示停止对电化学装置进行充放电操作，可以提高用户的使用体验，并保证电化学装置所在电子设备的安全性。
与提高电化学装置的放电截止电压相对应，降低电化学装置的充电截止电压，也可以减小电化学装置循环过程中第二活性材料的参与程度，从而降低电化学装置的膨胀速度，延长电化学装置的使用寿命。
在本申请实施例中，第一时间段、第二时间段、第三时间段和第四时间段在电化学装置的生命周期中按时间顺序依次排列，电化学装置的放电截止电压按各时间段的时间顺序逐步提升，电化学装置的充电截止电压按各时间段的时间顺序逐步降低，在电化学装置循环的前期充分利用第二活性材料的高克容量优势，提高电化学装置的体积能量密度，在电化学装置 循环的后期减少第二活性材料贡献的容量，降低电化学装置的膨胀速度，延长电化学装置的使用寿命，最终停止对电化学装置进行充放电操作或提示停止对电化学装置进行充放电操作，提高用户对于电化学装置的使用体验，并保证电化学装置所在电子设备的安全性。
在一种可能的实现方式中，第二活性材料包括硅，第一电压范围为不大于3.5V，第二电压范围为大于3.5V。
在本申请实施例中，当第二活性材料包括硅时，在电化学装置的放电过程中，放电电压位于3.5V以上时，主要由第一活性材料参与电化学装置的放电过程，没有或仅有少量第二活性材料参与电化学装置的放电过程，而在放电电压位于3.5V以下时，第一活性材料和第二活性材料均会以较多的量参与电化学装置的放电过程。第一电压范围和第二电压范围以3.5V作为分界点，在第一时间段可以充分利用第二活性材料的高克容量性能，提高电化学装置的体积能量密度，在第二时间段可以减缓电化学装置的膨胀速度，延长电化学装置的使用寿命。
在一种可能的实现方式中，电化学装置在不同的时间段运行时，电化学装置的健康状态(State Of Health，SOH)参数位于不同的取值范围。
在本申请实施例中，电化学装置在不同的时间段运行时，电化学装置的SOH参数位于不同的取值范围，即第一时间段、第二时间段、第三时间段和第四时间段可以根据电化学装置的SOH参数确定。由于SOH参数用于表征电化学装置的健康状态，根据SOH参数确定电化学装置运行的各时间段，即为根据电化学装置的健康状态确定电化学装置运行的各时间段，使电化学装置在不同时间段内以不同的放电截止电压和/或充电截止电压运行，在充分利用第二活性材料高克容量性能，提高电化学装置体积容量密度的同时，保证电化学装置具有较长的使用寿命。
在一种可能的实现方式中，电化学装置的SOH参数可以包括如下各项中的至少一个：
(i)电化学装置的内阻；
(ii)电化学装置的可逆容量；
(iii)电化学装置的厚度；
(iiii)电化学装置与用于装容电化学装置的壳体之间的压力或压强。
在本申请实施例中，电化学装置的循环过程中，电化学装置的内阻、可逆容量、厚度、与壳体之间的压力或压强，均可以反映电化学装置的健康状态，将电化学装置的内阻、可逆容量、厚度、与壳体之间的压力或压强中的一个或多个作为SOH参数，使得SOH参数可以准确地反映电化学装置的健康状态，进而根据SOH参数确定不同的时间段，通过调整电化学装置在不同时间段内的放电截止电压和充电截止电压，充分利用第二活性材料的高克容量性能，在提高电化学装置的体积能量密度的前提下，延长电化学装置的使用寿命。
随着电化学装置循环次数的增加，负极活性材料的体积会发生膨胀，进而使电化学装置的厚度增加，因此可以将电化学装置的厚度作为反映电化学装置健康状态的SOH参数。当电化学装置位于电子设备的壳体内时，比如电化学装置位于手机外壳内部时，电化学装置的膨胀会改变其与壳体之间的压力和压强，因此可以将电化学装置与用户装容该电化学装置的壳体之间的压力或压强，作为反映电化学装置的健康状态的SOH参数。
图1是本申请一个实施例的电化学装置对壳体压力检测的示意图。如图1所示，电化学 装置11设置于壳体12内，在电化学装置11与壳体12的下侧壁之间设置有压力传感器13。随着电化学装置11循环次数的增加，电化学装置11的体积发生膨胀，当电化学装置11膨胀至与壳体12的上侧壁相接触后，随着电化学装置11体积的进一步膨胀，电化学装置11对壳体12的压力增大，从而根据压力传感器13检测到的压力值，可以确定电化学装置11的膨胀程度。进一步地，电化学装置管理系统获取到压力传感器13检测到的压力值后，除以压力传感器13与电化学装置11的接触面积，便可以确定电化学装置11与壳体12之间的压强。
在一种可能的实现方式中，SOH参数为电化学装置与壳体之间的压强时，针对的电化学装置与壳体之间的压强设置有第一阈值、第二阈值和第三阈值，第一阈值小于第二阈值，第二阈值小于第三阈值。当电化学装置与壳体之间的压强小于第一阈值时，电化学装置在第一时间段运行。当电化学装置与壳体之间的压强大于或等于第一阈值且小于第二阈值时，电化学装置在第二时间段运行。当电化学装置与壳体之间的压强大于或等于第二阈值且小于第三阈值时，电化学装置在第三时间段运行。当电化学装置与壳体之间的压强大于或等于第三压强时，电化学装置在第四时间段运行。
图2是本申请一个实施例的电化学装置膨胀及对壳体压强随循环次数的变化曲线。如图2所示，曲线201为电化学装置的膨胀百分比随循环次数的变化曲线，曲线202为电化学装置对壳体的压强随循环次数的变化曲线。由曲线201可知，随电化学装置循环次数的增加，电化学装置的膨胀百分比逐渐增大，即电化学装置的体积逐渐增大，电化学装置的健康状况不断恶化。由曲线202可知，随着电化学装置循环次数的增加，电化学装置对壳体的压强逐渐增大。由图1可见，电化学装置的膨胀百分比与电化学装置对壳体的压强正相关，而电化学装置的膨胀程度可以反映健康状态，因此可以根据电化学装置对壳体的压强，将电化学装置的生命周期划分为多个时间段，不同时间段电化学装置的健康状态不同，通过调整不同时间段内电化学装置的放电截止电压和充电截止电压，以在提高电化学装置体积容量密度的同时，保证电化学装置的使用寿命。
在本申请实施例中，随着电化学装置循环次数的增加，电化学装置的健康状态不断恶化，电化学装置的体积不断膨胀，使电化学装置与壳体之间的压强不断增大，因此可以通过依次增大的第一阈值、第二阈值和第三阈值，将电化学装置的生命周期划分为四个时间段，在前三个时间段内电化学装置以不同的放电截止电压和/或充电截止电压运行，在提高电化学装置体积容量密度的前提下，减缓电化学装置的膨胀速度，延长电化学装置的使用寿命，在最后一个时间段停止对电化学装置进行充放电操作或提示停止对电化学装置进行充放电操作，提高用于对于电化学装置的使用体验。
在一种可能的实现方式中，针对电化学装置与壳体之间压强所设置的第一阈值、第二阈值和第三阈值，第一阈值大于或等于0.03MPa，第二阈值小于0.5MPa，第三阈值大于或等于0.5MPa。
设定第一阈值大于或等于0.03MPa且小于0.5MPa，使得电化学装置在循环状态较好时以较低放电截止电压和/或较高充电截止电压运行，充分利用电化学装置的能量密度。设定第二阈值大于第一阈值且小于0.5MPa，在电化学装置的循环状态出现一定程度的恶化后，提高电化学装置的放电截止电压和/或降低电化学装置的充电截止电压，避免电化学装置由于不可逆 膨胀多大而导致循环寿命恶化严重。设定第三阈值大于或等于0.5MPa，保证电化学装置在循环状态较好时能够充放电，充分利用电化学装置的能量密度，并且在电化学装置产生较大膨胀时停止对电化学装置进行充放电操作，避免电化学装置因不可逆膨胀过大而对壳体造成挤压损伤。
在本申请实施例中，设定第一阈值大于或等于0.03MPa，第二阈值小于0.5MPa，第三阈值大于或等于0.5MPa，通过第一阈值、第二阈值和第三阈值将电化学装置的生命周期划分为四个时间段，电化学装置在前三个时间段以不同的放电截止电压和/或充电截止电压运行，在充分利用电化学装置的能量密度的同时，减缓电化学装置的循环状态的恶化，延长电化学装置的使用寿命。在最后一个时间段停止对电化学装置进行充放电操作，或提示用户提示对电化学装置进行充放电操作，可以避免电化学装置由于不可逆膨胀过大而对壳体造成挤压损伤。
在一种可能的实现方式中，电化学装置的负极活性材料中硅的质量占比位于(0％,60％]范围内，比如，负极活性材料中的硅的质量占比为1％、10％、20％、30％或60％等。
在本申请实施例中，硅作为第二活性材料时，随着负极活性材料中硅含量的增加，电化学装置的体积能量密度增加，但电化学装置的循环寿命衰减，使负极活性材料中硅的质量占比小于或等于60％，可以在提高电化学装置的体积能量密度，而且不会使电化学装置的循环寿命过分衰减，进而通过控制电化学装置在不同时间段内以不同的放电截止电压和/或充电截止电压运行，可以实现在提高电化学装置体积能量密度的前提下，保证电化学装置具有较长的循环寿命。
在一种可能的实现方式中，电化学装置的负极活性材料中硅的质量占比位于[10％,20％]范围内，比如，负极活性材料中硅的质量占比为1％、10％或20％等。
在本申请实施例中，硅作为第二活性材料时，负极活性材料中硅的质量占比位于[10％,20％]范围时，基于硅的高克容量特性，可以提高电化学装置的体积能量密度，由于硅的质量占比小于或等于20％，对电化学装置的循环性能不会造成显著的影响，通过控制电化学装置在不同时间段以不同的放电截止电压和/或充电截止电压运行，在充分利用电化学装置的能量密度的同时，保证电化学装置具有较长的循环寿命。
电化学装置控制方法
图3是本申请一个实施例的电化学装置控制方法的流程图，用于对电化学装置的充放电过程进行控制，电化学装置的负极活性材料包括第一活性材料和第二活性材料，第一活性材料的克容量小于第二活性材料，第一活性材料的放电工作电压范围包括不大于第二活性材料的放电工作电压上限的第一电压范围。如图3所示，该电化学装置控制方法包括如下步骤：
步骤301、控制电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行。
在电化学装置的生命周期中包括第一时间段，控制电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，其中，第一放电截止电压位于第一电压范围内。
步骤302、控制电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行。
在电化学装置的生命周期中包括与第一时间段不同的第二时间段，控制电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，其中，第二放电截止电压位于第一电压范围内，而且第一放电截止电压小于第二放电截止电压和/或第一充电截止电压大于第二 充电截止电压。
在本申请实施例中，在第一时间段内控制电化学装置以第一放电截止电压和第一充电截止电压运行，在第二时间段内控制电化学装置以第二放电截止电压和第二充电截止电压运行，第一放电截止电压和第二放电截止电压均位于第一电压范围内，而放电截止电压位于第一电压范围内时，负极活性材料中有较多第一活性材料和较多第二活性材料参与放电，通过调整电化学装置的放电截止电压和充电截止电压，使第一放电截止电压小于第二放电截止电压，和/或，第一充电截止电压大于第二充电截止电压，进而调整第二活性材料贡献的容量，使得第二活性材料贡献的容量与电化学装置的健康状态相对应，延长电化学装置的使用寿命，因此能够在提高电化学装置体积能量密度的前提下，使电化学装置具有较长使用寿命。
在一种可能的实现方式中，第一活性材料的放电工作电压范围包括大于第二活性材料的放电工作电压上限的第二电压范围，此时电化学装置控制方法还包括：
控制电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行。其中，第三放电截止电压位于第二电压范围，和/或，第二充电截止电压大于第三充电截止电压。
在一种可能的实现方式中，电化学装置控制方法还包括：在第四时间段控制电化学装置执行如下操作中的至少一个：
(i)停止进行充放电；
(ii)发出用于指示停止对电化学装置进行充放电操作的信息。
在一种可能的实现方式中，在电化学装置的生命周期包括上述第一时间段、第二时间段、第三时间段和第四时间段时，第一时间段、第二时间段、第三时间段和第四时间段在电化学装置的生命周期中按时间顺序依次排列。
在一种可能的实现方式中，电化学装置控制方法还包括：根据电化学装置的健康状态参数所处的取值范围，确定电化学装置所在的时间段。
在一种可能的实现方式中，健康状态参数包括如下各项中的至少一个：(i)电化学装置的内阻；(ii)电化学装置的可逆容量；(iii)电化学装置的厚度；(iiii)电化学装置与用于装容电化学装置的壳体之间的压力或压强。
在一种可能的实现方式中，电化学装置的负极活性材料中硅的质量占比位于(0％,60％]范围内。
在一种可能的实现方式中，电化学装置的负极活性材料中硅的质量占比位于[10％,20％]范围内。
需要说明的是，由于上述电化学装置控制方法的细节在上述本申请实施例的电化学装置实施例中，已经进行了详细说明，具体过程可参见前述电化学装置实施例中的描述，在此不再赘述。
电化学装置管理系统
本申请一个实施例提供了一种电化学装置管理系统，该电化学装置管理系统与电化学装置连接，该电化学装置管理系统用于执行前述实施例中的电化学装置控制方法。
需要说明的是，由于前述实施例中已经对电化学装置和电化学装置控制方法进行了详细说明，电化学装置管理系统控制电化学装置运行的过程可以参照前述实施例中的描述，在此 不再进行赘述。
电子设备
本申请一个实施例提供了一种电子设备，包括上述实施例中的电化学装置或电化学装置管理系统。电子设备可以是手机、无人机等。电子设备中的电化学装置的负极活性材料包括第一活性材料和第二活性材料，第一活性材料的克容量小于第二活性材料，由于第二活性材料的存在可以提高电化学装置的体积能量密度，使电子设备具有更强的续航能力。控制电子设备中的电化学装置在不同的时间段以不同的放电截止电压和/或充电截止电压运行，可以减缓电化学装置循环寿命的衰减，从而延长电化学装置的使用寿命，提高用户对于电子设备的使用体验。
计算机可读存储介质
本申请还提供了一种计算机可读存储介质，该计算机可读存储介质上存储有计算机程序，计算机程序被处理器执行时实现上述任一实施例中的电化学装置控制方法。具体地，可以提供配有存储介质的系统或者装置，在该存储介质上存储着实现上述实施例中任一实施例的功能的软件程序代码，且使该系统或者装置的计算机(或CPU或MPU)读出并执行存储在存储介质中的程序代码。
在这种情况下，从存储介质读取的程序代码本身可实现上述实施例中任何一项实施例的功能，因此程序代码和存储程序代码的存储介质构成了本申请的一部分。
用于提供程序代码的存储介质实施例包括软盘、硬盘、磁光盘、光盘(如CD-ROM、CD-R、CD-RW、DVD-ROM、DVD-RAM、DVD-RW、DVD+RW)、磁带、非易失性存储卡和ROM。可选择地，可以由通信网络从服务器计算机上下载程序代码。
此外，应该清楚的是，不仅可以通过执行计算机所读出的程序代码，而且可以通过基于程序代码的指令使计算机上操作的操作系统等来完成部分或者全部的实际操作，从而实现上述实施例中任意一项实施例的功能。
此外，可以理解的是，将由存储介质读出的程序代码写到插入计算机内的扩展板中所设置的存储器中或者写到与计算机相连接的扩展模块中设置的存储器中，随后基于程序代码的指令使安装在扩展板或者扩展模块上的CPU等来执行部分和全部实际操作，从而实现上述实施例中任一实施例的功能。
计算机程序产品
本申请实施例还提供了一种计算机程序产品，该计算机程序产品被存储在计算机可读介质上并且包括计算机可执行指令，所述计算机可执行指令在被执行时使至少一个处理器执行上述任一实施例中的电化学装置控制方法。应理解，本实施例中的各方案具有上述方法实施例中对应的技术效果，此处不再赘述。
实验例和对比例
下面以锂离子电池作为电化学装置为例，对本申请实施例的一些实验例和对比例进行具体说明，通过这些实验例和对比例，可以更方便地看出本申请实施例中电化学装置及其控制方法、电子设备和存储介质相对于现有技术的显著优势。应当理解，下述实验例和对比例仅用于对本申请实施例进行更好地说明，而并非对本申请实施例的限制。
<对比例1>
正极极片的制备：将正极活性材料钴酸锂、导电炭黑(SuperP)、聚偏二氟乙烯(PVDF)按照重量比97：1.4：1.6进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，搅拌均匀形成正极浆料(固含量为72wt％)。将正极浆料均匀涂覆在正极集流体铝箔上，涂覆厚度为80μm，在85℃下烘干，然后经过冷压、裁片、分切后，在85℃的真空条件下干燥4小时，得到正极极片。
负极极片的制备：将人造石墨、粘结剂聚丙烯酸和羧甲基纤维素钠(CMC)按重量比97：1.5：1.5溶于去离子水中，形成负极浆料(固含量为40wt％)。采用10μm厚度铜箔作为负极集流体，将负极浆料涂覆于负极的集流体上，涂覆厚度为50μm，在85℃下烘干，然后经过冷压、裁片、分切后，在120℃的真空条件下干燥12小时，得到负极极片。
隔离膜的制备：隔离膜为7μm厚的聚乙烯(PE)。
电解液的制备：在干燥的氩气气氛手套箱中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按照质量比为EC：PC：DEC＝1：1：1进行混合，溶解并充分搅拌后加入锂盐LiPF 6，混合均匀后获得电解液，其中LiPF 6的浓度为1mol/L。
锂离子电池的制备：将正极极片、隔离膜、负极极片按顺序依次叠好，使隔离膜处于正极和负极中间，起到隔离的作用，并卷绕得到电极组件。将电极组件置于外包装铝塑膜中，在80℃下脱去水分后，注入上述电解液并封装，经过化成、脱气、切边等工艺流程得到锂离子电池。
循环条件：采用单一循环条件不变化，其中，放电截止电压为3.0V，充电截止电压为4.45V。
下面描述本申请各实施例中参数的测试方法。
(1)充电截止电压和放电截止电压的测试：可使用电池电压内阻测试仪或者万用表测试。
(2)电化学装置(锂离子电池)与壳体之间压强的测试：如图1所示，壳体内置压力传感器，随着电化学装置循环次数的增加发生不可逆膨胀，电化学装置接触壳体和压力传感器后形成一定压力，该压力的数值处于传感器与电化学装置的接触面积为电化学装置与壳体之间的压强。由图2可知，电化学装置与壳体之间的压强，与电化学装置循环中膨胀体积存在一一对应关系。
(3)电化学装置循环数测试：通过循环测试仪器对电池单体按照设置的充放电截止电压进行恒流恒压充放电测试。例如，一单体电池的充放电截止电压分别为4.45V和3.0V，循环测试仪在25℃下以3C恒流恒压充电到4.45V，再以0.5C放电到3.0V作为一次循环，不断反复测试作为单体电池的不同循环数。容量衰减至80％时的循环数测试：对化成后的电池单体进行在25℃下以3C恒流恒压充电，再以0.5C放电，此时的容量记为初始容量，电池容量首次衰减至初始容量80％(或小于初始容量80％)时对应的循环数记为容量衰减至80％时的循环数。
(4)能量密度测试：在25℃下，将制备得到的锂离子电池以0.2C倍率恒流恒压满充，以0.2C倍率满放，记录此时的放电容量，锂离子电池放电容量与锂离子电池体积的比值即为锂离子电池的体积能量密度。
需要说明的是，锂离子电池电压、内阻、循环寿命的测试属于本领域技术人员公知的技 术，在此不展开描述，并且测试方法不限于本申请描述的方法，还可以采用其他合适的测试方法。
<对比例2-7>
对比例2至对比例7与对比例1的区别在于，将负极活性材料中部分人造石墨替换为硅基材料Si-C，其中，对比例2中Si元素占负极活性材料的质量比例为1％，对比例3中Si元素占负极活性材料的质量比例为10％，对比例4中Si元素占负极活性材料的质量比例为20％，对比例5中Si元素占负极活性材料的质量比例为30％，对比例6中Si元素占负极活性材料的质量比例为60％，对比例7中Si元素占负极活性材料的质量比例为90％。
如下表1为对比例1至对比例7的能量密度测试结果和容量衰减到80％时循环次数的测试结果。
表1
Figure PCTCN2022084405-appb-000001
由上述表1可知，电化学装置的能量密度随着负极活性材料中Si含量的增加而增大，但电化学装置的循环寿命随着负极活性材料中Si含量的增加而明显衰减。
<对比例8-13>
对比例8至对比例13与对比例1的区别在于，将负极活性材料中部分人造石墨替换为硅基材料Si-C，使得Si元素占负极活性材料的质量比例为30％，对比例8的放电截止电压为2.3V，对比例9的放电截止电压为2.5V，对比例10的放电截止电压为2.8V，对比例11的放电截止电压为3.2V，对比例12的放电截止电压为3.4V，对比例13的放电截止电压为3.5V。对比例8至对比例13的充电截止电压与对比例5保持相同，为4.45V。
如下表2为对比例5和对比例8-13的能量密度测试结果和容量衰减到80％时循环次数的测试结果。
表2
Figure PCTCN2022084405-appb-000002
Figure PCTCN2022084405-appb-000003
由上述表2可知，电化学装置的能量密度随着放电截止电压的提高而减小，电化学装置的循环寿命随着放电截止电压的提高而明显改善。
<对比例14-17>
对比例14至对比例17与对比例1的区别在于，将负极活性材料中部分人造石墨替换为硅基材料Si-C，使得Si元素占负极活性材料的质量比例为30％，对比例14的充电截止电压为4.2V，对比例15的充电截止电压为4.3V，对比例16的充电截止电压为4.6V，对比例17的充电截止电压为4.9V。对比例14至对比例17的放电截止电压与对比例5保持相同，为3.0V。
如下表3为对比例5和对比例14-17的能量密度测试结果和容量衰减到80％时循环次数的测试结果。
表3
Figure PCTCN2022084405-appb-000004
由上述表3可知，电化学装置的能量密度随着充电截止电压的提高而增大，电化学装置的循环寿命随着充电截止电压的提高而衰减。
<实验例1-5>
实验例1至实验例5与对比例5的区别在于，将负极活性材料中部分人造石墨替换为硅基材料Si-C，使得Si元素占负极活性材料的质量比例为30％，充电截止电压保持4.45V，初始放电截止电压(第一放电截止电压)为3.0V，在电化学装置与壳体之间的压强达到相对应的第一阈值后，将放电截止电压提升0.2V，即将电化学装置的放电截止电压调整至第二放电截止电压(3.2V)，其中，实验例1对应的第一阈值为0.03MPa，实验例2对应的第一阈值为0.05MPa，实验例3对应的第一阈值为0.08MPa，实验例4对应的第一阈值为0.10MPa，实验例5对应的第一阈值为0.15MPa。
如下表4为对比例5和实验例1-5的放电截止电压提升时循环次数的测试结果和容量衰减到80％时循环次数的测试结果。
表4
Figure PCTCN2022084405-appb-000005
Figure PCTCN2022084405-appb-000006
在电化学装置与壳体之间的压强小于第一阈值时，说明电化学装置的不可逆膨胀较小，电化学装置的循环性能和对壳体的压力处于可控范围，可以按照初始放电截止电压进行充放电循环。由表4可知，如果第一阈值设置的较小(比如实验例1中的0.01MPa)，会使得电化学装置在循环50次时就提升放电截止电压，不利于充分利用电化学装置的能量密度。如果第一阈值设置的较大(比如实验例5中的0.15MPa)，会使得电化学装置在循环到400次时才抬高放电截止电压，对电化学装置的循环寿命的提升及不可逆膨胀的改善均相对受限，因为对于锂离子电池通常要求容量衰减至80％时的循环次数需要达到800次以上。
<实验例6-11>
实验例6与实验例3的区别在于，当电化学装置与壳体之间的压强达到第三阈值(0.5MPa)时，停止电化学装置的充放电循环，记录此时电化学装置的循环次数。
实验例7-11与实验例3的区别在于，增加第二阈值的设置，在电化学装置与壳体之间的压强达到第一阈值(0.08MPa)而没有达到相对应的第二阈值时，将第一放电截止电压(3.0V)提升至第二放电截止电压(3.2V)，当电化学装置与壳体之间的压强达到相对应的第二阈值后，将放电截止电压进一步提高0.2V，即将第二放电截止电压(3.2V)提升至第三放电截止电压(3.4V)，当电化学装置与壳体之间的压强达到第三阈值(0.5MPa)时，停止电化学装置的充放电循环，记录此时电化学装置的循环次数。其中，实验例7对应的第二阈值为0.10MPa，实验例8对应的第二阈值为0.15MPa，实验例9对应的第二阈值为0.20MPa，实验例10对应的第二阈值为0.25MPa，实验例11对应的第二阈值为0.30MPa。
如下表5为实验例3和实验例7-11的放电截止电压提升至第二放电截止电压时循环次数的测试结果、放电截止电压提升至第三放电截止电压时循环次数的测试结果、及电化学装置停止充放电时循环次数的测试结果。
表5
Figure PCTCN2022084405-appb-000007
由表5可知，根据实验例3，电化学装置在300次循环后，电化学装置与壳体之间的压强达到第一阈值。如实验例7-11，通过设定第二阈值，当电化学装置与壳体之间的压强达到第一阈值但未达到第二阈值时，将电化学装置的放电截止提升至第二放电截止电压(3.2V)， 直至电化学装置与壳体之间的压强达到第二阈值，将电化学装置的放电截止电压进一步提升至第三放电截止电压(3.4V)，即采用满充浅放的方式，可以提升电化学装置的循环寿命，降低电化学装置的不可逆体积膨胀，从而降低电化学装置对壳体的压力破坏。如果第二阈值设置得太小，会使得在电化学装置的循环状态较好时停止对电化学装置进行充放电操作或发出用于指示停止对电化学装置进行充放电操作的信息，缩短电化学装置的循环寿命。如果第二阈值设置得太大，会使得提升电化学装置的循环寿命和改善电化学装置的安全性能的作用相对受限。
<实验例12-16>
实验例12至实验例16与对比例5的区别在于，将负极活性材料中部分人造石墨替换为硅基材料Si-C，使得Si元素占负极活性材料的质量比例为30％，放电截止电压保持3.0V，初始充电截止电压(第一充电截止电压)为4.45V，在电化学装置与壳体之间的压强达到相对应的第一阈值后，将充电截止电压降低0.05V，即将电化学装置的充电截止电压调整至第二充电截止电压(4.4V)，其中，实验例12对应的第一阈值为0.01MPa，实验例13对应的第一阈值为0.05MPa，实验例14对应的第一阈值为0.08MPa，实验例15对应的第一阈值为0.10MPa，实验例16对应的第一阈值为0.15MPa。
如下表6为对比例5和实验例12-16的充电截止电压降低时循环次数的测试结果和容量衰减到80％时循环次数的测试结果。
表6
Figure PCTCN2022084405-appb-000008
在电化学装置与壳体之间的压强小于第一阈值时，说明电化学装置的不可逆膨胀较小，电化学装置的循环性能和对壳体的压力处于可控范围，可以按照初始充电截止电压进行充放电循环。由表6可知，如果第一阈值设置的较小(比如实验例12中的0.01MPa)，会使得电化学装置在循环50次时就降低充电截止电压，不利于充分利用电化学装置的能量密度。如果第一阈值设置的较大(比如实验例16中的0.15MPa)，会使得电化学装置在循环到400次时才降低充电截止电压，对电化学装置的循环寿命及不可逆膨胀的改善均相对受限，因为对于锂离子电池通常要求容量衰减的到80％时的循环次数需要达到800次以上。
<实验例17-22>
实验例17与实验例14的区别在于，当电化学装置与壳体之间的压强达到第三阈值(0.5MPa)时，停止电化学装置的充放电循环，记录此时电化学装置的循环次数。
实验例18-22与实验例14的区别在于，增加第二阈值的设置，在电化学装置与壳体之间 的压强达到第一阈值(0.08MPa)而没有达到相对应的第二阈值时，将第一充电截止电压(4.45V)降低至第二充电截止电压(4.4V)，当电化学装置与壳体之间的压强达到相对应的第二阈值后，将充电截止电压进一步降低0.05V，即将第二充电截止电压(4.5V)降低至第三充电截止电压(4.35V)，当电化学装置与壳体之间的压强达到第三阈值(0.5MPa)时，停止电化学装置的充放电循环，记录此时电化学装置的循环次数。其中，实验例18对应的第二阈值为0.10MPa，实验例19对应的第二阈值为0.15MPa，实验例20对应的第二阈值为0.20MPa，实验例21对应的第二阈值为0.25MPa，实验例22对应的第二阈值为0.30MPa。
如下表7为实验例14和实验例17-22的充电截止电压降低至第二充电截止电压时循环次数的测试结果、充电截止电压降低至第三放电截止电压时循环次数的测试结果、及电化学装置停止充放电时循环次数的测试结果。
表7
Figure PCTCN2022084405-appb-000009
由表7可知，根据实验例14，电化学装置在300次循环后，电化学装置与壳体之间的压强达到第一阈值。如实验例18-22，通过设定第二阈值，当电化学装置与壳体之间的压强达到第一阈值但未达到第二阈值时，将将电化学装置的充电截止电压降低至第二充电截止电压(4.4V)，直至电化学装置与壳体之间的压强达到第二阈值，将电化学装置的充电截止电压进一步降低至第三充电截止电压(4.35V)，即采用浅充的方式，可以提升电化学装置的循环寿命，降低电化学装置的不可逆体积膨胀，从而降低电化学装置对壳体的压力破坏。
<实验例23-26>
实验例23-26与实验例21的区别在于，第一放电截止电压为3.0V，第一充电截止电压为4.45V，第一阈值为0.08MPa，第二阈值为0.25MPa，第三阈值为0.5MPa。当电化学装置与壳体之间的压强达到第一阈值但为到达第二阈值时，将第一放电截止电压(3.0V)提升相对应的第一预设值至第二放电截止电压，并将第一充电截止电压(4.45V)降低相对应的第二预设值至第二充电截止电压。当电化学装置与壳体之间的压强达到第二阈值时，将第二放电截止电压提升相对应的第一预设值至第三放电截止电压，并将第二充电截止电压降低相对应的第二预设值至第三放电截止电压。实验例21对应的第一预设值为0，对应的第二预设值为0.05V。实验例23对应的第一预设值为0.1V，对应的第二预设值为0.05V。实验例24对应的第一预设值为0.2V，对应的第二预设值为0。实验例25对应的第一预设值为0.2V，对应的第二预 设值为0.025V。实验例26对应的第一预设值为0.2V，对应的第二预设值为0.05V。
如下表8为实验例21和实验例23-26的电化学装置停止充放电时循环次数的测试结果。
表8
Figure PCTCN2022084405-appb-000010
在电化学装置与壳体之间的压强达到第一阈值或第二阈值后，需要提升放电截止电压和降低充电截止电压，需要平衡第一预设值和第二预设值的比例，通常需要第一预设值大于第二预设值。
应该理解，本说明书中的各个实施例均采用递进的方式描述，各个实施例之间相同或相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于方法实施例而言，由于其基本相似于装置和系统实施例中描述的方法，所以描述的比较简单，相关之处参见其他实施例的部分说明即可。
应该理解，上述对本说明书特定实施例进行了描述。其它实施例在权利要求书的范围内。在一些情况下，在权利要求书中记载的动作或步骤可以按照不同于实施例中的顺序来执行并且仍然可以实现期望的结果。另外，在附图中描绘的过程不一定要求示出的特定顺序或者连续顺序才能实现期望的结果。在某些实施方式中，多任务处理和并行处理也是可以的或者可能是有利的。
应该理解，本文用单数形式描述或者在附图中仅显示一个的元件并不代表将该元件的数量限于一个。此外，本文中被描述或示出为分开的模块或元件可被组合为单个模块或元件，且本文中被描述或示出为单个的模块或元件可被拆分为多个模块或元件。
还应理解，本文采用的术语和表述方式只是用于描述，本说明书的一个或多个实施例并不应局限于这些术语和表述。使用这些术语和表述并不意味着排除任何示意和描述(或其中部分)的等效特征，应认识到可能存在的各种修改也应包含在权利要求范围内。其他修改、变化和替换也可能存在。相应的，权利要求应视为覆盖所有这些等效物。

Claims (22)

  1. 一种电化学装置，其特征在于：
    所述电化学装置的负极活性材料包括第一活性材料和第二活性材料；
    所述第一活性材料的克容量小于所述第二活性材料；
    所述第一活性材料的放电工作电压范围包括不大于所述第二活性材料的放电工作电压上限的第一电压范围；
    所述电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行；
    所述电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行；
    所述第一放电截止电压和所述第二放电截止电压均位于所述第一电压范围内；其中，
    所述第一放电截止电压小于所述第二放电截止电压，和/或，所述第一充电截止电压大于所述第二充电截止电压。
  2. 根据权利要求1所述的电化学装置，其中，
    所述第一活性材料的放电工作电压范围进一步包括大于所述第二活性材料的放电工作电压上限的第二电压范围；
    所述电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行；其中，
    所述第三放电截止电压位于所述第二电压范围，和/或，所述第二充电截止电压大于所述第三充电截止电压。
  3. 根据权利要求2所述的电化学装置，其中，所述第二活性材料包括硅，所述第一电压范围为不大于3.5V，所述第二电压范围为大于3.5V。
  4. 根据权利要求2所述的电化学装置，其中，所述电化学装置在第四时间段执行如下操作中的至少一个：
    (i)停止进行充放电；
    (ii)发出用于指示停止对所述电化学装置进行充放电操作的信息。
  5. 根据权利要求4所述的电化学装置，其中，所述第一时间段、所述第二时间段、所述第三时间段和所述第四时间段按时间顺序依次排列。
  6. 根据权利要求5所述的电化学装置，其中，所述电化学装置在不同的时间段运行时，所述电化学装置的健康状态参数位于不同的取值范围。
  7. 根据权利要求6所述的电化学装置，其中，所述健康状态参数包括如下各项中的至少一个：
    (i)所述电化学装置的内阻；
    (ii)所述电化学装置的可逆容量；
    (iii)所述电化学装置的厚度；
    (iiii)所述电化学装置与用于装容所述电化学装置的壳体之间的压力或压强。
  8. 根据权利要求7所述的电化学装置，其中，所述健康状态参数为所述电化学装置与所述壳体之间的压强；
    当所述电化学装置与所述壳体之间的压强小于第一阈值时，所述电化学装置在所述第一时间段运行；
    当所述电化学装置与所述壳体之间的压强大于或等于所述第一阈值且小于第二阈值时，所述电化学装置在所述第二时间段运行；
    当所述电化学装置与所述壳体之间的压强大于或等于所述第二阈值且小于第三阈值时，所述电化学装置在所述第三时间段运行；
    当所述电化学装置与所述壳体之间的压强大于或等于所述第三阈值时，所述电化学装置在所述第四时间段运行。
  9. 根据权利要求8所述的电化学装置，其中，所述第一阈值大于或等于0.03MPa，所述第二阈值小于0.5MPa，所述第三阈值大于或等于0.5MPa，所述第二阈值大于所述第一阈值。
  10. 根据权利要求1-9中任一项所述的电化学装置，其中，所述第二活性材料包括硅，所述负极活性材料中硅的质量占比位于(0％,60％]范围内。
  11. 根据权利要求10所述的电化学装置，其中，所述负极活性材料中硅的质量占比位于[10％,30％]范围内。
  12. 一种电化学装置控制方法，用于对电化学装置的充放电过程进行控制，所述电化学装置的负极活性材料包括第一活性材料和第二活性材料，所述第一活性材料的克容量小于所述第二活性材料，所述第一活性材料的放电工作电压范围包括不大于所述第二活性材料的放电工作电压上限的第一电压范围，所述电化学装置控制方法包括：
    控制所述电化学装置在第一时间段以第一放电截止电压和第一充电截止电压运行，所述第一放电截止电压位于所述第一电压范围内；
    控制所述电化学装置在第二时间段以第二放电截止电压和第二充电截止电压运行，所述第二放电截止电压位于所述第一电压范围内；
    其中，所述第一放电截止电压小于所述第二放电截止电压，和/或，所述第一充电截止电压大于所述第二充电截止电压。
  13. 根据权利要求12所述的电化学装置控制方法，其中，所述第一活性材料的放电工作电压范围包括大于所述第二活性材料的放电工作电压上限的第二电压范围，所述电化学装置控制方法还包括：
    控制所述电化学装置在第三时间段以第三放电截止电压和第三充电截止电压运行；
    其中，所述第三放电截止电压位于所述第二电压范围，和/或，所述第二充电截止电压大于所述第三充电截止电压。
  14. 根据权利要求13所述的电化学装置控制方法，其中，所述电化学装置控制方法还包括：
    在第四时间段控制所述电化学装置执行如下操作中的至少一个：
    (i)停止进行充放电；
    (ii)发出用于指示停止对所述电化学装置进行充放电操作的信息。
  15. 根据权利要求14所述的电化学装置控制方法，其中，所述第一时间段、所述第二时间段、所述第三时间段和所述第四时间段在所述电化学装置的生命周期中按时间顺序依次排列。
  16. 根据权利要求15所述的电化学装置控制方法，其中，所述电化学装置控制方法还包 括：
    根据所述电化学装置的健康状态参数所处的取值范围，确定所述电化学装置所在的时间段。
  17. 根据权利要求16所述的电化学装置控制方法，其中，所述健康状态参数包括如下各项中的至少一个：
    (i)所述电化学装置的内阻；
    (ii)所述电化学装置的可逆容量；
    (iii)所述电化学装置的厚度；
    (iiii)所述电化学装置与用于装容所述电化学装置的壳体之间的压力或压强。
  18. 根据权利要求12-17中任一项所述的电化学装置控制方法，其中，所述第二活性材料包括硅，所述负极活性材料中硅的质量占比位于(0％,60％]范围内。
  19. 根据权利要求18所述的电化学装置控制方法，其中，所述负极活性材料中硅的质量占比位于[10％,30％]范围内。
  20. 一种电化学装置管理系统，所述电化学装置管理系统与电化学装置连接，所述电化学装置管理系统用于执行如权利要求12-19中任一项所述的电化学装置控制方法。
  21. 一种电子设备，包括如权利要求1-11中任一项所述的电化学装置或如权利要求20所述的电化学装置管理系统。
  22. 一种计算机可读存储介质，所述计算机可读存储介质上存储有计算机程序，所述计算机程序被处理器执行时实现如权利要求12-19中任一项所述的电化学装置控制方法。
PCT/CN2022/084405 2022-03-31 2022-03-31 电化学装置及其控制方法、电子设备和存储介质 WO2023184336A1 (zh)

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