Electrochemical device management method, system, electronic device, and charging device

Abstract

This application provides an electrochemical device management method, system, electronic device, and charging device, including: performing a first charge-discharge cycle on the electrochemical device with a charging current; performing an intermittent charging operation on the electrochemical device with a detection current, acquiring data related to the electrochemical device during the intermittent charging operation, and determining the lithium plating state of charge (SBC) of the electrochemical device based on the data related to the electrochemical device; performing a second charge-discharge cycle on the electrochemical device with a charging current in response to the SBC of the electrochemical device being greater than a SBC threshold; or performing a second charge-discharge cycle on the electrochemical device with a target charging current in response to the SBC of the electrochemical device being less than or equal to the SBC threshold. This application can reduce the charging current of the electrochemical device to reduce the risk of lithium plating and improve the safety of the electrochemical device.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, specifically to an electrochemical device management method, system, electronic device, and charging device. Background Technology

[0002] Lithium-ion batteries have many advantages, such as high specific energy density and long cycle life, and are widely used in the consumer electronics field.

[0003] Lithium-ion batteries may experience lithium plating during use. When a risk of lithium plating is detected, timely measures should be taken to reduce this risk in order to ensure battery safety. Summary of the Invention

[0004] The purpose of this application is to provide a method, system, electronic device, and charging device for managing electrochemical devices, thereby reducing the risk of lithium plating during use and improving the safety of electrochemical devices. The specific technical solution is as follows:

[0005] A first aspect of this application provides an electrochemical device management method, comprising: i) performing a first charge-discharge cycle on the electrochemical device with a charging current; ii) performing an intermittent charging operation on the electrochemical device with a detection current, acquiring data related to the electrochemical device during the intermittent charging operation, and determining the lithium plating state of charge of the electrochemical device based on the data related to the electrochemical device; iii-1 performing a second charge-discharge cycle on the electrochemical device with the charging current in response to the lithium plating state of charge of the electrochemical device being greater than a state of charge threshold; or iii-2 performing a second charge-discharge cycle on the electrochemical device with a target charging current in response to the lithium plating state of charge of the electrochemical device being less than or equal to the state of charge threshold, wherein the target charging current is less than the charging current.

[0006] The technical effects of the embodiments of this application are as follows: Based on the data related to the electrochemical device obtained during intermittent charging operation, the lithium plating state of the electrochemical device is determined. In response to the lithium plating state of the electrochemical device being less than or equal to the state of charge threshold, the electrochemical device is charged with a smaller charging current, i.e., the target charging current. This can reduce the charging current of the electrochemical device to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0007] In one embodiment of this application, the electrochemical device management method further includes repeating step ii and steps iii-1 or iii-2 after step iii-1; or repeating step ii and steps iii-1 or iii-2 after step iii-2. In this embodiment, in step iii-1, since the electrochemical device can be subjected to a second charge-discharge cycle with the charging current, the service life of the electrochemical device is extended; in step iii-2, since the electrochemical device can be subjected to a second charge-discharge cycle with a target charging current smaller than the charging current, the risk of lithium plating occurring due to the electrochemical device continuing to operate at the original large charging current is reduced.

[0008] In one embodiment of this application, the data related to the electrochemical device includes the state of charge (SOC) and internal resistance of the electrochemical device. The intermittent charging operation includes multiple charging periods and multiple interrupted periods. The step of acquiring the data related to the electrochemical device during the intermittent charging operation and determining the lithium plating SOC of the electrochemical device based on the data related to the electrochemical device includes, during the intermittent charging operation, acquiring the SOC and internal resistance of the electrochemical device for each of the multiple interrupted periods; obtaining a first curve based on the acquired multiple SOCs and the multiple internal resistances of the electrochemical device corresponding to the multiple SOCs, wherein the first curve is a mapping curve corresponding to the SOC and internal resistance of the electrochemical device; and determining the lithium plating SOC of the electrochemical device based on the first curve.

[0009] In one embodiment of this application, the step of determining the lithium plating state of charge of the electrochemical device based on the first curve includes at least one of method 1 or method 2, wherein: method 1 includes: performing a first-order derivative on the first curve to obtain a second curve; and determining the state of charge corresponding to the first point on the second curve with a negative slope as the lithium plating state of charge; method 2 includes: performing a first-order derivative on the first curve to obtain a second curve; performing a second-order derivative on the second curve to obtain a third curve; and determining the state of charge corresponding to the first point on the third curve with a ordinate less than zero as the lithium plating state of charge.

[0010] In one embodiment of this application, the method further includes: determining the target charging current based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, wherein the charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current. This embodiment of the application determines the target charging current through the charging current-lithium plating state of charge mapping relationship, which can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0011] In one embodiment of this application, the step of determining the target charging current based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship includes: determining the charging current value in the mapping relationship that is closest to the charging current as the target charging current; or determining the lithium plating state of charge in the mapping relationship that is greater than the state of charge threshold and has the smallest difference from the state of charge threshold as the target lithium plating state of charge, and determining the charging current corresponding to the target lithium plating state of charge as the target charging current. This embodiment of the application determines the target charging current through the charging current-lithium plating state of charge mapping relationship, which can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0012] In one embodiment of this application, the method further includes: determining the target charging current based on at least one of the charging current or the state of charge threshold, the current ambient temperature, and a pre-established temperature-charging current-lithium plating state of charge mapping relationship, wherein the temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, the charging current, and at least one lithium plating state of charge corresponding to the at least one charging current. This embodiment of the application can reduce the charging current of the electrochemical device to a target charging current for electrochemical devices operating at different ambient temperatures, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device operating at different ambient temperatures.

[0013] In one embodiment of this application, the step of determining the target charging current based on at least one of the charging current or the state of charge threshold, the current ambient temperature, and a pre-established charging current-lithium plating state of charge mapping relationship includes, at the current ambient temperature, determining the charging current value in the mapping relationship that is closest to the charging current as the target charging current; or, at the current ambient temperature, determining the lithium plating state of charge in the mapping relationship that is greater than the state of charge threshold and has the smallest difference from the state of charge threshold as the target lithium plating state of charge, and determining the charging current corresponding to the target lithium plating state of charge as the target charging current. This embodiment of the application can reduce the charging current of electrochemical devices to a target charging current to reduce the risk of lithium plating and improve the safety of electrochemical devices operating under different ambient temperatures.

[0014] In one embodiment of this application, the step of intermittently charging the electrochemical device includes multiple charging cycles, each charging cycle comprising a charging period and an intermittent period, wherein during each charging period, the state of charge of the electrochemical device increases by a unit magnitude. Embodiments of this application can determine the lithium plating state of charge of the electrochemical device based on intermittent charging operations, reducing the risk of lithium plating in the electrochemical device.

[0015] In one embodiment of this application, the electrochemical device includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, or lithium cobalt oxide. Specifically, the electrochemical device includes lithium iron phosphate, with the unit amplitude ranging from 0.5% to 10% and the duration of the intermittent period ranging from 1 second to 15 seconds; the electrochemical device includes lithium nickel cobalt manganese oxide, with the unit amplitude ranging from 0.5% to 10% and the duration of the intermittent period ranging from 1 second to 30 seconds; and the electrochemical device includes lithium cobalt oxide, with the unit amplitude ranging from 0.5% to 10% and the duration of the intermittent period ranging from 1 second to 30 seconds. This embodiment of the application more specifically performs intermittent charging operations on electrochemical devices of different systems, enabling more accurate determination of the lithium plating state of charge of the electrochemical devices of different systems.

[0016] In one embodiment of this application, the method satisfies at least one of conditions a) to f): a) the electrochemical device comprises lithium iron phosphate, the electrochemical device is located at an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption period ranges from 5 seconds to 15 seconds; b) the electrochemical device comprises lithium iron phosphate, the electrochemical device is located at an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption period ranges from 1 second to 10 seconds; c) the electrochemical device comprises lithium nickel cobalt manganese oxide, the electrochemical device is located at an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the... The duration of the intermittent period ranges from 10 to 30 seconds; d) the electrochemical device includes lithium nickel cobalt manganese oxide, the electrochemical device is in an ambient temperature range of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 to 10 seconds; e) the electrochemical device includes lithium cobalt oxide, the electrochemical device is in an ambient temperature range of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 15 to 30 seconds; f) the electrochemical device includes lithium cobalt oxide, the electrochemical device is in an ambient temperature range of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 to 10 seconds. The embodiments of this application more specifically perform intermittent charging operations on electrochemical devices in different temperature environments, and can more accurately obtain the lithium plating state of charge of electrochemical devices in different systems.

[0017] A second aspect of this application provides a computer-readable storage medium, wherein a computer program is stored therein, and when executed by a processor, the computer program implements the steps of the method described in any of the above aspects.

[0018] A third aspect of this application provides a charging device, including a processor and a machine-readable storage medium, wherein the machine-readable storage medium stores machine-executable instructions that can be executed by the processor, and when the processor executes the machine-executable instructions, it implements the steps of the method described in any of the above aspects.

[0019] A fourth aspect of this application provides an electrochemical device including a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, wherein the processor, when executing the machine-executable instructions, implements the steps of the method described in any of the above aspects.

[0020] A fifth aspect of this application provides an electronic device, which includes the electrochemical device described in the fourth aspect.

[0021] A sixth aspect of this application provides a system comprising: a charge-discharge device and a state of charge (SCC) analysis device, wherein the charge-discharge device is configured to perform a first charge-discharge cycle on an electrochemical device using a charging current; the SCC analysis device is configured to perform an intermittent charging operation on the electrochemical device using a detection current, acquire data related to the electrochemical device during the intermittent charging operation, and determine the lithium plating SCC of the electrochemical device based on the data related to the electrochemical device; the charge-discharge device is further configured to perform a second charge-discharge cycle on the electrochemical device using the charging current in response to the lithium plating SCC of the electrochemical device being greater than a SCC threshold; or to perform a second charge-discharge cycle on the electrochemical device using a target charging current in response to the lithium plating SCC of the electrochemical device being less than or equal to the SCC threshold, wherein the target charging current is less than the charging current. Embodiments of this application can reduce the charging current of the electrochemical device to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0022] In one embodiment of this application, the data related to the electrochemical device includes the state of charge (SOC) and internal resistance of the electrochemical device. The intermittent charging operation includes multiple charging periods and multiple interruptions. Specifically, the SOC analysis device is used, during the intermittent charging operation, to acquire the SOC and internal resistance of the electrochemical device for each of the multiple interruptions during that interruption. Based on the acquired multiple SOCs and the corresponding internal resistances, a first curve is obtained, which is a mapping curve corresponding to the SOC and internal resistance of the electrochemical device. Based on the first curve, the lithium plating SOC of the electrochemical device is determined. This embodiment of the application reduces the risk of lithium plating occurring in the electrochemical device due to continued operation at the original large charging current.

[0023] In one embodiment of this application, the state of charge analysis device is specifically used to perform a first-order derivative on the first curve to obtain a second curve; and to determine the state of charge corresponding to the first point on the second curve where the slope is negative as the lithium plating state of charge; or to perform a first-order derivative on the first curve to obtain a second curve; and to perform a second-order derivative on the second curve to obtain a third curve; and to determine the state of charge corresponding to the first point on the third curve where the ordinate is less than zero as the lithium plating state of charge.

[0024] In one embodiment of this application, the charging and discharging device is further configured to: determine the target charging current based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, wherein the charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current. This embodiment of the application determines the target charging current through the charging current-lithium plating state of charge mapping relationship, which can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0025] In one embodiment of this application, the charging and discharging device is specifically used to determine the charging current value closest to the charging current in the mapping relationship as the target charging current; or to determine the lithium plating state of charge (PPC) value in the mapping relationship that is greater than the PCC threshold and has the smallest difference from the PCC threshold as the target PCC value, and to determine the charging current corresponding to the target PCC value as the target charging current. This embodiment of the application determines the target charging current through the charging current-lithium plating PCC mapping relationship, which can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0026] In one embodiment of this application, the charging and discharging device is further configured to determine the target charging current based on at least one of the charging current or the state of charge threshold, the current ambient temperature, and a pre-established temperature-charging current-lithium plating state of charge mapping relationship. The temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, the charging current, and at least one lithium plating state of charge corresponding to the at least one charging current. This embodiment of the application can reduce the charging current of the electrochemical device to a target charging current for electrochemical devices operating at different ambient temperatures, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device operating under different ambient temperatures.

[0027] In one embodiment of this application, the charging and discharging device is specifically used to determine, at the current ambient temperature, the charging current value closest to the charging current in the mapping relationship that is the target charging current; or, at the current ambient temperature, to determine, at the current ambient temperature, the lithium plating state of charge in the mapping relationship that is greater than the state of charge threshold and has the smallest difference from the state of charge threshold that is the target lithium plating state of charge, and to determine the charging current corresponding to the target lithium plating state of charge as the target charging current. This embodiment of the application can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device operating at different ambient temperatures.

[0028] In one embodiment of this application, the intermittent charging operation includes multiple charging cycles, each charging cycle comprising a charging period and an intermittent period, during which the state of charge of the electrochemical device increases by a unit magnitude. Embodiments of this application can determine the lithium plating state of charge of the electrochemical device based on the intermittent charging operation, reducing the risk of lithium plating in the electrochemical device.

[0029] In one embodiment of this application, the electrochemical device includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, or lithium cobalt oxide. Specifically, the state of charge analysis device is used when the electrochemical device includes lithium iron phosphate, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 15 seconds; the electrochemical device includes lithium nickel cobalt manganese oxide, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds; and the electrochemical device includes lithium cobalt oxide, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds. This embodiment of the application more specifically performs intermittent charging operations on electrochemical devices of different systems, enabling more accurate determination of the lithium plating state of charge of electrochemical devices of different systems.

[0030] In one embodiment of this application, the state of charge analysis device is specifically used for at least one of the following a) to f): a) the electrochemical device comprises lithium iron phosphate, the electrochemical device is located at an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption period ranges from 5 seconds to 15 seconds; b) the electrochemical device comprises lithium iron phosphate, the electrochemical device is located at an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption period ranges from 1 second to 10 seconds; c) the electrochemical device comprises lithium nickel cobalt manganese oxide, the electrochemical device is located at an ambient temperature of -10°C to 10°C, and the unit amplitude ranges from 0.5% to 10%. d) The electrochemical device comprises lithium nickel cobalt manganese oxide, the electrochemical device is located at an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds; e) The electrochemical device comprises lithium cobalt oxide, the electrochemical device is located at an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 15 seconds to 30 seconds; f) The electrochemical device comprises lithium cobalt oxide, the electrochemical device is located at an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds. The embodiments of this application more specifically perform intermittent charging operations on electrochemical devices in different temperature environments, and can more accurately obtain the lithium plating state of charge of electrochemical devices in different systems.

[0031] This application provides an electrochemical device management method, system, electronic device, and charging device. Based on data related to the electrochemical device acquired during intermittent charging operations, it determines the lithium plating state of charge (SBC) of the electrochemical device. In response to the SBC being less than or equal to a threshold value, the electrochemical device is charged with a smaller charging current (target charging current). This reduces the charging current of the electrochemical device, thereby lowering the risk of lithium plating and improving its safety. Of course, implementing any product or method of this application does not necessarily require achieving all of the above advantages simultaneously. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of this application and the prior art, the accompanying drawings used in the embodiments and the prior art are briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0033] Figure 1 This is a flowchart illustrating an electrochemical device management method according to one embodiment of this application;

[0034] Figure 2 This is a schematic diagram of the first curve of one embodiment of this application;

[0035] Figure 3 This is a schematic diagram of the second curve according to one embodiment of this application;

[0036] Figure 4 This is a schematic diagram of the system structure according to one embodiment of this application;

[0037] Figure 5 This is a schematic diagram of the structure of a charging device according to one embodiment of this application;

[0038] Figure 6 This is a schematic diagram of another system structure according to one embodiment of this application. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other technical solutions obtained by those skilled in the art based on the embodiments of this application fall within the scope of protection of this application.

[0040] It should be noted that, in the specific embodiments of this application, lithium-ion batteries are used as an example of electrochemical devices to explain this application, but the electrochemical devices of this application are not limited to lithium-ion batteries.

[0041] This application provides a method for managing an electrochemical device, such as... Figure 1 As shown, the method includes the following steps:

[0042] Step i: Perform the first charge-discharge cycle on the electrochemical device using the charging current;

[0043] The implementing entity in this application embodiment can be a battery management system. During the operation of the electrochemical device, the battery management system can manage the electrochemical device, such as managing the charging and discharging processes of the electrochemical device.

[0044] In this embodiment, the battery management system can control the charging current during the charge-discharge cycle of the electrochemical device. For example, during the operation of the electrochemical device, the charge-discharge device 401 in the battery management system uses a charging current to perform charge-discharge cycles on the electrochemical device. The charge-discharge cycle in this embodiment can refer to the cyclic process of charging, discharging, and charging the electrochemical device during operation. In the first charge-discharge cycle, the aforementioned charging current can be used to charge the electrochemical device during the charging phase. Furthermore, the discharge current in the charge-discharge cycle can be adapted to the electrical equipment; this embodiment does not limit this.

[0045] The embodiments of this application do not impose any particular limitation on the structure of the charging and discharging device. For example, it may include a charging and discharging circuit within the field of technology. This application does not limit this. Exemplarily, the above-mentioned charging and discharging circuit may be... Figure 5 The charging and discharging circuit 504 shown is described. The charging current in this embodiment is not particularly limited, and can be any current between 0.1A and 3A, such as 0.1A, 0.2A, 0.3A, 0.5A, 0.7A, 1A, 1.5A, 2A, 2.5A or 3A.

[0046] Step ii: Perform intermittent charging operation on the electrochemical device with the detection current, acquire data related to the electrochemical device during the intermittent charging operation, and determine the lithium plating state of the electrochemical device based on the data related to the electrochemical device.

[0047] In this application, intermittent charging operation can refer to the process of intermittently charging an electrochemical device. In one embodiment of this application, the intermittent charging operation includes multiple charging periods and multiple interruption periods.

[0048] The state of charge (SOC) of lithium plating can refer to the state of charge associated with the lithium plating state of an electrochemical device. For example, the SOC analysis device 402 in a battery management system can perform intermittent charging operations on the electrochemical device. This application embodiment does not impose any particular limitation on the SOC analysis device, as long as it can implement intermittent charging operations. The SOC analysis device 402 may include, for example, a microcontroller unit (MCU) in a battery management system (BMS). In one example, after the charging and discharging device 401 performs a first charge-discharge cycle on the electrochemical device, the SOC analysis device 402, in response to the first charge-discharge cycle reaching the aforementioned first cycle number, detects the current and performs intermittent charging operations on the electrochemical device. During the intermittent charging operation, it performs lithium plating detection and analysis on the electrochemical device, acquires data related to the electrochemical device during the intermittent charging operation, and determines the lithium plating SOC of the electrochemical device based on the data related to the electrochemical device. The state of charge can be denoted as SOC (State of Charge). The operation of the process described above is for illustrative purposes only.

[0049] Data related to electrochemical devices can refer to data that reflects the state of the electrochemical device, including but not limited to data such as charging voltage, charging current, internal resistance, and state of charge.

[0050] This application does not impose any particular restrictions on the charging method in the intermittent charging operation. As long as the purpose of this application embodiment can be achieved, it can be constant voltage charging, constant current charging, constant current and constant voltage charging, or segmented constant current charging.

[0051] Step iii-1: In response to the lithium plating state of the electrochemical device being greater than the state of charge threshold, perform a second charge-discharge cycle on the electrochemical device with the charging current;

[0052] For example, the state of charge (SCC) analyzer 402 performs intermittent charging of the electrochemical device. During the intermittent charging operation, it performs lithium plating detection and analysis on the electrochemical device. If the lithium plating SCC of the electrochemical device is greater than the SCC threshold, it sends a first signal to the charge / discharge device 401. After receiving the first signal, the charge / discharge device 401 performs a second charge / discharge cycle on the electrochemical device with the charging current. The number of cycles in the second charge / discharge cycle can be less than or equal to the number of cycles in the first charge / discharge cycle. This is because as the electrochemical device continues to cycle, its lithium plating window gradually narrows, i.e., it becomes easier to plating lithium. Therefore, the number of cycles in the second charge / discharge cycle is set to be less than the number of cycles in the first charge / discharge cycle so that lithium plating detection and analysis can be performed on the electrochemical device again after the second charge / discharge cycle. In the embodiments of this application, for example, the number of cycles in the first charge / discharge cycle can be from 1 to 500, and the number of cycles in the second charge / discharge cycle can be from 1 to 100. The operation of the above-described process is for illustrative purposes only. In addition, the devices and modules in the battery management system examples in the embodiments of this application are for illustrative purposes only and are not restrictive.

[0053] The embodiments of this application can acquire data related to the electrochemical device during intermittent charging operations, and determine the lithium plating state of the electrochemical device based on this data, which facilitates subsequent protection measures for the electrochemical device.

[0054] The state of charge (SOC) of lithium plating can refer to the SOC associated with the lithium plating state of an electrochemical device. The SOC threshold can be a pre-set threshold. The SOC threshold can be pre-stored in a storage medium connected to the electrochemical device. The SOC threshold is generally set based on the SOC corresponding to lithium plating in an electrochemical device sample of the same system. For example, the SOC threshold can be set to the SOC corresponding to lithium plating in an electrochemical device sample. Different SOC thresholds are typically set for different electrochemical device systems. For the same electrochemical device sample, the SOC corresponding to lithium plating will differ at different charging rates and / or ambient temperatures. In some embodiments, a charging current-lithium plating SOC mapping relationship, or a temperature-charging current-lithium plating SOC mapping relationship, can be pre-set and stored in a storage medium connected to the electrochemical device.

[0055] When the state of charge of lithium plating in the electrochemical device is greater than the state of charge threshold, it indicates that lithium plating has not yet occurred and the device can continue to operate. Based on this, the embodiments of this application can perform a second charge-discharge cycle on the electrochemical device with the charging current, so that the electrochemical device can continue to operate, thus improving the problem of "false death" of the electrochemical device being abandoned before reaching its lifespan.

[0056] Step iii-2: In response to the lithium plating state of charge of the electrochemical device being less than or equal to the state of charge threshold, perform a second charge-discharge cycle on the electrochemical device with the target charging current.

[0057] For example, the state of charge (SCC) analyzer 402 performs intermittent charging of the electrochemical device, and performs lithium plating detection and analysis on the electrochemical device during the intermittent charging operation. If the lithium plating SCC of the electrochemical device is less than or equal to the SCC threshold, a second signal is sent to the charge / discharge device 401. After receiving the second signal, the charge / discharge device 401 performs a second charge / discharge cycle on the electrochemical device with a target charging current, wherein the target charging current is less than the charging current. The above-described process is for illustrative purposes only. Furthermore, the devices and modules in the battery management system examples provided in this application are for illustrative purposes only and are not restrictive.

[0058] This application embodiment can reduce the charging current of an electrochemical device when the lithium plating state of charge (SPC) is less than or equal to the SPC threshold. Generally, if the SPC of an electrochemical device is less than or equal to the SPC threshold, it indicates that the electrochemical device is prone to lithium plating or has already plating. In this case, by reducing the charging current of the electrochemical device, the risk of lithium plating due to continued operation at the original high charging current can be reduced, thereby improving the safety of the electrochemical device.

[0059] In one embodiment of this application, after step iii-1, step ii and steps iii-1 or iii-2 are repeated.

[0060] In this embodiment of the application, after performing a second charge-discharge cycle on the electrochemical device with the charging current in response to the lithium plating state of charge (SPC) of the electrochemical device being greater than the SPC threshold (i.e., after step iii-1), the electrochemical device can be intermittently charged again. During this intermittent charging operation, data related to the electrochemical device is acquired. Based on this data, the SPC of the electrochemical device is determined, thereby assessing the relationship between the SPC and the SPC threshold, and then either step iii-1 or iii-2 is executed. In step iii-1, since a second charge-discharge cycle can be performed on the electrochemical device with the charging current, the lifespan of the electrochemical device is extended. In step iii-2, since a second charge-discharge cycle can be performed on the electrochemical device with a charging current less than the target charging current, the risk of lithium plating occurring due to continued operation at the original large charging current is reduced.

[0061] In one embodiment of this application, after step iii-2, step ii and steps iii-1 or iii-2 are repeated.

[0062] In this embodiment, after performing a second charge-discharge cycle on the electrochemical device with a target charging current in response to the lithium plating state of charge (SPC) being less than or equal to the SPC threshold (i.e., after step iii-2), the electrochemical device can be intermittently charged again. During this intermittent charging, data related to the electrochemical device is acquired, and the SPC of the electrochemical device is determined based on this data. This allows for a determination of the relationship between the SPC and the SPC threshold, leading to the execution of either step iii-1 or step iii-2. In step iii-1, the second charge-discharge cycle with the charging current extends the lifespan of the electrochemical device. In step iii-2, the second charge-discharge cycle with a target charging current less than the charging current reduces the risk of lithium plating due to continued operation at the original high charging current.

[0063] Intermittent charging operation can refer to the process of intermittently charging an electrochemical device. In one embodiment of this application, the intermittent charging operation includes multiple charging periods and multiple interruptions, and the lithium-plating state of charge of the electrochemical device is determined in the following manner:

[0064] Step A: During the intermittent charging operation, for each of the multiple intermittent periods, obtain the state of charge and internal resistance of the electrochemical device during that intermittent period.

[0065] Step B: Based on the multiple states of charge of the electrochemical device and the multiple internal resistances of the electrochemical device corresponding to the multiple states of charge, the first curve is obtained;

[0066] In this embodiment, after obtaining the state of charge and internal resistance during multiple intermittent periods of the electrochemical device, multiple data pairs consisting of the state of charge and internal resistance can be obtained. (Reference) Figure 2 The state of charge of the electrochemical device can be used as the abscissa and the internal resistance of the electrochemical device as the ordinate. The points represented by these data pairs can be filled into the coordinate system, and after fitting, the first curve is obtained. The first curve represents the mapping curve between the state of charge and the internal resistance of the electrochemical device.

[0067] It is understandable that the more intensive the acquisition of state of charge and internal resistance data of the electrochemical device, the more data pairs are obtained, resulting in a more detailed first curve. The process of curve fitting using data is well known to those skilled in the art, and the comparison of embodiments in this application does not specifically limit the scope of the invention.

[0068] Step C: Based on the first curve, determine the lithium-powder charge state of the electrochemical device.

[0069] The first curve represents the mapping relationship between the state of charge and internal resistance of an electrochemical device. The lithium plating state of charge of the electrochemical device can be determined based on the first curve.

[0070] The aforementioned lithium plating state of charge may not be measured in real time, but rather obtained by looking up the charging voltage obtained during intermittent charging operations and the correspondence table between the charging voltage and the state of charge. This correspondence table can be pre-stored in the storage medium of the battery management system, electrochemical device, or electronic device.

[0071] In one embodiment, the process of determining the lithium-plating state of the electrochemical device based on the first curve can be method 1, which includes:

[0072] a: Taking the first derivative of the first curve, we obtain the second curve;

[0073] like Figure 3 As shown, the second curve is obtained by taking the first derivative of the first curve. This second curve represents the rate of change of the internal resistance of the electrochemical device with respect to the state of charge.

[0074] b: Determine the state of charge corresponding to the first point on the second curve with a negative slope as the lithium plating state.

[0075] The second curve represents the rate of change of internal resistance with respect to the state of charge. When the rate of change does not show an abnormal decrease in the flat region of the curve, it indicates that no active lithium has been deposited. When the rate of change shows an abnormal decrease in the flat region of the curve, it is because active lithium has been deposited on the surface of the negative electrode and is in contact with the negative electrode. This is equivalent to a lithium metal device being connected in parallel with the graphite part of the negative electrode, which reduces the impedance of the entire negative electrode. Therefore, the impedance of the electrochemical device shows an abnormal decrease when active lithium is deposited, and correspondingly, the flat region of the second curve shows an abnormal decrease. (Reference) Figure 3 Point B marks the first time the slope of the second curve becomes negative. This means that the flat area of ​​the second curve at point B experiences its first abnormal decrease, indicating that the electrochemical device is showing a tendency to or has already undergone lithium plating at point B. Therefore, the state of charge corresponding to point B can be determined as the lithium plating state of charge. Based on the relationship between the lithium plating state of charge and the state of charge threshold, timely protection measures can be taken for the electrochemical device, improving its operational safety. Steps a to c above are only used to illustrate the order of the steps, not to limit their sequence.

[0076] In one embodiment, the process of determining the lithium-plating state of the electrochemical device based on the first curve can be method 2, which includes:

[0077] a': Taking the first derivative of the first curve yields the second curve;

[0078] This step is the same as step a in method 1, and will not be repeated here.

[0079] b': Taking the second derivative of the second curve yields the third curve;

[0080] The second curve can also be differentiated by its second order to obtain the third curve. It can be understood that the third curve is the second-order differential curve of the second curve.

[0081] c': Determine the state of charge corresponding to the point where the ordinate of the third curve first appears to be less than zero as the lithium plating state.

[0082] If the third curve shows a point where the ordinate is less than zero, then the state of charge corresponding to the first point where the ordinate of the third curve is less than zero is determined as the lithium plating state of charge.

[0083] In one embodiment, the electrochemical device management method of this application may further include:

[0084] The target charging current is determined based on at least one of the charging current or the state of charge threshold, and a pre-established mapping relationship between charging current and lithium-degraded state of charge.

[0085] The charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current. Referring to Table 1, which shows the charging current-lithium plating state of charge mapping relationship established in the embodiments of this application, the table records multiple charging currents and the lithium plating state of charge corresponding to each charging current.

[0086] Table 1

[0087] Charging current (rate) Lithium plating state of charge 2.5C 30％

[0088] 2.4C 35％ 2.3C 38％ 2.2C 42％ 2.1C 46％ 2C 49％ 1.9C 51％ 1.8C 53％ 1.7C 56％ 1.6C 61％ 1.5C 66％ 1.4C 68％ 1.3C 70％ 1.2C 76％ 1.1C 78％ 1C 81％

[0089] As shown in Table 1, the charging currents gradually decrease from top to bottom, while the lithium plating state of charge corresponding to each charging current gradually increases. Since the charging current is proportional to the charging rate when the capacity of the electrochemical device is constant, the charging current is expressed as the charging rate in Table 1 for ease of calculation. Here, 1C (rate) = charging current corresponding to the capacity of the electrochemical device. The interval values ​​of the above charging currents can be set according to actual needs; there are no special limitations in the embodiments of this application. Correspondingly, the interval values ​​of the lithium plating state of charge are also smaller.

[0090] As an optional implementation of this application, the step of determining the target charging current based on at least one of charging current or state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, includes:

[0091] The target charging current is determined by identifying the charging current value that is closest to the current value in the mapping relationship.

[0092] For example, if the charging current of the first charge-discharge cycle is 2.4C, as shown in Table 1, the charging current value that is closest to 2.4C and less than 2.4C is 2.3C, then the charging current of 2.3C can be determined as the target charging current.

[0093] As another optional implementation of this application, the step of determining the target charging current based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, includes:

[0094] The target lithium plating state of charge (PPC) is determined by identifying the PCC state that is greater than the PCC threshold and has the smallest difference from the PCC threshold in the mapping relationship, and the charging current corresponding to the target PCC state of charge is determined as the target charging current.

[0095] In some embodiments, the target lithium plating state of charge (SPC) can be determined based on a comparison between each SPC in Table 1 and the SPC threshold, thereby determining the target charging current. For example, if the SPC threshold is 49%, the SPC greater than 49% with the smallest difference from 49% is found in Table 1, resulting in 51%. 51% is taken as the target SPC, and the charging current corresponding to 51%, i.e., 1.9C, is the target charging current.

[0096] The embodiments of this application determine the target charging current by mapping the charging current to the lithium plating state of charge, which can reduce the charging current of the electrochemical device to the target charging current to reduce the risk of lithium plating and improve the safety of the electrochemical device.

[0097] In another embodiment, the electrochemical device management method of this application may further include:

[0098] The target charging current is determined based on at least one of the charging current or the state of charge threshold, the current ambient temperature, and a pre-established temperature-charging current-lithium plating state of charge mapping relationship.

[0099] The temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, a charging current, and at least one lithium plating state of charge corresponding to the at least one charging current. Referring to Table 2, Table 2 shows the temperature-charging current-lithium plating state of charge mapping relationship established in the embodiments of this application under different ambient temperatures. The table records at least one ambient temperature, such as 5°C, 25°C, and 45°C, as well as the charging current at each ambient temperature and the lithium plating state of charge corresponding to each charging current.

[0100] Table 2

[0101]

[0102] In Table 2, " / " represents a blank space.

[0103] As can be seen from Table 2, at the same temperature, the charging currents gradually decrease from top to bottom, while the lithium plating state of charge corresponding to each charging current gradually increases. Since the electrochemical device can operate at different ambient temperatures, Table 2 of this application's embodiments records the correspondence between the charging current and the lithium plating state of charge when the electrochemical device operates at different ambient temperatures.

[0104] Tables 1 and 2 above can be stored as data in a storage medium, such as the storage medium of a battery management system, an electrochemical device, or an electronic device. The processor of the battery management system / electrochemical device / electronic device can read the mapping relationship data stored in the storage medium.

[0105] As an optional implementation of this application, the step of determining the target charging current based on at least one of charging current or state of charge threshold, the current ambient temperature, and a pre-established mapping relationship between charging current and lithium plating state of charge includes:

[0106] Under the current ambient temperature, determine the target charging current value that is closest to the charging current in the mapping relationship.

[0107] For example, if the current operating temperature of the electrochemical device is 25°C, and the charging current of the first charge-discharge cycle is 2.4C, as shown in Table 2, the charging current value closest to 2.4C and less than 2.4C is 2.3C. Therefore, the charging current of 2.3C can be determined as the target charging current, that is, the target charging current of the electrochemical device at an ambient temperature of 25°C is 2.3C.

[0108] As another optional implementation of this application, the step of determining the target charging current based on at least one of charging current or state of charge threshold, the current ambient temperature, and a pre-established charging current-lithium plating state of charge mapping relationship includes:

[0109] Under the current ambient temperature, the lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference from the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

[0110] For example, if the current operating temperature of the electrochemical device is 25°C and the state of charge threshold is 49%, then in the 25°C data column of Table 2, the lithium plating state of charge that is greater than 49% and has the smallest difference from 49% is found, which is 51%. Taking 51% as the target lithium plating state of charge, the charging current corresponding to 51%, i.e., 1.9C, is the target charging current. That is, the target charging current of the electrochemical device at an ambient temperature of 25°C is 1.9C.

[0111] This application embodiment determines the target charging current by mapping the temperature-charging current-lithium plating state of charge relationship. It can reduce the charging current of the electrochemical device to the target charging current for electrochemical devices under different ambient temperatures, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device when operating under different ambient temperatures.

[0112] In one embodiment, after reducing the charging current and cycling a second time, the electrochemical device can be intermittently charged again. When the lithium plating state of charge of the electrochemical device is less than the state of charge threshold, the charging current is reduced again according to the charging current shown in Table 1 or Table 2 until the charging current is reduced to the minimum current in Table 1 or Table 2, thereby controlling the electrochemical device to stop working and further improving the safety of the electrochemical device.

[0113] In one embodiment, the intermittent charging operation may include multiple charging cycles, each charging cycle including a charging period and an intermittent period, wherein the state of charge of the electrochemical device increases by a unit magnitude during each charging period, that is, the state of charge of the electrochemical device is increased by a certain magnitude during each charging period, for example, by 0.5% SOC, 1% SOC, 5% SOC or 10% SOC during each charging period.

[0114] The intermittent charging operation of this application embodiment includes multiple charging cycles, each charging cycle including a charging period and an interruption period. Exemplarily, a first charging period and a first interruption period form a first charging cycle, a second charging period and a second interruption period form a second charging cycle, a third charging period and a third interruption period form a third charging cycle, and so on. It is understood that a charging cycle is a continuous time period.

[0115] For example, the electrochemical device is charged during the first charging period, then charging is stopped. After a first interruption period, charging continues during the second charging period, and this process is repeated until the state of charge of the electrochemical device reaches a first critical value. It is understood that as intermittent charging proceeds, the state of charge of the electrochemical device increases. In this embodiment, intermittent charging can be stopped when the state of charge of the electrochemical device reaches the first critical value, thus completing the intermittent charging operation. This embodiment does not impose any particular limitation on the first critical value, as long as the purpose of this application is achieved. For example, the first critical value can be 60%, 70%, 80%, 90%, or 100%.

[0116] During intermittent charging operations, the unit amplitude of the state of charge (SOC) can differ for different charging cycles. For example, during the first charging period, the electrochemical device is charged, and after the SOC increases by 1%, charging is stopped. After a 5-second interval, the electrochemical device is charged again during the second charging period, and after the SOC increases by 5%, charging is stopped. After a 5-second interval, the electrochemical device is charged again during the third charging period, and after the SOC increases by 3%, charging is stopped. This process is repeated until the SOC of the electrochemical device reaches a first threshold.

[0117] In one implementation, the intermittent charging operation can be specifically described as follows: For any one of multiple charging cycles, the electrochemical device is charged at a first moment until the state of charge of the electrochemical device increases by a unit magnitude, at which point charging stops, until a third moment. The moment when charging stops is the second moment, and the time interval between the third moment and the second moment is the duration of the intermittent period. During the intermittent period, the electrochemical device can be in a state of neither charging nor discharging, i.e., a static state.

[0118] For example, if the electrochemical device is charged at time T1 until the state of charge of the electrochemical device increases by a unit magnitude, then the charging stops at time T2; and the electrochemical device is left to stand from time T2, then the standing time ends at time T3.

[0119] This application embodiment, by performing intermittent charging operation on the electrochemical device, can obtain data related to the electrochemical device during the intermittent charging operation. Based on this data, the lithium plating state of the electrochemical device is determined, thereby performing the steps of continuing to cycle at the original charging current or cycling at a reduced current on the electrochemical device. This helps to reduce the risk of lithium plating in the electrochemical device and extend the service life of the electrochemical device.

[0120] The electrochemical device in this application includes at least one of a lithium iron phosphate system, a lithium nickel cobalt manganese oxide system, or a lithium cobalt oxide system. Generally, in intermittent charging operations, different electrochemical systems correspond to different unit amplitudes and different intermittent periods. Based on this:

[0121] In one embodiment, the electrochemical device is a lithium iron phosphate system electrochemical device, with a unit amplitude ranging from 0.5% to 10% and an intermittent period duration ranging from 1 second to 15 seconds.

[0122] In one embodiment, the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, with a unit amplitude ranging from 0.5% to 10% and an intermittent period duration ranging from 1 second to 30 seconds.

[0123] In one embodiment, the electrochemical device is a lithium cobalt oxide system electrochemical device, with a unit amplitude ranging from 0.5% to 10% and an intermittent period duration ranging from 1 second to 30 seconds.

[0124] This application embodiment sets different unit amplitudes and intermittent periods for electrochemical devices of different systems, enabling more targeted intermittent charging operations for electrochemical devices of different systems, and more accurately obtaining the lithium plating state of charge of electrochemical devices of different systems.

[0125] Generally speaking, in intermittent charging operations, for the same electrochemical device system, different temperature conditions will correspond to different unit amplitudes and different durations of interruptions. Based on this:

[0126] In one embodiment, the electrochemical device is a lithium iron phosphate system electrochemical device, operating at an ambient temperature of -10°C to 10°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 5 seconds to 15 seconds. In another embodiment, the electrochemical device is a lithium iron phosphate system electrochemical device, operating at an ambient temperature of 10°C to 45°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 1 second to 10 seconds.

[0127] In the embodiments of this application, the positive electrode of the lithium iron phosphate system electrochemical device may also include other positive electrode active materials, but lithium iron phosphate is the main material. For example, lithium iron phosphate accounts for any one of 51%, 60%, 70%, 80%, 90%, or 98% of the total mass of the positive electrode active material.

[0128] In one embodiment, the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, operating at an ambient temperature of -10°C to 10°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 10 seconds to 30 seconds. In another embodiment, the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, operating at an ambient temperature of 10°C to 45°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 1 second to 10 seconds.

[0129] In the embodiments of this application, the positive electrode of the lithium nickel cobalt manganese oxide system electrochemical device may also include other positive electrode active materials, but lithium nickel cobalt manganese oxide is the main material. For example, lithium nickel cobalt manganese oxide accounts for any of the following values ​​of the total mass of the positive electrode active material: 51%, 60%, 70%, 80%, 90%, and 98%.

[0130] In one embodiment, the electrochemical device is a lithium cobalt oxide system electrochemical device, operating at an ambient temperature of -10°C to 10°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 15 seconds to 30 seconds. In another embodiment, the electrochemical device is a lithium cobalt oxide system electrochemical device, operating at an ambient temperature of 10°C to 45°C, with a unit amplitude ranging from 0.5% to 10%, and an intermittent period duration ranging from 1 second to 10 seconds.

[0131] In the embodiments of this application, the positive electrode of the lithium cobalt oxide system electrochemical device may also include other positive electrode active materials, but lithium cobalt oxide is the main material. For example, lithium cobalt oxide accounts for any of the following values ​​of the total mass of the positive electrode active material: 51%, 60%, 70%, 80%, 90%, and 98%.

[0132] This application embodiment sets different unit amplitudes and intermittent durations for electrochemical devices in the same system at different temperatures, enabling more targeted intermittent charging operations for electrochemical devices in different temperature environments, and more accurately obtaining the lithium deposition state of electrochemical devices in different systems.

[0133] The state of charge (SCC) threshold refers to the state of charge corresponding to lithium plating in an electrochemical device, and it is usually related to the system of the electrochemical device. The SCC threshold in the embodiments of this application can be set according to actual needs, and can vary based on the characteristics of different electrochemical device systems. For example, for a lithium iron phosphate system electrochemical device, the SCC threshold ranges from 30% to 70%, such as 30%, 40%, 50%, 60%, or 70%; for a lithium nickel cobalt manganese oxide system electrochemical device, the SCC threshold ranges from 20% to 50%, such as 20%, 30%, 40%, or 50%; and for a lithium cobalt oxide system electrochemical device, the SCC threshold ranges from 20% to 50%, such as 20%, 30%, 40%, or 50%.

[0134] By setting different state-of-charge thresholds for electrochemical devices of different systems, management strategies for these devices can be optimized more effectively, thereby extending their safe service life.

[0135] In one implementation, the step of generating the first curve includes:

[0136] Step a: Obtain the first voltage, first current and first state of charge of the electrochemical device at the second time point, and the second voltage and second current of the electrochemical device at the third time point;

[0137] The second moment is the moment when charging stops. The voltage, current, and state of charge of the electrochemical device at the second moment can be obtained, namely the first voltage, the first current, and the first state of charge, denoted as V1, I1, and SOC1, respectively. Similarly, the voltage and current of the electrochemical device at the third moment can be obtained, namely the second voltage and the second current, denoted as V2 and I2, respectively.

[0138] Step b: Calculate the voltage and current changes of the electrochemical device during the intermittent period.

[0139] The duration of the interruption is the time interval between the third moment and the second moment. The voltage change of the electrochemical device during the interruption is ΔV, where ΔV = V2 - V1. The current change of the electrochemical device during the interruption is ΔI, where ΔI = I2 - I1.

[0140] Step c: Calculate the first internal resistance of the electrochemical device during the intermittent period based on the voltage change value and the current change value, and use the first internal resistance and the first state of charge as one of the data pairs of the first curve, wherein the data pair is the correspondence between internal resistance and state of charge.

[0141] The first internal resistance of the electrochemical device during the intermittent period is R1, where R1 = ΔV / ΔI. R1 and SOC1 are used as one data pair for the first curve.

[0142] Multiple data pairs can be obtained by using the same method described above.

[0143] Step d: Generate the first curve based on the calculated data pairs.

[0144] Using the state of charge (SOC) of the electrochemical device as the x-axis and the internal resistance of the electrochemical device as the y-axis, the points represented by these data pairs are filled into a coordinate system, and a first curve is obtained after fitting. After obtaining the first curve in this embodiment, the lithium plating SOC of the electrochemical device can be determined through the first curve. Furthermore, based on the relationship between the lithium plating SOC and the SOC threshold, the electrochemical device can be cycled using either the original charging current or a reduced current, which helps reduce the risk of lithium plating and extends the lifespan of the electrochemical device.

[0145] This application provides an electrochemical device management method that determines the lithium plating state of charge of the electrochemical device based on data related to the electrochemical device obtained during intermittent charging operations. In response to the lithium plating state of charge of the electrochemical device being less than or equal to the state of charge threshold, the electrochemical device is charged with a smaller charging current, i.e., a target charging current. This reduces the charging current of the electrochemical device, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device.

[0146] This application embodiment also provides a system 400, which may include a battery management system, such as... Figure 4 As shown, the system 400 includes: a charging / discharging device 401 and a state of charge analysis device 402, wherein,

[0147] The charge / discharge device 401 is used to perform a first charge / discharge cycle on the electrochemical device with a charging current.

[0148] The state of charge analysis device 402 is used to perform intermittent charging operation on the electrochemical device with a detection current, acquire data related to the electrochemical device during the intermittent charging operation, and determine the lithium plating state of the electrochemical device based on the data related to the electrochemical device.

[0149] The charge / discharge device 401 is further configured to perform a second charge / discharge cycle on the electrochemical device with a charging current in response to the lithium plating state of charge of the electrochemical device being greater than the state of charge threshold; or, in response to the lithium plating state of charge of the electrochemical device being less than or equal to the state of charge threshold, perform a second charge / discharge cycle on the electrochemical device with a target charging current, wherein the target charging current is less than the charging current.

[0150] The embodiments of this application do not impose any particular restrictions on the structure of the charge-discharge device 401 and the state-of-charge analysis device 402, as long as the corresponding functions can be achieved.

[0151] In one implementation, the intermittent charging operation includes multiple charging periods and multiple interruptions, and the state of charge analysis device is specifically used for:

[0152] In intermittent charging operation, for each of the multiple intermittent periods, the state of charge and internal resistance of the electrochemical device during that intermittent period are acquired. Based on the acquired multiple states of charge and the multiple internal resistances of the electrochemical device corresponding to the multiple states of charge, a first curve is obtained. The first curve is a mapping curve corresponding to the state of charge and internal resistance of the electrochemical device. Based on the first curve, the lithium plating state of charge of the electrochemical device is determined.

[0153] In one implementation, the state of charge analysis device is specifically used for:

[0154] The first curve is differentiated to obtain the second curve; and the state of charge corresponding to the first point where the slope of the second curve is negative is determined as the lithium plating state of charge. It is understood that the determination of the first point where the slope of the second curve is negative can employ techniques known to those skilled in the art, and this application does not limit it. As an example, this application uses the following method to test the first point where the slope of the second curve is negative: based on data points adjacent to each two states of charge, the slope is calculated. The points where the slope is negative for the first time are denoted as point 1 and point 2. The point with the larger state of charge between point 1 and point 2 is the point where the slope of the second curve is negative for the first time.

[0155] or

[0156] The first curve is differentiated by first order to obtain the second curve; and the second curve is differentiated by second order to obtain the third curve; the charging state corresponding to the first point on the third curve where the ordinate is less than zero is determined to be the lithium plating charging state.

[0157] In one embodiment, the charging and discharging device is also used for:

[0158] Based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, a target charging current is determined. The charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current.

[0159] In one embodiment, the charging and discharging device is specifically used for:

[0160] The target charging current is determined by identifying the charging current value closest to the current value in the mapping relationship; or

[0161] The target lithium plating state of charge (PPC) is determined by identifying the PCC state that is greater than the PCC threshold and has the smallest difference from the PCC threshold in the mapping relationship, and the charging current corresponding to the target PCC state of charge is determined as the target charging current.

[0162] In one embodiment, the charging and discharging device is also used for:

[0163] Based on at least one of the charging current or state of charge threshold, the target charging current is determined by the current ambient temperature and a pre-established temperature-charging current-lithium plating state of charge mapping relationship. The temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, charging current, and at least one lithium plating state of charge corresponding to at least one charging current.

[0164] In one embodiment, the charging and discharging device is specifically used for:

[0165] Under the current ambient temperature, determine the target charging current as the charging current value that is closest to the current value in the mapping relationship; or

[0166] Under the current ambient temperature, the lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference from the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

[0167] In one embodiment, the intermittent charging operation includes multiple charging cycles, each charging cycle including a charging period and an intermittent period, during which the state of charge of the electrochemical device increases by a unit magnitude.

[0168] In one embodiment, the electrochemical device includes at least one of a lithium iron phosphate system electrochemical device, a lithium nickel cobalt manganese oxide system electrochemical device, or a lithium cobalt oxide system electrochemical device, wherein the state of charge analysis device is specifically used for:

[0169] The electrochemical device is a lithium iron phosphate system electrochemical device, with a unit amplitude ranging from 0.5% to 10% and an intermittent duration ranging from 1 second to 15 seconds;

[0170] The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, with a unit amplitude ranging from 0.5% to 10% and an intermittent duration ranging from 1 second to 30 seconds;

[0171] The electrochemical device is a lithium cobalt oxide system electrochemical device with a unit amplitude ranging from 0.5% to 10% and an intermittent period duration ranging from 1 second to 30 seconds.

[0172] In one embodiment, the state of charge analysis device is specifically used for at least one of the following a) to f):

[0173] a) The electrochemical device is a lithium iron phosphate system electrochemical device, the electrochemical device is in an ambient temperature of -10℃ to 10℃, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 5 seconds to 15 seconds;

[0174] b) The electrochemical device is a lithium iron phosphate system electrochemical device, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds;

[0175] c) The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the electrochemical device is in an ambient temperature of -10℃ to 10℃, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 10 seconds to 30 seconds;

[0176] d) The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device. The electrochemical device is in an ambient temperature range of 10°C to 45°C, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds.

[0177] e) The electrochemical device is a lithium cobalt oxide system electrochemical device, the electrochemical device is in an ambient temperature of -10℃ to 10℃, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 15 seconds to 30 seconds;

[0178] f) The electrochemical device is a lithium cobalt oxide system electrochemical device, which is operated at an ambient temperature of 10°C to 45°C, with a unit amplitude range of 0.5% to 10%, and an intermittent period duration range of 1 second to 10 seconds.

[0179] The system provided in this application embodiment includes a state of charge (SCC) analysis device that performs intermittent charging operations on an electrochemical device. During the intermittent charging operation, it acquires data related to the electrochemical device and determines the lithium plating SCC of the electrochemical device based on the data. When the lithium plating SCC is less than or equal to the SCC threshold, the electrochemical device is charged with a smaller charging current, i.e., a target charging current. This reduces the charging current of the electrochemical device, thereby reducing the risk of lithium plating and improving the safety of the electrochemical device.

[0180] This application also provides a charging device, such as... Figure 5 As shown, the charging device 500 includes a processor 501 and a machine-readable storage medium 502. The charging device 500 may also include a detection circuit module 503, a charging / discharging circuit 504, an interface 505, a power interface 506, and a rectifier circuit 507. The detection circuit module 503 is used to perform intermittent charging operations on the lithium-ion battery 605 to detect the lithium-ion battery's state of charge (SOC) and send the detection results to the processor 501. The charging / discharging circuit 504 is used to receive instructions from the processor 501 to charge or discharge the lithium-ion battery 605. The interface 505 is used for electrical connection to the lithium-ion battery 605. The power interface 506 is used for connection to an external power source. The rectifier circuit 507 is used to rectify the input current. The machine-readable storage medium 502 stores machine-executable instructions that can be executed by the processor. When the processor 501 executes the machine-executable instructions, it implements the steps described in any of the above embodiments.

[0181] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the method described in any of the above embodiments.

[0182] This application also provides a system, such as Figure 6As shown, the system 600 includes a second processor 601 and a second machine-readable storage medium 602. The system 600 may also include a detection circuit module 603, a charging / discharging circuit 604, a lithium-ion battery 605, and a second interface 606. The detection circuit module 603 performs intermittent charging operations on the lithium-ion battery 605 to detect the lithium-ion battery's state of charge (SOC), and sends the detection result to the second processor 601. The charging / discharging circuit 604 receives instructions from the second processor 601 to charge or discharge the lithium-ion battery 605. The second interface 606 connects to an external charger 700, which provides power. The second machine-readable storage medium 602 stores machine-executable instructions that can be executed by the processor. When the second processor 601 executes the machine-executable instructions, it implements the steps described in any of the above embodiments. The external charger 700 may include a first processor 701, a first machine-readable storage medium 702, a first interface 703, and a corresponding rectifier circuit. The external charger may be a commercially available charger, and the structure of the present application embodiment is not specifically limited.

[0183] This application also provides an electronic device, including the electrochemical device described in the above embodiments. The electronic device in this application may include an electrochemical device. For example, the electronic device may be a mobile phone, tablet computer, or other device with a built-in lithium-ion battery and data processing capabilities.

[0184] Machine-readable storage media may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0185] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0186] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0187] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0188] For the system / electronic device / charging device / storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and relevant parts can be referred to in the description of the method embodiments.

[0189] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electrochemical device management method, wherein, The method includes: i. The electrochemical device is subjected to a first charge-discharge cycle using the charging current; ii. The electrochemical device is intermittently charged using a detection current, and data related to the electrochemical device is acquired during the intermittent charging operation. The lithium plating state of the electrochemical device is determined based on the data related to the electrochemical device. iii-1 In response to the lithium plating state of the electrochemical device being greater than the state of charge threshold, the electrochemical device is subjected to a second charge-discharge cycle with the charging current; or iii-2 In response to the lithium plating state of charge of the electrochemical device being less than or equal to the state of charge threshold, a second charge-discharge cycle is performed on the electrochemical device with a target charging current, wherein the target charging current is less than the charging current.

2. The electrochemical device management method according to claim 1, wherein The electrochemical device management method also includes: After step iii-1, repeat step ii and steps iii-1 or iii-2; or After step iii-2, repeat step ii and steps iii-1 or iii-2.

3. The electrochemical device management method according to claim 1, wherein The data related to the electrochemical device includes the state of charge and internal resistance of the electrochemical device. The intermittent charging operation includes multiple charging periods and multiple interruptions. The step of acquiring the data related to the electrochemical device during the intermittent charging operation and determining the lithium plating state of charge of the electrochemical device based on the data related to the electrochemical device includes: In intermittent charging operation, for each of the plurality of intermittent periods, the state of charge and internal resistance of the electrochemical device during that intermittent period are obtained; Based on the multiple states of charge of the electrochemical device and the multiple internal resistances of the electrochemical device corresponding to the multiple states of charge, a first curve is obtained. The first curve is a mapping curve corresponding to the states of charge and internal resistance of the electrochemical device. Based on the first curve, the lithium-plating state of the electrochemical device is determined.

4. The electrochemical device management method according to claim 3, wherein The step of determining the lithium plating state of the electrochemical device based on the first curve includes at least one of method 1 or method 2, wherein: Method 1 includes: Taking the first derivative of the first curve yields the second curve; and The state of charge corresponding to the first point on the second curve with a negative slope is determined as the lithium plating state of charge. Method 2 includes: The second curve is obtained by taking the first derivative of the first curve; Taking the second derivative of the second curve yields the third curve; and The state of charge corresponding to the first point on the third curve where the ordinate is less than zero is determined as the lithium plating state of charge.

5. The electrochemical device management method according to claim 1, wherein The method further includes: The target charging current is determined based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, wherein the charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current.

6. The electrochemical device management method according to claim 5, wherein The step of determining the target charging current based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship includes: The target charging current is determined by identifying the charging current value in the mapping relationship that is closest to the charging current; or The lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference with the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

7. The electrochemical device management method according to claim 1, wherein The method further includes: Based on at least one of the charging current or the state of charge threshold, the target charging current is determined by the current ambient temperature and a pre-established temperature-charging current-lithium plating state of charge mapping relationship, wherein the temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, the charging current and at least one lithium plating state of charge corresponding to the at least one charging current.

8. The electrochemical device management method according to claim 7, wherein The step of determining the target charging current based on at least one of the charging current or the state of charge threshold, the current ambient temperature, and a pre-established charging current-lithium plating state of charge mapping relationship includes: Under the current ambient temperature, determine the charging current value that is closest to the charging current in the mapping relationship as the target charging current; or Under the current ambient temperature, the lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference with the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

9. The electrochemical device management method according to claim 1, wherein The intermittent charging operation includes multiple charging cycles, each charging cycle including a charging period and an intermittent period, during which the state of charge of the electrochemical device increases by a unit magnitude.

10. The electrochemical device management method according to claim 9, wherein, The electrochemical device comprises at least one of lithium iron phosphate system electrochemistry, lithium nickel cobalt manganese oxide, or lithium cobalt oxide, wherein... The electrochemical device is a lithium iron phosphate system electrochemical device, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 15 seconds; The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds; The electrochemical device is a lithium cobalt oxide system electrochemical device, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds.

11. The electrochemical device management method according to claim 9, wherein The method satisfies at least one of conditions a) to f): a) The electrochemical device is a lithium iron phosphate system electrochemical device, the electrochemical device is in an ambient temperature of -10℃ to 10℃, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 5 seconds to 15 seconds; b) The electrochemical device is a lithium iron phosphate system electrochemical device, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds; c) The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 10 seconds to 30 seconds; d) The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds; e) The electrochemical device is a lithium cobalt oxide system electrochemical device, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 15 seconds to 30 seconds; f) The electrochemical device is a lithium cobalt oxide system electrochemical device, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds.

12. A computer readable storage medium, wherein, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method described in any one of claims 1-11.

13. A charging device comprising a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, wherein the processor, when executing the machine-executable instructions, implements the method of any one of claims 1-11.

14. An electrochemical device, wherein, The method includes a processor and a machine-readable storage medium storing machine-executable instructions that can be executed by the processor, wherein when the processor executes the machine-executable instructions, it implements the method according to any one of claims 1-11.

15. An electronic device comprising the electrochemical device as described in claim 14.

16. A system in which, The system includes: a charging / discharging device and a state of charge analysis device, wherein... The charge-discharge device is used to perform a first charge-discharge cycle on the electrochemical device with a charging current. The state of charge analysis device is used to perform intermittent charging operation on the electrochemical device with a detection current, acquire data related to the electrochemical device during the intermittent charging operation, and determine the lithium plating state of the electrochemical device based on the data related to the electrochemical device. The charging and discharging device is further configured to perform a second charging and discharging cycle on the electrochemical device with the charging current in response to the lithium plating state of the electrochemical device being greater than the state of charge threshold. or In response to the lithium plating state of charge of the electrochemical device being less than or equal to a state of charge threshold, a second charge-discharge cycle is performed on the electrochemical device with a target charging current, wherein the target charging current is less than the charging current.

17. The system according to claim 16, wherein, The data related to the electrochemical device includes the state of charge and internal resistance of the electrochemical device. The intermittent charging operation includes multiple charging periods and multiple interruptions. The state of charge analysis device is specifically used for: In the intermittent charging operation, for each of the plurality of intermittent periods, the state of charge and internal resistance of the electrochemical device during that intermittent period are obtained. Based on the plurality of states of charge of the electrochemical device and the plurality of internal resistances of the electrochemical device corresponding to the plurality of states of charge, a first curve is obtained. The first curve is a mapping curve corresponding to the state of charge and internal resistance of the electrochemical device. and Based on the first curve, the lithium-plating state of the electrochemical device is determined.

18. The system according to claim 17, wherein, The state of charge analysis device is specifically used for: Taking the first derivative of the first curve yields the second curve; and The state of charge corresponding to the first point on the second curve with a negative slope is determined as the lithium plating state of charge. or The second curve is obtained by taking the first derivative of the first curve; and Taking the second derivative of the second curve yields the third curve; The state of charge corresponding to the first point on the third curve where the ordinate is less than zero is determined as the lithium plating state of charge.

19. The system according to claim 16, wherein, The charging and discharging device is also used for: The target charging current is determined based on at least one of the charging current or the state of charge threshold, and a pre-established charging current-lithium plating state of charge mapping relationship, wherein the charging current-lithium plating state of charge mapping relationship includes at least one charging current and at least one lithium plating state of charge corresponding to the at least one charging current.

20. The system according to claim 19, wherein, The charging and discharging device is specifically used for: The target charging current is determined by identifying the charging current value in the mapping relationship that is closest to the charging current; or The lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference with the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

21. The system according to claim 16, wherein, The charging and discharging device is also used for: Based on at least one of the charging current or the state of charge threshold, the target charging current is determined by the current ambient temperature and a pre-established temperature-charging current-lithium plating state of charge mapping relationship, wherein the temperature-charging current-lithium plating state of charge mapping relationship includes at least one ambient temperature, the charging current and at least one lithium plating state of charge corresponding to the at least one charging current.

22. The system according to claim 21, wherein, The charging and discharging device is specifically used for: Under the current ambient temperature, determine the charging current value that is closest to the charging current in the mapping relationship as the target charging current; or Under the current ambient temperature, the lithium plating state of charge that is greater than the state of charge threshold and has the smallest difference with the state of charge threshold in the mapping relationship is determined as the target lithium plating state of charge, and the charging current corresponding to the target lithium plating state of charge is determined as the target charging current.

23. The system according to claim 16, wherein, The intermittent charging operation includes multiple charging cycles, each charging cycle including a charging period and an intermittent period, during which the state of charge of the electrochemical device increases by a unit magnitude.

24. The system according to claim 23, wherein, The electrochemical device includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, or lithium cobalt oxide, wherein the state of charge analysis device is specifically used for: The electrochemical device includes lithium iron phosphate, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption ranges from 1 second to 15 seconds; The electrochemical device includes lithium nickel cobalt manganese oxide, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds; The electrochemical device includes lithium cobalt oxide, the unit amplitude ranges from 0.5% to 10%, and the duration of the interruption ranges from 1 second to 30 seconds.

25. The system according to claim 24, wherein, The state of charge analysis device is specifically used for at least one of the following a) to f): a) The electrochemical device comprises lithium iron phosphate, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 5 seconds to 15 seconds; b) The electrochemical device includes lithium iron phosphate, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds; c) The electrochemical device includes lithium nickel cobalt manganese oxide, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 10 seconds to 30 seconds; d) The electrochemical device includes lithium nickel cobalt manganese oxide, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds; e) The electrochemical device includes lithium cobalt oxide, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 15 seconds to 30 seconds; f) The electrochemical device includes lithium cobalt oxide, the electrochemical device is in an ambient temperature of 10°C to 45°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 10 seconds.

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