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

Abstract

Embodiments of the present application provide an electrochemical device management method and system, an electrochemical device and an electronic device, including: obtaining a first parameter of an electrochemical device; in response to the first parameter satisfying a first condition, performing an intermittent charging operation on the electrochemical device, obtaining data related to the electrochemical device in the intermittent charging operation, determining a lithium precipitation SOC of the electrochemical device based on the data related to the electrochemical device; in response to the lithium precipitation SOC of the electrochemical device being less than or equal to a first SOC threshold, controlling the electrochemical device to stop working; and in response to the lithium precipitation SOC of the electrochemical device being greater than the first SOC threshold and less than a second SOC threshold, reducing at least one of a charging voltage or a charging current of the electrochemical device. Embodiments of the present application can reduce the safety hazards caused by the continued use of the electrochemical device after lithium precipitation, and improve the safety of the electrochemical device during use.

Description

Technical Field

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

[0002] Lithium-ion batteries have many advantages, such as high energy density, long cycle life, high nominal voltage, low self-discharge rate, small size, and light weight, and are widely used in the consumer electronics field.

[0003] In recent years, with the rapid development of consumer electronics products such as tablets and mobile phones, the market demand for lithium-ion batteries has also increased. However, during the use of lithium-ion batteries, lithium plating can occur due to side reactions, impacts, and other reasons, which can easily cause short circuits and pose safety risks, affecting the safety of the battery. Summary of the Invention

[0004] The purpose of this application is to provide an electrochemical device management method, system, electrochemical device, and electronic device to improve the safety of electrochemical devices during use.

[0005] A first aspect of this application provides an electrochemical device management method, comprising: acquiring a first parameter of the electrochemical device; performing an intermittent charging operation on the electrochemical device in response to the first parameter satisfying a first condition, acquiring data related to the electrochemical device during the intermittent charging operation, and determining the lithium plating state occupancy (SOC) of the electrochemical device based on the data related to the electrochemical device; controlling the electrochemical device to stop operating in response to the lithium plating SOC of the electrochemical device being less than or equal to a first SOC threshold; or reducing at least one of the charging voltage or charging current of the electrochemical device in response to the lithium plating SOC of the electrochemical device being greater than the first SOC threshold and less than a second SOC threshold.

[0006] The technical effects of this application's embodiments are as follows: This application's embodiments perform intermittent charging operations on the electrochemical device, acquire data related to the electrochemical device during the intermittent charging operation, determine the lithium plating state of the electrochemical device based on the relevant data, and then control the electrochemical device to stop working or reduce at least one of the charging voltage or charging current of the electrochemical device based on the relationship between the lithium plating state of the electrochemical device and the first state of the first state of the second state of the second state of the third state of the fourth state of the fifth state of the sixth ...

[0007] 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 includes: during the intermittent charging operation, for each of the multiple interrupted periods, acquiring the SOC and internal resistance of the electrochemical device during that interrupted period; obtaining a first curve based on the acquired multiple SOCs of the electrochemical device 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.

[0008] In one embodiment of this application, the intermittent charging operation includes multiple charging cycles, each charging cycle including a charging period and an intermittent period. During each charging period, the SOC of the electrochemical device increases by a unit magnitude. This application embodiment 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.

[0009] In one embodiment of this application, 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. Specifically, 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; and 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. This application embodiment 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.

[0010] In one embodiment of this application, the method satisfies any one of conditions a) to f): a) the electrochemical device is a lithium iron phosphate system electrochemical device, the electrochemical device is 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 is a lithium iron phosphate system electrochemical device, the electrochemical device is 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 is a lithium nickel cobalt manganese oxide system electrochemical device, the electrochemical device is at an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the interruption period ranges from 1 second to 10 seconds. The duration of the intermittent period ranges from 10 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 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 is a lithium cobalt oxide system electrochemical device, 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 is a lithium cobalt oxide system electrochemical device, 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 SOC of electrochemical devices of different systems.

[0011] In one embodiment of this application, the first parameter of the electrochemical device includes the state of health (SOH) parameter of the electrochemical device and the current total operating time of the electrochemical device. The SOH parameter is related to the state of health (SOH) of the electrochemical device. The response to the first parameter satisfying a first condition includes:

[0012] In response to the fact that the exponent of the current total working time and the current SOH parameter do not satisfy a first linear proportional relationship, the first linear proportional relationship is expressed by the following first expression: y = α × x z +β, where x represents the current total operating time of the electrochemical device, y represents the SOH parameter, z represents the exponential factor, and α and β are constants. The embodiments of this application facilitate accurate determination of the timing for entering intermittent charging operation.

[0013] In one embodiment of this application, the fact that the exponent of the current total working time and the current SOH parameter do not satisfy a first linear proportional relationship includes: the derivative of the first expression for the current SOH parameter and the current total working time is greater than a first threshold. This embodiment of the application facilitates accurate determination of the timing for entering intermittent charging operation.

[0014] A second aspect of this application provides a system including a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, wherein when the processor executes the machine-executable instructions, it implements the steps of the method described in any of the above aspects.

[0015] A third aspect of this application provides an electrochemical device that includes the system described in the second aspect.

[0016] A fourth aspect of this application provides an electronic device, which includes the electrochemical device described in the third aspect.

[0017] This application provides an electrochemical device management method, system, electrochemical device, and electronic device. After acquiring a first parameter of the electrochemical device, in response to the first parameter satisfying a first condition, intermittent charging is performed on the electrochemical device. During the intermittent charging operation, data related to the electrochemical device is acquired. Based on this data, the lithium plating state of charge (SOC) of the electrochemical device is determined. Then, based on the relationship between the lithium plating SOC and the first and second SOCs, the electrochemical device is controlled to stop operating, or at least one of the charging voltage or charging current of the electrochemical device is reduced. This reduces the safety hazards caused by continued use of the electrochemical device after lithium plating, and improves the safety of the electrochemical device during use. Of course, implementing any product or method of this application does not necessarily require achieving all the advantages described above simultaneously. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a flowchart illustrating an electrochemical device management method according to one embodiment of this application;

[0020] Figure 2 This is a schematic diagram of the first curve of one embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the second curve according to one embodiment of this application;

[0022] Figure 4 This is a schematic diagram showing the linear relationship between the SOH parameter and the exponent of the total operating time of the electrochemical device under normal aging in this application.

[0023] Figure 5 This is a schematic diagram of the system structure according to one embodiment of this application;

[0024] Figure 6 This is a schematic diagram of the system structure according to another embodiment of this application. Detailed Implementation

[0025] 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.

[0026] It should be noted that this application uses lithium-ion batteries as an example of electrochemical devices to explain the application, but the electrochemical devices in this application are not limited to lithium-ion batteries.

[0027] This application provides a method for managing an electrochemical device, such as... Figure 1 As shown, the method includes the following steps:

[0028] S101: Obtain the first parameters of the electrochemical device;

[0029] In this embodiment of the application, the parameter acquisition device 501 in the BMS (Battery Management System) can acquire the first parameter of the electrochemical device. The first parameter can be a parameter related to the state of the electrochemical device, such as the SOH (state of health) state of the electrochemical device, the operating time, etc.

[0030] In one example, a sensor in the electrochemical device detects a first parameter of the electrochemical device and then sends the detected first parameter to the battery management system, thereby enabling the battery management system to acquire the first parameter of the electrochemical device. The operation of the process described above is for illustrative purposes only.

[0031] The electrochemical device of this application embodiment may include at least one lithium-ion battery. When multiple lithium-ion batteries are included, these lithium-ion batteries may exist in the electrochemical device in series and / or parallel.

[0032] S102: In response to the first parameter satisfying the first condition, perform intermittent charging operation on the electrochemical device, acquire data related to the electrochemical device during the intermittent charging operation, and determine the lithium plating SOC (State of Charge) of the electrochemical device based on the data related to the electrochemical device.

[0033] In this embodiment, intermittent charging operation can refer to the process of intermittently charging the electrochemical device. Lithium plating state of charge (SOC) can refer to the state of charge associated with the lithium plating state of the electrochemical device. The first parameter can be a parameter related to the state of the electrochemical device. The first condition can be a condition related to the first parameter. For example, when the first parameter includes the current state of charge (SOH) parameter and the current total operating time, the first condition can be that the exponent of the current total operating time does not satisfy a linear proportional relationship with the current SOH parameter.

[0034] In one example, after acquiring the first parameter of the electrochemical device, the parameter acquisition device 501 in the battery management system sends a signal to the lithium plating SOC analysis device 502 in response to the first parameter satisfying a first condition. Upon receiving the signal, the lithium plating SOC analysis device 502 performs intermittent charging on the electrochemical device and performs lithium plating detection and analysis during the intermittent charging operation. It acquires relevant data related to the electrochemical device during the intermittent charging operation and determines the lithium plating SOC of the electrochemical device based on this relevant data. This application embodiment does not impose any particular limitation on the lithium plating SOC analysis device, as long as it can implement intermittent charging operation. Exemplarily, the lithium plating SOC analysis device 502 can be a microcontroller unit (MCU) in the battery management system. The operation of the process described above is for illustrative purposes only.

[0035] Data related to electrochemical devices can refer to data that reflects the state of the electrochemical device, such as, but not limited to, data on the charging voltage, charging current, internal resistance, and state of charge (SOC) of the electrochemical device.

[0036] 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.

[0037] S103: In response to the lithium plating SOC of the electrochemical device being less than or equal to the first SOC threshold, the electrochemical device is controlled to stop operating.

[0038] In this embodiment, the first SOC threshold can be a pre-set threshold. The first SOC threshold can be stored in advance in a storage medium connected to the electrochemical device. The first SOC threshold is generally set based on the SOC corresponding to lithium plating in an electrochemical device sample of the same system as the electrochemical device. For example, the first SOC threshold can be set to the SOC corresponding to lithium plating in the electrochemical device sample. Different first SOC thresholds are typically set for electrochemical devices of different systems. For the same electrochemical device sample, the measured SOC corresponding to lithium plating will also be different at different charging rates and / or ambient temperatures.

[0039] In one example, the lithium plating SOC analysis device 502 performs intermittent charging of the electrochemical device and performs lithium plating detection and analysis during the intermittent charging operation. If the lithium plating SOC is less than or equal to a first SOC threshold, a first signal is sent to the protection device 503. Upon receiving the first signal, the protection device 503 disconnects the electrical connection with the electrochemical device, thereby stopping the electrochemical device from operating. The above-described process is for illustrative purposes only.

[0040] This application embodiment can control the electrochemical device to stop working when the lithium plating SOC of the electrochemical device is less than or equal to a first SOC threshold. Generally speaking, if the lithium plating SOC of the electrochemical device is less than or equal to the first SOC threshold, it indicates that the lithium plating SOC of the electrochemical device has become very low, the aging of the electrochemical device is relatively serious, and it is not suitable for continued use. At this time, the electrical connection with the electrochemical device can be disconnected to stop the electrochemical device from working, reducing the risk of lithium plating due to continued operation and improving the safety of the electrochemical device.

[0041] S104: In response to the lithium plating SOC of the electrochemical device being greater than a first SOC threshold and less than a second SOC threshold, reduce at least one of the charging voltage or charging current of the electrochemical device.

[0042] In this embodiment, the second SOC threshold can be a pre-set threshold. The second SOC threshold can be pre-stored in a storage medium connected to the electrochemical device. The second SOC threshold is generally set based on the first SOC threshold, for example, set to be greater than the first SOC threshold. Different second SOC thresholds are typically set for different electrochemical devices with different systems.

[0043] For example, the lithium plating SOC analysis device 502 performs intermittent charging operation on the electrochemical device and performs lithium plating detection and analysis during the intermittent charging operation. If the lithium plating SOC is greater than a first SOC threshold and less than a second SOC threshold, a second signal is sent to the protection device 503. After receiving the second signal, the protection device 503 reduces the charging voltage of the electrochemical device, or reduces the charging current of the electrochemical device, or simultaneously reduces the charging voltage and charging current of the electrochemical device, thereby reducing the risk of lithium plating occurring due to the electrochemical device continuing to operate at the current voltage and / or current, and improving the safety of the electrochemical device. The operation of the process described above is for illustrative purposes only. In addition, the devices and modules in the battery management system examples in this application are for illustrative purposes only and are not restrictive.

[0044] In one embodiment of this application, the data associated with the electrochemical device includes the state of charge (SOC) and internal resistance of the electrochemical device, and the intermittent charging operation includes multiple charging periods and multiple interruption periods.

[0045] Intermittent charging operation can refer to the process of intermittently charging an electrochemical device. The state of charge (SOC) of lithium plating in the electrochemical device is determined as follows:

[0046] Step A: During the intermittent charging operation, for each of the multiple intermittent periods, obtain the SOC and internal resistance of the electrochemical device during that intermittent period;

[0047] In intermittent charging operations, the internal resistance of the electrochemical device can be determined based on the detected charging voltage and charging current. The BMS can pre-store a voltage-SOC relationship table, which records the SOC of the electrochemical device corresponding to different charging voltages; for example, 4.2V corresponds to 85% SOC, and 4.3V corresponds to 90% SOC. Therefore, the SOC of the electrochemical device can be determined based on the charging voltage and the voltage-SOC relationship table.

[0048] Step B: Based on the multiple SOCs of the obtained electrochemical device and the multiple internal resistances of the electrochemical device corresponding to the multiple SOCs, the first curve is obtained;

[0049] In this embodiment, after obtaining the SOC and internal resistance during multiple intermittent periods of the electrochemical device, multiple data pairs consisting of SOC and internal resistance can be obtained. (Reference) Figure 2 We can use the SOC of the electrochemical device as the abscissa and the internal resistance of the electrochemical device as the ordinate, fill the points represented by these data pairs into the coordinate system, and obtain the first curve after fitting. The first curve represents the mapping curve between the SOC and the internal resistance of the electrochemical device.

[0050] It is understandable that the more intensive the acquisition of SOC 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.

[0051] Step C: Based on the first curve, determine the state of lithium plating (SOC) of the electrochemical device.

[0052] The first curve represents the mapping relationship between the SOC and internal resistance of the electrochemical device. The lithium plating SOC of the electrochemical device can be determined based on the first curve.

[0053] The aforementioned lithium plating SOC may not be measured in real time, but rather obtained from the charging voltage obtained during intermittent charging operations and a voltage-SOC relationship table, which can be pre-stored in the storage medium of the battery management system.

[0054] 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:

[0055] i: Take the first derivative of the first curve to obtain the second curve;

[0056] 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 SOC.

[0057] ii: Determine the SOC corresponding to the point where the slope of the second curve first appears negative as the lithium plating SOC.

[0058] It is understood that the determination of the point where the slope of the second curve first becomes negative can be achieved using techniques known to those skilled in the art, and this application does not limit the scope of the determination. As an example, this application uses the following method to test the point where the slope of the second curve first becomes negative: the slope is calculated based on every two adjacent SOC data points. The points where the slope first becomes negative are denoted as point 1 and point 2. The point with the larger SOC between point 1 and point 2 is the point where the slope of the second curve first becomes negative.

[0059] The second curve represents the rate of change of internal resistance with SOC. 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 3Point 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 shows an abnormal decrease for the first time, indicating that the electrochemical device is showing a tendency to or has already undergone lithium plating at point B. Therefore, the State of Charge (SOC) corresponding to point B can be determined as the lithium plating SOC. Based on the relationship between the lithium plating SOC and the SOC threshold, timely protection of the electrochemical device can be implemented, improving its operational safety. Steps i to ii above are only used to illustrate the order of the steps, not to limit the order of the steps.

[0060] In one implementation, the process of determining the lithium plating state of the electrochemical device based on the first curve can be method 2, which includes:

[0061] i': Take the first derivative of the first curve to obtain the second curve;

[0062] This step is the same as step i in method 1, and will not be repeated here.

[0063] ii': Taking the second derivative of the second curve yields the third curve;

[0064] 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.

[0065] iii': Determine the SOC corresponding to the point where the ordinate of the third curve first appears to be less than zero as the lithium plating SOC.

[0066] If the ordinate of the third curve is less than zero, the SOC corresponding to the first point on the third curve where the ordinate is less than zero is determined as the lithium plating SOC.

[0067] In one implementation, the step of generating the first curve includes:

[0068] Step a: Obtain the first voltage, first current, and first SOC of the electrochemical device at a second time point, and the second voltage and second current of the electrochemical device at a third time point;

[0069] The second moment is the moment when charging stops. The voltage, current, and state of charge (SOC) of the electrochemical device at the second moment can be obtained, namely the first voltage, the first current, and the first SOC, 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.

[0070] Step b: Calculate the voltage and current changes of the electrochemical device during the intermittent period.

[0071] 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.

[0072] 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 SOC as one of the data pairs of the first curve, wherein the data pair is the correspondence between internal resistance and SOC.

[0073] 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.

[0074] Multiple data pairs can be obtained by using the same method described above.

[0075] Step d: Generate the first curve based on the calculated data pairs.

[0076] In this embodiment, the SOC of the electrochemical device is used as the abscissa and the internal resistance of the electrochemical device is used as the ordinate. The points represented by these data pairs are filled in the coordinate system, and the first curve is obtained after fitting.

[0077] Intermittent charging operation can refer to the process of intermittently charging an electrochemical device. In one embodiment, the intermittent charging operation includes multiple charging cycles, each charging cycle including a charging period and an intermittent period. During each charging period, the SOC of the electrochemical device increases by a unit magnitude, that is, the SOC 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.

[0078] 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.

[0079] 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 (SOC) of the electrochemical device reaches a first critical value. It is understood that as intermittent charging proceeds, the SOC of the electrochemical device increases. In this embodiment, intermittent charging can be stopped when the SOC 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%.

[0080] During intermittent charging, the unit amplitude of SOC corresponding to different charging cycles can be different. For example, during the first charging period, the electrochemical device is charged, and after the SOC of the electrochemical device increases by 1%, charging is stopped. After a 5-second interval, the electrochemical device is charged during the second charging period, and after the SOC of the electrochemical device increases by 5%, charging is stopped. After a 5-second interval, the electrochemical device is charged during the third charging period, and after the SOC of the electrochemical device increases by 3%, charging is stopped. This process is repeated until the SOC of the electrochemical device reaches the first critical value.

[0081] 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 (SOC) of the electrochemical device increases by a unit magnitude, at which point charging stops, until a third moment. The moment at which 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.

[0082] For example, if the electrochemical device is charged at time T1 until the state of charge (SOC) of the electrochemical device increases by a unit magnitude, and then the charging stops, the time when the charging stops is time T2; starting from time T2, the electrochemical device is left to stand, and the time when the standing ends is time T3.

[0083] 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 controlling the steps of stopping the electrochemical device or reducing its charging voltage and / or charging current. This helps to reduce the risk of lithium plating in the electrochemical device and extend the service life of the electrochemical device.

[0084] 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:

[0085] 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.

[0086] 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.

[0087] 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.

[0088] This application embodiment sets different unit amplitudes and intermittent periods for different electrochemical devices, enabling more targeted intermittent charging operations for different electrochemical devices, and thus more accurately obtaining the lithium plating SOC of different electrochemical devices.

[0089] 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:

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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%.

[0094] 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.

[0095] 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%.

[0096] 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 thus more accurately obtaining the lithium plating SOC of electrochemical devices in different systems.

[0097] In one embodiment, the first parameter of the electrochemical device includes a state of health (SOH) parameter of the electrochemical device and the current total operating time of the electrochemical device, the SOH parameter being related to the state of health (SOH) of the electrochemical device, and in response to the first parameter satisfying a first condition, including:

[0098] In response to the fact that the exponent of the current total working time does not satisfy the first linear proportional relationship with the current SOH parameter, the first linear proportional relationship is expressed by the following first expression:

[0099] y = α × x z +β

[0100] In the formula, x represents the current total operating time of the electrochemical device, y represents the SOH parameter, z represents the exponential factor, and α and β are constants.

[0101] In this embodiment, the SOH parameter can refer to a parameter related to the SOH of the electrochemical device. It is understood that as the electrochemical device is used, it gradually ages. SOH characterizes the ability of the current electrochemical device to store electrical energy relative to a newer device, and is typically expressed as a percentage representing the state of the electrochemical device from the beginning to the end of its lifespan, used to describe the current performance state of the electrochemical device.

[0102] For example, the parameter acquisition device 501 can acquire the state of equilibrium (SOH) of the electrochemical device. For instance, the SOH sensor detects the current capacity of the electrochemical device, calculates the SOH based on the ratio of the current capacity to the rated capacity, and then sends the SOH to the parameter acquisition device 501. Of course, the aforementioned SOH includes, but is not limited to, SOH within the scope of the field, such as SOH determined based on the capacity of the electrochemical device, SOH determined based on the charge of the electrochemical device, and SOH determined based on the internal resistance of the electrochemical device.

[0103] The current total operating time of an electrochemical device can refer to the total charging and discharging time of the device from the start of its use to the present time.

[0104] For example, the parameter acquisition device 501 can acquire the current total operating time of the electrochemical device, for example, by calculating the current total operating time of the electrochemical device through a timer, and then sending the current total operating time of the electrochemical device to the parameter acquisition device 501.

[0105] In this embodiment, after obtaining the current total working time and the current SOH parameter, it can be determined whether the exponent of the current total working time and the current SOH parameter satisfy the aforementioned first linear proportional relationship. For example, the current total working time and the current SOH parameter can be substituted into the aforementioned first expression to make the determination. (Reference) Figure 4 As the total operating time of the electrochemical device increases, the SOH of the electrochemical device also decreases linearly. Figure 4 In the diagram, the thicker, slanted solid lines are composed of actual sampling points, while the dotted slanted lines are linear fitting lines.

[0106] The inventors of this application have discovered that, under normal aging, the exponent of the current total operating time of an electrochemical device typically follows a first linear proportional relationship with the current state of harmonics (SOH). However, when the electrochemical device malfunctions (e.g., battery failure), this first linear proportional relationship will no longer be satisfied. Based on this, the embodiments of this application can perform intermittent charging operations on the electrochemical device in response to the discontinuation of the first linear proportional relationship between the exponent of the current total operating time and the current SOH, which facilitates accurate determination of the timing for entering intermittent charging operations.

[0107] In one implementation, to more accurately determine when to enter the intermittent charging operation, different z, α, and β values ​​can be set for different electrochemical devices.

[0108] For example, the electrochemical device is a lithium iron phosphate system electrochemical device, where z ranges from 0.45 to 0.75 and α ranges from 0.1 × 10⁻⁶. -3 Up to 10×10 -3 β ranges from 0.9 to 1.05; the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, z ranges from 0.5 to 0.9, and α ranges from 0.2 × 10⁻⁶. -3 Up to 5×10 -3 β ranges from 0.9 to 1.05; the electrochemical device is a lithium cobalt oxide system electrochemical device, z ranges from 0.5 to 0.85, and α ranges from 0.5 × 10⁻⁶. -3 Up to 10×10 -3 β ranges from 0.9 to 1.05.

[0109] The embodiments of this application, by setting different z, α, and β values ​​for different electrochemical devices, can facilitate accurate determination of the timing for entering intermittent charging operation for different electrochemical devices.

[0110] In one implementation, the exponent of the current total working hours does not satisfy the first linear proportional relationship with the current SOH parameter, including:

[0111] The derivative of the first expression under the current SOH parameters and the current total working time is greater than the first threshold.

[0112] In this embodiment, the derivative of the first expression can be taken. When the derivative γ is greater than a first threshold, the electrochemical device is subjected to intermittent charging operation, which is beneficial for accurately determining the timing of entering the intermittent charging operation. The first threshold can be 0.45%, 0.5%, 0.55%, or any value within a certain range.

[0113] In the embodiments of this application, the first SOC threshold and the second SOC threshold may be different based on the characteristics of different electrochemical devices.

[0114] For example, when the electrochemical device is a lithium iron phosphate system electrochemical device, the first SOC threshold is 20% to 60%, for example, 20%, 30%, 40%, 50% or 60%, and the second SOC threshold is 30% to 70%, for example, 30%, 40%, 50%, 60% or 70%.

[0115] When the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the first SOC threshold is 10% to 40%, for example, 10%, 30% or 40%, and the second SOC threshold is 20% to 50%, for example, 20%, 30%, 40% or 50%.

[0116] When the electrochemical device is a lithium cobalt oxide system electrochemical device, the first SOC threshold is 10% to 40%, for example, 10%, 30% or 40%, and the second SOC threshold is 20% to 50%, for example, 20%, 30%, 40% or 50%.

[0117] By setting different first and second SOC thresholds for electrochemical devices of different systems, protection strategies for electrochemical devices of different systems can be optimized more effectively.

[0118] In one embodiment, the step of reducing at least one of the charging voltage or charging current of the electrochemical device includes:

[0119] Step i-1: Reduce the current charging voltage of the electrochemical device by a first reduction rate to a first charging voltage, where the first charging voltage is the updated current charging voltage;

[0120] And / or,

[0121] Step i-2: Reduce the current charging current of the electrochemical device to the first charging current by a third reduction rate, where the first charging current is the updated current charging current.

[0122] The embodiments of this application can reduce the charging voltage and / or charging current of the electrochemical device.

[0123] In one example, when reducing the charging voltage of the electrochemical device, the current charging voltage can be reduced by a first reduction to obtain a first voltage, which is the updated current charging voltage. The first reduction can be from 0.01V to 1V, for example, 0.01V, 0.025V, 0.05V, 0.1V, or 1V.

[0124] In another example, when reducing the charging current of the electrochemical device, the current charging current can be reduced by a third reduction to obtain a first current, which is the updated current charging current. The third reduction can be the product of the battery's rated capacity and a first coefficient, which is between 0.05 and 0.15, for example, 0.05, 0.08, 0.1, 0.12, or 0.15.

[0125] Of course, it is also possible to reduce the charging voltage and charging current of the electrochemical device at the same time.

[0126] In one embodiment, the electrochemical device management method of this application may further include:

[0127] Step ii-1: Reduce the first SOC threshold and the second SOC threshold by the second reduction rate respectively to obtain the updated first SOC threshold and the updated second SOC threshold;

[0128] Step iii-1: In response to the first parameter satisfying the first condition, the electrochemical device is intermittently charged again. During the intermittent charging, relevant data of the electrochemical device is acquired. Based on the relevant data, the lithium plating state of charge of the electrochemical device is determined, and the relationship between the lithium plating SOC and the updated first SOC threshold and the updated second SOC threshold is determined.

[0129] Step iv-1: When the lithium plating SOC is greater than the updated first SOC threshold and less than the updated second SOC threshold, repeat steps i-1 to iii-1 until the difference between the current charging voltage and the initial charging voltage of the electrochemical device is greater than the voltage difference threshold, and generate a prompt message to remind the user to replace the electrochemical device.

[0130] In this embodiment, after reducing the charging voltage, the first SOC threshold and the second SOC threshold can be reduced by a second reduction rate to obtain updated first SOC thresholds and updated second SOC thresholds. Thus, as the battery is used, when intermittent charging is triggered again and lithium plating detection is performed, if the lithium plating SOC of the electrochemical device is greater than the updated first SOC threshold but less than the updated second SOC threshold, the current charging voltage is reduced again by the first reduction rate, and so on. The second reduction rate can be 1% to 10%, for example, 1%, 2.5%, 5%, or 10%. As the charging voltage decreases, when the difference between the current charging voltage and the initial charging voltage of the electrochemical device is greater than the voltage difference threshold, it indicates that the performance of the electrochemical device has significantly degraded. The electrochemical device can be stopped from use, and the user is prompted to replace it, improving the user experience. The aforementioned voltage difference threshold can be 0.01V to 1V, for example, 0.01V, 0.1V, 0.5V, or 1V. The initial charging voltage can be the initial full charge voltage, i.e., the voltage when the electrochemical device is at 100% SOC.

[0131] In one embodiment, the electrochemical device management method of this application may further include:

[0132] Step ii-2: In response to the first parameter satisfying the first condition, the electrochemical device is intermittently charged again. During the intermittent charging, relevant data of the electrochemical device is acquired. Based on the relevant data, the lithium plating state of charge of the electrochemical device is determined, and the relationship between the lithium plating SOC and the first SOC threshold and the second SOC threshold is determined.

[0133] Step iii-2: When the lithium plating SOC is greater than the updated first SOC threshold and less than the updated second SOC threshold, repeat steps i-2 to ii-2 until the difference between the current charging current and the initial charging current of the electrochemical device is greater than the current difference threshold, and generate a prompt message to remind the user to replace the electrochemical device.

[0134] In this embodiment, after reducing the charging current, as the battery is used, when intermittent charging is triggered again and lithium plating detection is performed, if the lithium plating SOC of the electrochemical device is greater than the first SOC threshold but less than the second SOC threshold, the current charging current is reduced again by a third reduction, and so on. As the charging current decreases, when the difference between the current charging current and the initial charging current of the electrochemical device is greater than the current difference threshold, it indicates that the performance of the electrochemical device has degraded significantly. The electrochemical device can then be stopped, and the user is prompted to replace it, thus improving the user experience. The aforementioned current difference threshold is the product of a second coefficient and the rated capacity of the battery, where the second coefficient is between 0.1 and 0.5, for example, 0.1, 0.2, 0.25, 0.4, or 0.5.

[0135] This application provides an electrochemical device management method. After obtaining the first parameter of the electrochemical device, in response to the first parameter satisfying a first condition, the electrochemical device is intermittently charged. During the intermittent charging operation, data related to the electrochemical device is acquired. Based on the data related to the electrochemical device, the lithium plating state of the electrochemical device is determined. Then, based on the relationship between the lithium plating state of the ...

[0136] This application provides a chemical device management method that, after obtaining a first parameter of an electrochemical device, performs intermittent charging on the electrochemical device in response to the first parameter meeting a first condition. During the intermittent charging operation, data related to the electrochemical device is acquired, and the lithium plating state occupancy (SOC) of the electrochemical device is determined based on the relevant data. Then, based on the relationship between the lithium plating SOC and the first and second SOCs, the electrochemical device is controlled to stop working, or at least one of the charging voltage or charging current of the electrochemical device is reduced. This reduces the safety hazards caused by continued use of the electrochemical device after lithium plating and improves the safety of the electrochemical device during use.

[0137] This application also provides a system 500, such as... Figure 5 As shown, the system 500 includes: a parameter acquisition device 501, a lithium plating SOC analysis device 502, and a protection device 503, wherein,

[0138] The parameter acquisition device 501 is used to acquire the first parameter of the electrochemical device.

[0139] The lithium plating SOC analysis device 502 is used to perform intermittent charging operation on the electrochemical device in response to the first parameter satisfying the first condition, acquire relevant data of the electrochemical device during the intermittent charging operation, and determine the lithium plating SOC of the electrochemical device based on the relevant data.

[0140] The protection device 503 is used to control the electrochemical device to stop working in response to the lithium plating SOC of the electrochemical device being less than or equal to a first SOC threshold; or, in response to the lithium plating SOC of the electrochemical device being greater than the first SOC threshold and less than a second SOC threshold, to reduce at least one of the charging voltage or charging current of the electrochemical device.

[0141] The system in this application embodiment can be a battery management system. This application embodiment does not have any particular restrictions on the structure of the parameter acquisition device 501, the lithium plating SOC analysis device 502, and the protection device 503, as long as the corresponding functions can be achieved.

[0142] In one embodiment, 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. The lithium plating SOC analysis device is specifically used for:

[0143] During intermittent charging operation, for each of the multiple intermittent periods, the state of charge (SOC) and internal resistance of the electrochemical device are acquired during that intermittent period. Based on the acquired multiple SOCs of the electrochemical device and the multiple internal resistances corresponding to the multiple SOCs, a first curve is obtained. The first curve is a mapping curve corresponding to the SOC and internal resistance of the electrochemical device.

[0144] Based on the first curve, the state of lithium deposition (SOC) of the electrochemical device was determined.

[0145] 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 SOC of the electrochemical device increases by a unit magnitude.

[0146] 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...

[0147] 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;

[0148] 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;

[0149] The electrochemical device is a lithium cobalt 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.

[0150] In one embodiment, the lithium plating SOC analysis device is specifically used for at least one of the following a) to f):

[0151] 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;

[0152] 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;

[0153] 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;

[0154] 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.

[0155] 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;

[0156] 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.

[0157] In one embodiment, the first parameter of the electrochemical device includes the state of health (SOH) parameter of the electrochemical device and the current total operating time of the electrochemical device. The SOH parameter is related to the state of health (SOH) of the electrochemical device. The lithium plating SOC analysis device is specifically used for:

[0158] In response to the fact that the exponent of the current total operating time and the current SOH parameter do not satisfy the first linear proportional relationship, the electrochemical device is subjected to intermittent charging operation.

[0159] The first linear proportional relationship is expressed by the following first expression:

[0160] y = α × x z +β

[0161] In the formula, x represents the current total operating time of the electrochemical device, y represents the SOH parameter, z represents the exponential factor, and α and β are constants.

[0162] In one implementation, the lithium plating SOC analysis device is specifically used for:

[0163] In response to the derivative of the first expression under the current SOH parameter and the current total operating time being greater than the first threshold, the electrochemical device is subjected to intermittent charging operation.

[0164] The system provided in this application embodiment includes a parameter acquisition device that acquires the first parameter of an electrochemical device. A lithium plating SOC analysis device then performs intermittent charging on the electrochemical device, acquiring data related to the device during this intermittent charging operation. Based on this data, the lithium plating SOC of the electrochemical device is determined. Then, based on the relationship between the lithium plating SOC and a first SOC threshold and a second SOC threshold, a protection device controls the electrochemical device to stop operating, or reduces at least one of the charging voltage or charging current of the electrochemical device. This reduces the safety hazards caused by continued use of the electrochemical device after lithium plating and improves the safety of the electrochemical device during use.

[0165] This application also provides a system, such as Figure 6As shown, the system 600 includes a processor 601 and a machine-readable storage medium 602. The system 600 may also include a charging circuit module 603, an interface 604, a power interface 605, and a rectifier circuit 606. The charging circuit module 603 receives instructions from the processor 601 to perform intermittent charging of the lithium-ion battery. The charging circuit module 603 can also receive instructions from the processor 601 to reduce the voltage / current of the lithium-ion battery 505, or disconnect the electrical connection to the lithium-ion battery to stop its operation. The charging circuit module 603 can also acquire parameters such as the state of harm (SOH) and total operating time of the lithium-ion battery 505 and send these parameters to the processor 601. The interface 604 is used for electrical connection with the lithium-ion battery 505. The power interface 605 is used for connection to an external power source. The rectifier circuit 606 is used for rectifying the input current. The machine-readable storage medium 602 stores machine-executable instructions that can be executed by the processor. When the processor 601 executes the machine-executable instructions, it implements the steps described in any of the above embodiments.

[0166] This application also provides an electrochemical device, including the system 600 described in the above embodiments.

[0167] This application also provides an electronic device, including the electrochemical device described in the above embodiments.

[0168] 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.

[0169] 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.

[0170] For the system / electrochemical device / electronic device 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.

[0171] Preparation Example 1

[0172] Preparation of lithium-ion batteries based on nickel-cobalt-manganese oxide system :

[0173] Preparation of the positive electrode sheet: Lithium nickel cobalt manganese oxide, acetylene black, and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 94:3:3. N-methylpyrrolidone (NMP) was then added as a solvent to prepare a slurry with a solid content of 75%, and the mixture was stirred evenly. The slurry was uniformly coated onto one surface of a 12 μm thick aluminum foil, dried at 90°C, and cold-pressed to obtain a positive electrode sheet with a 100 μm thick positive active material layer. The above steps were repeated on the other surface of the same positive electrode sheet to obtain a positive electrode sheet with positive active material layers coated on both sides. The positive electrode sheet was cut to a size of (74 mm × 867 mm) and tabs were welded on for later use.

[0174] Preparation of the negative electrode sheet: Artificial graphite, acetylene black, styrene-butadiene rubber, and sodium carboxymethyl cellulose (CMC) were mixed in a mass ratio of 96:1:1.5:1.5. Deionized water was then added as a solvent to prepare a slurry with a solid content of 70%, and the mixture was stirred evenly. The slurry was uniformly coated onto one surface of an 8 μm thick copper foil, dried at 110°C, and cold-pressed to obtain a single-sided negative electrode sheet with a 150 μm thick negative active material layer. The coating process was repeated on the other surface of the same negative electrode sheet to obtain a double-sided negative electrode sheet. The negative electrode sheet was cut to a size of 74 mm × 867 mm and tabs were welded on for later use.

[0175] Preparation of the separator: A porous polyethylene (PE) film with a thickness of 15 μm was used as the separator.

[0176] Preparation of electrolyte: In an environment with a water content of less than 10 ppm, non-aqueous organic solvents ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were mixed in a mass ratio of 1:1:1. Then, lithium hexafluorophosphate (LiPF6) was added to the non-aqueous organic solvents, dissolved, and mixed evenly to obtain the electrolyte, wherein the concentration of LiPF6 was 1.15 mol / L.

[0177] Preparation of lithium-ion batteries: The positive electrode, separator, and negative electrode prepared above are stacked in sequence, with the separator positioned between the positive and negative electrode to provide isolation. The electrode assembly is then wound to obtain the electrode assembly. The electrode assembly is placed in an aluminum-plastic film packaging bag and dehydrated at 80°C. A prepared electrolyte is then injected, and the battery undergoes vacuum sealing, settling, formation, and shaping processes to obtain a lithium-ion battery with a rated capacity of 5Ah.

[0178] Preparation Example 2

[0179] Preparation of lithium-ion batteries based on lithium iron phosphate system :

[0180] Preparation of the positive electrode sheet: Lithium iron phosphate, acetylene black, and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 94:3:3. N-methylpyrrolidone (NMP) was then added as a solvent to prepare a slurry with a solid content of 75%, and the mixture was stirred evenly. The slurry was uniformly coated onto one surface of a 12 μm thick aluminum foil, dried at 90°C, and cold-pressed to obtain a positive electrode sheet with a 100 μm thick positive active material layer. The above steps were repeated on the other surface of the same positive electrode sheet to obtain a positive electrode sheet with positive active material layers coated on both sides. The positive electrode sheet was cut to a size of 74 mm × 867 mm and tabs were welded on for later use.

[0181] The preparation methods for the negative electrode, separator, electrolyte, and lithium-ion battery are the same as in Example 1. The rated capacity of the lithium-ion battery is 4 Ah.

[0182] Preparation Example 3

[0183] Preparation of lithium-ion batteries using a hybrid system of lithium cobalt oxide and lithium iron phosphate: :

[0184] Preparation of the positive electrode sheet: Lithium cobalt oxide, lithium iron phosphate, acetylene black, and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 94:3:3 (where the mass ratio of lithium cobalt oxide to lithium iron phosphate was 1:1). N-methylpyrrolidone (NMP) was then added as a solvent to prepare a slurry with a solid content of 75%, and the mixture was stirred evenly. The slurry was uniformly coated onto one surface of a 12 μm thick aluminum foil, dried at 90°C, and cold-pressed to obtain a positive electrode sheet with a 100 μm thick positive active material layer. The above steps were repeated on the other surface of the same positive electrode sheet to obtain a positive electrode sheet with a double-sided coating of positive active material layers. The positive electrode sheet was cut to a size of 74 mm × 867 mm and tabs were welded on for later use.

[0185] The preparation methods for the negative electrode, separator, electrolyte, and electrochemical device are the same as in Preparation Example 1. The rated capacity of the lithium-ion battery is 4.5 Ah.

[0186] Example 1

[0187] Testing of lithium-ion batteries based on nickel-cobalt-manganese oxide system :

[0188] <Detection of Lithium Plating SOC>

[0189] The lithium-ion battery prepared in Preparation Example 1 was subjected to charge-discharge cycles: it was charged at a constant current of 5A to 4.4V, then charged at a constant voltage until the current dropped to 250mA, left to stand for 15 minutes, and then discharged at a constant current of 5A to 2.8V, left to stand for 15 minutes. This charge-discharge cycle was repeated, and the battery's operating time and SOH parameters were obtained. The operating time is the sum of the charging and discharging times. During normal aging of the battery, the first expression is y = (3 × 10⁻⁶). -3 )×x 0.75 The derivative γ of +1 is approximately 0.01%. As the charge-discharge cycle continues, when the derivative γ > 0.5%, the lithium-ion battery is subjected to intermittent charging. After lithium plating detection, the lithium plating SOC is obtained.

[0190] <Lithium-ion battery protection operation>

[0191] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0192] If the lithium plating SOC is greater than the first SOC threshold, the battery continues to undergo charge-discharge cycles. When the lithium-ion battery pressure meets the first condition again, the lithium-ion battery is intermittently charged again until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops charging-discharge cycles. Record the number of charge-discharge cycles, the number of lithium plating detections, the time taken for lithium plating detection, and the final lithium plating SOC of the lithium-ion battery.

[0193] Example 2

[0194] Except for the <protection operation of lithium-ion battery>, which is different from Example 1, everything else is the same as Example 1.

[0195] <Lithium-ion battery protection operation>

[0196] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0197] If the lithium plating SOC is greater than the second SOC threshold, the battery continues to perform charge-discharge cycle operation. When the pressure of the lithium-ion battery meets the first condition again, the lithium-ion battery is intermittently charged again until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops performing charge-discharge cycle operation. The second SOC threshold is 30%.

[0198] If the first SOC threshold < lithium plating SOC ≤ second SOC threshold, the current charging voltage is reduced by 0.025V. In the next lithium plating detection, the first SOC threshold and the second SOC threshold are reduced by 2.5% respectively. The relationship between the lithium plating SOC and the first SOC threshold and the second SOC threshold is then determined, and so on.

[0199] The lithium-ion battery stops charging and discharging when the difference between its current charging voltage and its initial charging voltage exceeds a voltage difference threshold of 0.1V.

[0200] Example 3

[0201] Except for the <protection operation of lithium-ion battery>, which is different from Example 1, everything else is the same as Example 1.

[0202] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0203] If the lithium plating SOC is greater than the second SOC threshold, the battery continues to perform charge-discharge cycle operation. When the pressure of the lithium-ion battery meets the first condition again, the lithium-ion battery is intermittently charged again until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops performing charge-discharge cycle operation. The second SOC threshold is 30%.

[0204] If the first SOC threshold < lithium plating SOC ≤ second SOC threshold, the current charging current voltage is reduced by 0.5A. Then, during the next lithium plating detection, the relationship between the lithium plating SOC and the first and second SOC thresholds is determined again, and so on.

[0205] When the difference between the current charging current and the initial charging current of the lithium-ion battery exceeds a current difference threshold, the lithium-ion battery stops charging and discharging. The current difference threshold is calculated as: a second coefficient × the battery's rated capacity. In this embodiment, the second coefficient is 0.25, and the rated capacity of the lithium-ion battery is 5Ah, so the current difference threshold is 0.25 × 5 = 1.25.

[0206] Example 4

[0207] Except for the lithium-ion battery used in Preparation Example 2, and the difference in charge-discharge cycle operation between the lithium-ion battery and Example 1, the rest is the same as in Example 1.

[0208] Perform charge-discharge cycle operation on the lithium-ion battery: charge at a constant current of 5A to 3.6V, charge at a constant voltage until the current drops to 250mA, let stand for 15min, then discharge at a constant current of 5A to 2.5V, let stand for 15min, and repeat the above charge-discharge cycle operation.

[0209] Example 5

[0210] Except for the lithium-ion battery used in Preparation Example 3, the rest is the same as in Example 1.

[0211] Comparative Example 1

[0212] <Detection of Lithium Plating SOC>

[0213] The lithium-ion battery prepared in Preparation Example 1 was subjected to charge-discharge cycle operation: it was charged at a constant current of 5A to 4.4V, charged at a constant voltage until the current dropped to 250mA, left to stand for 15min, and then discharged at a constant current of 5A to 2.8V, left to stand for 15min. The above charge-discharge cycle operation was repeated, and lithium plating was detected during each charge.

[0214] <Lithium-ion battery protection operation>

[0215] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0216] If the lithium plating SOC is greater than the first SOC threshold, the battery continues to undergo charge-discharge cycles, with lithium plating detection performed during each charge cycle, until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops charging-discharge cycling. The number of charge-discharge cycles, the number of lithium plating detections, the time taken for lithium plating detection, and the final lithium plating SOC of the lithium-ion battery are recorded.

[0217] Comparative Example 2

[0218] Except for the <Lithium-ion Battery Protection Operation>, which differs from Comparative Example 1, everything else is the same as Comparative Example 1.

[0219] <Lithium-ion battery protection operation>

[0220] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0221] If the lithium plating SOC is greater than the second SOC threshold, the battery continues to perform charge-discharge cycle operation. Lithium plating detection is performed during each charge until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops performing charge-discharge cycle operation. The second SOC threshold is 30%.

[0222] If the first SOC threshold < lithium plating SOC ≤ second SOC threshold, the current charging voltage is reduced by 0.025V. In the next lithium plating detection, the first SOC threshold and the second SOC threshold are reduced by 2.5% respectively. The relationship between the lithium plating SOC and the first SOC threshold and the second SOC threshold is then determined, and so on.

[0223] The lithium-ion battery stops charging and discharging when the difference between its current charging voltage and its initial charging voltage exceeds a voltage difference threshold of 0.1V.

[0224] Comparative Example 3

[0225] Except for the <Lithium-ion Battery Protection Operation>, which differs from Comparative Example 1, everything else is the same as Comparative Example 1.

[0226] <Lithium-ion battery protection operation>

[0227] If the lithium plating SOC is less than or equal to the first SOC threshold, the battery stops charging and discharging cycle operations, where the first SOC threshold is 20%.

[0228] If the lithium plating SOC is greater than the second SOC threshold, the battery continues to perform charge-discharge cycle operation. Lithium plating detection is performed during each charge until the lithium plating SOC is less than or equal to the first SOC threshold, at which point the battery stops performing charge-discharge cycle operation. The second SOC threshold is 30%.

[0229] If the first SOC threshold < lithium plating SOC ≤ second SOC threshold, the current charging current voltage is reduced by 0.5A. Then, during the next lithium plating detection, the relationship between the lithium plating SOC and the first and second SOC thresholds is determined again, and so on.

[0230] When the difference between the current charging current and the initial charging current of a lithium-ion battery exceeds a current difference threshold, the lithium-ion battery stops charging and discharging. The current difference threshold is calculated as: a second coefficient × the battery's rated capacity. In this comparative example, the second coefficient is 0.25, and the rated capacity of the lithium-ion battery is 5Ah, so the current difference threshold is 0.25 × 5 = 1.25.

[0231] Comparative Example 4

[0232] Except for using the lithium-ion battery from Preparation Example 2, in the <Detection of Lithium Plating SOC>, the charging voltage was adjusted to 3.6V and the discharging voltage to 2.5V, and the rest was the same as Comparative Example 1.

[0233] Comparative Example 5

[0234] Except for the lithium-ion battery used in Preparation Example 3, the rest is the same as in Comparative Example 1.

[0235] The performance data of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1:

[0236] Example 1 703 1 0.017 28.8％ Example 2 1011 1 0.02 9.4％ Example 3 1023 2 0.03 27.1％ Example 4 4500 3 0.06 24.5％ Example 5 3450 1 0.02 28.2％ Comparative Example 1 622 622 10.4 29.9％ Comparative Example 2 799 799 13.34 9.9％ Comparative Example 3 987 987 16.45 29.9％ Comparative Example 4 4491 4491 73.2 24.9％ Comparative Example 5 3439 3439 56.3 28.7％

[0237] As can be seen from Example 1 and Comparative Example 1, the lithium plating SOC was detected to be basically the same as that of Comparative Example 1, and the total time for lithium plating detection in Example 1 was only 0.16% of that in Comparative Example 1.

[0238] As can be seen from Example 2 and Comparative Example 2, the lithium plating SOC was detected to be basically the same as that of Comparative Example 2, and the total time for lithium plating detection in Example 2 was only 0.15% of that in Comparative Example 2.

[0239] As can be seen from Example 3 and Comparative Example 3, the lithium plating SOC was detected to be basically the same as that of Comparative Example 3, and the total time for lithium plating detection in Example 3 was only 0.18% of that in Comparative Example 3.

[0240] As can be seen from Example 4 and Comparative Example 4, the lithium plating SOC was detected to be basically the same as that of Comparative Example 4, and the total time for lithium plating detection in Example 4 was only 0.08% of that in Comparative Example 4.

[0241] As can be seen from Example 5 and Comparative Example 5, the lithium plating SOC was detected to be basically the same as that of Comparative Example 5, and the total time for lithium plating detection in Example 5 was only 0.04% of that in Comparative Example 5.

[0242] As can be seen, the intermittent charging operation used in the electrochemical device management method of this application shows no significant difference between the detected lithium plating SOC and the SOC detected by the comparative example. This indicates that the method of this application can also effectively detect the lithium plating SOC of lithium-ion batteries, but can significantly reduce the number of lithium plating detections and the total time consumed, reduce invalid detections, improve lithium plating detection efficiency, and thus improve user experience.

[0243] As can be seen from Examples 4 and 5, for lithium-ion batteries of different systems, the electrochemical device management method of this application improves the lithium plating detection efficiency, thereby improving the user experience.

[0244] 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0245] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0246] 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. A method for managing an electrochemical device, wherein, The method includes: Obtain the first parameters of the electrochemical device; In response to the first parameter satisfying the first condition, the electrochemical device is subjected to intermittent charging operation, and data related to the electrochemical device is acquired during the intermittent charging operation. Based on the data related to the electrochemical device, the lithium plating state of the electrochemical device is determined. In response to the lithium plating state occupancy (SOC) of the electrochemical device being less than or equal to a first SOC threshold, the electrochemical device is controlled to stop operating; or In response to the lithium plating state occupancy (SOC) of the electrochemical device being greater than a first SOC threshold and less than a second SOC threshold, at least one of the charging voltage or charging current of the electrochemical device is reduced. 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. 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 includes: During intermittent charging operation, for each of the plurality of intermittent periods, the state of charge (SOC) and internal resistance of the electrochemical device are acquired during that intermittent period. Based on the acquired multiple SOCs of the electrochemical device and the multiple internal resistances corresponding to the multiple SOCs, a first curve is obtained. The first curve is a mapping curve corresponding to the SOC and internal resistance of the electrochemical device. Based on the first curve, the state of lithium deposition (SOC) of the electrochemical device is determined; The first parameter of the electrochemical device includes the state of health (SOH) parameter of the electrochemical device and the current total operating time of the electrochemical device. The SOH parameter is related to the state of health (SOH) of the electrochemical device. The response to the first parameter satisfying the first condition includes: In response to the fact that the exponent of the current total working time and the current SOH parameter do not satisfy a first linear proportional relationship, the first linear proportional relationship is expressed by the following first expression: y=α×x z +β; In the formula, x represents the current total operating time of the electrochemical device, y represents the SOH parameter, z represents the exponential factor, and α and β are constants; Wherein, the exponent of the current total working time and the current SOH parameter do not satisfy the first linear proportional relationship, including: The derivative of the first expression under the current SOH parameter and the current total working time is greater than the first threshold.

2. 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 SOC of the electrochemical device increases by a unit magnitude.

3. The electrochemical device management method according to claim 2, wherein, The electrochemical device includes at least one of a lithium iron phosphate system electrochemical device, a nickel-cobalt-manganese oxide system electrochemical device, or a lithium cobalt oxide system electrochemical device, 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.

4. The electrochemical device management method according to claim 3, wherein, The method satisfies any 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℃ to 10℃, 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.

5. A system 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 1-4.

6. An electrochemical device comprising the system as described in claim 5.

7. An electronic device, wherein, The electronic device includes the electrochemical device as described in claim 6.

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