Electrochemical device management method

Abstract

The embodiment of the present disclosure provides an electrochemical device management method, comprising: determining a lithium precipitation SOC of an electrochemical device; in response to the lithium precipitation SOC being within a preset lithium precipitation SOC range, obtaining first state data in a use process of the electrochemical device, and performing safety state detection on the electrochemical device based on the first state data and the lithium precipitation SOC, wherein the first state data is used to indicate a health state of the electrochemical device, and the safety state detection is used to determine whether the use of the electrochemical device is in a safe state; and determining a use strategy of the electrochemical device based on a result of the safety state detection. The embodiment of the present disclosure can reasonably manage the electrochemical device.

Description

Technical Field

[0001] This disclosure relates to the field of electrochemical technology, and more particularly to a method for managing an electrochemical device. Background Technology

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

[0003] In recent years, with the rapid development of tablet computers, mobile phones, electric vehicles, and energy storage devices, and due to the continuous development of the new energy industry, lithium-ion batteries have become increasingly important, and the market demand for lithium-ion batteries is also increasing. However, during use, lithium-ion batteries often experience lithium plating due to side reactions, impacts, and other reasons, which can easily cause short circuits and pose safety risks, affecting the safety of the battery.

[0004] Therefore, how to better manage lithium-ion batteries to ensure the safety of users has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, embodiments of the present disclosure provide an electrochemical device management method that can reduce the impact of lithium plating on the safety and lifespan of lithium-ion batteries, thereby improving the performance of lithium batteries.

[0006] According to one aspect of the embodiments of this disclosure, an electrochemical device management method is provided, comprising:

[0007] Determine the state of charge (SOC) of lithium plating in the electrochemical device;

[0008] In response to the lithium plating SOC being within a preset lithium plating SOC range, first state data during the use of the electrochemical device is acquired, and the electrochemical device is subjected to safety status detection based on the first state data and the lithium plating SOC. The first state data is used to indicate the health status of the electrochemical device, and the safety status detection is used to determine whether the use of the electrochemical device is in a safe state.

[0009] Based on the results of the safety status detection, the usage strategy of the electrochemical device is determined.

[0010] The electrochemical device management method in this embodiment can determine the lithium plating state occupancy (SOC) of the electrochemical device. Responding to the SOC being within a preset range, and acquiring first state data during the use of the electrochemical device, the method performs safety status detection on the electrochemical device based on the first state data and the SOC. The first state data indicates the health status of the electrochemical device, and the safety status detection determines whether the use of the electrochemical device is in a safe state. Finally, the method determines a usage strategy for the electrochemical device based on the safety status detection results. This allows for reasonable management of the electrochemical device's use when lithium plating occurs, ensuring safe use during lithium plating. Furthermore, different usage strategies are determined for different safety states of the electrochemical device to reduce the impact of lithium plating and maximize the lifespan of the electrochemical device.

[0011] In some optional embodiments, determining the usage strategy of the electrochemical device based on the result of the safety status detection includes: restricting the use of the electrochemical device in response to the electrochemical device not being in a safe state. Therefore, this embodiment of the present disclosure facilitates better assurance of the safety of the electrochemical device during use, thereby ensuring the safety of the user when using the electrochemical device.

[0012] In some optional embodiments, the first state data includes the state of equilibrium (SOH) of the electrochemical device. The safety status detection of the electrochemical device based on the first state data and the state of lithium plating (SOC) includes: determining whether the electrochemical device is in a safe operating state based on the change in the SOC of lithium plating relative to the SOH of the electrochemical device. Therefore, this embodiment of the disclosure combines the change in the SOC of lithium plating relative to the SOH of the electrochemical device, taking both factors into account during analysis. This makes the safety detection results more accurate and allows for a more reasonable and accurate determination of whether the electrochemical device is in a safe operating state, facilitating subsequent management of the electrochemical device based on the result of whether it is in a safe operating state.

[0013] In some optional embodiments, determining whether the electrochemical device is in a safe operating state based on the change in lithium plating SOC relative to the state of oxygen (SOH) of the electrochemical device includes: calculating the safety state parameter COS of the electrochemical device based on the lithium plating SOC and the SOH of the electrochemical device, wherein the COS is the derivative of the lithium plating SOC with respect to the SOH of the electrochemical device; and determining whether the electrochemical device is in a safe operating state based on the COS. Therefore, determining whether the electrochemical device is in a safe operating state in this way in the embodiments of this disclosure makes the safety detection results more accurate and allows for a more reasonable and accurate determination of whether the electrochemical device is in a safe operating state, facilitating subsequent management of the electrochemical device based on the result of whether it is in a safe operating state.

[0014] In some optional embodiments, determining whether the use of the electrochemical device is safe based on the COS includes: determining a first variation curve based on the COS and the SOH of the electrochemical device, wherein the first variation curve represents the change of the COS with the SOH of the electrochemical device; and determining whether the use of the electrochemical device is safe based on the first variation curve. Therefore, this method facilitates accurate determination of whether the use of the electrochemical device is safe in embodiments of this disclosure.

[0015] In some optional embodiments, determining whether the electrochemical device is in a safe operating state based on the first change curve includes: differentiating the first change curve to obtain a second change curve; and determining whether the electrochemical device is in a safe operating state based on the absolute value of the ordinate of the second change curve. Therefore, this method in the embodiments of this disclosure makes the results of safety status detection of the electrochemical device more reasonable, facilitating subsequent management of the electrochemical device based on the results.

[0016] In some optional embodiments, determining whether the electrochemical device is in a safe operating state based on the absolute value of the ordinate of the second change curve includes: if the absolute value is less than a first absolute value threshold, then determining that the electrochemical device is in a safe operating state; and if the absolute value is not less than the first absolute value threshold, then determining that the electrochemical device is not in a safe operating state. Based on this, this method of judgment in the embodiments of this disclosure can reasonably determine whether the electrochemical device is in a safe operating state when lithium plating occurs, so as to better manage the electrochemical device and ensure its safe use when lithium plating occurs.

[0017] In some optional embodiments, restricting the use of the electrochemical device in response to an unsafe condition includes: reducing at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the absolute value being not less than a first absolute value threshold and not greater than a second absolute value threshold, wherein the second absolute value threshold is greater than the first absolute value threshold; and stopping the use of the electrochemical device in response to the absolute value being greater than the second absolute value threshold. Based on this, the embodiments of this disclosure can more rationally manage the electrochemical device, extend its service life, and ensure its safe use.

[0018] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the first absolute threshold value is [2500, 9000]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the first absolute threshold value is [2000, 9000]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the first absolute threshold value is [2000, 9500]. Based on this, different ranges of the first absolute threshold value are set for different systems or types of electrochemical devices in this disclosure to adapt to the safety detection requirements of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results.

[0019] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the second absolute value threshold is [7000, 20000]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second absolute value threshold is [5000, 20000]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the second absolute value threshold is [5500, 20000]. Based on this, different ranges of the second absolute value threshold are set for different systems or types of electrochemical devices in this disclosure to adapt to the safety management needs of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results.

[0020] In some optional embodiments, restricting the use of the electrochemical device in response to an unsafe condition includes: reducing at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the COS being not less than a first COS threshold and not greater than a second COS threshold, wherein the second COS threshold is greater than the first COS threshold; and stopping the use of the electrochemical device in response to the COS being greater than the second COS threshold. Based on this, the embodiments of this disclosure can more rationally manage the electrochemical device, extend its service life, and ensure its safe use.

[0021] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the first COS threshold is [20, 80]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the first COS threshold is [10, 70]; and if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the first COS threshold is [15, 85]. Based on this, different value ranges of the first COS threshold are set for different systems or types of electrochemical devices in this disclosure to adapt to the safety detection requirements of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results.

[0022] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the second COS threshold is [60, 100]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the second COS threshold is [50, 100]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the second COS threshold is [50, 100]. Based on this, different value ranges of the second COS threshold are set for different systems or types of electrochemical devices in this disclosure to adapt to the safety management requirements of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices to achieve better management results.

[0023] In summary, the electrochemical device management scheme in this embodiment can determine the lithium plating state octane (SOC) of the electrochemical device, respond to the lithium plating SOC being within a preset range, and acquire first state data during the use of the electrochemical device. Based on the first state data and the lithium plating SOC, the scheme performs safety status detection on the electrochemical device. The first state data indicates the health status of the electrochemical device, and the safety status detection determines whether the use of the electrochemical device is in a safe state. Finally, the scheme determines the usage strategy of the electrochemical device based on the results of the safety status detection. This allows for reasonable management of the use of the electrochemical device when lithium plating occurs, ensuring safe use when lithium plating occurs. Furthermore, different usage strategies are determined for different safety states of the electrochemical device to reduce the impact of lithium plating and maximize the service life of the electrochemical device. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in this disclosure will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in the embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings.

[0025] Figure 1 This is a flowchart of optional steps in an electrochemical device management method according to an embodiment of the present disclosure.

[0026] Figure 2 This is a graph of a first curve according to an example of an embodiment of the present disclosure.

[0027] Figure 3 This is a graph of a second curve according to an example of an embodiment of the present disclosure.

[0028] Figure 4 This is an optional sub-step flowchart of "determining whether the use of an electrochemical device is safe based on the change in lithium plating SOC relative to the SOH of the electrochemical device according to an embodiment of this disclosure".

[0029] Figure 5 This is a structural block diagram of an electrochemical device management device according to an embodiment of the present disclosure.

[0030] Figure 6 This is a structural diagram of a charging device according to an embodiment of the present disclosure.

[0031] Figure 7 This is a structural diagram of a battery system according to an embodiment of the present disclosure.

[0032] Figure 8The experimental procedure is as described in Experimental Example 1 according to the embodiments of this disclosure.

[0033] Figure 9 The experimental procedure is as described in Experimental Example 2 according to the embodiments of this disclosure.

[0034] Figure 10 The experimental procedure is as described in Experimental Example 3 according to the embodiments of this disclosure. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions in the embodiments of this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this disclosure.

[0036] In the following description, the electrochemical device management method, electronic device, charging device, and storage medium in the embodiments of this disclosure will be specifically described first. Then, some relevant experimental examples and comparative examples of the electrochemical device management method in the embodiments of this disclosure will be given to illustrate the significant advantages of the electrochemical device management method, electronic device, charging device, and storage medium provided in the embodiments of this disclosure compared with the prior art.

[0037] The specific implementation of the embodiments of this disclosure is described below with reference to the accompanying drawings.

[0038] In the embodiments of this disclosure, the electrochemical device 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. It should be noted that although this disclosure uses a lithium-ion battery as an example of an electrochemical device to explain this disclosure, the electrochemical device of this disclosure is not limited to lithium-ion batteries, and may also be, for example, a sodium-ion battery.

[0039] According to one aspect of the embodiments of this disclosure, the embodiments of this disclosure provide an electrochemical device management method, such as... Figure 1 The flowchart shown illustrates that the electrochemical device management method includes the following steps S101, S102, and S103:

[0040] S101: Determine the state of lithium plating (SOC) of the electrochemical device.

[0041] Specifically, in combination Figure 3The block diagram shown illustrates an electrochemical device management device 1000 with the same inventive concept as the electrochemical device management method. The electrochemical device management device 1000 can be an electronic device capable of data processing; for example, it may include a battery management system (BMS) for the electrochemical device, or it may be part of a BMS. This step S101, determining the state of charge (SOC) of the lithium plating in the electrochemical device, can be performed by the first determining device 101 of the electrochemical device management device 1000.

[0042] SOC (State of Charge) is an important parameter of an electrochemical device, which can reflect the remaining charge when the electrochemical device is in use. In the embodiments of this disclosure, the SOC of lithium plating can be the charge state related to the lithium plating state of the electrochemical device.

[0043] This disclosure does not limit the specific steps for determining the lithium plating SOC of the electrochemical device. In some optional embodiments, step S101 may include: performing intermittent charging operation on the electrochemical device, acquiring data related to the electrochemical device during the intermittent charging operation, and determining the lithium plating SOC of the electrochemical device based on the data related to the electrochemical device.

[0044] In this embodiment of the disclosure, by performing intermittent charging operation on the electrochemical device, data related to the electrochemical device can be obtained during the intermittent charging operation. Based on this data, the lithium plating state occupancy (SOC) of the electrochemical device can be determined, which makes it easier to manage the electrochemical device in the future.

[0045] In this embodiment of the disclosure, intermittent charging operation can refer to the process of intermittently charging the electrochemical device. This embodiment of the disclosure does not impose any particular limitation on the charging method in the intermittent charging operation, as long as it achieves the purpose of this embodiment. It can be constant voltage charging, constant current charging, constant current and constant voltage charging, or segmented constant current charging, etc.

[0046] In this embodiment of the disclosure, the data related to the electrochemical device can refer to data that can reflect the state of the electrochemical device, such as, but not limited to, the charging voltage, charging current, internal resistance, and SOC of the electrochemical device.

[0047] Exemplarily, intermittent charging operation can be a process in which the electrochemical device is charged during a first charging period, then charging is stopped, and after a first interruption period, charging continues during a second charging period, and so on, until the 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. Embodiments of this disclosure can stop intermittent charging when the SOC of the electrochemical device reaches the first critical value, thus completing the intermittent charging operation. Embodiments of this disclosure do not impose any particular limitation on the first critical value, as long as the purpose of this disclosure is achieved; for example, the first critical value can be 60%, 70%, 80%, 90%, or 100%.

[0048] In one optional implementation, the intermittent charging operation can specifically be 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.

[0049] Optionally, the intermittent charging operation of this disclosure 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.

[0050] In some optional embodiments, 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 of this disclosure embodiment includes multiple charging periods and multiple interrupted periods. Based on this, the step of "acquiring data associated with the electrochemical device during the intermittent charging operation and determining the lithium plating SOC of the electrochemical device based on the data associated with the electrochemical device" includes steps S1011, S1012, and S1013, specifically:

[0051] S1011: During intermittent charging operation, for each of the multiple intermittent periods, obtain the SOC and internal resistance of the electrochemical device during that intermittent period.

[0052] Optionally, in intermittent charging operation, the internal resistance of the electrochemical device can be determined based on the detected charging voltage and charging current (e.g., calculated using Ohm's law). Optionally, a voltage-SOC relationship table can be pre-stored in the BMS, recording 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.

[0053] S1012: Based on the multiple SOCs of the obtained electrochemical device and the multiple internal resistances of the electrochemical device corresponding to the multiple SOCs, a first curve is obtained. The first curve represents the mapping curve between the SOCs and internal resistances of the electrochemical device.

[0054] In this embodiment of the disclosure, 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, with reference to... 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 in 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.

[0055] In some alternative embodiments, the first curve can be obtained by the following steps a, b, c, and d.

[0056] 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.

[0057] 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.

[0058] Step b: Calculate the voltage and current changes of the electrochemical device during the intermittent period.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Multiple data pairs can be obtained by using the same method described above.

[0063] Step d: Generate the first curve based on the calculated data pairs.

[0064] Using the State of Charge (SOC) of the electrochemical device as the abscissa and the internal resistance of the electrochemical device as the ordinate, the points represented by these data pairs are filled into a coordinate system, and a first curve is obtained after fitting. After obtaining the first curve in this embodiment, the lithium plating SOC of the electrochemical device can be determined through the first curve, thereby determining the SOC at which the electrochemical device tends to plating lithium. This facilitates subsequent management of the electrochemical device and improves its safety in use.

[0065] S1013: Based on the first curve, determine the state of lithium plating (SOC) of the electrochemical device.

[0066] 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. The lithium plating SOC mentioned above may not be measured in real time, but rather obtained from the charging voltage obtained during intermittent charging operation and a voltage-SOC relationship table. This voltage-SOC relationship table can be preset, for example, stored in the storage medium of the electrochemical device management device.

[0067] In an alternative implementation, the process of “determining the lithium plating SOC of the electrochemical device based on the first curve” can be method 1, which includes steps i and ii.

[0068] Step i: Perform a first-order differential on the first curve to obtain the second curve.

[0069] 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.

[0070] Step ii: Determine the SOC corresponding to the point where the slope of the second curve first appears negative as the lithium plating SOC.

[0071] 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 3 Point B is the first point in the second curve where the slope is negative. That is, the flat area of ​​the second curve at point B shows an abnormal decrease for the first time, indicating that the electrochemical device has a tendency to or has already undergone lithium plating at point B. The 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, the electrochemical device can be protected in a timely manner, thereby improving the safety of the electrochemical device.

[0072] In one implementation, the process of "determining the lithium plating SOC of the electrochemical device based on the first curve" can be method 2, which includes steps i, ii', and iii':

[0073] Step i': Perform the first derivative on the first curve to obtain the second curve.

[0074] This step is the same as step i in method 1, and will not be repeated here.

[0075] Step ii': Perform the first derivative of the second curve to obtain the third curve.

[0076] We can also perform a first-order differential on the second curve to obtain the third curve. It can be understood that the third curve is also the second-order differential curve of the first curve.

[0077] Step 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.

[0078] 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.

[0079] Based on this, the optional methods in the embodiments of this disclosure enable a more accurate determination of the lithium plating state of the electrochemical device.

[0080] In some alternative implementations, the intermittent charging operation may include multiple charging cycles, each including a charging period and an intermittent period, during which 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%, 1%, 5%, or 10% SOC during each charging period.

[0081] 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.

[0082] The electrochemical device in this disclosure can be any type or system of electrochemical device. For example, the electrochemical device in this disclosure can include at least one of lithium iron phosphate system electrochemical device, lithium nickel cobalt manganese system electrochemical device, or lithium cobalt oxide system electrochemical device.

[0083] In this disclosure, during intermittent charging operation, different electrochemical devices will correspond to different unit amplitudes and different intermittent periods. In some optional embodiments, specifically:

[0084] If the electrochemical device is a lithium iron phosphate system electrochemical device, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 15 seconds;

[0085] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds.

[0086] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the unit amplitude range is 0.5% to 10%, and the duration of the intermittent period ranges from 1 second to 30 seconds.

[0087] Therefore, by setting different unit amplitudes and intermittent periods for different electrochemical devices, this embodiment of the present disclosure can perform intermittent charging operations on different electrochemical devices in a more targeted manner, and can more accurately obtain the lithium plating SOC of different electrochemical devices.

[0088] In this disclosure, during intermittent charging operation, for the same electrochemical device system, different temperature conditions correspond to different unit amplitudes and different intermittent durations. In some optional embodiments, specifically:

[0089] 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.

[0090] In this embodiment of the present disclosure, 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 the following values ​​of the total mass of the positive electrode active material: 51%, 60%, 70%, 80%, 90%, and 98%.

[0091] 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.

[0092] In this embodiment of the present disclosure, 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%.

[0093] 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.

[0094] In this embodiment of the present disclosure, 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 one of 51%, 60%, 70%, 80%, 90%, or 98% of the total mass of the positive electrode active material.

[0095] This disclosure, by setting different unit amplitudes and intermittent durations for electrochemical devices in the same system at different temperatures, enables more targeted intermittent charging operations for electrochemical devices in different temperature environments, and can more accurately obtain the lithium plating SOC of electrochemical devices in different systems.

[0096] In the embodiments disclosed herein, the lithium plating state occupancy (SOC) of the electrochemical device can also be determined by other means, as long as the requirements are met, and no particular restrictions are imposed here.

[0097] S102: In response to the lithium plating SOC being within the preset lithium plating SOC range, first state data during the use of the electrochemical device is acquired, and the safety status of the electrochemical device is detected based on the first state data and the lithium plating SOC.

[0098] In this embodiment of the disclosure, the first state data is used to indicate the health status of the electrochemical device, and the safety status detection is used to determine whether the use of the electrochemical device is in a safe state.

[0099] Specifically, step S102 can be completed by the detection device 102 of the electrochemical device management device 1000 in this embodiment. In this embodiment, when the determined lithium plating SOC of the electrochemical device is within the preset lithium plating SOC range, it indicates that the electrochemical device has already experienced a certain degree of lithium plating. That is to say, in this embodiment, the electrochemical device is tested for safety status based on the first state data and the lithium plating SOC. This allows for a reasonable determination of whether the use of the electrochemical device is safe, which facilitates the subsequent determination of a reasonable usage strategy for the electrochemical device in step S103, and facilitates more reasonable management of the electrochemical device to ensure its safe use.

[0100] The preset lithium plating SOC range in this embodiment can be set as needed, and this embodiment does not impose any limitations. Since the lithium plating SOC corresponding to lithium plating may differ for different systems and types of electrochemical devices—for example, as mentioned above, the electrochemical devices in this embodiment may include lithium iron phosphate system electrochemical devices, nickel cobalt manganese oxide system electrochemical devices, lithium cobalt oxide system electrochemical devices, etc.—different preset lithium plating SOC ranges are set for different systems and types of electrochemical devices in this embodiment. In some optional embodiments, specifically:

[0101] If the electrochemical device is a lithium iron phosphate system electrochemical device, the upper limit of the preset lithium plating SOC range is [30%, 95%] (for example, values ​​of 30%, 50%, 70%, 80%, 90%, 95%, etc. can be selected from [30%, 95%] according to the actual situation, without restriction here));

[0102] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the upper limit of the preset lithium plating SOC range is [40%, 85%] (for example, values ​​of 40%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc. can be selected from [40%, 85%] according to the actual situation, and no restrictions are imposed here);

[0103] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the upper limit of the preset lithium plating SOC range is [45%, 90%] (for example, values ​​of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90%, etc. can be selected from [45%, 90%] depending on the actual situation, and no restrictions are imposed here).

[0104] Obviously, this allows the electrochemical device management method in the embodiments of this disclosure to adapt to different lithium plating conditions of electrochemical devices with different systems, meet the safety management requirements of different electrochemical devices, and facilitate subsequent targeted management of different systems or types of electrochemical devices to achieve better management results.

[0105] As previously mentioned, the lower the lithium plating SOC in this embodiment, the more severe the lithium plating in the electrochemical device. Therefore, this embodiment provides a range of values ​​for the upper limit of the preset lithium plating SOC range. The lower limit of the preset lithium plating SOC range can be a value lower than the upper limit, such as 0%, 1%, 5%, 10%, etc., and this disclosure does not impose any limitations here. To illustrate this, in an exemplary embodiment, the lower limit is 0%, and the upper limit of the preset lithium plating SOC range is 30%, then the preset lithium plating SOC range is [0%, 30%]. When the lithium plating SOC of the electrochemical device is between 0% and 30%, this embodiment can, in response to the lithium plating SOC being within the preset lithium plating SOC range, acquire first state data during the use of the electrochemical device, and perform safety status detection on the electrochemical device based on the first state data and the lithium plating SOC.

[0106] In this embodiment of the disclosure, the first state data can be any one or more state parameters during battery use that can indicate the health status of the electrochemical device. For example, it can include at least one of the following state parameters: SOH of the electrochemical device, remaining charge of the electrochemical device, number of cycles of the electrochemical device, and operating time of the electrochemical device.

[0107] In some optional embodiments, the first state data includes the SOH of the electrochemical device. Then, the "safety status detection of the electrochemical device based on the first state data and the lithium plating SOC" in step S102 includes: determining whether the use of the electrochemical device is in a safe state based on the change of the lithium plating SOC of the electrochemical device relative to the SOH of the electrochemical device.

[0108] State of health (SOH) is an important parameter during the use of electrochemical devices, measuring their health status. It can be calculated using any reasonable method found in related technologies, and this disclosure does not impose any limitations, as long as the requirements are met. As one example, SOH can be the percentage of the current cycle discharge capacity to the initial capacity of the electrochemical device.

[0109] In this embodiment of the disclosure, by combining the changes in the lithium plating SOC of the electrochemical device with the changes in the SOH of the electrochemical device, both are reasonably considered during the analysis, making the safety detection results more accurate. This allows for a more reasonable and accurate determination of whether the electrochemical device is in a safe state, so that the electrochemical device can be managed subsequently based on the results of whether the electrochemical device is in a safe state.

[0110] This disclosure does not specifically limit the method of determining whether the use of an electrochemical device is safe based on the change in lithium plating SOC relative to SOH. In some optional embodiments, "determining whether the use of an electrochemical device is safe based on the change in lithium plating SOC relative to SOH" may include the following steps S1021 and S1022:

[0111] S1021: Calculate the safety state parameter COS of the electrochemical device based on the lithium plating SOC and the electrochemical device SOH, where COS is the differential value of the lithium plating SOC of the electrochemical device with respect to the SOH of the electrochemical device.

[0112] It is understood that in the embodiments of this disclosure, COS is the differential value of the lithium plating SOC of the electrochemical device with respect to the SOH of the electrochemical device. If the lithium plating SOC is denoted as SOCx, then COS = dSOCx / dSOH. This COS can also be regarded as the rate of change of the lithium plating SOC of the electrochemical device with respect to the SOH of the electrochemical device. Obviously, this safety state parameter COS can accurately reflect the change of the lithium plating SOC of the electrochemical device with respect to the SOH of the electrochemical device.

[0113] S1022: Determine whether the use of the electrochemical device is safe based on COS.

[0114] As mentioned above, the safety status parameter COS can accurately reflect the change of lithium plating SOC relative to the SOH of the electrochemical device. Therefore, in this embodiment of the present disclosure, determining whether the use of the electrochemical device is in a safe state based on COS can make the safety detection results more accurate and more reasonable and accurate in determining whether the electrochemical device is in a safe state, so as to facilitate subsequent management of the electrochemical device based on the result of whether the electrochemical device is in a safe state.

[0115] This disclosure does not limit the specific manner of step S1022, as long as it meets the requirements. In some optional examples, two different alternative implementations are provided to determine whether the use of the electrochemical device is safe based on COS. These two alternative implementations are described in detail below.

[0116] In the first optional implementation (referred to as implementation ① for ease of description below), step S1022 includes the following sub-steps S21 and S22:

[0117] S21: Based on COS and SOH of the electrochemical device, determine the first variation curve, wherein the first variation curve represents the change of COS with the SOH of the electrochemical device.

[0118] Specifically, in this implementation method ①, the first variation curve uses the SOH of the electrochemical device as the abscissa and the COS of the safety state parameter as the ordinate, which can accurately reflect the change of the safety state parameter with SOH.

[0119] When establishing the first variation curve, after obtaining the safety state parameter COS and the SOH of the electrochemical device, multiple data pairs consisting of COS and SOH can be obtained. Each obtained COS and SOH data pair is filled into the coordinate system, and after fitting, the first variation curve can be obtained. It is understood that the more densely the COS and SOH data of the electrochemical device are collected, the more data pairs are obtained, resulting in a more detailed first variation curve. The process of curve fitting using data is well known to those skilled in the art, and this disclosure does not specifically limit it. Optionally, to better utilize the first variation curve, noise reduction, smoothing, and other processing can also be applied to the first variation curve.

[0120] S22: Based on the first change curve, determine whether the use of the electrochemical device is in a safe state.

[0121] Since the first variation curve represents the change of COS with the SOH of the electrochemical device, and COS is the differential value of lithium plating SOC with respect to the SOH of the electrochemical device, the first variation curve is used in conjunction with the embodiments of this disclosure to facilitate accurate determination of whether the use of the electrochemical device is in a safe state.

[0122] In some optional embodiments, step S22 in this disclosure embodiment may include the following sub-steps S221 and S222.

[0123] S221: Differentiate the first curve to obtain the second curve.

[0124] Since the first curve represents the change of COS with the SOH of the electrochemical device, the second curve obtained by differentiating the first curve represents the rate of change of COS with SOH, and its ordinate is dCOS / dSOH.

[0125] S222: Based on the absolute value of the ordinate of the second change curve, determine whether the use of the electrochemical device is in a safe state.

[0126] Based on the absolute value of the vertical axis of the second variation curve, this embodiment of the present disclosure determines the safe use of the electrochemical device in a reasonable manner in combination with actual conditions. This makes the results of safety status detection of the electrochemical device more reasonable, so as to facilitate subsequent management of the electrochemical device based on the results.

[0127] In one optional example of this disclosure, the safety status of the electrochemical device can be determined by thresholding the absolute value of the ordinate of the second change curve (i.e., the absolute value of dCOS / dSOH). Specifically, step S222 may include: if the absolute value is less than a first absolute value threshold, determining that the electrochemical device is in a safe state; and if the absolute value is not less than the first absolute value threshold, determining that the electrochemical device is not in a safe state.

[0128] In this embodiment of the disclosure, when the absolute value of the vertical axis of the second change curve is greater than or equal to the first absolute value threshold, the lithium plating of the electrochemical device has already had a significant impact on its normal and safe use, and therefore the result of the safety status detection can be determined as the use of the electrochemical device being in an unsafe state. When the absolute value of the vertical axis of the second change curve is less than the first absolute value threshold, although the electrochemical device has a certain degree of lithium plating, the lithium plating will not have a significant impact on the normal and safe use of the electrochemical device, and it can continue to be used while continuing to monitor. Therefore, the result of the safety status detection can be determined as the use of the electrochemical device still being in a safe state.

[0129] This method of judgment allows for a reasonable determination of whether an electrochemical device is in a safe operating condition when lithium plating occurs, thus facilitating better management of the device and ensuring its safe operation during lithium plating.

[0130] In this embodiment, the first absolute value threshold can be set as needed and is not limited here. For example, the range of the first absolute value threshold can be [1000, 9000], [2000, 9000], [2500, 9000], [3000, 10000], etc. For specific values, the first absolute value threshold can be 1000, 2000, 2500, 3000, 4000, 6000, 9000, 10000, etc. Furthermore, in this embodiment, different ranges of the first absolute value threshold can be set for different systems or types of electrochemical devices to adapt to the safety detection requirements of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results. For example, as mentioned above, the electrochemical device in the embodiments of this disclosure may include a lithium iron phosphate system electrochemical device, a nickel cobalt manganese oxide system electrochemical device, and a lithium cobalt oxide system electrochemical device. In some optional embodiments, the range of the first absolute value threshold corresponding to each of them may be:

[0131] If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the first absolute value threshold is [2500, 9000];

[0132] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the first absolute value threshold is [2000, 9000];

[0133] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the first absolute value threshold is [2000, 9500].

[0134] Obviously, for a given electrochemical device, when the first absolute threshold value is selected within the corresponding range of values ​​for its respective electrochemical device system, it can meet the safety detection requirements of the corresponding electrochemical device, facilitating targeted management of electrochemical devices of different systems or types. Clearly, for different electrochemical devices, a suitable specific value can be selected from the corresponding range of values ​​for the first absolute threshold value as needed; this is not limited in the embodiments of this disclosure. For example, in some examples, if the electrochemical device is a lithium iron phosphate system electrochemical device, and the range of values ​​for the first absolute threshold value is [2500, 9000], then 3500 can be selected as the first absolute threshold value; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, and the range of values ​​for the first absolute threshold value is [2000, 9000], then 3000 can be selected as the first absolute threshold value; if the electrochemical device is a lithium cobalt oxide system electrochemical device, and the range of values ​​for the first absolute threshold value is [2000, 9500], then 3500 can be selected as the first absolute threshold value.

[0135] In the second optional implementation (referred to as implementation ② for ease of description below), step S1022 includes: if COS is less than a first COS threshold, then determining that the use of the electrochemical device is in a safe state; and if COS is not less than the first COS threshold, then determining that the use of the electrochemical device is not in a safe state.

[0136] Specifically, in this embodiment ②, safety status detection can be performed directly based on the safety status parameter COS. This method can also accurately determine whether the electrochemical device is in a safe operating state. Therefore, either embodiment ① or embodiment ② can be used to detect the safety status of the electrochemical device as needed, and no particular limitation is made in this embodiment. However, it should be noted that, in practical situations, the safety status detection method in embodiment ① is more sensitive than the safety status detection method in embodiment ②.

[0137] In this embodiment of the disclosure, when the safety status parameter COS of the electrochemical device is greater than or equal to the first COS threshold, the lithium plating of the electrochemical device has already significantly affected its normal and safe use, so the result of the safety status detection can be determined that the use of the electrochemical device is not in a safe state. However, when the safety status parameter COS is less than the first COS threshold, although the electrochemical device has a certain degree of lithium plating, the lithium plating will not significantly affect the normal and safe use of the electrochemical device, and it can continue to be used with continued monitoring. Therefore, the result of the safety status detection can be determined that the use of the electrochemical device is still in a safe state.

[0138] This method of judgment allows for a reasonable determination of whether an electrochemical device is in a safe operating condition when lithium plating occurs, thus facilitating better management of the device and ensuring its safe operation during lithium plating.

[0139] In this embodiment, the first COS threshold can be set as needed and is not limited here. For example, the range of the first COS threshold can be [20, 80], [10, 70], [30, 90], [40, 90], etc. For specific values, the first COS threshold can be 20, 30, 50, 60, 70, 80, 90, etc. Furthermore, in this embodiment, different ranges of the first COS threshold can be set for different systems or types of electrochemical devices to adapt to the safety detection requirements of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results. For example, as mentioned above, the electrochemical devices in this embodiment may include lithium iron phosphate system electrochemical devices, nickel cobalt manganese oxide system electrochemical devices, lithium cobalt oxide system electrochemical devices, etc. In some optional embodiments, the range of the first COS threshold corresponding to each can be:

[0140] If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the first COS threshold is [20, 80];

[0141] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the first COS threshold is [10, 70];

[0142] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the first COS threshold is [15, 85].

[0143] Obviously, for a given electrochemical device, when the first COS threshold is selected within the corresponding range of values ​​for its respective electrochemical device system, it can meet the safety detection requirements of the corresponding electrochemical device, facilitating targeted management of electrochemical devices of different systems or types. Clearly, for different electrochemical devices, a suitable specific value can be selected from the corresponding range of first COS threshold values ​​as needed; this is not limited in the embodiments of this disclosure. For example, in some examples, if the electrochemical device is a lithium iron phosphate system electrochemical device, and the range of the first COS threshold is [20, 80], then 30 can be selected as the first COS threshold; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, and the range of the first COS threshold is [10, 70], then 20 can be selected as the first COS threshold; if the electrochemical device is a lithium cobalt oxide system electrochemical device, and the range of the first COS threshold is [15, 85], then 25 can be selected as the first COS threshold.

[0144] S103: Determine the usage strategy for the electrochemical device based on the results of safety status monitoring.

[0145] In this embodiment of the disclosure, step S103 can be completed by the determination device 103 of the electrochemical device 1000. The electrochemical device is managed by the usage strategy determined based on the results of the safety status detection obtained in the aforementioned S101 and S102, so as to ensure the rationality of the management of the use of the electrochemical device.

[0146] The electrochemical device management method in this embodiment can determine the lithium plating state occupancy (SOC) of the electrochemical device. Responding to the SOC being within a preset range, and acquiring first state data during the use of the electrochemical device, the method performs safety status detection on the electrochemical device based on the first state data and the SOC. The first state data indicates the health status of the electrochemical device, and the safety status detection determines whether the use of the electrochemical device is in a safe state. Finally, the method determines a usage strategy for the electrochemical device based on the safety status detection results. This allows for reasonable management of the electrochemical device's use when lithium plating occurs, ensuring safe use during lithium plating. Furthermore, different usage strategies are determined for different safety states of the electrochemical device to reduce the impact of lithium plating and maximize the lifespan of the electrochemical device.

[0147] In this embodiment of the disclosure, the usage strategy determined in step S103 is not subject to any special restrictions, as long as it can meet the requirements. For example, it can be to increase or decrease the charging and discharging voltage, charging and discharging current, etc. No specific restrictions are imposed in this embodiment of the disclosure.

[0148] In some alternative embodiments, step S103 includes: restricting the use of the electrochemical device in response to the fact that the use of the electrochemical device is not in a safe state.

[0149] Since the result of the safety status test is that the electrochemical device is not in a safe state, the lithium plating situation has a significant impact on its normal and safe use. Therefore, the electrochemical device management method in this embodiment adopts a usage strategy that restricts the use of the electrochemical device. This can better ensure the safety of the electrochemical device in use, and thus ensure the safety of the user when using the electrochemical device.

[0150] In this embodiment of the disclosure, restricting the use of electrochemical devices may include reducing at least one of the charging voltage, charging current, discharging voltage, and discharging current of the electrochemical device, or may include other restrictive measures, thereby effectively restricting the use of electrochemical devices by reducing these usage state parameters.

[0151] The preceding text introduced two different optional implementations of step S1022 (i.e., "determining whether the use of the electrochemical device is in a safe state based on COS"), namely implementation ① and implementation ②. The following describes step S103 in the embodiments of this disclosure in further detail with reference to these two optional implementations.

[0152] In some examples of implementation ①, “restricting the use of the electrochemical device in response to the fact that the use of the electrochemical device is not in a safe state” may include: reducing at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the absolute value being not less than a first absolute value threshold and not greater than a second absolute value threshold, wherein the second absolute value threshold is greater than the first absolute value threshold; and stopping the use of the electrochemical device in response to the absolute value being greater than the second absolute value threshold.

[0153] In this embodiment, when the absolute value of the vertical axis of the second variation curve is not less than the first absolute value threshold and not greater than the second absolute value threshold, the electrochemical device, while exhibiting lithium plating, can still maintain a certain level of functionality despite the significant impact of lithium plating on its normal and safe use. Therefore, in this embodiment, at least one of the charging voltage, discharging voltage, charging current, and discharging current can be limited or reduced to ensure the safe use of the electrochemical device and extend its service life. Conversely, when the absolute value of the vertical axis of the second variation curve is greater than the second absolute value threshold, the electrochemical device, while exhibiting lithium plating, can be understood as having a severe impact on its normal and safe use. The functionality of the electrochemical device is difficult to maintain, and continued use will pose a risk of serious consequences such as fire or gas expansion due to severe lithium plating within a short period. Therefore, in this embodiment, a strategy is adopted to stop the use of the electrochemical device at this time to ensure its safe use.

[0154] In embodiment ①, stopping the use of the electrochemical device in this disclosure embodiment may mean stopping the charge-discharge cycle operation of the electrochemical device when the absolute value is greater than the second absolute value threshold, or it may mean turning off the electrochemical device so that it cannot be used, thereby stopping the use of the electrochemical device.

[0155] Obviously, this method in the present disclosure allows for more reasonable management of the electrochemical device, extends its service life, and ensures its safe use.

[0156] In this embodiment, the second absolute value threshold can also be set as needed, and is not limited here. For example, the range of the first absolute value threshold can be [7000, 20000], [5000, 20000], [6000, 20000], [6000, 19000], etc. For specific values, the second absolute value threshold can be 5000, 6000, 7000, 10000, 15000, 19000, 20000, etc. Furthermore, in this embodiment, different ranges of the second absolute value threshold can be set for different systems or types of electrochemical devices to adapt to the safety management needs of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices to achieve better management results. For example, as mentioned above, the electrochemical device in the embodiments of this disclosure may include a lithium iron phosphate system electrochemical device, a nickel-cobalt-manganese oxide system electrochemical device, a lithium cobalt oxide system electrochemical device, etc. In some optional embodiments, the range of the second absolute value threshold corresponding to each of them may be:

[0157] If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the second absolute value threshold is [7000, 20000];

[0158] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second absolute value threshold is [5000, 20000];

[0159] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the second absolute value threshold is [5500, 20000].

[0160] Obviously, for a given electrochemical device, when the second absolute threshold value is taken within the corresponding range of values ​​for its respective electrochemical device system, it can meet the safety management requirements of the corresponding electrochemical device, facilitating targeted management of electrochemical devices of different systems or types. Clearly, for different electrochemical devices, appropriate specific values ​​can also be selected from the corresponding range of values ​​for the second absolute threshold value as needed; this is not limited in the embodiments of this disclosure. For example, in some cases, if the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the second absolute threshold is [7000, 20000], and 11000 can be selected as the second absolute threshold; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second absolute threshold is [5000, 20000], and 10000 can be selected as the second absolute threshold; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the second absolute threshold is [5500, 20000], and 11000 can be selected as the second absolute threshold.

[0161] In some examples of implementation ②, “restricting the use of the electrochemical device in response to the fact that the use of the electrochemical device is not in a safe state” may include: reducing at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the fact that the COS is not less than a first COS threshold and not greater than a second COS threshold, wherein the second COS threshold is greater than the first COS threshold; and stopping the use of the electrochemical device in response to the fact that the COS is greater than the second COS threshold.

[0162] In this embodiment, when the safety state parameter COS of the electrochemical device is not less than the first COS threshold and not greater than the second COS threshold, the electrochemical device, despite exhibiting lithium plating, can still maintain a certain level of functionality, even though the lithium plating has significantly impacted its normal safe use. Therefore, in this embodiment, at least one of the charging voltage, discharging voltage, charging current, and discharging current can be limited or reduced to ensure the safe use of the electrochemical device and extend its service life. Conversely, when the safety state parameter COS is greater than the second COS threshold, the electrochemical device, despite exhibiting lithium plating, can be understood as having severely impacted its normal safe use. The functionality of the electrochemical device is difficult to maintain, and continued use would pose a risk of serious consequences such as fire or gas expansion due to severe lithium plating within a short period. Therefore, in this embodiment, a strategy is adopted to stop the use of the electrochemical device in this situation to ensure its safe use.

[0163] In embodiment ②, stopping the use of the electrochemical device in this disclosure embodiment may mean stopping the charge-discharge cycle operation of the electrochemical device when the absolute value is greater than the second COS threshold, or it may mean turning off the electrochemical device so that it cannot be used, thereby stopping the use of the electrochemical device.

[0164] Obviously, this method in the present disclosure allows for more reasonable management of the electrochemical device, extends its service life, and ensures its safe use.

[0165] In this embodiment, the second COS threshold can be set as needed and is not limited here. For example, the range of the second COS threshold can be [60, 100], [50, 100], [55, 90], [65, 90], etc. For specific values, the second COS threshold can be 50, 55, 60, 65, 80, 90, 95, 100, etc. Furthermore, in this embodiment, different ranges of the second COS threshold can be set for different systems or types of electrochemical devices to adapt to the safety management needs of different electrochemical devices, thereby facilitating targeted management of different systems or types of electrochemical devices and achieving better management results. For example, as mentioned above, the electrochemical devices in this embodiment may include lithium iron phosphate system electrochemical devices, nickel cobalt manganese oxide system electrochemical devices, lithium cobalt oxide system electrochemical devices, etc. In some optional embodiments, the range of the second COS threshold corresponding to each can be:

[0166] If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the second COS threshold is [60, 100];

[0167] If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second COS threshold is [50, 100];

[0168] If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the second COS threshold is [50, 100].

[0169] Obviously, for a given electrochemical device, when the second COS threshold is selected within the corresponding range of values ​​for its respective electrochemical device system, it can meet the safety management requirements of the corresponding electrochemical device, facilitating targeted management of electrochemical devices of different systems or types. Clearly, for different electrochemical devices, a suitable specific value can be selected from the corresponding range of values ​​for the second COS threshold as needed; this is not limited in the embodiments of this disclosure. For example, in some examples, if the electrochemical device is a lithium iron phosphate system electrochemical device, and the range of values ​​for the second COS threshold is [60, 100], then 70 can be selected as the second COS threshold; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, and the range of values ​​for the second COS threshold is [50, 100], then 80 can be selected as the second COS threshold; if the electrochemical device is a lithium cobalt oxide system electrochemical device, and the range of values ​​for the second COS threshold is [50, 100], then 75 can be selected as the second COS threshold.

[0170] Of course, the above parameter values ​​are merely examples or optional embodiments for ease of understanding, and are not intended to limit any aspect of the embodiments disclosed herein.

[0171] Alternatively, if the result of the safety status detection is that the electrochemical device is in a safe state (corresponding to embodiment ①, i.e., the absolute value of the vertical axis of the second change curve is less than the first absolute value threshold; and corresponding to embodiment ②, i.e., COS is less than the first COS threshold), although the electrochemical device exhibits a certain degree of lithium plating, the lithium plating situation will not have a significant impact on the normal and safe use of the electrochemical device. It can continue to be used while continuing to monitor it. Therefore, at this time, the electrochemical device management method does not need to adopt a restriction strategy on the use of the electrochemical device, and the usage status of the electrochemical device can continue to be monitored.

[0172] It is understood that the content described above are all optional implementation methods in the embodiments of this disclosure, and are not intended to limit the embodiments of this disclosure in any way.

[0173] Therefore, the electrochemical device management method in this embodiment can determine the lithium plating state occupancy (SOC) of the electrochemical device, respond to the lithium plating SOC being within a preset lithium plating SOC range, and acquire first state data during the use of the electrochemical device. Based on the first state data and the lithium plating SOC, the method performs safety status detection on the electrochemical device. The first state data is used to indicate the health status of the electrochemical device, and the safety status detection is used to determine whether the use of the electrochemical device is in a safe state. Finally, the method can determine the usage strategy of the electrochemical device based on the results of the safety status detection. This allows for reasonable management of the use of the electrochemical device when lithium plating occurs, ensuring safe use when lithium plating occurs. Furthermore, different usage strategies are determined for different safety states of the electrochemical device to reduce the impact of lithium plating and maximize the service life of the electrochemical device.

[0174] According to another aspect of the embodiments of this disclosure, referring to Figure 5 The present disclosure provides an electrochemical device management device 1000, which includes: a first determining device 101, a detection device 102, and a second determining device 103.

[0175] The first determining device 101 is used to determine the state of lithium plating (SOC) of the electrochemical device;

[0176] The detection device 102 is used to acquire first state data during the use of the electrochemical device in response to the lithium plating SOC being within a preset lithium plating SOC range, and to perform safety status detection on the electrochemical device based on the first state data and the lithium plating SOC, wherein the first state data is used to indicate the health status of the electrochemical device, and the safety status detection is used to determine whether the use of the electrochemical device is in a safe state.

[0177] The second determining device 103 is used to determine the usage strategy of the electrochemical device based on the results of the safety status detection.

[0178] In some alternative embodiments, the second determining device 103 is specifically configured to: restrict the use of the electrochemical device in response to the fact that the use of the electrochemical device is not in a safe state.

[0179] In some alternative embodiments, the first state data includes the state of hydration (SOH) of the electrochemical device, and the detection device 102 is specifically used to determine whether the use of the electrochemical device is in a safe state based on the change in the state of lithium plating (SOC) of the electrochemical device relative to the state of hydration of the electrochemical device.

[0180] In some optional embodiments, the detection device 102 is specifically used to: calculate the safety status parameter COS of the electrochemical device based on the lithium plating SOC and the SOH of the electrochemical device, wherein the COS is the derivative of the lithium plating SOC of the electrochemical device with respect to the SOH of the electrochemical device; and determine whether the use of the electrochemical device is in a safe state based on the COS.

[0181] In some optional embodiments, the detection device 102 is specifically used to: determine a first change curve based on the COS and the SOH of the electrochemical device, wherein the first change curve represents the change of the COS with the SOH of the electrochemical device; and determine whether the use of the electrochemical device is in a safe state based on the first change curve.

[0182] In some optional embodiments, the detection device 102 is specifically used to: differentiate the first change curve to obtain a second change curve; and determine whether the use of the electrochemical device is in a safe state based on the absolute value of the ordinate of the second change curve.

[0183] In some optional embodiments, the detection device 102 is specifically configured to: determine that the use of the electrochemical device is safe if the absolute value is less than a first absolute value threshold; and determine that the use of the electrochemical device is not safe if the absolute value is not less than the first absolute value threshold.

[0184] In some optional embodiments, the second determining device 103 is specifically configured to: restrict the use of the electrochemical device in response to the fact that the use of the electrochemical device is not in a safe state, including: reducing at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the absolute value being not less than the first absolute value threshold and not greater than the second absolute value threshold, wherein the second absolute value threshold is greater than the first absolute value threshold; and stopping the use of the electrochemical device in response to the absolute value being greater than the second absolute value threshold.

[0185] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the first absolute value threshold is [2500, 9000]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the first absolute value threshold is [2000, 9000]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the first absolute value threshold is [2000, 9500].

[0186] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the second absolute value threshold is [7000, 20000]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the second absolute value threshold is [5000, 20000]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the second absolute value threshold is [5500, 20000].

[0187] In some optional embodiments, the detection device 102 is specifically configured to: determine that the use of the electrochemical device is safe if the COS is less than a first COS threshold; and determine that the use of the electrochemical device is not safe if the COS is not less than the first COS threshold.

[0188] In some optional embodiments, the second determining device 103 is specifically configured to: reduce at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device in response to the COS being not less than the first COS threshold and not greater than the second COS threshold, wherein the second COS threshold is greater than the first COS threshold; and stop using the electrochemical device in response to the COS being greater than the second COS threshold.

[0189] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the first COS threshold is [20, 80]; if the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the first COS threshold is [10, 70]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the first COS threshold is [15, 85].

[0190] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the second COS threshold is [60, 100]; if the electrochemical device is a nickel cobalt manganese oxide system electrochemical device, the value range of the second COS threshold is [50, 100]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the second COS threshold is [50, 100].

[0191] In some optional embodiments, the first determining device 101 is specifically used to: 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 state of the electrochemical device based on the data related to the electrochemical device.

[0192] In some optional embodiments, the data associated with 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 first determining device 101 is specifically configured to: during the intermittent charging operation, for each of the multiple interrupted periods, acquire the SOC and internal resistance of the electrochemical device during that interrupted period; based on the acquired multiple SOCs of the electrochemical device and the multiple internal resistances of the electrochemical device corresponding to the multiple SOCs, obtain a first curve, the first curve representing a mapping curve corresponding to the SOC and internal resistance of the electrochemical device; and based on the first curve, determine the lithium plating SOC of the electrochemical device.

[0193] In some optional embodiments, the first determining device 101 is specifically used to: perform a first-order derivative on the first curve to obtain a second curve; and determine the SOC corresponding to the first point on the second curve where the slope is negative as the lithium plating SOC; or, perform a first-order derivative on the first curve to obtain a second curve; perform a first-order derivative on the second curve to obtain a third curve; and determine the SOC corresponding to the first point on the third curve where the ordinate is less than zero as the lithium plating SOC.

[0194] In some alternative embodiments, 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.

[0195] In some optional embodiments, if 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 interruption period ranges from 1 second to 15 seconds; if 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 interruption period ranges from 1 second to 30 seconds; if 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 interruption period ranges from 1 second to 30 seconds.

[0196] In some alternative embodiments, at least one of conditions a) to f) is satisfied:

[0197] 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;

[0198] 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;

[0199] c) The electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the electrochemical device is in an ambient temperature of -10°C to 10°C, the unit amplitude ranges from 0.5% to 10%, and the duration of the intermittent period ranges from 10 seconds to 30 seconds;

[0200] 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;

[0201] 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;

[0202] 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.

[0203] In some optional embodiments, if the electrochemical device is a lithium iron phosphate system electrochemical device, the upper limit of the preset lithium plating SOC range is [30%, 95%]; if the electrochemical device is a nickel cobalt manganese oxide system electrochemical device, the upper limit of the preset lithium plating SOC range is [40%, 85%]; if the electrochemical device is a lithium cobalt oxide system electrochemical device, the upper limit of the preset lithium plating SOC range is [45%, 90%].

[0204] The electrochemical device management device 1000 can be used to implement the corresponding electrochemical device management methods in the foregoing method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here. Furthermore, the functional implementation of each device in the electrochemical device management device 1000 of this disclosure embodiment can be referred to the description of the corresponding part in the foregoing method embodiments, which will also not be repeated here.

[0205] According to another aspect of the present disclosure, the present disclosure provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the electrochemical device management method of any of the preceding claims.

[0206] According to another aspect of the embodiments of this disclosure, embodiments of this disclosure provide a charging device, such as... Figure 6 As shown, the charging device 200 includes a processor 201 and a machine-readable storage medium 202. The charging device 200 may also include a charging circuit module 203, an interface 204, a power interface 205, and a rectifier circuit 206. The charging circuit module 203 receives instructions from the processor 201 to charge the lithium-ion battery 2000 (i.e., the electrochemical device). The charging circuit module 203 can also acquire relevant parameters of the lithium-ion battery 2000 and send them to the processor 201. The interface 204 is electrically connected to the lithium-ion battery 2000 to connect it to the charging device 200. The power interface 205 is connected to an external power source. The rectifier circuit 206 rectifies the input current. The machine-readable storage medium 202 stores machine-executable instructions that can be executed by the processor. When the processor 201 executes the machine-executable instructions, it implements the steps of the electrochemical device management method described in any of the above embodiments.

[0207] According to another aspect of the embodiments of this disclosure, the embodiments of this disclosure also provide a battery system, such as Figure 7As shown, the battery system 300 includes a second processor 301 and a second machine-readable storage medium 302. The battery system 300 may also include a charging circuit module 303, a lithium-ion battery 304 (i.e., an electrochemical device), and a second interface 305. The charging circuit module 303 receives instructions from the second processor 301 to charge the electrochemical device. The charging circuit module 303 can also acquire relevant parameters of the lithium-ion battery 304 (i.e., the electrochemical device) and send them to the second processor 301. The second interface 305 is used to connect to an external charger 400. The external charger 400 provides power. The second machine-readable storage medium 302 stores machine-executable instructions that can be executed by the processor. When the second processor 301 executes the machine-executable instructions, it implements the electrochemical device management method steps described in any of the above embodiments. The external charger 400 may include a first processor 401, a first machine-readable storage medium 402, a first interface 403, and a corresponding rectifier circuit. The external charger may be a commercially available charger; the structure of this embodiment is not specifically limited.

[0208] According to another aspect of the present disclosure, the present disclosure also provides an electronic device that includes the battery system described above.

[0209] 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.

[0210] 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.

[0211] For the embodiments of electrochemical device management device / electronic device / charging device / storage medium / battery system, since they are basically similar to the above-described embodiments of electrochemical device management method, the description is relatively simple. For relevant details, please refer to the description of the above-described embodiments of electrochemical device management method, and will not be repeated here.

[0212] The following detailed descriptions of some preparation examples, experimental examples, and comparative examples in the embodiments of this disclosure will make it easier and clearer to see the significant advantages of the chemical device management method, apparatus, charging device, battery system, electronic device, and computer storage medium provided in the embodiments of this disclosure compared to the prior art. It should be understood that these preparation examples, experimental examples, and comparative examples are not intended to limit the embodiments of this disclosure.

[0213] I. Preparation Example

[0214]

Preparation Example 1

[0215] Preparation of electrochemical devices based on lithium nickel cobalt manganese oxide system:

[0216] 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.

[0217] 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.

[0218] Preparation of the separator: A 15 μm thick porous polyethylene (PE) polymer film was used as the separator.

[0219] 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.

[0220] 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.

[0221]

Preparation Example 2

[0222] Preparation of lithium-ion batteries based on lithium iron phosphate system:

[0223] 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.

[0224] 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.

[0225]

Preparation Example 3

[0226] Preparation of lithium-ion batteries using a hybrid system of lithium cobalt oxide and lithium iron phosphate:

[0227] 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.

[0228] 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.

[0229] II. Experimental Examples

[0230] For ease of explanation, the following experimental examples 1-6 are based on implementation method ② in the aforementioned experimental examples, and experimental example 7 is based on implementation method ① in the aforementioned experimental examples. Furthermore, the aforementioned first COS threshold will be denoted as a and the second COS threshold will be denoted as b.

[0231]

Experiment Example 1

[0232] Testing of lithium-ion batteries based on nickel-cobalt-manganese oxide system:

[0233] <Detection of Lithium Plating SOC>

[0234] 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 4.25V, then charged at a constant voltage until the current dropped to 250mA, allowed to stand for 15 minutes, and then discharged at a constant current of 5A to 2.8V, allowed to stand for 15 minutes. This charge-discharge cycle was repeated, and the state of charge (SOH) of the lithium-ion battery was obtained. SOH represents the percentage of the battery's discharge capacity in the current cycle relative to its initial capacity. Intermittent charging was performed on the lithium-ion battery, and the state of charge (SOC) was obtained after lithium plating detection.

[0235] <Battery COS Calculation>

[0236] Using the lithium plating state of charge (SOC) of the electrochemical device as the ordinate and the current state of oxygen (SOH) data of the electrochemical device as the abscissa, the points represented by these data pairs are filled into a coordinate system. After fitting, a mapping curve corresponding to the lithium plating SOC and SOH is obtained. The first-order derivative of this curve is then performed to obtain the safety state parameter COS value.

[0237] <Lithium-ion battery protection operation>

[0238] If the COS value is greater than the second COS threshold b, the battery (i.e., the electrochemical device) stops charging and discharging cycles, where b is 70. If COS ≤ b, the battery continues charging and discharging cycles until COS > b, at which point the battery stops charging and discharging cycles. Record the number of charging and discharging cycles and the final SOC and COS values ​​of the lithium-ion battery.

[0239] The implementation process of Experiment Example 1 can be seen here. Figure 8 The flowchart is shown below for understanding.

[0240]

Experiment Example 2

[0241] Except for the <Lithium-ion Battery Protection Operation>, which differs from Experimental Example 1, everything else is the same as Experimental Example 1.

[0242] <Lithium-ion battery protection operation>

[0243] If COS > b, the battery stops performing charge / discharge cycles, where b is 70.

[0244] If COS > first COS threshold a, the battery continues to perform charge-discharge cycle operation until COS > b, at which point the battery stops performing charge-discharge cycle operation, where the first COS threshold a is 30;

[0245] If a ≤ COS < b, the current charging voltage will be reduced by 0.025V, and the relationship between COS and a and b will be determined again during the next lithium plating detection, and so on.

[0246] 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.

[0247] The implementation process of Experiment Example 2 can be seen here. Figure 9 The flowchart shown is for reference only, with 0.025V being an optional example in this implementation process.

[0248]

Experiment Example 3

[0249] Except for the <Lithium-ion Battery Protection Operation>, which differs from Experimental Example 1, everything else is the same as Experimental Example 1.

[0250] If COS > b, the battery stops performing charge / discharge cycles, where b is 70.

[0251] If COS > a, the battery continues to perform charge-discharge cycle operation until COS > b, at which point the battery stops performing charge-discharge cycle operation, where the first COS threshold a is 30;

[0252] If a≤COS<b, the current charging current is reduced by 0.5A, and the relationship between COS and a and b is determined again during the next lithium plating detection, and so on.

[0253] 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 α × the battery's rated capacity. In Example 3 of this experiment, α is 0.25, and the rated capacity of the lithium-ion battery is 5Ah. Therefore, the current difference threshold is 0.25 × 5 = 1.25A.

[0254] The implementation process of Experiment Example 3 can be seen here. Figure 10 The flowchart shown is for reference only, where 0.5A is merely an optional example in this implementation process.

[0255]

Experiment Example 4

[0256] 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 Experimental Example 1, the rest are the same as Experimental Example 1.

[0257] 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.

[0258]

Experiment Example 5

[0259] Except for the lithium-ion battery used in Preparation Example 3, the rest is the same as in Experimental Example 1.

[0260]

Experiment Example 6

[0261] Except for <Lithium-ion battery charge-discharge cycle>, which is different from Experimental Example 2, everything else is the same as Experimental Example 2.

[0262] Perform charge-discharge cycle operation on the lithium-ion battery: charge at a constant current of 5A to 4.3V, charge at a constant voltage until the current drops to 250mA, let stand for 15min, then discharge at a constant current of 5A to 2.8V, let stand for 15min, and repeat the above charge-discharge cycle operation.

[0263]

Experiment Example 7

[0264] Except for the differences in <Battery COS Calculation> and <Lithium-ion Battery Protection Operation> compared to Experimental Example 1, the rest are the same as Experimental Example 1.

[0265] <Battery COS Calculation>

[0266] Using the lithium plating state of charge (SOC) of the electrochemical device as the ordinate and the current state of oxygen (SOH) data of the electrochemical device as the abscissa, the points represented by these data pairs are filled into a coordinate system. After fitting, a mapping curve corresponding to the lithium plating SOC and SOH is obtained. The first derivative of this curve yields the safety state parameter COS value. Similarly, using the COS value as the ordinate and the current SOH data of the electrochemical device as the abscissa, the points represented by these data pairs are filled into a coordinate system. After fitting, a mapping curve corresponding to the COS value and SOH (i.e., the first variation curve) is obtained. The first derivative of this curve yields the dCOS / dSOH value.

[0267] <Lithium-ion battery protection operation>

[0268] If the dCOS / dSOH value is greater than the second absolute threshold (10000), the battery stops charging / discharging cycles. If the lithium plating SOC is less than or equal to 10000, the battery continues charging / discharging cycles until the dCOS / dSOH value is greater than 10000, at which point the charging / discharging cycles stop. Record the number of charging / discharging cycles, the final lithium plating SOC, COS, and dCOS / dSOH values ​​of the lithium-ion battery.

[0269] III. Comparative Example

[0270] Comparative Example 1

[0271] <Detection of Lithium Plating SOC>

[0272] 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 4.25V, 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.

[0273] <Lithium-ion battery protection operation>

[0274] 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%.

[0275] 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 and the final lithium plating SOC of the lithium-ion battery are recorded.

[0276] Comparative Example 2

[0277] Except for the <Lithium-ion Battery Protection Operation>, which differs from Comparative Example 1, everything else is the same as Comparative Example 1.

[0278] <Lithium-ion battery protection operation>

[0279] 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%.

[0280] 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%.

[0281] 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.

[0282] 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.

[0283] Comparative Example 3

[0284] Except for the <Lithium-ion Battery Protection Operation>, which differs from Comparative Example 1, everything else is the same as Comparative Example 1.

[0285] <Lithium-ion battery protection operation>

[0286] 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%.

[0287] 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%.

[0288] If the first SOC threshold < lithium plating SOC ≤ second SOC threshold, the current charging current will be 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 will be determined again, and so on.

[0289] When the difference between the current charging current and the initial charging current of the lithium-ion battery exceeds the current difference threshold, the lithium-ion battery stops charging and discharging. The current difference threshold is calculated as α × the battery's rated capacity. In Comparative Example 3, α is 0.25, and the rated capacity of the lithium-ion battery is 5Ah, therefore the current difference threshold is 0.25 × 5 = 1.25A.

[0290] Comparative Example 4

[0291] 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.

[0292] Comparative Example 5

[0293] Except for the lithium-ion battery used in Preparation Example 3, the rest is the same as in Comparative Example 1.

[0294] Comparative Example 6

[0295] Except for <Lithium-ion battery charge-discharge cycle>, which is different from Comparative Example 2, everything else is the same as Comparative Example 2.

[0296] Perform charge-discharge cycle operation on the lithium-ion battery: charge at a constant current of 5A to 4.3V, charge at a constant voltage until the current drops to 250mA, let stand for 15min, then discharge at a constant current of 5A to 2.8V, let stand for 15min, and repeat the above charge-discharge cycle operation.

[0297] IV. Data Summary

[0298] 1. The performance data of Experimental Examples 1 to 6 and Comparative Examples 1 to 6 are shown in Table 1:

[0299] Table 1

[0300]

[0301]

[0302] 2. The performance data for Experiments 1 and 7 are shown in Table 2:

[0303] Table 2

[0304] Group Number of charge-discharge cycles Lithium plating SOC COS value dCOS / dSOH Experimental Example 1 673 18.3％ 89 \ Experimental Example 7 651 19.4％ 69 11531

[0305] V. Results Analysis

[0306] Based on the above experimental examples and comparisons, the following results were obtained:

[0307] Result A: As can be seen from Experimental Examples 1, 4-5 and Comparative Examples 1, 4-5, the detection of lithium plating SOC is basically the same as that of the comparative examples, and the accuracy is similar. However, judging the safety status by COS value can appropriately extend the service life of the electrochemical device and improve the user experience.

[0308] Result B: As can be seen from Experimental Example 2-3 and Comparative Example 2-3, the lithium plating SOC was detected to be basically the same as that in Comparative Example 2. The safety risks were identified in advance by the COS value, which has higher sensitivity. Once the risk was identified, the voltage reduction method was adopted, and the service life of the electrochemical device was effectively extended.

[0309] Result C: As can be seen from Experimental Example 6 and Comparative Example 6, it is difficult to identify the failure risk caused by overcharging based solely on the lithium plating SOC, leading to rapid cell life decay. Before the lithium plating SOC reaches the threshold, the cell capacity has already decreased to below 60%, requiring the experiment to be terminated. However, the COS value can identify this safety risk, allowing for voltage reduction and other measures to address it in the electrochemical device. This significantly reduces the risk of lithium plating during subsequent cycles, effectively extending cell life and ensuring the safety performance of the electrochemical device.

[0310] Result D: As can be seen from Experiment 1 and Experiment 7, the sensitivity of identifying the safety risks of electrochemical devices by dCOS / dSOH is higher (that is, the sensitivity of safety status detection using the aforementioned Implementation Method ① is higher than that of Implementation Method ②). Although the service life will be reduced to a certain extent, the safety performance of the electrochemical device is more guaranteed.

[0311] Based on the above embodiments and comparative examples, multiple sets of repeated experiments were conducted in this disclosure embodiment, and the results obtained were consistent with the above results A, B, C, and D. Therefore, it can be seen that the electrochemical device management scheme in this disclosure embodiment has good application prospects and can achieve good technical effects in practice.

[0312] Therefore, the electrochemical device management scheme in this embodiment can determine the lithium plating state occupancy (SOC) of the electrochemical device, respond to the lithium plating SOC being within a preset lithium plating SOC range, and acquire first state data during the use of the electrochemical device. Based on the first state data and the lithium plating SOC, the scheme performs safety status detection on the electrochemical device. The first state data indicates the health status of the electrochemical device, and the safety status detection determines whether the use of the electrochemical device is in a safe state. Finally, the scheme can determine the usage strategy of the electrochemical device based on the results of the safety status detection. This allows for reasonable management of the use of the electrochemical device when lithium plating occurs, ensuring safe use when lithium plating occurs. Furthermore, different usage strategies are determined for different safety states of the electrochemical device to reduce the impact of lithium plating and maximize the service life of the electrochemical device.

[0313] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0314] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.

[0315] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc., used in this disclosure are only used to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0316] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0317] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0318] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0319] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0320] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for managing an electrochemical device, comprising: Determine the state of charge (SOC) of lithium plating in the electrochemical device; In response to the lithium plating SOC being within a preset lithium plating SOC range, first state data during the use of the electrochemical device is acquired, and the electrochemical device is subjected to safety status detection based on the first state data and the lithium plating SOC. The first state data is used to indicate the health status of the electrochemical device, and the safety status detection is used to determine whether the use of the electrochemical device is in a safe state. Based on the results of the safety status detection, the usage strategy of the electrochemical device is determined; The first state data includes the state of oxygen (SOH) of the electrochemical device, and the safety status detection of the electrochemical device based on the first state data and the state of lithium plating (SOC) includes: Based on the change in the lithium plating state of the electrochemical device relative to the state of oxygen in the electrochemical device, it is determined whether the use of the electrochemical device is in a safe state. The determination of whether the use of the electrochemical device is safe based on the change in the lithium plating state of the electrochemical device relative to the state of oxygen (SOH) of the electrochemical device includes: The safety state parameter COS of the electrochemical device is calculated based on the lithium plating SOC and the state of hydration (SOH) of the electrochemical device, wherein the COS is the differential value of the lithium plating SOC of the electrochemical device with respect to the state of hydration (SOH) of the electrochemical device; Based on the COS, it is determined whether the use of the electrochemical device is in a safe condition.

2. The method according to claim 1, wherein, The process of determining the usage strategy of the electrochemical device based on the results of the safety status detection includes: In response to the fact that the use of the electrochemical device is not in a safe state, the use of the electrochemical device is restricted.

3. The method according to claim 1, wherein, The determination of whether the use of the electrochemical device is safe based on the COS includes: Based on the COS and the SOH of the electrochemical device, a first variation curve is determined, wherein the first variation curve represents the change of the COS with the SOH of the electrochemical device; Based on the first change curve, it is determined whether the use of the electrochemical device is in a safe state.

4. The method according to claim 3, wherein, The step of determining whether the use of the electrochemical device is safe based on the first change curve includes: The second change curve is obtained by differentiating the first change curve. Based on the absolute value of the ordinate of the second change curve, it is determined whether the use of the electrochemical device is in a safe state.

5. The method according to claim 4, wherein, Determining whether the electrochemical device is in a safe operating condition based on the absolute value of the ordinate of the second change curve includes: If the absolute value is less than a first absolute value threshold, then the use of the electrochemical device is determined to be in a safe state; and, If the absolute value is not less than the first absolute value threshold, then it is determined that the use of the electrochemical device is not in a safe state.

6. The method according to claim 5, wherein, The restriction on the use of the electrochemical device in response to an unsafe condition includes: In response to the absolute value being not less than a first absolute value threshold and not greater than a second absolute value threshold, at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device is reduced, wherein the second absolute value threshold is greater than the first absolute value threshold; and, In response to the absolute value being greater than the second absolute value threshold, the use of the electrochemical device is stopped.

7. The method according to claim 5, wherein, If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the first absolute value threshold is [2500, 9000]; If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the first absolute value threshold is [2000, 9000]; If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the first absolute value threshold is [2000, 9500].

8. The method according to claim 6, wherein, If the electrochemical device is a lithium iron phosphate system electrochemical device, the range of the second absolute value threshold is [7000, 20000]; If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second absolute value threshold is [5000, 20000]; If the electrochemical device is a lithium cobalt oxide system electrochemical device, the range of the second absolute value threshold is [5500, 20000].

9. The method according to claim 7, wherein, The restriction on the use of the electrochemical device in response to an unsafe condition includes: In response to the COS being not less than a first COS threshold and not greater than a second COS threshold, at least one of the charging voltage, discharging voltage, charging current, and discharging current of the electrochemical device is reduced, wherein the second COS threshold is greater than the first COS threshold; and, In response to the COS being greater than the second COS threshold, the use of the electrochemical device is stopped.

10. The method according to claim 9, wherein, If the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the first COS threshold is [20, 80]; If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the value range of the first COS threshold is [10, 70]; If the electrochemical device is a lithium cobalt oxide system electrochemical device, the first COS threshold value ranges from [15, 85].

11. The method according to claim 9, wherein, If the electrochemical device is a lithium iron phosphate system electrochemical device, the value range of the second COS threshold is [60, 100]; If the electrochemical device is a lithium nickel cobalt manganese oxide system electrochemical device, the range of the second COS threshold is [50, 100]; If the electrochemical device is a lithium cobalt oxide system electrochemical device, the value range of the second COS threshold is [50, 100].

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