Analyzing method and device for lithium stripping window, computing device, medium and program product

Abstract

The application provides an analysis method and device for a lithium precipitation window, a computing device, a medium and a program product, and belongs to the technical field of batteries. The analysis method for the lithium precipitation window comprises the following steps: charging a to-be-tested battery at a first charging rate to obtain a first charging curve of the to-be-tested battery; charging the to-be-tested battery at a second charging rate to obtain a second charging curve of the to-be-tested battery; determining a lithium precipitation characteristic curve of the to-be-tested battery according to the first charging curve and the second charging curve, wherein the lithium precipitation characteristic curve is used to indicate the lithium precipitation condition of the to-be-tested battery; and determining the lithium precipitation window of the to-be-tested battery at the second charging rate based on the lithium precipitation characteristic curve. The method can accurately determine the lithium precipitation window of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method, apparatus, computing device, medium, and program product for analyzing lithium plating windows. Background Technology

[0002] Energy conservation and emission reduction are key to sustainable social development. Rechargeable batteries, with their ability to store and release energy as needed, are widely used in various electrical devices and energy storage systems, and are an important component in promoting energy transition and sustainable development. For the new energy industry, battery technology is a crucial factor in its development.

[0003] With the rapid development of the new energy industry, increasingly higher demands are being placed on the fast-charging performance of batteries, making the accurate evaluation of battery fast-charging design crucial. Since lithium plating may occur when a battery is charged at a certain rate, leading to a decline in battery performance, the rationality of a battery's fast-charging design can be evaluated by assessing the lithium plating window at different charging rates. However, currently, there is still a lack of methods to accurately detect the lithium plating window. Summary of the Invention

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one objective of this application is to provide an analytical method for lithium plating window, thereby enabling accurate determination of the lithium plating window of a battery.

[0005] An embodiment of the first aspect of this application provides a method for analyzing a lithium plating window, comprising: charging a battery under test at a first charging rate to obtain a first charging curve of the battery under test, the first charging curve indicating the correspondence between voltage and state of charge of the battery under test during charging at the first charging rate; charging the battery under test at a second charging rate to obtain a second charging curve of the battery under test, the second charging curve indicating the correspondence between voltage and state of charge of the battery under test during charging at the second charging rate; determining a lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve, the lithium plating characteristic curve indicating the lithium plating status of the battery under test; and determining a lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve.

[0006] The technical solution of this application embodiment can be applied to a battery with two electrodes. By charging the battery under test at different charging rates, the lithium plating characteristic curve of the battery under test can be normalized according to the two charging curves obtained, reducing the error caused by polarization during charging, thereby accurately obtaining the lithium plating window corresponding to the second charging rate.

[0007] In some embodiments, the first charging rate includes the charging rate at which lithium plating does not occur during the charging of the battery under test to its maximum voltage. By determining the first charging rate as the charging rate at which lithium plating does not occur, a baseline charging curve of the battery under test can be obtained without lithium plating, thereby obtaining a more accurate lithium plating characteristic curve.

[0008] In some embodiments, the first charging rate is set to be greater than 0 and less than or equal to 1.5C. Properly setting the first charging rate can prevent lithium plating from occurring in the battery under test during charging, providing a reasonable first charging curve as a reference charging curve.

[0009] In some embodiments, the first charging rate is set to 0.5C. By precisely designing the first charging rate, the normalized lithium plating characteristic curve can be more accurate and closer to the actual state of the battery.

[0010] In some embodiments, the second charging rate includes the charging rate at which lithium plating occurs during the charging of the battery under test to its maximum voltage. By determining the second charging rate as the charging rate at which lithium plating occurs, a more accurate lithium plating characteristic curve can be obtained based on the charging curve of the battery under test under lithium plating conditions, thereby determining the lithium plating window at that charging rate.

[0011] In some embodiments, determining the lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve includes: for any state of charge (SOC) of the battery under test: determining the first voltage corresponding to the SOC based on the first charging curve; determining the second voltage corresponding to the SOC based on the second charging curve; determining the differential voltage value corresponding to the SOC based on the difference between the second voltage and the first voltage; and determining the lithium plating characteristic curve based on the differential voltage values ​​corresponding to multiple SOCs of the battery under test. Differential processing of the two charging curves based on the corresponding SOCs can reduce the error caused by polarization in the normalized lithium plating characteristic curve, thereby achieving accurate determination of the lithium plating window.

[0012] In some embodiments, determining the lithium plating window of the battery under test at a second charging rate based on the lithium plating characteristic curve includes: differentiating the lithium plating characteristic curve to obtain a lithium plating differential curve; and determining the lithium plating window based on the lithium plating differential curve. Differentiating the lithium plating characteristic curve yields a lithium plating differential curve that shows the state of charge at which lithium plating begins in the battery under test, thereby allowing for the determination of an accurate lithium plating window.

[0013] In some embodiments, determining the lithium plating window based on the lithium plating differential curve includes: determining the initial state of charge (SOC) of lithium plating based on the SOC corresponding to the valley point of the lithium plating differential curve and the lithium plating characteristic curve. The initial SOC indicates the SOC of the battery under test at which lithium plating occurs at the second charging rate. The valley point of the lithium plating differential curve reflects the SOC of the battery under test at which lithium plating begins. By combining this with the lithium plating characteristic curve, an accurate SOC at which lithium plating begins can be obtained.

[0014] In some embodiments, the analysis method further includes determining a charging strategy for the battery under test based on the lithium plating window of the battery under test at a second charging rate. Since batteries have different lithium plating windows at different charging rates, a charging strategy for the battery can be determined based on the lithium plating window of the battery under test at a specific charging rate, thereby improving the charging performance of the battery without causing lithium plating.

[0015] In some embodiments, determining the charging strategy for the battery under test based on the lithium plating window of the battery under test at a second charging rate includes: charging the battery under test at a second charging rate in response to the battery under test not reaching a predetermined state of charge, wherein the predetermined state of charge is less than or equal to the lithium plating initiation state of charge. Charging the battery under test at a specific charging rate until the battery under test reaches the predetermined state of charge, since the predetermined state of charge is less than or equal to the lithium plating initiation state of charge, means that lithium plating has not yet begun to occur when the predetermined state of charge is reached, thereby reducing the risk of lithium plating during charging and mitigating the impact of lithium plating on battery performance.

[0016] In some embodiments, the predetermined state of charge is set to be greater than or equal to 70% and less than or equal to 90% of the initial state of charge at which lithium plating begins. By reasonably setting the predetermined state of charge, the charging efficiency can be improved while further reducing the risk of lithium plating in the battery, thus enhancing the charging effect.

[0017] In some embodiments, the predetermined state of charge is set to 72% of the lithium plating initiation state of charge. By reasonably setting the predetermined state of charge, the resulting charging strategy can be applied to the battery mass production process, thereby achieving reasonable control of the mass production process.

[0018] In some embodiments, determining the charging strategy for the battery under test based on the lithium plating window of the battery under test at the second charging rate further includes: charging the battery under test at a third charging rate, which is lower than the second charging rate, in response to the battery under test reaching a predetermined state of charge. Since a smaller charging rate results in a larger initial state of charge for lithium plating, the charging rate can be reduced to continue charging the battery under test when the battery under test reaches the predetermined state of charge, thus achieving reasonable control of the charging process.

[0019] In some embodiments, the analysis method further includes: determining whether the battery under test meets the preset usage conditions based on the lithium plating window of the battery under test at a second charging rate. By using the lithium plating window of the battery under test, it is possible to determine whether the performance of the battery under test is normal, reducing the risk of abnormal batteries entering subsequent usage stages.

[0020] In some embodiments, determining whether a battery under test meets preset usage conditions based on its lithium plating window at a second charging rate includes: determining that the battery under test does not meet preset usage conditions in response to the battery under test having a lithium plating initiation state of charge less than a preset threshold state of charge. Based on whether the battery under test has a lithium plating initiation state of charge less than a threshold state of charge, accurate identification and interception of abnormal batteries can be achieved.

[0021] In some embodiments, determining the lithium plating window of the battery under test at a second charging rate based on the lithium plating characteristic curve further includes: after differentiating the lithium plating characteristic curve to obtain a lithium plating differential curve, performing noise reduction processing on the lithium plating differential curve. By performing noise reduction processing on the curve, the error introduced by noise during the analysis process can be reduced, and the accuracy of the analysis process can be improved.

[0022] In some embodiments, the analysis method further includes: determining the battery capacity of the battery under test; determining the charging capacity of the battery under test; and determining the state of charge (SOC) of the battery under test based on the charging capacity and battery capacity. By determining the SOC of the battery under test, an accurate charging curve can be obtained, leading to more accurate analysis results.

[0023] In some embodiments, determining the battery capacity of the battery under test includes: charging the battery under test at a fourth charging rate using a constant current; charging the battery under test at a constant voltage using a first threshold voltage in response to the battery voltage reaching a first threshold voltage; stopping charging the battery under test in response to the battery charging current reaching a first threshold current; discharging the battery under test at a first discharge rate using a constant current; determining a first discharge capacity of the battery under test in response to the battery voltage reaching a second threshold voltage, the first discharge capacity indicating the amount of electricity discharged by the battery under test during the constant current discharge at the first discharge rate; discharging the battery under test at a second discharge rate using a constant current; determining a second discharge capacity of the battery under test in response to the battery voltage reaching a third threshold voltage, the second discharge capacity indicating the amount of electricity discharged by the battery under test during the constant current discharge at the second discharge rate; and determining the sum of the first discharge capacity and the second discharge capacity as the battery capacity of the battery under test. Accurate determination of the battery capacity of the battery under test provides a more accurate state of charge and improves the accuracy of the analysis process.

[0024] In some embodiments, the analysis method further includes: after charging the battery under test at a first charging rate and / or a second charging rate: stopping charging the battery under test in response to the battery under test voltage reaching a fourth threshold voltage; performing constant current discharge on the battery under test at a third discharging rate; performing constant current discharge on the battery under test at a fourth discharging rate in response to the battery under test voltage reaching a fifth threshold voltage; and stopping discharging the battery under test in response to the battery under test voltage reaching a sixth threshold voltage. Continuing to discharge the battery under test after charging allows for cyclic testing of charging curves at multiple different charging rates, improving testing efficiency.

[0025] An embodiment of the second aspect of this application provides an analysis apparatus for a lithium plating window, comprising: a first module for charging a battery under test at a first charging rate to obtain a first charging curve of the battery under test, the first charging curve indicating the correspondence between voltage and state of charge of the battery under test during charging at the first charging rate; a second module for charging the battery under test at a second charging rate to obtain a second charging curve of the battery under test, the second charging curve indicating the correspondence between voltage and state of charge of the battery under test during charging at the second charging rate; a third module for determining a lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve, the lithium plating characteristic curve indicating the lithium plating status of the battery under test; and a fourth module for determining the lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve.

[0026] An embodiment of the third aspect of this application provides a computing device, including: at least one processor; and at least one memory communicatively connected to the at least one processor, the at least one memory storing instructions that, when executed individually or jointly by the at least one processor, cause the computing device to perform the analysis method described in the above embodiments.

[0027] An embodiment of the fourth aspect of this application provides a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the analysis method described in the above embodiments.

[0028] An embodiment of the fifth aspect of this application provides a computer program product including instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the analysis method described above.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0030] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0031] Figure 1 This is a flowchart illustrating the analysis method of the lithium plating window in some embodiments of this application;

[0032] Figure 2 This is a schematic diagram of charging curves for some embodiments of this application;

[0033] Figure 3 This is a flowchart illustrating the process of determining lithium plating characteristic curves in some embodiments of this application;

[0034] Figure 4 This is a schematic diagram of lithium plating characteristic curves for some embodiments of this application;

[0035] Figure 5 This is a flowchart illustrating the process of determining the lithium plating window in some embodiments of this application;

[0036] Figure 6 This is a schematic diagram of lithium plating differential curves for some embodiments of this application;

[0037] Figure 7This is a schematic diagram of lithium plating differential curves corresponding to different charging rates in some embodiments of this application;

[0038] Figure 8 This is a schematic diagram of the process for determining the state of charge in some embodiments of this application;

[0039] Figure 9 This is a schematic diagram illustrating the process of determining battery capacity in some embodiments of this application;

[0040] Figure 10 This is a schematic diagram of the charge-discharge cycle process of the battery under test in some embodiments of this application;

[0041] Figure 11 This is a schematic block diagram of an analysis apparatus for a lithium plating window according to some embodiments of this application;

[0042] Figure 12 This is a schematic block diagram of a computing device according to some embodiments of this application. Detailed Implementation

[0043] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0045] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0048] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0049] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0050] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0051] Currently, the application of rechargeable batteries is becoming increasingly widespread, judging from market trends. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in various electronic devices, such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application areas of rechargeable batteries continue to expand, the market demand is also constantly increasing.

[0052] With the rapid development of the new energy industry, increasingly higher demands are being placed on the fast-charging performance of batteries, making accurate evaluation of fast-charging design crucial. To improve charging efficiency, a higher charging rate is typically preferred. However, when a battery is charged at a certain rate, lithium plating may occur, leading to a decline in battery performance. Taking lithium-ion batteries as an example, under normal charging conditions, only phase changes involving the lithium intercalation state of the material occur (e.g., in lithium iron phosphate (LFP) batteries, the LiCl2 and LiC6 phases appear sequentially during charging). However, at a certain charging rate, lithium plating may occur during the charging process (e.g., when the battery reaches a certain threshold charge level), where lithium metal is deposited on the electrode surface. Lithium plating will have irreversible effects on battery performance, such as decreased battery capacity, increased internal resistance, and accelerated self-discharge rate, potentially leading to low battery voltage.

[0053] The timing of lithium plating in a battery varies depending on the charging rate used; in other words, the lithium plating window changes with the charging rate. Therefore, to reduce the risk of lithium plating during charging and improve battery charging design, it is necessary to accurately determine the lithium plating window corresponding to a specific charging rate, thereby enabling a more rational charging design based on this window.

[0054] However, currently, there is still a lack of methods to accurately detect the lithium plating window. Especially for batteries with two electrodes, it is difficult to obtain an accurate lithium plating window because testing equipment for three-electrode batteries cannot be used.

[0055] To obtain an accurate lithium plating window, the battery can be charged at different charging rates, and the charging curves at different charging rates can be determined. The obtained charging curves are then normalized to obtain the lithium plating characteristic curve of the battery, and the lithium plating window of the battery can be determined based on the lithium plating characteristic curve.

[0056] This analytical method can be applied to different types of batteries, such as traditional stacked batteries, pouch batteries, prismatic batteries, and cylindrical batteries. By normalizing the two charging curves to obtain the lithium plating characteristic curve, this method can reduce the error caused by polarization during charging, thereby accurately obtaining the lithium plating window corresponding to a specific charging rate.

[0057] The lithium plating window analysis method disclosed in this application can be used, but is not limited to, in the testing of batteries used in electrical devices or energy storage devices such as vehicles, ships, or aircraft. Using the analysis method with the lithium plating window disclosed in this application is advantageous for obtaining the lithium plating window at a specific charging rate, thus reducing the risk of lithium plating during battery charging.

[0058] This application provides a method for analyzing lithium plating windows. (See reference...) Figure 1 The analytical method 100 for lithium plating window includes steps 110 to 140.

[0059] Step 110: Charge the battery under test at a first charging rate to obtain a first charging curve for the battery under test. The first charging curve indicates the relationship between voltage and state of charge of the battery under test during the charging process at the first charging rate.

[0060] Step 120: Charge the battery under test at a second charging rate to obtain a second charging curve for the battery under test. The second charging curve indicates the relationship between voltage and state of charge of the battery under test during the charging process at the second charging rate.

[0061] Step 130: Determine the lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve. The lithium plating characteristic curve is used to indicate the lithium plating status of the battery under test.

[0062] Step 140: Based on the lithium plating characteristic curve, determine the lithium plating window of the battery under test at the second charging rate.

[0063] In embodiments of this application, the term "battery" can encompass a single battery cell, or a series, parallel, or hybrid configuration of multiple battery cells (e.g., a battery module). In one example, a battery may include a lithium-ion battery. The term "lithium plating window" can indicate the stage during which lithium plating occurs in the battery during charging and discharging. In some embodiments, the "lithium plating window" can be represented by the battery's voltage range, potential range, state of charge (SOC) range, etc., indicating that lithium plating occurs during a certain voltage range, potential range, or SOC range in the charging and discharging process. Hereinafter, the lithium plating window will be described using the SOC range as an example. The battery's SOC indicates the ratio of its current capacity to its fully charged capacity (also referred to as battery capacity), typically expressed as a percentage.

[0064] In steps 110 and 120, the battery under test can be charged at different charging rates. The charging rate (and / or discharging rate) of the battery can be equal to the ratio between the charging current (and / or discharging current) and the battery's rated capacity. C is the unit of charging rate (and / or discharging rate). For example, 1C can represent the current intensity when the battery is fully discharged in one hour. If a battery nominally rated at 2200 mA·h is discharged completely in one hour at a 1C discharge rate, the discharge current is 2200 mA.

[0065] During the charging process, the voltage and state of charge of the battery under test can be sampled to obtain a charging curve corresponding to a certain charging rate. Figure 2 A set of examples illustrating charging curves is shown. For example... Figure 2 As shown, for different charging rates (e.g.) Figure 2 The charging rates (0.5C, 1.0C, 1.5C, 2.0C, 2.5C, 3.0C, 3.5C, 4.0C, etc.) can be used to determine the correspondence between the voltage and state of charge of the battery under test at that charging rate, thus obtaining the charging curve corresponding to that charging rate. It should be understood that... Figure 2 The choice of charging rate in this example is merely one example; the first and second charging rates can be set to other charging rates, and this application does not limit this.

[0066] After obtaining the first and second charging curves, the lithium plating characteristic curve of the battery under test can be further determined based on these two curves. For different charging rates, corresponding lithium plating characteristic curves will also be obtained. The lithium plating characteristic curve can be used to represent the lithium plating status of the battery under test and can be used in the process of determining the lithium plating window. In step 140, the lithium plating window corresponding to the second charging rate can be determined based on the obtained lithium plating characteristic curve. The specific process of determining the lithium plating characteristic curve and the lithium plating window will be detailed below.

[0067] The above analysis method can be applied to batteries with two electrodes. By charging the battery under test at different charging rates, the lithium plating characteristic curve of the battery under test can be normalized based on the two charging curves obtained, reducing the error caused by polarization during charging, and thus accurately obtaining the lithium plating window corresponding to the second charging rate.

[0068] According to some embodiments of this application, the first charging rate includes the charging rate at which the battery under test does not exhibit lithium plating during the charging process to its maximum voltage.

[0069] In embodiments of this application, the maximum voltage of the battery under test may indicate the maximum voltage that the battery under test can output or the maximum voltage that the battery under test can reach during charging. In some embodiments, the maximum voltage may also be expressed as the rated voltage of the battery under test.

[0070] During battery charging, the probability of lithium plating increases with the charging rate. When charging at a lower rate, lithium plating may not occur during the process of charging to the maximum voltage. However, when charging at a higher rate, lithium plating will occur during the process of charging to the maximum voltage. Furthermore, as the charging rate increases, lithium plating will occur earlier and earlier, and the state of charge at the time of plating will be lower and lower.

[0071] To obtain an accurate lithium plating characteristic curve, the first charging curve of the battery under test without lithium plating can be used as a benchmark. In the first charging curve, since lithium plating is not present, the battery's voltage and state of charge change normally during charging and are not affected by lithium plating.

[0072] In some embodiments, testing can be performed on a specific type of battery to obtain a charging rate range in which lithium plating does not occur. The first charging rate can be selected from this charging rate range.

[0073] By setting the first charging rate as the charging rate that does not result in lithium plating, a baseline charging curve of the battery under test can be obtained without lithium plating, thus yielding a more accurate lithium plating characteristic curve.

[0074] According to some embodiments of this application, the first charging rate is set to be greater than 0 and less than or equal to 1.5C.

[0075] As mentioned above, under normal circumstances, the charging rate range in which the battery under test will not exhibit lithium plating can include a range greater than 0 and less than or equal to 1.5C. The first charging rate can be selected from this charging rate range.

[0076] Setting a reasonable first charging rate can prevent lithium plating from occurring in the battery under test during charging, and provide a reasonable first charging curve as a reference charging curve.

[0077] According to some embodiments of this application, the first charging rate is set to 0.5C.

[0078] During the analysis of the lithium plating window, the battery under test can be charged at a first charging rate of 0.5C to obtain the corresponding charging curve.

[0079] By precisely designing the first charging rate, the normalized lithium plating characteristic curve can be more accurate and closer to the actual situation of the battery.

[0080] According to some embodiments of this application, the second charging rate includes the charging rate at which lithium plating occurs during the charging of the battery under test to its maximum voltage.

[0081] As mentioned above, lithium plating may occur in batteries as the charging rate increases. To obtain an accurate lithium plating characteristic curve, the first charging curve obtained without lithium plating can be used as a benchmark, and the second charging curve obtained with lithium plating is compared with the first charging curve. In the first charging curve, both voltage and state of charge change normally. However, in the second charging curve, due to the influence of lithium plating, the relationship between voltage and state of charge will show abnormalities. By comparing the second charging curve and the first charging curve and normalizing the results, the lithium plating characteristic curve can be obtained, which can fully reflect the lithium plating situation of the battery and thus determine the lithium plating window of the battery.

[0082] In some embodiments, testing can be performed on a specific type of battery to determine the charging rate range in which lithium plating occurs. A second charging rate can then be selected from this charging rate range. Figure 2 In the example shown, the second charging rate can be set to greater than or equal to 2.0C.

[0083] By determining the second charging rate as the charging rate at which lithium plating occurs, a more accurate lithium plating characteristic curve can be obtained based on the charging curve of the battery under test when lithium plating occurs, thereby determining the lithium plating window at that charging rate.

[0084] According to some embodiments of this application, reference is made to Figure 3 Step 130 includes steps 310 to 340.

[0085] For any state of charge of the battery under test:

[0086] Step 310: Determine the first voltage corresponding to the state of charge based on the first charging curve.

[0087] Step 320: Determine the second voltage corresponding to the state of charge based on the second charging curve.

[0088] Step 330: Determine the differential voltage value corresponding to the state of charge based on the difference between the second voltage and the first voltage.

[0089] Step 340: Determine the lithium plating characteristic curve based on the differential voltage values ​​corresponding to the multiple states of charge of the battery under test.

[0090] Continue with Figure 2 Let's take an example to illustrate. From... Figure 2 As can be seen from the graph, for the horizontal axis (i.e., the SOC coordinate), each SOC corresponds to a voltage value on each charging curve.

[0091] Assuming the first charging rate is 0.5C, that is... Figure 2 The charging curve corresponding to 0.5C is the first charging curve; meanwhile, it is assumed that the second charging rate is 2.0C, i.e. Figure 2 The charging curve corresponding to 2.0C is the second charging curve. Therefore, for a given state of charge (SOC), the first voltage corresponding to that SOC can be determined from the first charging curve, and the second voltage corresponding to that SOC can be determined from the second charging curve. Based on the second voltage and the first voltage, the differential voltage value corresponding to that SOC, i.e., the difference between the second voltage and the first voltage, can be calculated.

[0092] After determining the differential voltage values ​​corresponding to multiple SOCs, the lithium plating characteristic curve can be obtained. This also means that the lithium plating characteristic curve can be represented as a differential curve obtained by subtracting the second charging curve from the first charging curve.

[0093] Figure 4 An example of a set of lithium plating characteristic curves is shown. Figure 4 Each lithium plating characteristic curve in the data is based on... Figure 2 The charging curve corresponding to 0.5C is the first charging curve. The following are the charging curves: Figure 2 The charging curve corresponding to other charging rates is used as the second charging curve to obtain... Figure 4 The corresponding lithium plating characteristic curves are shown in the figure for other charging rates. That is, Figure 4 The lithium plating characteristic curve corresponding to 1.0C is obtained by... Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 1.0C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 1.5C is obtained by... Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 1.5C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 2.0C is obtained by... Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 2.0C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 2.5C is obtained by... Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 2.5C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 3.0C is obtained by... Figure 2The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 3.0C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 3.5C is obtained by... Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 3.5C (second charging curve) are determined. Figure 4 The lithium plating characteristic curve corresponding to 4.0C is obtained through Figure 2 The charging curve corresponding to 0.5C (first charging curve) and the charging curve corresponding to 4.0C (second charging curve) are determined.

[0094] By performing differential processing on the two charging curves based on the corresponding states of charge, the error caused by polarization in the normalized lithium plating characteristic curve can be reduced, thus enabling accurate determination of the lithium plating window.

[0095] According to some embodiments of this application, reference is made to Figure 5 Step 140 includes steps 510 to 520.

[0096] Step 510: Differentiate the lithium plating characteristic curve to obtain the lithium plating differential curve.

[0097] Step 520: Determine the lithium plating window based on the lithium plating differential curve.

[0098] like Figure 4 As shown, the lithium plating characteristic curves corresponding to different charging rates can reflect the lithium plating status of the battery under test. As mentioned above, when the charging rate is 1.0C or 1.5C, due to the relatively low charging rate, the battery under test may not exhibit lithium plating and will not show abnormal conditions such as low battery voltage. This is reflected in... Figure 4 In the charging curves corresponding to 1.0C and 1.5C, the lithium plating characteristic curves do not show a significant plateau as the State of Charge (SOC) increases (i.e., the voltage difference does not change with SOC or the change slows down significantly). However, when the charging rate increases, for example, to above 2.0C, the battery under test will exhibit lithium plating, leading to abnormal conditions such as low battery voltage. Once lithium plating occurs at a certain SOC, due to the low battery voltage and other abnormalities, the voltage of the battery under test may be lower than the voltage before lithium plating. Since the second charging curve represents the relationship between voltage and SOC when lithium plating occurs, while the first charging curve represents the relationship between voltage and SOC when lithium plating does not occur, this is reflected in... Figure 4The lithium plating characteristic curve, which is represented by the differential curve obtained by subtracting the first and second charging curves, shows that after lithium plating occurs, the voltage of the battery under test may be too low, i.e., the second voltage may be too low. This can cause a plateau in the voltage difference between the second and first voltages. In other words, after lithium plating occurs at a certain state of charge (SOC), the voltage difference does not change with increasing SOC or the change slows down significantly. Figure 4 The area indicated by the dashed box in the figure shows that as the charging rate increases, lithium plating occurs earlier and earlier, and the state of charge (SOC) at which lithium plating occurs gradually decreases.

[0099] Because in Figure 4 This only roughly indicates that lithium plating has occurred in the battery under test. To more accurately determine the lithium plating window, the lithium plating characteristic curve can be differentiated. Figure 4 Differential processing of the lithium plating characteristic curve in the figure yields... Figure 6 The lithium plating differential curve shown is illustrated. Since the lithium plating differential curve obtained after differential processing can reflect the changing trend of the lithium plating characteristic curve, the specific lithium plating window can be determined more accurately based on the lithium plating differential curve.

[0100] Differential processing of the lithium plating characteristic curve yields a lithium plating differential curve that shows the state of charge at which lithium plating begins in the battery under test, thus allowing for the determination of the precise lithium plating window.

[0101] According to some embodiments of this application, step 520 includes: determining the initial state of charge of lithium plating based on the state of charge corresponding to the valley point of the lithium plating differential curve and the lithium plating characteristic curve.

[0102] The lithium plating initiation state of charge indicates the state of charge of the battery under test at the second charge rate when lithium plating occurs.

[0103] Since the lithium plating differential curve is obtained by differentiating the lithium plating characteristic curve, it reflects the trend of the lithium plating characteristic curve at any SOC (State of Charge) (or can be represented as the slope of the lithium plating characteristic curve at that SOC). Therefore, each valley point of the lithium plating differential curve reflects the point with the smallest slope within a certain SOC range of the lithium plating characteristic curve. As analyzed above, the lithium plating characteristic curve can indicate the approximate range in which lithium plating occurs (represented by the approximate range where plateaus appear in the curve). Based on the valley points of the lithium plating differential curve, the specific SOC value at which the battery under test begins to exhibit lithium plating can be accurately determined.

[0104] Figure 7 Will Figure 6The lithium plating differential curves corresponding to different charging rates are illustrated separately. As mentioned above, it can be seen from the lithium plating characteristic curves that no lithium plating phenomenon occurs at charging rates of 1.0C and 1.5C, meaning there is no lithium plating window. At a charging rate of 2.0C, the lithium plating characteristic curve shows a plateau in the range of approximately 0.7-0.9. At this point, according to... Figure 7 The valley point of the lithium plating differential curve shown in the diagram within this range indicates that the initial state of charge for lithium plating is 77.8% (i.e., 0.778). Similarly, at a charging rate of 2.5C, the lithium plating characteristic curve shows a plateau between approximately 0.5 and 0.7. At this point, according to... Figure 7 The valley point of the lithium plating differential curve shown in the diagram within this range indicates that the initial state of charge for lithium plating is 60.1% (i.e., 0.601). At a charging rate of 3.0C, the lithium plating characteristic curve shows a plateau between approximately 0.45 and 0.65. At this point, according to... Figure 7 The valley point of the lithium plating differential curve shown in the diagram within this range indicates that the initial state of charge for lithium plating is 51.9% (i.e., 0.519). At a charging rate of 3.5C, the lithium plating characteristic curve shows a plateau between approximately 0.35 and 0.55. At this point, according to... Figure 7 The valley point of the lithium plating differential curve shown in the diagram within this range indicates that the initial state of charge for lithium plating is 42.4% (i.e., 0.424). At a charging rate of 4.0C, the lithium plating characteristic curve shows a plateau between approximately 0.25 and 0.5. At this point, according to... Figure 7 The valley point of the lithium plating differential curve shown in the figure in this range indicates that the initial state of charge for lithium plating is 27.7% (i.e., 0.277).

[0105] It should be noted that, Figure 2 , Figure 4 , Figure 6 and Figure 7 The different colors used for different curves are only for distinguishing the curves, and are not used to correspond the curves in different attached figures with the same color.

[0106] The valley point of the lithium plating differential curve can reflect the state of charge of the battery under test when lithium plating begins. By combining the lithium plating characteristic curve, the accurate state of charge at which lithium plating begins can be obtained.

[0107] According to some embodiments of this application, the analysis method 100 further includes: determining the charging strategy of the battery under test based on the lithium plating window of the battery under test at a second charging rate.

[0108] like Figure 7As shown, when the second charging rate is 4.0C, the corresponding initial state of charge (SOC) for lithium plating is 27.7%; when the second charging rate is 3.5C, the corresponding SOC for lithium plating is 42.4%; when the second charging rate is 3.0C, the corresponding SOC for lithium plating is 51.9%; when the second charging rate is 2.5C, the corresponding SOC for lithium plating is 60.1%; when the second charging rate is 2.0C, the corresponding SOC for lithium plating is 77.8%; and no lithium plating occurs when the second charging rate is 0.5C, 1.0C, or 1.5C.

[0109] Therefore, in order to improve charging efficiency while reducing the probability of lithium plating in the battery, the charging strategy can be determined based on the lithium plating window of the battery at a specific charging rate, which can also be understood as the state of charge at which lithium plating occurs, i.e., the initial state of charge for lithium plating.

[0110] Since batteries have different lithium plating windows at different charging rates, the charging strategy for the battery can be determined based on the lithium plating window of the battery under test at a specific charging rate, so that the charging effect can be improved without lithium plating.

[0111] According to some embodiments of this application, determining the charging strategy for the battery under test based on the lithium plating window of the battery under test at a second charging rate includes: in response to the battery under test not reaching a predetermined state of charge, charging the battery under test at a second charging rate.

[0112] The predetermined state of charge is less than or equal to the initial state of charge of lithium plating.

[0113] Since lithium plating will occur when the battery under test reaches the lithium plating initiation state of charge during charging, a specific charging rate can be used to charge the battery. Once the battery reaches a predetermined state of charge, this charging rate can be discontinued, thereby reducing the risk of lithium plating. The predetermined state of charge can be determined based on the lithium plating initiation state of charge corresponding to that charging rate.

[0114] The battery under test is charged at a specific charging rate until the battery reaches a predetermined state of charge. Since the predetermined state of charge is less than or equal to the lithium plating initiation state of charge, the battery under test has not yet started to plating lithium when the predetermined state of charge is reached. This can reduce the risk of lithium plating during the charging process and reduce the impact of lithium plating on battery performance.

[0115] According to some embodiments of this application, the predetermined state of charge is set to be greater than or equal to 70% and less than or equal to 90% of the lithium plating initiation state of charge.

[0116] To further reduce the risk of lithium plating in the battery, the predetermined state of charge (SOC) can be set to be less than the lithium plating SOC. However, to improve charging efficiency, the predetermined SOC should not be set too low. Therefore, the predetermined SOC can be set to be greater than or equal to 70% and less than or equal to 90% of the initial lithium plating SOC.

[0117] exist Figure 7 In the examples shown, when the second charge rate is 4.0C, the corresponding initial state of charge (SOC) for lithium plating is 27.7%, and the predetermined SOC can be set to 20%; when the second charge rate is 3.5C, the corresponding initial SOC for lithium plating is 42.4%, and the predetermined SOC can be set to 30%; when the second charge rate is 3.0C, the corresponding initial SOC for lithium plating is 51.9%, and the predetermined SOC can be set to 40%; when the second charge rate is 2.5C, the corresponding initial SOC for lithium plating is 60.1%, and the predetermined SOC can be set to 50%; when the second charge rate is 2.0C, the corresponding initial SOC for lithium plating is 77.8%, and the predetermined SOC can be set to 60%; when the second charge rate is 0.5C, 1.0C, or 1.5C, no lithium plating occurs, and the predetermined SOC can be set to 100%.

[0118] By properly setting the predetermined state of charge, the risk of lithium plating in the battery can be further reduced while improving charging efficiency and charging effect.

[0119] According to some embodiments of this application, the predetermined state of charge is set to 72% of the lithium plating initiation state of charge.

[0120] Considering the impact of consistency among multiple batteries, the predetermined state of charge can be set to 72% of the initial state of charge at which lithium plating begins. At this point, the charging strategy can be applied during the mass production process of the battery, reducing the risk of lithium plating in some batteries due to poor consistency.

[0121] By setting a reasonable state of charge, the resulting charging strategy can be applied to the battery mass production process, thereby achieving reasonable control of the mass production process.

[0122] According to some embodiments of this application, determining the charging strategy of the battery under test based on the lithium plating window of the battery under test at the second charging rate further includes: charging the battery under test at the third charging rate in response to the battery under test reaching a predetermined state of charge.

[0123] The third charging rate is less than the second charging rate.

[0124] As analyzed above, the initial state of charge (SOC) for lithium plating gradually increases as the charging rate decreases. Therefore, once the battery has reached the predetermined SOC at a certain charging rate (e.g., the second charging rate), it is not necessary to continue charging at that rate. Instead, a smaller charging rate (e.g., the third charging rate) can be used. Since the SOC for lithium plating at the third charging rate is greater than that at the second charging rate, lithium plating can be delayed.

[0125] Continue with Figure 7 The following examples illustrate this. To improve charging efficiency, the battery can be charged at a 4.0C charging rate. When the battery's state of charge (SOC) reaches a predetermined SOC corresponding to 4.0C (e.g., 20%), it can be charged at a 3.5C charging rate. When the battery's SOC reaches a predetermined SOC corresponding to 3.5C (e.g., 30%), it can be charged at a 3.0C charging rate. When the battery's SOC reaches a predetermined SOC corresponding to 3.0C (e.g., 40%), it can be charged at a 2.5C charging rate. When the battery's SOC reaches a predetermined SOC corresponding to 2.5C (e.g., 50%), it can be charged at a 2.0C charging rate. When the battery's SOC reaches a predetermined SOC corresponding to 2.0C (e.g., 60%), it can be charged at a 1.0C or 1.5C charging rate. Since lithium plating will not occur in the battery under test when the charging rate is 1.0C or 1.5C, this charging rate can be used to charge until the battery's state of charge reaches 100%. In one example, to improve the reliability of the charging process, the battery can be charged at a charging rate of 1.0C until the battery's state of charge reaches 100%.

[0126] Since a smaller charging rate results in a larger initial state of charge for lithium plating, the charging rate can be reduced once the battery under test reaches the predetermined state of charge, allowing the battery to continue charging and thus achieving reasonable control of the charging process.

[0127] According to some embodiments of this application, the analysis method 100 further includes: determining whether the battery under test meets the preset usage conditions based on the lithium plating window of the battery under test at the second charging rate.

[0128] The presence of anomalies in a battery under test can be determined by observing whether its lithium plating window is abnormal at a specific charging rate. In some embodiments, the lithium plating window at different charging rates can be predetermined during the mass production process. If a battery exhibits a significant decrease in its lithium plating window, it can be considered potentially abnormal and intercepted to prevent it from entering the market and causing malfunctions.

[0129] By observing the lithium plating window of the battery under test, it is possible to determine whether the battery's performance is normal, thereby reducing the risk of abnormal batteries entering subsequent use stages.

[0130] According to some embodiments of this application, determining whether the battery under test meets the preset usage conditions based on the lithium plating window of the battery under test at the second charging rate includes: in response to the lithium plating initiation state of charge of the battery under test being less than the preset threshold state of charge, determining that the battery under test does not meet the preset usage conditions.

[0131] Taking a second charging rate of 3.0C as an example, if the threshold state of charge is set to 45% (±3) based on the test data during mass production, then when the initial state of charge of lithium plating of a certain battery or a batch of batteries at a charging rate of 3.0C is less than the threshold state of charge, it can be considered that this part of the battery is abnormal and needs to be evaluated. For example, it can be intercepted or the charging strategy can be re-determined for the same batch of batteries.

[0132] By determining whether the lithium plating initiation state of charge of the battery under test is less than the threshold state of charge, it is possible to accurately identify and intercept abnormal batteries.

[0133] According to some embodiments of this application, step 140 further includes: after step 510: performing noise reduction processing on the lithium plating differential curve.

[0134] Because noise can affect the curve determination process, the resulting lithium plating differential curve may contain anomalies such as spikes. To obtain more accurate analytical results, noise reduction processing can be performed on the lithium plating differential curve to obtain a smooth curve.

[0135] By denoising the curves, the errors introduced by noise during the analysis process can be reduced, thereby improving the accuracy of the analysis.

[0136] According to some embodiments of this application, the analysis method 100 further includes a first process 800. (See also...) Figure 8 The first process 800 includes steps 810 to 830.

[0137] Step 810: Determine the battery capacity of the battery to be tested.

[0138] Step 820: Determine the charge level of the battery to be tested.

[0139] Step 830: Determine the state of charge of the battery to be tested based on the charging capacity and battery capacity.

[0140] Since the lithium plating window is represented by the state of charge (SCC) to be tested in the embodiments of this application, it is necessary to accurately determine the SCC of the battery under test. The SCC of the battery under test can be determined by determining the battery capacity and the real-time charging amount during the charging process, i.e., the ratio of the real-time charging amount to the battery capacity.

[0141] By determining the state of charge of the battery under test, an accurate charging curve can be obtained, leading to more accurate analysis results.

[0142] According to some embodiments of this application, reference is made to Figure 9 Step 810 includes steps 910 to 980.

[0143] Step 910: Perform constant current charging on the battery under test at the fourth charging rate.

[0144] Step 920: In response to the voltage of the battery under test reaching the first threshold voltage, the battery under test is charged at a constant voltage using the first threshold voltage.

[0145] Step 930: In response to the charging current of the battery under test reaching the first threshold current, charging of the battery under test is stopped.

[0146] Step 940: Perform constant current discharge on the battery to be tested at the first discharge rate.

[0147] Step 950: In response to the voltage of the battery under test reaching the second threshold voltage, determine the first discharge capacity of the battery under test. The first discharge capacity indicates the amount of electricity discharged by the battery under test during constant current discharge at a first discharge rate.

[0148] Step 960: Perform constant current discharge on the battery to be tested at the second discharge rate.

[0149] Step 970: In response to the voltage of the battery under test reaching the third threshold voltage, determine the second discharge capacity of the battery under test. The second discharge capacity indicates the amount of electricity discharged by the battery under test during constant current discharge at the second discharge rate.

[0150] Step 980: The sum of the first discharge capacity and the second discharge capacity is determined as the battery capacity of the battery to be tested.

[0151] In the above steps, the fourth charging rate, the first threshold voltage, the first threshold current, the first discharging rate, the second threshold voltage, the second discharging rate, and the third threshold voltage can be designed according to the performance of the battery under test. The fourth charging rate, the first discharging rate, and the second discharging rate can be set to be the same or different from each other, and the first threshold voltage, the second threshold voltage, and the third threshold voltage can also be set to be the same or different from each other; this application does not impose any limitations on this.

[0152] Table 1 illustrates an example of steps 910 to 980.

[0153] Table 1

[0154]

[0155]

[0156] It should be understood that Table 1 is just an example, and the charging rate and other parameters therein can be flexibly adjusted according to the usage (e.g., battery type, battery parameters, etc.), and this disclosure does not limit this.

[0157] Precisely determining the battery capacity of the battery under test can yield a more accurate state of charge, improving the accuracy of the analysis process.

[0158] According to some embodiments of this application, the analysis method 100 further includes a second process 1000 following step 110 and / or step 120. (See reference...) Figure 10 The second process 1000 includes steps 1010 to 1040.

[0159] Step 1010: In response to the voltage of the battery under test reaching the fourth threshold voltage, charging of the battery under test is stopped.

[0160] Step 1020: Perform constant current discharge on the battery to be tested at the third discharge rate.

[0161] Step 1030: In response to the voltage of the battery under test reaching the fifth threshold voltage, the battery under test is subjected to constant current discharge at the fourth discharge rate.

[0162] Step 1040: In response to the voltage of the battery under test reaching the sixth threshold voltage, stop discharging the battery under test.

[0163] During the analysis of the lithium plating window, the battery under test can be cycled through charge and discharge to obtain multiple charging curves as needed. Steps 1010 to 1040 can be set after steps 110 and / or 120.

[0164] In the above steps, the fourth threshold voltage, the third discharge rate, the fifth threshold voltage, the fourth discharge rate, and the sixth threshold voltage can be designed according to the performance of the battery under test. The third discharge rate and the fourth discharge rate can be set to be the same or different from each other, and the fourth threshold voltage, the fifth threshold voltage, and the sixth threshold voltage can also be set to be the same or different from each other; this application does not impose any limitations on this.

[0165] Table 2 illustrates an example of steps 1010 to 1040 following step 110 and / or step 120.

[0166] Table 2

[0167]

[0168]

[0169] It should be understood that Table 2 is just an example, and the charging rate and other parameters therein can be flexibly adjusted according to the usage (e.g., battery type, battery parameters, etc.), and this disclosure does not limit this.

[0170] In some embodiments, the fourth discharge rate can be set to be less than the third discharge rate. In the example shown in Table 2, in step 1020, the battery under test is discharged at a discharge rate of 0.33C, during which polarization effects may occur. In step 1030, the battery under test is discharged at a discharge rate of 0.05C. Due to the lower discharge rate, a slow discharge state is achieved, which can reduce polarization effects and improve the accuracy of the analysis process.

[0171] Test procedures 1) to 6) in Table 2 can be repeated. By changing the charging rate xxC in test procedure 2), multiple charging curves corresponding to different charging rates can be obtained. For example, when test procedure 2) includes step 110, after executing test procedure 6), xxC can be changed to the second charging rate, i.e., step 120 can be executed.

[0172] By charging the battery under test and then discharging it again, the charging curves at multiple different charging rates can be tested cyclically, thus improving testing efficiency.

[0173] Based on the same technical concept, embodiments of this application provide an analytical apparatus for a lithium plating window. Embodiments of the analytical apparatus for a lithium plating window can be referenced to embodiments of the analytical method for a lithium plating window; details that are repeated will not be repeated. Reference Figure 11 The analysis device 1100 for the lithium plating window includes a first module 1110, a second module 1120, a third module 1130, and a fourth module 1140.

[0174] The first module 1110 is used to charge the battery under test at a first charging rate to obtain a first charging curve of the battery under test. The first charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the first charging rate.

[0175] The second module 1120 is used to charge the battery under test at a second charging rate to obtain a second charging curve of the battery under test. The second charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the second charging rate.

[0176] The third module 1130 is used to determine the lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve. The lithium plating characteristic curve is used to indicate the lithium plating status of the battery under test.

[0177] The fourth module 1140 is used to determine the lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve.

[0178] The first module 1110, the second module 1120, the third module 1130, and the fourth module 1140 in the lithium plating window analysis apparatus 1100 can correspond to steps 110 to 140 in the lithium plating window analysis method 100, and will not be described in detail here for the sake of brevity. It should be understood that, corresponding to the embodiment of the lithium plating window analysis method 100, the embodiment of the lithium plating window analysis apparatus 1100 may also include more modules.

[0179] It should be noted that the functions of the modules discussed herein can be divided into multiple modules, and / or at least some functions of multiple modules can be combined into a single module. The specific actions performed by a particular module discussed herein include the specific module itself performing the action, or alternatively, the specific module calling or otherwise accessing another component or module that performs the action (or performs the action in conjunction with the specific module). Therefore, a specific module performing an action can include the specific module performing the action itself and / or another module that performs the action, called or otherwise accessed by the specific module.

[0180] It should also be understood that this article can describe various technologies in the general context of software and hardware components or program modules. The above regarding... Figure 11The described modules can be implemented in hardware or in hardware in combination with software and / or firmware. For example, these modules can be implemented as computer program code / instructions configured to execute in one or more processors and stored in a computer-readable storage medium. Alternatively, these modules can be implemented as hardware logic / circuit. Hardware logic / circuit may include integrated circuit chips (which include processors (e.g., Central Processing Unit (CPU), microcontrollers, microprocessors, digital signal processors (DSPs), etc.), memory, one or more communication interfaces, and / or one or more components of other circuitry), and may optionally execute received program code and / or include embedded firmware to perform functions.

[0181] This application provides a computing device 1200, such as... Figure 12 As shown. Figure 12 An example configuration of a computing device 1200 that can be used to implement the lithium plating window analysis method 100 described herein is shown. For example, the lithium plating window analysis apparatus 1100 described above may be implemented wholly or at least partially by the computing device 1200 or a similar device or system.

[0182] The computing device 1200 may include at least one processor 1205 capable of communicating with each other, such as via a bus 1204 or other suitable connection, a memory 1207, multiple communication interfaces 1202, a display device 1201, other input / output (I / O) devices 1203, and one or more mass storage devices 1206. Instructions are stored on the memory 1207 that, when executed by the processor 1205, cause the processor 1205 to perform an analysis method for the lithium plating window as described in the above embodiments.

[0183] The computing device 1200 can be a variety of different types of devices. Examples of the computing device 1200 include, but are not limited to: desktop computers, server computers, laptop or netbook computers, mobile devices (e.g., tablet computers, cellular or other wireless phones (e.g., smartphones), notebook computers, mobile stations), wearable devices (e.g., glasses, watches), entertainment devices (e.g., entertainment appliances, set-top boxes communicatively coupled to a display device, game consoles), televisions or other display devices, automotive computers, and so on.

[0184] Processor 1205 may be a single processing unit or multiple processing units, and all processing units may include single or multiple computing units or multiple cores. Processor 1205 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operating instructions. Among other capabilities, processor 1205 may be configured to acquire and execute computer-readable instructions stored in memory 1207, mass storage device 1206, or other computer-readable media, such as program code of operating system 1208, program code of application program 1209, program code of other program 1210, etc.

[0185] Memory 1207 and mass storage device 1206 are examples of computer-readable storage media for storing instructions executed by processor 1205 to perform the various functions described above. For example, memory 1207 may generally include both volatile and non-volatile memory (e.g., RAM, ROM, etc.). Furthermore, mass storage device 1206 may generally include hard disk drives, solid-state drives, removable media, including external and removable drives, memory cards, flash memory, floppy disks, optical disks (e.g., CDs, DVDs), storage arrays, network-attached storage, storage area networks, etc. Both memory 1207 and mass storage device 1206 may be collectively referred to herein as memory or computer-readable storage media, and may be non-transitory media capable of storing computer-readable, processor-executable program instructions as computer program code, which may be executed by processor 1205 as a specific machine configured to perform the operations and functions described in the examples herein.

[0186] Multiple programs can be stored on mass storage device 1206. These programs include operating system 1208, one or more application programs 1209, other programs 1210, and program data 1211, and they can be loaded into memory 1207 for execution. Examples of such application programs or program modules may include, for example, computer program logic (e.g., computer program code or instructions) for implementing lithium plating window analysis apparatus 1100 (including first module 1110, second module 1120, third module 1130, and fourth module 1140), lithium plating window analysis method 100 (including any suitable steps of lithium plating window analysis method 100), and / or other embodiments described herein.

[0187] Although Figure 12The data is illustrated as being stored in memory 1207 of computing device 1200, but operating system 1208, application program 1209, other program 1210 and program data 1211 or portions thereof may be implemented using any form of computer-readable medium accessible by computing device 1200.

[0188] One or more communication interfaces 1202 are used for exchanging data with other devices, such as via a network, direct connection, etc. Such communication interfaces can be one or more of the following: any type of network interface (e.g., a network interface card (NIC)), wired or wireless (such as IEEE 802.11 Wireless LAN (WLAN)) interface, Wi-MAX interface, Ethernet interface, Universal Serial Bus (USB) interface, cellular network interface, Bluetooth™ interface, Near Field Communication (NFC) interface, etc. Communication interface 1202 can facilitate communication across various network and protocol types, including wired networks (e.g., LAN, cable, etc.) and wireless networks (e.g., WLAN, cellular, satellite, etc.), the Internet, etc. Communication interface 1202 can also provide communication with external storage devices (not shown), such as storage arrays, network-attached storage, storage area networks, etc.

[0189] In some examples, a display device 1201, such as a monitor, may be included for displaying information and images to the user. Other I / O devices 1203 may be devices that receive various inputs from the user and provide various outputs to the user, and may include touch input devices, gesture input devices, cameras, keyboards, remote controls, mice, printers, audio input / output devices, and so on.

[0190] The techniques described herein can be supported by these various configurations of computing device 1200, and are not limited to specific examples of the techniques described herein. For example, the functionality can also be implemented wholly or partially on a “cloud” using a distributed system. A cloud includes and / or represents a platform for resources. The platform abstracts the underlying functionality of the cloud’s hardware (e.g., servers) and software resources. Resources may include applications and / or data that can be used when performing computational processing on servers remote from computing device 1200. Resources may also include services provided via the Internet and / or via subscriber networks such as cellular or Wi-Fi networks. The platform can abstract resources and functionality to connect computing device 1200 to other computing devices. Therefore, the implementation of the functionality described herein can be distributed throughout the cloud. For example, the functionality can be implemented partly on computing device 1200 and partly through a platform that abstracts the functionality of the cloud.

[0191] This application also provides a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods described in any of the above embodiments.

[0192] Computer-readable storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, DVD, or other optical storage devices, magnetic cassettes, magnetic tapes, disk storage devices or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by computer equipment.

[0193] This application also provides a computer program product including instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods as described in any of the above embodiments.

[0194] A specific embodiment of this application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the scope of this application.

[0195] The battery under test is charged at a first charging rate and a second charging rate, respectively, to obtain a first charging curve and a second charging curve. The first charging rate can be the charging rate at which lithium plating does not occur when the battery is charged to its maximum voltage; for example, it can be set to 0.5C. The second charging rate can be the charging rate at which lithium plating occurs when the battery is charged to its maximum voltage; for example, it can be set to 2C. Figure 2 As shown, taking a first charging rate of 0.5C and a second charging rate of 2.0C as an example, Figure 2 The charging curve corresponding to 0.5C is the first charging curve, and the charging curve corresponding to 2.0C is the second charging curve. For a given state of charge (SOC), the first voltage corresponding to that SOC can be determined from the first charging curve, and the second voltage corresponding to that SOC can be determined from the second charging curve. Based on the second and first voltages, the differential voltage value corresponding to that SOC can be calculated, which is the difference between the second and first voltages. After determining the differential voltage values ​​corresponding to multiple SOCs, the lithium plating characteristic curve can be obtained, which is the differential curve obtained by subtracting the second and first charging curves, for example... Figure 4 The lithium plating characteristic curve corresponds to 2.0C.

[0196] The lithium plating characteristic curve is differentiated, and the resulting lithium plating differential curve is then noise-reduced. Based on the state of charge corresponding to the valley point of the lithium plating differential curve and the lithium plating characteristic curve, the initial state of charge for lithium plating can be determined, i.e., the state of charge at which lithium plating occurs in the tested battery at a charging rate of 2.0C. For example... Figure 4 and Figure 7 As shown, at a charging rate of 2.0C, the lithium plating characteristic curve shows a plateau between approximately 0.7 and 0.9, meaning that lithium plating begins to occur when the state of charge of the tested battery is between 0.7 and 0.9. Figure 7 The valley point of the lithium plating differential curve corresponding to 2.0C in this range indicates that the initial state of charge for lithium plating is 77.8% (i.e., 0.778).

[0197] After determining the lithium plating window corresponding to a specific charging rate, a charging strategy for the battery under test can be further determined. A predetermined state of charge (SOC) can be set for each charging rate, which can be set to 72% of the initial SOC corresponding to that charging rate. When the SOC of the battery under test has not reached the predetermined SOC, it is charged at that charging rate. Conversely, when the SOC of the battery under test reaches the predetermined SOC, the charging rate can be reduced to charge the battery at a lower rate.

[0198] After determining the lithium plating window corresponding to a specific charging rate, it is possible to further determine whether the battery under test is abnormal. A threshold state of charge can be set for each charging rate. When the initial state of charge of lithium plating of the battery under test at that charging rate is less than the threshold state of charge, the battery under test is considered abnormal and needs to be intercepted or the charging strategy needs to be redefined.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for analyzing lithium plating windows, characterized in that, include: The battery under test is charged at a first charging rate to obtain a first charging curve of the battery under test. The first charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the first charging rate. The battery under test is charged at a second charging rate to obtain a second charging curve of the battery under test. The second charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the second charging rate. Based on the first charging curve and the second charging curve, a lithium plating characteristic curve of the battery under test is determined, wherein the lithium plating characteristic curve is used to indicate the lithium plating status of the battery under test; and Based on the lithium plating characteristic curve, the lithium plating window of the battery under test at the second charging rate is determined.

2. The analytical method according to claim 1, characterized in that, The first charging rate includes the charging rate at which the battery under test does not exhibit lithium plating during the charging process to its maximum voltage.

3. The analytical method according to claim 2, characterized in that, The first charging rate is set to be greater than 0 and less than or equal to 1.5C.

4. The analytical method according to claim 2 or 3, characterized in that, The first charging rate is set to 0.5C.

5. The analytical method according to any one of claims 1-4, characterized in that, The second charging rate includes the charging rate at which lithium plating occurs during the charging of the battery under test to its maximum voltage.

6. The analytical method according to any one of claims 1-5, characterized in that, The step of determining the lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve includes: For any state of charge of the battery under test: Based on the first charging curve, determine the first voltage corresponding to the state of charge; Based on the second charging curve, determine the second voltage corresponding to this state of charge; and Based on the difference between the second voltage and the first voltage, determine the differential voltage value corresponding to the state of charge; and The lithium plating characteristic curve is determined based on the differential voltage values ​​corresponding to the multiple states of charge of the battery under test.

7. The analytical method according to any one of claims 1-6, characterized in that, The step of determining the lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve includes: The lithium plating characteristic curve is differentiated to obtain a lithium plating differential curve; and The lithium plating window is determined based on the lithium plating differential curve.

8. The analytical method according to claim 7, characterized in that, Determining the lithium plating window based on the lithium plating differential curve includes: Based on the state of charge corresponding to the valley point of the lithium plating differential curve and the lithium plating characteristic curve, the initial state of charge for lithium plating is determined. The initial state of charge for lithium plating indicates the state of charge of the battery under test at which lithium plating occurs under the second charging rate.

9. The analytical method according to claim 8, characterized in that, The analytical method further includes: The charging strategy of the battery under test is determined based on the lithium plating window of the battery under test at the second charging rate.

10. The analytical method according to claim 9, characterized in that, The step of determining the charging strategy of the battery under test based on the lithium plating window of the battery under test at the second charging rate includes: In response to the fact that the state of charge of the battery under test has not reached the predetermined state of charge, the battery under test is charged at the second charging rate, wherein the predetermined state of charge is less than or equal to the lithium plating initiation state of charge.

11. The analytical method according to claim 10, characterized in that, The predetermined state of charge is set to be greater than or equal to 70% and less than or equal to 90% of the lithium plating initiation state of charge.

12. The analytical method according to claim 10 or 11, characterized in that, The predetermined state of charge is set to 72% of the lithium plating initiation state of charge.

13. The analytical method according to any one of claims 10-12, characterized in that, The step of determining the charging strategy of the battery under test based on the lithium plating window of the battery under test at the second charging rate further includes: In response to the battery under test reaching the predetermined state of charge, the battery under test is charged at a third charging rate, which is less than the second charging rate.

14. The analytical method according to any one of claims 8-13, characterized in that, The analytical method further includes: Based on the lithium plating window of the battery under test at the second charging rate, determine whether the battery under test meets the preset usage conditions.

15. The analytical method according to claim 14, characterized in that, The step of determining whether the battery under test meets the preset usage conditions based on the lithium plating window of the battery under test at the second charging rate includes: In response to the lithium plating initiation state of charge of the battery under test being less than a preset threshold state of charge, it is determined that the battery under test does not meet the preset usage conditions.

16. The analytical method according to any one of claims 7-15, characterized in that, The step of determining the lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve further includes: After differentiating the lithium plating characteristic curve to obtain the lithium plating differential curve: The lithium plating differential curve is subjected to noise reduction processing.

17. The analytical method according to any one of claims 1-16, characterized in that, The analytical method further includes: Determine the battery capacity of the battery to be tested; Determine the charge capacity of the battery under test; and The state of charge of the battery under test is determined based on the charging capacity and the battery capacity.

18. The analytical method according to claim 17, characterized in that, Determining the battery capacity of the battery under test includes: The battery under test was charged at a constant current rate using the fourth charging rate. In response to the voltage of the battery under test reaching a first threshold voltage, the battery under test is charged at a constant voltage using the first threshold voltage. In response to the charging current of the battery under test reaching a first threshold current, charging of the battery under test is stopped; The battery under test is subjected to constant current discharge at a first discharge rate. In response to the voltage of the battery under test reaching a second threshold voltage, a first discharge capacity of the battery under test is determined, wherein the first discharge capacity indicates the amount of electricity discharged by the battery under test during constant current discharge at the first discharge rate; The battery under test was subjected to constant current discharge at a second discharge rate. In response to the voltage of the battery under test reaching a third threshold voltage, a second discharge capacity of the battery under test is determined, the second discharge capacity indicating the amount of electricity discharged by the battery under test during constant current discharge at a second discharge rate; and The sum of the first discharge capacity and the second discharge capacity is determined as the battery capacity of the battery under test.

19. The analytical method according to any one of claims 1-18, characterized in that, The analytical method further includes: After the battery under test is charged at the first charging rate and / or after the battery under test is charged at the second charging rate: In response to the voltage of the battery under test reaching the fourth threshold voltage, charging of the battery under test is stopped; The battery under test was subjected to constant current discharge at the third discharge rate. In response to the voltage of the battery under test reaching a fifth threshold voltage, the battery under test is subjected to constant current discharge at a fourth discharge rate; and In response to the voltage of the battery under test reaching the sixth threshold voltage, the discharge of the battery under test is stopped.

20. An analytical apparatus for a lithium plating window, characterized in that, include: The first module is used to charge the battery under test at a first charging rate to obtain a first charging curve of the battery under test. The first charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the first charging rate. The second module is used to charge the battery under test at a second charging rate to obtain a second charging curve of the battery under test. The second charging curve indicates the correspondence between the voltage and the state of charge of the battery under test during the charging process at the second charging rate. The third module is used to determine the lithium plating characteristic curve of the battery under test based on the first charging curve and the second charging curve. The lithium plating characteristic curve is used to indicate the lithium plating status of the battery under test. as well as The fourth module is used to determine the lithium plating window of the battery under test at the second charging rate based on the lithium plating characteristic curve.

21. A computing device, characterized in that, include: At least one processor; as well as At least one memory communicatively connected to the at least one processor, the at least one memory storing instructions that, when executed individually or jointly by the at least one processor, cause the computing device to perform the analysis method of any one of claims 1 to 19.

22. A computer-readable storage medium, characterized in that, The device stores instructions that, when executed individually or jointly by one or more processors of the computing device, cause the computing device to perform the analysis method of any one of claims 1 to 19.

23. A computer program product, characterized in that, The instructions include instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the analysis method of any one of claims 1 to 19.

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