Method for estimating safety of negative electrode and battery system using same

Abstract

A method of estimating safety of a negative electrode and a battery system using the same are disclosed. In one embodiment, a method of estimating negative electrode safety by at least one processor includes receiving first charging data about at least one cell from a voltage sensor, receiving second charging data about the at least one cell from the voltage sensor by the at least one processor, and estimating, by the at least one processor, the negative electrode safety of the at least one cell based on the first charging data and the second charging data, wherein the first charging data has a different charging rate than the second charging signal.

Description

Technical Field

[0001] The implementation methods relate to a method for estimating the safety of the negative electrode and a battery system using the same, specifically, to a method for estimating the safety of the negative electrode of a battery based on battery charging data, and a battery system using the method. Background Technology

[0002] Unlike primary batteries, which are not designed for (re)charging, secondary (or rechargeable) batteries are designed for discharging and recharging. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources to drive motors in hybrid and electric vehicles, as well as for storing electricity (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly consisting of positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] As batteries, including rechargeable batteries, become high-energy and require rapid charging, safety becomes paramount. In particular, lithium metal plating degradation at the negative electrode of the battery is the most common cause of fires and is associated with the state of degradation of the negative electrode. Furthermore, understanding the state of negative electrode degradation within the battery can be important for optimal battery performance and reuse.

[0004] The information disclosed in this background section is intended to enhance understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0005] The implementation includes a method for estimating the safety of a negative electrode, the method comprising receiving first charging data about at least one cell from a voltage sensor by at least one processor, receiving second charging data about at least one cell from a voltage sensor by at least one processor, and estimating the safety of the negative electrode of at least one cell by at least one processor based on the first charging data and the second charging data, wherein the first charging data and the second charging data have different charging rates.

[0006] The first charging data may include first charging voltage data based on the charging capacity obtained by charging at least one individual cell at a first charging rate, and the second charging data may include second charging voltage data based on the charging capacity obtained by charging at least one individual cell at a second charging rate.

[0007] The first charging rate may be slower than the second charging rate, and the second charging rate may be equal to or lower than a predetermined threshold.

[0008] The method may further include calculating a first differential voltage data of the first charging voltage data, and calculating a second differential voltage data of the second charging voltage data.

[0009] The first differential voltage data may include the first peak charging capacity and the first peak charging capacity, and the second differential voltage data may include the second peak charging capacity. The first peak charging capacity may be included in the first charging region, and the first peak charging capacity and the second peak charging capacity may be included in the second charging region.

[0010] Estimating the negative electrode safety of at least one cell includes estimating the negative electrode safety based on the first-1 peak charge capacity, the first-2 peak charge capacity, and the second peak charge capacity.

[0011] Estimating the negative electrode safety of at least one cell may include calculating the amount of peak variation based on the first and second peak charging capacities, and estimating the negative electrode safety based on the amount of peak variation, the first peak charging capacity, and the first and second peak charging capacities.

[0012] The at least one cell can be a lithium secondary battery, and the amount of peak variation is related to the degree of lithium plating on the negative electrode included in the at least one cell.

[0013] If the state of charge (SoC) of at least one cell is below the SoC threshold, first charging data and second charging data can be generated by charging at least one cell.

[0014] The method may further include receiving third charging data associated with the early lifetime (BoL) of at least one cell, wherein estimating the negative electrode safety of at least one cell includes estimating the negative electrode safety of at least one cell based on first charging data to third charging data, the first charging data to third charging data including first charging data, second charging data and third charging data.

[0015] Estimating the negative electrode safety of at least one cell based on the first to third charging data may include calculating the negative electrode health of at least one cell based on the first and second charging data, calculating a reference negative electrode health associated with the BoL of at least one cell based on the third charging data, and estimating the negative electrode safety based on the negative electrode health and the reference negative electrode health.

[0016] The first charging data may include first charging voltage data based on the charging capacity obtained by charging at least one cell at a first charging rate, the second charging data may include second charging voltage data based on the charging capacity obtained by charging at least one cell at a second charging rate, and the third charging data may include third charging voltage data based on the charging capacity obtained by charging at least one cell associated with BoL. The method may further include calculating a first differential voltage data of the first charging voltage data, calculating a second differential voltage data of the second charging voltage data, and calculating a third differential voltage data of the third charging voltage data, wherein the first differential voltage data may include a first_1 peak charging capacity and a first_2 peak charging capacity, wherein the second differential voltage data includes a second peak charging capacity, and wherein the third differential voltage data includes a third_1 peak charging capacity and a third_2 peak charging capacity, wherein the first_1 peak charging capacity and the third_1 peak charging capacity are included in a first charging region, and wherein the first_2 peak charging capacity, the second peak charging capacity, and the third_2 peak charging capacity are included in a second charging region.

[0017] Estimating the negative electrode safety of at least one cell based on the first to third charging data may include estimating the negative electrode safety of at least one cell based on the first_1 peak charging capacity to the third_2 peak charging capacity, wherein the first_1 peak charging capacity to the third_2 peak charging capacity includes the first_1 peak charging capacity, the first_2 peak charging capacity, the second peak charging capacity, the third_1 peak charging capacity, and the third_2 peak charging capacity.

[0018] At least one cell can be charged until at least one cell is fully charged. The first charging data includes the full charge capacity associated with the first charging data, and the negative electrode safety of at least one cell is estimated based on the first charging data to the third charging data, including estimating the negative electrode safety of at least one cell based on the full charge capacity associated with the first charging data and the first_1 peak charge capacity to the third_2 peak charge capacity.

[0019] The safety of the negative electrode can be associated with a decrease in the capacitance of the negative electrode and an increase in its resistance.

[0020] The method may further include adjusting the upper limit of the charging rate of at least one cell based on an estimated negative electrode safety.

[0021] Adjusting the upper limit of the charging rate for at least one cell may include reducing the upper limit of the charging rate in response to determining that the safety of the negative electrode is below a safety threshold.

[0022] The implementation includes a battery system comprising a voltage sensor configured to measure a voltage based on the charge capacity of at least one cell and a controller configured to receive charging data generated by the voltage sensor and estimate the negative electrode safety of at least one cell based on the charging data, wherein the charging data includes first charging data with respect to at least one cell and second charging data with respect to at least one cell, and wherein the first charging data and the second charging data have different charging rates.

[0023] The charging data may further include third charging data associated with the early life (BoL) of at least one cell, and the controller may be further configured to calculate the negative electrode health of at least one cell based on the first charging data and the second charging data, calculate a reference negative electrode health associated with the BoL of at least one cell based on the third charging data, and estimate the negative electrode safety based on the negative electrode health and the reference negative electrode health.

[0024] The controller can be further configured to adjust the upper limit of the charging rate of at least one cell based on an estimated negative electrode safety.

[0025] These and other aspects and features of this disclosure will be described in or will become apparent from the following description of embodiments of this disclosure.

[0026] However, the aspects and features of this disclosure are not limited to those described above, and those skilled in the art will clearly understand other aspects and features not mentioned from the detailed description below. Attached Figure Description

[0027] The accompanying drawings illustrate embodiments of the present disclosure and further describe aspects and features of the disclosure together with the detailed description thereof. Therefore, the disclosure should not be construed as limited to the drawings, wherein:

[0028] Figure 1 The illustration shows a conceptual view of a battery system 120 according to one or more embodiments of the present disclosure;

[0029] Figure 2 The figure is a block diagram illustrating the internal configuration of the controller 200 according to one or more embodiments of the present disclosure;

[0030] Figure 3 The illustration shows an example of charging voltage data for a negative electrode half-cell according to one or more embodiments of the present disclosure.

[0031] Figure 4 The illustration shows an example of differential voltage data for a negative electrode half-cell according to one or more embodiments of the present disclosure.

[0032] Figure 5The figure shows a graph illustrating an example relationship between the peak charge capacity of a negative electrode half-cell and the length of the lithium plating risk region according to one or more embodiments of the present disclosure.

[0033] Figure 6 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure;

[0034] Figure 7 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure;

[0035] Figure 8 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure;

[0036] Figure 9 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure;

[0037] Figure 10 The illustration shows a flowchart illustrating an example of a method for estimating negative electrode safety or a negative electrode safety estimation method S1000 according to one or more embodiments of the present disclosure; and

[0038] Figure 11 The illustration is a flowchart illustrating an example of the steps for estimating the negative electrode safety of at least one monomer according to one or more embodiments of the present disclosure. Detailed Implementation

[0039] In the accompanying drawings, the dimensions of layers and regions may be enlarged for clarity. It should also be understood that when a layer or element is referred to as "on" another layer or substrate, it can be directly on the other layer or substrate, or an intermediate layer may be present. Furthermore, it should be understood that when a layer is referred to as "below" another layer, it can be directly below the other layer, and one or more intermediate layers may be present. Additionally, it should be understood that when a layer is referred to as "between two layers," it can be the only layer between the two layers, or one or more intervening layers may be present. The same reference numerals refer to the same elements throughout the drawings.

[0040] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims are not to be construed as having their usual or dictionary meanings, but should be interpreted as having meanings and concepts consistent with the technical spirit of the present disclosure, based on the principle that the inventor can be his / her own lexicographer to appropriately define the concepts of the terms to best describe his / her invention.

[0041] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some embodiments of this disclosure and do not represent all the technical spirit, aspects, and features of this disclosure. Accordingly, it should be understood that various equivalents and modifications may exist to replace or modify the embodiments described herein at the time of filing this application.

[0042] It should be understood that when an element or layer is described as being "on" another element or layer, "connected to," or "linked to" another element or layer, it may be directly on, directly connected to, or directly linked to that other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is described as being "directly on" another element or layer, "directly connected to," or "directly linked to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "linked" or "connected" to a second element, the first element may be directly linked or directly connected to the second element, or the first element may be indirectly linked or indirectly connected to the second element via one or more intermediary elements.

[0043] In the figures, the dimensions of various elements, layers, etc., may be enlarged for clarity. The same reference numerals label the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated enumerated items. Furthermore, in describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” When expressions such as “at least one of…” and “any one of…” follow a list of elements, they modify the entire list of elements and not individual elements within the list. When phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one selected from the group of A, B, and C,” or “at least one selected from A, B, and C” are used to refer to a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term “use” and its variations may be considered synonymous with the term “utilize” and its variations, respectively. As used herein, the terms “substantially,” “approximately,” and similar terms are used as approximate terms and not as terms of degree, and are intended to explain the inherent variations in the measured or calculated values ​​that will be recognized by those skilled in the art.

[0044] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, first component, first region, first layer, or first portion discussed below may be referred to as a second element, second component, second region, second layer, or second portion.

[0045] For ease of description, spatial relative terms such as “below,” “below,” “down,” “above,” and “above” are used herein to describe the relationship between one element or feature and another illustrated in the figures. It should be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “below” or “below” other elements or features will be oriented “above” or “above” that other element or feature. Therefore, the term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein should be interpreted accordingly.

[0046] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that when the terms “comprising,” “including,” and variations thereof are used in this specification, the term specifies the presence of the described features, numbers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or groups thereof.

[0047] Furthermore, any numerical range disclosed and / or referenced herein is intended to include all subranges with the same numerical precision contained within the referenced range. For example, the range “1.0 to 10.0” is intended to include all subranges between the stated minimum value of 1.0 and the stated maximum value of 10.0 (and inclusive of both), i.e., minimum values ​​greater than or equal to 1.0 and maximum values ​​less than or equal to 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits contained therein, and all minimum numerical limits set forth in this specification are intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to amend this specification (including the claims) to expressly set forth any subranges contained within the range expressly set forth herein. All such ranges are intended to be inherently described in this specification such that any amendment to expressly set forth any such subrange will comply with the requirements of Chinese Patent Law.

[0048] Referring to two compared elements, features, etc., as “identical” can mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with deviations considered low in the art (e.g., 5% or less). Additionally, when a parameter is said to be uniform over a given region, this can mean that it is uniform in terms of average value.

[0049] Throughout the instruction manual, unless otherwise stated, each element may be singular or plural.

[0050] Placing any element "above (or below)" or "above (below)" another element can mean that the arbitrary element can be configured to contact the upper (or lower) surface of the element, and the other element can also be located between the element and any element disposed on (or below) the element.

[0051] Additionally, it should be understood that when a component is referred to as a “link,” “connect,” or “attached” to another component, these components can be directly “connected,” “linked,” or “attached” to each other, or another component can “intervene” between these components.

[0052] Throughout the specification, unless otherwise stated, when “A and / or B” is mentioned, it means A, B, or A and B. That is, “and / or” includes any or all combinations of the listed items. Unless otherwise stated, when “C to D” is mentioned, it means C or greater and D or less.

[0053] Figure 1The illustration shows a conceptual view of a battery system 120 according to one or more embodiments of the present disclosure. A single cell 110 (also referred to as a "battery cell") can be charged by a charger 130. For example, the single cell 110 can be disposed in an electronic device and can be charged by a charger included in the electronic device or an external charger. Reference Figure 1 The cell 110 is shown connected only to the charger 130 and the battery system 120, but this disclosure is not limited thereto. For example, the cell 110 may be electrically connected to an external configuration. The cell 110 may provide power to the external configuration while being charged, or it may provide power to the external configuration after charging is complete. In another example, the cell 110 may be electrically connected to another external configuration after being disconnected from the battery system 120 and the charger 130.

[0054] Charger 130 can charge cell 110 by changing the charging rate (C-rate). In this document, the charging rate can be the magnitude of the battery's charging current divided by the battery's rated capacity. For example, charger 130 can charge cell 110 at a first charging rate and a second charging rate different from the first charging rate. For example, the first charging rate can be slower than the second charging rate.

[0055] In an implementation, the second charging rate may be equal to or lower than a predetermined threshold. For example, the threshold may be 0.33C or lower, where C is a unit of charging rate, which may refer to the charging rate at which a certain amount of time (e.g., 10 hours) is spent fully charging the corresponding cell.

[0056] The battery system 120 may include a voltage sensor 122 and a controller 124. When the cell 110 is being charged by the charger 130, the voltage sensor 122 may generate charging data about the cell 110. The generated charging data may be transmitted to the controller 124.

[0057] The controller 124 can receive generated charging data from the voltage sensor 122. The charging data may include charging voltage data based on the charging capacity obtained by charging the cell 110. The controller 124 can calculate differential voltage data based on the charging voltage data. The controller 124 can calculate the peak charging capacity based on the charging voltage data. In embodiments, the charging data may include differential voltage data, and the differential voltage data may include the peak charging capacity. In the following description, the controller 124 will be interpreted as calculating differential voltage data based on the charging voltage data included in the charging data, and calculating the peak charging capacity based on the charging voltage data, but is not limited thereto. For example, at least one processor included in the battery system 120 can calculate the differential voltage data and calculate the peak charging capacity.

[0058] In this implementation, charging data can be obtained by charging the cell 110 to a fully charged state. The charging data can include the charging capacity of the cell 110 in a fully charged state, which is obtained by charging the cell 110 to a fully charged state. Alternatively, charging data can be obtained by charging the cell 110 when its state is below a SoC threshold. For example, the SoC threshold can be a value included in the range of 0 to 40%. For example, the SoC threshold can be 25%. However, the SoC threshold is not limited to this and can be a predetermined value. Any suitable value can be used as the SoC threshold to obtain sufficient charging data.

[0059] In this embodiment, cell 110 may be a battery cell in a mid-life (MoL) state. Cell 110 may be a battery whose lifespan has been reduced due to repeated charging and discharging. For example, the state of health (SoH) of cell 110 may be about 99% or lower. However, this is not intended to be limiting, and cell 110 may be a cell that has been charged and discharged once or multiple times immediately after manufacturing.

[0060] In another embodiment, cell 110 may be a battery cell in the early life (BoL) state. Cell 110 may be a newly manufactured battery. For example, the SoH of cell 110 may be approximately 100%. In another embodiment, cell 110 may be a battery whose voltage is first measured by voltage sensor 122. That is, cell 110 may be in a state before its life is reduced by charger 130.

[0061] In one embodiment, the first charging data may include first charging voltage data based on the charging capacity obtained by charging the cell 110 (e.g., cell 110 in a MoL state) at a first charging rate. Furthermore, the second charging data may include second charging voltage data based on the charging capacity obtained by charging the cell 110 (e.g., cell 110 in a MoL state) at a second charging rate. Additionally, the third charging data may include third charging voltage data based on the charging capacity obtained by charging the cell 110 (e.g., cell 110 in a BoL state).

[0062] In one implementation, controller 124 can calculate negative electrode health based on peak charging capacity. Additionally, controller 124 can calculate reference negative electrode health based on peak charging capacity associated with BoL. Based on the negative electrode health and the reference negative electrode health, controller 124 can estimate the negative electrode safety of cell 110.

[0063] Charger 130 and controller 124 can communicate with each other. Additionally, controller 124 can adjust the charging rate of charger 130. In one embodiment, controller 124 can adjust the upper limit of the charging rate of cell 110 based on negative electrode safety. For example, in response to controller 124 determining that the negative electrode safety is below a safety threshold, the upper limit of the charging rate of cell 110 charged by charger 130 can be reduced.

[0064] refer to Figure 1 A single cell 110 is shown, but this is not intended to be limiting. For example, multiple cells can be charged by charger 130, and charging data can be generated by voltage sensor 122. In one embodiment, the cell can be a battery cell in a BoL state. In another embodiment, the cell can be a battery cell in a MoL state that has been charged and discharged at least once in the BoL state.

[0065] As the monomer 110 is repeatedly charged and discharged, its lifetime may decrease. Specifically, as the monomer 110 is repeatedly charged and discharged, the negative electrode included in the monomer 110 may degrade. The more the negative electrode of the monomer degrades, the greater the risk of lithium plating. As those skilled in the art know, lithium plating occurs when metallic lithium is deposited on the surface of the negative electrode rather than inserted into the negative electrode material via an intercalation layer. Furthermore, the faster the charge rate of the monomer, the greater the risk of lithium plating. (See reference...) Figure 3 Provide a detailed description of this.

[0066] As described above, the method for estimating negative electrode safety according to this disclosure can estimate the negative electrode safety of monomer 110, and the charging rate of monomer 110 can be adjusted by comparing the negative electrode safety with a predetermined threshold. The adjusted (e.g., reduced) charging rate can reduce the risk of lithium plating in monomer 110. In addition, the adjusted charging rate can reduce the rate of negative electrode degradation that occurs when monomer 110 is repeatedly charged and discharged, and can slow down the rate of decline in the lifetime of monomer 110.

[0067] Figure 2 The diagram illustrates a block diagram of the internal configuration of a controller 200 according to one or more embodiments of the present disclosure; the controller 200 may include a charging data receiver 210, a negative electrode health calculator 220, a reference negative electrode health calculator 230, a negative electrode safety estimator 240, and a charging rate regulator 250. For example, the controller 200 may be included in Figure 1 The controller 124 in the battery system 120.

[0068] The charging data receiver 210 can receive data from a voltage sensor (e.g., Figure 1The voltage sensor 122) receives charging data. For example, the charging data receiver 210 can receive first charging data associated with a first charging rate and second charging data associated with a second charging rate from the voltage sensor. Additionally, the charging data receiver 210 can receive data associated with at least one individual (e.g., Figure 1 The third charging data associated with the BoL of the single cell (110).

[0069] In one implementation, the first charging data may include first charging voltage data based on the charging capacity obtained by charging at least one cell at a first charging rate. The second charging data may include second charging voltage data based on the charging capacity obtained by charging at least one cell at a second charging rate. The third charging data may include third charging voltage data based on the charging capacity obtained by charging at least one cell in a BoL state.

[0070] In an implementation, the method may include calculating differential voltage data of the charging voltage data included in the charging data. For example, the negative electrode health calculator 220 can calculate differential voltage data of the charging voltage data included in the charging data. Specifically, the negative electrode health calculator 220 can derive differential voltage data of the charging voltage data by differentiating the charging voltage data. For example, the negative electrode health calculator 220 can calculate first differential voltage data of first charging voltage data and second differential voltage data of second charging voltage data.

[0071] The negative electrode health calculator 220 can calculate peak charging capacity based on charging voltage data. For example, the negative electrode health calculator 220 can obtain the first peak charging capacity and the first peak charging capacity from the first differential voltage data calculated based on the first charging voltage data. (See reference...) Figures 3 to 7 Provide a detailed description of the peak charging capacity.

[0072] In one implementation, the negative electrode health calculator 220 can calculate the negative electrode health of at least one cell based on first charging data and second charging data. For example, the negative electrode health can be calculated based on the peak charging capacity associated with the first charging data and the peak charging capacity associated with the second charging data. (See reference...) Figure 6 and Figure 7 Describe in detail the process of calculating the health of the negative electrode based on peak charging capacity.

[0073] In an implementation, similar to the negative electrode health calculator 220, a third differential voltage data of the third charging data associated with the BoL of at least one cell can be calculated. Additionally, the reference negative electrode health calculator 230 can calculate a third-first peak charging capacity and a third-second peak charging capacity based on the third charging voltage data. The reference negative electrode health calculator 230 can calculate the reference negative electrode health based on the third-first peak charging capacity and the third-second peak charging capacity.

[0074] In an implementation, in response to charging at least one cell until the cell reaches a fully charged state, a voltage sensor (e.g., Figure 1 The voltage sensor 122 can obtain the charging capacity in a fully charged state (hereinafter referred to as "full charge capacity"). Charging data can include the full charge capacity, and the charging data receiver 210 can receive charging data including the full charge capacity. The negative electrode health calculator 220 can calculate the negative electrode health of at least one cell based on the full charge capacity of at least one cell in the MoL state and the peak capacity associated with the MoL of at least one cell. Similarly, the reference negative electrode health calculator 230 can calculate the reference negative electrode health of at least one cell based on the full charge capacity of at least one cell in the BoL state and the peak capacity associated with the BoL of at least one cell.

[0075] In this implementation, the negative electrode safety estimator 240 can estimate negative electrode safety based on negative electrode health and a reference negative electrode health. Specifically, the negative electrode safety estimator 240 can estimate negative electrode safety by comparing negative electrode health with a reference negative electrode health. For example, negative electrode safety can be equal to negative electrode health divided by reference negative electrode health. Figure 6 and Figure 7 Describe in detail the specific process for calculating the safety of the negative electrode.

[0076] In one implementation, the charging rate regulator 250 can adjust the charging rate of a charger charging at least one individual cell based on negative electrode safety. For example, the charging rate regulator 250 can determine whether the estimated negative electrode safety is below a safety threshold. In response to determining that the estimated negative electrode safety is below the safety threshold, the charging rate regulator 250 can reduce the upper limit of the charging rate of the charger. For example, the safety threshold can be approximately 80%. If the estimated negative electrode safety is less than 80%, the charging rate regulator 250 can reduce the upper limit of the charging rate (or the charging rate) so that the negative electrode stability is greater than or equal to 80%.

[0077] In one implementation, controller 200 may include a memory and a processor. The memory may include any non-transitory computer-readable recording medium. According to one implementation, the memory may include a non-transitory permanent mass storage device such as random access memory (RAM), read-only memory (ROM), a disk drive, a solid-state drive (SSD), or flash memory. In another example, a non-transitory mass storage device such as ROM, SSD, flash memory, or disk drive may be included in controller 200 as a separate permanent storage device, distinct from the memory. Additionally, the memory may store an operating system and at least one program code (e.g., code installed and executed on controller 200 to, for example, estimate negative electrode safety).

[0078] The processor can be configured to process instructions from a computer program by performing basic arithmetic, logic, and input / output operations. Instructions can be provided to the charger (e.g., via memory or a communication module) Figure 1 The processor can be a charger 130), an external device, or another external system. For example, the processor can calculate differential voltage data based on the charging voltage data. The processor can calculate peak charging capacity based on the charging voltage data. The processor can estimate negative electrode safety based on the charging data.

[0079] Additionally, the controller 200 may further include a communication module. The communication module can provide configuration or functions for communicating with the charger, and can also provide configuration and functions for the controller 200 to communicate with external devices and systems. For example, control signals, commands, and data provided under the control of the processor of the controller 200 can be transmitted to the charger, external devices, and / or external systems via the communication module.

[0080] Figure 3 The illustration shows an example of charging voltage data for a negative electrode half-cell according to one or more embodiments of this disclosure. In this document, the negative electrode half-cell may be a button cell comprising graphite as the negative electrode. The negative electrode half-cell may have a maximum charging capacity of 2.4 Ah. The negative electrode half-cell may be a half-cell in the BoL state before the charging voltage data is generated. For example, the negative electrode half-cell may have undergone a formation process including two charge and discharge operations at a charging rate of 0.05C. In this document, a negative electrode half-cell may refer to a single cell comprising only a negative electrode and excluding a positive electrode.

[0081] Figure 3The graph is an example of charging voltage data based on charging capacity obtained by charging the negative electrode half-cell. Specifically, multiple charging voltage data points 310, 320, and 330 can be obtained by changing the charging rate. For example, the first charging voltage data point 310 could be based on charging voltage data of the charging capacity obtained by charging the negative electrode half-cell at a charging rate of 0.1C. The second charging voltage data point 320 could be based on charging voltage data of the charging capacity obtained by charging the negative electrode half-cell at a charging rate between 0.1C and 1C. The third charging voltage data point 330 could be based on charging voltage data of the charging capacity obtained by charging at a charging rate of 1C. (Reference) Figure 3 The charging rate associated with the charging voltage data can be faster in direction A.

[0082] The negative electrode half-cell can be charged to a predetermined voltage of not less than 0V. (Reference) Figure 3 This shows that the negative electrode half-cell is charged to a predetermined voltage. The negative electrode included in a full cell is configured to charge to 0V or lower, but due to the characteristics of a half-cell, it may not be charged to 0V. In this context, a full cell can refer to a single cell containing both a positive and a negative electrode.

[0083] In the first charging voltage data 310, the full charge capacity can be equal to or closest to the maximum charging capacity of the negative electrode half-cell. For example, in the first charging voltage data 310, the full charge capacity can be approximately 2.4 Ah. The full charge capacity of the second charging voltage data 320 and the full charge capacity of the third charging voltage data 330 can be less than the full charge capacity of the first charging voltage data 310.

[0084] In this case, the greater the difference between the full charge capacity of the nth charging voltage data (where n is a natural number greater than or equal to 2) and the full charge capacity of the first charging voltage data 310, the greater the risk of lithium plating on the negative electrode of the cell charged at the charging rate associated with the nth charging voltage data. For example, the difference D2 between the full charge capacity of the third charging voltage data and the full charge capacity of the first charging voltage data can be greater than the difference D1 between the full charge capacity of the second charging voltage data and the full charge capacity of the first charging voltage data. In this case, the cell charged at the charging rate associated with the third charging voltage data may be at a greater risk of lithium plating than the cell charged at the charging rate associated with the second charging voltage data. In this paper, the difference between the full charge capacity of the nth charging voltage data and the full charge capacity of the first charging voltage data 310 can be referred to as the length of the lithium plating risk zone.

[0085] Figure 4The illustration shows an example of differential voltage data for a negative electrode half-cell according to one or more embodiments of the present disclosure. Specifically, Figure 4 Can be illustrated Figure 3 The differential voltage data from charging voltage data 310 to charging voltage data 330 shown are illustrated.

[0086] refer to Figure 4 The charging rate associated with the differential voltage data can increase in direction A. For example, the charging rate of the negative electrode half-cell corresponding to the first differential voltage data 410 can be slower than the charging rate of the negative electrode half-cell corresponding to the second differential voltage data 420. For example, the charging rate of the negative electrode half-cell corresponding to the first differential voltage data 410 can be 0.1C. Conversely, the charging rate of the negative electrode half-cell corresponding to the second differential voltage data 420 can be 1C.

[0087] Each of the differential voltage data may include multiple peaks. For example, the Tth differential voltage data included in the differential voltage data may include a T_1th peak and a T_2th peak (e.g., where T is a natural number greater than or equal to 1). In this case, the T_1th peak may include the T_1th peak charging capacity, which is the charging capacity corresponding to the T_1th peak. The T_2th peak may include the T_2th peak charging capacity, which is the charging capacity corresponding to the T_2th peak.

[0088] refer to Figure 4 In the region where the charging capacity is less than 0.5Ah, peak values ​​can be generated for each individual differential voltage data point. (Reference) Figure 4 The downward bulge in the curve can correspond to peak values. However, this is not intended to be limiting, and when the differential voltage data is expressed in absolute values, the upward bulge in the curve can also correspond to peak values. These peak values ​​can be associated with the T_1-th peak value of each of the differential voltage data. (See reference...) Figure 4 In the region where the charging capacity is between 1.0Ah and 1.5Ah, a peak can be formed for each of the differential voltage data. For each of the differential voltage data, the peak can be associated with the T_2 peak.

[0089] In this implementation, the peak charging capacity of T_1 can be included in the first charging region. The peak charging capacity of T_2 can be included in the second charging region. The first charging region can be defined as including 25% of the charging capacity of the SoC of the unit under test. For example, the first charging region can be a region where the SoC of the unit under test is between 15% and 35%. The second charging region can be defined as including 50% of the charging capacity of the SoC of the unit under test. For example, the second charging region can be a region where the SoC of the unit under test is between 40% and 60%.

[0090] In one implementation, when multiple peaks of a single differential voltage data point are generated in a single charging region, the peak value corresponding to the peak charging capacity closest to a reference value for that charging region can be selected. For example, the reference value for the first charging region could be 25% of the value of the cell under test. The reference value for the second charging region could be 50% of the value of the cell under test.

[0091] refer to Figure 4 The first differential voltage data 410 may include a first peak value (not shown) and a first peak value 412. The first peak value 412 may include the first peak charging capacity. The second differential voltage data 420 may include a second peak value (not shown) and a second peak value 422. The second peak value 422 may include the second peak charging capacity. In the example, the charging rate corresponding to the first differential voltage data 410 may be slower than the charging rate corresponding to the second differential voltage data 420. In this case, the first peak charging capacity may be higher than the second peak charging capacity. Therefore, as the charging rate increases, the second peak value appearing in the differential voltage data may shift to the left. In this document, the peak offset may be defined as the first peak charging capacity minus the nth peak charging capacity, where n is a natural number greater than or equal to 2.

[0092] In MoL batteries, the T_2 peak value may shift with increasing charging rate. On the other hand, this shift in the T_2 peak value may not occur in BoL batteries. In another example, the degree of T_2 peak value shift in BoL batteries can be relatively smaller than in MoL batteries. As a result, the T_2 peak value shift observed in BoL batteries can be negligible.

[0093] Figure 5 The figure shows a graph illustrating an example relationship between the peak charge capacity of a negative electrode half-cell and the length of the lithium plating risk region, according to one or more embodiments of the present disclosure. Figure 5 The Y-axis can represent a reference. Figure 3 The length of the lithium plating risk region described in the charging voltage data of the negative electrode half-cell. Figure 5 The X-axis can represent the reference. Figure 4 The peak charging capacity at T_2 of the differential voltage data of the negative electrode half-cell is described.

[0094] The first data 510 can be compared with Figure 3 The first charging voltage data 310 is associated with, and simultaneously with Figure 4 The first differential voltage data 410 is associated with it. That is, Figure 4 The first differential voltage data 410 can be relative to Figure 3The derivative of the first charging voltage data 310. The length of the lithium plating danger zone included in the first data 510 can be approximately 0 Ah, and the peak charging capacity included in the first data 510 can be approximately 1.2 Ah.

[0095] The second data 520 can be compared with... Figure 3 The second charging voltage data 320 is associated with, and simultaneously with Figure 4 The second differential voltage data 420 is associated with this. That is, Figure 4 The second differential voltage data 420 can be relative to Figure 3 The derivative of the second charging voltage data 320. The length of the lithium plating danger zone included in the second data 520 can be approximately 0.73 Ah, and the peak charging capacity included in the second data 520 can be approximately 1.05 Ah.

[0096] Figure 5 The data shown can be related to the charging rate. For example, the charging rate for each data point can increase in direction B. For instance, the charging rate corresponding to the first data point 510 can be slower than the charging rate corresponding to the second data point 520.

[0097] refer to Figure 5 Peak charging capacity may decrease with increasing charging rate. As peak charging capacity decreases, the length of the lithium plating risk zone may increase. In other words, referencing Figure 4 The greater the peak offset described, the greater the risk of lithium plating. Furthermore, the risk of lithium plating may increase with increasing charging rate. Therefore, it may be desirable to adjust the charging rate of the individual cells to prevent lithium plating.

[0098] Figure 6 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure. Figure 7 The illustration is a graph showing an example of differential voltage data of a full cell according to one or more embodiments of the present disclosure. Figure 6 and Figure 7 The curve in the graph can show the differential voltage data in absolute value.

[0099] A full cell can be a single cell that includes both a positive electrode and a negative electrode. The positive electrode of a full cell may include NCA with 88% Ni, and the negative electrode may include graphite and silicon. Figure 6 and Figure 7 In this context, MoL can refer to the state immediately after manufacturing, where 60 charge-discharge cycles have been performed, charging at a rate of 3C and discharging at a rate of 0.5C. The maximum capacity of the full battery can be approximately 3Ah.

[0100] The first charging voltage data may include the charging capacity obtained by charging the full cell in the MoL state at a first charging rate (e.g., 0.05C). The first differential voltage data 610 may be a derivative of the first charging voltage data. The first charging voltage data may include the fully charged capacity 616 of the full cell in the MoL state.

[0101] The second charging voltage data may include the charging capacity obtained by charging a full battery in the MoL state at a second charging rate (e.g., 0.2C). The second differential voltage data 620 may be a derivative of the second charging voltage data.

[0102] The third charging voltage data may include the charging capacity obtained by charging a full battery in the BoL state at a first charging rate (e.g., 0.05C). The third differential voltage data 630 may be a derivative of the third charging voltage data. The third charging voltage data may include the full charge capacity 636.

[0103] The fourth charging voltage data may include the charging capacity obtained by charging a full battery in the BoL state at a second charging rate (e.g., 0.2C). The fourth differential voltage data 640 may be a derivative of the fourth charging voltage data.

[0104] The first differential voltage data 610 may include a first peak value and a second peak value. The first differential voltage data 610 may include a first peak value charging capacity 612 with respect to the first peak value and a second peak value charging capacity 614 with respect to the second peak value.

[0105] The second differential voltage data 620 may include a second-first peak value and a second-second peak value. The second differential voltage data 620 may include a second-first peak charging capacity with respect to the second-first peak value and a second-second peak charging capacity with respect to the second-second peak value.

[0106] Peak 1 and peak 2 can be included in a first charging region. For example, the first charging region can be a region where the SoC of the device under test is 20% to 30%. Additionally, peak 1 and peak 2 can be included in a second charging region. For example, the second charging region can be a region where the SoC of the device under test is 45% to 55%.

[0107] Negative electrode health can be correlated with a full cell in the MoL state. Negative electrode health can be calculated based on the first-1 peak charge capacity 612, the first-2 peak charge capacity 614, the second-2 peak charge capacity 622, and the full charge capacity 616 of a full cell in the MoL state. Specifically, negative electrode health can be calculated using Equation 1 below.

[0108] [Equation 1]

[0109] Negative electrode health = (βX1 - Y1) - αΔX

[0110] In Equation 1 above, X1 can be the first-second peak charge capacity 614 minus the first-first peak charge capacity 612. Y1 can be the full charge capacity 616 of the full cell in the MoL state minus the first-first peak charge capacity 612. ΔX can be the amount of peak change, i.e., the first-second peak charge capacity minus the second-second peak charge capacity. Further, α can be a first proportionality constant that varies with the difference between the first charging rate and the second charging rate, and β can be a second proportionality constant that varies with the negative electrode material. For example, in the case where the negative electrode includes graphite, β can be approximately 3.

[0111] Regarding negative electrode health, (βX1-Y1) can be associated with an increase in the resistance of the negative electrode. Regarding negative electrode health, αΔX can be associated with a decrease in the capacity of the negative electrode. The decrease in the capacity of the negative electrode can be related to the degree of lithium plating, and αΔX can also be related to the degree of lithium plating. That is, the lower the calculated negative electrode health, the greater the increase in the resistance of the negative electrode of the cell. Furthermore, the lower the calculated negative electrode health, the less the decrease in the capacity of the negative electrode of the cell.

[0112] The third differential voltage data 630 may include the 3_1 peak value and the 3_2 peak value. The third differential voltage data 630 may include the 3_1 peak value charging capacity 632 with respect to the 3_1 peak value and the 3_2 peak value charging capacity 634 with respect to the 3_2 peak value.

[0113] The fourth differential voltage data 640 may include the 4_1 peak value and the 4_2 peak value. The fourth differential voltage data 640 may include the 4_1 peak charging capacity with respect to the 4_1 peak value and the 4_2 peak charging capacity with respect to the 4_2 peak value.

[0114] Peak values ​​3_1 and 4_1 can be included in the first charging region. Additionally, peak values ​​3_2 and 4_2 can be included in the second charging region. The charging capacity of peak value 3_1 can be the same as or similar to that of peak value 4_1. Similarly, the charging capacity of peak values ​​3_2 and 4_2 can be the same as or similar. That is, a full cell in the BoL state may not experience any negative electrode degradation and therefore has no peak shift and / or peak variation. In another example, even if negative electrode degradation occurs, a full cell in the BoL state can have very small peak shift and / or peak variation. In this structure, the peak shift and / or peak variation of a full cell in the BoL state can be negligible.

[0115] The reference negative electrode health can be correlated with a full cell in the BoL state. The reference negative electrode health can be calculated based on the 3_1 peak charge capacity 632, the 3_2 peak charge capacity 634, and the fully charged capacity 636 of a full cell in the BoL state. Specifically, the reference negative electrode health can be calculated using Equation 2 below.

[0116] [Equation 2]

[0117] Reference negative electrode health = βX2 - Y2

[0118] In Equation 2 above, X2 can be the third-second peak charging capacity 634 minus the third-first peak charging capacity 632. Y2 can be the full charge capacity of the full battery in BoL state 636 minus the third-first peak charging capacity 632.

[0119] Negative electrode safety can be calculated based on negative electrode health and a reference negative electrode health. Specifically, negative electrode safety can be calculated by comparing negative electrode health and a reference negative electrode health. For example, negative electrode safety can be negative electrode health / reference negative electrode health multiplied by 100: Negative electrode safety (%) = (negative electrode health) / (reference negative electrode health) x 100. In other words, negative electrode safety can be calculated as shown in Equation 3 below.

[0120] [Equation 3]

[0121]

[0122] Negative electrode safety can be calculated by comparing a reference negative electrode health associated with a cell in the BoL state with the negative electrode health associated with a cell in the MoL state. Negative electrode safety can represent the degree of increase in the resistance and decrease in the capacity of the negative electrode of the cell being estimated (e.g., a cell in the MoL state). In other words, the higher the negative electrode safety, the safer the cell can be considered to have that level of negative electrode safety.

[0123] As stated above, negative electrode safety can serve as a reference for determining the degree of capacity reduction and resistance increase of the negative electrode. Because negative electrode degradation reduces its capacity and increases its resistance, negative electrode safety is a better indicator of the degree of degradation. Furthermore, the use of the method for estimating negative electrode safety according to this disclosure is facilitated by the fact that the condition of the negative electrode can be determined using data from a fully charged battery.

[0124] Figure 8The illustration is a graph showing example differential voltage data of a full cell according to one or more embodiments of the present disclosure. In addition to including LFP (lithium iron phosphate, e.g., LiFePO4) as the positive electrode, a full cell according to another embodiment can be compared with a reference... Figure 7 The descriptions of the full cells are the same. Different materials may result in differences in the maximum capacity, etc., of the full cells.

[0125] The first charging voltage data may include the charging capacity obtained by charging a full battery in the MoL state at a first charging rate (e.g., 0.05C). The first differential voltage data 810 may be a derivative of the first charging voltage data. The second charging voltage data may include the charging capacity obtained by charging a full battery in the MoL state at a second charging rate (e.g., 0.33C). The second differential voltage data 820 may be a derivative of the second charging voltage data.

[0126] The first differential voltage data 810 may include a first peak value. The first differential voltage data 810 may include a first peak charging capacity 812 with respect to the first peak value. The second differential voltage data 820 may include a second peak value. The second differential voltage data 820 may include a second peak charging capacity 822 with respect to the second peak value. In this document, the first peak value and the second peak value may be included in a charging region (e.g., a region of 45% to 55% of the SoC of the cell under test).

[0127] refer to Figure 8 The faster the charging rate, the lower the peak charging capacity may be. Specifically, the first peak charging capacity 812 may be higher than the second peak charging capacity 822. That is, the amount of peak change ΔX may occur with changes in the charging rate, and the peak may shift as the charging rate becomes faster.

[0128] Figure 9 The illustration is a graph showing example differential voltage data of a full cell according to one or more embodiments of the present disclosure. In addition to including NCM622 (lithium nickel manganese cobalt oxide 622, wherein 622 indicates a nickel, cobalt, and manganese ratio of 6:2:2) as the positive electrode, the full cell according to another embodiment can be compared with a reference... Figure 7 The descriptions of the full cells are the same. Different materials may result in differences in the maximum capacity, etc., of the full cells.

[0129] The first charging voltage data may include the charging capacity obtained by charging a full battery in the MoL state at a first charging rate (e.g., 0.05C). The first differential voltage data 910 may be a derivative of the first charging voltage data. The second charging voltage data may include the charging capacity obtained by charging a full battery in the MoL state at a second charging rate (e.g., 0.33C). The second differential voltage data 920 may be a derivative of the second charging voltage data.

[0130] The first differential voltage data 910 may include a first peak value. The first differential voltage data 910 may include a first peak charging capacity 912 with respect to the first peak value. The second differential voltage data 920 may include a second peak value. The second differential voltage data 920 may include a second peak charging capacity 922 with respect to the second peak value. In this document, the first peak value and the second peak value may be included in a charging region (e.g., a region of 45% to 55% of the SoC of the cell under test).

[0131] refer to Figure 9 The faster the charging rate, the lower the peak charging capacity may be. Specifically, the first peak charging capacity 912 can be higher than the second peak charging capacity 922. That is, the amount of peak change ΔX may occur with changes in the charging rate, and the peak may shift as the charging rate becomes faster.

[0132] For reference Figure 8 and Figure 9 As stated, peak values ​​may vary depending on the material of the positive electrode. The method for estimating the safety of the negative electrode according to this disclosure can be applied to individual battery cells, regardless of the material of the positive electrode. Accordingly, the method for estimating the safety of the negative electrode according to this disclosure can have greater versatility for secondary batteries.

[0133] Figure 10 The illustration is a flowchart illustrating an example of a method for estimating negative electrode safety or a negative electrode safety estimation method S1000 according to one or more embodiments of the present disclosure. The negative electrode safety estimation method S1000 can be performed by a battery system. In this document, the battery system may include a voltage sensor and a controller. The controller may include at least one processor. The voltage sensor can measure the voltage of at least one cell based on its charge capacity.

[0134] First, the negative electrode safety estimation method S1000 may begin (e.g., by at least one processor) by receiving first charging data about at least one cell from a voltage sensor (step S1010).

[0135] In this implementation, the controller (or at least one processor) can receive second charging data about at least one cell from a voltage sensor (step S1020). Hereinafter, the first and second charging data can be generated by charging at least one cell when the state of charge (SoC) of at least one cell is below the SoC threshold.

[0136] In an implementation, the first charging data may include first charging voltage data based on the charging capacity obtained by charging at least one individual at a first charging rate, and the second charging data may include second charging voltage data based on the charging capacity obtained by charging at least one individual at a second charging rate.

[0137] In this implementation, the controller can estimate the negative electrode safety of at least one cell based on first charging data and second charging data. Herein, negative electrode safety can be associated with a decrease in the capacity of the negative electrode and an increase in its resistance. For example, the first charging data and the second charging data can have different charging rates (C-rate). Furthermore, the first charging rate can be slower than the second charging rate, and the second charging rate can be equal to or lower than a predetermined threshold.

[0138] In this implementation, the controller can calculate a first differential voltage data of the first charging voltage data. Additionally, the controller can calculate a second differential voltage data of the second charging voltage data.

[0139] In this implementation, the first differential voltage data may include a first peak charging capacity and a second peak charging capacity, and the second differential voltage data may include a second peak charging capacity. Hereinafter, the first peak charging capacity may be included in a first charging region, and the first second peak charging capacity and the second peak charging capacity may be included in a second charging region.

[0140] In an implementation, the safety of the negative electrode can be estimated (e.g., by a controller) based on the first-first peak charging capacity, the first-second peak charging capacity, and the second peak charging capacity. For example, the amount of peak variation can be calculated (e.g., by a controller) based on the first-second peak charging capacity and the second peak charging capacity. Additionally, the safety of the negative electrode can be estimated (e.g., by a controller) based on the amount of peak variation, the first-first peak charging capacity, and the first-second peak charging capacity.

[0141] In an implementation, at least one cell is a lithium secondary battery, and the amount of peak variation can be correlated with the degree of lithium plating on the negative electrode included in at least one cell.

[0142] In an implementation, third charging data associated with the BoL of at least one unit may be received (e.g., by a controller) (step S1030).

[0143] In one implementation, the controller can estimate the negative electrode safety of at least one cell based on the first to third charging data (step S1040).

[0144] In one implementation, the controller may adjust the upper limit of the charging rate of at least one cell based on an estimated negative electrode safety (step S1050). Specifically, the controller may reduce the upper limit of the charging rate in response to determining that the negative electrode safety is below a safety threshold.

[0145] Figure 11 The illustration shows a flowchart illustrating an example of step S1040 for estimating the negative electrode safety of at least one cell according to one or more embodiments of the present disclosure. Step S1040 may begin by calculating differential voltage data based on charging voltage data (step S1110). In embodiments, first charging data may include first charging voltage data based on the charging capacity obtained by charging at least one cell at a first charging rate, second charging data may include second charging voltage data based on the charging capacity obtained by charging at least one cell at a second charging rate, and third charging data may include third charging voltage data based on the charging capacity obtained by charging at least one cell in a BoL state. Additionally, the controller may calculate first differential voltage data from the first charging voltage data. The controller may calculate second differential voltage data from the second charging voltage data. The controller may calculate third differential voltage data from the third charging voltage data.

[0146] In this implementation, the controller can calculate the peak charging capacity included in the differential voltage data (step S1120). For example, the first differential voltage data may include a first peak charging capacity and a first second peak charging capacity, the second differential voltage data may include a second peak charging capacity, and the third differential voltage data may include a third peak charging capacity and a third second peak charging capacity. The first and third peak charging capacities may be included in a first charging region, and the first, second, and third peak charging capacities may be included in a second charging region. The controller can calculate the first to third peak charging capacities.

[0147] In an implementation, the negative electrode health of at least one cell can be calculated (e.g., by a controller) based on the first charging data and the second charging data (step S1130).

[0148] In an implementation, a reference negative electrode health associated with the BoL of at least one cell can be calculated (step S1140) based on third charging data (e.g., by a controller).

[0149] In an implementation, negative electrode safety can be estimated (e.g., by a controller) based on negative electrode health and a reference negative electrode health (step S1150). For example, the negative electrode safety of at least one cell can be estimated (e.g., by a controller) based on peak charging capacity from the first_1st to the third_2nd peak charging capacity.

[0150] Additionally, the first charging data may include the full charge capacity associated with the first charging data. The negative electrode safety of at least one cell can be estimated (e.g., by the controller) based on the full charge capacity associated with the first charging data and the first-1st peak charge capacity to the third-2nd peak charge capacity.

[0151] According to various embodiments of this disclosure, the adjusted charging rate can reduce the risk of lithium plating in the cell. Furthermore, it can reduce the negative electrode degradation rate that occurs as the battery cell is repeatedly charged and discharged, and can reduce the rate of decline in battery cell lifespan.

[0152] According to various embodiments of this disclosure, negative electrode safety can serve as a reference for determining the degree of reduction in negative electrode capacity and the degree of increase in negative electrode resistance. Because negative electrode degradation reduces negative electrode capacity and increases negative electrode resistance, negative electrode safety can be a better indicator of the degree of negative electrode degradation.

[0153] According to various embodiments of this disclosure, considering that the state of the negative electrode can be determined using data about a full battery that is being charged, the method for estimating the safety of the negative electrode according to this disclosure can be readily used.

[0154] According to various embodiments of this disclosure, the method for estimating the safety of the negative electrode can be applied to a single battery cell, regardless of the material of the negative electrode. Accordingly, the method for estimating the safety of the negative electrode can be highly versatile for secondary batteries.

[0155] Figure 10 and Figure 11 The flowcharts and descriptions above are merely illustrations of this disclosure, but the scope of this disclosure is not limited to... Figure 10 and Figure 11 The flowchart and the above description are as follows. For example, one or more steps in the flowchart and the above description can be added / modified / deleted, the order of one or more steps can be changed, and one or more steps can be executed substantially simultaneously.

[0156] The goal is to non-destructively diagnose the internal condition of a battery to determine the state of negative electrode degradation. While charge and discharge voltage data can be used to diagnose the internal condition of a battery, it is difficult to separately determine negative electrode degradation and positive electrode degradation from these data. Furthermore, it may be difficult to use charge and discharge voltage data to determine negative electrode degradation that includes not only the effects of reduced negative electrode capacity but also the effects of increased negative electrode resistance.

[0157] Although this disclosure has been described with reference to the accompanying drawings illustrating embodiments and various aspects thereof, this disclosure is not limited thereto. Various modifications and variations can be made by those skilled in the art within the scope of this disclosure and the following claims and their equivalents.

[0158] Exemplary embodiments have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, as will be apparent to those skilled in the art at the time of filing this application, unless otherwise specifically indicated, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. A method for estimating the safety of a negative electrode, the method comprising: At least one processor receives first charging data about at least one cell from a voltage sensor; The at least one processor receives second charging data about the at least one cell from the voltage sensor; as well as The at least one processor estimates the negative electrode safety of the at least one individual cell based on the first charging data and the second charging data. The first charging data and the second charging data have different charging rates.

2. The method of claim 1, wherein the first charging data includes first charging voltage data based on the charging capacity obtained by charging the at least one cell at a first charging rate, and The second charging data includes second charging voltage data based on the charging capacity obtained by charging the at least one cell at a second charging rate.

3. The method of claim 2, wherein the first charging rate is slower than the second charging rate, and the second charging rate is equal to or lower than a predetermined threshold.

4. The method of claim 2, further comprising: Calculate the first differential voltage data of the first charging voltage data; as well as Calculate the second differential voltage data of the second charging voltage data.

5. The method according to claim 4, wherein: The first differential voltage data includes the first peak charging capacity and the second peak charging capacity. The second differential voltage data includes the second peak charging capacity. The first peak charging capacity is included in the first charging region, and The first and second peak charging capacities are included in the second charging region.

6. The method of claim 5, wherein estimating the negative electrode safety of the at least one cell comprises estimating the negative electrode safety based on the first_1 peak charge capacity, the first_2 peak charge capacity, and the second peak charge capacity.

7. The method of claim 5, wherein estimating the negative electrode safety of the at least one monomer comprises: The amount of peak change is calculated based on the first and second peak charging capacities and the second peak charging capacity; as well as The safety of the negative electrode is estimated based on the amount of peak change, the first-first peak charging capacity, and the first-second peak charging capacity.

8. The method according to claim 7, wherein: The at least one cell is a lithium secondary battery, and The amount of peak variation is related to the degree of lithium plating on the negative electrode included in at least one of the monomers.

9. The method of claim 1, wherein if the state of charge (SoC) of the at least one cell is below an SoC threshold, the first charging data and the second charging data are generated by charging the at least one cell.

10. The method of claim 1, further comprising receiving third charging data associated with the initial lifetime BoL of the at least one cell, The estimation of the negative electrode safety of the at least one cell includes estimating the negative electrode safety of the at least one cell based on first charging data to third charging data, wherein the first charging data to the third charging data includes the first charging data, the second charging data, and the third charging data.

11. The method of claim 10, wherein estimating the negative electrode safety of the at least one cell based on the first charging data to the third charging data comprises: The negative electrode health of the at least one individual is calculated based on the first charging data and the second charging data; The health of the reference negative electrode associated with the BoL of the at least one individual is calculated based on the third charging data; as well as The safety of the negative electrode is estimated based on the negative electrode health and the reference negative electrode health.

12. The method according to claim 10, wherein: The first charging data includes first charging voltage data based on the charging capacity obtained by charging the at least one individual cell at a first charging rate. The second charging data includes second charging voltage data based on the charging capacity obtained by charging the at least one cell at a second charging rate, and The third charging data includes third charging voltage data based on the charging capacity obtained by charging the at least one unit associated with the BoL. The method further includes: Calculate the first differential voltage data of the first charging voltage data; Calculate the second differential voltage data of the second charging voltage data; and Calculate the third differential voltage data of the third charging voltage data. in: The first differential voltage data includes the first peak charging capacity and the second peak charging capacity. The second differential voltage data includes the second peak charging capacity. The third differential voltage data includes the 3_1 peak charging capacity and the 3_2 peak charging capacity. The first_1 peak charging capacity and the third_1 peak charging capacity are included in the first charging region, and The first and second peak charging capacities, the second peak charging capacity, and the third and second peak charging capacities are included in the second charging region.

13. The method of claim 12, wherein estimating the negative electrode safety of the at least one cell based on the first charging data to the third charging data includes estimating the negative electrode safety of the at least one cell based on the first_1 peak charging capacity to the third_2 peak charging capacity, wherein the first_1 peak charging capacity to the third_2 peak charging capacity includes the first_1 peak charging capacity, the first_2 peak charging capacity, the second peak charging capacity, the third_1 peak charging capacity, and the third_2 peak charging capacity.

14. The method of claim 12, further comprising charging the at least one cell until the at least one cell is fully charged. in: The first charging data includes the full charging capacity associated with the first charging data, and Estimating the negative electrode safety of the at least one cell based on the first charging data to the third charging data includes estimating the negative electrode safety of the at least one cell based on the full charge capacity associated with the first charging data and the first-1st peak charge capacity to the third-2nd peak charge capacity.

15. The method according to any one of claims 1 to 14, wherein the safety of the negative electrode is associated with a decrease in the capacity of the negative electrode and an increase in the resistance of the negative electrode.

16. The method according to any one of claims 1 to 14, further comprising adjusting the upper limit of the charging rate of the at least one cell based on the estimated safety of the negative electrode.

17. The method of claim 16, wherein adjusting the upper limit of the charging rate of the at least one cell includes reducing the upper limit of the charging rate in response to determining that the safety of the negative electrode is below a safety threshold.

18. A battery system comprising: A voltage sensor is configured to measure the voltage of at least one cell based on its charge capacity. and The controller is configured to receive charging data generated by the voltage sensor and estimate the negative electrode safety of the at least one cell based on the charging data. The charging data includes first charging data and second charging data for the at least one cell, and The first charging data and the second charging data have different charging rates.

19. The battery system according to claim 18, wherein: The charging data further includes third charging data associated with the initial BoL of the lifespan of the at least one individual, and The controller is further configured to: The negative electrode health of the at least one individual is calculated based on the first charging data and the second charging data; The health of the reference negative electrode associated with the BoL of the at least one individual is calculated based on the third charging data; as well as The safety of the negative electrode is estimated based on the negative electrode health and the reference negative electrode health.

20. The battery system of claim 18 or 19, wherein the controller is further configured to adjust the upper limit of the charging rate of the at least one cell based on the estimated safety of the negative electrode.

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