Detection and Mitigation For Lithium Planting of Lithium Battery

Abstract

A method for detecting and suppressing lithium electrodeposition according to one embodiment of the present disclosure may include: a terminal voltage measurement step of measuring the terminal voltage of a lithium battery while charging the lithium battery with a charging current; a charging characteristic measurement step of dividing the terminal voltage into a plurality of voltage intervals and measuring the charging characteristic for each voltage interval; a charging characteristic comparison step of comparing the charging characteristics of the same voltage interval of a first charging cycle and a second charging cycle; and an electrodeposition determination step of determining lithium electrodeposition if the charging characteristic of the first charging cycle increases continuously in a single or plurality of voltage intervals compared to the charging characteristic of the second charging cycle.

Description

Technology Field

[0001] The present invention relates to a method for detecting and suppressing lithium electrodeposition in a lithium battery. Background Technology

[0002] The importance of lithium batteries is growing significantly due to the recent expansion of electric vehicles, energy storage systems (ESS), and portable electronic devices. Leveraging their advantages such as high energy density, long lifespan, fast charging speeds, and lightweight design, lithium batteries are used in various fields including electric vehicles, smartphones, and laptops; in particular, the demand for lithium batteries is surging alongside the adoption of electric vehicles. In response to this increased demand, research on lithium battery production and recycling technologies is also actively underway.

[0003] Lithium electrodeposition is a phenomenon that occurs during the battery charging process, referring to the deposition and stacking of lithium metal on the negative electrode. This can shorten the lifespan of lithium batteries and compromise their safety. For example, if lithium electrodeposition occurs, the accumulation of lithium metal on the negative electrode reduces the battery's charging capacity, and the heat generated internally can damage the battery.

[0004] Therefore, there is a need for the development of technology for methods to effectively detect and suppress lithium electrodeposition in lithium batteries. The problem to be solved

[0005] Accordingly, the technical problem of the present invention is conceived from this point, and the objective of the present invention is to provide a method for detecting and suppressing lithium electrodeposition in a lithium battery, which measures the terminal voltage while charging the lithium battery with a charging current, divides the terminal voltage into multiple voltage ranges, and measures the charging characteristics for each voltage range to detect lithium electrodeposition, in order to overcome the limitations of the prior art described above.

[0006] In addition, another objective of the present invention is to provide a method for detecting and suppressing lithium electrodeposition in a lithium battery, wherein lithium electrodeposition is determined when the charging characteristics of the current charging cycle increase continuously over a single voltage range or multiple voltage ranges compared to the charging characteristics of the previous charging cycle.

[0007] In addition, another objective of the present invention is to provide a method for detecting and suppressing lithium electrodeposition in a lithium battery, wherein a vector distance consisting of charging characteristics of a single or continuous voltage interval between a current charging cycle and a previous charging cycle is determined to be lithium electrodeposition if it exceeds a threshold value.

[0008] In addition, another objective of the present invention is to provide a method for detecting and suppressing lithium electrodeposition in a lithium battery, which reduces the charging current of the lithium battery after the lithium electrodeposition onset to mitigate or prevent lithium electrodeposition.

[0009] In addition, another objective of the present invention is to provide a method for detecting and suppressing lithium electrodeposition in a lithium battery, wherein the lithium battery is discharged after the lithium electrodeposition onset to mitigate or prevent lithium electrodeposition.

[0010] The technical problems of the present disclosure are not limited to those mentioned above, and other technical problems not mentioned above will be clearly understood by a person skilled in the art of the present disclosure from the description below. means of solving the problem

[0011] A method for detecting and suppressing lithium electrodeposition according to one embodiment of the present disclosure for solving the above technical problem may include: a terminal voltage measurement step of measuring the terminal voltage of the battery while charging the battery with a constant current; a charging characteristic measurement step of dividing the terminal voltage into a plurality of voltage intervals and measuring a charging characteristic corresponding to the charging time for each voltage interval; a charging characteristic comparison step of comparing the charging characteristics of the same voltage interval of a first charging cycle and a second charging cycle; and an electrodeposition determination step of determining lithium electrodeposition if the charging characteristic of the first charging cycle differs from the charging characteristic of the second charging cycle in a single or plurality of voltage intervals.

[0012] In one embodiment, the constant current may be a single-step constant current or a multi-step constant current.

[0013] In one embodiment, the charging characteristic is a charging time, and the charging time may be the time required for the terminal voltage to increase in each voltage range.

[0014] In one embodiment, the charging characteristic is a charging capacity, and the charging capacity may be the integrated value of the charging current required to increase the terminal voltage in each voltage range.

[0015] In one embodiment, the first charging cycle may be the current charging cycle, and the second charging cycle may be the previous charging cycle.

[0016] In one embodiment, the electrodeposition determination step may include a step of determining lithium electrodeposition if, in the single or plurality of voltage intervals, the charging characteristic of the first charging cycle increases more than the charging characteristic of the second charging cycle, or if the vector distance consisting of the charging characteristics of the single or continuous voltage intervals of the first charging cycle and the second charging cycle exceeds a threshold value.

[0017] In one embodiment, a lithium electrodeposition inhibition step may be included to reduce the charging current after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance.

[0018] In one embodiment, a lithium electrodeposition inhibition step may be included for discharging the lithium battery after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance.

[0019] In one embodiment, the discharge of the lithium battery may be in the form of a constant current or a current pulse.

[0020] In one embodiment, when discharged in the form of current pulses, the number of current pulses, the amplitude of the current pulses, or the duty cycle of the current pulses can be controlled based on the vector distance.

[0021] In one embodiment, when discharged in the form of a current pulse, the frequency of the current pulse may be a frequency at which the impedance of the lithium battery is minimized.

[0022] In one embodiment, when discharged in the form of a current pulse, the frequency of the current pulse may be a frequency at which the phase of the impedance of the lithium battery becomes zero.

[0023] A computing device implementing a method for detecting and suppressing lithium electrodeposition according to one embodiment of the present disclosure, wherein the computing device measures the terminal voltage of the battery while charging the battery with a constant current, divides the terminal voltage into a plurality of voltage intervals, and measures a charging characteristic corresponding to the charging time for each voltage interval to implement a method for detecting and suppressing lithium electrodeposition of the battery, comprising: one or more processors; a communication interface communicating with an external device; a memory for loading a computer program performed by the processor and a storage device for storing the computer program, wherein the computer program may include instructions for performing: an operation of comparing the charging characteristics of the same voltage interval of a first charging cycle and a second charging cycle; and an operation of determining lithium electrodeposition if the charging characteristics of the first charging cycle differ from the charging characteristics of the second charging cycle in a plurality of voltage intervals.

[0024] In one embodiment, the operation of determining lithium electrodeposition may include determining lithium electrodeposition if, in the single or plurality of voltage intervals, the charging characteristic of the first charging cycle increases more than the charging characteristic of the second charging cycle, or if the vector distance consisting of the charging characteristics of the single or continuous voltage intervals of the first charging cycle and the second charging cycle exceeds a threshold value.

[0025] In one embodiment, the computer program may include instructions for performing an operation to reduce the charging current after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance, or an operation to discharge the lithium battery after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance. Effects of the invention

[0026] As described above, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein the terminal voltage is measured while charging the lithium battery with a charging current, the terminal voltage is divided into a plurality of voltage sections, and charging characteristics are measured for each voltage section to detect lithium electrodeposition.

[0027] In addition, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein if the charging characteristics of the current charging cycle increase in multiple voltage intervals consecutively compared to the charging characteristics of the previous charging cycle, it is determined to be lithium electrodeposition.

[0028] In addition, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein if the vector distance, which is composed of charging characteristics of a single or continuous voltage interval of the current charging cycle and the previous charging cycle, exceeds a threshold value, it is determined to be lithium electrodeposition.

[0029] In addition, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, which reduces the charging current of the lithium battery after the lithium electrodeposition onset to mitigate or prevent lithium electrodeposition.

[0030] In addition, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, which discharges the lithium battery after the lithium electrodeposition onset to alleviate or prevent lithium electrodeposition.

[0031] In addition, various effects that can be identified directly or indirectly through this specification may be provided. Brief explanation of the drawing

[0032] FIG. 1 is a drawing for explaining a method for detecting and suppressing lithium electrodeposition in a lithium battery according to one embodiment of the present disclosure. Figure 2 is a flowchart for explaining the lithium electrodeposition detection step of Figure 1. Figure 3 is a flowchart for explaining the charging characteristic measurement step of Figure 2. Figure 4 is a graph showing the terminal voltage and charging characteristics measured in the terminal voltage measurement step and charging characteristic measurement step of Figure 2. Figure 5 is a flowchart for explaining the lithium electrodeposition determination step of Figure 2. Figure 6 is a flowchart for explaining the lithium electrodeposition inhibition step of Figure 2. Figure 7 is a graph to explain the charging current reduction step of the lithium electrodeposition inhibition step of Figure 2. FIG. 8 is a flowchart for explaining the charging current discharge step of the lithium electrodeposition inhibition step of FIG. 2. Figure 9 is a graph illustrating the constant current discharge of Figure 8. Figure 10 is a graph illustrating the pulse current discharge of Figure 8. Figure 11 is another graph illustrating the pulse current discharge of Figure 8. FIG. 12 is an example block diagram of a computing device capable of implementing a method for detecting and suppressing lithium electrodeposition of a lithium battery according to one embodiment of the present disclosure. Specific details for implementing the invention

[0033] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the attached drawings. However, the technical concept of the present disclosure is not limited to the following embodiments but can be implemented in various different forms. The following embodiments are provided merely to complete the technical concept of the present disclosure and to fully inform those skilled in the art of the scope of the present disclosure, and the technical concept of the present disclosure is defined only by the scope of the claims.

[0034] It should be noted that when assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known components or functions could obscure the essence of the present disclosure, such detailed description is omitted.

[0035] Unless otherwise defined, all terms used herein (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which this disclosure pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise. The terms used herein are for describing the embodiments and are not intended to limit this disclosure. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text.

[0036] Additionally, terms such as first, second, A, B, (a), (b), etc., may be used to describe the components of the present disclosure. These terms are intended only to distinguish the components from other components and do not limit the nature, order, or sequence of the components. Where it is stated that a component is "connected," "combined," or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but that another component may also be "connected," "combined," or "joined" between each component.

[0037] As used in the specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0038] Hereinafter, several embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0039] FIG. 1 is a drawing for explaining a method for detecting and suppressing lithium electrodeposition in a lithium battery according to one embodiment of the present disclosure.

[0040] Referring to FIG. 1, a method for detecting and suppressing lithium electrodeposition in a lithium battery according to one embodiment of the present disclosure may be configured to include a lithium electrodeposition detection step (S100) and a lithium electrodeposition suppression step (S200).

[0041] The above lithium electrodeposition detection step (S100) may be a step of detecting lithium electrodeposition by measuring the terminal voltage of the lithium battery while charging the lithium battery with a charging current, dividing the terminal voltage into multiple voltage intervals and measuring the charging characteristics for each voltage interval, and then comparing the charging characteristics of the same voltage interval of the current charging cycle with those of the previous charging cycle; if the charging characteristics of the current charging cycle increase compared to the charging characteristics of the previous charging cycle in a single voltage interval, or increase compared to the charging characteristics of the previous charging cycle in multiple consecutive voltage intervals, it is determined to be lithium electrodeposition. Here, the charging characteristics may be charging time or charging capacity.

[0042] The above lithium electrodeposition suppression step (S200) can reduce the charging current after the lithium electrodeposition onset determined in the lithium electrodeposition detection step based on the vector distance, or discharge the lithium battery after the lithium electrodeposition onset. Here, the vector distance may be composed of the charging characteristics of a single voltage interval or a continuous voltage interval of the current charging cycle and the previous charging cycle.

[0043] According to the method for detecting and suppressing lithium electrodeposition in a lithium battery according to one embodiment of the present disclosure, since lithium electrodeposition appears as a phenomenon in which charging characteristics increase over time, lithium electrodeposition can be detected by comparing the charging characteristics of the current charging cycle with those of the previous charging cycle.

[0044] In addition, according to one embodiment of the present disclosure, lithium electrodeposition can be detected early in the lithium electrodeposition detection step (S100) to reduce or mitigate lithium electrodeposition by reducing the charging current of the lithium battery or discharging the lithium battery, thereby reducing the performance degradation, shortened lifespan, and risk of explosion of the lithium battery caused by lithium electrodeposition.

[0045] Figure 2 is a flowchart for explaining the lithium electrodeposition detection step of Figure 1.

[0046] Referring to FIG. 2, the lithium electrodeposition detection step (S100) may be configured to include a terminal voltage measurement step (S110), a charging characteristic measurement step (S120), and a lithium electrodeposition determination step (S130).

[0047] The terminal voltage measurement step (S110) and the charging characteristic measurement step (S120) may be performed in multiple charging cycles. For example, the terminal voltage measurement step (S110) and the charging characteristic measurement step (S120) may be performed in k charging cycles (k is a natural number).

[0048] The above terminal voltage measurement step (S110) may be a step of measuring the cell terminal voltage of a lithium battery while charging the lithium battery with a charging current.

[0049] As an example, the charging current may be a single-step constant current. A single-step constant current can be used for simple and fast charging in a manner where a constant current of a constant magnitude is supplied during the charging process.

[0050] As an example, the charging current can be a multi-step constant current. A multi-step constant current is a method in which a constant current of various magnitudes is supplied during the charging process, and it can be selected and used when there is a desire to precisely manage the performance and lifespan of a lithium battery. When charging with a multi-step constant current, the lithium battery can be charged by starting with a large current at the beginning of charging and gradually reducing the magnitude of the current.

[0051] The charging characteristic measurement step (S120) above may be a step of dividing the terminal voltage into a plurality of voltage intervals and measuring the charging characteristic for each voltage interval. The charging characteristic measurement step (S120) may divide the terminal voltage into a plurality of voltage intervals, measure the charging characteristic for each voltage interval, and store it in a lookup table. Each voltage interval may have the same size but is not limited thereto, and each voltage interval may have different sizes.

[0052] As an example, the charging characteristic may be the charging time. For example, in the charging characteristic measurement step (S120), the terminal voltage may be divided into multiple voltage sections, and the charging time required for charging in each voltage section may be measured. The charging time may be the time required for the terminal voltage to increase to a certain voltage in each voltage section, and may represent the charging speed for each voltage section in which charging proceeds in each voltage section.

[0053] As an example, the charging characteristic may be the charging capacity. For example, in the charging characteristic measurement step (S120), the terminal voltage may be divided into a plurality of voltage ranges, and the charging capacity may be measured for each voltage range. The charging capacity is such that the terminal voltage in each voltage range is a constant voltage. It may be the integrated value of the charging current required to increase. Therefore, the charging capacity can be expressed by the following mathematical formula 1.

[0054]

[0055] Here, k represents the k-th measurement cycle, and n represents the n-th voltage interval.

[0056] In this embodiment, lithium electrodeposition may appear as a phenomenon where charging characteristics increase. By dividing the terminal voltage into multiple voltage ranges, charging characteristics can be measured more precisely, allowing for early detection of lithium electrodeposition. Additionally, changes in terminal voltage can be measured more precisely, enabling more accurate measurement of charging characteristics.

[0057] The above lithium electrodeposition determination step (S130) may be a step of determining lithium electrodeposition by comparing the charging characteristics of the same voltage range of the current charging cycle and the previous charging cycle.

[0058] As an example, in the lithium electrodeposition determination step (S130), if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in any single voltage interval, or increases compared to the charging time of the previous charging cycle in multiple consecutive voltage intervals, it can be determined that the lithium battery is lithium electrodeposited. For example, if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in one voltage interval, it can be determined that the lithium battery is lithium electrodeposited. In addition, if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in three consecutive voltage intervals, it can be determined that the lithium battery is lithium electrodeposited.

[0059] As an example, the lithium electrodeposition determination step (S130) may determine that lithium is electrodeposited in the lithium battery when the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in a single voltage interval or in a plurality of consecutive voltage intervals, and the vector distance exceeds a threshold. Here, the vector distance may be composed of the charging times of consecutive voltage intervals of the current charging cycle and the previous charging cycle.

[0060] As an example, the lithium electrodeposition determination step (S130) can determine that the lithium battery is lithium electrodeposited if the charge capacity of the current charge cycle increases compared to the charge capacity of the previous charge cycle in any single voltage interval, or increases compared to the charge capacity of the previous charge cycle in multiple consecutive voltage intervals. For example, if the charge capacity of the current charge cycle increases compared to the charge capacity of the previous charge cycle in one voltage interval, the lithium battery is determined to be lithium electrodeposited. Additionally, if the charge capacity of the current charge cycle increases compared to the charge capacity of the previous charge cycle in three consecutive voltage intervals, the lithium battery is determined to be lithium electrodeposited.

[0061] As an example, the lithium electrodeposition determination step (S130) may determine that lithium is electrodeposited in the lithium battery when the charging capacity of the current charging cycle increases compared to the charging capacity of the previous charging cycle in a single voltage range or in a plurality of consecutive voltage ranges, and the vector distance exceeds a threshold. Here, the vector distance may be composed of the charging capacities of consecutive voltage ranges of the current charging cycle and the previous charging cycle.

[0062] The previous charge cycle may be the cycle immediately preceding the current charge cycle, but is not limited thereto; the previous charge cycle may also be a charge cycle prior to the current charge cycle that is not immediately preceding it. The number of consecutive voltage intervals can be determined as the optimal number through experimentation.

[0063] Figure 3 is a flowchart for explaining the charging characteristic measurement step of Figure 2.

[0064] Referring to FIG. 3, the charging characteristic measurement step (S120) of FIG. 2 can proceed to different measurement steps when the charging characteristic is charging time and when it is charging capacity. The charging characteristic measurement step (S120) can proceed to k charging cycles (k is a natural number).

[0065] First, the charging characteristic measurement step (S120) is described when the charging characteristic is charging time. When the charging characteristic is charging time, the charging characteristic measurement step (S120) may include a charging time measurement step (S121) and a charging time comparison step (S123).

[0066] In the charging time measurement step (S121) above, the terminal voltage is divided into a plurality of voltage intervals, and the charging time can be measured for each voltage interval, and the charging time measured for each voltage interval can be stored in a lookup table. The charging time is for each voltage interval (V n - V n-1 It can be the time required for the terminal voltage to increase by △V, and can be defined as the charging time vector △t. Here, n can be the number of measured terminal voltages.

[0067] For example, based on the 7 terminal voltages (V1, V2, V3, V4, V5, V6, V7) measured in the charging time measurement step (S121), the terminal voltage is divided into 6 terminal voltage intervals (△V k,1 , △V k,2 , △V k,3 , △V k,4 , △V k,5 , △V k,6 , △V k,7 It can be divided into ). And, based on the 7 measurement times (t1, t2, t3, t4, t5, t6, t7) corresponding to the 7 measured terminal voltages, the charging time is 6 charging times (△t k,1 , △t k,2 , △t k,3 , △t k,4 , △t k,5 , △t k,6 It can be divided into ).

[0068] Each of the 6 charging times is (△t k,1 = t2- t1), (△t k,2 = t3- t2), (△t k,3 = t4- t3), (△t k,4 = t5- t4), (△t k,5= t6- t5), (△t k,6 It can be expressed as = t7- t6), and each of these is the charging time vector △t k It can be defined as. Fig. 4 is a graph of terminal voltage and charging time measured in the terminal voltage measurement step and the charging characteristic measurement step, where the x-axis of the terminal voltage and charging characteristic graph represents the measurement time and the y-axis represents the terminal voltage. Fig. 4 shows the 7 terminal voltages (V1, V2, V3, V4, V5, V6, V7) and 6 terminal voltage intervals (△V) described above. k,1 , △V k,2 , △V k,3 , △V k,4 , △V k,5 , △V k,6 , △V k,7 ), 7 measurement times (t1, t2, t3, t4, t5, t6, t7) and 6 charging times (△t k,1 , △t k,2 , △t k,3 , △t k,4 , △t k,5 , △t k,6 Displays ) as a graph.

[0069] As an example, when the charging time measurement step (S121) is performed k (k is a natural number) charging cycles, the charging time vector measured in the current charging cycle (k) is [△t k,1 , △t k,2, △t k,3, △t k,4, △t k,5, △t k,6 ] may be, and the charging time vector measured in the previous charging cycle (k-1) is [△t k-1,1 , △t k-1,2, △t k-1,3, △t k-1,4, △t k-1,5, △t k-1,6 ] can be.

[0070] In the above charging time comparison step (S123), the charging time of the same voltage interval of the current charging cycle and the previous charging cycle can be compared.

[0071] Next, the charging characteristic measurement step (S120) is described when the charging characteristic is charging capacity. When the charging characteristic is charging capacity, the charging characteristic measurement step (S120) may include a charging capacity measurement step (S122) and a charging capacity comparison step (S124).

[0072] In the charging time measurement step (S122) above, the terminal voltage is divided into a plurality of voltage intervals, and the charging capacity can be measured for each voltage interval, and the charging capacity measured for each voltage interval can be stored in a lookup table. The charging capacity is for each voltage interval (V n - V n-1 The charging current required to increase the terminal voltage by △V in ) can be an integrated value and can be defined as the charging capacitance vector △Q. Here, n can be the number of measured terminal voltages.

[0073] For example, based on the 7 terminal voltages (V1, V2, V3, V4, V5, V6, V7) measured in the charging capacity measurement step (S122), the terminal voltage is divided into 6 terminal voltage intervals (△V k,1 , △V k,2 , △V k,3 , △V k,4 , △V k,5 , △V k,6 , △V k,7 It can be divided into ). And, based on the 7 measured capacitances (Q1, Q2, Q3, Q4, Q5, Q6, Q7) corresponding to the 7 measured terminal voltages, the charging capacitance is 6 charging capacitances (△Q k,1 , △Q k,2 , △Q k,3 , △Q k,4 , △Q k,5 , △Q k,6 It can be divided into ).

[0074] Each of the 6 charging capacities is (△Q k,1 = Q2- Q1), (△Q k,2 = Q3- Q2), (△Q k,3 = Q4- Q3), (△Q k,4= Q5- Q4), (△Q k,5 = Q6- Q5), (△Q k,6 It can be expressed as = Q7- Q6), and each of these is the capacitance vector △Q k It can be defined as.

[0075] As an example, when the charging capacity measurement step (S122) is performed k (k is a natural number) charging cycles, the charging capacity vector measured in the current charging cycle (k) is [△Q k,1 , △Q k,2, △Q k,3, △Q k,4, △Q k,5, △Q k,6 ] can be, and the charge capacity vector measured in the previous charge cycle (k-1) is [△Q k-1,1 , △Q k-1,2, △Q k-1,3, △Q k-1,4, △Q k-1,5, △Q k-1,6 ] can be.

[0076] In the above charging capacity comparison step (S124), the charging capacity of the same voltage range of the current charging cycle and the previous charging cycle can be compared.

[0077] Figure 5 is a flowchart for explaining the lithium electrodeposition determination step (charging time) of Figure 2.

[0078] Referring to FIG. 5, the lithium electrodeposition determination step (S130) may be configured to include a determination step (S131) ​​based on an increase in charging time and a determination step (S133) based on exceeding a vector distance threshold.

[0079] The determination step (S131) ​​based on the increase in charging time above can determine that lithium is deposited in the lithium battery if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in a single voltage interval or in a plurality of consecutive voltage intervals.

[0080] As an example, if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle in one voltage interval, it can be determined that the lithium battery is lithium electrodeposited.

[0081] For example, the charging time vector [△t measured in the current charging cycle (k) k,1 , △t k,2, △t k,3, △t k,4, △t k,5, △t k,6 Charging time vector corresponding to one of the voltage intervals in ] △t k,5 is selected, and the charging time vector [△t measured in the previous charging cycle (k-1) k-1,1 , △t k-1,2, △t k-1,3, △t k-1,4, △t k-1,5, △t k-1,6 ] Among them, the charging time vector △t of the same voltage interval as the charging time vector selected in the current charging cycle k-1,5 You can select and compare them with each other.

[0082] The charging time vector △t of the selected current charging cycle k,5 and the previous charging cycle charging time vector △t k-1,5 By comparing, if the charging time vector of the current charging cycle increases compared to the charging time vector of the previous charging cycle, it can be determined that lithium of the lithium battery is being electrodeposited.

[0083] To explain again, in the determination step (S131) ​​due to the increase in charging time, the charging time vector △t of the current charging cycle k,5 △t, the charging time vector of the previous charging cycle k-1,5 If it is greater than (△t k,5 > △t k-1,5 ), it can be determined that lithium of the lithium battery is electrodeposited.

[0084] For example, if the charging time of the current charging cycle increases compared to the charging time of the previous charging cycle for three consecutive voltage intervals, it can be determined that the lithium battery is lithium-electroplated.

[0085] For example, the charging time vector [△t measured in the current charging cycle (k) k,1 , △t k,2, △t k,3, △t k,4, △t k,5, △t k,6 The charging time vector △t corresponding to three consecutive voltage intervals among ] k,4, △t k,5, △t k,6 is selected, and the charging time vector [△t measured in the previous charging cycle (k-1) k-1,1 , △t k-1,2, △t k-1,3, △t k-1,4, △t k-1,5, △t k-1,6 ] Among them, the charging time vector △t of the same voltage interval as the charging time vector selected in the current charging cycle k-1,4, △t k-1,5, △t k-1,6 You can select and compare each one.

[0086] The charging time vector △t of the selected current charging cycle k,4, △t k,5, △t k,6 and the previous charging cycle charging time vector △t k-1,4, △t k-1,5, △t k-1,6 By comparing with the same terminal voltage interval, if the charging time vector of the current charging cycle continuously increases compared to the charging time vector of the previous charging cycle, it can be determined that lithium of the lithium battery is being electrodeposited.

[0087] To explain again, in the determination step (S131) ​​due to the increase in charging time, the charging time vector △t of the current charging cycle k,4 △t, the charging time vector of the previous charging cycle k-1,4 Greater than (△t k,4 > △t k-1,4), charging time vector △t of the current charging cycle k,5 △t, the charging time vector of the previous charging cycle k-1,5 Greater than (△t k,5 > △t k-1,5 ), charging time vector △t of the current charging cycle k,6 △t, the charging time vector of the previous charging cycle k-1,6 If it is greater than (△t k,6 > △t k-1,6 ), it can be determined that lithium of the lithium battery is electrodeposited.

[0088] The determination step (S133) based on exceeding the above vector distance threshold value may be a step of determining lithium electrodeposition if the vector distance, which consists of the charging time of a single voltage interval or a continuous voltage interval of the current charging cycle and the previous charging cycle, exceeds the threshold value.

[0089] As an example, if the vector distance consisting of three consecutive voltage intervals between the current charging cycle and the previous charging cycle exceeds a threshold value, it can be determined that lithium is being deposited in the lithium battery. For example, the vector distance d, consisting of three consecutive voltage intervals, can be calculated using the following mathematical formula.

[0090]

[0091] Here, k represents the k-th measurement cycle; that is, the k-th cycle refers to the current charge interval, and the k-1th cycle may refer to the previous charge cycle.

[0092] Figure 6 is a flowchart for explaining the lithium electrodeposition determination step (charge capacity) of Figure 2.

[0093] Referring to FIG. 6, the lithium electrodeposition determination step (S130) may be configured to include a determination step based on an increase in charge capacity (S132) and a determination step based on exceeding a vector distance threshold (S134).

[0094] The determination step (S132) based on the increase in charging capacity above can determine that the lithium battery is lithium-electrodeposited if the charging capacity of the current charging cycle increases compared to the charging capacity of the previous charging cycle in a single voltage range or in a plurality of consecutive voltage ranges.

[0095] As an example, if the charge capacity of the current charge cycle increases compared to the charge capacity of the previous charge cycle in one voltage range, it can be determined that the lithium battery is lithium electrodeposited.

[0096] For example, the charge capacity vector [△Q measured in the current charge cycle (k) k,1 , △Q k,2, △Q k,3, △Q k,4, △Q k,5, △Q k,6 The charging capacitance vector △Q corresponding to one of the voltage intervals in ] k,6 This is selected, and the charge capacity vector [△Q] measured in the previous charge cycle (k-1) k-1,1 , △Q k-1,2, △Q k-1,3, △Q k-1,4, △tQ -1,5, △Q k-1,6 ] Among them, the charging capacity vector △t in the same voltage range as the charging capacity vector selected in the current charging cycle k-1,6 You can select and compare them with each other.

[0097] The charge capacity vector △Q of the selected current charge cycle k,6 and the previous charging cycle charge capacity vector △Q k-1,6 By comparing, if the charge capacity vector of the current charge cycle increases compared to the charge capacity vector of the previous charge cycle, it can be determined that lithium of the lithium battery is being electrodeposited.

[0098] To explain again, in the determination step (S132) based on the increase in charging capacity, the charging capacity vector △Q of the current charging cycle k,6 ΔQ is the charge capacity vector of the previous charge cycle k-1,6 If it is greater than (△Q k,6 △Q k-1,6), it can be determined that lithium of the lithium battery is electrodeposited.

[0099] As an example, if the charge capacity of the current charge cycle increases compared to the charge capacity of the previous charge cycle for three consecutive voltage intervals, it can be determined that the lithium battery is lithium-electroplated.

[0100] For example, the charge capacity vector [△Q measured in the current charge cycle (k) k,1 , △Q k,2, △Q k,3, △Q k,4, △Q k,5, △Q k,6 The charge capacitance vector △Q corresponding to three consecutive voltage intervals among ] k,4, △Q k,5, △Q k,6 is selected, and the charge capacity vector [△Q measured in the previous charge cycle (k-1) is selected. k-1,1 , △Q k-1,2, △Q k-1,3, △Q k-1,4, △tQ -1,5, △Q k-1,6 ] Among them, the charging capacity vector △t in the same voltage range as the charging capacity vector selected in the current charging cycle k-1,4, △t k-1,5, △t k-1,6 You can select and compare each one.

[0101] The charge capacity vector △Q of the selected current charge cycle k,4, △Q k,5, △Q k,6 and the previous charging cycle charge capacity vector △Q k-1,4, △Q k-1,5, △Q k-1,6 By comparing with the same terminal voltage range, if the charge capacity vector of the current charge cycle continuously increases compared to the charge capacity vector of the previous charge cycle, it can be determined that lithium of the lithium battery is being electrodeposited.

[0102] To explain again, in the determination step (S132) based on the increase in charging capacity, the charging capacity vector △Q of the current charging cycle k,4 ΔQ is the charge capacity vector of the previous charge cyclek-1,4 Greater than (△Q k,4 △Q k-1,4 ), charging capacity vector △Q of the current charging cycle k,5 ΔQ is the charge capacity vector of the previous charge cycle k-1,5 Greater than (△Q k,5 △Q k-1,5 ), charging capacity vector △Q of the current charging cycle k,6 ΔQ is the charge capacity vector of the previous charge cycle k-1,6 If it is greater than (△Q k,6 △Q k-1,6 ), it can be determined that lithium of the lithium battery is electrodeposited.

[0103] The determination step (S136) based on exceeding the vector distance threshold value may be a step of determining lithium electrodeposition if the vector distance, which consists of the charging capacity of consecutive voltage intervals of the current charging cycle and the previous charging cycle, exceeds the threshold value.

[0104] As an example, if the vector distance consisting of three consecutive voltage intervals between the current charging cycle and the previous charging cycle exceeds a threshold value, it can be determined that lithium is being deposited in the lithium battery. For example, the vector distance d, consisting of three consecutive voltage intervals, can be calculated using the following mathematical formula.

[0105]

[0106] Here, k represents the k-th measurement cycle; that is, the k-th cycle refers to the current charge interval, and the k-1th cycle may refer to the previous charge cycle.

[0107] Figure 7 is a flowchart for explaining the lithium electrodeposition inhibition step of Figure 2.

[0108] Referring to FIG. 7, the lithium electrodeposition suppression step (S200) may be configured to include a charging current reduction step (S210) and a charging current discharge step (S220).

[0109] The above charging current reduction step (S210) may be a step of reducing the charging current supplied to the lithium battery after lithium electrodeposition has started. Reducing the charging current that charges the lithium battery slows down the movement speed of lithium ions, thereby mitigating or preventing lithium electrodeposition.

[0110] For example, referring to FIG. 8, the charging current reduction step (S210) can reduce the charging current after the lithium electrodeposition start point (onset of lithium planting) determined in the electrodeposition determination step (S130) based on the vector distance. The vector distance can be obtained by comparing the charging characteristics (charging time or charging capacity) of the current charging cycle and the previous charging cycle. For example, the charging current reduction step (S210) can reduce the charging current immediately after lithium electrodeposition begins. Alternatively, it may be observed for a certain period of time after lithium electrodeposition begins, and if the charging characteristics continue to increase, the charging current may be reduced.

[0111] The charging current discharge step (S220) described above may be a step of discharging the lithium battery after lithium electrodeposition has started based on vector distance. When the lithium battery is discharged, lithium ions move from the positive electrode to the negative electrode, and lithium ions on the surface of the negative electrode where lithium electrodeposition occurred can dissolve and move to the positive electrode. As an example, the charging current discharge step (S220) may discharge the lithium battery after the lithium electrodeposition start point (onset of lithium planting) determined in the electrodeposition determination step based on vector distance.

[0112] FIG. 9 is a flowchart for explaining the charging current discharge step of the lithium electrodeposition inhibition step of FIG. 2.

[0113] Referring to FIG. 9, the charging current discharge step (S220) may include a constant current discharge step (S221) and a pulse current discharge step (S222).

[0114] The above constant current discharge step (S221) is a step of discharging a lithium battery in the form of a constant current, and as shown in FIG. 10, it may be a method of discharging the lithium battery with a constant current after the lithium electrodeposition starting point (onset of Lithium planting) determined in the electrodeposition determination step (S130) based on vector distance.

[0115] The above pulse current discharge step (S222) is a step of discharging a lithium battery in a manner that discharges current for a certain period of time and does not discharge current for a certain period of time, and may be a method of repeatedly discharging the lithium battery after the lithium electrodeposition starting point (onset of Lithium planting) determined in the electrodeposition determination step (S130) based on vector distance as shown in FIG. 11.

[0116] For example, when discharged in the form of current pulses, the number of current pulses, the amplitude of the current pulses, or the duty cycle of the current pulses can be controlled based on vector distance. When discharged in the form of current pulses, the amount of discharge current can be finely controlled through the control of the number of current pulses, the amplitude of the current pulses, or the duty cycle of the current pulses.

[0117] As an example, as illustrated in FIG. 12, when discharged in the form of a current pulse, the frequency of the current pulse may be a frequency at which the impedance (z) of the lithium battery is minimized. For example, the impedance of the lithium battery may decrease as the frequency of the current pulse increases. In other words, the impedance of the lithium battery may vary depending on the frequency of the current pulse, and if discharged as a current pulse at a frequency at which the impedance of the lithium battery is minimized, the resistance to movement of lithium ions is reduced, and lithium ions dissolve on the negative electrode surface where lithium electrodeposition occurred, which may be effective in alleviating lithium electrodeposition.

[0118] As an example, when discharged in the form of a current pulse, the frequency of the current pulse may be a frequency at which the phase (θ) of the impedance of the lithium battery becomes zero. A current pulse discharge at a frequency at which the phase (θ) of the impedance of the lithium battery becomes zero can move lithium ions from the negative electrode to the positive electrode, thereby suppressing or mitigating lithium electrodeposition on the surface of the negative electrode where lithium electrodeposition had occurred.

[0119] FIG. 13 is an example block diagram of a computing device capable of implementing a method for detecting and suppressing lithium electrodeposition in a lithium battery according to one embodiment of the present disclosure.

[0120] Referring to FIG. 13, an exemplary computing device (300) capable of implementing a method for detecting and suppressing lithium electrodeposition of a lithium battery according to one embodiment of the present disclosure may include a processor (310), a system bus (360), a communication interface (320), a memory (340), and a storage (330).

[0121] The above processor (310) can control the overall operation of the lithium electrodeposition detection and suppression method of a lithium battery. For example, the processor (310) may be a component that controls the lithium electrodeposition detection operation, which detects lithium electrodeposition by determining lithium electrodeposition if the charging characteristics of the current charging cycle and the previous charging cycle increase in a single voltage range or in a series of multiple voltage ranges, after measuring the terminal voltage of the lithium battery while charging the lithium battery with a charging current and dividing the terminal voltage into multiple voltage ranges to measure the charging characteristics for each voltage range, and then comparing the charging characteristics of the same voltage range of the current charging cycle with those of the previous charging cycle, and determining lithium electrodeposition in a single voltage range or in a series of multiple voltage ranges, and the lithium electrodeposition suppression operation, which reduces the charging current after the lithium electrodeposition onset determined in the lithium electrodeposition detection step based on vector distance or discharges the lithium battery after the lithium electrodeposition onset.

[0122] The memory (340) may store various data, commands, and information for executing a computer program (350), and may load one or more computer programs (350) from storage (330) to execute an operation according to an embodiment of the present disclosure. The bus (360) may provide a communication function between components of the computing device (300). The communication interface (320) may include a communication module that supports wired and wireless internet communication and various communication methods of the computing device (300). The storage (330) may store one or more computer programs (350) non-temporarily.

[0123] The above computer program (350) may include one or more instructions that implement operations according to an embodiment of the present disclosure. When the computer program (350) is loaded into memory (340), the processor (310) may perform operations according to an embodiment of the present disclosure by executing one or more instructions.

[0124] In one embodiment, the computer program (350) may be a computer program that implements operation control of a method for detecting and suppressing lithium electrodeposition of a lithium battery. For example, the computer program (350) may include instructions for performing operations such as: comparing the charging characteristics of the same voltage range of the current charging cycle and the previous charging cycle; and determining lithium electrodeposition if the charging characteristics of the current charging cycle increase continuously over a plurality of voltage ranges compared to the charging characteristics of the previous charging cycle; and instructions for performing operations such as reducing the charging current after the lithium electrodeposition onset determined in the electrodeposition determination step based on vector distance, or discharging the lithium battery after the lithium electrodeposition onset determined in the electrodeposition determination step based on vector distance.

[0125] Here, the operation of determining lithium electrodeposition may include determining lithium electrodeposition if the vector distance composed of the charging characteristics of a single or continuous voltage interval of the first charging cycle and the second charging cycle exceeds a threshold value.

[0126] As described above, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein the terminal voltage is measured while charging the lithium battery with a charging current, the terminal voltage is divided into multiple voltage intervals, and charging characteristics are measured for each voltage interval to detect lithium electrodeposition. Furthermore, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein lithium electrodeposition is determined if the charging characteristics of the current charging cycle increase continuously in multiple voltage intervals compared to the charging characteristics of the previous charging cycle. Furthermore, according to the present embodiment, a method for detecting and suppressing lithium electrodeposition in a lithium battery can be provided, wherein lithium electrodeposition is determined if the vector distance consisting of the charging characteristics of a single or consecutive voltage interval between the current charging cycle and the previous charging cycle exceeds a threshold value.

[0127] Various embodiments of the present disclosure and effects according to those embodiments have been described with reference to FIGS. 1 to 13. The effects according to the technical concept of the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below.

[0128] Although the operations are depicted in a specific order in the drawings, it should not be understood that the operations must be executed in the specific order depicted or in a sequential order, or that all depicted operations must be executed to obtain the desired result, and in certain situations, multitasking and parallel processing may be advantageous.

[0129] Although embodiments of the present disclosure have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be practiced in other specific forms without altering the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within the equivalent scope shall be interpreted as being included within the scope of rights of the technical concepts defined by the present disclosure.

Claims

Claim 1 A method for detecting and suppressing lithium electrodeposition, comprising: a terminal voltage measurement step of measuring the terminal voltage of the battery while charging the battery with a constant current; a charging characteristic measurement step of dividing the terminal voltage into a plurality of voltage sections and measuring a charging characteristic corresponding to the charging time for each voltage section; a charging characteristic comparison step of comparing the charging characteristics of the same voltage section of a first charging cycle and a second charging cycle; and an electrodeposition determination step of determining lithium electrodeposition if the charging characteristic of the first charging cycle differs from the charging characteristic of the second charging cycle in a single or plurality of voltage sections; wherein the charging characteristic is at least one of charging time and charging capacity, the charging time is the time required for the terminal voltage to increase in each voltage section, and the charging capacity is the integrated value of the charging current required for the terminal voltage to increase in each voltage section. Claim 2 A method for detecting and suppressing lithium electrodeposition according to claim 1, wherein the constant current is a single-step constant current or a multi-step constant current. Claim 3 delete Claim 4 delete Claim 5 A method for detecting and suppressing lithium electrodeposition according to claim 1, wherein the first charging cycle is the current charging cycle and the second charging cycle is the previous charging cycle. Claim 6 A method for detecting and suppressing lithium electrodeposition according to claim 1, wherein the electrodeposition determination step comprises a step of determining lithium electrodeposition if the charging characteristic of the first charging cycle in the single or multiple voltage intervals increases more than the charging characteristic of the second charging cycle, or if the vector distance consisting of the charging characteristics of the single or continuous voltage intervals of the first charging cycle and the second charging cycle exceeds a threshold value. Claim 7 A method for detecting and suppressing lithium electrodeposition according to claim 6, comprising a lithium electrodeposition suppression step of reducing the charging current after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance. Claim 8 A method for detecting and suppressing lithium electrodeposition according to claim 6, comprising a lithium electrodeposition suppression step of discharging a lithium battery after the lithium electrodeposition onset determined in the electrodeposition determination step based on the vector distance. Claim 9 A method for detecting and suppressing lithium electrodeposition according to claim 8, wherein the discharge of the lithium battery is discharged in the form of a constant current or a current pulse. Claim 10 ◈Claim 10 was abandoned upon payment of the registration fee.◈ A method for detecting and suppressing lithium electrodeposition according to claim 9, wherein, when discharged in the form of current pulses, the number of current pulses, the amplitude of the current pulses, or the duty cycle of the current pulses is controlled based on the vector distance. Claim 11 ◈Claim 11 was abandoned upon payment of the registration fee.◈ A method for detecting and suppressing lithium electrodeposition according to Claim 9, wherein, when discharged in the form of a current pulse, the frequency of the current pulse is the frequency at which the impedance of the lithium battery is minimized. Claim 12 ◈Claim 12 was abandoned upon payment of the registration fee.◈ A method for detecting and suppressing lithium electrodeposition according to Claim 10, wherein, when discharged in the form of a current pulse, the frequency of the current pulse is a frequency at which the phase of the impedance of the lithium battery becomes zero. Claim 13 A computing device that implements a method for detecting and suppressing lithium electrodeposition in a battery by measuring the battery terminal voltage while charging the battery with a constant current, dividing the terminal voltage into a plurality of voltage intervals, and measuring a charging characteristic corresponding to the charging time for each voltage interval, wherein the computing device comprises: one or more processors; a communication interface communicating with an external device; a memory for loading a computer program executed by the processor and a storage device for storing the computer program, wherein the computer program includes instructions for performing: an operation of comparing the charging characteristics of the same voltage interval of a first charging cycle and a second charging cycle; and an operation of determining lithium electrodeposition if the charging characteristic of the first charging cycle differs from the charging characteristic of the second charging cycle in a single voltage interval or in a plurality of voltage intervals, wherein the charging characteristic is at least one of a charging time and a charging capacity, wherein the charging time is the time required for the terminal voltage to increase in each voltage interval, and the charging capacity is the integrated value of the charging current required for the terminal voltage to increase in each voltage interval. Claim 14 A computing device according to claim 13, wherein the operation of determining lithium electrodeposition includes determining lithium electrodeposition when the charging characteristic of the first charging cycle in the single or multiple voltage intervals increases more than the charging characteristic of the second charging cycle, or when the vector distance consisting of the charging characteristics of the single or continuous voltage intervals of the first charging cycle and the second charging cycle exceeds a threshold value. Claim 15 A computing device according to claim 13, wherein the computer program comprises instructions for performing operations to reduce the charging current after the lithium electrodeposition onset determined in the electrodeposition determination step based on vector distance, or to discharge the lithium battery after the lithium electrodeposition onset determined in the electrodeposition determination step based on vector distance.

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