Apparatus and method for diagnosing battery

Abstract

An apparatus for diagnosing a battery according to one embodiment of the present disclosure includes: a curve obtaining unit configured to obtain a battery curve representing a correspondence relationship between a voltage and a capacity of the battery; a curve adjustment unit configured to adjust a preset first reference curve and a preset second reference curve to correspond to the battery curve, and generate a first curve according to an adjustment result; and a control unit configured to diagnose a state of the battery based on a first feature value of a first feature point included in the first curve.

Description

Technical Field

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2024-0006174, filed with the Korean Intellectual Property Office on January 15, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to an apparatus and method for diagnosing a battery, and more particularly to an apparatus and method for diagnosing the state of a battery. Background Technology

[0003] In recent years, the demand for portable electronic products such as laptops, cameras, and mobile phones has increased dramatically, and electric vehicles, energy storage batteries, robots, and satellites have also seen significant development. Therefore, high-performance batteries that allow for repeated charging and discharging are being actively researched.

[0004] Commercially available batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion (Li-ion) batteries. Among these, lithium-ion batteries have attracted significant attention because they exhibit virtually no memory effect compared to nickel-based batteries, and also possess very low self-discharge rates and high energy density.

[0005] Extensive research is being conducted on these batteries in terms of high capacity and high density, but improving lifespan and safety is also crucial. To enhance battery safety, technologies for accurately diagnosing the current state of the battery are needed.

[0006] In particular, it is necessary to prevent lithium deposition on the negative electrode surface (lithium plating). If lithium deposits on the negative electrode surface, it causes side reactions with the electrolyte and changes in the battery's kinetic balance, which can lead to battery degradation. Furthermore, since lithium metal may deposit on the negative electrode surface, an internal short circuit may occur in the battery, posing a risk of fire and explosion. Therefore, a technology is needed to detect whether lithium metal has deposited on the negative electrode surface. Summary of the Invention

[0007] Technical issues

[0008] This disclosure is designed to address problems in the related art, and therefore, this disclosure aims to provide an apparatus and method for diagnosing batteries in a non-destructive manner.

[0009] These and other objects and advantages of this disclosure will become apparent from the following detailed description and will become even more fully apparent from exemplary embodiments thereof. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means and combinations thereof shown in the appended claims.

[0010] Technical solution

[0011] An apparatus for diagnosing a battery according to one aspect of the present disclosure may include: a curve acquisition unit configured to acquire a battery curve representing the correspondence between the battery's voltage and capacity; a curve adjustment unit configured to adjust a preset first reference curve and a preset second reference curve to correspond to the battery curve, and to generate a first curve based on the adjustment result; and a control unit configured to diagnose the state of the battery based on a first feature value of a first feature point included in the first curve.

[0012] The control unit can be configured to diagnose the battery's state as either normal or in a state of available lithium loss.

[0013] The control unit can be configured to diagnose the battery state as a state of available lithium loss when the first characteristic value exceeds a preset first standard value.

[0014] The control unit can be configured to diagnose the battery state as normal when the first characteristic value is less than or equal to the first standard value.

[0015] The control unit can be configured to: calculate the available lithium loss rate based on a preset first reference value, a preset second reference value, and a first characteristic value; compare the calculated available lithium loss rate with a preset second standard value; and diagnose the battery status based on the comparison result.

[0016] The control unit can be configured to diagnose the battery state as a state of available lithium loss when the available lithium loss rate exceeds a second standard value.

[0017] The control unit can be configured to diagnose the battery status as normal when the available lithium loss rate is less than or equal to a second standard value.

[0018] The first reference value can be preset to the SOC of the first reference point included in the first reference curve.

[0019] The second reference value can be preset to the SOC of the second reference point included in the first reference curve.

[0020] The first eigenvalue can be the SOC of the first eigenpoint included in the first curve.

[0021] A battery pack according to another aspect of this disclosure may include means for diagnosing the battery according to one aspect of this disclosure.

[0022] A vehicle according to another aspect of this disclosure may include a device for diagnosing a battery according to one aspect of this disclosure.

[0023] A method for diagnosing a battery according to another aspect of this disclosure may include: a curve acquisition step, which acquires a battery curve representing the correspondence between the battery's voltage and capacity; a curve adjustment step, which adjusts a preset first reference curve and a preset second reference curve to correspond to the battery curve, and generates a first curve based on the adjustment result; and a battery diagnosis step, which diagnoses the state of the battery based on a first feature value of a first feature point included in the first curve.

[0024] Beneficial effects

[0025] According to one aspect of this disclosure, since the degradation mode of the battery can be specifically diagnosed, the current state of the battery can be qualitatively diagnosed in a non-destructive manner.

[0026] The effects of this disclosure are not limited to those mentioned above, and those skilled in the art will clearly understand from the description of the claims other effects not mentioned. Attached Figure Description

[0027] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are intended to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

[0028] Figure 1 This is a schematic diagram illustrating an apparatus for diagnosing a battery according to an embodiment of the present disclosure.

[0029] Figure 2 This is a diagram schematically illustrating the adjustment results of a first reference curve and a second reference curve according to an embodiment of the present disclosure.

[0030] Figure 3 This is a graph used as an example to explain each of the first and second reference curves.

[0031] Figure 4 This is an example graph used to explain the battery curves of the target cell.

[0032] Figures 5 to 7 This is a diagram that is referenced to explain an example of a process for generating a comparison curve for comparison with a battery curve according to an embodiment of the present disclosure.

[0033] Figures 8 to 10 This is a diagram that is referenced to explain another example of the process for generating a comparison curve for comparison with a battery curve according to an embodiment of the present disclosure.

[0034] Figure 11 This diagram is used to explain the differences between the first and second batteries.

[0035] Figure 12 This is a diagram illustrating an exemplary configuration of a battery pack including a device for diagnosing a battery according to an embodiment of this disclosure.

[0036] Figure 13 This is a schematic diagram illustrating a vehicle according to another embodiment of the present disclosure.

[0037] Figure 14 This is a schematic diagram illustrating a method for diagnosing a battery according to yet another embodiment of the present disclosure. Detailed Implementation

[0038] It should be understood that the terms used in the specification and appended claims should not be construed as limited to their ordinary or dictionary meanings, but rather should be interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, on the basis of the principle that the inventors are allowed to define terms appropriately for the purpose of best illustration.

[0039] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes and are not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0040] Furthermore, in describing this disclosure, detailed descriptions of relevant known elements or functions are omitted where such descriptions would obscure key subject matter of the disclosure.

[0041] Terms including ordinal numbers such as “first” and “second” can be used to distinguish one element from another among various elements, but are not intended to limit these elements by these terms.

[0042] Throughout this specification, when a part is referred to as "including" or "contains" any element, unless otherwise expressly stated, it means that the part may also include other elements, rather than excluding other elements.

[0043] Furthermore, throughout the specification, when referring to one part as "connected" to another, it is not limited to the case where they are "directly connected," but also includes the case where they are "indirectly connected" with another element inserted between them.

[0044] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram illustrating a device 100 for diagnosing a battery according to an embodiment of the present disclosure.

[0046] refer to Figure 1The device 100 for diagnosing batteries may include a curve acquisition unit 110, a curve adjustment unit 120, and a control unit 130.

[0047] The curve acquisition unit 110 can be configured to acquire a battery curve representing the relationship between the battery's voltage and capacity.

[0048] Here, a battery refers to a single, physically separable cell with negative and positive terminals. For example, a lithium-ion battery or a lithium polymer battery can be considered a battery. Furthermore, batteries can be cylindrical, prismatic, or pouch-type. Additionally, a battery can refer to a battery bank, battery module, or battery pack in which multiple cells are connected in series and / or parallel. Below, for ease of explanation, a battery will be interpreted as referring to a single, independent cell.

[0049] For example, a battery curve is a curve showing the relationship between voltage V and capacity Q as the battery's state of charge (SOC) increases from a preset starting SOC or 0% to a preset ending SOC or 100%. As another example, a battery curve can show the relationship between voltage V and capacity Q as the battery's state of charge increases from a preset starting SOC or 100% to a preset ending SOC or 0%.

[0050] For example, there are no particular restrictions on the C rate during the charging or discharging process used to generate the battery profile. However, preferably, to obtain a more accurate battery profile, the battery should be charged or discharged at a low rate. For example, the battery profile can be generated during charging or discharging at 0.05C.

[0051] For example, the curve acquisition unit 110 can receive the battery curve directly from the outside. That is, the curve acquisition unit 110 can obtain the battery curve by connecting to the outside via a wired and / or wireless connection and receiving the battery curve.

[0052] As another example, the curve acquisition unit 110 can receive battery information regarding the battery's voltage and capacity. Then, the curve acquisition unit 110 can generate a battery curve based on the received battery information. That is, the curve acquisition unit 110 can obtain a battery curve by directly generating a battery curve based on the battery information.

[0053] The curve acquisition unit 110 can be connected to communicate with the curve adjustment unit 120. For example, the curve acquisition unit 110 can be connected to the curve adjustment unit 120 via wired and / or wireless means. The curve acquisition unit can send the acquired battery curve to the curve adjustment unit 120.

[0054] The curve adjustment unit 120 can be configured to adjust a preset first reference curve Rp and a second reference curve Rn to correspond to the battery curve, and generate a first curve Rp' based on the adjustment result.

[0055] Here, the first reference curve Rp is a reference positive electrode curve, and can be a curve representing the correspondence between the capacity and voltage of a reference positive electrode cell pre-defined as corresponding to the positive electrode of the battery. For example, the reference positive electrode cell can be the positive electrode of a button cell or a three-electrode cell. As a specific example, the first reference curve Rp can be pre-defined to correspond to the positive electrode of a battery in the BOL (Burning Online) state. That is, the first reference curve Rp can be estimated as the positive electrode curve of a battery in the BOL state.

[0056] Furthermore, the second reference curve Rn is a reference negative electrode curve, and can be a curve representing the correspondence between the capacity and voltage of a reference negative electrode cell pre-defined as corresponding to the negative electrode of the battery. For example, the reference negative electrode cell can be the negative electrode of a button cell or a three-electrode cell. As a specific example, the second reference curve Rn can be pre-defined to correspond to the negative electrode of a battery in the BOL state. That is, the second reference curve Rn can be estimated as the negative electrode curve of a battery in the BOL state.

[0057] Specifically, the curve adjustment unit 120 can adjust the first reference curve Rp and the second reference curve Rn to correspond to the battery curve. More specifically, the curve adjustment unit 120 can generate adjusted first reference curve Rp and adjusted second reference curve Rn by adjusting the first reference curve Rp and the second reference curve Rn. Furthermore, the curve adjustment unit 120 can generate a comparison curve based on the adjusted first reference curve Rp and the adjusted second reference curve Rn. The curve adjustment unit 120 can adjust the first reference curve Rp and the second reference curve Rn until the comparison curve corresponds to the battery curve.

[0058] For example, the curve adjustment unit 120 can generate multiple comparison curves by shifting or scaling the capacity of the first reference curve Rp and the second reference curve Rn, and can specify the comparison curve with the smallest error to the battery curve among the multiple comparison curves. Then, the curve adjustment unit 120 can determine the adjusted first reference curve Rp and the adjusted second reference curve Rn corresponding to the specified comparison curve as the first curve Rp' and the second curve Rn', respectively. That is, the positive electrode curve representing the current state of the battery can be estimated as the first curve Rp', and the negative electrode curve can be estimated as the second curve Rn'.

[0059] Figure 2This is a diagram schematically illustrating the adjustment results of a first reference curve Rp and a second reference curve Rn according to an embodiment of the present disclosure.

[0060] Specifically, in Figure 2 In this embodiment, the curve adjustment unit 120 can generate the first curve Rp' and the second curve Rn' by adjusting the first reference curve Rp and the second reference curve Rn. That is, the first curve Rp' and the second curve Rn' are generated based on the organic relationship between the first reference curve Rp and the second reference curve Rn.

[0061] This will be discussed later. Figures 3 to 10 To describe a more specific embodiment: wherein the curve adjustment unit 120 determines the first curve Rp' of the battery by adjusting the first reference curve Rp and the second reference curve Rn to correspond to the battery curve.

[0062] The control unit 130 can be configured to diagnose the state of the battery based on the first feature value of the first feature point included in the first curve Rp'.

[0063] Specifically, the first curve Rp' includes a first characteristic point corresponding to the positive electrode participation start point (hereinafter referred to as pi) and a second characteristic point corresponding to the positive electrode participation termination point (hereinafter referred to as pf). Here, the positive electrode participation start point refers to the positive electrode point where the reaction begins during the charging process, or the positive electrode point where the reaction begins during the discharging process. The positive electrode participation termination point refers to the positive electrode point where the reaction ends during the charging process, or the positive electrode point where the reaction ends during the discharging process.

[0064] Similarly, the second curve Rn' includes a first characteristic point corresponding to the negative electrode participation start point (hereinafter referred to as ni) and a second characteristic point corresponding to the negative electrode participation termination point (hereinafter referred to as nf). Here, the negative electrode participation start point refers to the negative electrode point where the reaction begins during the charging process, or the negative electrode point where the reaction begins during the discharging process. The negative electrode participation termination point refers to the negative electrode point where the reaction ends during the charging process, or the negative electrode point where the reaction ends during the discharging process.

[0065] For example, in Figure 2 In one embodiment, the first curve Rp' may include a first feature point (pi') and a second feature point (pf'). The second curve Rn' may include a first feature point (ni') and a second feature point (nf').

[0066] The first characteristic value is a value representing at least one of the capacity, voltage, or SOC (state of charge) of the first characteristic point included in the first curve Rp'. Preferably, the first characteristic value is the SOC of the first characteristic point included in the first curve Rp'.

[0067] For example, the first eigenvalue can be calculated as the SOC of the capacity of the first feature point (pi') relative to the first curve Rp'. Assume the entire capacity range of the first curve Rp' is Qi [Ah] to Qf [Ah], and assume the capacity of the first feature point (pi') is Qt [Ah]. The first eigenvalue can be calculated using the formula “(Qt - Qi) ÷ (Qf - Qi) × 100”.

[0068] As another example, the first eigenvalue can also be calculated as the SOC of the capacity at the first characteristic point (pi') relative to the second curve Rn'. As yet another example, the first eigenvalue can also be calculated as the SOC of the capacity at the first characteristic point (pi') relative to the battery curve.

[0069] Specifically, the control unit 130 can be configured to diagnose the state of the battery as either normal or in a state of available lithium loss.

[0070] Here, "normal state" refers to a state where battery degradation occurs at a normal level. In other words, "normal state" means that the battery has degraded, but the degree of degradation is within a normal range. Furthermore, "available lithium loss state" refers to a state where lithium plating has occurred, where lithium metal is deposited on the surface of the battery's negative electrode.

[0071] The apparatus 100 for diagnosing a battery according to an embodiment of the present disclosure has the advantage that the state of the battery can be specifically diagnosed based on a first curve Rp' derived from the adjustment results of a first reference curve Rp and a second reference curve Rn. That is, since the degradation mode of the battery can be specifically diagnosed according to an embodiment of the present disclosure, the current state of the battery can be qualitatively diagnosed in a non-destructive manner.

[0072] Meanwhile, the control unit 130 included in the battery diagnostic device 100 may optionally include processors, application-specific integrated circuits (ASICs), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art, to execute the various control logics performed in this disclosure. Furthermore, when the control logic is implemented in software, the control unit 130 can be implemented as a collection of program modules. In this case, the program modules can be stored in a memory and executed by the control unit 130. The memory can be located inside or outside the control unit 130 and can be connected to the control unit 130 by various well-known means.

[0073] Furthermore, the device 100 for diagnosing the battery may further include a storage unit 140. The storage unit 140 may store data required for the operation and function of each component of the device 100 for diagnosing the battery, data generated during the execution of operations or functions, etc. The storage unit 140 is not particularly limited in its type, as long as it is a known information storage device capable of recording, erasing, updating, and retrieving data. As examples, the information storage device may include RAM, flash memory, ROM, EEPROM, registers, etc. In addition, the storage unit 140 may store program code that defines processes executable by the control unit 130.

[0074] Below is a specific example of the control unit 130 for diagnosing the state of the battery.

[0075] In one embodiment, the control unit 130 may diagnose the state of the battery based on the result of comparing a first characteristic value with a first standard value.

[0076] Here, the first standard value can be preset as the first characteristic value of the reference battery. Furthermore, the reference battery is a battery compared to a battery according to an embodiment of this disclosure, and refers to a battery that has experimentally or theoretically undergone only normal levels of degradation.

[0077] Specifically, in the state of the battery, the first characteristic value may change sensitively when available lithium is lost. That is, the change in the first characteristic value can be used to determine whether available lithium has been lost. Therefore, the control unit 130 can diagnose the state of the battery by comparing the magnitude of the first standard value with the first characteristic value.

[0078] For example, control unit 130 can be configured to diagnose the battery state as a state of available lithium loss if the first characteristic value exceeds a first standard value. Conversely, control unit 130 can be configured to diagnose the battery state as a normal state if the first characteristic value is less than or equal to the first standard value.

[0079] In another embodiment, the control unit 130 may calculate the available lithium loss rate of the battery based on a first feature value, and diagnose the battery status based on the calculated available lithium loss rate.

[0080] The control unit 130 can be configured to calculate the available lithium loss rate based on a preset first reference value, a preset second reference value, and a first characteristic value. Here, the available lithium loss rate represents the degree to which the amount of lithium available for charging and discharging has been lost. For example, if the available lithium loss rate is 1%, it means that 1% of the lithium designed to be usable has been lost and is unusable. In other words, 1% of the lithium designed to be usable may have been deposited as metal on the negative electrode of the battery.

[0081] In one embodiment, the first reference value can be preset as the State of Charge (SOC) of the first reference point (pi0) included in the first reference curve Rp. Here, the first reference point (pi0) of the first reference curve Rp corresponds to the first characteristic point (pi') of the first curve Rp'. Specifically, since the first reference curve Rp corresponds to the positive electrode curve of the battery in the BOL state, the first reference point (pi0) corresponds to the positive electrode participation start point of the battery in the BOL state.

[0082] For example, in Figure 2 In one embodiment, a first reference point (pi0) of the first reference curve Rp corresponds to a first feature point (pi') of the first curve Rp'. Furthermore, the first reference value can be calculated as the State of Charge (SOC) of the capacity at the first reference point (pi0) relative to the first reference curve Rp.

[0083] Furthermore, the second reference value can be preset as the SOC of the second reference point (pf0) included in the first reference curve Rp. Here, the second reference point (pf0) of the first reference curve Rp corresponds to the second characteristic point (pf') of the first curve Rp'. Specifically, since the first reference curve Rp corresponds to the positive electrode curve of the battery in the BOL state, the second reference point (pf0) corresponds to the positive electrode termination point of the battery in the BOL state.

[0084] For example, in Figure 2 In this embodiment, the second reference point (pf0) of the first reference curve Rp corresponds to the second feature point (pf') of the first curve Rp'. Furthermore, the second reference value can be calculated as the State of Charge (SOC) of the capacity at the second reference point (pf0) relative to the first reference curve Rp.

[0085] Specifically, the control unit 130 can calculate a first difference between a first reference value and a second reference value, calculate a second difference between a first feature value and a first reference value, and calculate the ratio of the second difference to the first difference to calculate the available lithium loss rate.

[0086] For example, the control unit 130 can use the following formula 1 to calculate the available lithium loss rate.

[0087] [Formula 1]

[0088]

[0089] Here, L Li pi represents the available lithium loss rate. BOL pf is the first reference value for the first reference curve Rp. BOL Let pi be the second reference value of the first reference curve Rp, and pi MOL Let Rp' be the first characteristic value of the first curve.

[0090] In another embodiment, the first reference value is the SOC of a first reference point included in the first reference curve Rp and the SOC of a first reference point included in the second reference curve Rn. Specifically, since the second reference curve Rn corresponds to the negative electrode curve of the battery in the BOL state, the first reference point corresponds to the negative electrode participation start point of the battery in the BOL state.

[0091] For example, in Figure 2 In one embodiment, the first reference value can be calculated as the SOC of the capacity at the first reference point (ni0) relative to the second reference curve Rn.

[0092] Furthermore, the second reference value is the SOC of the second reference point (nf0) included in the second reference curve Rn. Specifically, since the second reference curve Rn corresponds to the negative electrode curve of the battery in the BOL state, the second reference point (nf0) corresponds to the negative electrode participation termination point of the battery in the BOL state.

[0093] For example, in Figure 2 In one embodiment, the second reference value can be calculated as the SOC of the capacity of the second reference point (nf0) relative to the second reference curve Rn.

[0094] Specifically, the control unit 130 can calculate a first difference between a first reference value and a second reference value of the second reference curve Rn, calculate a second difference between a first characteristic value and a first reference value of the first reference curve Rp, and calculate the ratio of the second difference to the first difference to calculate the available lithium loss rate.

[0095] For example, the control unit 130 can use the following formula 2 to calculate the available lithium loss rate.

[0096] [Formula 2]

[0097]

[0098] Here, L Li pi represents the available lithium loss rate. BOL ni is the first reference value for the first reference curve Rp. BOL nf is the first reference value for the second reference curve Rn. BOL Let pi be the second reference value of the second reference curve Rn, and pi MOL Let Rp' be the first characteristic value of the first curve.

[0099] For example, if the first reference value of the first reference curve Rp is set to the capacity of the first reference point (pi0) for the capacity of the first reference curve Rp, then the first reference value of the second reference curve Rn can also be set to the capacity of the first reference point (ni0) for the capacity of the first reference curve Rp. As another example, if the first reference value of the first reference curve Rp is set to the capacity of the first reference point (pi0) for the capacity of the second reference curve Rn, then the first reference value of the second reference curve Rn can also be set to the capacity of the first reference point (ni0) for the capacity of the second reference curve Rn. That is, since the difference between the capacities of the first and second reference points of the first reference curve Rp is the same as the difference between the capacities of the first and second reference points of the second reference curve Rn, the difference between the first and second reference values ​​of the first reference curve Rp is the same as the difference between the first and second reference values ​​of the second reference curve Rn. In other words, in Formulas 1 and 2, "pf"... BOL -Pi BOL " can be replaced with "nf BOL - ni BOL ".

[0100] exist Figure 2 In the embodiment, the capacity difference between the first reference point (pi0) and the second reference point (pf0) of the first reference curve Rp is equal to the capacity difference between the first reference point (ni0) and the second reference point (nf0) of the second reference curve Rn. Therefore, the difference between the first reference value and the second reference value of the first reference curve Rp (pf0) is equal to the capacity difference between the first reference point (ni0) and the second reference point (nf0) of the second reference curve Rn. BOL -Pi BOL ) equals the difference between the first reference value and the second reference value of the second reference curve Rn (nf) BOL - ni BOL ).

[0101] The control unit 130 can be configured to compare the calculated available lithium loss rate with a preset second standard value.

[0102] Specifically, the second standard value can be preset as the available lithium loss rate of a reference battery. As mentioned above, a reference battery is a battery compared with a battery according to an embodiment of this disclosure, and is meant to be a battery that has only undergone normal degradation experimentally or theoretically. For example, the available lithium loss rate of the reference battery can be calculated based on a first reference value, a second reference value, and a first characteristic value of the reference battery, and the calculated available lithium loss rate can be set as the second standard value. As another example, the available lithium loss rate of the reference battery can be calculated by directly measuring the amount of lithium metal deposited on the negative electrode surface of the reference battery, and the calculated available lithium loss rate can be set as the second standard value.

[0103] The control unit 130 can be configured to diagnose the state of the battery based on the comparison results.

[0104] For example, control unit 130 can be configured to diagnose the battery state as a state of available lithium loss if the available lithium loss rate exceeds a second standard value. Conversely, control unit 130 can be configured to diagnose the battery state as a normal state if the available lithium loss rate is less than or equal to the second standard value. That is, if the available lithium loss rate of the battery is greater than the available lithium loss rate of a reference battery, control unit 130 can diagnose the battery state as a state of available lithium loss.

[0105] In another embodiment, the control unit 130 can diagnose the state of the battery by simultaneously considering the result of comparing a first characteristic value with a first standard value and the result of comparing the battery's available lithium loss rate with a second standard value.

[0106] The control unit 130 can diagnose the state of the battery by considering a first result of comparing a first characteristic value with a first standard value and a second result of comparing the battery's available lithium loss rate with a second standard value.

[0107] For example, if both the first and second results are normal, the control unit 130 can diagnose the battery's state as normal.

[0108] As another example, if both the first and second results indicate a state of available lithium loss, the control unit 130 can diagnose the battery state as a state of available lithium loss.

[0109] As another example, if the first result and the second result are different from each other and the second result is a state of available lithium loss, the control unit 130 can diagnose the state of the battery as a state of available lithium loss.

[0110] As another example, if the first and second results differ from each other and the second result is a normal state, the control unit 130 can diagnose the battery state as pending. The control unit 130 can determine that the battery state is not a state of available lithium loss, but a state that requires additional diagnosis. In this case, diagnostic fault codes (DTCs), flags, messages, or logs indicating the need for further diagnosis of the battery can be recorded.

[0111] Figure 3 This is a graph used as a reference to explain examples of each of the first and second reference curves. Figure 3 In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage (V).

[0112] refer to Figure 3The storage unit 140 can store a first reference curve Rp and a second reference curve Rn. The reference cell can be a button cell including a positive electrode half-cell and a negative electrode half-cell, or a three-electrode cell.

[0113] The first reference curve Rp can be a curve representing the relationship between the positive electrode voltage and capacity of a reference cell. The positive electrode voltage of the reference cell refers to the potential difference between the potential of the reference electrode (not shown) and the potential of the positive electrode of the reference cell.

[0114] The second reference curve Rn can be a curve representing the relationship between the negative electrode voltage and capacitance of a reference cell. The negative electrode voltage of the reference cell refers to the potential difference between the potential of the reference electrode and the potential of the negative electrode of the reference cell.

[0115] The positive and negative voltages can each be either closed-circuit voltages or open-circuit voltages (OCVs).

[0116] The closed-circuit voltages of the positive and negative terminals of the reference cell can be obtained using either a first charging protocol or a first discharging protocol. The first charging protocol can be a constant current charging method using a first current rate. The first discharging protocol can be a constant current discharging method using a first current rate. For example, while continuously charging the reference cell using the first charging protocol or continuously discharging the reference cell using the first discharging protocol, the closed-circuit voltages of the positive and negative terminals of the reference cell, measured periodically or non-periodically, can be recorded as the positive and negative terminal voltages of the reference cell.

[0117] A second charging protocol or a second discharging protocol can be used to obtain the open-circuit voltage of each of the positive and negative terminals of the reference cell. The second charging protocol can be an intermittent charging method in which constant current charging using a second current rate is alternately performed with pauses. The second discharging protocol can be an intermittent charging method in which constant current discharging using a second current rate is alternately performed with pauses. The second current rate (e.g., 3.0C) can be predetermined to be greater than the first current rate (e.g., 0.05C).

[0118] For example, when the constant current charging time via the second charging protocol has elapsed for a set time or the charging capacity of the reference cell has increased by a set capacity, charging of the reference cell can be stopped for a predetermined pause time, and then constant current charging can be resumed. The charging capacity can be calculated by periodically or non-periodically accumulating the sampled values ​​of the charging current via the first or second charging protocol.

[0119] As another example, when the discharge time of the constant current discharge via the second discharge protocol has elapsed for a set time or the discharge capacity of the reference cell has decreased by a set capacity, the discharge to the reference cell can be stopped for a predetermined pause time, and then the constant current discharge can be resumed. The discharge capacity can be calculated by periodically or non-periodically accumulating the sampled values ​​of the discharge current via the first or second discharge protocol.

[0120] At this point, the open-circuit voltage of each of the positive and negative terminals of the reference cell, measured at a specific timing point during each pause, can be recorded as the positive and negative terminal voltages of the reference cell.

[0121] For ease of explanation, in Figures 3 to 10 In the diagram, we assume the horizontal axis represents the charging capacity.

[0122] At least one of the first reference curve Rp and the second reference curve Rn can be aligned along the horizontal axis, such that a portion of the common capacity range of the two curves Rp and Rn is included. Figure 3 The results of the synthesis (with values ​​of 5 to 50 Ah) matched the third reference curve R. Figure 3 An example is shown in which the second reference curve Rn is aligned by shifting the second reference curve Rn to the right with the starting point of the first reference curve Rp (the point corresponding to capacity 0) as the reference point.

[0123] from Figure 3 It can be confirmed that the two ends of the first reference curve Rp and the second reference curve Rn are not aligned. That is, the capacitance range of the first reference curve Rp does not match the capacitance range of the second reference curve Rn, and they only partially overlap. Therefore, the third reference curve R represents the full-cell voltage of the reference cell within a portion of the common capacitance range of the first reference curve Rp and the second reference curve Rn. In other words, the third reference curve R is an example of a full-cell voltage curve obtained by directly subtracting a portion of the second reference curve Rn from a portion of the first reference curve Rp.

[0124] The third reference curve R can represent the correspondence between the capacity of a newly proven good battery cell and the overall cell voltage. That is, the reference cell has the same level of positive and negative electrode performance as the newly proven good battery cell.

[0125] The third reference curve R can represent the correspondence between the voltage and capacity of the reference cell, at least within the voltage range of interest (e.g., 3.0 to 4.0 V). The lower and upper limits of the voltage range of interest can be defined by a first set voltage ( Figure 3 The middle voltage is 3.0 V) and the second set voltage ( Figure 3 (V is 4.0 V).

[0126] The State of Charge (SOC) can be set to 0% when the total voltage of any cell, including the reference cell, equals a first set voltage. The SOC can be set to 100% when the total voltage of any cell, including the reference cell, equals a second set voltage. Figure 3 The reference cell can be charged from a fully discharged state (SOC 0%) to a fully charged state (SOC 100%) with a charging capacity of 45 Ah.

[0127] In this specification, the positive electrode participation start point on the positive electrode curve of any battery cell represents the positive electrode voltage when the total voltage of the corresponding battery cell matches the first set voltage. Similarly, the negative electrode participation start point on the negative electrode curve of the corresponding battery cell represents the negative electrode voltage when the total voltage of the corresponding battery cell matches the first set voltage. Therefore, the voltage difference between the positive electrode participation start point and the negative electrode participation start point is equal to the first set voltage.

[0128] Furthermore, the positive electrode participation termination point on the positive electrode curve of any battery cell represents the positive electrode voltage when the total voltage of the corresponding battery cell matches the second set voltage. Similarly, the negative electrode participation termination point on the negative electrode curve of the corresponding battery cell represents the negative electrode voltage when the total voltage of the corresponding battery cell matches the second set voltage. Therefore, the voltage difference between the positive and negative electrode participation termination points is equal to the second set voltage.

[0129] In the storage unit 140, information representing the voltage of each of the following reference positive electrode participation start point (pi0), reference positive electrode participation end point (pf0), reference negative electrode participation start point (ni0), and reference negative electrode participation end point (nf0) can be pre-recorded. The reference positive electrode participation start point (pi0) and reference positive electrode participation end point (pf0) are the positive electrode participation start point and positive electrode participation end point on the first reference curve Rp, respectively. The reference negative electrode participation start point (ni0) and reference negative electrode participation end point (nf0) are the negative electrode participation start point and negative electrode participation end point on the second reference curve Rn, respectively.

[0130] The voltage difference between the reference positive terminal participation start point (pi0) and the reference negative terminal participation start point (ni0) can be equal to a first set voltage (e.g., 3.0 V). The voltage difference between the reference positive terminal participation end point (pf0) and the reference negative terminal participation end point (nf0) can be equal to a second set voltage (e.g., 4.0 V).

[0131] Figure 4 This is an example graph used to interpret the battery curves of the target cell. Figure 4 In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage.

[0132] refer to Figure 4 The curve adjustment unit 120 can generate a battery curve M, which represents the correspondence between the capacity and terminal voltage (also known as the "total cell voltage") of the battery cell to be diagnosed (hereinafter referred to as the "target cell"). Here, the terminal voltage refers to the voltage (CCV or OCV) across the two ends of the target cell, and is distinguished from the positive and negative electrode voltages described above. In other words, the terminal voltage of the target cell can be said to be the difference between the positive and negative electrode voltages of the target cell.

[0133] The battery curve M can be generated using the first charging protocol, the first discharging protocol, the second charging protocol, or the second discharging protocol described above. Similar to the third reference curve R, the battery curve M can represent the voltage-capacity relationship of the target cell, at least within the voltage range of interest (e.g., 3.0 to 4.0 V).

[0134] If the first reference curve Rp and the second reference curve Rn are obtained through the first charging protocol (or the first discharging protocol), then the battery curve M can also be based on the voltage time series and capacity time series collected through the charging process (or discharging process) carried out with the first charging protocol (or the first discharging protocol).

[0135] If the first reference curve Rp and the second reference curve Rn are obtained through the second charging protocol (or the second discharging protocol), then the battery curve M can also be based on the voltage time series and capacity time series collected through the charging process (or discharging process) carried out with the second charging protocol (or the second discharging protocol).

[0136] The voltage time series represents the change of the terminal voltage of the target cell over time. The capacity time series represents the change of the capacity of the target cell over time while it is being charged or discharged through a first charging protocol, a first discharging protocol, a second charging protocol, or a second discharging protocol.

[0137] When referring to the above text Figure 3 Compared to the third reference curve R, the battery curve M can represent the actual correspondence between the capacity of the target cell and the voltage of the entire cell. The target cell can be a new cell that needs to be verified as good, or a cell that has been verified as good but has deteriorated and is no longer new.

[0138] Therefore, as Figure 4As shown, there may be some differences between battery curve M and the third reference curve R. For example, at the same capacity value, the voltage of battery curve M is higher than that of the third reference curve R. This is due to manufacturing defects in the target cell, loss of positive electrode capacity, loss of negative electrode capacity, and / or loss of available lithium. It is evident that as the target cell deteriorates through repeated charging and discharging, the difference between battery curve M and the third reference curve R will gradually increase. Figure 4 , and reference Figure 3 Unlike the reference cell, the target cell requires 40 Ah of charging capacity to go from a fully discharged state (SOC 0%) to a fully charged state (SOC 100%), which is 5 Ah less than the charging capacity required to fully charge the reference cell.

[0139] At the same time, Figure 3 and Figure 4 In this embodiment, Ah is used as the unit on the horizontal axis, but this unit can also be represented in different forms. For example, instead of Ah, a percentage (%) representing SOC (State of Charge) can be used as the unit on the horizontal axis.

[0140] After the battery curve M is generated, the curve adjustment unit 120 can be configured to compare the battery curve M with at least one comparison curve. Here, the comparison curve can be the result of the following operation: adjusting a first reference curve Rp and a second reference curve Rn stored in the storage unit 140 to generate a first adjusted curve and a second adjusted curve, and then synthesizing (combining) the first adjusted curve and the second adjusted curve. Here, the first adjusted curve is the result of adjusting the first reference curve Rp, and is the adjusted positive electrode curve. The second adjusted curve is the result of adjusting the second reference curve Rn, and is the adjusted negative electrode curve.

[0141] That is, when the third reference curve R is the result of subtracting a portion of the second reference curve Rn from a portion of the first reference curve Rp, then the comparison curve can be said to be the result of subtracting a portion of the second adjusted curve from a portion of the first adjusted curve.

[0142] The curve adjustment unit 120 can generate at least one comparison curve by directly adjusting the first reference curve Rp and the second reference curve Rn. Alternatively, at least one comparison curve can be pre-established based on the first reference curve Rp and the second reference curve Rn and stored in the storage unit 140. In this case, the curve adjustment unit 120 can also obtain the comparison curve by accessing the storage unit 140 and reading the comparison curve.

[0143] The curve adjustment unit 120 can generate multiple comparison curves based on the first reference curve Rp and the second reference curve Rn by repeatedly adjusting each of the first reference curve Rp and the second reference curve Rn to several levels and then synthesizing them.

[0144] The curve adjustment unit 120 can specify any comparison curve among multiple comparison curves that has the smallest error with the battery curve M. Then, the curve adjustment unit 120 can determine that the first adjusted curve and the second adjusted curve mapped to the specified comparison curve are the first curve and the second curve of the target cell. Here, the first curve is estimated as the positive electrode curve of the target cell, and the second curve is estimated as the negative electrode curve of the target cell.

[0145] In this regard, various methods known at the time of this disclosure can be used to determine the error between two curves, each of which can be represented in a two-dimensional coordinate system. For example, the integral of the absolute values ​​of the regions between the two curves, or the RMSE (root mean square error), can be used as the error between the two curves.

[0146] According to this configuration, various state information about the target cell can be obtained based on the finally determined first and second curves. The finally determined first and second curves can be mapped to a comparison curve mapped with minimal error. In particular, the comparison curve determined by the finally determined first and second curves can be said to be almost identical to the battery curve M in shape, etc.

[0147] Therefore, according to this disclosure, even without disassembling the target cell or manufacturing it as a three-electrode cell, positive and negative electrode curves for the target cell can be obtained.

[0148] If the target cell is a new battery cell, the first curve and the second curve can be analyzed to more easily diagnose whether a defect has occurred in the target cell, and if so, what type of defect it is.

[0149] If the target cell is a battery cell that has been proven to be a good product and is currently in use, the degree of degradation of the target cell can be identified by the first curve and the second curve, according to the degradation items.

[0150] Furthermore, according to one embodiment of this disclosure, the positive electrode curve (first curve) and negative electrode curve (second curve) of the target cell can be obtained in a simple manner. This disclosure can be achieved even if only one first reference curve Rp and one second reference curve Rn are stored in the storage cell 140. That is, it is not necessary to store multiple first reference curves Rp and / or multiple second reference curves Rn in the storage cell 140. Therefore, the storage capacity of the storage cell 140 does not need to be high, and the extensive pre-testing required to ensure multiple first reference curves Rp and / or multiple second reference curves Rn is unnecessary.

[0151] Figures 5 to 7 This is a diagram that is referenced to illustrate an example of a process for generating a comparison curve for comparison with a battery curve according to an embodiment of the present disclosure.

[0152] For reference Figures 5 to 7 The process of generating the comparison curves described is executed in the following order: First routine (see...) Figure 5 The first routine sets four points (positive participation start point, positive participation end point, negative participation start point, negative participation end point) to correspond to the voltage range of interest; the second routine (see...) Figure 6 The second routine performs a curve shift; and the third routine (see...) Figure 7 The third routine performs capacity scaling. That is, the process of generating a comparison curve according to an embodiment of this disclosure includes the first to third routines.

[0153] First, refer to Figure 5 The first reference curve Rp and the second reference curve Rn are related to Figure 3 The same as those shown.

[0154] The curve adjustment unit 120 determines the positive electrode participation start point (pi), positive electrode participation end point (pf), negative electrode participation start point (ni), and negative electrode participation end point (nf) on the first reference curve Rp and the second reference curve Rn.

[0155] The positive electrode participation initiation point (pi) and the negative electrode participation initiation point (ni) depend on the other.

[0156] For example, the curve adjustment unit 120 can divide the positive voltage range of the first reference curve Rp from the start point to the end point (or the second set voltage) into multiple micro-voltage segments, and then set the boundary point of two adjacent micro-voltage segments as the positive participation start point (pi). Each micro-voltage segment can have a predetermined size (e.g., 0.01 V). Then, the curve adjustment unit 120 can set the point on the second reference curve Rn that is smaller than the positive participation start point (pi) by a first set voltage (e.g., 3 V) as the negative participation start point (ni).

[0157] As another example, the curve adjustment unit 120 can divide the negative voltage range of the second reference curve Rn from the start point to the end point into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments as the negative participation start point (ni). Then, the curve adjustment unit 120 can search for a point in the first reference curve Rp that is larger than the negative participation start point (ni) by a first set voltage, and set the searched point as the positive participation start point (pi).

[0158] The positive electrode participates in the termination point (pf) and the negative electrode participates in the termination point (nf), which depends on the other.

[0159] For example, the curve adjustment unit 120 can divide the voltage range of the first reference curve Rp from the second set voltage to the termination point into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments among the multiple micro-voltage segments as the positive terminal participation termination point (pf). Then, the curve adjustment unit 120 can set the point on the second reference curve Rn that is smaller than the positive terminal participation termination point (pf) by the second set voltage (e.g., 4 V) as the negative terminal participation termination point (nf).

[0160] As another example, the curve adjustment unit 120 can divide the negative voltage range of the second reference curve Rn from the start point to the end point into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments among the multiple micro-voltage segments as the negative participation termination point (nf). Then, the curve adjustment unit 120 can search for a point in the first reference curve Rp that is larger than the negative participation termination point (nf) by a second set voltage, and set the searched point as the positive participation termination point (pf).

[0161] Once the positive electrode participation start point (pi), positive electrode participation end point (pf), negative electrode participation start point (ni), and negative electrode participation end point (nf) are determined, the curve adjustment unit 120 shifts at least one of the first reference curve Rp and the second reference curve Rn to the left or right along the horizontal axis.

[0162] refer to Figure 6 The curve adjustment unit 120 can shift the first reference curve Rp to the left (low capacity side), shift the second reference curve Rn to the right (high capacity side), or both, so that the capacity value of the positive electrode participation start point (pi) matches the capacity value of the negative electrode participation start point (ni).

[0163] Alternatively, the curve adjustment unit 120 can shift the first reference curve Rp to the left, shift the second reference curve Rn to the right, or both, so that the voltage at the positive terminal participation termination point (pf) matches the voltage at the negative terminal participation termination point (nf).

[0164] Figure 6 The following scenario illustrates where only the first reference curve Rp is shifted to the left to generate an adjusted first reference curve Rp', resulting in the voltage at the positive electrode participation initiation point (pi') matching the voltage at the negative electrode participation initiation point (ni). The adjusted first reference curve Rp' is the result of applying an adjustment process to the first reference curve Rp to the left, using the voltage difference between the positive electrode participation initiation point (pi) and the negative electrode participation initiation point (ni). Therefore, the two points (pi, pi') differ only in capacitance values, while their voltages are the same. Similarly, the two points (pf, pf') differ only in capacitance values, while their voltages are the same.

[0165] When an adjustment result curve Rp' or Rn is obtained by shifting at least one of the first reference curve Rp and the second reference curve Rn, the curve adjustment unit 120 scales the capacity range of at least one of the adjustment result curves Rp' or Rn.

[0166] according to Figure 6 In the example shown, the curve adjustment unit 120 performs an additional adjustment process along the horizontal axis to shrink or expand at least one of the adjusted first reference curve Rp' and the second reference curve Rn.

[0167] refer to Figure 7 The curve adjustment unit 120 can generate the adjusted first reference curve Rp'' by shrinking or expanding the adjusted first reference curve Rp', such that the capacity range between two points (pi', pf') of the adjusted first reference curve Rp' matches the capacity range of the battery curve M. In this case, one of these two points (pi', pf') can be fixed. Therefore, the capacity difference between these two points (pi', pf'') of the adjusted first reference curve Rp'' can match the capacity range of the battery curve M.

[0168] Furthermore, the curve adjustment unit 120 can generate the adjusted second reference curve Rn' by shrinking or expanding the second reference curve Rn, such that the capacity range between two points (ni, nf) on the second reference curve Rn matches the capacity range of the battery curve M. In this case, one of these two points (ni, nf) can be fixed. Therefore, the capacity difference between these two points (ni, nf') on the adjusted second reference curve Rn' can match the capacity range of the battery curve M.

[0169] exist Figure 7 In the middle, the adjusted first reference curve Rp'' is... Figure 6 The adjusted first reference curve Rp' shown is the result of shrinking, and the adjusted second reference curve Rn' is... Figure 6 The result of extending the second reference curve Rn shown.

[0170] The positive electrode participation termination point (pf'') on the adjusted first reference curve Rp'' corresponds to the positive electrode participation termination point (pf') on the adjusted first reference curve Rp'. The negative electrode participation termination point (nf') on the adjusted second reference curve Rn' corresponds to the negative electrode participation termination point (nf) on the second reference curve Rn.

[0171] The capacity difference between the positive electrode participation start point (pi') and the positive electrode participation termination point (pf'') of the adjusted first reference curve Rp'' corresponds to the size of the capacity range of the battery curve M. Similarly, the capacity difference between the negative electrode participation start point (ni) and the negative electrode participation termination point (nf') of the adjusted second reference curve Rn' corresponds to the size of the capacity range of the battery curve M.

[0172] Furthermore, the capacity range determined by the two points (pi', pf'') of the adjusted first reference curve Rp'' matches the capacity range determined by the two points (ni, nf') of the adjusted second reference curve Rn'. The curve adjustment unit 120 can generate a comparison curve S by subtracting the curve between the two points (pi', pf'') of the adjusted first reference curve Rp'' from the curve between the two points (ni, nf') of the adjusted second reference curve Rn'.

[0173] The curve adjustment unit 120 can calculate the error (curve error) between the comparison curve S and the third reference curve R.

[0174] The curve adjustment unit can map at least two of the adjusted first reference curve Rp'', the adjusted second reference curve Rn', the positive electrode participation start point (pi'), the positive electrode participation end point (pf''), the negative electrode participation start point (ni), the negative electrode participation end point (nf'), the first scaling factor, the second scaling factor, the comparison curve S, and the curve error to each other, and record them in the storage unit 140.

[0175] The first scaling factor represents the ratio of the capacity difference between two points (pi', pf'') to the capacity difference between two points (pi0, pf0). The second scaling factor represents the ratio of the capacity difference between two points (ni, nf') to the capacity difference between two points (ni0, nf0). That is, the first scaling factor is the rate of change of the adjusted first reference curve Rp'' relative to the first reference curve Rp, which is the positive electrode rate of change. The second scaling factor is the rate of change of the adjusted second reference curve Rn' relative to the second reference curve Rn, which is the negative electrode rate of change.

[0176] Meanwhile, as mentioned above, when the positive voltage range of the first reference curve Rp is divided into multiple micro-voltage segments, the boundary point of two adjacent micro-voltage segments among the multiple micro-voltage segments can be set as the positive participation starting point (pi).

[0177] For example, if the positive voltage range of the first reference curve Rp is divided into 100 micro-voltage ranges, then the number of boundary points that can be set as the positive participation start point (pi) can be 100. Furthermore, if the voltage range in the first reference curve Rp that is higher than or equal to the second set voltage is divided into 40 micro-voltage ranges, then the number of boundary points that can be set as the positive participation termination point (pf) can be 40. In this case, up to 4000 different comparison curves can be generated.

[0178] Of course, those skilled in the art will readily understand that as the size of the micro-voltage segment decreases, the maximum number of comparison curves that can be generated increases, and conversely, as the size of the micro-voltage segment increases, the maximum number of comparison curves that can be generated decreases.

[0179] The curve adjustment unit 120 can identify the minimum value among the curve errors of the multiple comparison curves generated as described above, and then obtain information mapped to the minimum curve error from the storage unit 140 (e.g., at least one of positive pole participation start point, positive pole participation end point, negative pole participation start point, negative pole participation end point, first scaling factor and second scaling factor).

[0180] Figures 8 to 10This is a diagram that is referenced to explain another example of a process for generating a comparison curve for comparison with a battery curve according to an embodiment of the present disclosure. For reference, according to Figures 8 to 10 The embodiments are independent of those based on Figures 5 to 7 Implementation examples. Therefore, in the description according to... Figures 5 to 7 Implementation examples and according to Figures 8 to 10 The terms or reference numerals commonly used in the embodiments described should be understood as being limited to each embodiment only.

[0181] For reference Figures 8 to 10 The process of generating the comparison curve described is executed in the following order: Fourth routine (see...) Figure 8 The fourth routine is used to perform capacity scaling; the fifth routine (see...) Figure 9 The fifth routine is used to set four points (positive electrode participation start point, positive electrode participation end point, negative electrode participation start point, negative electrode participation end point); and the sixth routine (see...) Figure 10 The sixth routine is used to perform curve shifting. That is, the process of generating the comparison curve according to another embodiment of this disclosure includes the fourth to sixth routines.

[0182] refer to Figure 8 The first reference curve Rp and the second reference curve Rn are related to Figure 3 The same as those shown.

[0183] The curve adjustment unit 120 applies the first scaling factor and the second scaling factor selected from the scaling value range to the first reference curve Rp and the second reference curve Rn, respectively, to generate the adjusted first reference curve Rp' and the adjusted second reference curve Rn'.

[0184] The scaling range can be predetermined or varied according to the ratio of the capacity range of the battery curve M to the capacity range of the third reference curve R. For example, when values ​​spaced 0.1% apart within the scaling range (e.g., 90%, 90.1%, 90.2%, ..., 98.9%, 99%) can be selected as the first and second scaling factors, 91 values ​​can be selected as the first and second scaling factors, respectively. In this case, a maximum of 8281 adjusted curve pairs can be generated based on 8281 (91 × 91) adjustment levels (combinations of the first and second scaling factors). An adjusted curve pair refers to a combination of the first and second adjusted curves.

[0185] Figure 8The adjusted first reference curve Rp' and adjusted second reference curve Rn' shown illustrate the results of applying a first scaling factor of less than 100% and a second scaling factor to the first reference curve Rp and the second reference curve Rn, respectively.

[0186] Since the first scaling factor and the second scaling factor are less than 100%, the adjusted first reference curve Rp' is the first reference curve Rp shrunk along the horizontal axis, and the adjusted second reference curve Rn' is also the second reference curve Rn shrunk along the horizontal axis. To help understand, as an example, the starting points of the first reference curve Rp and the second reference curve Rn are fixed, while the rest are shrunk to the left along the horizontal axis.

[0187] In the example above, the scaling factor is described as less than 100%, but the scaling factor can also be greater than or equal to 100%.

[0188] refer to Figure 9 The curve adjustment unit 120 determines the positive electrode participation start point (pi'), positive electrode participation end point (pf'), negative electrode participation start point (ni'), and negative electrode participation end point (nf') on the adjusted first reference curve Rp' and the adjusted second reference curve Rn'.

[0189] Either the positive electrode participation start point (pi') or the negative electrode participation start point (ni') can depend on the other. Similarly, either the positive electrode participation termination point (pf') or the negative electrode participation termination point (nf') can depend on the other. Furthermore, either the positive electrode participation start point (pi') or the positive electrode participation termination point (pf') can be set based on the other.

[0190] That is, when one of the positive electrode participation start point (pi'), positive electrode participation end point (pf'), negative electrode participation start point (ni'), and negative electrode participation end point (nf') is set, the other three points can be automatically set by the size of the capacity range of the battery curve M (e.g., SOC 0% to 100% charging capacity), the first set voltage, the second set voltage, and / or the capacity range of the battery curve M.

[0191] For example, the curve adjustment unit 120 can divide the positive voltage range of the adjusted first reference curve Rp' from the start point to the end point (or the second set voltage) into multiple micro-voltage segments, and then set the boundary point of two adjacent micro-voltage segments as the positive participation start point (pi'). Then, the curve adjustment unit 120 can set the point on the adjusted second reference curve Rn that is smaller than the positive participation start point (pi') by a first set voltage (e.g., 3V) as the negative participation start point (ni').

[0192] As another example, the curve adjustment unit 120 can divide the negative voltage range of the adjusted second reference curve Rn' from the start point to the end point into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments as the negative participation start point (ni'). Then, the curve adjustment unit 120 can search for a point in the adjusted first reference curve Rp' that is larger than the negative participation start point (ni') by a first set voltage, and set the searched point as the positive participation start point (pi').

[0193] As another example, the curve adjustment unit 120 can divide the voltage range from the second set voltage to the termination point of the adjusted first reference curve Rp' into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments among the multiple micro-voltage segments as the positive terminal participation termination point (pf'). Then, the curve adjustment unit 120 can search for points in the adjusted second reference curve Rn' that are smaller than the second set voltage (e.g., 4 V) than the positive terminal participation termination point (pf'), and set the searched point as the negative terminal participation termination point (nf').

[0194] As another example, the curve adjustment unit 120 can divide the negative voltage range of the adjusted second reference curve Rn' from the start point to the end point into multiple micro-voltage segments of a predetermined size, and then set the boundary point of two adjacent micro-voltage segments as the negative participation termination point (nf'). Then, the curve adjustment unit 120 can search for a point in the adjusted first reference curve Rp' that is larger than the negative participation termination point (nf') by a second set voltage, and set the searched point as the positive participation termination point (pf').

[0195] If one of the positive electrode participation start point (pi'), positive electrode participation end point (pf'), negative electrode participation start point (ni'), and negative electrode participation end point (nf') is determined, the curve adjustment unit 120 can additionally determine the other three points based on the determined point.

[0196] For example, if the positive electrode participation start point (pi') is determined first, the curve adjustment unit 120 can set the point on the adjusted first reference curve Rp' whose capacity value is larger than the capacity value of the positive electrode participation start point (pi') by the same range as the capacity of the battery curve M as the positive electrode participation termination point (pf'). Furthermore, the curve adjustment unit 120 can search for points on the adjusted second reference curve Rn' that are lower than the positive electrode participation start point (pi') by a first set voltage, and set the searched point as the negative electrode participation start point (ni'). Additionally, the curve adjustment unit 120 can set the point on the adjusted second reference curve Rn' whose capacity value is larger than the capacity value of the negative electrode participation start point (ni') by the same range as the capacity of the battery curve M as the negative electrode participation termination point (nf').

[0197] As another example, if the positive electrode participation termination point (pf') is determined first, the curve adjustment unit 120 can set a point on the adjusted first reference curve Rp' whose capacity value is smaller than the capacity value of the positive electrode participation termination point (pf') within the capacity range of the battery curve M as the positive electrode participation start point (pi'). Furthermore, the curve adjustment unit 120 can search for points on the adjusted second reference curve Rn' that are lower than the positive electrode participation termination point (pf') by a second set voltage, and set the searched point as the negative electrode participation termination point (nf'). Additionally, the curve adjustment unit 120 can set a point on the adjusted second reference curve Rn' whose capacity value is smaller than the capacity value of the negative electrode participation termination point (nf') within the capacity range of the battery curve M as the negative electrode participation start point (ni').

[0198] As another example, if the negative electrode participation start point (ni') is determined, the curve adjustment unit 120 can set the point on the adjusted second reference curve Rn' whose capacity value is greater than the capacity value of the negative electrode participation start point (ni') by a range equal to the capacity of the battery curve M as the negative electrode participation termination point (nf'). Furthermore, the curve adjustment unit 120 can search for points on the adjusted first reference curve Rp' that are higher than the negative electrode participation start point (ni') by a first set voltage, and set the searched point as the positive electrode participation start point (pi'). Additionally, the curve adjustment unit 120 can set the point on the adjusted first reference curve Rp' whose capacity value is greater than the capacity value of the positive electrode participation start point (pi') by a range equal to the capacity of the battery curve M as the positive electrode participation termination point (pf').

[0199] As another example, if the negative electrode participation termination point (nf') is determined, the curve adjustment unit 120 can set a point on the adjusted second reference curve Rn' whose capacity value is smaller than the capacity value of the negative electrode participation termination point (nf') within the capacity range of the battery curve M as the negative electrode participation start point (ni'). Furthermore, the curve adjustment unit 120 can search for a point on the adjusted first reference curve Rp' that is higher than the negative electrode participation termination point (nf') by a second set voltage, and set the searched point as the positive electrode participation termination point (pf'). Additionally, the curve adjustment unit 120 can set a point on the adjusted first reference curve Rp' whose capacity value is smaller than the capacity value of the positive electrode participation termination point (pf') within the capacity range of the battery curve M as the positive electrode participation start point (pi').

[0200] When the positive electrode participation start point (pi'), positive electrode participation end point (pf'), negative electrode participation start point (ni'), and negative electrode participation end point (nf') are determined based on the first scaling factor and the second scaling factor, the curve adjustment unit 120 can shift at least one of the adjusted first reference curve Rp' and the adjusted second reference curve Rn' to the left or right along the horizontal axis, so that the capacity value of the positive electrode participation start point (pi') matches the capacity value of the negative electrode participation start point (ni'), or so that the capacity value of the positive electrode participation end point (pf') matches the capacity value of the negative electrode participation end point (nf').

[0201] Figure 10 The adjusted second reference curve Rn'' shown is simply shifted to the right. Figure 9 The adjusted second reference curve Rn' is shown. Therefore, the capacity value at the positive electrode participation initiation point (pi') matches the capacity value at the negative electrode participation initiation point (ni''). In this respect, since the capacity difference between the positive electrode participation initiation point (pi') and the positive electrode participation termination point (pf') is the same as the capacity difference between the negative electrode participation initiation point (ni') and the negative electrode participation termination point (nf'), when the capacity value at the positive electrode participation initiation point (pi') matches the capacity value at the negative electrode participation initiation point (ni''), the capacity value at the positive electrode participation termination point (pf') also matches the capacity value at the negative electrode participation termination point (nf').

[0202] refer to Figure 10 The curve adjustment unit 120 can generate a comparison curve U by subtracting the portion of the curve between two points (ni'', nf'') of the adjusted first reference curve Rp' from the portion of the curve between two points (ni'', nf'') of the adjusted second reference curve Rn''.

[0203] The curve adjustment unit 120 can calculate the error (curve error) between the comparison curve U and the third reference curve R.

[0204] The curve adjustment unit 120 can map at least two of the adjusted first reference curve Rp', the adjusted second reference curve Rn'', the positive electrode participation start point (pi'), the positive electrode participation end point (pf'), the negative electrode participation start point (ni''), the negative electrode participation end point (nf''), the first scaling factor, the second scaling factor, the comparison curve U, and the curve error to each other, and record them in the storage unit 140.

[0205] As described above, the curve adjustment unit 120 can generate a comparison curve corresponding to each pair of first scaling factors and second scaling factors selected from the scaling value range. Since there are multiple pairs of first scaling factors and second scaling factors, it is obvious that multiple comparison curves will also be generated. The curve adjustment unit 120 can identify the minimum value among the curve errors of the multiple comparison curves, and then obtain the information mapped to the minimum curve error from the storage unit 140.

[0206] Figure 11 This diagram is used to explain the differences between the first and second batteries.

[0207] The first battery is a reference battery, and the second battery is a battery that has lost usable lithium. Specifically, the second battery is a battery that has lost usable lithium due to a drooping defect.

[0208] Here, "overhang" refers to a condition where the negative electrode area of ​​a battery is wider than its positive electrode area. In other words, an overhang defect is a defect where the negative electrode area is smaller than the positive electrode area. Overhang defects can occur due to manufacturing problems or battery damage. In particular, batteries with overhang defects are known to have more lithium metal deposited in the edge region of the negative electrode than in the central region.

[0209] For example, when using Raman spectroscopy to analyze a cell with overhang defects, I in the edge region D / I G The ratio is higher than that in the central region. D / I G Therefore, overhang defects may be one of the reasons for the loss of available lithium.

[0210] exist Figure 11 In the embodiments, the first characteristic value (pi) of the first battery in the BOL state BOL ) and the first characteristic value (pi) of the second cell in the BOL state. BOL () equals 6.7%.

[0211] The first characteristic value (pi) of the first cell in the MOL (Mid-Life) state MOLThe first characteristic value (pi) of the second battery in the MOL state is 6.9%. MOL The percentage is 7.8%. That is, the first characteristic value (pi) of the second cell exhibiting overhang defects is... MOL ) is greater than the first characteristic value (pi) of the reference cell MOL Here, the first characteristic value (pi) of the first battery in the MOL state. MOL This can be set as a first standard value. Therefore, the control unit 130 can diagnose the state of the battery based on the result of comparing the battery's first characteristic value with the preset first standard value.

[0212] Available lithium loss rate (L) of the first cell in MOL state Li The available lithium loss rate (L) of the second battery in the MOL state is 0.2%. Li The usable lithium loss rate (L) of the second cell exhibiting overhang defects is 1.4%. Li The available lithium loss rate is greater than that of the reference battery (L). Li Here, the available lithium loss rate (L) of the first cell in the MOL state is... Li This can be set as a second standard value. Therefore, the control unit 130 can diagnose the battery's condition based on the result of comparing the battery's available lithium loss rate with the preset second standard value.

[0213] On the other hand, the positive electrode capacity loss rate (L) of the first battery in the MOL state Q The positive electrode capacity loss rate (L) of the second battery in the MOL state is 6.8%. Q The percentage is 6.6%. In other words, the positive electrode capacity loss rate of the first and second batteries shows a difference within a certain level, so the degree of loss of positive electrode capacity of the second battery is normal.

[0214] Summarize Figure 11 Based on the first standard value (the first characteristic value of the first battery (pi) MOL )) and the first characteristic value (pi) of the second battery MOL Based on the first result of the comparison, the control unit 130 can diagnose the battery's state as a state of available lithium loss.

[0215] Furthermore, based on the second standard value (the available lithium loss rate of the first battery (L...)... Li The available lithium loss rate of the second battery (L) Li Based on the second result of the comparison, the control unit 130 can diagnose the battery's state as a state of available lithium loss.

[0216] Preferably, since the first result is the same as the second result, the control unit 130 can diagnose the state of the battery as a state of available lithium loss.

[0217] The battery diagnostic apparatus 100 according to this disclosure can be applied to a battery management system (BMS). That is, the BMS according to this disclosure may include the battery diagnostic apparatus 100 described above. In this configuration, at least some of the components of the battery diagnostic apparatus 100 can be implemented by supplementing or adding the functions of components included in a conventional BMS. For example, the curve acquisition unit 110, the curve adjustment unit 120, and the control unit 130 of the battery diagnostic apparatus 100 can be implemented as components of the BMS.

[0218] Furthermore, the battery diagnostic device 100 according to this disclosure can be disposed in a battery pack. That is, the battery pack according to this disclosure may include the aforementioned battery diagnostic device 100 and at least one battery cell. In addition, the battery pack may also include electrical components (relays, fuses, etc.) and a housing.

[0219] Figure 12 This is a schematic diagram illustrating a battery pack 10 including a device 100 for diagnosing batteries according to another embodiment of the present disclosure.

[0220] The positive terminal of battery 11 can be connected to the positive terminal P+ of battery pack 10, and the negative terminal of battery 11 can be connected to the negative terminal P- of battery pack 10.

[0221] The measurement unit 12 can be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measurement unit 12 can be connected to the positive terminal of the battery 11 via the first sensing line SL1 and to the negative terminal of the battery 11 via the second sensing line SL2. The measurement unit 12 can measure the voltage of the battery 11 based on the voltage measured at each of the first sensing line SL1 and the second sensing line SL2.

[0222] Furthermore, the measurement unit 12 can be connected to the current measurement unit A via the third sensing line SL3. For example, the current measurement unit A can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 11. The measurement unit 12 can measure the charging current of the battery 11 via the third sensing line SL3 to calculate the amount of charge. Additionally, the measurement unit 12 can measure the discharging current of the battery 11 via the third sensing line SL3 to calculate the amount of discharge.

[0223] An external device can be connected to the positive terminal P+ and the negative terminal P- of the battery pack 10. For example, the external device can be a charging device or a load. In addition, the positive terminal of the battery 11, the positive terminal P+ of the battery pack 10, the external device, the negative terminal P- of the battery pack 10, and the negative terminal of the battery 11 can be electrically connected.

[0224] Figure 13 The figure schematically illustrates a vehicle 1300 according to another embodiment of the present disclosure.

[0225] refer to Figure 13 According to one embodiment of this disclosure, a battery pack 1310 can be included in a vehicle 1300, such as an electric vehicle (EV) or a hybrid vehicle (HV). Furthermore, the battery pack 1310 can supply power to a motor via an inverter disposed in the vehicle 1300 to drive the vehicle 1300. Here, the battery pack 1310 may include a device 100 for diagnosing the battery. That is, the vehicle 1300 may include a device 100 for diagnosing the battery. In this case, the device 100 for diagnosing the battery may be an on-board device included in the vehicle 1300.

[0226] Figure 14 This is a schematic diagram illustrating a method for diagnosing a battery according to yet another embodiment of the present disclosure.

[0227] refer to Figure 14 The method for diagnosing a battery may include a curve acquisition step (S100), a curve adjustment step (S200), and a diagnosis step (S300).

[0228] Preferably, each step of the method for diagnosing the battery can be performed by the device 100 for diagnosing the battery. In the following text, for ease of explanation, content repeated above will be omitted or briefly described.

[0229] The curve acquisition step (S100) is a step of obtaining a battery curve that represents the correspondence between the battery's voltage and capacity, and can be performed by the curve acquisition unit 110.

[0230] For example, the curve acquisition unit 110 can receive the battery curve directly from the outside. That is, the curve acquisition unit 110 can obtain the battery curve by connecting to the outside via a wired and / or wireless connection and receiving the battery curve.

[0231] As another example, the curve acquisition unit 110 can receive battery information regarding the battery's voltage and capacity. Then, the curve acquisition unit 110 can generate a battery curve based on the received battery information. That is, the curve acquisition unit 110 can obtain a battery curve by directly generating a battery curve based on the battery information.

[0232] The curve adjustment step (S200) is a step of adjusting the preset first reference curve and second reference curve to correspond to the battery curve and generating the first curve according to the adjustment result, and can be executed by the curve adjustment unit 120.

[0233] For example, the curve adjustment unit 120 can generate multiple comparison curves by shifting or scaling the capacity of the first and second reference curves, and specify the comparison curve with the smallest error to the battery curve among the multiple comparison curves. Then, the curve adjustment unit 120 can determine the adjusted first reference curve and the adjusted second reference curve corresponding to the specified comparison curve as the first curve and the second curve, respectively.

[0234] The diagnostic step (S300) is a step of diagnosing the state of the battery based on the first characteristic value of the first characteristic point included in the first curve, and can be executed by the control unit 130.

[0235] In one embodiment, the control unit 130 may diagnose the state of the battery based on the result of comparing a first characteristic value with a first standard value.

[0236] In another embodiment, the control unit 130 may calculate the available lithium loss rate of the battery based on a first feature value, and diagnose the battery status based on the calculated available lithium loss rate.

[0237] In another embodiment, the control unit 130 can diagnose the state of the battery by considering both the result of comparing a first characteristic value with a first standard value and the result of comparing the battery's available lithium loss rate with a second standard value.

[0238] The embodiments of this disclosure described above can be implemented not only by apparatus and methods, but also by a program that implements functions corresponding to the configuration of the embodiments of this disclosure, or a recording medium on which the program is stored. Based on the above description of the embodiments, those skilled in the art can readily implement the program or recording medium.

[0239] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various changes and modifications within the scope of this disclosure will become apparent to those skilled in the art based on this detailed description.

[0240] Furthermore, those skilled in the art can make various substitutions, modifications and changes to the present disclosure described above without departing from the technical aspects of the present disclosure, and the present disclosure is not limited to the above embodiments and drawings, and each embodiment can be selectively combined in part or in whole to allow for various modifications.

[0241] (Explanation of the labels in the attached diagram)

[0242] 10: Battery Pack

[0243] 11: Battery

[0244] 12: Measurement Unit

[0245] 100: Devices for diagnosing batteries

[0246] 110: Curve Acquisition Unit

[0247] 120: Curve Adjustment Unit

[0248] 130: Control Unit

[0249] 140: Storage unit

[0250] 1300: Vehicles

[0251] 1310: Battery pack

Claims

1.An apparatus for diagnosing a battery, comprising: a curve obtaining unit configured to obtain a battery curve representing a correspondence between a voltage and a capacity of a battery; a curve adjusting unit configured to adjust a preset first reference curve and a preset second reference curve to correspond to the battery curve, and generate a first curve according to an adjustment result; and a control unit configured to diagnose a state of the battery based on a first characteristic value of a first characteristic point included in the first curve. 2.The apparatus for diagnosing a battery according to claim 1, the control unit is configured to diagnose the state of the battery as a normal state or a usable lithium loss state. wherein, 3.The apparatus for diagnosing a battery according to claim 2, the control unit is configured to: wherein diagnose the state of the battery as the usable lithium loss state when the first characteristic value exceeds a preset first standard value, and diagnose the state of the battery as the normal state when the first characteristic value is less than or equal to the first standard value. 4.The apparatus for diagnosing a battery according to claim 2, the control unit is configured to calculate a usable lithium loss rate based on a preset first reference value, a preset second reference value, and the first characteristic value, compare the calculated usable lithium loss rate with a preset second standard value, and diagnose the state of the battery based on a comparison result. wherein 5.The apparatus for diagnosing a battery according to claim 4, the control unit is configured to: wherein diagnose the state of the battery as the usable lithium loss state when the usable lithium loss rate exceeds the second standard value, and diagnose the state of the battery as the normal state when the usable lithium loss rate is less than or equal to the second standard value. 6.The apparatus for diagnosing a battery according to claim 4, the first reference value is preset as an SOC of a first reference point included in the first reference curve, and wherein wherein the second reference value is preset as an SOC of a second reference point included in the first reference curve. 7.The apparatus for diagnosing a battery according to claim 1, the first characteristic value is an SOC of the first characteristic point included in the first curve. wherein, 8.A battery pack comprising the apparatus for diagnosing a battery according to any one of claims 1 to 7. 9.A vehicle comprising the apparatus for diagnosing a battery according to any one of claims 1 to 7. 10.A method for diagnosing a battery, comprising: a curve obtaining step of obtaining a battery curve representing a correspondence between a voltage and a capacity of a battery; a curve adjusting step of adjusting a preset first reference curve and a preset second reference curve to correspond to the battery curve, and generating a first curve according to an adjustment result; and a battery diagnosing step of diagnosing a state of the battery based on a first characteristic value of a first characteristic point included in the first curve. ​ ​

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