Battery diagnostic device and method

Abstract

A battery diagnostic device according to an embodiment of the present invention includes: a data acquisition unit configured to measure battery information including a voltage and a current of the battery during a charging cycle of the battery; and a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to determine a type of deterioration of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2022-0143796, filed on November 1, 2022, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[0002] The present invention relates to a battery diagnostic device and method, and more particularly to a battery diagnostic device and method capable of diagnosing the state of a battery in a non-destructive manner. [Background technology]

[0003] In recent years, as demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and the development of electric vehicles, energy storage batteries, robots, and artificial satellites has gained momentum, active research is being conducted into high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are attracting attention due to their advantages of being able to be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, as well as their extremely low self-discharge rate and high energy density.

[0005] These batteries deteriorate with repeated charging and discharging. For example, gas generation can reduce the electron transfer ability within the electrodes, leading to imbalance in anode deterioration. Furthermore, the amount of gas generated by the battery can lead to fire, so if the battery's condition is not diagnosed promptly, an unexpected accident may occur. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery diagnostic apparatus and method that can diagnose the state of a battery in a non-destructive manner through profile analysis.

[0007] Other objects and advantages of the present invention will become apparent from the following description and the embodiments of the present invention, and can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0008] According to one aspect of the present invention, a battery diagnostic device includes: a data acquisition unit configured to measure battery information including a voltage and a current of the battery during a charging cycle of the battery; and a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to determine a type of deterioration of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0009] The control unit may be configured to divide the total charging capacity in the charging cycle into a constant current charging capacity and a constant voltage charging capacity, and to calculate the constant current charging capacity ratio and the constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity.

[0010] The control unit may be configured to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio when a total charge capacity of the battery decreases during a charge cycle of the battery.

[0011] The control unit may be configured to diagnose the type of deterioration of the battery as capacity deterioration or combined deterioration based on an increase or decrease in the constant current charging capacity ratio and the constant voltage charging capacity ratio.

[0012] The control unit may be configured to compare a rate of change of the constant current charging capacity ratio with a preset first rate of change, and to compare a rate of change of the constant voltage charging capacity ratio with a preset second rate of change.

[0013] The control unit may be configured to diagnose the type of deterioration of the battery as the combined deterioration if the rate of change of the constant current charging capacity ratio is less than the first rate of change and the rate of change of the constant voltage charging capacity ratio is greater than or equal to the second rate of change.

[0014] The control unit may be configured to diagnose the type of deterioration of the battery as capacity deterioration if the rate of change of the constant current charging capacity ratio is equal to or greater than the first rate of change and the rate of change of the constant voltage charging capacity ratio is less than the second rate of change.

[0015] The control unit may be configured to change a charge cutoff condition of the battery if the type of deterioration of the battery is diagnosed as the combined deterioration.

[0016] The control unit may be configured to reduce a constant current charge cutoff voltage among the charge cutoff conditions if the type of deterioration of the battery is diagnosed as the combined deterioration.

[0017] The control unit may be configured to increase a constant voltage charge cutoff current among the charge cutoff conditions if the type of deterioration of the battery is diagnosed as the combined deterioration.

[0018] The control unit may be configured to reduce a constant voltage charge cutoff time among the charge cutoff conditions if the type of deterioration of the battery is diagnosed as the combined deterioration.

[0019] A battery pack according to another aspect of the present invention includes the battery diagnostic device according to an aspect of the present invention.

[0020] According to yet another aspect of the present invention, a battery diagnosis method includes: a battery information acquiring step of acquiring battery information including a voltage and a current of the battery during a charging cycle of the battery; a charging capacity ratio calculating step of calculating a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information; and a battery deterioration type determining step of determining a type of deterioration of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio. [Effects of the Invention]

[0021] According to one aspect of the present invention, the state of a battery can be diagnosed in a non-destructive manner through profile analysis. In particular, the type of battery deterioration can be specifically diagnosed using the constant current charge capacity ratio and the constant voltage charge capacity ratio of the battery.

[0022] The effects of the present invention are not limited to the effects described above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0023] The following drawings attached to this specification, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram illustrating a battery diagnostic device according to an embodiment of the present invention; [Figure 2] FIG. 10 is a diagram illustrating a total charge capacity profile according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram illustrating a constant current charging capacity rate profile according to an embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram illustrating a constant voltage charge capacity rate profile according to an embodiment of the present invention. [Figure 5]10A and 10B are diagrams illustrating a constant current charging capacity ratio profile and a constant voltage charging capacity ratio profile according to another embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating a constant current charging capacity ratio profile and a constant voltage charging capacity ratio profile according to still another embodiment of the present invention. [Figure 7] FIG. 10 is a diagram schematically illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 8] 10 is a diagram illustrating a battery diagnostic method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The terms and words used in this specification and claims should not be interpreted limited to their ordinary and dictionary meanings, but should be interpreted in a meaning and concept that corresponds to the technical idea of the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to explain the invention in the best way.

[0026] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0027] Furthermore, in the description of the present invention, if it is determined that a detailed description of related known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0028] Terms including ordinal numbers such as "first," "second," etc. are used to distinguish one of various components from other components, and do not limit the components.

[0029] Throughout this specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0030] Furthermore, throughout this specification, when a part is referred to as being "connected" to another part, this includes not only a "direct connection" but also an "indirect connection" via other elements.

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0032] FIG. 1 is a diagram illustrating a battery diagnostic device 100 according to an embodiment of the present invention.

[0033] Referring to FIG. 1, a battery diagnostic device 100 according to an embodiment of the present invention includes a data acquisition unit 110 and a control unit 120.

[0034] The data acquisition unit 110 may acquire battery information including the voltage and current of the battery during a charging cycle. For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery measured during the charging process of the battery.

[0035] Here, the battery charging process can include constant current (CC) charging and constant voltage (CV) charging. Note that for the sake of convenience, the terms constant current charging and CC charging, and constant voltage charging and CV charging will be used interchangeably below.

[0036] Here, a battery refers to a single independent cell that has a negative terminal and a positive terminal and can be physically separated. As an example, a single lithium ion cell or lithium polymer cell may be considered a battery. A battery may also refer to a battery module in which multiple cells are connected in series and / or parallel. A battery may also refer to a battery pack in which multiple battery modules are connected in series and / or parallel. For convenience of explanation, a battery will be described below as referring to a single cell.

[0037] According to the embodiment, the data acquisition unit 110 may acquire battery information measured through a voltage sensing line connected to the positive and negative electrodes of the battery. The data acquisition unit 110 may also be connected to a current sensor that measures the current of the battery. The data acquisition unit 110 may also acquire battery information from the current sensor through the current sensing line.

[0038] The data acquisition unit 110 may acquire battery information including the voltage and current of the battery in real time during the charging cycle of the battery.

[0039] According to an embodiment, the data acquisition unit 110 may be configured to be able to communicate with an external device, and may receive battery information from an external device via communication.

[0040] The control unit 120 and the data acquisition unit 110 may be connected to each other via a wired and / or wireless connection so that they can communicate with each other. The control unit 120 may receive battery information from the data acquisition unit 110 via a wired line and / or a wireless communication network.

[0041] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during a charging cycle based on the battery information acquired from the data acquisition unit 110 .

[0042] A charge cycle may refer to charging a battery from the lower limit to the upper limit of a preset charge voltage range while maintaining a constant battery temperature, and then interrupting the charging. A charge cycle may be included in a charge / discharge cycle together with a discharge cycle. A discharge cycle may refer to stabilizing the battery for a predetermined time after completing a charge cycle, then discharging the battery from the upper limit to the lower limit of a preset discharge voltage range while maintaining the battery temperature in the same manner as in the charge cycle, and then interrupting the discharging. The charge voltage range and the discharge voltage range may be the same or different. However, when performing multiple charge / discharge cycles, it is preferable that the charge voltage ranges of the charge cycles are the same, and that the discharge voltage ranges of the discharge cycles are also the same.

[0043] As another example, a charge cycle refers to charging a battery from the lower limit to the upper limit of a predetermined charge voltage range while maintaining a constant battery temperature, and then interrupting the charge. A discharge cycle refers to starting discharge from the upper limit of a predetermined discharge voltage range, integrating the discharge current, and interrupting the discharge when the integrated current value reaches a predetermined discharge capacity. When performing multiple charge / discharge cycles, it is preferable that the charge voltage ranges of the charge cycles are the same and the discharge capacities of the discharge cycles are the same.

[0044] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle.

[0045] Specifically, the control unit 120 may be configured to divide the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity, and may be configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity.

[0046] Here, the constant current charging capacity may refer to the capacity charged by constant current charging, and the constant voltage charging capacity may refer to the capacity charged by constant voltage charging.

[0047] For example, the control unit 120 may calculate the constant current charging capacity ratio by calculating the ratio of the constant current charging capacity to the total charging capacity in the charging cycle. Also, the control unit 120 may calculate the constant voltage charging capacity ratio by calculating the ratio of the constant voltage charging capacity to the total charging capacity.

[0048] According to an embodiment, the control unit 120 may receive information about the total charge capacity, the constant current charge capacity, and the constant voltage charge capacity measured during the CC-CV charging process of the battery. In this case, the control unit 120 may calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the received information.

[0049] The control unit 120 may determine the type of battery deterioration based on the constant current charging capacity ratio and the constant voltage charging capacity ratio. The type of battery deterioration may include combined deterioration or capacity deterioration. Capacity deterioration may refer to basic deterioration that occurs with battery use. Since capacity deterioration is basic deterioration that occurs with battery use, it corresponds to a normal mode in which the battery can be used as expected by deteriorating at a normal rate, and additional control of charging conditions is not required.

[0050] The composite degradation may refer to degradation in which resistance degradation occurs in addition to capacity degradation. In the case of composite degradation, since it corresponds to an accelerated degradation mode, active control of charging conditions is required.

[0051] The battery diagnostic device 100 according to an embodiment of the present invention can specifically diagnose the type of deterioration of the battery by comparing the constant current charging capacity ratio and the constant voltage charging capacity ratio of the battery.

[0052] The battery diagnostic device 100 according to an embodiment of the present invention can specifically diagnose the type of battery deterioration, and actively control the charging conditions in the case of complex deterioration, which is an accelerated deterioration mode.

[0053] Meanwhile, the data acquisition unit 110 and the control unit 120 included in the battery diagnostic device 100 may selectively include a processor, an application-specific integrated circuit (ASIC), other chipsets, logic circuits, registers, a communication modem, a data processing device, etc., known in the art, to execute various control logics performed in the present invention. Furthermore, when the control logic is embodied as software, the data acquisition unit 110 and the control unit 120 may be embodied as a collection of program modules. In this case, the program modules may be stored in a memory and executed by the data acquisition unit 110 and the control unit 120. The memory may be provided inside or outside the data acquisition unit 110 and the control unit 120, respectively, and may be connected to the data acquisition unit 110 and the control unit 120 by various well-known means.

[0054] The battery diagnostic device 100 may further include a recording unit 130. The recording unit 130 may store data and programs necessary for each component of the battery diagnostic device 100 to operate and function, or data generated during the operation and function. The recording unit 130 may be any known information recording means capable of recording, erasing, updating, and reading data. For example, the information recording means may include RAM, flash memory, ROM, EEPROM, registers, etc. The recording unit 130 may also store program code defining processes executable by the control unit 120.

[0055] The control unit 120 will now be described in detail. Figure 2 is a diagram illustrating a total charge capacity profile according to an embodiment of the present invention. Figure 2 shows an X-Y two-dimensional graph in which X is set to the charge cycle and Y is set to the total charge capacity.

[0056] 2, it can be seen that the total charge capacity decreases linearly as the number of charge cycles increases. Generally, the more a battery deteriorates (the more charge cycles there are), the more the total charge capacity of the battery may decrease. Therefore, the control unit 120 cannot diagnose the type of battery deterioration based on the decrease in total capacity using only the profile of FIG. 2.

[0057] In other words, it is not possible to determine whether the battery is in a capacity degradation state where only capacity degradation has occurred, or a complex degradation state where resistance degradation has also occurred, and therefore it is not possible to determine whether the battery is in an accelerated degradation mode.

[0058] In one embodiment, the control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio when the total charging capacity of the battery decreases during a charging cycle of the battery.

[0059] Specifically, the control unit 120 may be configured to compare the total charge capacity of the immediately preceding charge cycle with the total charge capacity of the current charge cycle and determine whether to calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the comparison result. For example, if the total charge capacity of the current charge cycle is lower than the total charge capacity of the immediately preceding charge cycle, the control unit 120 may calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio for the current charge cycle.

[0060] According to an embodiment of the present invention, the control unit 120 may classify the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity. For example, the control unit 120 may classify the capacity charged by constant current charging of the total charging capacity as the constant current charging capacity, and may classify the capacity charged by constant voltage charging of the total charging capacity as the constant voltage charging capacity.

[0061] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity. For example, the control unit 120 may calculate the constant current charging ratio by comparing the constant current charging capacity with the total charging capacity. This will be described below with reference to FIG. 3.

[0062] 3 is a schematic diagram illustrating a constant current charge capacity ratio profile according to an embodiment of the present invention, showing an X-Y two-dimensional graph in which X is set to the charge cycle and Y is set to the constant current charge capacity ratio.

[0063] 3, it can be seen that the constant current charging capacity ratio decreases linearly as the number of cycles increases, and then decreases sharply at a specific point A. In addition, the control unit 120 can diagnose the type of battery degradation based on the change in the constant current charging capacity ratio.

[0064] As described above, types of battery degradation may include combined degradation and capacity degradation. Capacity degradation may refer to basic degradation that occurs with battery use. Combined degradation may refer to degradation in which resistance degradation occurs in addition to capacity degradation. Combined degradation corresponds to an accelerated degradation mode, so active control of charging conditions is required.

[0065] The control unit 120 may diagnose the type of battery degradation as combined degradation or capacity degradation based on the increase or decrease in the constant current charging capacity ratio. For example, referring to FIG. 3, the control unit 120 may diagnose that the type of degradation changes from capacity degradation to combined degradation at a specific point A.

[0066] That is, according to one embodiment of the present invention, the control unit 120 can diagnose that the type of deterioration changes at a specific point A by using the constant current charging capacity ratio. In addition, the control unit 120 can diagnose that the type of deterioration of the battery changes at the specific point A from capacity deterioration, in which only capacity deterioration has occurred, to compound deterioration, in which resistance deterioration has also occurred, and thus can determine that the battery has entered an accelerated deterioration mode at the specific point A.

[0067] As another example, the control unit 120 may compare the constant voltage charging capacity of the total charging capacity with the total charging capacity to calculate the constant voltage charging ratio, which will be described below with reference to FIG.

[0068] 4 is a schematic diagram illustrating a constant voltage charge capacity ratio profile according to an embodiment of the present invention, showing an X-Y two-dimensional graph in which X is set to the charge cycle and Y is set to the constant voltage charge capacity ratio.

[0069] 4, it can be seen that the constant voltage charge capacity ratio increases linearly as the number of cycles increases, and then increases sharply at a specific point B. In addition, the control unit 120 can diagnose the type of battery degradation based on the change in the constant voltage charge capacity ratio.

[0070] Preferably, the specific point A in Figure 3 and the specific point B in Figure 4 may represent the same charging cycle. For example, the specific point A in Figure 3 and the specific point B in Figure 4 may represent 400 cycles.

[0071] The control unit 120 may diagnose that the type of deterioration changes at a specific point B using the constant voltage charging capacity ratio. The type of battery deterioration may include combined deterioration and capacity deterioration. The control unit 120 may diagnose the type of battery deterioration as combined deterioration or capacity deterioration based on an increase or decrease in the constant voltage charging capacity ratio. For example, referring to FIG. 4, the control unit 120 may diagnose that the type of deterioration changes from capacity deterioration to combined deterioration at point B where the slope of the constant voltage charging capacity ratio changes abruptly.

[0072] That is, according to one embodiment of the present invention, the control unit 120 can diagnose that the type of deterioration is changed at a specific point B by using the constant voltage charge capacity ratio.

[0073] In addition, the control unit 120 can diagnose that the type of battery deterioration changes from capacity deterioration, in which only capacity deterioration has occurred, to compound deterioration, in which resistance deterioration has also occurred, at a specific point B, and therefore can determine that the battery has entered an accelerated deterioration mode at a specific point B.

[0074] According to an embodiment of the present invention, the control unit 120 may compare the rate of change of the charge capacity ratio with a preset rate of change. For example, the control unit 120 may compare the rate of change of the constant current charge capacity ratio with a preset first rate of change. Also, the control unit 120 may compare the rate of change of the constant voltage charge capacity ratio with a preset second rate of change. This will be described in detail with reference to FIGS. 5 and 6.

[0075] 5 is a diagram illustrating a constant current charge capacity ratio profile and a constant voltage charge capacity ratio profile according to another embodiment of the present invention, in which X is the charge cycle and Y is the constant current charge capacity ratio, and an X-Y two-dimensional graph illustrating a preset first change rate t1 is shown, and an X-Y two-dimensional graph illustrating a preset second change rate t2 is shown, in which X is the charge cycle and Y is the constant voltage charge capacity ratio.

[0076] The control unit 120 may compare the rate of change of the constant current charging capacity ratio with a preset first rate of change t1, and may compare the rate of change of the constant voltage charging capacity ratio with a preset second rate of change t2.

[0077] For example, the control unit 120 may compare the constant current charging capacity change rate with a preset first change rate t1 using a profile such as that shown in Fig. 5. Alternatively, the control unit 120 may compare the constant voltage charging capacity change rate with a preset second change rate t2.

[0078] The control unit 120 can diagnose the type of deterioration based on the result of comparing the rates of change.

[0079] In one embodiment, the control unit 120 may diagnose the type of battery deterioration as combined deterioration if the rate of change of the constant current charging capacity ratio is less than the first rate of change t1 and the rate of change of the constant voltage charging capacity ratio is greater than or equal to the second rate of change t2.

[0080] For example, referring to FIG. 5, if the constant current charging capacity ratio falls within section C where the rate of change of the constant voltage charging capacity ratio is less than the first rate of change t1 and the rate of change of the constant voltage charging capacity ratio is greater than or equal to the second rate of change t2, the control unit 120 may diagnose the type of battery deterioration as combined deterioration.

[0081] Conversely, referring to FIG. 6, the control unit 120 may diagnose the type of battery deterioration as capacity deterioration in section D where the constant current charging capacity ratio is equal to or greater than the first change rate t1 and the change rate of the constant voltage charging capacity ratio is less than the second change rate t2.

[0082] If the type of battery deterioration is diagnosed as combined deterioration, the control unit 120 may change the charge cutoff condition of the battery. Here, the charge cutoff condition may be preset to a condition that allows CC-CV charging of the battery to be terminated.

[0083] Specifically, the control unit 120 may be configured to change the charge cutoff condition so that battery charging (CC-CV charging) can be completed earlier than before. That is, by changing the charge cutoff condition, battery use at high voltages can be reduced, thereby preventing or mitigating battery degradation.

[0084] The charge cutoff conditions changed by the control unit 120 will be described below.

[0085] The charge cutoff conditions may include conditions regarding a cutoff voltage, a cutoff current, a cutoff time, etc. Preferably, if the type of battery deterioration is diagnosed as complex deterioration, the control unit 120 may change at least one of the charge cutoff conditions so as to terminate charging of the battery early.

[0086] If the type of battery deterioration is diagnosed as combined deterioration, the control unit 120 may control CC-CV charging by changing the charge cutoff conditions to reduce the time the battery remains at a high potential.

[0087] The cutoff voltage may refer to the voltage at which CC charging ends. CC charging is performed until the battery voltage reaches a set cutoff voltage, and CV charging may begin once the battery voltage reaches the cutoff voltage. Therefore, if the cutoff voltage decreases, battery charging may end earlier than before. For example, the control unit 120 may change and set a preset cutoff voltage for the battery based on the diagnosis result to extend the battery's lifespan. Here, setting a cutoff voltage means setting an upper limit charging voltage for the battery. For example, if the cutoff voltage decreases based on the diagnosis result, the upper limit charging voltage for the battery may be lowered. In this case, the usable voltage range of the battery is reduced, limiting the use of the battery at high voltages, thereby preventing or mitigating battery degradation.

[0088] The cutoff current may refer to the current at which CV charging ends. During CV charging of a battery, the battery voltage may be maintained constant corresponding to the cutoff voltage, and the charging current may decrease. Furthermore, when the charging current reaches the cutoff current, charging of the battery may end. Therefore, if the cutoff current increases, charging of the battery may end earlier than before. For example, if the type of battery degradation is diagnosed as combined degradation, the control unit 120 may increase the charging cutoff current. Increasing the CV charging cutoff current of the battery charging cycle may reduce the time the battery remains at a high potential.

[0089] The cutoff time may refer to the time required for CV charging, so if the cutoff time is reduced, the battery charging may be terminated sooner than before.

[0090] According to an embodiment, the control unit 120 may change at least one of the cutoff voltage, the cutoff current, and the cutoff time to effectively reduce the time that the battery, whose degradation type has been diagnosed as complex degradation, remains at a high potential. Preferably, the control unit 120 may change two or more of the cutoff voltage, the cutoff current, and the cutoff time to further reduce the time that the battery remains at a high potential.

[0091] Conversely, if the rate of change of the constant current charging capacity ratio is equal to or greater than the first rate of change and the rate of change of the constant voltage charging capacity ratio is less than the second rate of change, the control unit 120 may diagnose the type of battery deterioration as capacity deterioration.

[0092] 6 is a diagram illustrating a constant current charge capacity ratio profile and a constant voltage charge capacity ratio profile according to another embodiment of the present invention, in which X represents the charge cycle and Y represents the constant current charge capacity ratio, and an X-Y two-dimensional graph showing a preset first change rate is shown, and in which X represents the charge cycle and Y represents the constant voltage charge capacity ratio, and an X-Y two-dimensional graph showing a preset second change rate is shown.

[0093] For example, referring to FIG. 6, if the rate of change of the constant current charging capacity ratio falls within section D where the rate of change of the constant voltage charging capacity ratio is equal to or greater than the first rate of change and is less than the second rate of change, the control unit 120 may diagnose the type of battery deterioration as capacity deterioration.

[0094] That is, if the total charging capacity decreases but the rate of change of the constant current charging capacity ratio is similar to the first rate of change and the rate of change of the constant voltage charging capacity ratio maintains a level similar to the second rate of change, the control unit 120 may diagnose the type of deterioration as capacity deterioration.

[0095] If the type of battery degradation is diagnosed as capacity degradation, the control unit 120 may control CC-CV charging of the battery according to a preset charge cutoff condition. That is, unlike when the type of battery degradation is diagnosed as combined degradation, if the type of battery degradation is diagnosed as capacity degradation, the charge cutoff condition for early termination of battery charging may not be changed.

[0096] In other words, the battery diagnostic device according to an embodiment of the present invention has an advantage in that it can set charging conditions to correspond to the current state of the battery by maintaining or changing the charging cutoff conditions according to the state of the battery being diagnosed. In this way, it is possible to prevent battery deterioration based on the charging conditions set for each charging cycle, thereby increasing the expected lifespan of the battery.

[0097] The battery diagnostic device 100 according to the present invention may be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the above-described battery diagnostic device 100. In this configuration, at least some of the components of the battery diagnostic device 100 may be implemented by complementing or adding functions of components included in a conventional BMS. For example, the data acquisition unit 110, the control unit 120, and the recording unit 130 of the battery diagnostic device 100 may be implemented as components of the BMS.

[0098] FIG. 7 is a diagram schematically illustrating an exemplary configuration of a battery pack 1 according to another embodiment of the present invention.

[0099] The battery diagnostic device 100 according to the present invention may be provided in a battery pack 1. That is, the battery pack 1 according to the present invention may include the above-described battery diagnostic device 100, a measuring unit 200, and one or more batteries B. The battery pack 1 may further include electrical components (relays, fuses, etc.), a case, etc.

[0100] The positive terminal of battery B may be connected to the positive terminal P+ of battery pack 1, and the negative terminal of battery B may be connected to the negative terminal P- of battery pack 1.

[0101] The measuring unit 200 may be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measuring unit 200 may be connected to the positive terminal of battery B via the first sensing line SL1 and to the negative terminal of battery B via the second sensing line SL2. The measuring unit 200 may measure the voltage of battery B based on the voltages measured on the first sensing line SL1 and the second sensing line SL2.

[0102] The measuring unit 200 may also be connected to a current measuring unit A through a third sensing line SL3. For example, the current measuring unit A may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of battery B. The measuring unit 200 may measure the charging current of battery B through the third sensing line SL3 to calculate the charged amount. The measuring unit 200 may also measure the discharging current of battery B through the third sensing line SL3 to calculate the discharged amount.

[0103] The charging / discharging unit 300 may be a charging device or a load connectable to the battery pack 1. Specifically, one end of the charging / discharging unit 300 may be connected to the positive terminal P+ of the battery pack 1, and the other end may be connected to the negative terminal P- of the battery pack 1. Therefore, the positive terminal of battery B, the positive terminal P+ of battery pack 1, the charging / discharging unit 300, the negative terminal P- of battery pack 1, and the negative terminal of battery B may be electrically connected.

[0104] FIG. 8 is a diagram illustrating a battery diagnostic method according to another embodiment of the present invention.

[0105] Preferably, each step of the battery diagnostic method can be performed by the battery diagnostic device 100. In the following, the contents overlapping with the above description will be omitted or will be briefly described.

[0106] The battery information acquisition step S110 is a step of acquiring battery information including the voltage and current of the battery during a charging cycle of the battery, and may be performed by the data acquisition unit 110.

[0107] For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery during a charging cycle, for example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery measured during a CC-CV charging process of the battery.

[0108] For example, the data acquisition unit 110 may acquire battery information including the voltage and current of the battery in real time during the charging cycle of the battery.

[0109] The charge capacity ratio calculation step S120 is a step of calculating a constant current charge capacity ratio and a constant voltage charge capacity ratio during a charge cycle based on battery information, and may be performed by the control unit 120.

[0110] Specifically, the control unit 120 may be configured to divide the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity, and may be configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity.

[0111] Here, the constant current charging capacity may refer to the capacity charged by constant current charging, and the constant voltage charging capacity may refer to the capacity charged by constant voltage charging.

[0112] For example, the control unit 120 may calculate the constant current charging capacity ratio by calculating the ratio of the constant current charging capacity to the total charging capacity in the charging cycle. Also, the control unit 120 may calculate the constant voltage charging capacity ratio by calculating the ratio of the constant voltage charging capacity to the total charging capacity.

[0113] According to an embodiment, the control unit 120 may receive information about the total charge capacity, the constant current charge capacity, and the constant voltage charge capacity measured during the CC-CV charging process of the battery. In this case, the control unit 120 may calculate a constant current charge capacity ratio and a constant voltage charge capacity ratio based on the received information.

[0114] In one embodiment, the control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio when the total charging capacity of the battery decreases during a charging cycle of the battery.

[0115] According to an embodiment of the present invention, the control unit 120 may classify the total charging capacity in a charging cycle into a constant current charging capacity and a constant voltage charging capacity. For example, the control unit 120 may classify the capacity charged by constant current charging of the total charging capacity as the constant current charging capacity, and may classify the capacity charged by constant voltage charging of the total charging capacity as the constant voltage charging capacity.

[0116] The control unit 120 may calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio based on the divided constant current charging capacity and constant voltage charging capacity. For example, the control unit 120 may calculate the constant current charging ratio by calculating the ratio of the constant current charging capacity to the total charging capacity. The control unit 120 may calculate the constant voltage charging ratio by calculating the ratio of the constant voltage charging capacity to the total charging capacity.

[0117] The battery deterioration type determining step S130 is a step of determining the type of battery deterioration based on the constant current charging capacity ratio and the constant voltage charging capacity ratio, and may be performed by the control unit 120.

[0118] The control unit 120 may determine the type of battery deterioration based on the constant current charging capacity ratio and the constant voltage charging capacity ratio. The type of battery deterioration may include combined deterioration or capacity deterioration.

[0119] For example, if the rate of change of the constant current charging capacity ratio is less than the first rate of change and the rate of change of the constant voltage charging capacity ratio is equal to or greater than the second rate of change, the control unit 120 may diagnose the type of battery deterioration as complex deterioration.

[0120] As another example, the control unit 120 may diagnose the type of battery deterioration as capacity deterioration if the rate of change of the constant current charging capacity ratio is equal to or greater than the first rate of change and the rate of change of the constant voltage charging capacity ratio is less than the second rate of change.

[0121] Meanwhile, if the type of battery degradation is diagnosed as combined degradation, the control unit 120 may change the battery charge cutoff condition so that the battery charging is completed more quickly. By changing the charge cutoff condition, the time the battery remains at a high potential during charging may be reduced.

[0122] The above-described embodiments of the present invention may be realized not only by an apparatus and a method, but also by a program that realizes functions corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such realization can be easily realized by a person skilled in the art from the description of the above-described embodiments.

[0123] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims.

[0124] Furthermore, the present invention described above can be variously replaced, modified, and changed by a person having ordinary knowledge in the technical field to which the present invention belongs, within the scope that does not deviate from the technical concept of the present invention, and is not limited to the above-described embodiments and the accompanying drawings, but can be configured by selectively combining all or part of each embodiment to enable various modifications. [Explanation of symbols]

[0125] 1: Battery pack 100: Battery diagnostic device 110: Data acquisition unit 120: Control unit 130: Recording section 200: Measurement Department 300: Charging and discharging unit

Claims

1. a data acquisition unit configured to acquire battery information including the voltage and current of the battery during a charging cycle of the battery; a control unit configured to calculate a constant current charging capacity ratio and a constant voltage charging capacity ratio during the charging cycle based on the battery information, and to determine a type of deterioration of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

2. The control unit 2. The battery diagnostic device according to claim 1, wherein the total charging capacity in the charging cycle is divided into a constant current charging capacity and a constant voltage charging capacity, and the constant current charging capacity ratio and the constant voltage charging capacity ratio are calculated based on the total charging capacity, the constant current charging capacity, and the constant voltage charging capacity, respectively.

3. The control unit 3. The battery diagnostic device according to claim 2, configured to calculate the constant current charge capacity ratio and the constant voltage charge capacity ratio when the total charge capacity of the battery decreases during a charge cycle of the battery.

4. The control unit 3. The battery diagnostic device according to claim 2, wherein the type of deterioration of the battery is diagnosed as capacity deterioration or combined deterioration based on an increase or decrease in the constant current charging capacity ratio and the constant voltage charging capacity ratio.

5. The control unit 5. The battery diagnostic device according to claim 4, wherein the rate of change of the constant current charging capacity ratio is compared with a predetermined first rate of change, and the rate of change of the constant voltage charging capacity ratio is compared with a predetermined second rate of change.

6. The control unit 6. The battery diagnostic device according to claim 5, wherein if a rate of change of the constant current charging capacity ratio is less than the first rate of change and a rate of change of the constant voltage charging capacity ratio is equal to or greater than the second rate of change, the type of deterioration of the battery is diagnosed as the combined deterioration.

7. The control unit 6. The battery diagnostic device according to claim 5, wherein, when a rate of change of the constant current charging capacity ratio is equal to or greater than the first rate of change and a rate of change of the constant voltage charging capacity ratio is less than the second rate of change, the type of deterioration of the battery is diagnosed as capacity deterioration.

8. The control unit The battery diagnostic device according to claim 4 , wherein if the type of deterioration of the battery is diagnosed as the combined deterioration, a charge cutoff condition of the battery is changed.

9. The control unit 9. The battery diagnostic device according to claim 8, wherein if the type of deterioration of the battery is diagnosed as the combined deterioration, the cutoff voltage of the charge cutoff condition is reduced.

10. The control unit 9. The battery diagnostic device according to claim 8, wherein if the type of deterioration of the battery is diagnosed as the combined deterioration, the charge cutoff current of the charge cutoff conditions is increased.

11. The control unit The battery diagnostic device according to claim 8 , wherein if the type of deterioration of the battery is diagnosed as the combined deterioration, the cutoff time of the charge cutoff condition is reduced.

12. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 11.

13. acquiring battery information including a voltage and a current of the battery during a charging cycle of the battery; calculating a constant current charge capacity ratio and a constant voltage charge capacity ratio during the charging cycle based on the battery information; determining a type of deterioration of the battery based on the constant current charging capacity ratio and the constant voltage charging capacity ratio.

Images