Battery diagnostic device and method

Abstract

A battery diagnostic method according to an embodiment of the present invention comprises: a differential profile generation step of generating a differential profile indicating a relationship between a voltage of a battery and a differential capacity obtained by differentiating a capacity of the battery with respect to the voltage, at every predetermined diagnosis period; a target peak detection step of detecting a target peak, among the peaks of the differential profile, at which a differential capacity value decreases and then increases or a voltage value decreases and then increases as the usage time of the battery increases; a peak information acquisition step of acquiring target peak information including the differential capacity value and the voltage value of the target peak from each of a plurality of differential profiles generated while the diagnosis period is repeated a plurality of times; and a diagnosis step of diagnosing a state of the battery on the basis of the pieces of target peak information acquired from the plurality of differential profiles.

Description

Battery diagnostic device and method

[0001] This application claims priority from Korean Patent Application No. 10-2024-0015291, filed January 31, 2024, the entire disclosure of which is 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 for non-destructively diagnosing a rechargeable battery.

[0003] Recently, as the demand for portable electronic products such as laptops, digital cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage systems, robots, and satellites has been in full swing, research on high-performance, rechargeable, and high-energy-density batteries is actively being conducted.

[0004] Rechargeable batteries include lithium batteries that utilize lithium ions, such as lithium-ion batteries and lithium-ion polymer batteries, as well as nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. Among these, lithium batteries offer a relatively long lifespan due to minimal memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density. Consequently, their application scope is gradually expanding.

[0005] The positive and negative electrodes of these batteries gradually deteriorate as they undergo repeated charge and discharge cycles, losing their original electrical capacity. Therefore, accurate diagnosis of battery condition is essential to accurately predict the battery's usable lifespan, remaining service life, and replacement timing.

[0006] However, existing technologies simply diagnose batteries through the SOH (State of Health) of the entire battery, which reduces the accuracy and reliability of the diagnosis results, making it difficult to efficiently manage the current state of the battery.

[0007] The technical problem to be solved by the present invention is to provide a battery diagnosis device and method that enables real-time diagnosis of the state of a battery while improving the accuracy and reliability of the diagnosis results.

[0008] Another technical problem to be solved by the present invention is to provide a battery diagnosis device and method that enable efficient battery management.

[0009] According to one aspect of the present invention, a battery diagnosis method includes: a differential profile generation step of generating a differential profile representing a relationship between a differential capacity obtained by differentiating a capacity of a battery with respect to a voltage of the battery and the voltage at each predetermined diagnosis period; a target peak detection step of detecting a target peak, among peaks of the differential profile, in which a differential capacity value decreases and then increases or a voltage value decreases and then increases as the usage time of the battery increases; a peak information acquisition step of acquiring target peak information including a differential capacity value and a voltage value of the target peak from each of a plurality of differential profiles generated while the diagnosis period is repeated a plurality of times; and a diagnosis step of detecting, based on target peak information acquired from the plurality of differential profiles, a trend transition point at which a change trend of at least one of the differential capacity value and the voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time, and diagnosing a state of the battery with reference to the trend transition point.

[0010] In one embodiment, the target peak detection step may include: dividing the entire voltage section of the differential profile into a plurality of different sub-sections, and determining a target sub-section among the plurality of sub-sections; and detecting a peak located in the target sub-section among the peaks of the differential profile as the target peak.

[0011] In one embodiment, the target sub-interval may be a range from 4.0 [V] to 4.2 [V].

[0012] In one embodiment, the diagnosis step may include: detecting a first trend transition point at which a change trend of the differential capacity value transitions from a decreasing trend to an increasing trend over time; and determining a state of the battery before the first trend transition point as a first deterioration state and determining a state of the battery after the first trend transition point as a second deterioration state.

[0013] In one embodiment, the diagnosis step may further include a step of determining that the time to replace the battery has arrived when, after the first trend change point, the differential capacity value of the target peak exceeds a predetermined first threshold value.

[0014] In one embodiment, the diagnosis step may include: detecting a second trend transition point at which the change trend of the voltage value changes from an increasing trend to a decreasing trend over time; and determining the state of the battery before the second trend transition point as a third deterioration state, and determining the state of the battery after the second trend transition point as a fourth deterioration state.

[0015] In one embodiment, the diagnosis step may further include a step of determining that the time to replace the battery has arrived when the voltage value of the target peak decreases below a predetermined second threshold value after the second trend change point.

[0016] In one embodiment, the battery diagnosis method may further include a battery management step of lowering the upper voltage limit value of the battery when the trend change point is detected in the diagnosis step.

[0017] In one embodiment, the battery management step may include: calculating a difference between a first voltage value of the target peak obtained from a latest differential profile generated most recently among the plurality of differential profiles and a second voltage value of the target peak obtained from a differential profile generated immediately before the latest differential profile; and lowering an upper voltage limit of the battery in response to the difference.

[0018] According to another aspect of the present invention, a battery diagnosis device includes: a differential profile generation unit that generates a differential profile representing a relationship between a differential capacity obtained by differentiating a capacity of a battery with respect to a voltage of the battery and the voltage at each predetermined diagnosis cycle; a peak information acquisition unit that detects a target peak in which a differential capacity value decreases and then increases or a voltage value decreases and then increases as the usage time of the battery increases among peaks of the differential profile, and acquires target peak information including a differential capacity value and a voltage value of the target peak from each of a plurality of differential profiles generated while the diagnosis cycle is repeated a plurality of times; and a diagnosis unit that detects, based on target peak information acquired from the plurality of differential profiles, a trend transition point at which a change trend of at least one of the differential capacity value and the voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time, and diagnoses a state of the battery with reference to the trend transition point.

[0019] In one embodiment, the diagnostic unit may be configured to detect a first trend transition point at which a change trend of the differential capacity value transitions from a decreasing trend to an increasing trend over time, determine the state of the battery before the first trend transition point as a first deterioration state, and determine the state of the battery after the first trend transition point as a second deterioration state.

[0020] In one embodiment, the diagnostic unit may be configured to detect a second trend transition point at which the change trend of the voltage value transitions from an increasing trend to a decreasing trend over time, determine the state of the battery before the second trend transition point as a third deterioration state, and determine the state of the battery after the second trend transition point as a fourth deterioration state.

[0021] In one embodiment, the battery diagnostic device may further include a battery management unit configured to lower the upper voltage limit value of the battery when the trend change point is detected.

[0022] A battery pack according to another aspect of the present invention includes the battery diagnostic device described above.

[0023] A vehicle according to another aspect of the present invention includes the battery diagnostic device described above.

[0024] According to one embodiment of the present invention, the state of the battery can be diagnosed in real time by generating a differential profile representing the relationship between the differential capacity of the battery and the voltage of the battery at a predetermined diagnostic cycle and diagnosing the battery.

[0025] In addition, according to one embodiment of the present invention, by detecting a target peak that exhibits a peculiar behavior over time among the peaks appearing in the differential profile, and diagnosing the battery based on a change trend of at least one of the differential capacity value and voltage value of the target peak, the change in the state of the battery can be precisely confirmed, and the accuracy and reliability of the diagnosis result can be improved.

[0026] In addition, according to one embodiment of the present invention, by reducing the voltage upper limit of the battery in response to the difference between the first voltage value of the target peak obtained from the latest differential profile generated most recently among a plurality of differential profiles generated for each main cycle and the second voltage value of the target peak obtained from the differential profile generated immediately before the latest differential profile, efficient management corresponding to the current state of the battery is possible, and the lifespan of the battery can be extended and safety can be improved.

[0027] Furthermore, those skilled in the art will readily understand from the following description that various embodiments of the present invention can solve various technical problems not mentioned above.

[0028] FIG. 1 is a block diagram showing a battery diagnostic device according to one embodiment of the present invention.

[0029] Figure 2 is a diagram showing an example of a capacity-voltage profile.

[0030] Figure 3 is a drawing showing an example of a differential profile.

[0031] Figure 4 is a graph showing the general trend of how the differential capacity value of the peak of the differential profile changes over time.

[0032] Figure 5 is a graph showing the general trend of how the voltage value of the peak of the differential profile changes over time.

[0033] Figure 6 is an enlarged view showing the A1 area of ​​the differential profile shown in Figure 3.

[0034] Figure 7 is a drawing showing the location of the target peak at the beginning of the battery life.

[0035] Figure 8 is a drawing showing the location of the target peak at the end of the battery life.

[0036] Figure 9 is a graph showing the trend of changes in the differential capacity value of the target peak over time.

[0037] Figure 10 is a graph showing the trend of changes in the voltage value of the target peak over time.

[0038] Fig. 11 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0039] FIG. 12 is a flowchart illustrating a battery management process of a battery diagnosis method according to one embodiment of the present invention.

[0040] FIG. 13 is a drawing showing a battery pack according to one embodiment of the present invention.

[0041] Fig. 14 is a drawing showing a vehicle according to one embodiment of the present invention.

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings to clarify solutions corresponding to the technical challenges of the present invention. However, when describing the present invention, descriptions of related known technologies may be omitted if they obscure the gist of the present invention. Furthermore, the terms used in this specification are defined in consideration of their functions in the present invention, and these may vary depending on the intentions or practices of designers, manufacturers, etc. Therefore, the definitions of terms described below should be based on the contents throughout this specification.

[0043] FIG. 1 is a block diagram showing a battery diagnostic device (100) according to one embodiment of the present invention.

[0044] As illustrated in FIG. 1, a battery diagnostic device (100) according to one embodiment of the present invention includes a control unit (110). The control unit (110) controls the overall operation of the battery diagnostic device (100) and is configured to diagnose a rechargeable battery in a non-destructive manner.

[0045] The control unit (110) may include at least one general-purpose processor or at least one application-specific integrated circuit (ASIC) for executing battery diagnosis logic, and may optionally further include hardware such as registers and memories according to embodiments. The control unit (110) may be configured with a combination of hardware such as a processor and software such as a computer program. That is, the battery diagnosis logic of the control unit (110) may be configured as a computer program and stored in the control unit's (110) own memory or a storage unit (140) described below, and the stored computer program may be configured to be executed through the hardware of the control unit (110).

[0046] Meanwhile, the control unit (110) includes, as detailed components, a differential profile generation unit (112), a peak information acquisition unit (114), and a diagnosis unit (116).

[0047] The above differential profile generation unit (112) is configured to generate a differential profile representing the relationship between the differential capacity obtained by differentiating the capacity of the battery to be diagnosed with respect to the voltage of the battery, and the voltage, at each predetermined diagnostic cycle.

[0048] For example, when the diagnostic cycle arrives, the differential profile generation unit (112) can generate a profile indicating the relationship between the capacity and voltage of the battery by measuring the electrical values ​​of the battery while the battery is being charged or discharged.

[0049] Next, the differential profile generation unit (112) can generate the differential profile by differentiating the profile with respect to the voltage of the battery.

[0050] The above peak information acquisition unit (114) is configured to detect a target peak whose differential capacity value decreases and then increases or whose voltage value decreases and then increases as the usage time of the battery increases, among the peaks appearing in the differential profile, and to acquire target peak information from each of a plurality of differential profiles generated while the diagnosis cycle is repeated a plurality of times.

[0051] The above target peak information includes the differential capacity value and voltage value of the target peak shown in each of the above differential profiles.

[0052] In one embodiment, the peak information acquisition unit (114) divides the entire voltage section of each differential profile into a plurality of different sub-sections, determines a target sub-section among the plurality of sub-sections, and detects a peak located in the target sub-section among the peaks appearing in each differential profile as the target peak.

[0053] In this case, the target sub-interval can be determined as an interval from 4.0[V] to 4.2[V].

[0054] In this way, the peak information acquisition unit (114) can reduce the amount of computation required for target peak detection and shorten the target peak detection time by determining in advance the target sub-interval in which the target peak is detected.

[0055] The above diagnostic unit (116) checks the change trend over time of the differential capacity value and voltage value of the target peak based on the target peak information obtained from the plurality of differential profiles, and diagnoses the battery based on the checked change trend.

[0056] In particular, the diagnostic unit (116) detects, based on the target peak information, a trend change point at which at least one of the differential capacity value and voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time, and diagnoses the state of the battery with reference to the trend change point.

[0057] For example, the diagnostic unit (116) can determine that a change in the state of the battery has occurred when the change trend of the differential capacity value changes from a first trend in which the differential capacity value gradually decreases over time to a second trend in which the differential capacity value gradually increases over time.

[0058] That is, the diagnostic unit (116) can detect a first trend transition point at which the change trend of the differential capacity value changes from a decreasing trend to an increasing trend over time, and determine the state of the battery before the first trend transition point as a first deterioration state, and determine the state of the battery after the first trend transition point as a second deterioration state that is different from the first deterioration state.

[0059] For example, the first deterioration state may be a state requiring control over the charging and discharging conditions of the battery. Furthermore, the second deterioration state may be a state requiring a reduction in the upper voltage limit of the battery.

[0060] In one embodiment, the diagnostic unit (116) may determine that the time for replacing the battery has arrived when the differential capacity value of the target peak exceeds a predetermined first threshold value over time after the first trend change point.

[0061] In addition, the diagnostic unit (116) can determine that a change in the state of the battery has occurred when the change trend of the voltage value changes from a third trend in which the voltage value gradually increases over time to a fourth trend in which the voltage value gradually decreases over time.

[0062] For example, the diagnostic unit (116) can detect a second trend transition point at which the change trend of the voltage value changes from an increasing trend to a decreasing trend over time, determine the state of the battery before the second trend transition point as a third deterioration state, and determine the state of the battery after the second trend transition point as a fourth deterioration state that is different from the third deterioration state.

[0063] For example, the third deterioration state may be a state requiring control over the charging and discharging conditions of the battery. Furthermore, the fourth deterioration state may be a state requiring a reduction in the upper voltage limit of the battery.

[0064] In one embodiment, the diagnostic unit (116) may determine that the time to replace the battery has arrived when the voltage value of the target peak decreases below a predetermined second threshold value over time after the second trend change point.

[0065] In one embodiment, the diagnostic unit (116) can determine that a change in the state of the battery has occurred when the change trend of the differential capacity value changes from a decreasing trend to an increasing trend and the change trend of the voltage value changes from an increasing trend to a decreasing trend.

[0066] In addition, the diagnostic unit (116) can determine that the time for replacing the battery has arrived when the differential capacity value of the target peak exceeds the first threshold value or the voltage value of the target peak decreases below a predetermined second threshold value after the change trend of the differential capacity value changes from a decreasing trend to an increasing trend and the change trend of the voltage value changes from an increasing trend to a decreasing trend.

[0067] In one embodiment, the control unit (110) may further include a diagnosis result notification unit (118a). The diagnosis result notification unit (118a) may be configured to output a visual, auditory, or audiovisual notification signal corresponding to the diagnosis result of the battery using a predetermined output device.

[0068] In one embodiment, the control unit (110) may further include a battery management unit (118b). The battery management unit (118b) may be configured to control charging conditions and / or discharging conditions of the battery based on the diagnosis results of the diagnosis unit (116).

[0069] For example, the battery management unit (118b) can control the charging / discharging device (16) described later to appropriately adjust the voltage range of the battery, the current rate of the charging current and / or discharging current of the battery, etc. In addition, the battery management unit (118b) can also control the cooling device (18) described later to lower the temperature of the battery.

[0070] In one embodiment, when the battery is diagnosed to have deteriorated, the battery management unit (118b) may be configured to reduce the voltage of the battery upon completion of charging in response to the difference between the current voltage value of the target peak and a predetermined reference voltage value. The reference voltage value may be a voltage value of the target peak measured at the beginning of life (BOL) point of the battery, or a voltage value determined during the design of the battery.

[0071] In one embodiment, the battery management unit (118b) may be configured to lower the voltage upper limit value of the battery when the first or second trend change point described above is detected.

[0072] For example, the battery management unit (118b) can calculate the difference between the current voltage value of the target peak obtained from the latest differential profile generated most recently among the plurality of differential profiles generated for each diagnosis cycle and the previous voltage value of the target peak obtained from the differential profile generated immediately before the latest differential profile.

[0073] And the battery management unit (118b) can lower the voltage upper limit of the battery in response to the calculated difference value.

[0074] The differential profile generation unit (112), peak information acquisition unit (114), diagnosis unit (116), diagnosis result notification unit (118a), and battery management unit (118b) of the above-described control unit (110) may be implemented as a combination of a processor and a program executed by the processor. In this case, the control unit (110) may be implemented as a single processor or as two or more processors that are interconnected.

[0075] In one embodiment, the battery diagnostic device (100) may further include a communication unit (120). The communication unit (120) may be configured to receive data transmitted from other servers or communication terminals via a wired and / or wireless communication network and transmit the data to the control unit (110), or transmit control signals, diagnostic data, etc. processed by the control unit (110) to other servers or communication terminals. To this end, the communication unit (120) may include a communication modem that performs wired / wireless communication.

[0076] In one embodiment, the battery diagnostic device (100) may further include an input unit (130). The input unit (130) may be configured to receive commands or data from a system operator or administrator. To this end, the input unit (130) may include an input device such as a keyboard, operation buttons, or a touch panel.

[0077] In one embodiment, the battery diagnostic device (100) may further include a storage unit (140). The storage unit (140) may be configured to store and manage data necessary for the operation of the battery diagnostic device (100). To this end, the storage unit (140) may include one or two or more of a ROM, a RAM, an EEPROM, a register, a flash memory, a CD-ROM, a magnetic tape, a hard disk, a floppy disk, and an optical data recording device.

[0078] In one embodiment, the battery diagnostic device (100) may further include an output unit (150). The output unit (150) may be configured to visually, audibly, or audiovisually output a notification signal of the diagnostic result notification unit (118a). To this end, the output unit (150) may include a visual output device such as a light-emitting diode, a monitor, a display panel, or a touch screen. In addition, the output unit (150) may further include a sound generating device such as a speaker.

[0079] In one embodiment, the battery diagnostic device (100) may be configured to be linked with a measuring device (12) that measures the voltage, charging current, and / or discharging current of the battery, a communication device (14) that communicates with another device, a charging / discharging device (16) that charges / discharges the battery, a cooling device (18) that cools the battery, etc.

[0080] In another embodiment, the battery diagnostic device (100) according to the present invention may include one or two or more of the above-described measuring device (12), communication device (14), charging / discharging device (16), and cooling device (18).

[0081] Figure 2 is a diagram showing an example of a capacity-voltage profile (BP).

[0082] As illustrated in FIG. 2, when a diagnosis cycle arrives, the differential profile generation unit (112) can measure the electrical values ​​of the battery while the battery is being charged or discharged, and generate a profile (BP) that represents the relationship between the capacity and voltage of the battery.

[0083] In this case, the differential profile generation unit (112) can find a positive profile (PP) and a negative profile (NP) that generate a curve similar to the profile (BP) of the battery through mutual combination, and provide the starting point (pi) and the ending point (pf) of the positive profile (PP) and the starting point (ni) and the ending point (nf) of the negative profile (NP) to the diagnosis unit (116). The diagnosis unit (116) can use the starting point (pi) and the ending point (pf) of the positive profile (PP) and the starting point (ni) and the ending point (nf) of the negative profile (NP) as diagnosis factors indicating the state of the battery.

[0084] In addition, the differential profile generation unit (112) can generate a differential profile by differentiating the profile (BP) with respect to the voltage of the battery.

[0085] Figure 3 is a drawing showing an example of a differential profile (DP).

[0086] As illustrated in FIG. 3, the differential profile generation unit (112) is configured to generate a differential capacity (dQ / dV) obtained by differentiating the capacity of the battery with respect to the voltage of the battery, and a differential profile (DP1) representing the relationship between the voltage, at each predetermined diagnostic cycle.

[0087] Then, the peak information acquisition unit (114) is configured to acquire target peak information from each differential profile generated for each diagnosis cycle. Here, the target peak information may include a differential capacity value and voltage value of a target peak (P5) detected among a plurality of peaks (P1 to P5) of the corresponding differential profile (DP1).

[0088] The target peak (P5) above is a peak that exhibits a peculiar behavior as the battery's usage time increases. That is, the target peak (P5) may be a peak whose differential capacity value decreases and then increases, or whose voltage value decreases and then increases, as the battery's usage time increases.

[0089] That is, the entire voltage section of the differential profile (DP1) can be divided into a plurality of sub-sections (S1 to S5) based on the peaks (P1 to P5) of the differential profile (DP1).

[0090] Among these multiple sub-intervals (S1 to S5), a target sub-interval (S5) in which a peak exhibits a different behavior from other peaks over time may be determined in advance. The target sub-interval (S5) may be determined as an interval from 4.0 [V] to 4.2 [V].

[0091] For example, the peak information acquisition unit (114) can detect a peak (P5) located in a target sub-section (S5) among a plurality of peaks (P1 to P5) of each differential profile as the target peak.

[0092] Figure 4 is a graph showing the general trend of how the differential capacity value of the peak of the differential profile changes over time.

[0093] Figure 5 is a graph showing the general trend of how the voltage value of the peak of the differential profile changes over time.

[0094] As illustrated in FIGS. 4 and 5, among the multiple peaks (P1 to P5) of the differential profile (DP1), except for the target peak (P5), the other peaks exhibit a trend in which the differential capacity value, i.e., intensity, decreases and the voltage value increases as time elapses or the number of charge / discharge cycles increases. This trend is analyzed to be due to a loss of positive electrode capacity and an increase in resistance of the battery.

[0095] On the other hand, the target peak (P5) shows a different trend from the trends shown in FIGS. 4 and 5.

[0096] Figure 6 is an enlarged view showing the A1 area of ​​the differential profile shown in Figure 3.

[0097] As illustrated in FIG. 6, the target peak (P5) of the differential profile (DP1) generated at the BOL point of the battery may have a voltage value V1.

[0098] Figure 7 is a drawing showing the position of the target peak (P5') at the beginning of the battery life.

[0099] As illustrated in FIG. 7, the target peak (P5') of the differential profile (DP2) generated at the beginning of the battery's life may have a voltage value V2 that is greater than the previous voltage value V1, as in the general trend mentioned above, with its differential capacity value decreasing.

[0100] Figure 8 is a drawing showing the location of the target peak (P5") at the end of the battery life.

[0101] As illustrated in FIG. 8, the target peak (P5") of the differential profile (DP3) generated at the end of the battery's life may have a differential capacity value that increases and a voltage value that is lower than the voltage value V1, contrary to the general trend mentioned above.

[0102] The peculiar behavior of these target peaks (P5, P5', P5") is associated with a loss of anode capacity and an increase in internal resistance of the battery.

[0103] Accordingly, the diagnostic unit (116) can check the change trend of the differential capacity value and voltage value of the target peak over time based on the peak information obtained while the diagnostic cycle is repeated multiple times, and can diagnose the battery based on the checked change trend.

[0104] In addition, when the battery management unit (118b) is diagnosed as having deteriorated, the battery management unit (118b) can extend the life of the battery and ensure the safety of the battery by reducing the voltage upper limit of the battery, i.e., the voltage value of the battery at which charging of the battery ends, in response to the difference (ΔV) between the current voltage value V3 and the voltage value V1 of the target peak (P5").

[0105] Figure 9 is a graph showing the trend of changes in the differential capacity value of the target peak over time.

[0106] As illustrated in FIG. 9, the trend of change in the differential capacity value of the target peak (P5) described above may show a first trend (TL1) that gradually decreases over time, and then change to a second trend (TL2) that gradually increases over time after the first trend transition point (t1).

[0107] In this case, the diagnostic unit (116) can detect a first trend transition point (t1) at which the change trend of the differential capacity value changes from a decreasing trend to an increasing trend over time, and determine the state of the battery before the first trend transition point (t1) as a first deterioration state, and determine the state of the battery after the first trend transition point (t1) as a second deterioration state different from the first deterioration state.

[0108] Figure 10 is a graph showing the trend of changes in the voltage value of the target peak over time.

[0109] As illustrated in FIG. 10, the voltage value change trend of the target peak (P5) described above may show a third trend (TL3) that gradually increases over time, and then change to a fourth trend (TL4) that gradually decreases over time from the second trend change point (t3).

[0110] In this case, the diagnostic unit (116) can detect a second trend transition point (t3) at which the change trend of the voltage value changes from a decreasing trend to an increasing trend over time, and determine the state of the battery before the second trend transition point (t3) as a third deterioration state, and determine the state of the battery after the second trend transition point (t3) as a fourth deterioration state that is different from the third deterioration state.

[0111] Fig. 11 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0112] As illustrated in FIG. 11, the battery diagnosis method according to the present invention is a method for diagnosing a rechargeable battery in a non-destructive manner, and can be performed by a processor.

[0113] First, the processor generates a differential profile representing the relationship between the differential capacity of the battery to be diagnosed and the voltage of the battery, at each predetermined diagnostic cycle (S10).

[0114] For example, when the diagnostic cycle arrives, the processor may measure electrical values ​​of the battery while the battery is being charged or discharged, and generate a profile representing the relationship between the capacity and voltage of the battery.

[0115] And, the processor can generate the differential profile by differentiating the profile with respect to the voltage of the battery.

[0116] Next, the processor detects a target peak whose differential capacity value decreases and then increases or whose voltage value decreases and then increases as the usage time of the battery increases, among the peaks appearing in the differential profile, and acquires and stores target peak information from each of a plurality of differential profiles generated while the diagnosis cycle is repeated a plurality of times (S20).

[0117] In this case, the target peak information includes the differential capacity value and voltage value of the target peak shown in each of the differential profiles.

[0118] In one embodiment, the processor may divide the entire voltage section of each differential profile into a plurality of different sub-sections, determine a target sub-section among the plurality of sub-sections, and detect a peak located in the target sub-section among peaks appearing in each differential profile as the target peak.

[0119] In this case, the target sub-interval can be determined as an interval from 4.0[V] to 4.2[V].

[0120] In this way, the processor can reduce the amount of computation required for target peak detection and shorten the target peak detection time by determining in advance the target sub-interval in which the target peak is detected.

[0121] Next, the processor, based on the target peak information obtained from the plurality of differential profiles, checks the change trend of the differential capacity value and voltage value of the target peak over time, and diagnoses the battery based on the checked change trend (S30).

[0122] In particular, the processor detects a trend transition point at which a change trend of at least one of a differential capacity value and a voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time based on the target peak information, and diagnoses the state of the battery with reference to the trend transition point.

[0123] For example, the processor may determine that deterioration or a change in the deterioration state of the battery has occurred when the change trend of the differential capacity value changes from a first trend in which the differential capacity value gradually decreases over time to a second trend in which the differential capacity value gradually increases over time (S40).

[0124] That is, the processor can detect a first trend transition point at which the change trend of the differential capacity value changes from a decreasing trend to an increasing trend over time, determine the state of the battery before the first trend transition point as a first deterioration state, and determine the state of the battery after the first trend transition point as a second deterioration state that is different from the first deterioration state.

[0125] For example, the first deterioration state may be a state requiring control over the charging and discharging conditions of the battery. Furthermore, the second deterioration state may be a state requiring a reduction in the upper voltage limit of the battery.

[0126] In one embodiment, the processor may determine that it is time to replace the battery when, after the first trend change point, the differential capacity value of the target peak exceeds a predetermined first threshold value over time.

[0127] Additionally, the processor may determine that the battery has deteriorated or has a change in deterioration status when the change trend of the voltage value changes from a third trend in which the voltage value gradually increases over time to a fourth trend in which the voltage value gradually decreases over time.

[0128] For example, the processor may detect a second trend transition point at which the change trend of the voltage value changes from an increasing trend to a decreasing trend over time, determine the state of the battery before the second trend transition point as a third deterioration state, and determine the state of the battery after the second trend transition point as a fourth deterioration state that is different from the third deterioration state.

[0129] For example, the third deterioration state may be a state requiring control over the charging and discharging conditions of the battery. Furthermore, the fourth deterioration state may be a state requiring a reduction in the upper voltage limit of the battery.

[0130] In one embodiment, the processor may determine that it is time to replace the battery when, after the second trend change point, the voltage value of the target peak decreases below a predetermined second threshold value over time.

[0131] In one embodiment, the processor may determine that a change in the state of the battery has occurred when the change trend of the differential capacity value changes from a decreasing trend to an increasing trend and when the change trend of the voltage value changes from an increasing trend to a decreasing trend.

[0132] In addition, the processor may determine that the time for replacing the battery has arrived when the differential capacity value of the target peak exceeds the first threshold value or the voltage value of the target peak decreases below a predetermined second threshold value after the change trend of the differential capacity value changes from a decreasing trend to an increasing trend and the change trend of the voltage value changes from an increasing trend to a decreasing trend.

[0133] Next, the processor adjusts the charging conditions and / or discharging conditions of the battery according to the diagnosis results of the battery (S50).

[0134] For example, the processor can control the charging / discharging device (16) described with reference to FIG. 1 to appropriately adjust the voltage range of the battery, the current rate of the charging current and / or discharging current of the battery, etc. In addition, the battery management unit (118b) can control the cooling device (18) with reference to FIG. 1 to lower the temperature of the battery.

[0135] In one embodiment, when the battery is diagnosed to have deteriorated, the processor may be configured to reduce the voltage of the battery upon completion of charging in response to a difference between the current voltage value of the target peak and a predetermined reference voltage value. The reference voltage value may be a voltage value of the target peak measured at the beginning of life (BOL) point of the battery, or a voltage value determined during the design of the battery.

[0136] Meanwhile, the processor may output a visual, auditory or audiovisual notification signal corresponding to the diagnosis result of the battery using a predetermined output device.

[0137] Next, the processor may repeat the above-described steps (S10 to S50) at each diagnostic cycle until the battery is no longer in use (S60).

[0138] FIG. 12 is a flowchart illustrating a battery management process of a battery diagnosis method according to one embodiment of the present invention.

[0139] As illustrated in FIG. 12, the processor can determine a change trend over time of the differential capacity value and / or voltage value of the target peak based on a plurality of sequentially generated differential profiles (S51).

[0140] And, the processor can manage the battery in a different manner depending on whether a first trend transition point is detected where the differential capacity value change trend of the target peak changes from a decreasing trend to an increasing trend over time, or a second trend transition point is detected where the voltage value change trend of the target peak changes from an increasing trend to a decreasing trend over time.

[0141] If the first trend change point and the second trend change point are not detected, the processor can typically control the charging and discharging conditions of the battery. For example, the processor can lower the current rate of the charging current and / or the discharging current of the battery, or lower the temperature of the battery (S52, S53).

[0142] On the other hand, if at least one of the first trend change point and the second trend change point is detected, the processor can calculate a difference value between the current voltage value of the target peak obtained from the latest differential profile generated most recently among the plurality of differential profiles and the previous voltage value of the target peak obtained from the differential profile generated immediately before the latest differential profile (S54).

[0143] And the processor can lower the voltage upper limit of the battery in response to the calculated difference value (S55).

[0144] FIG. 13 is a drawing showing a battery pack (10) according to one embodiment of the present invention.

[0145] As illustrated in FIG. 13, the battery pack (10) includes a rechargeable battery (B) and a battery diagnostic device (100) according to the present invention. In one embodiment, the battery pack (10) may optionally further include a measuring device (12), a communication device (14), a charging / discharging device (16), and a cooling device (18).

[0146] The above measuring device (12) may be configured to measure the voltage and / or current of the battery (B). To this end, the measuring device (12) may include a voltage sensor for sensing the voltage of the battery (B) and / or a current sensor (12b) for sensing the current of the battery (B).

[0147] This measuring device (12) can measure the voltage of the battery (B) through the first sensing line (SL1) and the second sensing line (SL2). In addition, the measuring device (12) can measure the current of the battery (B) through the third sensing line (SL3) connected to the current measuring circuit (A). The current measuring circuit (A) may include a shunt resistor.

[0148] A battery diagnostic device (100) according to one embodiment of the present invention can obtain voltage values ​​of a battery (B) through the measuring device (12). For reference, the capacity of the battery (B) can be calculated by applying a current integration method.

[0149] The above communication unit (14) may be configured to perform communication with another device located remotely. For example, the communication unit (14) may be configured to receive data transmitted from a remote server or communication terminal via a wired and / or wireless communication network and transmit the data to the battery diagnosis device (100), or to transmit data generated in the battery diagnosis device (100) to another server or communication terminal. To this end, the communication unit (14) may include a communication modem that performs wired and / or wireless communication.

[0150] The above charging / discharging device (16) may be configured to charge and / or discharge the battery (B). To this end, the charging / discharging device (16) may include a charger for charging the battery (B), a discharger for discharging the battery (B), at least one switch for electrically connecting the battery (B) to terminals (T1, T2) of the battery pack (10), etc.

[0151] A battery diagnostic device (100) according to one embodiment of the present invention can control the charging / discharging device (16) to proceed with or stop charging or discharging of the battery (B), set charging / discharging conditions, or change set charging / discharging conditions.

[0152] The cooling device (18) may be configured to cool the battery (B). To this end, the cooling device (18) may include a heat sink that absorbs heat from the battery (B) and releases it to the outside.

[0153] Fig. 14 is a drawing showing a vehicle (2) according to one embodiment of the present invention.

[0154] As illustrated in FIG. 14, a vehicle (2) according to one embodiment of the present invention may include a battery pack (10) that provides electric energy required for the operation of the vehicle, and a battery diagnostic device (100) according to the present invention.

[0155] In this case, the battery diagnostic device (100) may be configured to be linked with an ECU (Electronic Control Unit) that controls the operation of the vehicle (2) or a BMS (Battery Management System) of the battery pack (10).

[0156] Additionally, the battery diagnostic device (100) may be configured to receive data transmitted from a remote server (4) via a wired and / or wireless communication network, or to transmit data generated in the battery diagnostic device (100) to the server (4).

[0157] For reference, the battery diagnostic device (100) according to the present invention can be applied to various electrical devices or electrical systems other than vehicles, and can also be applied to ESS (Energy Storage System).

[0158] Meanwhile, embodiments according to the present invention can be implemented as a computer system and a computer program that operates such a computer system. When embodiments of the present invention are implemented as a computer program, the components of the present invention may include program segments that execute corresponding operations or tasks through the computer system. Such computer programs or program segments may be stored on various computer-readable recording media. The computer-readable recording media may include all types of media that record data that can be read by a computer system. For example, the computer-readable recording media may include ROM, RAM, EEPROM, registers, flash memory, CD-ROM, magnetic tape, hard disk, floppy disk, or optical data recording devices. In addition, such recording media may be distributed across various network-connected computer systems to store or execute program codes in a distributed manner.

[0159] As described above, according to one embodiment of the present invention, by generating a differential profile representing the relationship between the differential capacity of the battery and the voltage of the battery at each predetermined diagnostic cycle and diagnosing the battery, the state of the battery can be diagnosed in real time.

[0160] In addition, according to one embodiment of the present invention, by detecting a target peak that exhibits a peculiar behavior over time among the peaks appearing in the differential profile, and diagnosing the battery based on a change trend of at least one of the differential capacity value and voltage value of the target peak, the change in the state of the battery can be precisely confirmed, and the accuracy and reliability of the diagnosis result can be improved.

[0161] In addition, according to one embodiment of the present invention, by reducing the voltage upper limit of the battery in response to the difference between the first voltage value of the target peak obtained from the latest differential profile generated most recently among a plurality of differential profiles generated for each main cycle and the second voltage value of the target peak obtained from the differential profile generated immediately before the latest differential profile, efficient management corresponding to the current state of the battery is possible, and the lifespan of the battery can be extended and safety can be improved.

[0162] Furthermore, it goes without saying that embodiments according to the present invention can solve various technical problems other than those mentioned in the present specification, not only in the relevant technical field but also in related technical fields.

[0163] The present invention has been described with reference to specific embodiments. However, those skilled in the art will clearly understand that various modifications can be implemented within the technical scope of the present invention. Therefore, the embodiments disclosed above should be considered illustrative rather than limiting. In other words, the true scope of the present invention is set forth in the claims, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. A differential profile generation step for generating a differential profile representing the relationship between the differential capacity and the voltage of the battery, which is obtained by differentiating the capacity of the battery with respect to the voltage of the battery, at each predetermined diagnostic cycle; A target peak detection step for detecting a target peak in which, among the peaks of the above differential profile, the differential capacity value decreases and then increases or the voltage value decreases and then increases as the usage time of the battery increases; A peak information acquisition step for acquiring target peak information including a differential capacity value and a voltage value of the target peak from each of a plurality of differential profiles generated while the above diagnostic cycle is repeated multiple times; and A battery diagnosis method comprising a diagnosis step of detecting a trend transition point at which a change trend of at least one of a differential capacity value and a voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time based on target peak information obtained from the plurality of differential profiles, and diagnosing the state of the battery by referring to the trend transition point.

2. In paragraph 1, The above target peak detection step is, A step of dividing the entire voltage section of the above differential profile into a plurality of different sub-sections and determining a target sub-section among the plurality of sub-sections; and A battery diagnosis method characterized by comprising a step of detecting a peak located in the target sub-interval among the peaks of the differential profile as the target peak.

3. In paragraph 2, A battery diagnosis method, characterized in that the above target sub-range is a range from 4.0[V] to 4.2[V].

4. In paragraph 1, The above diagnostic steps are: A step of detecting a first trend transition point at which the change trend of the above differential capacity value changes from a decreasing trend to an increasing trend over time; and A battery diagnosis method characterized by comprising a step of determining the state of the battery before the first trend change point as a first deterioration state and determining the state of the battery after the first trend change point as a second deterioration state.

5. In paragraph 4, The above diagnostic steps are: A battery diagnosis method characterized in that it further includes a step of determining that the time for replacing the battery has arrived when the differential capacity value of the target peak exceeds a predetermined first threshold value after the first trend change point.

6. In paragraph 1, The above diagnostic steps are: A step of detecting a second trend transition point at which the change trend of the voltage value changes from an increasing trend to a decreasing trend over time; and A battery diagnosis method characterized by comprising a step of determining the state of the battery before the second trend change point as a third deterioration state, and determining the state of the battery after the second trend change point as a fourth deterioration state.

7. In paragraph 6, The above diagnostic steps are: A battery diagnosis method characterized in that it further includes a step of determining that the time for replacing the battery has arrived when the voltage value of the target peak decreases below a predetermined second threshold value after the second trend change point.

8. In paragraph 1, A battery diagnosis method characterized in that it further includes a battery management step of lowering the upper voltage limit value of the battery when the trend change point is detected in the above diagnosis step.

9. In paragraph 8, The above battery management steps are: A step of calculating a difference value between a first voltage value of the target peak obtained from the latest differential profile generated most recently among the plurality of differential profiles and a second voltage value of the target peak obtained from a differential profile generated immediately before the latest differential profile; and A battery diagnosis method characterized by including a step of lowering the voltage upper limit of the battery in response to the difference value.

10. A differential profile generation unit that generates a differential profile representing the relationship between the differential capacity and the voltage of the battery, which is obtained by differentiating the capacity of the battery with respect to the voltage of the battery, at each predetermined diagnostic cycle; A peak information acquisition unit detects a target peak whose differential capacity value decreases and then increases or whose voltage value decreases and then increases as the usage time of the battery increases among the peaks of the differential profile, and acquires target peak information including the differential capacity value and voltage value of the target peak from each of a plurality of differential profiles generated while the diagnosis cycle is repeated a plurality of times; and A battery diagnosis device including a diagnosis unit that detects a trend transition point at which at least one of a differential capacity value and a voltage value of the target peak changes from an increasing trend to a decreasing trend or from a decreasing trend to an increasing trend over time based on target peak information obtained from the plurality of differential profiles, and diagnoses the state of the battery by referring to the trend transition point.

11. In paragraph 10, A battery diagnostic device characterized in that the diagnostic unit is configured to detect a first trend transition point at which a change trend of the differential capacity value changes from a decreasing trend to an increasing trend over time, and determine the state of the battery before the first trend transition point as a first deterioration state, and determine the state of the battery after the first trend transition point as a second deterioration state.

12. In paragraph 10, A battery diagnostic device characterized in that the diagnostic unit is configured to detect a second trend transition point at which the change trend of the voltage value changes from an increasing trend to a decreasing trend over time, determine the state of the battery before the second trend transition point as a third deterioration state, and determine the state of the battery after the second trend transition point as a fourth deterioration state.

13. In paragraph 10, A battery diagnostic device further comprising a battery management unit configured to lower the upper voltage limit value of the battery when the above trend change point is detected.

14. A battery pack comprising a battery diagnostic device according to any one of claims 10 to 13.

15. A vehicle including a battery diagnostic device according to any one of paragraphs 10 to 13.

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