Battery management device and method

Abstract

According to an embodiment of the present invention, a battery management device includes a side reaction determination unit configured to determine a target peak in a differential profile indicating a correspondence relationship between a voltage and a differential capacity of a battery, and to determine whether a side reaction has occurred in the battery by comparing a reference peak of a preset reference profile with the target peak; and a side reaction cause determination unit configured to determine a resistance pattern of the battery for a reference voltage range in a resistance profile indicating a correspondence relationship between the voltage and resistance of the battery, and to determine a cause of the side reaction based on the determined resistance pattern.

Description

[Technical field]

[0001] This application claims priority to Korean Patent Application No. 10-2022-0085324 filed on July 11, 2022, and Korean Patent Application No. 10-2023-0089416 filed on July 10, 2023, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings.

[0002] The present invention relates to a battery management device and method, and more particularly to a battery management device and method capable of diagnosing the state of a battery. [Background technology]

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

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among them, 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] While various research efforts are being made on the development of high-capacity and high-density batteries, it is also important to improve their lifespan and safety. To achieve this, it is necessary to suppress the decomposition reaction between the electrolyte and the surface of the electrodes, and to prevent overcharging and over-discharging.

[0006] In particular, it is necessary to prevent the phenomenon of lithium deposition on the surface of the negative electrode (lithium plating). If lithium deposits on the surface of the negative electrode, it can cause side reactions with the electrolyte and changes in the kinetic balance of the battery, which can lead to battery degradation. In addition, the deposition of lithium metal on the surface of the negative electrode can cause an internal short circuit in the battery, which can lead to fire and explosion due to the internal short circuit. Therefore, it is necessary to develop technology that can detect the deposition of lithium metal on the surface of the negative electrode. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery management device and method that can specifically diagnose the occurrence and cause of side reactions in a battery.

[0008] Other objects and advantages of the present invention can be understood from the following description and will become more apparent from the embodiments of the present invention. Also, the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0009] According to one aspect of the present invention, a battery management device includes a side reaction determination unit configured to determine a target peak in a differential profile indicating a correspondence relationship between a battery voltage and a differential capacity, and to determine whether a side reaction has occurred in the battery by comparing a reference peak of a preset reference profile with the target peak; and a side reaction cause determination unit configured to determine a resistance pattern of the battery for a reference voltage range in a resistance profile indicating a correspondence relationship between the battery voltage and resistance, and to determine a cause of the side reaction based on the determined resistance pattern.

[0010] The side reaction cause determining unit may be configured to determine that a cause of the side reaction is at least one of lithium deposition and an electrolyte side reaction based on the determined resistance pattern.

[0011] The side reaction cause determining unit may be configured to determine, as a first resistance pattern, a case in which the resistance decreases as the voltage increases in the reference voltage section of the resistance profile.

[0012] The side reaction cause determining unit may be configured to determine that the cause of the side reaction is lithium deposition when the determined resistance pattern is the first resistance pattern.

[0013] The side reaction cause determining unit may be configured to determine a second resistance pattern when the resistance of the resistance profile is equal to or greater than a resistance of a preset reference resistance profile in the reference voltage section of the resistance profile.

[0014] The side reaction cause determining unit may be configured to determine that the cause of the side reaction is the electrolyte side reaction when the determined resistance pattern is the second resistance pattern.

[0015] The battery management device according to an aspect of the present invention may further include a control unit configured to set a usage condition of the battery based on the determined cause of the side reaction.

[0016] The control unit may be configured to reduce an upper limit of a charge / discharge C-rate for the battery when the cause of the side reaction is determined to be lithium deposition.

[0017] The controller may be configured to reduce a temperature and an upper limit SOC for the battery if the cause of the side reaction is determined to be the electrolyte side reaction.

[0018] The side reaction determining unit may be configured to determine whether a side reaction has occurred in the battery by comparing a voltage of the target peak with a voltage of the reference peak.

[0019] The side reaction determining unit may be configured to determine that the side reaction has occurred if a voltage of the target peak exceeds a voltage of the reference peak.

[0020] The reference voltage section may be configured as a voltage section including a resistance ranging from a minimum resistance to a resistance equal to or lower than a predetermined critical resistance in a preset reference resistance profile.

[0021] A battery pack according to another aspect of the present invention includes a battery management device according to an aspect of the present invention.

[0022] According to yet another aspect of the present invention, a battery management method includes a target peak determining step of determining a target peak in a differential profile indicating a correspondence relationship between a battery voltage and a differential capacity, a side reaction determining step of determining whether a side reaction has occurred in the battery by comparing a reference peak of a preset reference profile with the target peak, a resistance pattern determining step of determining a resistance pattern of the battery for a reference voltage section in a resistance profile indicating a correspondence relationship between the battery voltage and resistance, and a side reaction cause determining step of determining a cause of the side reaction based on the determined resistance pattern.

[0023] According to another aspect of the present invention, the battery management method may further include, after the side reaction cause determining step, setting a use condition of the battery based on the determined cause of the side reaction. Effect of the Invention

[0024] According to one aspect of the present invention, the occurrence and cause of side reactions in a battery can be specifically diagnosed.

[0025] According to one embodiment of the present invention, the conditions of use of the battery can be set so as to correspond to the cause of the occurrence of a side reaction in the battery.

[0026] 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.

[0027] The following drawings attached to this specification, together with the detailed description of the invention described below, serve to further understand the technical ideas of the present invention, and the present invention should not be interpreted as being limited only to the matters described in the drawings. [Brief description of the drawings]

[0028] [Figure 1] 1 is a diagram illustrating a battery management device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram illustrating a differential profile of a first battery according to an embodiment of the present invention. [Diagram 3] FIG. 3 is an enlarged view showing a part of FIG. 2. [Figure 4] FIG. 2 is a schematic diagram illustrating a resistance profile of a first battery according to an embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram illustrating a differential profile of a second battery according to an embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged view showing a part of FIG. 5. [Figure 7] FIG. 4 is a schematic diagram illustrating a resistance profile of a second battery according to an embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. [Figure 9] 13 is a diagram illustrating a battery management method according to yet another embodiment of the present invention. [Figure 10] 13 is a diagram illustrating a battery management method according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The terms and words used in this specification and the 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, based on the principle that the inventor himself can appropriately define the concept of the term in order to explain the invention in the best possible way.

[0030] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment 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.

[0031] In addition, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may make the gist of the present invention unclear, the detailed description will be omitted.

[0032] Terms including ordinal numbers such as first, second, etc. are used to distinguish one of various components from other components, and are not intended to limit the components.

[0033] Throughout the specification, when a part "comprises" a certain element, this does not mean to exclude other elements, but means that it may further include other elements, unless otherwise specified.

[0034] 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" through other elements.

[0035] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0036] FIG. 1 is a schematic diagram of a battery management system 100 according to an embodiment of the present invention.

[0037] Here, the term "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 lithium ion battery or a lithium polymer battery may be considered as a battery. Also, the term "battery" may refer to a battery module in which a plurality of cells are connected in series and / or parallel. Hereinafter, for convenience of explanation, the term "battery" will be described as meaning a single independent cell.

[0038] Referring to FIG. 1, a battery management device 100 may include a side reaction determining unit 110 and a side reaction cause determining unit 120.

[0039] The side reaction determining unit 110 may be configured to determine a target peak in a differential profile D that indicates a corresponding relationship between the voltage and the differential capacity of the battery.

[0040] For example, the side reaction determination unit 110 may obtain battery information including the voltage and current of the battery. The side reaction determination unit 110 may directly receive the battery information or may access and extract pre-stored battery information. The side reaction determination unit 110 may generate a voltage profile indicating the correspondence between the voltage and capacity of the battery based on the obtained battery information. Then, the side reaction determination unit 110 may generate a differential profile D indicating the correspondence between the voltage and differential capacity based on the voltage profile. Here, the differential capacity is a value obtained by differentiating the capacity with respect to the voltage, and may be expressed as dQ / dV.

[0041] As another example, the side reaction determining unit 110 may directly measure battery information and generate a voltage profile based on the measured battery information, and may generate a differential profile D from the voltage profile.

[0042] For example, the voltage profile can be represented by an XY graph with the X-axis set to voltage and the Y-axis set to capacitance, and the differential profile D can be represented by an XY graph with the X-axis set to voltage and the Y-axis set to differential capacitance.

[0043] Specifically, the side reaction determination unit 110 may determine a plurality of peaks from the differential profile D. Here, the peak may be a point that has an upward convex shape and has a slope of 0. Preferably, the peaks of the differential profile D may correspond to inflection points of the voltage profile.

[0044] Then, the side reaction determination unit 110 may determine the peak having the lowest corresponding voltage among the determined peaks as the target peak. For example, the target peak may be a peak that falls within the range of 3.4 V to 3.5 V and is generally represented as Ea(1).

[0045] Fig. 2 is a diagram illustrating a schematic differential profile D of a first battery according to an embodiment of the present invention, and Fig. 3 is an enlarged view of a portion of Fig. 2. Specifically, Fig. 3 is an enlarged view of a portion A of Fig. 2.

[0046] 2 and 3, a first reference profile P1, a second reference profile P2, a first differential profile D1, and a second differential profile D2 are identified. Here, the first differential profile D1 is a differential profile D generated based on battery information measured during a charging process of the first battery. The second differential profile D2 is a differential profile D generated based on battery information measured during a discharging process of the first battery.

[0047] For example, in the embodiment of FIG. 3, the side reaction determiner 110 may determine a first target peak tp1 in the first derivative profile D1 and a second target peak tp2 in the second derivative profile D2.

[0048] The side reaction determining unit 110 may be configured to compare a reference peak of a preset reference profile P with a target peak to determine whether a side reaction occurs in the battery.

[0049] Here, the reference profile P may be a profile for a reference battery corresponding to the battery (e.g., a battery in a BOL (Beginning of Life) state). Specifically, the reference profile P may be a profile indicating the correspondence between the voltage and the differential capacity of the reference battery.

[0050] Also, the reference peak may be the peak with the lowest voltage in the reference profile P. For example, the method in which the target peak is determined in the differential profile D may be similarly applied to determine the reference peak in the reference profile P.

[0051] 2 and 3, the first reference profile P1 can correspond to the first derivative profile D1 and the second reference profile P2 can correspond to the second derivative profile D2. The first reference profile P1 can include a first reference peak rp1 and the second reference profile P2 can include a second reference peak rp2.

[0052] The side reaction determining unit 110 may determine whether a side reaction has occurred in the battery by comparing the first target peak tp1 with the first reference peak rp1. Alternatively, the side reaction determining unit 110 may determine whether a side reaction has occurred by comparing the second target peak tp2 with the second reference peak rp2. That is, although the differential profile D and the reference profile P corresponding to the charging and discharging of the battery are all shown in Figs. 2 and 3, the side reaction determining unit 110 may determine whether a side reaction has occurred from at least one of the charging and discharging states of the battery.

[0053] Specifically, the side reaction determining unit 110 may be configured to determine whether a side reaction occurs in the battery by comparing the voltage of the target peak with the voltage of the reference peak.

[0054] For example, in the embodiment of Fig. 3, the side reaction determining unit 110 may compare the voltage of the first target peak tp1 with the voltage of the first reference peak rp1. The side reaction determining unit 110 may determine that the voltage of the first target peak tp1 is greater than the voltage of the first reference peak rp1.

[0055] As another example, in the embodiment of Fig. 3, the side reaction determining unit 110 may compare the voltage of the second target peak tp2 with the voltage of the second reference peak rp2. The side reaction determining unit 110 may determine that the voltage of the second target peak tp2 is greater than the voltage of the second reference peak rp2.

[0056] The side reaction determining unit 110 may be configured to determine that a side reaction has occurred if the voltage of the target peak exceeds the voltage of the reference peak, or, conversely, the side reaction determining unit 110 may determine that a side reaction has not occurred if the voltage of the target peak is equal to or less than the voltage of the reference peak.

[0057] Initially, the target peak and the reference peak of the battery may be the same. However, if a side reaction occurs in the battery, the target peak (Ea(1) peak) appearing in the differential profile D of the battery may shift to a higher potential. Specifically, if available lithium in the battery is lost, the target peak may shift to a higher potential. For example, if lithium metal is deposited on the surface of the negative electrode of the battery or a side reaction of the electrolyte occurs, available lithium in the battery may be lost. As a result, the target peak appearing in the differential profile D of the battery may shift to a higher potential than the reference peak. Therefore, the side reaction determination unit 110 can determine whether a side reaction occurs in the battery by comparing the voltage of the target peak with the voltage of the reference peak.

[0058] For example, in the embodiment of FIG. 3, because the voltage of the first target peak tp1 exceeds the voltage of the first reference peak rp1, the side reaction determining unit 110 may determine that a side reaction has occurred in the first battery.

[0059] As another example, in the embodiment of FIG. 3, since the voltage of the second target peak tp2 exceeds the voltage of the second reference peak rp2, the side reaction determining unit 110 may determine that a side reaction has occurred in the first battery.

[0060] As yet another example, in the embodiment of FIG. 3, since the voltage of the first target peak tp1 exceeds the voltage of the first reference peak rp1 and the voltage of the second target peak tp2 exceeds the voltage of the second reference peak rp2, the side reaction determination unit 110 may determine that a side reaction has occurred in the first battery.

[0061] The side reaction cause determining unit 120 may be configured to determine a resistance pattern of the battery for the reference voltage section RR in a resistance profile indicating a correspondence relationship between the voltage and resistance of the battery.

[0062] FIG. 4 is a schematic diagram illustrating a resistance profile of a first battery according to an embodiment of the present invention.

[0063] For example, the resistance profile may be represented by an XY graph, where the X-axis is voltage and the Y-axis is resistance. Specifically, FIG. 4 shows a first resistance profile R1 and a first reference resistance profile RP1 for a battery.

[0064] The side reaction cause determination unit 120 may select a resistance corresponding to the reference voltage section RR from the resistance profile to determine the resistance pattern of the battery. Then, the side reaction cause determination unit 120 may determine a pattern between the selected multiple resistances.

[0065] For example, the reference voltage section may be a voltage section preset according to the resistance change rate according to the voltage in the reference resistance profile. In the embodiment of FIG. 4, it is confirmed that the resistance change rate with respect to the voltage changes suddenly with reference to the K voltage. For example, when the difference between the resistance change rate immediately before and immediately after each voltage included in the reference resistance profile is calculated, the difference in the resistance change rate corresponding to the K voltage (the difference between the resistance change rate immediately before and immediately after the K voltage) may be the largest. Therefore, the reference voltage section RR may be set to a voltage section corresponding to 4.2 [V] from the K voltage. That is, the reference voltage section RR may be a section in which the resistance change according to the voltage is small in the reference resistance profile. In other words, the reference voltage section RR may be a resistance plateau section included in the reference resistance profile.

[0066] As another example, the reference voltage section RR may be configured as a voltage section including a resistance from the minimum resistance to a predetermined critical resistance TH or less in a preset reference resistance profile. In the embodiment of FIG. 4, the minimum resistance in the first reference resistance profile RP1 may be LR corresponding to the L point. And, LR2 may be a value obtained by adding the critical resistance TH to the minimum resistance LR. For example, the critical resistance TH may be preset to a value of 0.1Ω or less. Preferably, the critical resistance TH may be preset to a value of 0.05Ω or less.

[0067] The reference voltage section RR may be defined as a voltage section equal to or greater than a voltage value corresponding to the LR2 resistor in the entire voltage section. Here, when there are multiple voltage values ​​corresponding to the LR2 resistor, the reference voltage section RR may be set based on the lowest voltage value among the multiple voltage values.

[0068] In the embodiment of Fig. 4, the resistances corresponding to the voltages K [V] to 4.2 [V] may be included within the range from the minimum resistance LR to the critical resistance TH. Therefore, the reference voltage range RR may be preset to K [V] to 4.2 [V]. Then, the side reaction cause determination unit 120 may determine a resistance pattern between a plurality of resistors corresponding to the reference voltage range of the resistance profile.

[0069] The side reaction cause determination unit 120 may be configured to determine a first resistance pattern when the resistance decreases as the voltage increases in the reference voltage section RR of the resistance profile. The side reaction cause determination unit 120 may be configured to determine a second resistance pattern when the resistance of the resistance profile is equal to or greater than the resistance of a preset reference resistance profile in the reference voltage section RR of the resistance profile.

[0070] Here, it should be noted that the first resistance pattern and the second resistance pattern are not mutually exclusive. That is, the resistance pattern of the battery may be determined as the first resistance pattern and the second resistance pattern. For example, if a first condition that the resistance decreases with increasing voltage in the reference voltage section RR of the resistance profile and a second condition that the resistance in the reference voltage section RR of the resistance profile is equal to or greater than the resistance in the reference voltage section RR of the reference resistance profile are both satisfied, the resistance pattern of the battery may be determined as the first resistance pattern and the second resistance pattern.

[0071] In the embodiment of FIG. 4, in the reference voltage section RR of the first resistance profile R1, the resistance decreases as the voltage increases, so that the side reaction cause determining unit 120 may determine the resistance pattern for the first battery as the first resistance pattern.

[0072] The side reaction cause determining unit 120 may be configured to determine the cause of the occurrence of the side reaction based on the determined resistance pattern.

[0073] Specifically, the side reaction cause determining unit 120 may be configured to determine that the cause of the occurrence of the side reaction is at least one of lithium deposition and an electrolyte side reaction based on the determined resistance pattern.

[0074] Here, lithium deposition means that lithium ions contained in the battery are deposited as metallic lithium on the surface of the negative electrode.

[0075] The electrolyte side reaction refers to a side reaction that occurs in the electrolyte (electrolyte solution) and reduces the performance of the battery. For example, the electrolyte side reaction refers to a side reaction that occurs in the electrolyte due to the reduction of the negative electrode.

[0076] The side reaction cause determining unit 120 may specifically determine the cause of the side reaction for the battery in which it is determined that a side reaction has occurred. That is, the cause of the loss of available lithium in the battery may be determined to be at least one of lithium precipitation and an electrolyte side reaction.

[0077] For example, the side reaction cause determining unit 120 may be configured to determine that the cause of the side reaction is lithium deposition when the determined resistance pattern is the first resistance pattern, whereas the side reaction cause determining unit 120 may be configured to determine that the cause of the side reaction is an electrolyte side reaction when the determined resistance pattern is the second resistance pattern.

[0078] In the embodiment of Fig. 4, the resistance pattern for the first battery may be determined as the first resistance pattern. Therefore, the side reaction cause determining unit 120 may determine that the cause of the side reaction of the first battery is lithium deposition. That is, the first battery may be a battery in which available lithium has been lost due to lithium plating, in which lithium metal is deposited on the surface of the negative electrode.

[0079] The battery management device 100 according to an embodiment of the present invention has an advantage in that it can diagnose not only whether a side reaction occurs in a battery but also the cause of the side reaction in detail. Therefore, the battery management device 100 can quickly detect an abnormal battery (especially a battery in which a side reaction has occurred) and can also detect the cause of the side reaction.

[0080] An embodiment for the second battery will be described below.

[0081] Fig. 5 is a diagram illustrating a schematic differential profile D of a second battery according to an embodiment of the present invention, and Fig. 6 is an enlarged view of a portion of Fig. 5. Specifically, Fig. 6 is an enlarged view of section A of Fig. 5.

[0082] 5 and 6 show a third differential profile D3, a fourth differential profile D4, a third reference profile P3, and a fourth reference profile P4 for the second battery. Here, the third reference profile P3 may correspond to the third differential profile D3, and the fourth reference profile P4 may correspond to the fourth differential profile D4. The third differential profile D3 is a differential profile D generated based on battery information measured during a charging process of the second battery. The fourth differential profile D4 is a differential profile D generated based on battery information measured during a discharging process of the second battery.

[0083] For example, the side reaction determining unit 110 may determine a third target peak tp3 in the third differential profile D3. Since the voltage of the third target peak tp3 is greater than the voltage of the third reference peak rp3, the side reaction determining unit 110 may determine that a side reaction has occurred in the second battery.

[0084] As another example, the side reaction determining unit 110 may determine a fourth target peak tp4 in the fourth differential profile D4. Since the voltage of the fourth target peak tp4 is greater than the voltage of the fourth reference peak rp4, the side reaction determining unit 110 may determine that a side reaction has occurred in the second battery.

[0085] As yet another example, since the voltage of the third target peak tp3 is greater than the voltage of the fourth reference peak rp4, and the voltage of the fourth target peak tp4 is greater than the voltage of the fourth reference peak rp4, the side reaction determination unit 110 may determine that a side reaction has occurred in the second battery.

[0086] 7 is a schematic diagram illustrating a resistance profile of a second battery according to an embodiment of the present invention, specifically, a second resistance profile R2 and a second reference resistance profile RP2 for the second battery.

[0087] 7, in the reference voltage section RR of the second resistance profile R2, the resistance is maintained within a certain range even when the voltage increases, so the side reaction cause determining unit 120 may determine the resistance pattern for the second battery as the second resistance pattern. That is, in the reference voltage section RR of the second resistance profile R2, the resistance does not decrease even when the voltage increases, so the side reaction cause determining unit 120 may determine the resistance pattern for the second battery as the second resistance pattern. Therefore, the side reaction cause determining unit 120 may determine that the cause of the side reaction of the second battery is an electrolyte side reaction.

[0088] Referring to FIG. 1, the battery management device 100 according to an embodiment of the present invention may further include a control unit 130.

[0089] The control unit 130 may be configured to set the usage conditions of the battery based on the determined cause of the side reaction.

[0090] Specifically, the battery use conditions may be preset for the charge / discharge C-rate (current rate), temperature range, and available SOC (State of charge) range. For example, the use conditions may be preset for the charge C-rate for the battery charge type (slow charge and fast charge), the discharge C-rate for the output required by the load, the upper limit temperature, the lower limit temperature, the upper limit SOC, and the lower limit SOC. Such battery use conditions may be preset in consideration of the type of battery and the use of the battery.

[0091] Preferably, the control unit 130 may change and set the battery use conditions based on the cause of the side reaction. Specifically, the control unit 130 may change and set the battery use conditions depending on the cause of loss of available lithium.

[0092] Specifically, when it is determined that the cause of the side reaction is lithium deposition, the control unit 130 may set the use conditions of the battery so that the lithium deposition reaction is suppressed. For example, when it is determined that the cause of the side reaction is lithium deposition, the control unit 130 may be configured to reduce the upper limit of the charge / discharge C rate for the battery.

[0093] In addition, when it is determined that the cause of the side reaction is an electrolyte side reaction, the control unit 130 may set the usage conditions of the battery so that the electrolyte decomposition reaction is suppressed. For example, when it is determined that the cause of the side reaction is an electrolyte side reaction, the control unit 130 may be configured to reduce the temperature and the upper limit SOC for the battery.

[0094] In addition, when the cause of the side reaction is determined to be lithium deposition and electrolyte side reaction, the control unit 130 may set the use conditions of the battery so that the lithium deposition reaction is suppressed and electrolyte decomposition on the surface of the deposited lithium metal is suppressed. For example, when the cause of the side reaction is determined to be lithium deposition and electrolyte side reaction, the control unit 130 may be configured to reduce the upper limit of the charge / discharge C rate, the temperature, and the upper limit SOC for the battery.

[0095] That is, the battery management device 100 according to an embodiment of the present invention can prevent further side reactions from occurring in the battery and can eliminate the activity of the side reactions by setting the use conditions of the battery in response to the cause of the side reactions, thereby resulting in an increased battery life. In addition, there is an advantage in that unexpected accidents such as fires and explosions can be prevented in advance.

[0096] On the other hand, the battery may be charged or discharged at a low rate. Specifically, the battery may be charged or discharged at a low C-rate condition that is lower than a preset reference C-rate.

[0097] For example, the battery may be charged or discharged at a C-rate equal to or less than a predetermined ratio of a reference C-rate. Here, assuming the reference C-rate is 1C and the predetermined ratio is 0.2, the battery may be charged or discharged at a C-rate equal to or less than 0.2C.

[0098] The reference C rate may be initially set in consideration of the BOL state of the battery, and may be changed in the process in which the control unit 130 changes the upper limit of the charge / discharge C rate.

[0099] In this way, a battery that has been low-rate charged or discharged can be a diagnosis target in which the occurrence of a side reaction can be easily determined based on the behavior of the target peak alone. Therefore, the side reaction determination unit 110 can determine that a side reaction has occurred if the voltage of the target peak exceeds the voltage of the reference peak for a battery that has been low-rate charged or discharged.

[0100] The side reaction determination unit 110, the side reaction cause determination unit 120, and the control unit 130 provided in the battery management device 100 may selectively include a processor, an ASIC (Application-Specific Integrated Circuit), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art, to execute various control logics performed in the present invention. In addition, when the control logic is embodied as software, the side reaction determination unit 110, the side reaction cause determination unit 120, and the control unit 130 may be embodied as a set of program modules. In this case, the program modules may be stored in a memory and executed by the side reaction determination unit 110, the side reaction cause determination unit 120, and the control unit 130. The memory may be provided inside or outside the side reaction determination unit 110, the side reaction cause determination unit 120, and the control unit 130, and may be connected to the side reaction determination unit 110, the side reaction cause determination unit 120, and the control unit 130 by various known means.

[0101] The battery management device 100 may further include a recording unit 140. The recording unit 140 may store data or programs required for each component of the battery management device 100 to operate and function, or data generated in the process of operating and functioning. The recording unit 140 is not particularly limited in type as long as it is a known information recording means known to be capable of recording, erasing, updating, and reading data. As an example, the information recording means may include a RAM, a flash memory, a ROM, an EEPROM, a register, and the like. The recording unit 140 may also store program code that defines processes that can be executed by each component of the battery management device 100.

[0102] For example, the recording unit 140 may store the reference profile P, the differential profile D, the reference resistance profile, and the resistance profile. The recording unit 140 may also store the use conditions preset for the battery and the use conditions changed by the control unit 130.

[0103] The battery management 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-mentioned battery management device 100. In this configuration, at least some of the components of the battery management device 100 may be implemented by complementing or adding functions of components included in a conventional BMS. For example, the side reaction determination unit 110, the side reaction cause determination unit 120, the control unit 130, and the recording unit 140 of the battery management device 100 may be implemented as components of the BMS.

[0104] The battery management device 100 according to the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the above-described battery management device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.), a case, etc.

[0105] FIG. 8 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0106] The positive terminal of the battery 10 may be connected to the positive terminal P+ of the battery pack 1, and the negative terminal of the battery 10 may be connected to the negative terminal P− of the battery pack 1.

[0107] The measurement unit 200 may be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. Specifically, the measurement unit 200 may be connected to a positive terminal of the battery 10 via the first sensing line SL1 and to a negative terminal of the battery 10 via the second sensing line SL2. The measurement unit 200 may measure the voltage of the battery 10 based on the voltages measured in the first sensing line SL1 and the second sensing line SL2, respectively.

[0108] The measurement unit 200 may be connected to the current measurement unit A through a third sensing line SL3. For example, the current measurement unit A may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 10. The measurement unit 200 may measure the charging current of the battery 10 through the third sensing line SL3 to calculate the charged amount. The measurement unit 200 may also measure the discharging current of the battery 10 through the third sensing line SL3 to calculate the discharged amount.

[0109] One end of the external device 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 the battery 10, the positive terminal P+ of the battery pack 1, the external device, the negative terminal P- of the battery pack 1, and the negative terminal of the battery 10 may be electrically connected. For example, the external device may be a charging / discharging device, or a motor of an electric vehicle that receives power from the battery 10.

[0110] 9 and 10 are diagrams illustrating a battery management method according to still another embodiment of the present invention.

[0111] Referring to FIG. 9, the battery management method may include a target peak determining step S100, a side reaction determining step S200, a resistance pattern determining step S300, and a side reaction cause determining step S400.

[0112] Preferably, each step of the battery management method may be performed by the battery management device 100. In the following, for convenience of explanation, contents that overlap with the above explanation will be omitted or will be briefly explained.

[0113] The target peak determining step S100 is a step of determining a target peak in a differential profile D indicating a correspondence relationship between a voltage and a differential capacity of a battery, and may be performed by the side reaction determining unit 110.

[0114] Specifically, the side reaction determining unit 110 can determine the peak corresponding to the lowest voltage among the multiple peaks included in the differential profile D as the target peak.

[0115] Referring to the first derivative profile D1 in FIG. 2 and FIG. 3, the side reaction determining unit 110 may determine a first target peak tp1 from a plurality of peaks included in the first derivative profile D1.

[0116] The side reaction determining step S200 is a step of determining whether a side reaction occurs in the battery by comparing a reference peak of a preset reference profile P with a target peak, and may be performed by the side reaction determining unit 110.

[0117] Specifically, the side reaction determining unit 110 may compare the voltage of the target peak of the differential profile D with the voltage of the reference peak of the reference profile P. Then, if the voltage of the target peak exceeds the voltage of the reference peak, the side reaction determining unit 110 may determine that a side reaction has occurred in the battery.

[0118] 2 and 3, the voltage of the first target peak tp1 exceeds the voltage of the first reference peak rp1, so that the side reaction determining unit 110 can determine that a side reaction has occurred in the first battery.

[0119] The resistance pattern determining step S300 is a step of determining a resistance pattern of the battery for a reference voltage section RR in a resistance profile indicating a correspondence relationship between the voltage and resistance of the battery, and may be performed by the side reaction cause determining unit 120.

[0120] Specifically, the side reaction cause determining unit 120 may determine the resistance pattern of the battery as the first resistance pattern and / or the second resistance pattern based on the change in resistance according to the voltage in the reference voltage section RR of the resistance profile.

[0121] Here, the first resistance pattern is a pattern in which the resistance decreases as the voltage increases, and the second resistance pattern is a pattern in which the resistance of the resistance profile in the reference voltage section RR is equal to or greater than the resistance of the reference resistance profile.

[0122] Referring to the first resistance profile R1 of FIG. 4, as the voltage increases in the reference voltage section RR, the resistance decreases, so that the side reaction cause determining unit 120 may determine the resistance pattern of the first battery as the first resistance pattern.

[0123] The side reaction cause determining step S400 is a step of determining the cause of the side reaction based on the determined resistance pattern, and may be performed by the side reaction cause determining unit 120.

[0124] Specifically, the side reaction cause determining unit 120 can determine that the cause of the side reaction is lithium deposition and / or an electrolyte side reaction based on the resistance pattern of the battery.

[0125] For example, if the resistance pattern of the battery is the first resistance pattern, the side reaction cause determining unit 120 may determine that the cause of the side reaction is lithium deposition.

[0126] As another example, if the resistance pattern of the battery is the second resistance pattern, the side reaction cause determining unit 120 may determine that the cause of the side reaction is an electrolyte side reaction.

[0127] As yet another example, if the resistance pattern of the battery is the first resistance pattern and the second resistance pattern, the side reaction cause determining unit 120 may determine that the cause of the side reaction is lithium deposition and an electrolyte side reaction.

[0128] Referring to FIG. 10, the battery management method may further include a use condition setting step S500 after the side reaction cause determining step S400.

[0129] The use condition setting step S500 is a step of setting the use condition of the battery based on the determined cause of the side reaction, and may be performed by the control unit 130.

[0130] Specifically, the control unit 130 may set different conditions for using the battery depending on the cause of the side reaction.

[0131] For example, the control unit 130 may be configured to reduce the upper limit of the charge / discharge C-rate for the battery if the cause of the side reaction is determined to be lithium deposition.

[0132] As another example, the control unit 130 may be configured to reduce the temperature and upper SOC limit for the battery when the cause of the side reaction is determined to be an electrolyte side reaction.

[0133] As yet another example, the control unit 130 may be configured to reduce the upper limit of the charge / discharge C rate, the temperature, and the upper limit SOC for the battery when the cause of the side reaction is determined to be lithium deposition and electrolyte side reaction.

[0134] The above-described embodiments of the present invention may be embodied not only by an apparatus and a method, but also through 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 implementation can be easily implemented by a person skilled in the art from the description of the above-described embodiments.

[0135] As described above, the present invention has been described using limited embodiments and drawings. However, 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 belongs within the technical spirit of the present invention and the equivalent scope of the claims.

[0136] Furthermore, the present invention described above is susceptible to various substitutions, modifications and alterations 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 may be configured by selectively combining all or part of each embodiment for various modifications. [Explanation of symbols]

[0137] 1: Battery pack 100: Battery management device 110: Side effect determination unit 120: Side effect cause determination section 130: Control unit 140: Recording section 200: Measuring part

Claims

1. a side reaction determination unit configured to determine a target peak in a differential profile showing a correspondence relationship between a voltage and a differential capacity of a battery, and to determine whether a side reaction has occurred in the battery by comparing a reference peak of a preset reference profile with the target peak; a side reaction cause determination unit configured to determine a resistance pattern of the battery for a reference voltage section using a resistance profile indicating a correspondence relationship between the voltage and resistance of the battery, and to determine a cause of the side reaction based on the determined resistance pattern.

2. The side reaction cause determination unit The battery management device according to claim 1 , further comprising: determining a cause of the side reaction to be at least one of lithium precipitation and an electrolyte side reaction based on the determined resistance pattern.

3. The side reaction cause determination unit The battery management device according to claim 2 , configured to determine a first resistance pattern when the resistance decreases as the voltage increases in the reference voltage section of the resistance profile.

4. The side reaction cause determination unit The battery management device according to claim 3 , further comprising: a step of: determining that the cause of the side reaction is the lithium deposition when the determined resistance pattern is the first resistance pattern.

5. The side reaction cause determination unit 3 . The battery management device according to claim 2 , further comprising: a second resistance pattern determined when a resistance of the resistance profile is equal to or greater than a resistance of a preset reference resistance profile in the reference voltage section of the resistance profile.

6. The side reaction cause determination unit The battery management device according to claim 5 , further configured to determine that a cause of the side reaction is the electrolyte side reaction when the determined resistance pattern is the second resistance pattern.

7. The battery management device according to claim 2 , further comprising a control unit configured to set a usage condition of the battery based on the determined cause of the side reaction.

8. The control unit is When it is determined that the cause of the side reaction is the lithium deposition, an upper limit of a charge / discharge C rate for the battery is reduced; The battery management device of claim 7 , configured to reduce a temperature and an upper limit SOC for the battery if the cause of the side reaction is determined to be the electrolyte side reaction.

9. The side reaction determination unit The battery management device according to claim 1 , configured to determine whether a side reaction occurs in the battery by comparing the target peak voltage with the reference peak voltage.

10. The side reaction determination unit 10. The battery management device of claim 9, configured to determine that the side reaction has occurred if the voltage of the target peak exceeds the voltage of the reference peak.

11. The reference voltage section is 2. The battery management device according to claim 1, wherein the preset reference resistance profile is configured as a voltage section including a resistance from a minimum resistance to a resistance equal to or lower than a predetermined critical resistance.

12. A battery pack comprising a battery management device according to any one of claims 1 to 11.

13. A target peak determination step of determining a target peak in a differential profile showing a correspondence relationship between the voltage and the differential capacity of the battery; determining whether a side reaction has occurred in the battery by comparing a reference peak of a preset reference profile with the target peak; determining a resistance pattern of the battery for a reference voltage section in a resistance profile indicating a correspondence relationship between the voltage and resistance of the battery; determining a cause of the side reaction based on the determined resistance pattern.

14. The battery management method of claim 13, further comprising, after the determining step of determining the cause of the side reaction, setting a use condition of the battery based on the determined cause of the side reaction.

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