Battery management system, battery pack, electric vehicle and battery management method

Abstract

A battery management system according to the present invention comprises: a first temperature sensor that generates a first temperature signal representing a measured value of the battery temperature, which is the temperature of the battery; a second temperature sensor that generates a second temperature signal representing a measured value of the external temperature; a memory that stores a first reference map; and a control unit that collects the first temperature signal and the second temperature signal. The control unit determines a first change amount of the battery temperature, a first charging time, and a first average external temperature at predetermined intervals while the first charging stage of the battery is in progress, and using the first reference map, determines a first reference change amount of the battery temperature based on a first starting temperature, the first charging time, and the first average external temperature, and compares the first change amount with the first reference change amount to determine whether the battery is faulty.

Description

Technology Field

[0001] The present invention relates to a technology for monitoring the temperature of a battery. Background Technology

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance batteries capable of repeated charging and discharging is actively underway.

[0004] Currently commercialized batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium batteries. Among these, lithium batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0005] A significant amount of energy is stored in batteries, and as the battery temperature rises, the risk of fire and explosion increases. Therefore, it is necessary to continuously monitor the battery temperature and take appropriate measures to prevent overheating.

[0006] The causes of abnormal temperature behavior in a battery during charging can be broadly classified into three categories. The first cause is excessive charging voltage and / or charging current, the second cause is the external temperature of the battery, and the third cause is battery failure. Battery failure includes so-called self-heating abnormalities, where the battery generates heat on its own due to adverse reactions or defects (e.g., internal short circuits) occurring internally.

[0007] Abnormal temperature behavior caused by the first and second causes can be suppressed by appropriately reducing the charging voltage and / or charging current, stopping battery charging, or supplying sufficient cooling medium to the battery. However, since the third cause depends on the internal state of the battery, it is difficult to resolve without replacing the battery.

[0008] Conventionally, monitoring is limited to whether the battery temperature exceeds a preset upper limit during charging, and it is impossible to distinguish whether the abnormal temperature behavior of the battery is due to a malfunction.

[0009] For example, in environments where the external temperature is much lower than the actual battery temperature, the battery cools rapidly due to thermal convection. Consequently, even if the battery exhibits self-heating abnormalities, the temperature rise during charging is minimal or may even decrease, making it difficult to identify the fault. As another example, when the external temperature is higher than the actual battery temperature, it is difficult to determine whether self-heating contributed to the temperature increase. The problem to be solved

[0011] The present invention is devised to solve the above-mentioned problems and aims to provide a battery management system, a battery pack, an electric vehicle, and a battery monitoring method capable of identifying battery failures that cause abnormal temperature behavior due to self-heating abnormalities by monitoring the time-series changes of the battery temperature and the external temperature, respectively, during battery charging.

[0012] Other objects and advantages of the present invention may be understood from the following description and will become more clearly apparent from the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0014] A battery management system according to one aspect of the present invention comprises: a first temperature sensor configured to generate a first temperature signal representing a measured value of the battery temperature, which is the temperature of the battery; a second temperature sensor configured to generate a second temperature signal representing a measured value of the external temperature; a memory configured to store a first reference map; and a control unit configured to collect the first temperature signal and the second temperature signal. The control unit is configured to determine, at every predetermined time interval while the first charging stage of the battery is in progress, a first change amount of the battery temperature, a first charging time, and a first average external temperature, and to determine a first reference change amount of the battery temperature based on a first starting temperature, the first charging time, and the first average external temperature using the first reference map, and to determine whether the battery is faulty by comparing the first change amount with the first reference change amount. The first starting temperature is the battery temperature obtained at the start of the first charging stage.

[0015] The control unit may be configured to determine the first change amount by subtracting the first starting temperature from the battery temperature obtained at the current point in time during the progress of the first charging stage.

[0016] The control unit may be configured to determine the first average external temperature by averaging the time series of the external temperature measurements taken at the predetermined time intervals over the first charging time.

[0017] The control unit may be configured to determine that the battery is faulty when the first change amount is detected to be greater than or equal to the reference difference value of the first reference change amount for one or two or more consecutive reference counts.

[0018] The first reference map may be a lookup table or function that provides a correlation between the first starting temperature, the first charging time, the first average external temperature, and the first reference change amount.

[0019] The memory may be configured to store a second reference map. The control unit may be configured to determine a second change amount of the battery temperature, a second charging time, and a second average external temperature at predetermined intervals while the second charging stage is in progress, and to determine a second reference change amount of the battery temperature based on the second starting temperature, the second charging time, and the second average external temperature using the second reference map, wherein the second starting temperature is the battery temperature obtained at the start of the second charging stage, and to determine whether the battery is faulty by comparing the second change amount with the second reference change amount.

[0020] The battery management system may further include a voltage sensor configured to generate a voltage signal representing a measured value of the battery voltage, which is a voltage across both ends of the battery. The first charging stage may be a constant current charging stage, and the second charging stage may be a constant voltage charging stage. The control unit may be configured to identify that the system has switched from the first charging stage to the second charging stage in response to the battery voltage reaching a predetermined cutoff voltage during the progress of the first charging stage.

[0021] The control unit may be configured to determine that the battery is faulty when the second change amount is detected to be greater than or equal to the reference difference value of the second reference change amount for one or two or more consecutive reference counts.

[0022] The control unit may be configured to determine that the battery is faulty when the sum of the final value of the first change amount and the second change amount is greater than the reference difference value for one or two or more consecutive reference counts.

[0023] A battery pack according to another aspect of the present invention includes the battery management system.

[0024] An electric vehicle according to another aspect of the present invention includes the battery pack.

[0025] A battery management method according to another aspect of the present invention may be executed at predetermined intervals by the battery management system. The battery management method comprises: a step of determining a first change amount of the battery temperature, a first charging time, and a first average external temperature when a first charging stage of the battery is in progress; a step of determining a first reference change amount of the battery temperature based on a first starting temperature, the first charging time, and the first average external temperature using the first reference map, wherein the first starting temperature is the battery temperature obtained at the start of the first charging stage; and a step of determining whether the battery is faulty by comparing the first change amount with the first reference change amount. Effects of the invention

[0027] According to at least one of the embodiments of the present invention, by monitoring the time-series changes of the battery temperature and the external temperature, respectively, during the charging of the battery, it is possible to identify a battery failure that causes abnormal temperature behavior due to self-heating abnormalities.

[0028] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention in an exemplary manner. Figure 2 is an exemplary graph referenced to explain the relationship between battery temperature and external temperature during charging of a normal battery. Figure 3 is an exemplary graph referenced to explain the relationship between battery temperature and external temperature during charging of a faulty battery. FIG. 4 is a flowchart exemplarily illustrating a battery management method according to a first embodiment of the present invention. FIG. 5 is a flowchart illustrating an exemplary battery management method according to a second embodiment of the present invention. FIG. 6 is a flowchart illustrating an exemplary battery management method according to a third embodiment of the present invention. Specific details for implementing the invention

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0032] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0033] Terms including ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms.

[0034] Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "part (unit)" as used in the specification refer to a unit that performs at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

[0035] Additionally, throughout the specification, when it is said that a part is "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other components in between.

[0036] FIG. 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention in an exemplary manner.

[0037] Referring to FIG. 1, the electric vehicle (1) includes a vehicle controller (2), a battery pack (10), a relay (20), an inverter (30), and an electric motor (40). The charging and discharging terminals (P+, P-) of the battery pack (10) can be electrically connected to a charger (3) via a charging cable or the like. The charger (3) may be included in the electric vehicle (1) or provided at a charging station.

[0038] A vehicle controller (2) (e.g., ECU: Electronic Control Unit) is configured to transmit a key-on signal to a battery management system (100) in response to a user switching a start button (not shown) provided in an electric vehicle (1) to the ON position. The vehicle controller (2) is configured to transmit a key-off signal to a battery management system (100) in response to a user switching a start button to the OFF position. A charger (3) can communicate with the vehicle controller (2) to supply charging power of a constant current or constant voltage through the charging / discharging terminals (P+, P-) of the battery pack (10). The charger (3) may have a discharge function and, prior to initiating the first charging stage (S1) described below, may discharge the battery (11) so that the battery voltage (e.g., OCV) of the battery (11) becomes below a predetermined reference voltage upon a request from the vehicle controller (2).

[0039] The battery pack (10) includes a battery (11) and a battery management system (100).

[0040] The battery (11) includes a cell group (12) and a case (13). The case (13) defines the overall shape of the battery (11) and provides an internal space where the cell group (12) can be placed. The case (13) is fixedly fastened to a battery room provided in the electric vehicle (1) using bolts or the like.

[0041] The cell group (12) includes at least one battery cell (BC) that is placed (stored) in the internal space provided by the case (13). The type of the battery cell (BC) is not particularly limited, provided that it is capable of repeated charging and discharging, such as a lithium-ion cell.

[0042] When a cell group (12) has multiple battery cells, the multiple battery cells can be connected in series, parallel, or a combination of series and parallel.

[0043] The relay (20) is electrically connected in series to the battery (11) through a power path connecting the battery (11) and the inverter (30). In FIG. 1, the relay (20) is illustrated as being connected between the positive terminal and the charge / discharge terminal (P+) of the battery (11). The relay (20) is turned on / off in response to a switching signal from the battery management system (100). The relay (20) may be a mechanical contactor that is turned on / off by the magnetic force of a coil, or a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0044] An inverter (30) is provided to convert direct current from a cell group (12) into alternating current in response to a command from a battery management system (100) or a vehicle controller (2).

[0045] The electric motor (40) is driven using alternating current power from the inverter (30). For example, a three-phase alternating current motor (40) can be used as the electric motor (40).

[0046] The battery management system (100) includes a temperature sensor (110), a temperature sensor (120), and a control unit (150). The battery management system (100) may further include at least one of a voltage sensor (130), a current sensor (140), and a communication circuit (160). Hereinafter, the battery management system (100) will be described assuming that it includes all of the voltage sensor (130), the current sensor (140), and the communication circuit (160).

[0047] A temperature sensor (110) is configured to measure the battery temperature, which is the temperature of the battery (11), and to generate a temperature signal indicating the measured battery temperature. The temperature sensor (110) may be placed within a case (13) so as to measure a temperature close to the actual temperature of the battery (11). For example, the temperature sensor (110) may be attached to the surface of at least one battery cell (BC) included in a cell group (12) and may detect the surface temperature of the battery cell (BC) as the battery temperature.

[0048] The temperature sensor (120) is configured to measure an external temperature (ambient temperature) which is the temperature at a predetermined location spaced apart from the battery (11), and to generate a temperature signal indicating the measured external temperature. The temperature sensor (120) may be placed at a predetermined location outside the case (13) where heat exchange between the battery (11) and the atmosphere takes place.

[0049] Each of the temperature sensor (110) and the temperature sensor (120) can be implemented as one or more combinations of known temperature detection elements such as thermocouples, thermistors, bimetals, etc.

[0050] A voltage sensor (130) is connected in parallel to the battery (11) to measure the battery voltage, which is the voltage across both ends of the battery (11), and is configured to generate a voltage signal indicating the measured battery voltage.

[0051] A current sensor (140) is connected in series to the battery (11) through a current path between the battery (11) and the inverter (30). The current sensor (140) is configured to measure the battery current, which is the current flowing through the battery (11), and to generate a current signal representing the measured battery current. The current sensor (140) may be implemented as one or more combinations of known current detection elements, such as a shunt resistor, a Hall effect element, etc.

[0052] The communication circuit (160) is configured to support wired or wireless communication between the control unit (150) and the vehicle controller (2). Wired communication may be, for example, CAN (controller area network) communication, and wireless communication may be, for example, Zigbee or Bluetooth communication. Of course, as long as it supports wired or wireless communication between the control unit (150) and the vehicle controller (2), the type of communication protocol is not particularly limited. The communication circuit (160) may include an output device (e.g., display, speaker) that provides information received from the control unit (150) and / or the vehicle controller (2) in a form recognizable by the user.

[0053] The control unit (150) is operably coupled to the relay (20), temperature sensor (110), temperature sensor (120), voltage sensor (130), current sensor (140), and communication circuit (160). Being operably coupled to the two components means that the two components are directly or indirectly connected so that signals can be transmitted and received in either a unidirectional or bidirectional manner.

[0054] The control unit (150) can collect a temperature signal from the temperature sensor (110), a temperature signal from the temperature sensor (120), a voltage signal from the voltage sensor (130), and / or a current signal from the current sensor (140). The control unit (150) can convert and record each analog signal collected from the sensors (110, 120, 130, 140) into a digital value using an internally provided ADC (Analog to Digital Converter).

[0055] The control unit (150) may be referred to as a 'control circuit' or 'battery controller' and may be implemented in hardware using at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors, and other electrical units for performing functions.

[0056] The memory (151) may include at least one type of storage medium among, for example, a flash memory type, a hard disk type, an SSD type (Solid State Disk type), an SSD type (Silicon Disk Drive type), a multimedia card micro type, RAM (random access memory; RAM), SRAM (static random access memory), ROM (read-only memory; ROM), EEPROM (electrically erasable programmable read-only memory), and PROM (programmable read-only memory). The memory (151) may store data and programs required for operation by the control unit (150). The memory (151) may store data representing the result of operation by the control unit (150). The memory (151) may store a first reference map used to detect a failure of the battery (11) being charged, and may further store a second reference map.

[0057] The control unit (150) can turn on the relay (20) in response to a key-on signal. The control unit (150) can turn off the relay (20) in response to a key-off signal. The key-off signal indicates a transition from an active state to an idle state. Alternatively, the on / off control of the relay (20) can be handled by the vehicle controller (2) instead of the control unit (150).

[0058] While the relay (20) is turned on, the battery (11) is in a working state. Conversely, while the relay (20) is turned off, the battery (11) is in a resting state. The working state is a state in which the battery (11) is being charged and discharged, and may also be referred to as the 'cycle state'. The resting state is a state in which the charging and discharging of the battery (11) has stopped, and may also be referred to as the 'calendar state'.

[0059] The control unit (150) can determine the State of Charge (SOC) of the battery (11) based on voltage and current signals while the battery (11) is in use. The SOC is the ratio of the remaining capacity to the full charge capacity of the battery (11), and is typically processed in the range of 0 to 1 or 0 to 100%. Known methods such as ampere counting, OCV (Open Circuit Voltage)-SOC curves and / or Kalman filters may be utilized to determine the SOC.

[0060] The control unit (150) can perform operations to detect an abnormal self-heating of the battery (11) while the battery (11) is being charged.

[0061] FIG. 2 is an exemplary graph referenced to explain the relationship between battery temperature and external temperature during charging of a normal battery. The curves (211, 212, 221, 222, 231, 232) associated with battery temperature shown in FIG. 2 were obtained as a result of performing tests using various temperature conditions on sample batteries manufactured to have the same specifications and electrochemical characteristics as battery (11).

[0062] Referring to FIG. 2, the charging procedure for the battery (11) may include a first charging stage (S1) and a second charging stage (S2).

[0063] <1st Charging Stage>

[0064] The first charging stage (S1) has a charging current (I) of a predetermined current rate (which may be referred to as 'C-rate'). C This is a stage in which constant current charging is performed. The first charging stage (S1) can be performed from when the battery voltage of the battery (11) is below a predetermined reference voltage until it reaches a predetermined cutoff voltage.

[0065] In Fig. 2, at time t A is the point in time when the first charging stage (S1) starts with the open circuit voltage (OCV) of the normal battery adjusted to be equal to the reference voltage. In FIG. 2, time t B t is the point in time when the battery voltage of the normal battery reaches the cutoff voltage during the execution of the first charging stage (S1). B In this step, the charging procedure transitions from the first charging stage (S1) to the second charging stage (S2). The curve (201) represents the charging current (I) in the first charging stage (S1). C It indicates that ) is maintained at a constant level.

[0066] The curve (211) is at time t AFor a normal battery at a battery temperature of T1 (e.g., 25 ℃), at a predetermined temperature lower than T1 (T X The change in battery temperature obtained by performing the first charging stage (S1) while maintaining a constant external temperature (e.g., 10 ℃) is exemplified. In the curve (211), the battery temperature decreases from T1 due to natural cooling in the initial part of the first charging stage (S1), and then at time t, as the amount of heat generated by charging exceeds the amount of heat dissipated by natural cooling B You can see that the battery temperature is rising.

[0067] The curve (221) is at time t A For a normal battery at a battery temperature of T1, a predetermined temperature (T) higher than T1 Y The change in battery temperature obtained by performing the first charging stage (S1) while maintaining a constant external temperature (e.g., 50 ℃) is exemplified. In contrast to curve (211), in curve (221), from the beginning of the first charging stage (S1) at time t B It can be observed that the battery temperature continues to rise until.

[0068] The curve (231) is at time t A For a normal battery at a battery temperature of T2 (e.g., 35 ℃), at a predetermined temperature higher than T2 (T Y The change in battery temperature obtained by performing the first charging stage (S1) while maintaining the external temperature constant is exemplified. Comparing curve (221) with curve (231), from the beginning of the first charging stage (S1) to time t B It is common that the battery temperature continues to rise until. However, even if the external temperature is the same, at time t A If the battery temperature is different, it can be confirmed that the behavior of the change in battery temperature in the first charging stage (S1) is different.

[0069] The inventors, from the results of a plurality of tests performed to obtain the curves (211, 221, 231) described above with reference to FIG. 2, find that the amount of change in battery temperature in the first charging stage (S1) is (i) at the start time t of the second charging stage (S2). A Battery temperature at (first starting temperature), (ii) starting time t A It was confirmed that there is a correlation depending on the time elapsed from (first charging time) and (ii) the average of the external temperature over the first charging stage (S1) (first average external temperature). The amount of change in battery temperature in the first charging stage (S1) represents the value obtained by subtracting the starting temperature from the battery temperature at any point in time during the first charging stage (S1).

[0070] Accordingly, a lookup table or function providing a correlation between the starting temperature, charging time, average external temperature, and reference change amount associated with the first charging stage (S1) may be stored in advance in the memory (151) of the control unit (150). The reference change amount represents the change amount of the battery temperature when the battery (11) is normal.

[0071] <2nd Charging Stage>

[0072] The second charging stage (S2) is a stage in which constant voltage charging is performed by a cutoff voltage. The second charging stage (S2) is performed when the battery voltage of the battery (11) reaches the cutoff voltage (time t). B From ), the battery current becomes a predetermined cutoff current (I E When reaching ) (time t C It can be performed up to ). Of course, cutoff current (I E ) is the charging current (I C It is smaller than ). In the second charging stage (S2), the battery current is smaller than the cutoff current (I E It continuously decreases toward ).

[0073] The curve (212) is a portion continuous to the curve (211), and has a predetermined temperature (T X The change in battery temperature obtained by performing the second charging stage (S2) while maintaining the external temperature constant is exemplified. In the curve (212), at time t B At battery temperature and external temperature (T X Since the difference between ) is considerably large and the amount of heat generated by the battery current is smaller than the amount of heat generated in the first charging stage (S1), the battery temperature is at time t B From the temperature and external temperature (T X You can see it rapidly descending toward ).

[0074] The curve (222) is a portion continuous to the curve (221), and has a predetermined temperature (T Y The change in battery temperature obtained by performing the second charging stage (S2) while maintaining the external temperature constant is exemplified. In the curve (222), at time t B The battery temperature at the external temperature (T Y Since the battery temperature is higher than ), the temperature at time t B From the temperature and external temperature (T Y It can be confirmed that it is similar to the curve (212) in that it descends toward ). However, the point in time t according to the curve (222) B Since the difference between the battery temperature and the external temperature is smaller than curve (212), curve (222) descends more gently than curve (212).

[0075] The curve (232) is a portion continuous to the curve (231), and has a predetermined temperature (T Y The change in battery temperature obtained by performing the second charging stage (S2) while maintaining the external temperature constant is exemplified. In the curve (232), at time t B The battery temperature at the external temperature (T Y Since the battery temperature is higher than ), the temperature at time t B From the temperature and external temperature (T YIt can be confirmed that it is similar to the curve (222) in that it descends toward ). However, at time t B Since the difference between the battery temperature and the external temperature is greater in curve (232) than in curve (222), curve (232) is descending faster than curve (222).

[0076] The inventors, from the results of a plurality of tests performed to obtain the curves (212, 222, 232) described above with reference to FIG. 2, find that the amount of change in battery temperature in the second charging stage (S2) is (i) at the start time t of the second charging stage (S2). B Battery temperature at (second starting temperature), (ii) starting time t B It was confirmed that there is a correlation depending on the time elapsed from (second charging time) and (ii) the average of the external temperature over the second charging stage (S2) (second average external temperature). The amount of change in battery temperature in the second charging stage (S2) represents the value obtained by subtracting the first starting temperature or the second starting temperature from the battery temperature at any point in the second charging stage (S2).

[0077] Accordingly, a lookup table or function providing a correlation between the starting temperature, charging time, average external temperature, and reference change amount associated with the second charging stage (S2) may be stored in advance in the memory (151) of the control unit (150). The reference change amount represents the change amount of the battery temperature when the battery (12) is normal.

[0078] FIG. 3 is an exemplary graph referenced to explain the relationship between the battery temperature and the external temperature during the charging of a faulty battery. The curves (211, 212) shown in FIG. 3 are identical to the curves (211, 212) shown in FIG. 2. For convenience of explanation, the external temperature is T over the entire charging process. X It is assumed to be constant.

[0079] In FIG. 3, the curve (301) is at time t A For a faulty battery with a battery temperature of T1 at the external temperature (T X The change in battery temperature of a faulty battery obtained by performing the first charging stage (S1) while maintaining ) constant is exemplified. The curve (302) is a part continuous to the curve (301), and the external temperature (T X The change in battery temperature of the faulty battery obtained by performing the second charging stage (S2) while maintaining ) at a constant is exemplified.

[0080] First, regarding the first charging stage (S1), unlike the curve (211) of the normal battery, the battery temperature according to the curve (301) of the faulty battery shows no or very small temperature drop in the early part of the first charging stage (S1). Additionally, it can be confirmed that the battery temperature of the faulty battery is higher than the battery temperature of the normal battery throughout the first charging stage (S1), and the difference between the two tends to increase as the first charging stage (S1) progresses.

[0081] Next, with respect to the second charging stage (S2), at time t B At, the battery temperature (T of the faulty battery F ) and external temperature (T X The difference between ) is the battery temperature of a normal battery (T N ) and external temperature (T X It is greater than the difference between ). If, time t B At T F In the case of the ramen, the battery temperature of the normal battery follows the curve (310) and the external temperature (T X It descends faster than the curve (212) toward ).

[0082] On the other hand, in the case of a faulty battery, the temperature rise due to self-heating is relative to the external temperature (T XBecause natural cooling by means of) is hindered, the rate of temperature decrease may be slow, such as with curve (302) rather than curve (310), or the battery temperature may even rise.

[0083] FIG. 4 is a flowchart illustrating an exemplary battery management method according to a first embodiment of the present invention. The method of FIG. 4 can be executed by a battery management system (100) when the first charging stage (S1) of the battery (11) is initiated.

[0084] Referring to FIGS. 1 to 4, in step S410, the control unit (150) determines the battery temperature and the external temperature based on the first temperature signal and the second temperature signal. That is, the control unit (150) acquires the measured values ​​of the battery temperature and the external temperature at predetermined intervals and records them in the memory (151).

[0085] In step S420, the control unit (150) determines a first change amount of battery temperature, a first charging time, and a first average external temperature. The first change amount is determined by subtracting a first starting temperature from the battery temperature obtained at the current time. The first starting temperature is the starting time of the first charging stage (t A It is the battery temperature obtained at ). The first charging time is the start time (t) from the current time. A It is determined by subtracting ). The first average external temperature is, at the start time (t A It is determined by averaging the time series of external temperature measurements determined during the period from ) to the present time.

[0086] In step S430, the control unit (150) determines a first reference change amount of the battery temperature based on a first starting temperature, a first charging time, and a first average external temperature using a first reference map stored in memory (151). The first reference map is a lookup table or function that provides a correlation between the first starting temperature, the first charging time, the first average external temperature, and the first reference change amount. The first reference change amount is a predetermined value as the temperature change amount of the normal battery when the normal battery at the first starting temperature is charged with constant current for a first charging time under atmospheric conditions identical to the first average external temperature. Since the method of FIG. 4 is executed repeatedly at predetermined intervals, those skilled in the art will easily understand that the first charging time, the first average external temperature, and the first reference change amount will also be updated at predetermined intervals.

[0087] In step S440, the control unit (150) determines whether the first change amount is greater than or equal to the reference difference value than the first reference change amount. The reference difference value may be stored in advance in memory (151) to determine whether the battery (11) is faulty. If the value of step S440 is "yes," step S452 or step S470 may proceed. If the value of step S440 is "no," step S454 may proceed.

[0088] In step S452, the control unit (150) increases the first fault count by 1.

[0089] In step S454, the control unit (150) resets the first fault count or decreases it by 1. When the reset is executed, the first fault count can be set to 0.

[0090] In step S460, the control unit (150) determines whether the first failure count is greater than or equal to the reference count. If step S460 is "Yes," it indicates that the first change amount is greater than the reference difference value than the first reference change amount, and that the reference count has been detected continuously, i.e., the battery (11) is faulty. Two or more reference counts may be stored in advance in the memory (151). If the value of step S460 is "Yes," step S470 may proceed.

[0091] In step S470, the control unit (150) executes a predetermined protection function(s). For example, the control unit (150) may output an alarm message indicating that the battery (11) is faulty to the vehicle controller (2) and / or the driver through the communication circuit (160). For another example, the control unit (150) may execute safety function(s), such as sending a request to stop charging to the vehicle controller (2) or turning off the relay (20), in response to the determination that the battery (11) is faulty.

[0092] FIG. 5 is a flowchart illustrating a battery management method according to a second embodiment of the present invention. The method of FIG. 5 can be executed by a battery management system (100) when a second charging stage (S2) of a battery (11) is initiated. A control unit (150) can acquire a measured value of the battery voltage of the battery (11) based on a voltage signal collected from a voltage sensor (130), and can identify a transition from the second charging stage (S1) to the second charging stage (S2) in response to the battery voltage reaching a cutoff voltage.

[0093] Referring to FIGS. 1 to 5, in step S510, the control unit (150) determines the battery temperature and the external temperature based on the first temperature signal and the second temperature signal.

[0094] In step S520, the control unit (150) determines a second change amount of battery temperature, a second charging time, and a second average external temperature. The second change amount is determined by subtracting the second starting temperature from the battery temperature obtained at the current time. The second starting temperature is the starting time of the second charging stage (t B It is the battery temperature obtained at ). The second charging time is the start time (t) from the current time. B It is determined by subtracting ). The second average external temperature is, at the start time (t B It is determined by averaging the time series of external temperature measurements determined during the period from ) to the present time.

[0095] In step S530, the control unit (150) determines a second reference change amount of the battery temperature based on a second starting temperature, a second charging time, and a second average external temperature using a second reference map stored in memory (151). The second reference map is a lookup table or function that provides a correlation between the second starting temperature, the second charging time, the second average external temperature, and the second reference change amount. The second reference change amount is a predetermined value as the temperature change amount of the normal battery when the normal battery at the second starting temperature is charged at a constant voltage for a second charging time under atmospheric conditions identical to the second average external temperature. Since the method of FIG. 5 is executed repeatedly at predetermined intervals, those skilled in the art will easily understand that the second charging time, the second average external temperature, and the second reference change amount will also be updated at predetermined intervals.

[0096] In step S540, the control unit (150) determines whether the second change amount is greater than the second reference change amount by more than the reference difference value. If the value of step S540 is "yes," step S552 or step S570 may proceed. If the value of step S540 is "no," step S554 may proceed.

[0097] In step S552, the control unit (150) increases the second fault count by 1.

[0098] In step S554, the control unit (150) resets the second fault count or decreases it by 1.

[0099] In step S560, the control unit (150) determines whether the second failure count is greater than or equal to the reference count. If step S560 is "Yes," it indicates that the second change amount is greater than the reference difference value than the second reference change amount, and that the reference count has been detected continuously, i.e., the battery (11) is faulty. If the value of step S560 is "Yes," step S570 may proceed.

[0100] In step S570, the control unit (150) executes a predetermined protection function(s) (see step S470).

[0101] FIG. 6 is a flowchart exemplarily illustrating a battery management method according to a third embodiment of the present invention. The method of FIG. 6 can be executed by a battery management system (100) when the second charging stage (S2) of the battery (11) is initiated, similar to the method of FIG. 5. For example, at the start time (t) of the second charging stage (S2) B In the case where the first failure count is 1 or more, the method of Fig. 6 may be executed instead of the method of Fig. 5.

[0102] Referring to FIGS. 1 to 4 and FIG. 6, in step S610, the control unit (150) determines the battery temperature and the external temperature based on the first temperature signal and the second temperature signal.

[0103] In step S620, the control unit (150) determines a second change amount of battery temperature, a second charging time, and a second average external temperature.

[0104] In step S630, the control unit (150) determines a second reference change amount of the battery temperature based on a second starting temperature, a second charging time, and a second average external temperature using a second reference map stored in memory (151).

[0105] Steps S620 and S630 are common to the aforementioned steps S520 and S530, so a repeated description is omitted.

[0106] In step S640, the control unit (150) determines whether the sum of the final value of the first change amount and the second change amount is greater than or equal to the reference difference value than the sum of the final value of the first reference change amount and the second reference change amount. The final value of the first change amount is the latest first change amount determined in step S420 according to the method of FIG. 4 before transitioning from the first charging stage (S1) to the second charging stage (S2). That is, the final value of the first change amount is at time t A From time t B It is the total amount of change in battery temperature over the period up to. The final value of the first reference change amount is the latest first reference change amount determined in step S440 according to the method of FIG. 4 before transitioning from the first charging stage (S1) to the second charging stage (S2). If the value of step S640 is "Yes", step S652 may proceed. If the value of step S640 is "No", step S654 may proceed.

[0107] In step S652, the control unit (150) increases the second fault count by 1.

[0108] In step S654, the control unit (150) resets the second fault count or decreases it by 1.

[0109] In step S660, the control unit (150) determines whether the sum of the first failure count and the second failure count is greater than or equal to a reference count. If step S660 is "Yes," it indicates that the battery (11) is faulty. If the value of step S660 is "Yes," step S670 may proceed.

[0110] In step S670, the control unit (150) executes a predetermined protection function(s) (see step S470).

[0111] The embodiments of the present invention described above are not limited to implementation through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which such a program is recorded. Such implementation can be easily achieved by a person skilled in the art to which the present invention pertains, based on the description of the embodiments described above.

[0112] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0113] Furthermore, since the present invention described above allows for various substitutions, modifications, and changes within the scope of the technical concept of the present invention to those skilled in the art without departing from the technical spirit of the present invention, it is not limited by the aforementioned embodiments and attached drawings, but rather all or part of each embodiment may be selectively combined to allow for various modifications. Explanation of the symbols

[0115] 1: Electric vehicle 2: Vehicle controller 10: Battery pack 11: Battery 20: Relay 30: Inverter 40: Electric motor 100: Battery Management System 110, 120: Temperature sensor 130: Voltage sensor 150: Control unit 151: Memory 160: Communication circuit

Claims

Claim 1 A battery management system comprising: a first temperature sensor configured to generate a first temperature signal representing a measured value of the battery temperature, which is the temperature of the battery; a second temperature sensor configured to generate a second temperature signal representing a measured value of the external temperature; a memory configured to store a first reference map; and a control unit configured to collect the first temperature signal and the second temperature signal, wherein the control unit determines a first change amount of the battery temperature, a first charging time, and a first average external temperature at predetermined times while the first charging stage of the battery is in progress, and determines a first reference change amount of the battery temperature based on a first starting temperature, the first charging time, and the first average external temperature using the first reference map, wherein the first starting temperature is the battery temperature obtained at the start of the first charging stage, and determines whether the battery is faulty by comparing the first change amount with the first reference change amount. Claim 2 A battery management system according to claim 1, wherein the control unit is configured to determine the first change amount by subtracting the first starting temperature from the battery temperature obtained at the current point in time during the progress of the first charging stage. Claim 3 A battery management system according to paragraph 2, wherein the control unit is configured to determine the first average external temperature by averaging the time series of the external temperature measurements taken at the predetermined time intervals over the first charging time. Claim 4 A battery management system according to claim 1, wherein the control unit is configured to increase a first fault count by 1 when the first change amount is greater than or equal to a reference difference value than the first reference change amount, and to determine that the battery is faulty when the first fault count is greater than or equal to a reference count. Claim 5 A battery management system according to claim 1, wherein the first reference map is a lookup table or function that provides a correlation between the first starting temperature, the first charging time, the first average external temperature, and the first reference change amount. Claim 6 A battery management system according to claim 1, wherein the memory is configured to store a second reference map, and after transitioning from the first charging stage to the second charging stage, the control unit determines a second change amount of the battery temperature, a second charging time, and a second average external temperature at predetermined intervals while the second charging stage is in progress, and using the second reference map, determines a second reference change amount of the battery temperature based on the second starting temperature, the second charging time, and the second average external temperature, wherein the second starting temperature is the battery temperature obtained at the start of the second charging stage, and is configured to determine whether the battery is faulty by comparing the second change amount with the second reference change amount. Claim 7 A battery management system according to claim 6, further comprising a voltage sensor configured to generate a voltage signal representing a measured value of a battery voltage across both ends of the battery, wherein the first charging stage is a constant current charging stage and the second charging stage is a constant voltage charging stage, and the control unit is configured to identify that the battery voltage has reached a predetermined cutoff voltage during the progress of the first charging stage has been switched from the first charging stage to the second charging stage. Claim 8 A battery management system according to claim 6, wherein the control unit is configured to increase the second failure count by 1 when the second change amount is greater than or equal to the reference difference value of the second reference change amount, and to determine that the battery is faulty when the second failure count is greater than or equal to the reference count. Claim 9 A battery management system according to claim 6, wherein the control unit is configured to increase a second fault count by 1 when the sum of the final value of the first change amount and the second change amount is greater than or equal to the reference difference value of the final value of the first reference change amount and the second reference change amount, and to determine that the battery is faulty when the second fault count is greater than or equal to the reference count. Claim 10 A battery pack comprising the battery management system according to any one of claims 1 to 9. Claim 11 An electric vehicle comprising the above battery pack according to Clause 10. Claim 12 A battery management method executed at predetermined intervals by a battery management system according to any one of claims 1 to 9, comprising: a step of determining a first change amount of the battery temperature, a first charging time, and a first average external temperature when a first charging stage of the battery is in progress; a step of determining a first reference change amount of the battery temperature based on a first starting temperature, the first charging time, and the first average external temperature using the first reference map, wherein the first starting temperature is the battery temperature obtained at the start of the first charging stage; and a step of determining whether the battery is faulty by comparing the first change amount with the first reference change amount.

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