Apparatus and method of estimating the battery internal resistance

Abstract

The present invention relates to an apparatus and method for estimating the internal resistance of a battery. The apparatus for estimating the internal resistance of a battery, according to an embodiment of the present invention, comprises: a storage unit that stores a plurality of pieces of battery charging information obtained during a plurality of constant current charging of a battery; and a control unit that reads a plurality of pieces of battery charging information having the same initial SOC as a target initial SOC from among the plurality of pieces of battery charging information, determines whether there is battery charging information corresponding to a constant current matching a target constant current from among the plurality of pieces of read battery charging information, and when a result of the determination is that there is no battery charging information according to the constant current matching the target constant current, estimates the internal resistance of the battery according to the target initial SOC and the target constant current charging by using two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current.

Description

Battery internal resistance estimation device and method

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0184424, filed December 18, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a method for estimating internal resistance of a battery and a device for estimating internal resistance of a battery performing the method.

[0004] Batteries used in high-power products, such as electric or hybrid vehicles, must supply high voltages to the load, so they contain multiple cells connected in series or parallel. As the vehicle operates, battery deterioration and degradation occur, increasing the battery's internal resistance.

[0005] Calculating the battery internal resistance is important because it is used as an important indicator in estimating the battery status, such as the battery's state of charge (SOC) and state of health (SOH).

[0006] The present invention provides a method for estimating the internal resistance of a battery in an arbitrary battery charging environment using battery charging information when charged by a constant current (CC), and a battery internal resistance estimation device performing the method.

[0007] According to one embodiment of the present invention, a battery internal resistance estimation device includes a storage unit that stores a plurality of battery charging information obtained from a plurality of constant current charges for a battery, and a control unit that reads out a plurality of battery charging information having an initial SOC identical to a target initial SOC from among the plurality of battery charging information, determines whether there is battery charging information corresponding to a constant current matching the target constant current from among the plurality of read battery charging information, and estimates the target initial SOC and the internal resistance of the battery according to the target constant current charging by using two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current when there is no battery charging information according to the constant current matching the target constant current as a result of the determination.

[0008] The control unit can estimate the target initial SOC and the internal resistance of the battery according to the target constant current charging by using the first battery charging information corresponding to the first constant current that is larger than the target constant current and closest among the plurality of battery charging information read out, and the second battery charging information corresponding to the second constant current that is smaller than the target constant current and closest among the plurality of battery charging information read out.

[0009] The control unit can determine a first internal resistance of the battery using the first battery charging information, determine a second internal resistance of the battery using the second battery charging information, and estimate the internal resistance of the battery according to the target initial SOC and the target constant current charging based on the first internal resistance and the second internal resistance.

[0010] The control unit can estimate the internal resistance of the battery according to the target initial SOC and the target constant current charge by interpolating the first internal resistance and the second internal resistance.

[0011] The control unit may search for first reserve battery charging information having a constant current that is larger than the target constant current and closest to the target constant current among the plurality of battery charging information, and, when there are multiple pieces of first reserve battery charging information, determine battery charging information having a temperature at the start of battery charging that is closest to the temperature at the start of target battery charging among the plurality of first reserve battery charging information as the first battery charging information.

[0012] According to one embodiment of the present invention, a battery internal resistance estimation method includes the steps of: storing a plurality of battery charging information obtained from a plurality of constant current charges for a battery; reading out a plurality of battery charging information having an initial SOC identical to a target initial SOC from among the plurality of battery charging information; determining whether there is battery charging information corresponding to a constant current matching a target constant current from among the plurality of battery charging information read out; and, when there is no battery charging information according to a constant current matching the target constant current as a result of the determination, estimating the target initial SOC and the internal resistance of the battery according to the target constant current charge using two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current.

[0013] The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charging may include the step of determining first battery charging information corresponding to a first constant current that is larger than the target constant current and closest among the plurality of battery charging information read out, the step of determining second battery charging information corresponding to a second constant current that is smaller than the target constant current and closest among the plurality of battery charging information read out, and the step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charging using the first battery charging information and the second battery charging information.

[0014] The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge using the first battery charging information and the second battery charging information may include the step of determining the first internal resistance of the battery using the first battery charging information, the step of determining the second internal resistance of the battery using the second battery charging information, and the step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge based on the first internal resistance and the second internal resistance.

[0015] The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge based on the first internal resistance and the second internal resistance may include the step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge by interpolating the first internal resistance and the second internal resistance.

[0016] The step of determining the first battery charging information corresponding to the first constant current may include the step of searching for the first reserve battery charging information having a constant current that is larger than the target constant current and closest among the plurality of battery charging information read out, and when the number of the first reserve battery charging information is plural, the step of determining the battery charging information having a temperature at the start of battery charging that is closest to the temperature at the start of target battery charging among the plurality of first reserve battery charging information as the first battery charging information.

[0017] A method for estimating the internal resistance of a battery in an arbitrary battery charging environment using battery charging information when charged by a constant current (CC) and a battery internal resistance estimation device performing the method are provided.

[0018] FIG. 1 is a block diagram showing an example in which a battery internal resistance estimation device according to one embodiment is applied.

[0019] Figure 2 is a block diagram illustrating the internal configuration of the vehicle of Figure 1.

[0020] Figure 3 is a block diagram detailing the configuration of the battery system of Figure 2.

[0021] Fig. 4 is a block diagram detailing the configuration of the battery internal resistance estimation device of Fig. 1.

[0022] FIG. 5 is a flowchart illustrating a method for estimating battery internal resistance according to a target initial SOC and target constant current charge according to one embodiment.

[0023] FIG. 6 is a flowchart illustrating a method for determining first battery charging information and second battery charging information according to one embodiment.

[0024] Figure 7 is a graph showing changes in battery voltage according to battery charging time.

[0025] The embodiments described in this specification and the configurations illustrated in the drawings are preferred examples of the disclosed invention, and there may be various modified examples that can replace the embodiments and drawings of this specification at the time of filing of this application.

[0026] In describing the embodiments disclosed in this specification, detailed descriptions of related known technologies will be omitted if it is determined that such detailed descriptions may obscure the gist of the embodiments disclosed in this specification. In addition, the attached drawings are provided solely to facilitate understanding of the embodiments disclosed in this specification, and the technical concepts disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention.

[0027] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0028] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0029] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0030] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings.

[0031] FIG. 1 is a block diagram showing an example in which a battery internal resistance estimation device according to one embodiment is applied.

[0032] The battery internal resistance estimation device (300) can estimate the internal resistance of a battery (hereinafter, battery internal resistance) installed in a vehicle (100).

[0033] The battery internal resistance estimation device (300) can obtain information necessary for estimating the battery internal resistance from the vehicle (100) through the server (200). However, the invention is not limited thereto, and the battery internal resistance estimation device (300) can obtain the corresponding information directly from the vehicle (100).

[0034] According to one embodiment, the vehicle (100) may be an electric vehicle or a hybrid vehicle equipped with a battery system (110). However, the present invention is not limited thereto, and various types of upper systems may include the battery system (110) instead of the vehicle (100).

[0035] The vehicle (100) and the server (200) can be connected to each other through a network. The network refers to a connection structure that enables information exchange between each node, such as terminals and servers (200), and includes a local area network (LAN), a wide area network (WAN), the Internet (WWW), a wired and wireless data communication network, a telephone network, a wired and wireless television communication network, etc. Examples of wireless data communication networks include 4G, 5G, LTE (Long Term Evolution), Wi-Fi, Bluetooth communication, infrared communication, ultrasonic communication, visible light communication (VLC), LiFi, etc.

[0036] The server (200) can receive various types of data, process and store the received data, and transmit the processed data. More specifically, the server (200) can store battery charging information received from the vehicle (100), transmit the same to the battery internal resistance estimation device (300), and transmit the internal resistance estimated by the battery internal resistance estimation device (300) to the vehicle (100).

[0037] Figure 2 is a block diagram illustrating the internal configuration of the vehicle of Figure 1.

[0038] Figure 3 is a block diagram detailing the configuration of the battery system of Figure 2.

[0039] Referring to FIG. 2, a vehicle (100) may include a battery system (110), a vehicle control unit (120), an OBD (On-Board Diagnostics) device (130), a vehicle communication unit (140), and an electrical device (150).

[0040] Referring to FIG. 3, the battery system (110) includes a battery (111), a relay (112), a current sensor (113), a temperature sensor (114), and a battery management system (BMS) (115).

[0041] Two terminals (BT1, BT2) of the battery system (110) are connected to the positive and negative poles of the battery (111), a relay (112) is connected between the positive pole of the battery (111) and the terminal (BT1), and a current sensor (113) is connected between the negative pole of the battery (111) and the terminal (BT2). A temperature sensor (114) may be located at a predetermined location within the battery system (110), for example, in an area adjacent to the battery (111), or may be located by being physically coupled to the battery (111).

[0042] The battery (111) includes a plurality of battery cells, and the plurality of battery cells may be connected in series / parallel. In FIG. 3, the battery (111) includes a plurality of battery cells (Cell1-Celln), and the plurality of battery cells (Cell1-Celln) are three battery cells connected in parallel and connected in series. However, the configurations and connection relationships between the configurations illustrated in FIG. 3 are merely examples, and the invention is not limited thereto.

[0043] The relay (112) controls the electrical connection between the battery system (110) and the electrical device (150). When the relay (112) is turned on, the battery system (110) and the electrical device (150) are electrically connected to perform charging or discharging, and when the relay (112) is turned off, the battery system (110) and the electrical device (150) are electrically separated. The electrical device (150) may be a load or a charger.

[0044] Specifically, the electric device (150) may include a power conversion device such as an inverter and a converter that converts power supplied from a battery (111) and supplies power to electric loads of the vehicle (100), such as a motor, an air conditioner, a display, etc. When the electric device (150) is a charger, the battery (111) may be charged by energy supplied from the electric device (150).

[0045] The current sensor (113) is connected in series to the current path between the battery (111) and the electrical device (150). The current sensor (113) can measure the current (I_pack) flowing in the battery (111) and transmit a detection signal (CS) indicating the measurement result to the battery management system (115). The current flowing in the battery (111) may be a charging current for charging the battery (111) or a discharging current supplied from the battery (111) to the electrical device (150).

[0046] A temperature sensor (114) can detect the temperature of a location and transmit a signal (TS) indicating the detected temperature to a battery management system (115). The temperature sensor (114) is not limited to that shown in FIG. 3, and at least two temperature sensors may be provided to detect the temperature of cells of multiple batteries.

[0047] The battery management system (115) includes a monitoring unit (115a), an MCU (Main Control Unit) (115b), a memory (115c), and a communication unit (115d).

[0048] The monitoring unit (115a) is electrically connected to the positive and negative poles of each of the plurality of battery cells (Cell1-Celln) and measures the voltage of each of the plurality of battery cells (Cell1-Celln).

[0049] The monitoring unit (115a) transmits information about the cell voltage of each of the plurality of measured battery cells (Cell1-Celln) to the MCU (115b). Specifically, the monitoring unit (115a) can measure the cell voltage of each of the plurality of battery cells (Cell1-Celln) at predetermined intervals during a rest period in which no charging or discharging occurs, and transmit the measured cell voltage to the MCU (115b). The monitoring unit (115a) can measure the voltage at both ends of the battery (111) (hereinafter, battery voltage) at predetermined intervals during constant current charging, and transmit information about the measured battery voltage to the MCU (115b).

[0050] The MCU (115b) can estimate the SOC (state of charge) of each of the plurality of battery cells using the cell voltage of each of the plurality of battery cells (Cell1-Celln) received from the monitoring unit (115a) during the rest period.

[0051] The MCU (115b) can estimate the SOC of the battery (111). The SOC of the battery (111) can be defined as a ratio representing the charge capacity compared to the total capacity of the battery (111). For example, the battery SOC can be estimated according to the battery voltage transmitted from the monitoring unit (115b) by using 1) an average (using the SOC of multiple battery cells), 2) a function or table indicating the relationship between the battery voltage and the battery SOC. 3) The SOC of the battery (111) can be estimated by integrating the battery current. The method of estimating the battery SOC according to the battery voltage can be implemented using various known technologies, and the present invention is not limited to a specific method.

[0052] The MCU (115b) can obtain the current level flowing in the battery (111) during the battery (111) charging / discharging period according to the detection signal (CS) received from the current sensor (113).

[0053] The MCU (115b) can determine the level of current (I_c1, I_c2, I_c3) flowing in each of the plurality of battery cells (Cell1-Celln) using the received detection signal (CS). For example, the MCU (115b) can divide the battery current level indicated by the detection signal (CS) by 3 to calculate the current (I_c1, I_c2, I_c3) flowing in each cell.

[0054] The MCU (115b) can obtain the temperature level of the battery (111) according to the detection signal (TS) received from the temperature sensor (114).

[0055] The memory (115c) can store programs and data related to battery management operations performed by the MCU (115b). The memory (115c) can store information acquired by the current sensor (113), temperature sensor (114), monitoring unit (115a), and information calculated by the MCU (115b).

[0056] Specifically, the memory (115c) can store battery charging information obtained through constant current charging. For example, the battery charging information can include the size of the constant current used during charging, the SOC at the start of charging, the battery temperature at the start of charging, and changes in battery voltage according to charging.

[0057] The communication unit (115d) can transmit information read from the memory (115c) by the MCU (115b) to the vehicle control unit (120) according to the command of the MCU (115b) and can also receive a control command input from the vehicle control unit (120).

[0058] The vehicle control unit (120) can control the vehicle (100) including the battery system (110) as a whole.

[0059] Specifically, the vehicle control unit (120) can transmit a signal for controlling battery output to the battery system (110), transmit battery status, battery charging information, etc. received from the battery system (110), to the OBD device (130), and control the vehicle communication unit (140) to communicate with a server (200) or an external terminal.

[0060] The OBD device (130) can monitor the status and performance of the vehicle (100) based on information received from the vehicle control unit (120) and provide the monitored information to the driver of the vehicle (100). When a problem occurs during monitoring, the device can generate an error code and provide it to the driver of the vehicle (100).

[0061] Specifically, the OBD device (130) can monitor battery charging information received from the vehicle control unit (120) and provide the monitored battery charging information to the driver of the vehicle (100), and if a problem occurs during battery charging, can generate an error code and provide it to the driver of the vehicle (100).

[0062] Additionally, the OBD device (130) may store information used for monitoring. For example, the OBD device (130) may store driving history, battery charging information, electrical device (150) monitoring information, etc.

[0063] The vehicle communication unit (140) may include a communication module capable of communicating with the server (200). The vehicle communication unit (140) may transmit information to the server (200) and receive information from the server (200). For example, the vehicle communication unit (140) may transmit information stored in the OBD device (130) to the server (200) and receive an estimated internal resistance from an internal resistance estimation device.

[0064] Fig. 4 is a block diagram detailing the configuration of the battery internal resistance estimation device of Fig. 1.

[0065] FIG. 5 is a flowchart illustrating a method for estimating battery internal resistance according to a target initial SOC and target constant current charge according to one embodiment.

[0066] Referring to FIG. 4, the battery internal resistance estimation device (300) may include a communication unit (310), a storage unit (320), and a control unit (330).

[0067] The communication unit (310) may include a communication module capable of communicating with the server (200). Specifically, the communication unit (310) may receive vehicle information, such as battery charging information, from the server (200) and transmit the estimated internal resistance to the server (200).

[0068] The storage unit (320) can store programs and data for estimating the internal resistance of a battery. Specifically, the storage unit (320) can store a plurality of pieces of battery charging information received from the server (200) and can store an interpolation algorithm for estimating the internal resistance of a battery.

[0069] The control unit (330) can estimate the internal resistance of the battery according to the set battery charging conditions based on the plurality of battery charging information stored in the storage unit (320). The battery charging conditions can include the battery SOC at the start of charging (hereinafter, target initial SOC), the constant current used for charging (hereinafter, target constant current (Ita)), and the temperature at the start of battery charging (hereinafter, target temperature).

[0070] Battery charging conditions can be input by the user through the communication unit (310). However, the battery charging conditions are not limited to this and can be set using multiple battery charging information.

[0071] For example, if there is only battery charging information by a 50A constant current and battery charging information by a 70A constant current, the battery charging condition can be set by using the 60A constant current, which is the average value of the two constant currents, as the target constant current (Ita).

[0072] Referring to FIG. 5, the control unit (330) can read out charging information of multiple batteries having the same initial SOC as the target initial SOC from the storage unit (320) (S1000).

[0073] For example, if the target initial SOC is 20%, the control unit (330) can read only the plurality of battery charging information whose SOC at the start of charging (hereinafter, initial SOC) is 20% among the plurality of battery charging information.

[0074] The control unit (330) can determine whether there is battery charging information corresponding to a constant current that matches the target constant current (Ita) among the plurality of battery charging information read out (S1100).

[0075] For example, if the target constant current (Ita) is 65 A, the control unit can determine whether battery charging information that is charged by 65 A exists among the plurality of battery charging information read out.

[0076] If there is battery charging information corresponding to a constant current matching the target constant current (Ita) among the plurality of battery charging information read out (example of S1100), the control unit (330) can estimate the internal resistance based on the battery charging information (S1200).

[0077] The control unit (330) can estimate the internal resistance of the battery according to the target initial SOC and target constant current (Ita) charging by dividing the difference between the battery voltage at the start of charging and the battery voltage at the end of charging among the battery charging information by the constant current used for charging.

[0078] Additionally, the control unit (330) can estimate the internal resistance of the cells by dividing the difference between the cell voltage at the start of charging and the cell voltage at the end of charging among the battery charging information by the current flowing in each cell.

[0079] If there is no battery charging information corresponding to a constant current matching the target constant current (Ita) among the plurality of battery charging information read out (NO in S1100), the control unit (330) can determine the first battery charging information and the second battery charging information using the battery charging information (S1300).

[0080] The control unit (330) can determine two battery charging information corresponding to two constant currents adjacent to the target constant current (Ita) as first battery charging information and second battery charging information.

[0081] Specifically, the control unit (330) can determine battery charging information corresponding to the first constant current (I1) that is larger than the target constant current (Ita) and closest among the read-out battery charging information as the first battery charging information, and can determine battery charging information corresponding to the second constant current (I2) that is smaller than the target constant current (Ita) and closest among the read-out battery charging information as the second battery charging information.

[0082] FIG. 6 is a flowchart illustrating a method for determining first battery charging information and second battery charging information according to one embodiment.

[0083] Referring to FIG. 6, determining the first battery charging information and the second battery charging information will be described.

[0084] The control unit (330) can search for the first reserve battery charging information having a larger target constant current (Ita) and the closest constant current (S1310). The control unit (330) can determine whether there are multiple pieces of first reserve battery charging information (S1320).

[0085] When there are multiple pieces of first reserve battery charging information (example of S1320), the control unit (330) can compare the target temperature and multiple temperatures at the start of battery charging of the multiple pieces of first reserve battery charging information to determine the first battery charging information (S1330).

[0086] Specifically, if there is first spare battery charging information having a temperature at the start of battery charging that is the same as the target temperature among the plurality of first spare battery charging information, the control unit (330) may determine the first spare battery charging information as the first battery charging information.

[0087] In addition, if there is no first reserve battery charging information having a temperature at the start of battery charging that is the same as the target temperature among the plurality of first reserve battery charging information, the control unit (330) may determine the first reserve battery charging information having the battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging as the first battery charging information. If there are multiple pieces of battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging among the plurality of first reserve battery charging information, the control unit (330) may arbitrarily determine one of them as the first battery charging information.

[0088] If there are no multiple pieces of first reserve battery charging information (NO in S1320), the control unit (330) can determine the first reserve battery charging information as the first battery charging information (S1340).

[0089] The control unit (330) can search for second reserve battery charging information having a smaller target constant current (Ita) and the closest constant current (S1350). The control unit (330) can determine whether there are multiple pieces of second reserve battery charging information (S1360).

[0090] When there are multiple pieces of second reserve battery charging information (example of S1360), the control unit (330) can compare the target temperature and the multiple temperatures at the start of battery charging of the multiple pieces of reserve battery charging information to determine the second battery charging information (S1370).

[0091] Specifically, if there is second spare battery charging information having a temperature at the start of battery charging that is the same as the target temperature among the plurality of second spare battery charging information, the control unit (330) may determine the second spare battery charging information as the second battery charging information.

[0092] In addition, if there is no second reserve battery charging information having a temperature at the start of battery charging that is the same as the target temperature among the plurality of second reserve battery charging information, the control unit (330) may determine the second reserve battery charging information having the battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging as the second battery charging information. If there are multiple pieces of battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging among the plurality of second reserve battery charging information, the control unit (330) may arbitrarily determine one of them as the second battery charging information.

[0093] If there are no multiple pieces of second reserve battery charging information (NO in S1360), the control unit (330) can determine the second reserve battery charging information as the second battery charging information (S1380).

[0094] Referring to FIG. 5, the control unit (330) can estimate the battery internal resistance (hereinafter, first internal resistance (R1)) according to the first constant current (I1) using the first battery charging information, and can estimate the battery internal resistance (hereinafter, second internal resistance (R2)) according to the second constant current (I2) using the second battery charging information (S1400).

[0095] Figure 7 is a graph showing changes in battery voltage according to battery charging time.

[0096] A method for determining the internal resistance of a battery using battery charge information is described with reference to FIG. 7.

[0097] In the graph, the Y-axis represents voltage, the X-axis represents time, T1 represents the start time of charging, T2 represents the end time of charging, V1 represents the battery voltage at the start of charging, V2 and V3 represent the battery voltages at the end of charging, Graph A is a graph according to the first battery charging information, and Graph B is a graph according to the second battery charging information.

[0098] The control unit (330) can determine the internal resistance by dividing the voltage change amount during the charging period T1-T2 by the constant current. Specifically, the control unit (330) can determine the first internal resistance (R1) by dividing the difference between the voltage V3 at time T2 and the voltage V1 at time T1 in the first battery charging information represented by graph A by the first constant current (I1), and the control unit (330) can determine the second internal resistance (R2) by dividing the difference between the voltage V2 at time T2 and the voltage V1 at time T1 in the second battery charging information represented by graph B by the second constant current (I2).

[0099] The control unit (330) can estimate the internal resistance of the battery according to the target initial SOC and target constant current (Ita) charging by interpolating the first internal resistance (R1) and the second internal resistance (R2) (S1500).

[0100] For example, the control unit (330) can estimate the internal resistance using mathematical expression 1 or mathematical expression 2.

[0101] [Mathematical Formula 1]

[0102]

[0103] [Equation 2]

[0104]

[0105] When the first internal resistance (R1) and the second internal resistance (R2) are interpolated according to mathematical expression 1 or mathematical expression 2, the internal resistance according to the target constant current charging having the voltage characteristic as graph TA in Fig. 7 can be estimated.

[0106] If the internal resistance of the battery according to the target constant current charging is higher than a predetermined standard, the control unit (330) may notify the user of this or transmit this to the vehicle (100) via the server (200).

[0107] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by a person having ordinary skill in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

1. A storage unit storing multiple battery charging information obtained from multiple constant current charges to the battery; and A battery internal resistance estimation device including a control unit that reads out a plurality of battery charging information having an initial SOC identical to a target initial SOC from among the plurality of battery charging information, determines whether there is battery charging information corresponding to a constant current matching the target constant current from among the plurality of battery charging information read out, and, when there is no battery charging information according to a constant current matching the target constant current as a result of the determination, estimates the internal resistance of the battery according to the target initial SOC and the target constant current charging by using two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current.

2. In paragraph 1, The above control unit, A battery internal resistance estimation device that estimates the internal resistance of the battery according to the target initial SOC and the target constant current charging by using the first battery charging information corresponding to the first constant current that is larger than the target constant current and closest among the plurality of battery charging information read out, and the second battery charging information corresponding to the second constant current that is smaller than the target constant current and closest among the plurality of battery charging information read out.

3. In paragraph 2, The above control unit, A battery internal resistance estimation device that determines a first internal resistance of the battery using the first battery charging information, determines a second internal resistance of the battery using the second battery charging information, and estimates the internal resistance of the battery according to the target initial SOC and the target constant current charging based on the first internal resistance and the second internal resistance.

4. In paragraph 3, The above control unit, A battery internal resistance estimation device for estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge by interpolating the first internal resistance and the second internal resistance.

5. In paragraph 2, The above control unit, A battery internal resistance estimation device that searches for first reserve battery charging information having a constant current that is greater than the target constant current and is closest to the target constant current among the plurality of battery charging information read out above, and, when the number of first reserve battery charging information is plural, determines the battery charging information having a temperature at the start of battery charging that is closest to the temperature at the start of target battery charging among the plurality of first reserve battery charging information as the first battery charging information.

6. A step of storing multiple battery charging information obtained from multiple constant current charges to the battery; A step of reading out a plurality of battery charging information having an initial SOC identical to a target initial SOC among the plurality of battery charging information; A step of determining whether there is battery charging information corresponding to a constant current matching the target constant current among the plurality of battery charging information read out above; A method for estimating internal resistance of a battery, comprising the step of estimating the target initial SOC and the internal resistance of the battery according to the target constant current charging by using two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current when there is no battery charging information according to a constant current matching the target constant current as a result of the judgment.

7. In paragraph 6, The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge is: A step of determining first battery charging information corresponding to the first constant current that is greater than the target constant current and is closest to the first constant current among the plurality of battery charging information read out above; A step of determining second battery charging information corresponding to the second constant current that is smaller than the target constant current and closest to the plurality of battery charging information read out above; and A battery internal resistance estimation method comprising the step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge using the first battery charge information and the second battery charge information.

8. In paragraph 7, The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge using the first battery charging information and the second battery charging information is as follows. A step of determining a first internal resistance of the battery using the first battery charging information; A step of determining a second internal resistance of the battery using the second battery charging information; and A method for estimating internal resistance of a battery, comprising the step of estimating internal resistance of the battery according to the target initial SOC and the target constant current charge based on the first internal resistance and the second internal resistance.

9. In paragraph 8, The step of estimating the internal resistance of the battery according to the target initial SOC and the target constant current charge based on the first internal resistance and the second internal resistance is: A method for estimating internal resistance of a battery, comprising the step of interpolating the first internal resistance and the second internal resistance to estimate the internal resistance of the battery according to the target initial SOC and the target constant current charge.

10. In paragraph 7, The step of determining the first battery charge information corresponding to the first constant current is: A step of searching for the first spare battery charging information having a constant current that is greater than the target constant current and is closest to the target constant current among the plurality of battery charging information read out above; and A battery internal resistance estimation method, comprising the step of determining, when the first standby battery charging information is plural, the battery charging information having a temperature at the start of battery charging that is closest to the temperature at the start of target battery charging among the plural first standby battery charging information as the first battery charging information.

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