Battery internal resistance estimation device and method

Abstract

The present invention relates to a battery internal resistance estimation device and method, and a battery internal resistance estimation device according to one embodiment of the present invention includes: a storage unit that stores a plurality of battery charging information items obtained by charging a battery with a plurality of constant currents; and a control unit that reads a plurality of battery charging information items having an initial SOC that is the same as a target initial SOC from the plurality of battery charging information items, determines whether there is battery charging information item corresponding to a constant current that matches the target constant current from the read plurality of battery charging information items; and, when the determination results in no battery charging information item corresponding to a constant current that matches the target constant current, estimates the target initial SOC and the internal resistance of the battery due to charging with the target constant current using two battery charging information items corresponding to two constant currents adjacent to the target constant current.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0184424, filed December 18, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for estimating the internal resistance of a battery and a battery internal resistance estimation device for performing the method. [Background technology]

[0003] Batteries installed in high-power products such as electric vehicles or hybrid vehicles must supply high voltage to a load and therefore include a number of cells connected in series or parallel. As the vehicle is driven, battery deterioration and degradation occur, causing an increase in the internal resistance of the battery.

[0004] Calculating the internal resistance of a battery is important because it is used as an important indicator when estimating battery conditions such as the battery's state of charge (SOC) and state of health (SOH). Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a method for estimating the internal resistance of a battery in any battery charging environment using battery charging information when charged by constant current (CC), and a battery internal resistance estimation device for performing the method. [Means for solving the problem]

[0006] A battery internal resistance estimation device according to one embodiment of the present invention includes a storage unit that stores multiple battery charging information obtained by multiple constant current charging of a battery, and a control unit that reads multiple battery charging information having an initial SOC that is the same as a target initial SOC from the multiple battery charging information, determines whether there is battery charging information corresponding to a constant current that matches a target constant current from the read multiple battery charging information, and when the determination results in there being no battery charging information using a constant current that matches the target constant current, estimates the target initial SOC and the internal resistance of the battery due to charging with the target constant current using two battery charging information corresponding to two constant currents adjacent to the target constant current.

[0007] The control unit can estimate the target initial SOC and the internal resistance of the battery due to charging at the target constant current using first battery charging information corresponding to the first constant current that is greater than the target constant current and closest to the target constant current among the plurality of battery charging information read out, and second battery charging information corresponding to the second constant current that is smaller than the target constant current and closest to the target constant current among the plurality of battery charging information read out.

[0008] 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 target initial SOC and the internal resistance of the battery due to charging at the target constant current based on the first internal resistance and the second internal resistance.

[0009] The control unit can interpolate the first internal resistance and the second internal resistance to estimate the target initial SOC and the internal resistance of the battery when charged at the target constant current.

[0010] The control unit searches for first spare battery charging information having a constant current that is greater than and closest to the target constant current among the readout plurality of battery charging information, and if there are a plurality of first spare battery charging information, determines, as the first battery charging information, the battery charging information having a battery charging start temperature that is closest to the target battery charging start temperature among the plurality of first spare battery charging information.

[0011] A method for estimating a battery internal resistance according to one embodiment of the present invention includes the steps of storing a plurality of battery charging information items obtained by charging a battery with a plurality of constant currents; reading a plurality of battery charging information items having an initial SOC identical to a target initial SOC from the plurality of battery charging information items; determining whether there is battery charging information corresponding to a constant current that matches a target constant current from the read plurality of battery charging information items; and, when it is determined that there is no battery charging information item corresponding to a constant current that matches the target constant current, estimating the target initial SOC and the internal resistance of the battery due to charging with the target constant current using two battery charging information items corresponding to two constant currents adjacent to the target constant current.

[0012] The step of estimating the target initial SOC and the internal resistance of the battery due to charging at the target constant current may include the steps of determining first battery charging information corresponding to a first constant current that is greater than the target constant current and closest to the target constant current from among the plurality of read battery charging information, determining second battery charging information corresponding to a second constant current that is smaller than the target constant current and closest to the target constant current from among the plurality of read battery charging information, and estimating the target initial SOC and the internal resistance of the battery due to charging at the target constant current using the first battery charging information and the second battery charging information.

[0013] The step of estimating the target initial SOC and the internal resistance of the battery due to charging with the target constant current using the first battery charging information and the second battery charging information may include 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 step of estimating the target initial SOC and the internal resistance of the battery due to charging with the target constant current based on the first internal resistance and the second internal resistance.

[0014] The step of estimating the internal resistance of the battery due to the target initial SOC and charging with the target constant current based on the first internal resistance and the second internal resistance may include the step of interpolating the first internal resistance and the second internal resistance to estimate the internal resistance of the battery due to the target initial SOC and charging with the target constant current.

[0015] The step of determining the first battery charging information corresponding to the first constant current may include the steps of searching for first spare battery charging information having a constant current that is greater than and closest to the target constant current among the readout plurality of battery charging information, and, if there are a plurality of first spare battery charging information, determining, as the first battery charging information, battery charging information having a battery charging start temperature that is closest to the target battery charging start temperature among the plurality of first spare battery charging information. [Effects of the Invention]

[0016] A method for estimating the internal resistance of a battery in any battery charging environment using battery charging information when the battery is charged by a constant current (CC) and a battery internal resistance estimation device for performing the method are provided. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing an example in which a battery internal resistance estimation device according to an embodiment is applied;

[0018] [Figure 2] FIG. 2 is a block diagram illustrating the internal configuration of the vehicle of FIG.

[0019] [Figure 3] FIG. 3 is a block diagram illustrating in detail the configuration of the battery system of FIG. 2.

[0020] [Figure 4] FIG. 2 is a block diagram illustrating in detail the configuration of the battery internal resistance estimation device of FIG. 1.

[0021] [Figure 5] 1 is a flowchart illustrating a method for estimating a target initial SOC and an internal resistance of a battery by charging at a target constant current, according to one embodiment.

[0022] [Figure 6] 4 is a flowchart illustrating a method for determining first battery charging information and second battery charging information according to one embodiment.

[0023] [Figure 7] 10 is a graph showing the change in battery voltage according to the battery charging time. DETAILED DESCRIPTION OF THE INVENTION

[0024] The embodiments described in this specification and the configurations shown in the drawings are preferred examples of the disclosed invention, and there may be various modifications that can replace the embodiments and drawings of this specification at the time of filing this application.

[0025] In describing the embodiments disclosed herein, if it is determined that a detailed description of such known technology may obscure the gist of the embodiments disclosed herein, the detailed description will be omitted. Furthermore, the attached drawings are merely provided to facilitate understanding of the embodiments disclosed herein, and it should be understood that the attached drawings do not limit the technical ideas disclosed herein, and all modifications, equivalents, or alternatives within the spirit and technical scope of the present invention are included.

[0026] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0027] When a component is said to be "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is said to be "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0028] It should be understood that in this application, the use of terms such as "comprise" or "have" is intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof stated in the specification, but does not preclude the possible presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings.

[0030] FIG. 1 is a block diagram showing an example in which a battery internal resistance estimation device according to an embodiment is applied.

[0031] The battery internal resistance estimation device 300 can estimate the internal resistance of a battery mounted on the vehicle 100 (hereinafter referred to as battery internal resistance).

[0032] The battery internal resistance estimation device 300 can acquire information necessary for estimating the battery internal resistance from the vehicle 100 via the server 200. However, the invention is not limited to this, and the battery internal resistance estimation device 300 can acquire the information directly from the vehicle 100.

[0033] According to an embodiment, the vehicle 100 may be an electric vehicle or a hybrid vehicle equipped with the battery system 110. However, the present invention is not limited thereto, and various types of host systems may include the battery system 110 instead of the vehicle 100.

[0034] The vehicle 100 and the server 200 can be connected to each other via a network. The network refers to a connection structure that allows information exchange between nodes such as the terminal and the server 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 (registered trademark), Bluetooth (registered trademark), infrared communication, ultrasonic communication, visible light communication (VLC), LiFi, etc.

[0035] The server 200 can receive various data, process and store the received data, and transmit the processed data. More specifically, the server 200 can store battery charge information received from the vehicle 100 and transmit the stored information to the battery internal resistance estimation device 300, and can also transmit the internal resistance estimated by the battery internal resistance estimation device 300 to the vehicle 100.

[0036] FIG. 2 is a block diagram illustrating the internal configuration of the vehicle of FIG.

[0037] FIG. 3 is a block diagram illustrating in detail the configuration of the battery system of FIG.

[0038] Referring to FIG. 2, the vehicle 100 may include a battery system 110, a vehicle control unit 120, an On-Board Diagnostics (OBD) device 130, a vehicle communication unit 140, and an electric device 150.

[0039] 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.

[0040] Two terminals BT1, BT2 of the battery system 110 are connected to the positive and negative poles of a battery 111, a relay 112 is connected between the positive pole of the battery 111 and terminal BT1, and a current sensor 113 is connected between the negative pole of the battery 111 and terminal BT2. A temperature sensor 114 can be located at a predetermined position within the battery system 110, for example, in an area adjacent to the battery 111 or physically coupled to the battery 111.

[0041] The battery 111 includes a plurality of battery cells, which may be connected in series or parallel. In Fig. 3, the battery 111 includes a plurality of battery cells Cell1-Celln, which are connected in series in groups of three parallel-connected battery cells. However, the configuration and the connection relationship between the configurations shown in Fig. 3 are merely examples, and the present invention is not limited thereto.

[0042] The relay 112 controls the electrical connection between the battery system 110 and the electric device 150. When the relay 112 is turned on, the battery system 110 and the electric device 150 are electrically connected to each other to charge or discharge, and when the relay 112 is turned off, the battery system 110 and the electric device 150 are electrically isolated from each other. The electric device 150 may be a load or a charger.

[0043] Specifically, the electric device 150 may include a power conversion device such as an inverter and a converter that converts the power supplied from the battery 111 and supplies power to electrical loads of the vehicle 100, such as a motor, an air conditioner, a display, etc. If the electric device 150 is a charger, the battery 111 can be charged by the energy supplied from the electric device 150.

[0044] The current sensor 113 is connected in series to a current path between the battery 111 and the electric device 150. The current sensor 113 measures the current I_pack flowing through the battery 111 and can transmit a detection signal CS indicating the measurement result to the battery management system 115. The current flowing through the battery 111 can be a charging current that charges the battery 111 or a discharging current supplied from the battery 111 to the electric device 150.

[0045] The temperature sensor 114 can detect the temperature at a location where it is located and transmit a signal TS indicating the detected temperature to the battery management system 115. The temperature sensor 114 is not limited to the one shown in FIG. 3, and at least two temperature sensors 114 can be provided to detect the temperatures of cells of multiple batteries.

[0046] The battery management system 115 includes a monitoring unit 115a, an MCU (Main Control Unit) 115b, a memory 115c, and a communication unit 115d.

[0047] The monitoring unit 115a is electrically connected to the positive and negative electrodes of each of the plurality of battery cells Cell1-Celln and measures the voltage of each of the plurality of battery cells Cell1-Celln.

[0048] The monitoring unit 115a transmits information related to the measured cell voltages of each of the plurality of battery cells Cell1-Celln to the MCU 115b. Specifically, the monitoring unit 115a can measure the cell voltages of each of the plurality of battery cells Cell1-Celln at predetermined intervals during a rest period when no charging or discharging occurs and transmit the measured cell voltages to the MCU 115b, and the monitoring unit 115a can measure the voltage across the battery 111 (hereinafter referred to as the battery voltage) at predetermined intervals during constant current charging and transmit information related to the measured battery voltages to the MCU 115b.

[0049] The MCU 115b can estimate the SOC (state of charge) of each of the plurality of battery cells by using the cell voltages of each of the plurality of battery cells Cell1-Celln received from the monitoring unit 115a during the sleep period.

[0050] 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 to the total capacity of the battery 111. For example, the SOC of the battery according to the battery voltage transmitted from the monitoring unit 115a can be estimated by 1) averaging (using the SOC of multiple battery cells) or 2) using a function or table indicating the relationship between the battery voltage and the SOC of the battery. 3) The SOC of the battery 111 can be estimated by integrating the battery current. The method of estimating the SOC of the battery according to the battery voltage can be realized by various known techniques, and the present invention is not limited to a specific method.

[0051] The MCU 115b can obtain the level of the current flowing through the battery 111 during the charging and discharging period of the battery 111 based on the detection signal CS received from the current sensor 113.

[0052] The MCU 115b can use the received detection signal CS to determine the levels of the currents I_c1, I_c2, and I_c3 flowing through each of the battery cells Cell1-Celln. For example, the MCU 115b can divide the battery current level indicated by the detection signal CS by 3 to calculate the currents I_c1, I_c2, and I_c3 flowing through each cell.

[0053] The MCU 115b can obtain the temperature level of the battery 111 from the detection signal TS received from the temperature sensor 114.

[0054] The memory 115c can store programs and data related to the battery management operation performed by the MCU 115b, information acquired by the current sensor 113, the temperature sensor 114, and the monitoring unit 115a, information calculated by the MCU 115b, and the like.

[0055] Specifically, the memory 115c can store battery charging information acquired during constant current charging. For example, the battery charging information can include the magnitude 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 due to charging.

[0056] The communication unit 115d can transmit information read from the memory 115c by the MCU 115b to the vehicle control unit 120 in response to an instruction from the MCU 115b, and can also receive a control instruction input from the vehicle control unit 120.

[0057] The vehicle control unit 120 can control the vehicle 100 including the battery system 110 in its entirety.

[0058] Specifically, the vehicle control unit 120 can transmit a signal to adjust the battery output to the battery system 110, can transmit the battery status, battery charging information, etc. received from the battery system 110 to the OBD device 130, and can control the vehicle communication unit 140 to communicate with the server 200 and an external terminal.

[0059] The OBD device 130 can monitor the status and performance of the vehicle 100 based on information received from the vehicle control unit 120, provide the monitored information to the driver of the vehicle 100, and when a problem occurs during monitoring, generate an error code and provide it to the driver of the vehicle 100.

[0060] Specifically, the OBD device 130 can monitor the 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.

[0061] The OBD device 130 can also store information used for monitoring, such as driving history, battery charging information, and monitoring information for the electrical device 150.

[0062] 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 may receive an estimated internal resistance from the internal resistance estimation device.

[0063] FIG. 4 is a block diagram illustrating in detail the configuration of the battery internal resistance estimation device of FIG.

[0064] FIG. 5 is a flow chart illustrating a method for estimating a target initial SOC and a battery's internal resistance due to target constant current charging, according to one embodiment.

[0065] 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.

[0066] 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 may transmit an estimated internal resistance to the server 200.

[0067] The storage unit 320 may store a program and data for estimating the internal resistance of a battery. Specifically, the storage unit 320 may store a plurality of pieces of battery charging information received from the server 200 and may store an interpolation algorithm for estimating the internal resistance of a battery.

[0068] The control unit 330 can estimate the internal resistance of the battery according to the battery charging conditions set based on the plurality of pieces of battery charging information stored in the storage unit 320. The battery charging conditions include the SOC of the battery at the start of charging (hereinafter referred to as the target initial SOC), the constant current used for charging (hereinafter referred to as the target constant current Ita), and the temperature at the start of battery charging (hereinafter referred to as the target temperature).

[0069] The battery charging conditions may be input by the user via the communication unit 310. However, the setting of the battery charging conditions is not limited to this, and the conditions can be set using a plurality of pieces of battery charging information.

[0070] For example, if there is only battery charging information with a constant current of 50 A and battery charging information with a constant current of 70 A, the battery charging conditions can be set with a target constant current Ita being a constant current of 60 A, which is the average value of the two constant currents.

[0071] Referring to FIG. 5, the control unit 330 may read out charging information for a plurality of batteries having the same initial SOC as the target initial SOC from the storage unit 320 (S1000).

[0072] For example, if the target initial SOC is 20%, the control unit 330 can read out only the battery charging information for the plurality of batteries whose SOC at the start of charging (hereinafter, initial SOC) is 20% from among the plurality of battery charging information.

[0073] Control unit 330 can determine whether or not there is battery charging information corresponding to a constant current that matches target constant current Ita among the plurality of pieces of battery charging information that have been read out (S1100).

[0074] For example, if the target constant current Ita is 65 A, the control unit can determine whether or not there is battery charging information indicating that charging was performed at 65 A among the plurality of battery charging information that has been read out.

[0075] If the control unit 330 finds that there is battery charging information corresponding to a constant current that matches the target constant current Ita among the multiple battery charging information that it has read out (Yes in S1100), the control unit 330 can estimate the internal resistance according to the battery charging information (S1200).

[0076] The control unit 330 can estimate the target initial SOC and the internal resistance of the battery due to charging at the target constant current Ita by dividing the difference between the battery voltage at the start of charging and the battery voltage at the end of charging, which is part of the battery charging information, by the constant current used for charging.

[0077] The control unit 330 can also 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, which is included in the battery charging information, by the current flowing through each cell.

[0078] If there is no battery charging information corresponding to a constant current that matches the target constant current Ita among the multiple battery charging information that has been read out (No in S1100), the control unit 330 can use the battery charging information to determine the first battery charging information and the second battery charging information (S1300).

[0079] The control unit 330 can determine two pieces of battery charging information corresponding to two constant currents adjacent to the target constant current Ita as the first battery charging information and the second battery charging information.

[0080] Specifically, the control unit 330 may determine the battery charging information corresponding to the first constant current I1 that is greater than the target constant current Ita and closest to the target constant current Ita as the first battery charging information, and may determine the battery charging information corresponding to the second constant current I2 that is smaller than the target constant current Ita and closest to the target constant current Ita as the second battery charging information.

[0081] FIG. 6 is a flow chart illustrating a method for determining first battery charging information and second battery charging information according to one embodiment.

[0082] Determining the first battery charging information and the second battery charging information will now be described with reference to FIG.

[0083] The control unit 330 may search for first auxiliary battery charging information having the nearest constant current greater than the target constant current Ita (S1310). The control unit 330 may determine whether there are multiple pieces of first auxiliary battery charging information (S1320).

[0084] If there are multiple pieces of first spare battery charging information (Yes in S1320), the control unit 330 can compare the target temperature with multiple temperatures at the start of battery charging in the multiple pieces of first spare battery charging information to determine the first battery charging information (S1330).

[0085] Specifically, if there is first spare battery charging information among multiple first spare battery charging information that has a temperature at the start of battery charging that is the same as the target temperature, the control unit 330 can determine that first spare battery charging information as the first battery charging information.

[0086] Furthermore, if there is no first auxiliary battery charging information having the same temperature at the start of battery charging as the target temperature among the plurality of first auxiliary battery charging information, the control unit 330 may determine the first auxiliary 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 first auxiliary battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging, the control unit 330 may determine any one of them as the first battery charging information.

[0087] If there are no multiple pieces of first auxiliary battery charging information (No in S1320), control unit 330 may determine the first auxiliary battery charging information as the first battery charging information (S1340).

[0088] The control unit 330 may search for second auxiliary battery charging information having the nearest constant current smaller than the target constant current Ita (S1350). The control unit 330 may determine whether there are multiple pieces of second auxiliary battery charging information (S1360).

[0089] If there are multiple pieces of second spare battery charging information (Yes in S1360), the control unit 330 can compare the target temperature with multiple temperatures at the start of battery charging in the multiple pieces of spare battery charging information to determine the second battery charging information (S1370).

[0090] Specifically, if there is second spare battery charging information among multiple second spare battery charging information that has a temperature at the start of battery charging that is the same as the target temperature, the control unit 330 can determine that second spare battery charging information as the second battery charging information.

[0091] Furthermore, if there is no second auxiliary battery charging information having the same temperature at the start of battery charging as the target temperature among the plurality of second auxiliary battery charging information, the control unit 330 may determine, as the second battery charging information, the second auxiliary 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.If there are multiple pieces of second auxiliary battery charging information having the smallest difference between the target temperature and the temperature at the start of battery charging, the control unit 330 may determine any one of them as the second battery charging information.

[0092] If there are no multiple pieces of second auxiliary battery charging information (No in S1360), control unit 330 may determine the second auxiliary battery charging information as the second battery charging information (S1380).

[0093] Referring to FIG. 5, the control unit 330 can estimate the internal resistance of the battery (hereinafter, the first internal resistance R1) according to the first constant current I1 using the first battery charging information, and can estimate the internal resistance of the battery (hereinafter, the second internal resistance R2) according to the second constant current I2 using the second battery charging information (S1400).

[0094] FIG. 7 is a graph showing the change in battery voltage depending on the battery charging time.

[0095] Referring to FIG. 7, a method for determining the internal resistance of a battery using battery charge information will be described.

[0096] In the graph, the Y axis represents voltage, the X axis represents time, T1 is the start point of charging, T2 is the end point of charging, V1 is the battery voltage at the start of charging, V2 and V3 are 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.

[0097] The control unit 330 can determine the internal resistance by dividing the amount of change in voltage 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 shown in graph A by the first constant current I1. 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 shown in graph B by the second constant current I2.

[0098] The control unit 330 can interpolate the first internal resistance R1 and the second internal resistance R2 to estimate the target initial SOC and the internal resistance of the battery when charged at the target constant current Ita (S1500).

[0099] For example, the control unit 330 can estimate the internal resistance using Equation 1 or Equation 2.

[0100] (Equation 1)

number

[0101] (Equation 2)

number

[0102] When the first internal resistance R1 and the second internal resistance R2 are interpolated using Equation 1 or Equation 2, the internal resistance resulting from charging at a target constant current having voltage characteristics like the graph TA in FIG. 7 can be estimated.

[0103] If the internal resistance of the battery due to charging at the target constant current is equal to or greater than a predetermined reference value, the control unit 330 may notify the user or transmit the information to the vehicle 100 via the server 200 .

[0104] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to these examples, and various modifications and improvements made by those skilled in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

1. a storage unit for storing a plurality of pieces of battery charging information acquired by a plurality of constant current charging operations for the battery; a control unit that reads out a plurality of battery charging information items having an initial SOC identical to a target initial SOC from the plurality of battery charging information items, determines whether there is battery charging information corresponding to a constant current that matches a target constant current from the read out plurality of battery charging information items, and if it determines that there is no battery charging information item using a constant current that matches the target constant current, estimates the target initial SOC and the internal resistance of the battery when charging with the target constant current using battery charging information items corresponding to a constant current adjacent to the target constant current.

2. The control unit 2. The battery internal resistance estimation device according to claim 1, wherein the target initial SOC and the internal resistance of the battery due to charging at the target constant current are estimated using first battery charging information corresponding to a first constant current that is greater than the target constant current and closest to the target constant current among the plurality of battery charging information read out, and second battery charging information corresponding to a second constant current that is smaller than the target constant current and closest to the target constant current among the plurality of battery charging information read out.

3. The control unit 3. The battery internal resistance estimation device according to claim 2, wherein a first internal resistance of the battery is determined using the first battery charging information, a second internal resistance of the battery is determined using the second battery charging information, and the target initial SOC and the internal resistance of the battery resulting from charging at the target constant current are estimated based on the first internal resistance and the second internal resistance.

4. The control unit 4. The battery internal resistance estimation device according to claim 3, wherein the first internal resistance and the second internal resistance are interpolated to estimate the target initial SOC and the internal resistance of the battery when charged at the target constant current.

5. The control unit 3. The battery internal resistance estimation device according to claim 2, wherein the first spare battery charging information having a constant current greater than and closest to the target constant current is searched for among the plurality of read battery charging information, and when there are a plurality of first spare battery charging information, the battery charging information having a battery charging start temperature closest to the target battery charging start temperature among the plurality of first spare battery charging information is determined as the first battery charging information.

6. storing a plurality of battery charging information obtained by a plurality of constant current charging operations for the battery; reading out a plurality of battery charging information items having the same initial SOC as the target initial SOC from among the plurality of battery charging information items; determining whether there is battery charging information corresponding to a constant current that matches the target constant current among the plurality of battery charging information read out; and estimating the target initial SOC and the internal resistance of the battery when charging at the target constant current using battery charging information corresponding to a constant current adjacent to the target constant current when it is determined that there is no battery charging information at a constant current matching the target constant current.

7. The step of estimating the target initial SOC and the internal resistance of the battery due to charging at the target constant current includes: determining first battery charging information corresponding to a first constant current that is greater than the target constant current and closest to the first constant current among the plurality of battery charging information read out; determining second battery charging information corresponding to a second constant current that is smaller than the target constant current and closest to the target constant current among the plurality of battery charging information read out; 7. The method of claim 6, further comprising: estimating the target initial SOC and the internal resistance of the battery resulting from charging at the target constant current using the first battery charging information and the second battery charging information.

8. The step of estimating the target initial SOC and the internal resistance of the battery due to charging at the target constant current using the first battery charging information and the second battery charging information includes: determining a first internal resistance of the battery using the first battery charging information; determining a second internal resistance of the battery using the second battery charging information; 8. The method of claim 7, further comprising: estimating the target initial SOC and the internal resistance of the battery when charged at the target constant current based on the first internal resistance and the second internal resistance.

9. The step of estimating the target initial SOC and the internal resistance of the battery when charged at the target constant current based on the first internal resistance and the second internal resistance includes:

9. The method of claim 8, further comprising: interpolating the first internal resistance and the second internal resistance to estimate the target initial SOC and the internal resistance of the battery when charged at the target constant current.

10. Determining first battery charging information corresponding to a first constant current comprises: searching for first spare battery charging information having a constant current that is greater than the target constant current and closest to the target constant current among the plurality of battery charging information read out; and determining, when the first spare battery charging information is plural, battery charging information having a battery charging start temperature that is closest to a target battery charging start temperature among the plurality of first spare battery charging information as the first battery charging information.

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