Battery internal resistance estimation apparatus 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 on December 18, 2023, and all the contents disclosed in the literature of the Korean patent application are included as part of this specification.

[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 Art

[0003] Batteries mounted in high - power products such as electric vehicles or hybrid vehicles include a large number of cells connected in series or parallel because they must supply high voltage to the load. As the vehicle operates, battery degradation and battery deterioration occur, increasing the internal resistance of the battery.

[0004] Since the internal resistance of a battery is used as an important index when estimating battery states such as the state of charge (SOC) and the state of health (SOH) of the battery, it is important to calculate the internal resistance of the battery.

Summary of the Invention

Problems to be Solved by the Invention

[0005] 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 the battery is charged by a constant current (CC), and a battery internal resistance estimation device for performing the method. <00(00024>

Means for Solving the Problems

[0006] A battery internal resistance estimation device according to one embodiment of the present invention includes a storage unit that stores a plurality of battery charge information obtained by a plurality of constant current charges to a battery, and a control unit that reads out a plurality of battery charge information having the same initial SOC as the target initial SOC from the plurality of battery charge information, determines whether there is any battery charge information corresponding to a constant current that matches the target constant current among the read-out plurality of battery charge information, and if as a result of the determination there is no battery charge information by a constant current that matches the target constant current, estimates the target initial SOC and the internal resistance of the battery by charging with the target constant current using two battery charge 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 by using the first battery charge information corresponding to the first constant current that is greater than the target constant current and is closest to the target constant current among the plurality of battery charge information read out, and the second battery charge information corresponding to the second constant current that is smaller than the target constant current and is closest to the target constant current among the plurality of battery charge information read out.

[0008] The control unit can determine the first internal resistance of the battery using the first battery charge information, determine the second internal resistance of the battery using the second battery charge information, and estimate the internal resistance of the battery based on the target initial SOC and the target constant current charge, based on the first and second internal resistances.

[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 due to charging with the target constant current.

[0010] The control unit searches for the first backup battery charge information among the read-out plurality of battery charge information that has a constant current greater than the target constant current and is the closest to it. If there are multiple first backup battery charge information, the control unit can determine the battery charge information among the plurality of first backup battery charge information that has a battery charge start temperature closest to the target battery charge start temperature as the first battery charge information.

[0011] A battery internal resistance estimation method according to one embodiment of the present invention includes the steps of: storing a plurality of battery charge information obtained by a plurality of constant current charges to a battery; reading out a plurality of battery charge information from the plurality of battery charge information having the same initial SOC as the target initial SOC; determining whether there is any battery charge information from the read-out plurality of battery charge information that corresponds to a constant current that matches the target constant current; and, if, as a result of the determination, there is no battery charge information by a constant current that matches the target constant current, estimating the target initial SOC and the internal resistance of the battery by charging with the target constant current using two battery charge information corresponding to two constant currents adjacent to the target constant current.

[0012] The step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current may include: determining a first battery charge information corresponding to the nearest adjacent first constant current that is greater than the target constant current among the read-out plurality of battery charge information; determining a second battery charge information corresponding to the nearest adjacent second constant current that is smaller than the target constant current among the read-out plurality of battery charge information; and using the first battery charge information and the second battery charge information, estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current.

[0013] The step of estimating the internal resistance of the battery by charging with the target initial SOC and target constant current using the first battery charge information and the second battery charge information may include the steps of determining a first internal resistance of the battery using the first battery charge information, determining a second internal resistance of the battery using the second battery charge information, and estimating the internal resistance of the battery by charging with the target initial SOC and target constant current based on the first and second internal resistances.

[0014] The step of estimating the internal resistance of the battery by charging with the target initial SOC and 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 by charging with the target initial SOC and target constant current.

[0015] The step of determining the first battery charge information corresponding to the first constant current may include the step of searching for the first auxiliary battery charge information among the read-out plurality of battery charge information that has a constant current greater than the target constant current and is closest to it, and, if there are plurality of first auxiliary battery charge information, the step of determining the battery charge information among the plurality of first auxiliary battery charge information that has a battery charge start temperature closest to the target battery charge start temperature as the first battery charge information. [Effects of the Invention]

[0016] This invention provides 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 that performs this method. [Brief explanation of the drawing]

[0017] [Figure 1] This block diagram shows an example of a battery internal resistance estimation device according to one embodiment being applied.

[0018] [Figure 2] It is a block diagram for explaining the internal configuration of the vehicle in FIG. 1.

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

[0020] [Figure 4] It is a block diagram for explaining in detail the configuration of the internal resistance estimation device of the battery in FIG. 1. [[ID=I8]]

[0021] [Figure 5] It is a flowchart for explaining a method for estimating the internal resistance of a battery by charging with a target initial SOC and a target constant current according to an embodiment.

[0022] [Figure 6] It is a flowchart for explaining a method for determining first battery charging information and second battery charging information according to an embodiment.

[0023] [Figure 7] It is a graph showing the change in battery voltage according to the battery charging time.

Embodiments for Carrying Out the Invention

[0024] The embodiments described in this specification and the configurations shown in the drawings are a preferred example of the disclosed invention, and there can 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 specific description of such known technology may obscure the essence of the embodiments disclosed herein, such detailed description will be omitted. Furthermore, the accompanying drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed herein, and it should be understood that the accompanying drawings do not limit the technical ideas disclosed herein and include all modifications, equivalents, or substitutions that fall within the concept and technical scope of the present invention.

[0026] Terms including ordinal numbers, such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0027] When it is mentioned that one component is “linked” or “connected” to another component, it should be understood that this may mean that the other component is directly linked to or connected to the other component, but that other components may be in between. Conversely, when it is mentioned that one component is “directly linked” or “directly connected” to another component, it should be understood that there are no other components in between.

[0028] In this application, terms such as “includes” or “having” are intended to specify the presence of features, figures, stages, actions, components, parts, or combinations thereof as described in the specification, and should be understood not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, actions, components, parts, or combinations thereof.

[0029] The embodiments disclosed herein will be described in detail below with reference to the attached drawings.

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

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

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

[0033] The vehicle 100 in one embodiment may be an electric vehicle or a hybrid vehicle equipped with a battery system 110. However, it is not limited to this, and various types of higher-level systems can include the battery system 110 instead of the vehicle 100.

[0034] Vehicle 100 and server 200 can be connected to each other via a network. A network refers to a connected structure that enables information exchange between each node, such as terminals and server 200, and includes local area networks (LANs), wide area networks (WANs), the internet (WWW), wired and wireless data communication networks, telephone networks, and wired and wireless television communication networks. Examples of wireless data communication networks include 4G, 5G, LTE (Long Term Evolution), Wi-Fi (registered trademark), Bluetooth (registered trademark) communication, infrared communication, ultrasonic communication, visible light communication (VLC), and LiFi.

[0035] 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 charge information received from the vehicle 100, transmit this 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.

[0036] Figure 2 is a block diagram illustrating the internal configuration of the vehicle shown in Figure 1.

[0037] Figure 3 is a block diagram that provides a detailed explanation of the battery system configuration shown in Figure 2.

[0038] Referring to Figure 2, the 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.

[0039] Referring to Figure 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 and BT2 of the battery system 110 are connected to the positive and negative terminals of the battery 111, a relay 112 is connected between the positive terminal of the battery 111 and terminal BT1, and a current sensor 113 is connected between the negative terminal of the battery 111 and terminal BT2. The temperature sensor 114 can be located in a predetermined position within the battery system 110, for example, in an area adjacent to the battery 111, or it can be physically coupled to the battery 111.

[0041] The battery 111 includes multiple battery cells, which may be connected in series or parallel. In Figure 3, the battery 111 includes multiple battery cells Cell1-Celln, and the multiple battery cells Cell1-Celln are connected in series in units of three battery cells connected in parallel. However, the configuration and connection relationships between the configurations shown in Figure 3 are just examples, and the invention is not limited thereto.

[0042] Relay 112 controls the electrical connection between the battery system 110 and the electrical device 150. When relay 112 is turned on, the battery system 110 and the electrical device 150 are electrically connected for charging or discharging, and when relay 112 is turned off, the battery system 110 and the electrical device 150 are electrically disconnected. The electrical device 150 may be a load or a charger.

[0043] Specifically, the electrical device 150 may include power conversion devices such as inverters and converters that convert the power supplied from the battery 111 to supply power to the electrical loads of the vehicle 100, such as motors, air conditioners, and displays. If the electrical device 150 is a charger, the battery 111 can be charged by the energy supplied from the electrical device 150.

[0044] 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 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 may be a charging current that charges the battery 111, or a discharge current supplied from the battery 111 to the electrical device 150.

[0045] The temperature sensor 114 can detect the temperature at its location 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 Figure 3, and at least two sensors may be provided to detect the temperatures of multiple battery cells.

[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 multiple battery cells Cell1-Celln and measures the voltage of each of the multiple battery cells Cell1-Celln.

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

[0049] The MCU115b can estimate the state of charge (SOC) of each of the multiple battery cells (Cell1-Celln) using the cell voltages of each of the multiple battery cells (Cell1-Celln) received from the monitoring unit 115a during the idle period.

[0050] The MCU115b can estimate the State of Charge (SOC) of battery 111. The SOC of battery 111 can be defined as the ratio of the charge capacity to the total capacity of battery 111. For example, the SOC of the battery can be estimated according to the battery voltage transmitted from the monitoring unit 115a by 1) averaging (using the SOCs of multiple battery cells), 2) using a function or table that indicates the relationship between battery voltage and the battery SOC, or 3) integrating the battery current to estimate the SOC of battery 111. Methods for estimating the SOC of a battery according to battery voltage can be implemented using a variety of known techniques, and the present invention is not limited to any particular method.

[0051] The MCU115b can acquire the current level flowing through the battery 111 during its charging and discharging period based on the detection signal CS received from the current sensor 113.

[0052] The MCU115b 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 multiple battery cells Cell1-Celln. For example, the MCU115b can calculate the currents I_c1, I_c2, and I_c3 flowing through each cell by dividing the battery current level indicated by the detection signal CS by 3.

[0053] The MCU115b can acquire the temperature level of the battery 111 based on the detection signal TS received from the temperature sensor 114.

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

[0055] Specifically, memory 115c can store battery charging information obtained by constant current charging. For example, the battery charging information may include the magnitude of the constant current used during charging, the state of charge (SOC) at the start of charging, the battery temperature at the start of charging, and the change in battery voltage due to charging.

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

[0057] The vehicle control unit 120 can control the vehicle 100, including the battery system 110, in an overall manner.

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

[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 generate and provide an error code to the driver of the vehicle 100 if a problem occurs during monitoring.

[0060] Specifically, the OBD device 130 can monitor battery charging information received from the vehicle control unit 120, provide the monitored battery charging information to the driver of the vehicle 100, and generate and provide an error code to the driver of the vehicle 100 if a problem occurs during battery charging.

[0061] Furthermore, the OBD device 130 can also store information used for monitoring. For example, the OBD device 130 can store 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 can transmit information to the server 200 and receive information from the server 200. For example, the vehicle communication unit 140 can transmit information stored in the OBD device 130 to the server 200 and receive the internal resistance estimated from the internal resistance estimation device.

[0063] Figure 4 is a block diagram illustrating in detail the configuration of the battery internal resistance estimation device shown in Figure 1.

[0064] Figure 5 is a flowchart illustrating a method for estimating the internal resistance of a battery by charging with a target initial SOC and target constant current, based on one embodiment.

[0065] Referring to Figure 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 can receive vehicle information such as battery charge information from the server 200 and transmit estimated internal resistance to the server 200.

[0067] The storage unit 320 can store programs and data for estimating the internal resistance of the battery. Specifically, the storage unit 320 can store multiple battery charge information received from the server 200 and can store an interpolation algorithm for estimating the internal resistance of the battery.

[0068] The control unit 330 can estimate the internal resistance of the battery according to the battery charging conditions set based on the multiple battery charging information stored in the storage unit 320. The battery charging conditions may include the battery's state of charge (SOC) 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] Battery charging conditions may be input by the user via the communication unit 310. However, the setting of battery charging conditions is not limited to this, and can be set using multiple battery charging information.

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

[0071] Referring to Figure 5, the control unit 330 can read multiple battery charge information from the storage unit 320, each having the same initial SOC as the target initial SOC (S1000).

[0072] For example, if the target initial SOC is 20%, the control unit 330 can read only the battery charge information from among the multiple battery charge information where the SOC at the start of charging (hereinafter referred to as initial SOC) is 20%.

[0073] The control unit 330 can determine whether or not there is battery charge information among the multiple battery charge information read out that corresponds to a constant current that matches the target constant current Ita (S1100).

[0074] For example, if the target constant current Ita is 65A, the control unit can determine whether or not there is any battery charging information among the multiple battery charging information read out that was charged at 65A.

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

[0076] The control unit 330 can estimate the internal resistance of the battery by charging with a target initial SOC and 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, among the battery charging information, by the constant current used for charging.

[0077] Furthermore, the control unit 330 can also estimate the internal resistance of a cell by dividing the difference between the cell voltage at the start of charging and the cell voltage at the end of charging, which is part of the battery charging information, by the current flowing through each cell.

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

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

[0080] Specifically, the control unit 330 can determine the battery charge information corresponding to the nearest adjacent first constant current I1 that is greater than the target constant current Ita from the read battery charge information as the first battery charge information, and can determine the battery charge information corresponding to the nearest adjacent second constant current I2 that is less than the target constant current Ita from the read battery charge information as the second battery charge information.

[0081] Figure 6 is a flowchart illustrating a method for determining the first battery charge information and the second battery charge information according to one embodiment.

[0082] Referring to Figure 6, we will explain how to determine the first battery charge information and the second battery charge information.

[0083] The control unit 330 can search for the first backup battery charge information that has the nearest constant current greater than the target constant current Ita (S1310). The control unit 330 can determine if there are multiple first backup battery charge information entries (S1320).

[0084] If multiple first backup battery charge information entries exist (yes in S1320), the control unit 330 can determine the first battery charge information by comparing the target temperature with multiple temperatures at the start of battery charging for the multiple first backup battery charge information entries (S1330).

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

[0086] Furthermore, if there is no first backup battery charge information among the multiple first backup battery charge information that has the same battery charging start temperature as the target temperature, the control unit 330 can determine the first backup battery charge information having the smallest difference between the target temperature and the battery charging start temperature as the first battery charge information. If there are multiple battery charge information among the multiple first backup battery charge information that have the smallest difference between the target temperature and the battery charging start temperature, the control unit 330 can determine any one of them as the first battery charge information.

[0087] If there are no multiple first backup battery charge information entries (no in S1320), the control unit 330 can determine the first backup battery charge information as the first battery charge information (S1340).

[0088] The control unit 330 can search for the second backup battery charge information that has the nearest constant current smaller than the target constant current Ita (S1350). The control unit 330 can determine if there are multiple second backup battery charge information entries (S1360).

[0089] If there are multiple second backup battery charge information items (yes in S1360), the control unit 330 can determine the second battery charge information by comparing the target temperature with multiple temperatures at the start of battery charging for the multiple backup battery charge information items (S1370).

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

[0091] Furthermore, if there is no second battery charge information among the multiple second backup battery charge information that has the same battery charge start temperature as the target temperature, the control unit 330 can determine the second backup battery charge information having the smallest difference between the target temperature and the battery charge start temperature as the second battery charge information. If there are multiple second backup battery charge information items that have the smallest difference between the target temperature and the battery charge start temperature, the control unit 330 can determine any one of them as the second battery charge information.

[0092] If there are no multiple second backup battery charge information items (no in S1360), the control unit 330 can determine the second backup battery charge information as the second battery charge information (S1380).

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

[0094] Figure 7 is a graph showing the change in battery voltage according to the battery charging time.

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

[0096] In the graph, the Y-axis represents voltage, the X-axis represents time, T1 is the start of charging, T2 is the end of charging, V1 is the battery voltage at the start of charging, and V2 and V3 are the battery voltages at the end of charging. Graph A is the graph corresponding to the first battery charging information, and graph B is the graph corresponding to the second battery charging information.

[0097] The control unit 330 can determine the internal resistance by dividing the change in voltage during the charging period T1-T2 by a 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, 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 shown in Graph B by the second constant current I2.

[0098] The control unit 330 can estimate the internal resistance of the battery by interpolating the first internal resistance R1 and the second internal resistance R2, based on the target initial SOC and 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 due to charging with a target constant current, which has voltage characteristics like graph TA in Figure 7, can be estimated.

[0103] The control unit 330 can also notify the user or transmit this information to the vehicle 100 via the server 200 if the internal resistance of the battery due to charging with a target constant current exceeds a predetermined reference value.

[0104] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modified and improved forms by persons with ordinary skill in the art to which the present invention belongs also fall within the scope of the present invention.

Claims

1. A storage unit for storing multiple battery charge information obtained by multiple constant current charging operations on the battery, A battery internal resistance estimation device including a control unit that reads out multiple battery charge information having the same initial SOC as the target initial SOC from among the multiple battery charge information, determines whether there is any battery charge information corresponding to a constant current that matches the target constant current among the read-out multiple battery charge information, and if it is determined that there is no battery charge information by a constant current that matches the target constant current, estimates the internal resistance of the battery by charging with the target initial SOC and the target constant current using battery charge information corresponding to a constant current adjacent to the target constant current.

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

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

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

5. The control unit, The battery internal resistance estimation device according to claim 2, wherein the device searches for a first backup battery charge 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 charge information read out, and if there are a plurality of first backup battery charge information, the device determines the battery charge information having a battery charge start temperature that is closest to the target battery charge start temperature among the plurality of first backup battery charge information as the first battery charge information.

6. A step of storing multiple battery charge information obtained from multiple constant current charges to the battery, The step of reading out multiple battery charge information from the aforementioned multiple battery charge information, which have the same initial SOC as the target initial SOC, The steps include determining whether, among the multiple battery charging information read out, there is battery charging information corresponding to a constant current that matches the target constant current, A battery internal resistance estimation method, which includes the step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current, using battery charging information corresponding to a constant current adjacent to the target constant current, if it is determined that there is no battery charging information by a constant current that matches the aforementioned target constant current.

7. The step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current is as follows: The steps include determining the first battery charge information corresponding to the first constant current that is larger than the target constant current and is closest to the other among the multiple battery charge information read out, The steps include determining the second battery charge information corresponding to the second constant current that is smaller than the target constant current and is closest to the other among the multiple battery charge information read out, The battery internal resistance estimation method according to claim 6, comprising the step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current using the first battery charge information and the second battery charge information.

8. The step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current using the first battery charge information and the second battery charge information is as follows: A step of determining the first internal resistance of the battery using the first battery charge information, A step of determining the second internal resistance of the battery using the second battery charge information, A battery internal resistance estimation method according to claim 7, comprising the step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current based on the first internal resistance and the second internal resistance.

9. The step of estimating the internal resistance of the battery by charging with the target initial SOC and the target constant current, based on the first internal resistance and the second internal resistance, is: The battery internal resistance estimation method according to claim 8, further comprising the step of interpolating the first internal resistance and the second internal resistance to estimate the internal resistance of the battery by charging with the target initial SOC and the target constant current.

10. The step of determining the first battery charge information corresponding to the first constant current is: The steps include: searching for a first backup battery charge information among the read-out plurality of battery charge information that has a constant current greater than the target constant current and is the closest to it; The battery internal resistance estimation method according to claim 7, further comprising the step of determining, if there are multiple first-prepared battery charge information, the battery charge information having the battery charge start temperature closest to the target battery charge start temperature among the multiple first-prepared battery charge information, as the first battery charge information.

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