Deterioration diagnosis method and deterioration diagnosis device

Abstract

To accurately diagnose a state of deterioration of a storage battery.SOLUTION: A deterioration diagnosis device (1) comprises: an analysis unit (21) that performs transient response analysis based on a terminal current and a voltage across terminals during charging or discharging of a storage battery (battery 90), and calculates a series resistance component; a correction unit (22) that corrects the series resistance component at a reference temperature; and a diagnosis unit (23) that diagnoses a state of deterioration of the storage battery based on the corrected series resistance component.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for diagnosing the deterioration of a storage battery. [Background technology]

[0002] There are known technologies for diagnosing the degradation state of a storage battery. As such a conventional technology, a technology that can determine the degradation state from the circuit characteristics when the storage battery is charged and discharged is being considered (see Patent Document 1). Unlike diagnostic technologies that perform test charging and discharging of the storage battery to diagnose the degradation state of the storage battery, this technology does not require the operation of the storage battery to be stopped. On the other hand, a technology that can quickly synthesize an equivalent circuit from the circuit characteristics when the storage battery is charged and discharged is also being considered (see Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-149280 A [Patent Document 2] JP 2013-253784 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to realize a technology that can determine the deterioration state of a storage battery more accurately, in addition to being able to determine the deterioration state of the storage battery from the circuit characteristics during charging and discharging of the storage battery. One aspect of the disclosure of the present invention has been made in consideration of such circumstances, and has an object to realize a deterioration diagnosis method that can accurately determine the deterioration state of a storage battery from the circuit characteristics during charging and discharging of the storage battery. [Means for solving the problem]

[0005] A deterioration diagnosis method according to one embodiment of the present invention includes the steps of measuring the battery temperature, terminal current, and terminal voltage while the battery is being charged or discharged, performing a transient response analysis of the battery based on the terminal current and the terminal voltage, and calculating the series resistance component of the battery at the battery temperature, correcting the series resistance component at the battery temperature to the series resistance component at a predetermined reference temperature, and calculating a capacity decline rate, which is the rate of decline of the storage capacity of the battery relative to the storage capacity in the initial state of the battery, based on the series resistance component at the reference temperature, to diagnose the deterioration state of the battery, wherein the transient response analysis is performed by reducing the battery to an equivalent circuit including a circuit connected in series with the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel.

[0006] A deterioration diagnosis device according to one embodiment of the present invention comprises a measurement unit that measures the battery temperature, terminal current, and terminal voltage while the battery is being charged or discharged; an analysis unit that performs a transient response analysis of the battery based on the terminal current and the terminal voltage, and calculates the series resistance component of the battery at the battery temperature; a correction unit that corrects the series resistance component at the battery temperature to the series resistance component at a predetermined reference temperature; and a diagnosis unit that calculates a capacity decline rate, which is the rate of decline of the storage capacity of the battery relative to the storage capacity in an initial state of the battery, based on the series resistance component at the reference temperature, and diagnoses the deterioration state of the battery, wherein the analysis unit performs the transient response analysis by reducing the battery to an equivalent circuit including a circuit in which the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel are connected in series. Effect of the Invention

[0007] According to the degradation diagnosis method and the degradation diagnosis device of one aspect of the present invention, it is possible to accurately determine the degradation state of a storage battery from the circuit characteristics during charging and discharging of the storage battery. [Brief description of the drawings]

[0008] [Figure 1] 1 is a functional block diagram showing a schematic configuration of a degradation diagnosis device according to a first embodiment of the present invention. [Diagram 2] 4 is a flowchart illustrating the processing steps of a degradation diagnosis method executed by the degradation diagnosis device according to the first embodiment of the present invention. [Diagram 3] 4 is a graph showing example waveforms of a current Ib and a voltage Vb measured by a measurement section of the degradation diagnosis device according to the first embodiment of the present invention. [Figure 4] 3 is an equivalent circuit of a battery applied to a transient response analysis performed by an analysis unit of the degradation diagnosis device according to the first embodiment of the present invention. [Diagram 5] 1 is a graph showing the results of series resistance component Ri calculated by transient response analysis at various temperatures T. Plots with different symbols represent results when the battery degradation state is different. [Figure 6] 1 is a graph showing the dependency of a temperature correction coefficient A on a capacity decrease rate D. [Figure 7] 1 is a graph showing the dependency of a temperature correction coefficient B on a capacity decrease rate D. [Figure 8] 1 is a graph showing the dependency of a temperature correction coefficient C on a capacity decrease rate D. [Figure 9] This is a graph showing plots (squares) showing the relationship between the capacity decay rate D and the series resistance component Ri under conditions where the battery temperature T is fixed, and plots (circles) showing the relationship between the capacity decay rate D and the corrected series resistance component Ri_st. [Figure 10] 1 is a graph showing plots (triangles) showing the relationship between the capacity decay rate D and the series resistance component Ri, and plots (circles) showing the relationship between the capacity decay rate D and the parallel resistance component R1, under the condition that the battery temperature T is fixed. [Figure 11] 6 is a flowchart illustrating the processing steps of a degradation diagnosis method executed by a degradation diagnosis device according to a second embodiment of the present invention. [Figure 12] 4 is an example of an equivalent circuit of a battery applied to a transient response analysis performed by an analysis unit of a degradation diagnosis device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment 1] <Configuration of the Deterioration Diagnostic Device> An embodiment of the present invention will be described in detail below. Fig. 1 is a functional block diagram showing a schematic configuration of a degradation diagnosis device 1 according to an embodiment of the present invention. The degradation diagnosis device 1 is a device that executes a degradation diagnosis method according to an embodiment of the present invention.

[0010] Deterioration diagnosis device 1 monitors battery 90, which is a storage battery, i.e., a secondary battery, and performs deterioration diagnosis of battery 90. Battery 90 is, for example, a lithium ion secondary battery. Deterioration diagnosis device 1 does not need to be a device physically housed in a single housing, so long as each of the functional blocks shown in FIG. 1 and in the following description is realized.

[0011] The degradation diagnosis device 1 includes a measurement unit 10, an arithmetic processing unit 20, and a storage unit 30. The storage unit 30 is a memory that stores information, and may be configured using a magnetic disk, a semiconductor memory, or any other known memory device, either alone or in combination.

[0012] The measurement unit 10 has an ammeter 11 that monitors a current Ib, which is a terminal current flowing between the terminals of the battery 90. In this specification, the current Ib is expressed as a positive value when charging is performed, and the current Ib is expressed as a negative value when discharging is performed. The measurement unit 10 has a voltmeter 12 that monitors a voltage Vb, which is an inter-terminal voltage applied between the terminals of the battery 90.

[0013] The measurement unit 10 also has a thermometer 13 that monitors the temperature T (storage battery temperature) of the battery 90. More specifically, the thermometer 13 may be configured to measure the temperature of the surface of a cell of the battery 90. Alternatively, the thermometer 13 may be configured to measure the temperature of a terminal of the battery 90.

[0014] The value of current Ib measured by ammeter 11 is analog-to-digital converted by AD converter 14 and transmitted as a digital signal to calculation processing unit 20. The value of voltage Vb measured by voltmeter 12 is analog-to-digital converted by AD converter 15 and transmitted as a digital signal to calculation processing unit 20. The value of temperature T measured by thermometer 13 is analog-to-digital converted by AD converter 16 and transmitted as a digital signal to calculation processing unit 20.

[0015] By using the measurement unit 10 having the above-described configuration, the deterioration diagnosis device 1 can measure the temperature T (storage battery temperature), current Ib (terminal current), and voltage Vb (terminal voltage) of the battery 90 while the battery 90 is being charged or discharged.

[0016] The calculation processing unit 20 has the functional blocks of an analysis unit 21, a correction unit 22, a diagnosis unit 23, and a control unit 24. The analysis unit 21 is a functional block that analyzes the current Ib (terminal current) and voltage Vb (terminal voltage) during charging or discharging of the battery 90 (storage battery) measured by the measurement unit 10, and calculates the series resistance component Ri at a temperature T (storage battery temperature).

[0017] The correction unit 22 is a functional block that corrects the series resistance component Ri at temperature T (storage battery temperature) calculated by the analysis unit 21 to a series resistance component Ri_st at a predetermined reference temperature Tst. The diagnosis unit 23 is a functional block that diagnoses a degradation state of the battery 90 (storage battery) based on the series resistance component Ri_st at the reference temperature Tst calculated by the correction unit 22.

[0018] The control unit 24 is a functional block that supervises the arithmetic processing unit 20 and also controls each part of the degradation diagnosis device 1. The operations executed by each functional block of the arithmetic processing unit 20 will be described in detail later.

[0019] <Operation of the deterioration diagnosis device> The degradation diagnosis method, which is a characteristic operation executed by the degradation diagnosis device 1, will be described in detail with reference to Figures 2 to 10. Note that when no unit is indicated on the axis of the graph in each figure, the axis is in an arbitrary unit. Figure 2 is a flowchart showing the degradation diagnosis method executed by the degradation diagnosis device 1 step by step.

[0020] At the start of the degradation diagnosis method, the control unit 24 acquires the current Ib, voltage Vb, and temperature T measured by the measurement unit 10 (step S1). Fig. 3 is a graph showing an example of the waveform of the current Ib detected by the ammeter 11 of the measurement unit 10 and the waveform of the voltage Vb detected by the voltmeter 12. Fig. 3 shows a situation in which a discharge with a temporarily large current value is performed. As shown in the figure, while the discharge is being performed, the voltage Vb gradually decreases.

[0021] Next, based on the acquired waveform data of current Ib and voltage Vb, control unit 24 causes analysis unit 21 to perform a transient response analysis of battery 90 during charging or discharging. At this time, analysis unit 21 performs a transient response analysis of battery 90 during charging or discharging based on the waveforms of current Ib and voltage Vb (step S2).

[0022] In the transient response analysis of the battery 90, the analysis unit 21 treats the battery 90 as an equivalent circuit shown in Fig. 4. The internal equivalent circuit between the terminals of the battery 90 is represented by a circuit in which one or more stages of RC parallel circuits (parallel connection circuits) of a series resistance component Ri, a parallel capacitance component Cn, and a parallel resistance component Rn are connected in series, a series capacitance component Co, and an electromotive force Eo. Here, the electromotive force Eo is the open circuit voltage between the terminals of the battery 90. The symbol n in the parallel capacitance component Cn and the parallel resistance component Rn represents the index of the RC parallel circuit. When the number of stages of the RC parallel circuit is M, the index n is any natural number from 1 to M.

[0023] That is, the internal impedance between the terminals of the battery 90 is represented by a series connection of the impedance of each stage of an RC parallel circuit (parallel connection circuit) consisting of a parallel capacitance component Cn and a parallel resistance component Rn, a series resistance component Ri, and a series capacitance component Co. In step S2, the analysis unit 21 calculates the series resistance component Ri of the battery 90 at temperature T by fitting the waveform data of the current Ib and the voltage Vb to such an equivalent circuit. Note that the number of stages M of the RC parallel circuit may be one, in which case the equivalent circuit is represented as shown in FIG. The parallel resistance component Rn is also a resistance component equivalent to the reaction resistance component of the battery 90. The series capacitance component Co and the electromotive force Eo, which is the open circuit voltage, are values ​​specific to the battery 90 that do not vary depending on the deterioration state of the battery 90, and are stored in advance in the storage unit 30. The correction unit 22 performs the fitting by referring to the values ​​of the series capacitance component Co and the electromotive force Eo stored in the storage unit 30.

[0024] FIG. 5 is a graph showing the results of the calculated series resistance component Ri at various temperatures T of the battery 90. In the deterioration diagnosis device 1, it is preferable to use the temperature immediately before charging or discharging, which is the subject of the transient response analysis, as the temperature T of the battery 90. As shown in FIG. 5, it can be seen that the series resistance component Ri is highly dependent on the temperature T of the battery 90. In addition, in FIG. 5, each plot with a different symbol indicates the results obtained in cases where the deterioration state of the battery 90 is different. The more the deterioration of the battery 90 progresses, the larger the series resistance component Ri becomes. In other words, the result represented by a triangle indicates the most deteriorated state of the battery 90 among the three results in FIG. 5.

[0025] In this specification, the deterioration state of the battery 90 is represented by a capacity decrease rate D, which is the decrease rate of the storage capacity Q of the battery 90 to the storage capacity Qo of the battery 90 in the initial state:

[0026]

number

[0027] Here, the unit of the capacity decrease rate D is percent (%).

[0028] In each plot of FIG. 5, which shows different degradation states, the relationship between temperature T and series resistance Ri can be well approximated by equation (2):

[0029]

number

[0030] The coefficients A, B, and C here are referred to as temperature correction coefficients.

[0031] 6, 7, and 8 are graphs showing the dependence of temperature correction coefficients A, B, and C on capacity decline rate D. As is clear from the figures, temperature correction coefficient A is a parameter that is highly dependent on capacity decline rate D. On the other hand, temperature correction coefficient B is a parameter that is independent of capacity decline rate D, and temperature correction coefficient C has little dependence on capacity decline rate D. Therefore, in equation (2), while temperature correction coefficient A is a function of capacity decline rate D, temperature correction coefficients B and C are considered to be constants that are independent of capacity decline rate D.

[0032] Thus, when considering the series resistance component Ri_st at a certain reference temperature Tst of the battery 90, the temperature correction coefficient A is eliminated from the equation (2) and the series resistance component Ri_st at the reference temperature Tst is expressed by the equation (3):

[0033]

number

[0034] In each formula, the temperature T and the reference temperature Tst are expressed in absolute temperature.

[0035] In this way, the series resistance component Ri_st at the reference temperature Tst can be calculated from the measured series resistance component Ri at a certain temperature T, regardless of the state of deterioration of the battery 90, i.e., even if the capacity degradation rate D is unknown.

[0036] Next, the control unit 24 controls the correction unit 22 to calculate the series resistance component Ri_st at the reference temperature Tst from the series resistance component Ri calculated by the analysis unit 21 based on the acquired temperature T. That is, the correction unit 22 corrects the series resistance component Ri at the temperature T to the value at the reference temperature Tst. The temperature correction coefficients B and C are values ​​determined for each battery 90 and are stored in advance in the storage unit 30. The correction unit 22 refers to the values ​​of the temperature correction coefficients B and C stored in the storage unit 30 and performs the correction according to equation (3) (step S3).

[0037] Next, control unit 24 controls diagnosis unit 23 to cause diagnosis unit 23 to calculate capacity degradation rate D of battery 90 based on series resistance component Ri_st at reference temperature Tst. As described above, capacity degradation rate D is an index that indicates the degradation state of battery 90, and in this way, degradation diagnosis device 1 realizes degradation diagnosis of battery 90 (step S4).

[0038] The plots represented by squares in FIG. 9 show the relationship between the capacity loss rate D and the series resistance component Ri under the condition that the temperature T of the battery 90 is fixed at 25° C. As shown in the figure, it is understood that the capacity loss rate D has a strong dependency on the series resistance component Ri and can be well expressed by a linear equation. In other words, if the series resistance component Ri can be calculated under the condition that the temperature T is constant, the capacity loss rate D can be accurately determined. However, in reality, it is difficult to expect that the current Ib and the voltage Vb will be measured under the condition that the temperature T is constant when the battery 90 is actually operated.

[0039] 9, the temperature T of the battery 90 during measurement is different from 25° C., but the series resistance component Ri_st at the reference temperature Tst obtained by correcting the series resistance component Ri according to the above procedure with the reference temperature Tst set to 25° C. is plotted as a circle. Even in this case, it is understood that the capacity degradation rate D is highly dependent on the corrected series resistance component Ri_st and can be well expressed by a linear equation. In other words, it is clear that the series resistance component Ri is properly corrected to the series resistance component Ri_st at the reference temperature Tst according to the above procedure.

[0040] Therefore, the capacity decay rate D can be accurately estimated by the linear equation (4) using the series resistance component Ri_st at the reference temperature Tst:

[0041]

number

[0042] Here, the constant Rio is a series resistance component at the reference temperature Tst in the initial state, and the coefficient d is referred to as a deterioration correction coefficient.

[0043] The constant Rio and the deterioration correction coefficient d are values ​​determined for each battery 90 and are stored in advance in the storage unit 30. In step S4, the diagnosis unit 23 refers to the values ​​of the constant Rio and the deterioration correction coefficient d stored in the storage unit 30, and calculates the capacity decrease rate D of the battery 90 from the series resistance component Ri_st at the reference temperature Tst according to equation (4).

[0044] According to the formulas (1) to (4), the storage capacity Q of the battery 90 is given by

[0045]

number

[0046] It can be expressed as:

[0047] <Action and effect> According to embodiment 1, the degradation diagnosis device 1 can calculate the capacity degradation rate D, which is an index of degradation of the battery 90, from the circuit characteristics of the battery by monitoring the terminal current (current Ib) and inter-terminal voltage (voltage Vb) of the battery 90 during charging or discharging, and the temperature T of the battery 90.

[0048] Therefore, it is possible to diagnose the deterioration state of the battery 90 without performing a test to obtain the charge capacity by discharging and fully charging the battery 90. Alternatively, it is possible to diagnose the deterioration state of the battery 90 without performing a test to introduce a specific current or apply a specific voltage to the battery 90. Therefore, according to the first embodiment, it is possible to diagnose the deterioration state of the battery 90 while maintaining the operation of the battery 90.

[0049] Moreover, according to the degradation diagnosis method of the first embodiment, the temperature T of the battery 90 is measured and the circuit characteristics (series resistance component Ri) of the battery 90 are corrected, so that it is possible to cancel the strong influence of the temperature T as shown in Fig. 5 and correctly diagnose the degradation state of the battery 90. In particular, in the first embodiment, as shown in formula (3), a clever technique is used that can cancel the influence of the temperature T without being influenced by the degradation state of the battery 90 (capacity decrease rate D), and it is possible to accurately diagnose the degradation state of the battery 90.

[0050] 9, the degradation diagnosis method of the first embodiment is based on the use of a circuit parameter called a series resistance component Ri that can accurately predict the capacity decrease rate D, which is an index showing the degradation state of the battery 90. Therefore, according to the degradation diagnosis method of the first embodiment, it becomes possible to accurately diagnose the degradation state of the battery 90.

[0051] Fig. 10 is a graph showing the relationship between the capacity decrease rate D and the series resistance component Ri or the parallel resistance component R1 (reaction resistance component) under the condition that the temperature T of the battery 90 is kept constant to eliminate the influence of the temperature T. Note that the equivalent circuit used for the transient response analysis is the equivalent circuit shown in Fig. 12, in which the number of stages M of the RC parallel circuit is set to one stage.

[0052] 10, the capacity degradation rate D changes uniformly with respect to the series resistance component Ri, whereas there is a region where the dependency on the parallel resistance component R1 is unclear. In addition, the capacity degradation rate D is expressed by a linear equation for the series resistance component Ri, and the capacity degradation rate D can be predicted with good accuracy over a wide range of the capacity degradation rate D.

[0053] Therefore, in embodiment 1, it can be understood that by representing battery 90 by the equivalent circuit shown in Figure 4 or Figure 10 and extracting a specific component, the series resistance component Ri, with respect to the resistance, it is possible to accurately diagnose the deterioration state of battery 90.

[0054] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0055] Fig. 11 is a flowchart showing a degradation diagnosis method executed by a degradation diagnosis device according to embodiment 2. The degradation diagnosis method according to embodiment 2 is similar to that according to embodiment 1, except that a decision step SJ is added between steps S1 and S2 to branch the flow, compared to the degradation diagnosis method according to embodiment 1 shown in Fig. 2.

[0056] In step SJ following step S1, the control unit 24 determines whether the acquired temperature T is within a required range, i.e., whether the acquired temperature T is equal to or greater than the lower limit temperature T1 and equal to or less than the upper limit temperature T2. If it is determined to be within the required range (YES in step SJ), the flow proceeds to step S2. Otherwise (NO in step SJ), the flow ends.

[0057] In the degradation diagnosis method according to the second embodiment, the deterioration state of the battery 90 is diagnosed only when the acquired temperature T is within a required range, so that the degradation diagnosis can be performed more accurately. Note that the condition for the acquired temperature T being within the required range is not limited to the above example, and the condition may be that the temperature T is equal to or higher than the lower limit temperature T1. Alternatively, the condition may be that the temperature T is equal to or lower than the upper limit temperature T2.

[0058] [Software implementation example] The control block (particularly, arithmetic processing unit 20) of degradation diagnostic device 1 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

[0059] In the latter case, the degradation diagnosis device 1 includes a computer that executes instructions of a program, which is software that realizes each function. This computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. In the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention.

[0060] The processor may be, for example, a CPU (Central Processing Unit). The recording medium may be a "non-transitory tangible medium" such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like. The device may further include a RAM (Random Access Memory) for expanding the program.

[0061] The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or a broadcast wave). Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0062] 〔summary〕 A deterioration diagnosis method according to a first aspect of the present invention includes the steps of measuring the battery temperature, terminal current, and terminal voltage while the battery is being charged or discharged, performing a transient response analysis of the battery based on the terminal current and the terminal voltage, and calculating the series resistance component of the battery at the battery temperature, correcting the series resistance component at the battery temperature to the series resistance component at a predetermined reference temperature, and calculating a capacity decline rate, which is the rate of decline of the storage capacity of the battery relative to the storage capacity in the initial state of the battery, based on the series resistance component at the reference temperature, to diagnose the deterioration state of the battery, wherein the transient response analysis is performed by reducing the battery to an equivalent circuit including a circuit connected in series with the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel.

[0063] The degradation diagnosis method according to aspect 2 of the present invention may be characterized in that, in the step of diagnosing the degradation state of the storage battery in aspect 1 above, the capacity degradation rate is calculated from a linear equation for the series resistance component at the reference temperature.

[0064] A degradation diagnosis method according to aspect 3 of the present invention, in the above-mentioned aspect 1 or 2, may be characterized in that the equivalent circuit further includes a series capacitance component connected in series to the series resistance component and the parallel connection circuit.

[0065] A deterioration diagnosis method according to aspect 4 of the present invention, in any one of aspects 1 to 3 above, may be characterized in that the equivalent circuit includes a circuit in which multiple parallel-connected circuits, in which a parallel capacitance component and a parallel resistance component are connected in parallel, are connected in series.

[0066] A deterioration diagnosis method according to aspect 5 of the present invention, in any of aspects 1 to 4 above, may further include a step of determining whether the battery temperature is within a predetermined range, and if, in the step of determining whether the battery temperature is within a predetermined range, it is determined that the battery temperature is not within the predetermined range, the step of diagnosing the deterioration state of the battery may be not executed.

[0067] A deterioration diagnosis method according to a sixth aspect of the present invention, in any one of the first to fifth aspects above, may be characterized in that, in the step of correcting the series resistance component at the battery temperature to the series resistance component at a predetermined reference temperature, when the battery temperature is expressed as T [K], the reference temperature is expressed as Tst [K], and the series resistance component at the battery temperature T is expressed as Ri, the series resistance component Ri_st at the reference temperature Tst may be calculated from equation (3) using temperature correction coefficients B and C.

[0068] A deterioration diagnosis device according to a seventh aspect of the present invention comprises a measurement unit that measures the battery temperature, terminal current, and terminal voltage while the battery is being charged or discharged; an analysis unit that performs a transient response analysis of the battery based on the terminal current and the terminal voltage, and calculates a series resistance component of the battery at the battery temperature; a correction unit that corrects the series resistance component at the battery temperature to the series resistance component at a predetermined reference temperature; and a diagnosis unit that calculates a capacity decline rate, which is the rate of decline of the storage capacity of the battery relative to the storage capacity in the initial state of the battery, based on the series resistance component at the reference temperature, to diagnose the deterioration state of the battery, wherein the analysis unit performs the transient response analysis by reducing the battery to an equivalent circuit including a circuit in which the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel are connected in series.

[0069] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0070] 1. Deterioration diagnosis device 10 Measuring part 11 Ammeter 12 Voltmeter 13 Thermometer 14, 15, 16 A / D converter 20 Processing section 21 Analysis Department 22 Correction section 23 Diagnostic Department 24 Control Unit 30 Storage section 90 Battery (storage battery) C1~CM, Cn parallel capacitance component Co Series capacitance component Ri series resistance component R1~RM, Rn parallel resistance component Eo electromotive force (open circuit voltage) Ib current (terminal current) Vb Voltage (Terminal voltage) T temperature (storage battery temperature) Tst reference temperature Ri_st Series resistance component at reference temperature D Capacity reduction rate

Claims

1. measuring the battery temperature, terminal current and terminal voltage while the battery is being charged or discharged; performing a transient response analysis of the storage battery based on the terminal current and the terminal voltage, and calculating a series resistance component of the storage battery at the storage battery temperature; correcting the series resistance component at the storage battery temperature to the series resistance component at a predetermined reference temperature; and calculating a capacity decrease rate, which is a decrease rate of the storage capacity of the storage battery relative to the storage capacity in an initial state of the storage battery, based on the series resistance component at the reference temperature, to diagnose a deterioration state of the storage battery; The transient response analysis is performed by reducing the storage battery to an equivalent circuit including a circuit connected in series to the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel; determining whether the battery temperature is within a predetermined range; When it is determined in the step of determining whether the battery temperature is within a predetermined range that the battery temperature is not within the predetermined range, A deterioration diagnosis method, comprising the step of diagnosing the deterioration state of the storage battery being omitted.

2. A step of measuring a battery temperature, a terminal current, and a terminal voltage while the battery is being charged or discharged; performing a transient response analysis of the storage battery based on the terminal current and the terminal voltage, and calculating a series resistance component of the storage battery at the storage battery temperature; correcting the series resistance component at the storage battery temperature to the series resistance component at a predetermined reference temperature; and calculating a capacity decrease rate, which is a decrease rate of the storage capacity of the storage battery relative to the storage capacity in an initial state of the storage battery, based on the series resistance component at the reference temperature, to diagnose a deterioration state of the storage battery; The transient response analysis is performed by reducing the storage battery to an equivalent circuit including a circuit connected in series to the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel; In the step of correcting the series resistance component at the storage battery temperature to the series resistance component at a predetermined reference temperature, A deterioration diagnosis method, characterized in that, when the battery temperature is expressed as T [K], the reference temperature is expressed as Tst [K], and the series resistance component at the battery temperature T is expressed as Ri, the series resistance component Ri_st at the reference temperature Tst is calculated from the following formula (E1) using temperature correction coefficients B and C. [0010]

3. In the step of diagnosing a deterioration state of the storage battery, 3. The degradation diagnosis method according to claim 1, wherein the capacity decrease rate is calculated from a linear equation for the series resistance component at the reference temperature.

4. 4. The degradation diagnosis method according to claim 1, wherein the equivalent circuit further includes a series capacitance component connected in series to the series resistance component and the parallel connection circuit.

5. 5. The degradation diagnosis method according to claim 1, wherein the equivalent circuit includes a circuit in which a plurality of parallel-connected circuits, in which a parallel capacitance component and a parallel resistance component are connected in parallel, are connected in series.

6. A measurement unit for measuring a battery temperature, a terminal current, and a terminal voltage while the battery is being charged or discharged; an analysis unit that performs a transient response analysis of the storage battery based on the terminal current and the inter-terminal voltage and calculates a series resistance component of the storage battery at the storage battery temperature; a correction unit that corrects the series resistance component at the storage battery temperature to the series resistance component at a predetermined reference temperature; a diagnosis unit that calculates a capacity decrease rate, which is a decrease rate of a storage capacity of the storage battery relative to a storage capacity in an initial state of the storage battery, based on the series resistance component at the reference temperature, and diagnoses a deterioration state of the storage battery; The analysis unit reduces the storage battery to an equivalent circuit including a circuit in which the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel are connected in series, and performs the transient response analysis; a control unit that determines whether the battery temperature measured by the measurement unit is within a predetermined range; A deterioration diagnosis device characterized in that, when the control unit determines that the battery temperature measured by the measurement unit is not within the specified range, the diagnosis unit does not diagnose the deterioration state of the battery.

7. A measurement unit for measuring a battery temperature, a terminal current, and a terminal voltage while the battery is being charged or discharged; an analysis unit that performs a transient response analysis of the storage battery based on the terminal current and the inter-terminal voltage and calculates a series resistance component of the storage battery at the storage battery temperature; a correction unit that corrects the series resistance component at the storage battery temperature to the series resistance component at a predetermined reference temperature; a diagnosis unit that calculates a capacity decrease rate, which is a decrease rate of a storage capacity of the storage battery relative to a storage capacity in an initial state of the storage battery, based on the series resistance component at the reference temperature, and diagnoses a deterioration state of the storage battery; The analysis unit reduces the storage battery to an equivalent circuit including a circuit in which the series resistance component and a parallel connection circuit in which a parallel capacitance component and a parallel resistance component are connected in parallel are connected in series, and performs the transient response analysis; a correction unit that calculates the series resistance component Ri_st at the reference temperature Tst from the following formula (E1) using temperature correction coefficients B and C, when the battery temperature is expressed as T [K], the reference temperature is Tst [K], and the series resistance component at the battery temperature T is expressed as Ri: [0025]

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