Calculation device for a complete charging capacity and calculation method for a complete charging capacity

Abstract

A full charge capacity calculating device (20) configured to calculate the full charge capacity of a battery (10) comprises: a setting unit (22) configured to set a control lower limit at which the deviation between the open-circuit voltage and the closed-circuit voltage of the battery (10) is corrected, based on the electrical current and temperature of the battery (10); a measuring unit (23) configured to charge the battery (10) in a predetermined section and measure the integrated value of the electrical current in that section when the state of the battery (10) reaches the control lower limit;and a calculation unit (24) configured to calculate the full charging capacity of the battery (10) based on the stored energy of the battery (10) when the control lower limit is reached, and the integrated value of the electric current.;

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to a calculating device for a full charging capacity and a calculating method for a full charging capacity, each calculating the full charging capacity of a battery installed in a vehicle or the like. 2. Description of the related prior art

[0002] Unexamined Japanese patent application No. 2008-261669 (JP 2008-261669 A) discloses a technology for accurately calculating the full charge capacity of a battery without fully discharging or fully charging the battery. The technology calculates the battery's full charge capacity based on a capacity change value of the battery and the rate of change of the state of charge (SOC) during charging from a lower open-circuit voltage (OCV) to an upper open-circuit voltage (OCV). SUMMARY OF THE INVENTION

[0003] JP 2008-261669 A describes a technology that calculates the total charge capacity of a battery based on the open-circuit voltage, which fluctuates with changes in the battery's state of charge. Obtaining the open-circuit voltage is essential. A battery or similar device enclosed in a closed circuit that is constantly connected to an electrical load can obtain a closed-circuit voltage (CCV), but not an open-circuit voltage. The voltage values ​​obtained for an open circuit and a closed circuit differ, leading to the problem that it is not possible to apply the technology according to JP 2008-261669 A to a battery enclosed in a closed circuit or to calculate the total charge capacity.

[0004] The present disclosure relates to a calculating device for a full charging capacity and a calculating method for a full charging capacity for a battery, each of which makes it possible to calculate the full charging capacity even for a battery for which it is not possible to obtain the voltage in an open circuit.

[0005] A device for calculating a full charge capacity according to a first aspect of the present disclosure is configured to calculate the full charge capacity of a battery. The device comprises: a setting unit configured to set a lower control limit based on the battery's electrical current and temperature, correcting the deviation between the open-circuit voltage and the closed-circuit voltage of the battery; and a measuring unit configured to charge the battery in a predetermined section and measure the integrated value of the electrical current in that section.this section measures when the battery's condition reaches the control lower limit; and a calculation unit configured to calculate the battery's full charge capacity based on the battery's stored energy when the control lower limit is reached and the integrated value of the electric current.

[0006] In the calculation device for a full charge capacity according to the first aspect of the present disclosure, the battery can be a lithium-ion battery with a SOC-OCV characteristic that has a flat region in which the rate of change of the open-circuit voltage relative to the stored energy is a predetermined value or less. The setting unit can set the lower control limit in a region that has a stored energy lower than the stored energy of the flat region.

[0007] In the calculating device for a full charging capacity according to the first aspect of the present disclosure, the setting unit can set the lower control limit if the electrical current of the battery is a predetermined electrical current or less and the temperature of the battery is a predetermined temperature or more.

[0008] A method for calculating the full charge capacity of a battery according to a second aspect of the present disclosure comprises: setting a control limit at which the deviation between the voltage in the open circuit and the voltage in the closed circuit of the battery is corrected, based on the electric current and the temperature of the battery; charging the battery in a predetermined section and measuring the integrated value of the electric current in that section when the state of the battery reaches the control limit; and calculating the full charge capacity of the battery based on the energy stored in the battery when the control limit is reached and the integrated value of the electric current.

[0009] The device and method for calculating a full charge capacity according to the present disclosure each perform a processing operation to measure the integrated value of the electric current using the control lower limit, in which the deviation between the open-circuit voltage and the closed-circuit voltage of the battery is corrected. Thus, it is possible to accurately calculate the full charge capacity from the closed-circuit voltage, even for a battery for which it is not possible to obtain the open-circuit voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features, advantages and the technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same symbols denote the same elements, in which the following applies: Fig. Figure 1 is a schematic representation of a calculating device for a complete charging capacity of a battery according to an embodiment of the present disclosure; Fig. 2 is a processing flow diagram that describes a calculation method for a full charging capacity for the battery according to the embodiment of the present disclosure; Fig. Figure 3 is a representation illustrating an example of a SOC-OCV characteristic with a flat region; and Fig. Figure 4 is an example of a two-dimensional characteristic map used to set a lower control limit. DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0011] A full charge capacity calculation device and a full charge capacity calculation method for a battery according to the present disclosure each absorb the deviation between an open-circuit voltage (OCV) and a closed-circuit voltage (CCV) by correcting the voltage values ​​at a control lower limit in a state where the battery has a sufficiently low dark current and a high battery temperature. An embodiment of the present disclosure is described in detail below with reference to the drawings. Example configuration

[0012] Fig. Figure 1 is a functional block diagram illustrating the schematic configuration of a calculation device for a full charging capacity 20 for a battery 10 according to an embodiment of the present disclosure. The in Fig. Figure 1, a calculation device for a full charging capacity, comprises a procurement unit 21, a setting unit 22, a measuring unit 23, and a calculation unit 24. For example, the calculation device for a full charging capacity calculates (estimates) the full charging capacity of battery 10. Battery 10 and the calculation device for a full charging capacity 20 are, for example, installed in a vehicle.

[0013] Battery 10 is a secondary battery configured to be charged and discharged to supply electrical energy to an electrical load 30, such as a piece of equipment or a device. Normally, battery 10 is permanently electrically connected to the electrical load 30. Battery 10 uses a lithium-ion battery (such as an LFP battery) with a state-of-charge-open-circuit voltage (SOC-OCV) characteristic, which has a flat region where the rate of change of the open-circuit voltage (OCV) is proportional to the stored energy (or state of charge), as shown in the diagram. Fig. Figure 3 illustrates a predetermined value or less. Examples for the battery 10 installed in the vehicle include an auxiliary battery that powers the additional electrical load 30.

[0014] Procurement unit 21 is a component that obtains the state of battery 10, such as the voltage in the closed circuit, the current (incoming and outgoing current), the temperature, and the stored energy of battery 10. Procurement unit 21 is capable of obtaining the state of battery 10 from various sensing sensors (not illustrated) provided on battery 10.

[0015] The setting unit 22 is a component that sets a control lower limit for the battery 10. The control lower limit is set as the value of a region with lower stored energy than the stored energy of the flat region of the SOC-OCV characteristic of the battery 10, which is a lithium-ion battery. Specifically, the control lower limit is provided as a voltage value (hereinafter referred to as the "control lower limit") at which the deviation (voltage difference) between the open-circuit voltage (OCV) and the closed-circuit voltage (CCV) is corrected (see Fig. 3) A suitable value for the lower control limit voltage is predetermined depending on various combinations of the electric current and temperature of battery 10. The lower control limit voltage is provided, for example, by a two-dimensional characteristic map shown in Fig. Figure 4 illustrates this. The target current of the battery 10 in the present embodiment is specifically the current (dark current) that flows from the battery 10 to the electrical load 30 in a state (e.g., the state of the vehicle such as ignition off; IG-OFF or Ready-OFF) in which a power supply system is stopped.

[0016] The measuring unit 23 is a component that charges the battery 10 in a predetermined section and measures the integrated value of the electric current in this section (section measurement) when the state of the battery 10 reaches the control lower limit (voltage). Fig. Figure 3 illustrates a section where the measuring unit 23 performs an integration of the electric current. It is possible to use various known techniques to measure the integrated value of the electric current.

[0017] The calculation unit 24 is a component that calculates (estimates) the full charging capacity of the battery 10. The full charging capacity is calculated based on the stored energy of the battery 10 when the battery 10's state reaches the lower control limit (voltage) set by the setting unit 22, and the integrated current value determined by the measuring unit 23 through a sectional measurement.

[0018] The above-described calculation device for a full loading capacity 20 can typically be configured wholly or partially as an electronic control unit (ECU) comprising a processor, memory, an input / output interface, and the like. The electronic control unit performs all or some of the functions of the procurement unit 21, the setting unit 22, the measuring unit 23, and the calculation unit 24 by having the processor read and execute a program stored in memory. steering

[0019] Next, the calculation method for a full load capacity, which is carried out by the calculation device for a full load capacity according to the present embodiment, will be described with reference to the further Fig. 2 described. Fig. Figure 2 is a flowchart illustrating a processing operation of the controller for calculating the full charging capacity for battery 10, which is performed by the respective components of the calculating device for a full charging capacity 20. The in Fig. 2. An exemplary control system for calculating the full charging capacity is started, for example, by detecting a stop in the power supply system, which includes battery 10 as a component, or by receiving a predetermined request. Step S201

[0020] The procurement unit 21 of the calculation device for a full charging capacity procures the electric current (or dark current) and the temperature of battery 10 as the state of battery 10. To procure the electric current and temperature, a current sensor, a temperature sensor and the like (not illustrated) are used.

[0021] When procurement unit 21 procures the current and temperature of battery 10, processing proceeds to step S202. Step S202

[0022] The setting unit 22 of the calculation device for a full charge capacity sets the lower control limit (voltage) of the battery 10 based on the electric current and the temperature of the battery 10. The set lower control limit (voltage) can be determined, for example, by looking up a characteristic map using the values ​​in Fig. 4 two-dimensional maps shown (hatched areas in Fig. 4) be determined. It should be noted that the battery 10 exhibits a larger deviation between the open-circuit voltage (OCV) and the closed-circuit voltage (CCV), and that in the present embodiment, no precise correction can be expected if the battery 10 has too high a current or if the battery 10 has too low a temperature. The lower control limit (voltage) is therefore not set in this way (unshaded areas in Fig. 4) that the control for calculating the full charging capacity of battery 10 is not performed (is masked).

[0023] When the setting unit 22 sets the lower control limit (voltage) of the battery 10, processing proceeds to step S203. Step S203

[0024] The measuring unit 23 of the calculation device for a full charge capacity determines whether the state of battery 10 has reached the control lower limit (voltage). Examples of the state of battery 10 include voltage and stored energy (SOC). In the case of voltage, the voltage is compared with the control lower limit (voltage) to determine the state of charge. In the case of stored energy, the open-circuit voltage (OCV) derived from the SOC-OCV characteristic is compared with the control lower limit (voltage) to determine the state of charge.

[0025] If measuring unit 23 determines that the state of battery 10 has reached the lower control limit (voltage) (Yes in step S203), processing proceeds to step S204. However, if measuring unit 23 determines that the state of battery 10 has not reached the lower control limit (voltage) (No in step S203), the calculation of the full charge capacity for the current battery 10 is terminated. Step S204

[0026] The procurement unit 21 of the calculation device for a full charging capacity procures the closed-circuit voltage (CCV) of battery 10 as the state of battery 10. The closed-circuit voltage serves as the charging start.

[0027] When procurement unit 21 procures the voltage in the closed circuit of battery 10, processing proceeds to step S205. Step S205

[0028] The measuring unit 23 of the full charge capacity calculation device performs a section measurement process in which the battery 10 is charged (or charged and discharged) in a predetermined section, and the integrated value of the electric current in that section (charging section) is measured. The predetermined section can be, for example, any section from a region below the control lower limit of the battery 10 to a region where the flat area of ​​the SOC-OCV characteristic is exceeded and the stored energy (or SOC) is high. The measured integrated value of the electric current is recorded in a predetermined memory or the like (not illustrated).

[0029] When the measuring unit 23 performs the section measurement processing to measure the integrated value of the electric current in the charging section, the processing proceeds to step S206. Step S206

[0030] The calculation unit 24 of the calculation device of a full charge capacity 20 calculates the full charge capacity of the battery 10. The full charge capacity is calculated according to the following (expression 1) from the stored energy (capacity at the time the control lower limit is reached) of the battery 10 when the state of the battery 10 in step S203 reaches the control lower limit (voltage), and from the capacity (integrated current capacity) based on the integrated current value obtained by the section in step S205. Full charging capacity = capacity at the time the lower control limit is reached + integrated capacity of the electric current

[0031] When the full charging capacity of battery 10 has been calculated, the calculation of the full charging capacity of the current battery 10 is complete. Function and effects

[0032] As described above, the calculation device for a full charge capacity 20 and the calculation method for a full charge capacity for the battery 10 according to the embodiment of the present disclosure each define the lower control limit at which the deviation between the open-circuit voltage (OCV) and the closed-circuit voltage (CCV) of the battery 10 is corrected on the basis of the current of the battery 10 and the temperature of the battery 10, charge the battery 10 in a predetermined section defined using the closed-circuit voltage, and measure the integrated value of the electric current in this section when the state of the battery 10 reaches the control limit, and calculate the full charge capacity of the battery 10 from the stored energy of the battery 10 when the control limit is reached.and the capacity based on the integrated value of the electric current.

[0033] As described above, even for a battery 10 for which the open-circuit voltage cannot be obtained, it is possible to accurately calculate (estimate) the full charge capacity of the battery 10 by using a control technique that narrows down scenarios based on the state of the electrical current and the temperature of the battery 10 and corrects the deviation between the open-circuit voltage and the closed-circuit voltage, taking into account the state-of-charge-open-circuit (SOC-OCV) characteristics (battery data) of the battery 10. Furthermore, it is possible to detect the deterioration of the battery 10 by accurately calculating its full charge capacity and thus prevent a reduction in its marketability.

[0034] The embodiment of the present disclosure has been described so far, but the present disclosure is not limited to the above-described calculation device for a full charging capacity and the calculation method for a full charging capacity for the battery. The present disclosure can be understood as a program of the calculation method for a full charging capacity, as a computer-readable, non-transient recording medium that stores the program, as a vehicle in which the calculation device for a full charging capacity is installed, or the like.

[0035] The calculation device for a full charging capacity and the calculation method for a full charging capacity for the battery according to the present disclosure are, for example, usable when it is desirable to accurately estimate the full charging capacity of the battery. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2008-261669 A [0002, 0003]

Claims

A full charge capacity calculating device (20) configured to calculate the full charge capacity of a battery (10), the full charge capacity calculating device (20) comprising: a setting unit (22) configured to set a control lower limit based on the electric current and temperature of the battery (10), correcting any deviation between an open-circuit voltage and a closed-circuit voltage of the battery (10); a measuring unit (23) configured to charge the battery (10) in a predetermined section and measure an integrated value of the electric current in that section when a state of the battery (10) reaches the control lower limit;and a calculation unit (24) configured to calculate the full charging capacity of the battery (10) based on the stored energy of the battery (10) when the control lower limit is reached, and the integrated value of the electric current.; Calculation device of a full charge capacity according to claim 1, wherein: the battery (10) is a lithium-ion battery with a SOC-OCV characteristic having a flat region in which the rate of change of the voltage in the open circuit to the stored energy is a predetermined value or less; and the setting unit (22) sets the control lower limit in a region having a stored energy that is lower than the stored energy of the flat region. Calculation device of a full charging capacity (20) according to claim 1 or 2, wherein the setting unit (22) sets the control lower limit when the electric current of the battery (10) is a predetermined electric current or less and the temperature of the battery (10) is a predetermined temperature or more. Calculation method for a complete charge capacity of a battery (10), wherein the calculation method for a complete charge capacity comprises: setting, based on the electric current and the temperature of the battery (10), a control lower limit at which any deviation between an open-circuit voltage and a closed-circuit voltage of the battery (10) is corrected; charging the battery (10) in a predetermined section and measuring an integrated value of the electric current in that section when a state of the battery (10) reaches the control lower limit; and calculating the complete charge capacity of the battery (10) based on a stored energy of the battery (10) when the control lower limit is reached and the integrated value of the electric current.

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