CHARGING / DISCHARGING CONTROL DEVICE AND CHARGING / DISCHARGING CONTROL METHOD

Abstract

A charge / discharge control device and a charge / discharge control method are provided that are capable of detecting the influence of a battery degradation factor associated with charging / discharging and suppressing battery degradation. A charge / discharge control device that controls the charging / discharging of a storage battery connected to a load includes: means for setting a reference operating pattern for charging / discharging the storage battery and for calculating a reference degradation level, which is the degradation level of the storage battery in the reference operating pattern; means for calculating an actual operating degradation level, which is the degradation level of the storage battery in an actual operating pattern that differs from the reference operating pattern when charging / discharging the storage battery is carried out in the actual operating pattern;Means for calculating a deterioration magnitude difference, which is a difference between the reference deterioration magnitude and the actual operational deterioration magnitude; and means for calculating a contribution degree of each of several deterioration factors, which are factors of deterioration of the storage battery, based on the deterioration magnitude difference.

Description

Technical field

[0001] The present invention relates to a charging / discharging control device and a charging / discharging control method. background

[0002] In the case of implementing V2H (vehicle-to-home), which connects an electric vehicle (EV) to a home; V2G (vehicle-to-grid), which connects an EV to a power grid; V2L (vehicle-to-load), which connects an EV to an electrical load; V2V (vehicle-to-vehicle), which connects vehicles; or V2X (vehicle-to-everything), which collectively refers to the above techniques and connects an EV to any facility that performs power transfer / receipt, the charging / discharging possibilities of a battery mounted in the EV increase, so that battery degradation is likely to progress.

[0003] Battery degradation largely depends on the operating procedure. It is known that even when operating with the same total charge / discharge volume in the same temperature environment, the extent of degradation varies depending on the cycle depth (which represents the rate of increase / decrease of the battery's state of charge; SOC), the average SOC, the charging time, and other factors. It is necessary to minimize the reduction in battery health (SOH) through appropriate charge / discharge control while the battery is being tested for V2X operation.

[0004] Traditionally, a technique for estimating a relationship between a battery operating pattern and a state of health (SOH) in a case where an operating pattern is not uniform but changes sequentially, as in V2X, is, for example, a technique such as that disclosed in PTL 1 and PTL 2.

[0005] PTL 1 discloses that a storage unit is provided which stores a deterioration curve that indicates a correspondence between a level of use of a battery and a full charge capacity of the battery for each method of use of the battery, the method of use of the battery is determined and, in a case where it is determined that the method of use is changed, the full charge capacity of the battery is estimated by shifting the current deterioration curve of the battery so that the full charge capacity of the deterioration curve before the method of use is changed corresponds to the full charge capacity of the deterioration curve after the method of use has been changed.

[0006] PTL 2 discloses that a prescribed current share distribution, which specifies a current share distribution when a vehicle is driven in each of several pre-stored driving patterns, is stored, and a driving pattern share, which specifies a share of each prescribed current share distribution when an actual current share distribution is represented by a combination of a plurality of several prescribed current share distributions, is derived based on the actual current share in actual operation and the prescribed current share distribution. Citation list for patent literature PTL 1: JP 2020-159990 A PTL 2: JP 2022-144152 A Overview of the invention Technical problem

[0007] Even in a case where the operating pattern is not uniform and changes sequentially, as with V2X, it is necessary to minimize the reduction in battery health (SOH) ("state of health") through appropriate charge / discharge control, while ensuring its role as a battery in an energy storage system within a power grid. It is intended to be used, plays.

[0008] The technique disclosed in PTL 1 requires preparing in advance as many degradation curves for a battery usage method as there are assumed charge / discharge patterns, and it is difficult to manage charge / discharge patterns with a wide variety of charge / discharge patterns ranging from driving to grid connection, as with EVs intended for V2X testing.

[0009] The technique disclosed in PTL 2 adapts to an actual complex charging / discharging pattern by superimposing prescribed current distributions, which specify the current distributions when a vehicle operates in several preset driving patterns. This makes it possible to handle a wide range of driving patterns with a finite, pre-stored pattern. However, the resulting data only reveals one dominant driving pattern, making it difficult to obtain a guideline for suppressing battery degradation.

[0010] As described above, the known patent literature has a problem in that it is not possible to determine the influence of a battery deterioration factor in a case where the operating pattern changes sequentially, and that it is not possible to carry out a suitable operation for long-term suppression of battery deterioration.

[0011] In view of the above problems, one objective of the present invention is to provide a charging / discharging control device and a charging / discharging control method that are able to detect the influence of a battery degradation factor associated with charging / discharging and to suppress the battery degradation. Solution to the problem

[0012] The above description indicates that the present invention provides a charging / discharging control device that controls the charging / discharging of a storage battery connected to a load, wherein the charging / discharging control device includes: means for setting a reference operating pattern for charging / discharging the storage battery and for calculating a reference deterioration level, which is a deterioration level of the storage battery in the reference operating pattern; means for calculating an actual operating deterioration level, which is a deterioration level of the storage battery in an actual operating pattern that differs from the reference operating pattern when the charging / discharging of the storage battery is carried out in the actual operating pattern;Means for calculating a deterioration magnitude difference, which is a difference between the reference deterioration magnitude and the actual operational deterioration magnitude; and means for calculating a contribution degree of each of several deterioration factors, which are factors of deterioration of the storage battery, based on the deterioration magnitude difference.

[0013] Furthermore, the present invention provides a charge / discharge control method for controlling the charging / discharging of a storage battery connected to a load using a computer, wherein the charge / discharge control method comprises: setting a reference operating pattern for charging / discharging the storage battery by the computer and calculating a reference degradation level, which is a degradation level of the storage battery in the reference operating pattern; calculating an actual operating degradation level, which is a degradation level of the storage battery in an actual operating pattern that differs from the reference operating pattern when charging / discharging the storage battery is carried out in the actual operating pattern;Calculating a deterioration magnitude difference, which is a difference between the reference deterioration magnitude and the actual operational deterioration magnitude; and calculating a contribution degree of each of several deterioration factors that are factors of deterioration of the storage battery, based on the deterioration magnitude difference. Advantageous effects of the invention

[0014] According to the present invention, it is possible to accurately and quantitatively determine a change in a battery deterioration factor due to a difference in an operating procedure, and it is possible to suppress battery deterioration in a balanced way by performing a process of applying a load to a battery. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a diagram illustrating an example of an overall configuration with a charging system when a vehicle is V2H connected. [ Fig. 2] Fig. Figure 2 is a diagram illustrating an example of an overall configuration with a charging system when a vehicle is connected via a stationary DC charger using V2H. [ Fig. 3] Fig. Figure 3 is a diagram illustrating an example of a configuration of a charging / discharging control device according to Example 1 of the present invention. [ Fig. 4] Fig. Figure 4 is a diagram illustrating a comparison example of a reference operating pattern and an evaluation target operating pattern. [ Fig. 5] Fig. Figure 5 is a diagram illustrating an example of the extraction of a deterioration factor. [ Fig. 6] Fig. Figure 6 is a diagram illustrating an example of an input / output response of a battery deterioration model. [ Fig. 7] Fig. Figure 7 is a diagram illustrating a base deterioration magnitude, a deterioration magnitude difference, and a contribution degree classification example. [ Fig. 8] Fig. Figure 8 is a flowchart illustrating an example of a control method for a charging / discharging control device according to Example 2 of the present invention. [ Fig. 9] Fig. Figure 9 is a diagram illustrating an example of waveforms of current, voltage, and SOC when operation is performed by setting a battery operating pattern. [ Fig. 10A] Fig. 10A is a graph showing an accumulation visualization result of the battery deterioration factor when operation is performed by setting the battery operating pattern. [ Fig. 10B] Fig. 10B is a graph showing that a load is applied to a battery in terms of cycle depth. [ Fig. 11] Fig. Figure 11 is a diagram showing an example of waveforms of current, voltage and SOC when operation is performed by periodically changing a battery operating pattern. [ Fig. 12A] Fig. 12A is a graph showing an accumulation visualization result of the battery deterioration factor when operation is performed by periodically changing the battery operating pattern. [ Fig. 12B] Fig. 12B is a graph showing that three degradation factors, including cycle depth, charging time and average SOC, are applied to a battery. Description of the embodiments

[0015] In the following, embodiments of the present invention are described with reference to the accompanying drawings. In this description and the drawings, components having essentially the same functions or configurations are designated by the same reference numerals, and repetition is omitted. Example 1

[0016] A charging / discharging control device according to an example of the present invention is described below. Note that in the drawings, the common elements are designated by the same reference numerals.

[0017] Fig. Figure 1 is a hardware diagram of a complete configuration with a charging system when a vehicle is V2H connected. Fig. 1. Electricity is supplied from a power supply system 1 to a household 2, and electricity is supplied from each household 2 to a vehicle 9 equipped with an in-vehicle charger / discharger 10.

[0018] Each household 2 contains a HEMS 3, a distribution board 4, and an external facility 7, and may also include a solar power generation system 5 and a household storage battery 6. Note that this is an example where a vehicle 9, which is an electric vehicle or a plug-in hybrid vehicle, is connected to house 2, assuming a detached house. However, house 2 is not necessarily limited to a detached house where the owner of the vehicle 9 lives. It could, for example, be an apartment building, or a facility equivalent to house 2 could be a business premises or a parking lot. A configuration with multiple vehicles 9 connected is also possible. Note that in a case where it is viewed, for example, from the perspective of an in-vehicle charger / discharger, household 2 can be referred to as an external power source.

[0019] On the other hand, the vehicle 9 includes an in-vehicle charger / discharger 10, a comprehensive controller 15, a battery (HV battery 20, LV battery 21), a power conversion unit 26, and an internal unit 27. Note that the in-vehicle charger / discharger 10 includes an AC charging port 11, a power conversion control unit 12, a battery sensing unit 13, and a power conversion unit 14. The integrated controller 15 includes a network communication unit 16, an ECM 17, an arithmetic operation processing unit 18, and a battery management system (BMS) 19.

[0020] With the installation of such a device, a charging / discharging system charges according to Fig. 1 the battery mounted on the vehicle 9 (HV battery 20, LV battery 21) with power supplied by an external power source (each household 2).

[0021] The following section describes in detail the main components that make up the charging / discharging system. First, the high-voltage (HV) battery 20 is attached to the vehicle 9 and contains a battery module capable of achieving a desired output characteristic by connecting multiple battery cells in series or parallel. Examples of HV batteries 20 include lithium-ion batteries. The low-voltage (LV) battery 21 is used to power an internal 12V system, and examples of this include lead-acid batteries. The HV battery 20 is connected to the power conversion unit 26, and the internal unit 27 utilizes electrical energy as desired. The power conversion unit 26 converts the energy supplied by the HV battery 20 into current and delivers the current to the internal unit 27.

[0022] To determine the condition of the high-voltage battery 20, the battery management system (BMS) 19 includes in its integrated controller 15 a voltage measuring unit capable of determining the voltage of the battery cell, a current measuring unit capable of determining the current flowing through the battery cell, and a temperature measuring unit capable of determining the temperature of the high-voltage battery 20. The voltage measuring unit is designed with a voltage line connecting the battery cells, allowing each cell terminal voltage to be measured individually. For the current measuring unit, one method is to determine the current by measuring the voltage across a shunt resistor Rsht, and a sensor such as a Hall effect sensor can be used. A thermistor, thermocouple, or similar device can be used for the temperature measuring unit.

[0023] As described above, the BMS 19 determines the state of the HV battery 20 by converting its state into a voltage value. Therefore, the BMS 19 can be implemented using a semiconductor device such as a general-purpose analog front-end IC or an ASIC (application-specific integrated circuit). By providing an analog-to-digital converter (ADC), the result obtained by determining the state of the HV battery 20 as a voltage can be converted into a digital value that can be used in an arithmetic processing operation, such as in a program.

[0024] The power conversion unit 26, for example, is a bidirectional inverter and thus drives a traction motor used to propel the vehicle 9. The bidirectional inverter comprises a DC / DC converter unit and an inverter unit. The DC / DC converter unit converts a DC voltage from the HV battery 20 into a voltage required to drive the traction motor, and the inverter unit converts DC current into AC current to control the speed of the traction motor according to its rotational speed, thereby generating torque (drive torque) to accelerate the vehicle. Alternatively, when the vehicle is decelerating, regenerative driving is performed. The vehicle's kinetic energy is recovered as electrical energy, and this electricity is sent via the DC / DC converter unit to the HV battery 20 to charge it.

[0025] The internal device 27, for example, is the drive motor described above and accelerates the vehicle 9 by using electric current as rotational force and regenerates an inertial force of the vehicle 9 as electrical energy by driving the drive motor in cooperation with the bidirectional inverter as a power generator while the vehicle 9 is moving.

[0026] To achieve such operation, the power conversion unit 26 includes a controller (not shown) and sets an output voltage of the DC / DC converter unit by controlling a duty cycle of a switching element of the DC / DC converter unit, and sets a driving force of the traction motor by adjusting a switching frequency and a current phase of the inverter unit. The internal unit 27 is equipped with various sensors for the power conversion unit 26 in order to control the internal unit 27 in a desired manner.

[0027] The power conversion device 26 is also an inverter, which differs, for example, from the bidirectional inverter described above for driving the traction motor, and the internal device 27 is also a compressor drive motor. As a result, an air conditioning system for climate control of the passenger compartment of vehicle 9 is driven.

[0028] This means that the power conversion unit 26 and the internal unit 27 are means for consuming the energy of the HV battery 20, in other words, one of the means for discharging the energy of the HV battery 20, and the vehicle 9 is equipped with several power conversion units 26 and internal units 27. Furthermore, the HV battery 20 is connected to the vehicle's internal charger / discharger 10 and a DC charging port.

[0029] Although Fig. As illustrated by an example where the vehicle's internal charger / discharger 10 is installed with a charging function in the vehicle, it is also possible to use a system where no charging / discharging function is installed in the vehicle. Fig. Figure 2 is a hardware diagram of a complete configuration in a case where the charging function is not installed in the vehicle. As can be seen from the comparison between Fig. 1 and Fig. 2 is clear, is in Fig. 2. Part of the functions of the vehicle's internal charger / discharger 10 as a stationary DC charger 28 are separated, and a DC charging port 29 and the DC-DC converter 25 are newly installed in the vehicle. This difference can be said to be due to a difference in the charging method between AC charging in Fig. 1 and DC charging in Fig. 2 is given.

[0030] As described above, the present invention can be used as a charging method for the charging / discharging system of the vehicle 9, enabling both AC charging via the AC charging port 11 of the vehicle's internal charger / discharger 10 and DC charging via the stationary charger 28 and the DC charging port 29, which are located in Fig. The AC charging and DC charging are handled exclusively by a relay or semiconductor switch (not shown) in the vehicle's onboard charger / discharger 10. The onboard charger / discharger 10 is mounted in the vehicle 9 and bidirectionally converts power supplied by an external power source, such as house 2, and power delivered by the HV battery 20. A stationary charger 28 is installed outside the vehicle 9 and house 2 and bidirectionally converts power supplied by a power source, such as house 2, and power delivered by the HV battery 20.

[0031] During AC charging, the vehicle's internal charger / discharger 10 remains connected to a charging cable via the AC charging port 11, and the charging cable is connected to the distribution board 4 of house 2. One connection method to the distribution board 4 can be a direct connection via a residual current device (RCD) or a connection via an AC socket in house 2. The distribution board 4 is electrically connected to an amperage circuit breaker (not shown) and an electricity meter power supply system 1.

[0032] For DC charging, an AC-DC power conversion unit of the stationary charger 28 is connected via the DC charging port 29, and the stationary charger 28 is connected to the distribution board 4 in house 2. Then, similar to AC charging, an electrical connection is made to the power supply system 1.

[0033] The vehicle's internal charger / discharger 10 contains a DC / DC converter unit capable of converting DC voltage to AC voltage, and a power conversion unit 14 with an inverter unit capable of rectifying AC current from the distribution panel 4 into DC current and converting the DC current output by the DC / DC converter unit into AC current. Furthermore, the power conversion control unit 12, which controls these components, the AC charging port 11, which connects AC current, and the battery sensing unit, which measures battery data from these currents, are included.

[0034] Similar to the vehicle-internal charger / discharger 10, the stationary charger 28 also contains a power conversion unit 14 and a power conversion control unit 12.

[0035] When the HV battery 20 is charged, a so-called CC-CV charging (Constant Current, Constant Voltage) is carried out, which is achieved by combining constant current charging and constant voltage charging according to the battery cells in the HV battery 20.

[0036] In particular, when the charging rate of the HV battery 20 is low, constant current charging is performed, and the charging speed is adjusted so that the current flowing through the battery cell in the HV battery 20 does not exceed a predetermined value. If excessive current flows through the battery cell, lithium ions are not absorbed between the layers of the negative electrode active material in the battery cell, and lithium metal is deposited on the negative electrode, causing an internal short circuit that can lead to thermal runaway accompanied by ignition or rupture of the battery cell. To prevent this situation, it is necessary to control the charging speed, i.e., the current, so that no excessive current flows.

[0037] As the charging of the HV battery 20 progresses and the battery cell voltage increases, the process switches to constant voltage charging. If the battery cell voltage is excessively increased, lithium ions are extracted from the active material of the positive electrode, the electrode structure becomes brittle, and the reactivity of the positive electrode increases. This causes the decomposition reaction of the electrolyte solution to progress, generating gas within the battery cell. This decomposition reaction also generates heat. Since the gas and electrolyte solution generated within the battery cell are flammable, they can ignite, leading to damage such as battery cell ignition or rupture due to an increase in gas pressure. Similar to current, it is necessary to control the voltage to prevent it from becoming excessive.

[0038] Taking the vehicle's internal charger / discharger 10 as an example, the power conversion unit 14 converts the AC current received via the AC charging port 11 into DC current and controls the duty cycle of the switching element of the DC / DC converter unit within the power conversion unit 14, thereby controlling the charging current and charging voltage flowing to the battery cell and ultimately to the high-voltage battery 20. Similarly, in the stationary charger 28, the power conversion unit 14 converts the AC current received via the distribution board 4 into DC current and controls the duty cycle of the switching element of the DC / DC converter unit within the power conversion unit 14, thereby controlling the charging current and charging voltage flowing to the battery cell and ultimately to the high-voltage battery 20.

[0039] As described above, the HV battery 20 can be charged by the vehicle's internal charger / discharger 10 and the stationary charger 28.

[0040] In a case where the power from the HV battery 20 is supplied to house 2, the DC / DC converter unit of the power conversion unit 14 of the vehicle's internal charger / discharger 10 adjusts the voltage according to the AC current used in house 2.

[0041] The inverter unit of the power conversion unit 14 generates an alternating current, thus synchronizing the frequency and phase of the AC current used in house 2. The power conversion control unit 12 sets the duty cycle of a switching signal sent to the switching element of the DC / DC converter unit for voltage adjustment and also sets a switching command for the inverter unit to report back the frequency and phase of the AC current to house 2 and synchronize the frequency and phase to supply power to house 2.

[0042] The same applies to a case in which the current of the HV battery 20 is supplied to the house 2 via the stationary charger 28 and the DC / DC converter unit of the power conversion unit 14, the inverter unit and the power conversion control unit 12 are operated in the same way as the DC / DC converter unit of the power conversion unit 14, the inverter unit and the power conversion control unit 12 of the vehicle's internal charger / discharger 10.

[0043] For example, by enabling the power of the HV battery 20 to be used via the vehicle's internal charger / discharger 10 and the stationary charger 28 in house 2, it is possible to use the power of the HV battery 20 in a case where there is no power supply from the power supply system 1 at the time of a disaster, or to reduce the amount of power purchased from the power supply system 1 in order to reduce the electricity bill of house 2.

[0044] House 2 may still contain a solar power generation system 5 or a fuel cell system (not shown) as a power source to replace the power supply system 1.

[0045] In addition to the solar power generation system 5 described above, the external device 7 is connected to the distribution board 4 of house 2. The external device 7 is a house installation of house 2 or a so-called electrical appliance, and examples of this include an air conditioner for cooling house 2, a hot water supply system, lighting, a cooking appliance, a refrigerator, a white appliance such as a washing machine, a black appliance such as a television and an audio device, as well as an information device such as a personal computer and a telephone.

[0046] Supplying the power from the HV battery 20 to the house 2 via the vehicle's internal charger / discharger 10 or the stationary charger 28 means consuming the energy of the HV battery 20; in other words, it is another means of discharging the energy of the HV battery 20.

[0047] Household 2 contains the Home Energy Management System (HEMS) 3 and can set the time of boiling water in the hot water supply system as an external device 11 according to the operating status and electricity generation quantity of the solar power generation system 5 and the hot water supply system as an external device 11, and can perform the operating status of the air conditioning system as an external device 11, the sale of excess electricity from the solar power generation system 5 to the electricity supply system 1, and the like, according to the electricity demand of house 2 recorded by the electricity meter.The HEMS 3 can be designed to query the power demand of house 2 from outside via a communication module (not shown), and the integrated controller 27 of the vehicle 9 can be designed to capture information such as the power demand of house 2, which is stored by the HEMS 3, via the network communication unit 16 of the vehicle 9.

[0048] The integrated controller 15 contains, as functional blocks, the network communication unit 16, the engine control module (ECM) 17, the arithmetic operation processing unit 18, and the battery management system (BMS). Details of the operation of each functional block of the integrated controller 15 are described later.

[0049] The arithmetic operation processing unit 18 of the integrated controller 15 contains an arithmetic operation unit with a CPU and the like, as well as a memory unit with a memory such as a RAM and a ROM, a recording medium and the like, and implements each functional block of the integrated controller 15 by executing a program stored in the memory unit.

[0050] The integrated controller 15 is designed to be able to detect, as needed, the operating states of the power conversion unit 26 and the internal unit 27, as well as the state of the high-voltage battery 20, and to communicate with the stationary charger 28 via the DC charging port 29. The integrated controller 15 can also communicate via the AC charging port 11 and the charging cable. For communication between the vehicle 9 and the building 2, a communication method such as CAN (Controller Area Network), LIN (Local Interconnect Network), an Ethernet connection, or similar can be used, and there is no problem even if CAN or LIN is used in the vehicle 9 and Ethernet is used for communication in the building 2.Furthermore, communication via PLC (Power Line Communication) or similar technologies can be used. Both wired and wireless communication are possible.

[0051] The configuration case of the charging / discharging system to which the present invention can be applied was described above with reference to the Fig. 1 and Fig. 2 described. Next, a case in which vehicle 9 is stopped and charging from an external power source is discussed will be examined.

[0052] As described above, the known charging method has a problem in that it is not possible to determine the influence of the battery degradation factor in a case where the operating pattern changes sequentially, and it is not possible to implement suitable operation to suppress battery degradation for a long time. Therefore, a method for determining the influence of a battery degradation factor associated with charging / discharging and a degradation suppression method in the charging / discharging control device of the present invention are described here.

[0053] Battery degradation in the HV battery 20 cell progresses primarily through structural changes to the positive and negative electrodes due to charge / discharge cycles. For example, the negative electrode, made of a graphite material, deteriorates due to repeated expansion and contraction associated with the operating environment and charging / discharging. Additionally, the positive electrode, made of a ternary metal material or similar, also deteriorates due to metal corrosion, leaching of a binder, or similar factors. If the same charge / discharge cycle is repeatedly performed during a V2G operation, there is concern that this could lead to an increase in the specific form of deterioration and localized deterioration within the cell.If a specific part of the battery is completely destroyed, the battery's state of health (SOH) deteriorates, even if other parts are healthy, and the battery becomes unusable. While it is necessary to prevent local deterioration within the battery, it is difficult to individually control a deteriorated section. Therefore, the battery's stress is standardized by using an operational deterioration factor as a rating index.

[0054] Fig. Figure 3 is a diagram illustrating an example of the configuration of the charging / discharging control device according to Example 1 of the present invention. The charging / discharging control device according to Example 1 of the present invention is, for example, implemented by the arithmetic operation processing unit 18 in the comprehensive controller 15 in the Fig. 1 and Fig. 2 is implemented or configured in a cloud, and a processing result thereof is stored and used in the comprehensive controller 15 via the network communication unit 16. Note that in the following description, the implementation by the arithmetic operation processing unit 18 is described as an example.

[0055] The processing of the load / unload control device is generally implemented using a computer, but if the processing content is represented as a processing function in the arithmetic operating unit, as in Fig. As shown in Figure 3, the charge / discharge control unit includes processing functions of a battery health (SOH) calculation unit F301, a battery deterioration factor calculation unit F305 and a charge / discharge schedule control unit F316.

[0056] The battery health (SOH) calculation unit F301 includes an external communication unit F302, which receives a deterioration status of the vehicle battery from a deterioration diagnostic device or the like outside the vehicle such as the stationary charger 28, a deterioration diagnostic unit F303, which receives a battery deterioration status from a deterioration diagnostic device of the vehicle such as the in-vehicle charger / discharger 10, and a battery health (SOH) diagnostic unit F304, which estimates the battery health (SOH) based on these information parts.

[0057] The battery deterioration factor calculation unit F305 quantifies the extent of battery deterioration and the contribution of the deterioration factor when the battery is charged and discharged according to a specific target operating pattern. When evaluating a difference in deterioration extent due to two charge / discharge patterns, most of the deterioration extent is accounted for by the reference deterioration extent, which is typically generated regardless of the operating difference. Therefore, a problem arises because the daily deterioration extent difference due to the operating difference is very small, and the contribution calculation described later cannot be performed accurately when the deterioration extent of the target operating pattern is evaluated directly.

[0058] Therefore, in the present invention, the reference operating pattern and the reference deterioration level are defined, and the difference from the deterioration level in the evaluation target operating pattern is taken, thereby improving the extraction accuracy of the change in the battery deterioration factor due to the operating difference.

[0059] Among these, the processing of F306, F307, and F308 for the reference operating pattern is performed. In particular, a reference operating pattern charge / discharge data acquisition unit F306 records in Fig. 3. The current, voltage, and temperature profiles in the reference operating pattern are recorded. Then, a reference deterioration factor calculation unit F307 extracts a characteristic measure related to battery deterioration from the charge / discharge data, and a reference health (SOH) reduction measure calculation unit F308, using the characteristic measure as input and a battery deterioration model, calculates a battery health (SOH) reduction measure at the time of the reference operation. Details of the calculation of the characteristic measure and the health (SOH) reduction measure with respect to battery deterioration are described later.

[0060] Similarly, the processing of F310, F311, and F312 is carried out for the evaluation target operating pattern. In particular, an evaluation target operating pattern load / unload data acquisition unit records F310 in Fig. 3. The current, voltage, and temperature profiles in the evaluation target operating pattern. Then, an operating time deterioration factor calculation unit F311 extracts a characteristic value related to battery deterioration from the charge / discharge data, and an operating time health (SOH) reduction magnitude calculation unit F312 calculates a battery health (SOH) reduction magnitude during the evaluation target operation by using the characteristic magnitude as input.

[0061] Then, an Additional Deterioration Extent Calculation Unit F313 calculates an additional deterioration extent caused by the operating difference by determining the difference between the battery health (SOH) reduction extents for the reference operating pattern and the assessment target operating pattern.

[0062] Then, a deterioration factor sensitivity calculation unit F309 calculates the sensitivity of the deterioration factor using gradient information from the battery deterioration model used to calculate the state of health (SOH) reduction magnitude. Details are described later. A deterioration factor contribution rate calculation unit F314 quantifies the contribution rate of the deterioration factor using the additional deterioration magnitude and the deterioration factor sensitivity described above. A cumulative deterioration factor storage unit F315 collects and stores the calculated deterioration factor contribution rate.

[0063] In the charge / discharge plan control unit F316, an evaluation unit F317 confirms the cumulative deterioration factor accumulation status, determining whether or not the accumulated and stored deterioration factors show a tendency towards a specific factor. A charge / discharge plan correction unit F318 corrects a charge / discharge plan to prevent a tendency towards a specific factor in the accumulation of deterioration factors.

[0064] A comparative example of the reference operating pattern and the target operating pattern is given with reference to Fig. 4 described. Fig. Figure 4 shows the horizontal axis representing 24 hours in a day, and the vertical axis shows, in order from top to bottom, the current, voltage, temperature, and state of charge (SOC). The time series change of the current, voltage, temperature, and SOC levels for the reference operating pattern is shown by a dashed line, and the time series change of the current, voltage, temperature, and SOC levels for the evaluation target operating pattern is shown by a solid line. With respect to current, the positive direction indicates battery charging, and the negative direction indicates discharge to the household side. Note that, for simplicity, a constant-voltage (CV) charging curve for continuous continuous-voltage (CCV) charging is not shown in the current profile.

[0065] According to the case of Fig. In the evaluation target operating pattern represented by the solid line, electricity is purchased at midnight starting at point A at 0:00, and vehicle 9 is charged. Then, the state of charge (SOC) reaches a charging limit at point B, and charging stops. Afterward, house 2 is not supplied with electricity until 6:00 a.m., and the electricity value becomes zero. From point C at 6:00 a.m., the electricity consumption of the heating and cooking appliances in house 2 increases, and therefore electricity is supplied to house 2 from vehicle 9. A driver of vehicle 9 travels from point D to work or the same location, and electricity from the high-voltage battery 20 is consumed by driving. After vehicle 9 finishes driving, it arrives at work or house 2, and the connection to the grid is re-established. From point E, charging with electricity generated by solar power generation 5 begins.The amount of electricity generated by the solar power system varies depending on the season, weather, and location, but it reaches its maximum at point F around midday. As evening approaches, the sun's altitude decreases, the amount of sunlight reaching solar panel 5 at the workplace or house 2 diminishes, and the charging current becomes zero at point G. Then, at point H, the driver leaves the workplace and returns home, and a discharge begins at point I to meet the peak electricity demand at house 2 during the evening and night. This discharge continues until the battery state of charge (SOC) reaches a predetermined lower limit, at which point the charging current becomes zero at point J.

[0066] Furthermore, according to the case of Fig. 4 the reference operating pattern of the dashed line is defined as a representative operating pattern in V2G, and the current profile is determined under the condition of the event as described above.

[0067] The reference operating pattern need not necessarily resemble the target operating pattern. Furthermore, the reference operating pattern need not be an actual measurement, and a result analyzed through simulation can be used.

[0068] Next, the extraction of the feature extent with respect to battery degradation is described. Fig. Figure 5 is a diagram illustrating an example of the deterioration factor extraction. Also in Fig. Figure 5 shows the horizontal axis, similar to in Fig. 4, Fig. The graph displays data for 24 hours in a day, and the vertical axis shows, in order from top to bottom, the current, voltage, temperature, and state of charge (SOC). The state of charge can be calculated by taking time-series data of current, voltage, and temperature as charge / discharge data for the high-voltage battery 20, assuming the battery capacity at that time is known. A deterioration factor parameter is extracted from the data and used as an input parameter for the battery deterioration model.

[0069] Here, as an example of the deterioration factor parameter, the charging time (i.e., the period in which the current value is positive), the discharging time (i.e., the period in which the current value is negative), the average battery temperature, the cycle depth (in which the increase / decrease extent of the SOC is calculated), the upper SOC limit, and the average SOC value are defined.

[0070] Next, the calculation of the health (SOH) decline magnitude and the sensitivity of the deterioration factor using the battery deterioration model is described. Fig. Figure 6 is a diagram illustrating an example of an input / output response of the battery degradation model. Processing using the battery degradation model is represented by the reference SOH reduction magnitude calculation unit F308 and the uptime SOH reduction magnitude calculation unit F312 in [reference missing]. Fig. 3. In processing step S601, the battery degradation factor extracted from the charge / discharge data of HV battery 20 is prepared as an input parameter. Then, in processing step S602, a battery health (SOH) reduction magnitude obtained through operation is calculated using the battery degradation prediction model. Then, in processing step S603, a battery health (SOH) change magnitude (dSOH) is obtained.

[0071] Here, the battery degradation model can be a database that uses the result of a charge / discharge test using an actual battery, or it can be a simulation model. The battery degradation model in this example is a multivariable function with six input parameters, but these parameters are factors that influence the battery's cycle degradation. The degradation caused by these input factors exhibits relatively low nonlinear behavior, and when two parameters are used to indicate a relationship with state of health (SOH), a response curve surface area of ​​30 is obtained for a smooth battery degradation prediction value, as shown in Fig. Figure 6 is shown, drawn. Note that Fig. Figure 6 shows an example of a battery deterioration model in two cases where the input parameters are discharge time and cycle depth, and a relationship between discharge time, cycle depth, and the battery health (SOH) change magnitude dSOH is defined three-dimensionally as a battery deterioration model. The battery deterioration model expresses a difference between the time of the reference operating pattern and the time of the evaluation target operating pattern.

[0072] Partial differentiation of the response curve area 30 of the battery deterioration prediction value with respect to each deterioration factor yields a partial differential coefficient with respect to each factor. The partial differential coefficient corresponds to the gradient of the response curve area, and the larger the gradient, the greater the degree of influence of the deterioration factor. Therefore, the contribution of each deterioration factor is quantified by distributing the difference in deterioration magnitude due to operation based on the ratio of the gradient of each deterioration factor.

[0073] Fig. Figure 7 is a diagram illustrating the basic deterioration level, the deterioration level difference, and an example of the contribution level classification. The basic deterioration level dSOH basein the reference operating pattern on the left side of Fig. Figure 7 is used as a reference, and the degree of deterioration dSOH for the target operating pattern is shown on the right-hand side. The present invention focuses on a degree-of-deterioration difference obtained by taking a difference between the degree of deterioration dSOH and the baseline degree of deterioration dSOH. base takes.

[0074] Furthermore, the magnitude of the influence is quantified for each degradation factor (charge time, discharge time, average battery temperature, cycle depth, upper SOC limit, and average SOC) that contributes to the occurrence of the degradation magnitude difference. This is done by quantifying the magnitude of the influence based on the gradient ratio of the response curve surface 30 in Fig. 6. It is possible to extract the extent of deterioration due to an operational difference with high accuracy and to quantify the strength of the influence for each deterioration factor.

[0075] Note that if fast charging is performed in such a way that the charging current exceeds 1C (1C being the current value at which the capacity of the HV battery 20 can be fully charged in 1 hour), non-linear degradation such as lithium deposition in the battery may occur, and a maximum or minimum value may be generated on the response curve surface 30 of the battery degradation model. To account for the influence of fast charging, it is desirable to create a separate degradation model for fast charging by using a peak current value at the time of charging, a time integral of this value, and the like as input values, and to correct the response curve surface 30 of the battery degradation model accordingly. Example 2

[0076] Example 1 described the charging / discharging control device, but Example 2 describes a charging / discharging control method.

[0077] Fig. Figure 8 is a flowchart illustrating an example of a control method for a charging / unloading device according to Example 2 of the present invention. In this process, a reference operating state and a reference deterioration level, which serve as a baseline, are first calculated in processing step S801. This baseline state is appropriately updated when the vehicle owner changes or when the driver's driving style changes.

[0078] In processing step S802, it is determined whether or not it is time to perform a deterioration diagnosis. The deterioration diagnosis is performed at midnight, 0:00, or a similar time. If the deterioration diagnosis is performed, the deterioration calculation is started using the day's operating data. Specifically, in processing step S803, the deterioration state of the vehicle's own battery is recorded by a deterioration diagnostic device or similar device outside the vehicle, such as the stationary charger 28, or the battery deterioration state is recorded by a deterioration diagnostic device within the vehicle itself, such as the vehicle's in-vehicle charger / discharger 10.

[0079] Then, in processing step S804, a degradation factor is calculated from the operating time charge / discharge data (current, voltage, temperature, and state of charge). In processing step S805, the operating time degradation magnitude and the degradation factor sensitivity are calculated based on the battery degradation model. In processing step S806, the degradation magnitude difference between the operating time and the reference operating time is calculated using the output information from the degradation model. Then, in processing step S807, the degradation magnitude difference is distributed according to the sensitivity ratio of the degradation factors, and the degradation factors are quantified and stored cumulatively.

[0080] Finally, in processing step S808, the next and subsequent charge / discharge schedules are corrected to avoid the accumulation of certain deterioration factors. Processing step S809 determines whether the reference operating pattern should be updated, and processing step S810 determines whether the deterioration accumulation calculation should continue.

[0081] Fig. Figure 9 illustrates simulation waveforms of current, voltage, and state of charge (SOC) when operating by defining a battery operating pattern. A charge / discharge pattern was created assuming a vehicle-to-grid (V2G) environment where vehicle 9 and house 2 were connected. Starting from a fully charged state, a discharge towards the house is initiated at time zero. Charging then occurs via solar power generation. However, the SOC reaches its upper limit during charging, and charging is stopped during this time. A discharge towards house 2 is then performed in the second half of the cycle. In this example, the same charge / discharge pattern was repeated for 30 days.

[0082] Fig. Figure 10A is a graph showing an accumulation visualization result of the battery degradation factor when operation is carried out by defining the battery operating pattern. When the accumulation of degradation factors is calculated based on the method of the present invention, a shape is observed in which the influence of the cycle depth dominates at 98.1% and increases. This shows that the battery capacity decreases due to the degradation of the battery cell, and the magnitude of the change in the battery state of charge (SOC) for each charge / discharge cycle increases by performing the same charge / discharge pattern, regardless of the decrease in battery capacity, thus exerting a load on the battery associated with the cycle depth, as shown in Figure 10A. Fig. 10B is shown.

[0083] Fig. Figure 11 is an example of current, voltage, and state of charge (SOC) waveforms when operation is performed by periodically changing the battery operating pattern. In this case, a charge / discharge schedule is created to periodically change the upper limit SOC during charging and discharging, and the lower limit SOC during discharging, and it can be seen that the time-dependent changes in voltage and SOC are varied.

[0084] Fig. Figure 12A is a graph showing an accumulation visualization result of the battery degradation factors when operation is carried out by periodically changing the battery operating pattern according to the first embodiment of the present invention. By changing the battery operating pattern halfway through (changing the actual operating pattern on the next and subsequent occasions to avoid an accumulation of certain degradation factors), the nature and degree of influence of the accumulated degradation factors are altered, and, as shown in Figure 12A, the battery degradation factors are reduced. Fig. Figure 12B shows that three degradation factors are applied to the battery: cycle depth, charging time, and average state of charge (SOC). As described above, the charge and discharge control is implemented to ensure that the degradation factors accumulate evenly without favoring any one factor, thus suppressing battery degradation.

[0085] The notification regarding the visualization result of the battery degradation factors, as described in the Fig. 10A and Fig. The 12A display can be accessed via an in-vehicle display, the driver's smartphone, or similar device. Furthermore, by simultaneously reporting the recommended charging / discharging control pattern, the user can be prompted to connect the vehicle 9 to the power grid at a suitable time interval, thus enabling ideal charging / discharging control for the vehicle 9 and increasing the utilization rate of the vehicle's in-vehicle battery resources.

[0086] In the present example, the lithium-ion battery was described as an example, but the present invention can also be applied to various batteries, such as solid-state batteries. Similar degradation factor visualization and similar charge / discharge control can be applied to low-voltage batteries, such as lead-acid batteries.

[0087] In the present example, the in Fig.The five factors shown are used as deterioration factors, but a car's mileage, driving time, an integrated value of vehicle vibration, and similar data can also be used as deterioration factors. Furthermore, the battery deterioration model can receive the latest information about the battery through wired or wireless communication outside the vehicle and modify or change the model used for deterioration. It is also possible to exchange model information between batteries of a specific production batch using vehicle-to-vehicle communication, thereby improving accuracy.

[0088] It should be noted that the present invention is not limited to the examples described above and that, of course, various other application examples and modification examples may be considered, as long as the core of the present invention as described in the claims is not altered.

[0089] For example, the embodiment described above describes the configurations of the device in detail and specifically in order to describe the present invention in an easily understandable manner, and is not necessarily limited to those that contain all the described components. With respect to some components in the present examples, other components can also be added, removed, and replaced.

[0090] Control and information lines deemed necessary for the descriptions are shown, but not all control and information lines in the product are necessarily depicted. In practice, it can be assumed that almost all components are interconnected. Reference symbol list 1 Power supply system 2 House 3 HEMS 4 distribution board 5 Solar power generation 6 household storage batteries 7 external institution 9 Vehicle (electric vehicle or plug-in hybrid vehicle) 10 vehicle-integrated charger / discharger 11 AC charging ports 12 Power conversion control unit 13 Battery detection unit 14 Power conversion unit 15 integrated controllers 16 Network communication unit 17 ECM 18 Arithmetic Operation Processing Unit 19 Battery Management System 20 HV battery (high voltage) 21 LV battery (low voltage) 22 AC connection part 25 DC / DC converters 26 Power conversion unit 27 internal device 28 Stationary DC charger 29 DC charging ports 30 Response curve area of ​​the battery deterioration predictor value 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 2020-159990 A

[0006] JP 2022-144152 A

[0006]

Claims

[1] Charging / discharging control device that controls the charging / discharging of a storage battery connected to a load, wherein the charging / discharging control device comprises: Means for setting a reference operating pattern for charging / discharging the storage battery and for calculating a reference deterioration level, which is a deterioration level of the storage battery in the reference operating pattern; Means of calculating an actual operational deterioration extent, which is a deterioration extent of the storage battery in an actual operating pattern that differs from the reference operating pattern when the charging / discharging of the storage battery is carried out in the actual operating pattern; Means of calculating a deterioration magnitude difference, which is a difference between the reference deterioration magnitude and the actual operational deterioration magnitude; and Means of calculating a contribution degree of each of several deterioration factors, which are factors of deterioration of the storage battery, based on the difference in the extent of deterioration. [2] Charging / discharging control device according to claim 1, further comprising means for modifying a subsequent actual operating pattern in order to avoid an accumulation of a particular deterioration factor among the multiple deterioration factors. [3] Charging / discharging control device according to claim 1, wherein the reference operating pattern and the reference deterioration extent are calculated or recorded based on a battery deterioration test or a simulation analysis result. [4] Charging / discharging control device according to claim 1, wherein the deterioration factor includes at least one or more of the following factors: a charging time which is a period during which a current value is positive, a discharging time which is a period during which the current value is negative, an average battery temperature, a cycle depth in which an increase / decrease extent of a SOC is calculated, an upper SOC limit and an average SOC value. [5] Charging / discharging control device according to claim 1, wherein the reference operating pattern and the reference deterioration level are periodically updated based on an operating history and a charging / discharging pattern of a user in the past. [6] Charging / discharging control device according to claim 1, wherein notification of an accumulation status of the deterioration factor and charging / discharging plan-related information such as a recommended EV connection time is provided via an in-vehicle screen or a driver's smartphone. [7] Charging / discharging control method for controlling the charging / discharging of a storage battery connected to a load with a computer, wherein the charging / discharging control method comprises: Establishing a reference operating pattern for charging / discharging the storage battery and calculating a reference degradation level, which is a degradation level of the storage battery in the reference operating pattern; Calculating an actual operational deterioration extent, which is a deterioration extent of the storage battery in an actual operating pattern that differs from the reference operating pattern when charging / discharging the storage battery is performed in the actual operating pattern; Calculating a deterioration magnitude difference, which is a difference between the reference deterioration magnitude and the actual operational deterioration magnitude; and Calculating a contribution level of each of several deterioration factors that are factors of deterioration of the storage battery, based on the difference in the degree of deterioration by the computer. [8] Charging / discharging control method according to claim 7, further comprising modifying a subsequent actual operating pattern to avoid an accumulation of a particular deterioration factor among the multiple deterioration factors.

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