Management device, power storage device, and voltage simulation method

Abstract

A management device (130) that periodically executes voltage simulation of a power storage device (50) includes a calculation unit (131) and a storage unit (132). The storage unit (132) stores a discharge pattern (P) comprising time-series data of the discharge current. The discharge pattern (P) includes first time-series data (D1) of the discharge current and second time-series data (D2) of the discharge current, the first time-series data (D1) being time-series data of an amount of the discharge current for a predetermined time, and the second time-series data (D2) being time-series data of the discharge current during a voltage simulation execution cycle of the power storage device. The calculation unit (131) periodically executes a voltage simulation that estimates a change in voltage of the power storage device (50) when the power storage device is discharged in the discharge pattern (P), and periodically determines, on the basis of the result of the voltage simulation, whether or not the power storage device can be discharged in the discharge pattern (P).

Description

Technical Field

[0001] The present invention relates to voltage simulation of an electric storage device. Background Art

[0002] Power storage devices are used in various applications, such as power sources for mobile vehicles represented by automobiles and power storage for solar power generation systems (see Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-5985

[0006] Patent Document 2: Japanese Patent Application Publication No. 2019-126110 Summary of the invention

[0007] Problems to be solved by the invention

[0008] One of the functions of a power storage device is voltage simulation. Voltage simulation estimates the voltage change of the power storage device when discharging in a predetermined discharge pattern. For example, in the case of a power storage device for an automobile, the result of voltage simulation is used to determine whether discharge based on the discharge pattern can be performed.

[0009] By periodically executing the voltage simulation, it is possible to periodically check whether discharge in the discharge mode is possible. The voltage simulation is not limited to automobiles, but can also be applied to other uses such as power storage in a solar power generation system.

[0010] However, if the power storage device is discharged during the execution cycle of the voltage simulation, there is a possibility that an erroneous determination is made as to whether the discharge is possible.

[0011] An object of the present invention is to suppress erroneous determination of whether or not discharge can be performed based on a discharge pattern.

[0012] Means for solving problems

[0013] An overview of the management device is described.

[0014] The management device is a device that periodically performs voltage simulation of the power storage device. The management device includes a calculation unit and a storage unit. The voltage simulation of the power storage device may be a voltage simulation of an external terminal or a voltage simulation of a battery cell or a battery pack.

[0015] The storage unit stores a discharge pattern composed of time series data of a discharge current. The discharge pattern includes first time series data and second time series data of the discharge current. The first time series data is time series data of a predetermined time amount of the discharge current, and the second time series data is time series data of the discharge current within a voltage simulation execution cycle of the power storage device.

[0016] The calculation unit periodically executes a voltage simulation for estimating a voltage change of the power storage device when the power storage device is discharged in the discharge mode, and periodically determines whether the power storage device can be discharged in the discharge mode based on a result of the voltage simulation.

[0017] The present technology can be applied to a voltage simulation method and a voltage simulation program.

[0018] Effects of the Invention

[0019] This technology can suppress erroneous determination of whether or not discharge can be performed based on the discharge pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a side view of the car.

[0021] Figure 2 It is an exploded perspective view of a battery.

[0022] Figure 3 It is a top view of a secondary battery cell.

[0023] Figure 4 yes Figure 3 AA line cross-section diagram.

[0024] Figure 5 This is a block diagram showing the electrical structure of a battery.

[0025] Fig. 6A This is the waveform of the discharge mode before improvement.

[0026] Figure 6B This is the waveform of the improved discharge mode.

[0027] Figure 7 is the timeline of the voltage simulation.

[0028] Figure 8 It is the voltage estimation result based on voltage simulation.

[0029] Fig. 9 It is the voltage estimation result based on voltage simulation.

[0030] Fig.10 This is a diagram showing input and output to the calculation unit.

[0031] Fig.11 It is a diagram showing the execution cycle of the voltage simulation.

[0032] Fig. 12A is the waveform of the first discharge mode.

[0033] Fig. 12B is the waveform of the second discharge mode.

[0034] Fig.13 It is the flow chart of voltage simulation.

[0035] Fig.14 This is a diagram showing input and output to the calculation unit. DETAILED DESCRIPTION

[0036] An overview of the management device is described.

[0037] (1) A management device according to one embodiment of the present invention is a device that periodically performs voltage simulation of a power storage device. The management device includes a calculation unit and a storage unit.

[0038] The storage unit stores a discharge pattern composed of time series data of a discharge current. The discharge pattern includes first time series data and second time series data of the discharge current. The first time series data is time series data of a predetermined time amount of the discharge current, and the second time series data is time series data of the discharge current within a voltage simulation execution cycle of the power storage device.

[0039] The calculation unit periodically executes a voltage simulation for estimating a voltage change of the power storage device when the power storage device is discharged in the discharge mode, and periodically determines whether the power storage device can be discharged in the discharge mode based on a result of the voltage simulation.

[0040] According to the management device described in (1), the discharge pattern includes second time series data in addition to the first time series data of the discharge current. The second time series data is time series data of the discharge current of the power storage device during the voltage simulation execution cycle, so that voltage simulation can be performed taking into account the discharge during the execution cycle.

[0041] Therefore, it is possible to suppress a situation in which it is erroneously determined that the power storage device can discharge in the discharge mode even though the power storage device actually has no remaining power to discharge in the discharge mode due to the discharge in the execution cycle.

[0042] (2) In the management device described in (1) above, the execution cycle of the voltage simulation may be switchable. According to the management device described in (2) above, by shortening the execution cycle, the judgment cycle of whether discharge is possible is shortened, so that when the power storage device changes from a state in which discharge is possible to a state in which discharge is not possible, the situation can be discovered as early as possible. By extending the execution cycle, the calculation load of the calculation unit can be reduced, thereby achieving energy saving.

[0043] (3) In the management device described in (2), the power storage device may be used in a vehicle. According to the management device described in (3), the operation unit may perform voltage simulation in a first cycle when the vehicle is in a first state, and perform voltage simulation in a second cycle when the vehicle is in a second state. In this structure, the accuracy of determining whether discharge is possible can be switched according to the state of the vehicle.

[0044] (4) In the management device described in (3) above, the first state may be that the vehicle is traveling, the second state may be that the vehicle is not traveling, and the second cycle may be longer than the first cycle. According to the management device described in (4) above, the voltage simulation is performed in the first cycle (short cycle) while the vehicle is traveling, so that when the power storage device reaches a state where it cannot discharge based on the discharge mode, this situation can be discovered as early as possible. On the other hand, when the vehicle is not traveling, the voltage simulation is performed in the second cycle (long cycle), so that the power consumption of the management device can be suppressed, thereby achieving energy saving.

[0045] (5) In the management device described in (3) or (4) above, the second time series data may be different depending on the state of the vehicle. According to the management device described in (5) above, the voltage simulation is performed using the second time series data corresponding to the state of the vehicle, so that the estimation error of the discharge current within the execution cycle of the voltage simulation can be suppressed. Therefore, a voltage simulation with high accuracy can be performed.

[0046] (6) In the management device described in (5) above, the first state may be that the vehicle is traveling, and the second state may be that the vehicle is not traveling. The second time series data when the vehicle is not traveling may be smaller than the second time series data when the vehicle is traveling. According to the management device described in (5) above, when the vehicle is traveling with a large discharge, the value of the second time series data is increased, and when the vehicle is not traveling with a small discharge, the value of the second time series data is decreased, thereby reducing the error of the discharge current (the error between the actual discharge current and the simulated discharge current).

[0047] (7) In the management device described in any one of (2) to (6) above, the storage unit may store a first discharge pattern having time series data for a first cycle and a second discharge pattern having time series data for a second cycle as the execution cycle of the voltage simulation. The operation unit may select the first discharge pattern to execute the voltage simulation when the first cycle is selected, and select the second discharge pattern to execute the voltage simulation when the second cycle is selected. According to the management device described in (7) above, the discharge pattern is set for each cycle, so the accuracy of the voltage simulation is high regardless of the difference in the cycle. Therefore, the accuracy of determining whether discharge based on the discharge pattern can be performed can be further improved.

[0048] (8) In the management device described in any one of (1) to (7) above, the calculation unit may estimate the voltage change of the power storage device based on the SOC of the power storage device, the internal resistance of the battery cell, the discharge current, the temperature of the battery cell, and the charge and discharge history. According to the management device described in (8) above, a voltage simulation is performed that takes into account the voltage change caused by the SOC change, the internal resistance, the temperature, and the charge and discharge history, thereby improving the accuracy of voltage estimation and the accuracy of determining whether power supply can be performed.

[0049] (9) In the management device described in any one of (1) to (8), the calculation unit may perform a plurality of voltage simulations in parallel using a plurality of discharge patterns. The management device described in (9) can determine whether discharge based on a plurality of discharge patterns is possible.

[0050] (10) A power storage device according to one embodiment of the present invention includes a battery cell and the management device described in any one of (1) to (9). The management device described in (10) can be executed by a management device having a built-in voltage simulation based on a discharge mode.

[0051] <Implementation method 1>

[0052] 1. Description of the battery 50

[0053] like Figure 1 As shown, the vehicle 10 is equipped with an engine 20 and a battery 50. The battery 50 is used as an auxiliary machine of the vehicle 10. The battery 50 is an example of a "power storage device". The vehicle 10 may also be equipped with a power storage device for driving the vehicle or a fuel cell.

[0054] like Figure 2As shown, the storage battery 50 includes a battery pack 60, a circuit board unit 65, and a storage body 71. The storage body 71 includes a main body 73 made of a synthetic resin material and a cover 74. The main body 73 is a bottomed cylindrical shape, and includes a bottom portion 75 and four side portions 76. An opening portion 77 is formed at the upper end of the main body 73 by the four side portions 76.

[0055] The storage body 71 stores the battery pack 60 and the circuit board unit 65. The circuit board unit 65 is a circuit board 100 on which various components (current interruption device 53, Figure 5 The current detection unit 54, the management device 130, etc. shown in FIG. Figure 2 As shown, it is arranged adjacent to, for example, the upper side of the battery pack 60. Alternatively, the circuit board unit 65 may be arranged adjacent to the side of the battery pack 60.

[0056] The cover 74 closes the opening 77 of the main body 73. An outer peripheral wall 78 is provided around the cover 74. The cover 74 has a protrusion 79 that is substantially T-shaped when viewed from above. In the front part of the cover 74, the positive external terminal 51 is fixed at one corner, and the negative external terminal 52 is fixed at the other corner. Instead of the main body 73 of the storage body 71, the circuit substrate unit 65 may be stored in the cover 74 (for example, in the protrusion 79).

[0057] The battery pack 60 is composed of a plurality of battery cells 62. Figure 4 As shown, the battery cell 62 contains an electrode body 83 and a non-aqueous electrolyte in a rectangular parallelepiped (prism-shaped) case 82. The battery cell 62 is, for example, a lithium-ion secondary battery cell. The case 82 has a case body 84 and a cover 85 that closes an opening on the top thereof.

[0058] The electrode body 83 is not shown in detail, and is obtained by disposing a separator made of a porous resin film between a negative electrode plate obtained by coating an active material on a substrate composed of copper foil and a positive electrode plate obtained by coating an active material on a substrate composed of aluminum foil. They are all strip-shaped, and the negative electrode plate and the positive electrode plate are respectively offset on opposite sides of the width direction relative to the separator, and are wound into a flat state so that they can be accommodated in the shell body 84. The electrode body 83 can also be a stacked type instead of a wound type.

[0059] The positive terminal 87 is connected to the positive electrode plate via the positive electrode collector 86, and the negative terminal 89 is connected to the negative electrode plate via the negative electrode collector 88. The positive electrode collector 86 and the negative electrode collector 88 have a flat base portion 90 and a leg portion 91 extending from the base portion 90. A through hole is formed in the base portion 90. The leg portion 91 is connected to the positive electrode plate or the negative electrode plate.

[0060] The positive terminal 87 and the negative terminal 89 are composed of a terminal body 92 and a shaft 93 protruding downward from the center of the lower surface thereof. The terminal body 92 and the shaft 93 of the positive terminal 87 are integrally formed of aluminum (a single material). In the negative terminal 89, the terminal body 92 is made of aluminum and the shaft 93 is made of copper, and they are combined. The terminal bodies 92 of the positive terminal 87 and the negative terminal 89 are arranged at both ends of the cover 85 via gaskets (gaskets) 94 made of insulating material, such as Figure 3 As shown, the gasket 94 is exposed outward.

[0061] The cover 85 has a pressure release valve 95. The pressure release valve 95 is located between the positive electrode terminal 87 and the negative electrode terminal 89. The pressure release valve 95 is a safety valve. The pressure release valve 95 opens when the internal pressure of the case 82 exceeds a limit to reduce the internal pressure of the case 82.

[0062] Figure 5 1 is a block diagram showing the electrical configuration of the storage battery 50 . The storage battery 50 includes a battery pack 60 , a current detection unit 54 , a current interruption device 53 , a voltage detection unit 110 , a temperature sensor 58 , and a management device 130 .

[0063] A vehicle ECU (Electronic Control Unit) 140 , an AC generator 150 as a generator that generates electricity using the power of the engine 20 , and an auxiliary machine 160 of the automobile 10 are electrically connected to the battery 50 . The vehicle ECU 140 is a vehicle control unit that controls the automobile 10 .

[0064] The vehicle ECU 140 controls the alternator 150 and the auxiliary machine 160. The vehicle ECU 140 may also control a drive system such as an engine. The vehicle ECU 140 is not limited to one, and may be a plurality of vehicles.

[0065] The auxiliary device 160 includes a specific load 160A and a general load 160B. The specific load 160A is a target load for voltage simulation described later. The general load 160B includes, for example, a headlight, a wiper, a car navigation system, an air conditioner, and the like.

[0066] When the power generation of the alternator 150 is greater than the power consumption of the auxiliary machine 160 during the driving of the engine 20, the battery 50 is charged by the alternator 150. When the power generation of the alternator 150 is less than the power consumption of the auxiliary machine 160, the battery 50 is discharged to make up for the shortfall.

[0067] When the engine 20 is stopped, the alternator 150 stops generating electricity. When the power generation is stopped, the battery 50 is not charged and is only discharged to the vehicle ECU 140 and the auxiliary machine 160.

[0068] The battery pack 60 includes, for example, 12 battery cells 62 (see Figure 2 ), connected in series with 3 in parallel and 4 in series. Figure 5 In the figure, three battery cells 62 connected in parallel are represented by one battery symbol. The battery cell 62 is an example of a "power storage battery cell".

[0069] The storage battery cell is not limited to a prismatic battery cell, and may be a cylindrical battery cell or a pouch-shaped battery cell having a laminated film case. The storage battery 50 is rated at 12V.

[0070] The battery pack 60, the current interruption device 53, and the current detection unit 54 are connected in series via the power lines 55P and 55N. The power lines 55P and 55N can use a bus bar BSB (see FIG. 1 ) which is a plate-shaped conductor made of a metal material such as copper. Figure 2 ).

[0071] like Figure 5 As shown, the power line 55P connects the positive external terminal 51 to the positive electrode of the battery pack 60. The power line 55N connects the negative external terminal 52 to the negative electrode of the battery pack 60. The external terminals 51 and 52 are terminals for connecting the battery 50 to the automobile 10 (auxiliary machine 160). The battery 50 can be electrically connected to the alternator 150 and the auxiliary machine 160 via the external terminals 51 and 52.

[0072] The current interruption device 53 is provided on the positive power line 55P. The current interruption device 53 may be a semiconductor switch such as FET or a relay having mechanical contacts. The current interruption device 53 is preferably a self-holding switch such as a latch relay.

[0073] The current cutoff device 53 is of a normally closed type and is controlled to be in a closed state in normal conditions. When the storage battery 50 has some abnormality, the current of the battery pack 60 can be cut off by switching the current cutoff device 53 from the closed state to the open state.

[0074] The current detection unit 54 is provided on the negative power line 55N. The current detection unit 54 may also be a shunt resistor. The resistive current detection unit 54 can measure the current I of the battery pack 60 based on the voltage Vr across the current detection unit 54. The resistive current detection unit 54 can distinguish between discharge and charge according to the polarity (positive and negative) of the voltage. Alternatively, the current detection unit 54 may also be a magnetic sensor.

[0075] The voltage detection unit 110 can detect the voltage Vs of the battery cell 62 and the total voltage Vt of the battery pack 60. The temperature sensor 58 is mounted on the battery pack 60 and detects the battery temperature TS of the battery pack 60 or the temperature TS of its surroundings.

[0076] The management device 130 is actually mounted on the circuit board 100 (see Figure 2 ) Figure 5 As shown, a computing unit 131 such as a CPU, a storage unit 132 and a communication unit 133 are provided.

[0077] The communication unit 133 is connected to the vehicle ECU 140 via a signal line and communicates with the vehicle ECU 140. The management device 130 can receive a signal related to the operating state of the automobile 10 (driving, temporarily stopped, parked, etc.) from the vehicle ECU 140 through communication.

[0078] The management device 130 monitors the state of the storage battery 50 based on the outputs of the voltage detection unit 110, the current detection unit 54, and the temperature sensor 58. In other words, the management device 130 monitors the battery temperature TS, the current I, and the total voltage Vt of the battery pack 60.

[0079] The management device 130 estimates the SOC [%] of the battery pack 60 based on the current I of the battery pack 60 .

[0080] SOC (state of charge) is the ratio of the remaining capacity to the full charge capacity, and is expressed by the following formula (1).

[0081] SOC=(Cr / Co)×100···········(1)

[0082] Co is the full charge capacity of the battery cell, and Cr is the remaining capacity of the battery cell.

[0083] As shown in the following formula (2), the SOC can be estimated based on the time-integrated value of the current I. It is assumed that the sign of the current I is positive during charging and negative during discharging.

[0084] SOC=SOCo+100×(∫Idt / Co) ··· (2)

[0085] SOCo is the initial value of SOC, and I is the current.

[0086] The storage unit 132 stores a voltage simulation execution program and data required for executing the program. The data stored in the storage unit 132 includes data of a discharge pattern P described later. In addition, the data includes data of the internal resistance R of the battery pack 60 and data of the charge and discharge history of the storage battery 50 .

[0087] The program may be stored in a recording medium such as a CD-ROM and used, transferred, loaned, etc. The program may also be distributed using telecommunication lines.

[0088] 2. Voltage simulation

[0089] In the voltage simulation, the discharge pattern P is used to estimate the temporal change of the total voltage Vt of the battery pack 60 .

[0090] The discharge pattern P is the first time series data D1 of the amount of discharge current for a specified time. For example, Fig. 6A The discharge pattern P is the data of the discharge current for 12 seconds defined by a graph with time as the horizontal axis and the discharge current as the vertical axis. As an example, the discharge pattern P is the discharge current required for the operation of the specific device 160A. When the operation time of the specific device 160A is 12 seconds, the discharge pattern P is the data for 12 seconds.

[0091] The voltage simulation obtained the total voltages Vt0 to Vt12 when the storage battery 50 is discharged for 12 seconds according to the discharge pattern P, that is, when the storage battery 50 is discharged for 12 seconds to the specific device 160A.

[0092] By comparing total voltages Vt0 to Vt12 with lower limit voltage VL of total voltage Vt, it is possible to determine whether battery 50 can discharge in discharge mode P, that is, whether power sufficient to operate specific load 160A can be supplied to specific load 160A.

[0093] Figure 7 is the timeline of the voltage simulation, Figure 8 is the simulation result. Figure 8 According to the simulation result, since the total voltages Vt0 to Vt12 are equal to or higher than the lower limit voltage VL, in this case, it is determined that the battery 50 can be discharged in the discharge mode P, that is, can supply power to the specific load 160A (the specific load 160A can operate).

[0094] On the other hand, when part of total voltages Vt0 to Vt12 is lower than lower limit voltage VL (Vt<VL), it is determined that discharge in discharge mode P is impossible, that is, power cannot be supplied to specific load 160A (specific load 160A cannot operate).

[0095] like Figure 7 As shown, by periodically executing the voltage simulation (t1, t2, t3, ...), it is possible to periodically check whether discharge in the discharge pattern P is possible.

[0096] When discharge in discharge mode P is not possible, battery 50 can be returned to a state where it can supply power to specific load 160A by prompting vehicle ECU 140 to charge.

[0097] As an example, the specific load 160A is a safety-related load such as an electric brake and an electric steering gear. In this embodiment, voltage simulation is performed for the functional safety of the vehicle. By performing voltage simulation on the safety-related load as the object, it is possible to determine whether power can be supplied from the battery 50 to the safety-related load during the period (for example, about 1 minute) until the vehicle stops corresponding to the safety-related load when a failure occurs in the vehicle power generation system (DCDC, AC generator) during automatic driving. Voltage simulation is not limited to functional safety, and can be used for other purposes and purposes such as ensuring comfort.

[0098] The results of voltage simulation, for example, Figure 7 When the judgment at time t2 is that discharge is possible (when Vt>VL), the management device 130 determines that discharge is possible in the discharge mode (power can be supplied to the specific load 160A) during the period t2 to t3 until the next judgment.

[0099] However, if the discharge in the execution cycle T of the voltage simulation is taken into consideration, there is a possibility that the discharge based on the discharge pattern P cannot be performed (erroneous determination of whether the discharge is possible).

[0100] Specifically, the storage battery 50 may discharge not only to the specific load 160A that is the target of voltage simulation but also to the general load 160B. Depending on the type of the general load 160B, the storage battery 50 may always discharge.

[0101] When there is discharge to the general load 160B (the same applies to discharge to a load other than the general load 160B such as the specific load 160A), the storage amount of the battery 50 also decreases during the execution cycle T of the voltage simulation.

[0102] For example, at time t2, in a state where discharge based on the discharge pattern P is possible, in a state where the total voltage Vt12 after discharge has a margin with respect to the lower limit voltage VL, after t2, the margin with respect to the lower limit voltage VL is also reduced by performing the discharge in the cycle T. If there is no margin at time ta, when discharge is performed in the discharge pattern P during the period from time ta to the next determination time point t3, the total voltage Vt may be lower than the lower limit voltage VL.

[0103] Fig. 9 1 shows the change of the total voltage Vt when the discharge is started at time tb according to the discharge pattern P. In this example, at a point in time of 10 to 11 seconds after the start of the discharge at time tb, the total voltage Vt falls below the lower limit voltage VL, and the battery 50 reaches a power shortage state.

[0104] In order to solve such a problem, the management device 130 uses an improved discharge pattern P in the voltage simulation.

[0105] like Figure 6B As shown, the improved discharge pattern P adds the second time series data D2 to the first time series data D1. That is, the discharge pattern is set as follows: the discharge time is set to the total time of the first time series data D1 and the second time series data D2, and the second time series data D2 is additionally discharged compared to the case of discharging only the first time series data D1.

[0106] The second time series data D2 is time series data of the discharge current of the storage battery 50 to the general load 160B or the like during the execution cycle T. The second time series data D2 may use a past performance value (fixed value) or the discharge current of the previous cycle T. In addition, it may be switched according to the operating state of the automobile 10. In this embodiment, the discharge current is set to a fixed value of about 50A.

[0107] The improved discharge pattern P is data that is one cycle longer than the unimproved discharge pattern P. The first time series data D1 is 12 seconds, the execution cycle T is 1 second, and the discharge pattern P is data that is 13 seconds.

[0108] In this embodiment, before the first time series data D1 ( Figure 6B The second time series data D2 is added to the left side of the first time series data D1. Figure 6B ) is attached to the right side of the .

[0109] like Fig.10 As shown, the calculation unit 131 receives (A) to (F) as inputs and estimates the time change of the total voltage Vt of the battery pack 60 when the battery pack 60 is discharged in the discharge pattern P (voltage simulation).

[0110] Specifically, as shown in equation (3), by subtracting the voltage change amount ΔV of the total voltage accompanying the discharge in the discharge pattern P from the initial value Vt0 of the total voltage, the temporal change of the total voltage Vt is estimated.

[0111] The voltage change amount ΔV can be calculated based on information such as the SOC of the battery pack 60 , the internal resistance R, the battery temperature TS, and the charge and discharge history Z. ΔV may be calculated using a predetermined calculation formula or a reference table.

[0112] Vt=Vt0-ΔV(SOC, R, I, TS, Z) (3) Equation

[0113] Vt is the total voltage, Vt0 is the initial value of the total voltage, ΔV is the voltage change, R is the internal resistance of the battery pack, I is the discharge current to a specific load, TS is the battery temperature, and Z is the charge and discharge history of the storage battery 50 .

[0114] (A) Improved discharge mode P

[0115] (B) Initial value Vt0 of the total voltage of the battery pack 60

[0116] (C) SOC of the battery pack 60

[0117] (D) Internal resistance R of the battery pack 60

[0118] (E) Battery temperature TS

[0119] (F) Charge and discharge history Z of the battery 50

[0120] Vt0 uses the measured value of the voltage detection unit 110, and TS uses the measured value of the temperature sensor 58. SOC uses the calculated value based on the current product algorithm. I uses the data of the discharge mode. The internal resistance R can use either a fixed value (empirical value) stored in the storage unit 132 or a calculated value obtained based on the measured values ​​I and Vt of the current detection unit 54 and the voltage detection unit 110.

[0121] The reason for including the battery temperature TS in the input value of the voltage simulation is to perform temperature correction on the internal resistance R. When the temperature correction is not performed, the battery temperature TS may be omitted from the input.

[0122] The reason why the charge and discharge history Z (charge and discharge times, etc.) of the battery 50 is included in the input value of the voltage simulation is to consider the increase in internal resistance R due to degradation of the battery 50. When degradation of the battery 50 is not considered, the charge and discharge history Z may be omitted from the input.

[0123] In this embodiment, the specific load 160A is a safety-related load such as an electric brake or an electric steering gear, but it may also be a door lock device or a device for switching the driving mode of the automobile 10. It may also be equipment used for emergency evacuation travel.

[0124] 3. Effect description

[0125] In the voltage simulation, the discharge pattern P to which the second time series data D2 is added is used, thereby preventing a situation in which the storage battery 50 is erroneously determined to be able to discharge even though there is actually no remaining power for discharge in the discharge pattern P due to the discharge of the storage battery 50 in the execution cycle T. Thus, whether or not discharge in the discharge pattern P is possible can be correctly determined.

[0126] <Implementation method 2>

[0127] like Fig.11 As shown, in the second embodiment, the execution cycle T of the voltage simulation is set to two cycles, namely, the first cycle T1 and the second cycle T2, and the execution cycle T can be switched.

[0128] T1 is a short cycle. By selecting T1, the cycle for determining whether discharge in the discharge pattern P is possible becomes shorter, so when the storage battery 50 changes from a dischargeable state to an inability to discharge, this can be detected at an early stage.

[0129] T2 is a long period. By selecting T2, the calculation load of the management device 130 can be reduced and the power consumption can be suppressed.

[0130] The storage unit 132 stores the first discharge mode P1 and the second discharge mode P2. Fig. 12A is the waveform of the first discharge mode P1, Fig. 12B It is the waveform of the second discharge mode P2.

[0131] The first discharge pattern P1 and the second discharge pattern P2 are both composed of the first time series data D1 and the second time series data D2.

[0132] The first discharge mode P1 is for T1 (short cycle), and the second discharge mode P2 is for T2 (long cycle). The two discharge modes P1 and P2 have different second time series data D2 due to different cycles. Specifically, the data length (discharge time) and current value are different.

[0133] Furthermore, the two discharge patterns P1 and P2 are used to determine whether power can be supplied to the same specific load 160A, and the first time series data D1 is common.

[0134] In this embodiment, the execution cycle T and the discharge mode P are switched according to the state of the automobile 10. As shown in FIG. 12 , when the automobile 10 is driving, the first discharge mode P1 is selected and the voltage simulation is performed with the first cycle T1. When the automobile 10 is not driving, the second discharge mode P2 is selected and the voltage simulation is performed with the second cycle T2.

[0135] Fig.13 It is the flow chart of voltage simulation.

[0136] The voltage simulation execution process is composed of seven steps S10 to S70.

[0137] After the management device 130 is activated, the process moves to S10, and the calculation unit 131 determines whether the operation state of the automobile 10 is running. The operation state of the automobile 10 can be determined by communication with the vehicle ECU 140. The operation state of the automobile 10 can also be determined by the current I of the battery 50.

[0138] When the vehicle is traveling, the process proceeds to S20 , and the calculation unit 131 reads the first discharge pattern P1 from the storage unit 132 .

[0139] Thereafter, the calculation unit 131 performs a voltage simulation using the first discharge pattern P1 to estimate a voltage change in the total voltage Vt of the battery pack 60 when the battery pack 60 is discharged in the first discharge pattern P1 ( S40 ).

[0140] After executing the voltage simulation, the calculation unit 131 compares the total voltage Vt of the battery pack 60 with the lower limit voltage VL ( S50 ).

[0141] When Vt≥VL ( S60 : NO), the calculation unit 131 determines that “discharging in the first discharge mode P1 is possible.” Thereafter, the process returns to S10 .

[0142] While the automobile 10 is traveling, the voltage simulation execution process ( S10 , S20 , S40 , S50 , S60 ) is executed in the first cycle T1 .

[0143] If the automobile 10 is shifted to a non-driving state such as a temporary stop or a parked vehicle, a NO determination is made in S10 , and the process shifts to S30 , where the calculation unit 131 reads the second discharge pattern P2 from the storage unit 132 .

[0144] Then, the calculation unit 131 performs a voltage simulation using the read second discharge pattern P2 to estimate a voltage change in the total voltage Vt of the battery pack 60 when the battery pack 60 is discharged in the second discharge pattern P2 ( S40 ).

[0145] The calculation unit 131 compares the total voltage Vt of the battery pack 60 with the lower limit voltage VL, and determines whether or not discharge in the second discharge mode P2 is possible ( S50 , S60 ).

[0146] When the automobile 10 is not traveling, the voltage simulation execution process ( S10 , S30 , S40 , S50 , S60 ) is executed in the second cycle T2 .

[0147] When the result of the voltage simulation is Vt<VL ( S60 : YES), the calculation unit 131 determines that “the battery 50 cannot be discharged in the discharge pattern P”, whether the automobile 10 is running or not running.

[0148] In this case, the process proceeds to S70 , and the management device 130 notifies the vehicle ECU 140 of warning information to prompt the battery 50 to be charged.

[0149] The total voltage Vt of the battery 50 increases by charging, and the battery 50 returns to a state where discharge in the first discharge mode P or the second discharge mode is possible.

[0150] In this embodiment, the voltage simulation is performed in the short cycle T1 while the automobile 10 is traveling. Therefore, when the battery 50 reaches a state where discharge in the first discharge mode P1 is not possible, this can be detected at an early stage.

[0151] On the other hand, when the automobile 10 is not traveling, the voltage simulation is executed with the long period T2, so that the power consumption of the management device 130 can be suppressed, thereby achieving energy saving.

[0152] <Implementation method 3>

[0153] In implementation mode 3, Fig.14 As shown, two discharge patterns Pa and Pb are used in the voltage simulation. For example, the first discharge pattern Pa is for a first specific load (an emergency communication device), and the second discharge pattern Pb is for a second specific load (a hazard lamp).

[0154] The first time series data D1 are different between the discharge patterns Pa and Pb, but the second time series data D2 are common. The reason why the first time series data D1 are different is that the specific loads to which the power is supplied are different.

[0155] The calculation unit 131 performs two-mode voltage simulation in parallel using the two discharge modes Pa and Pb. By performing two-mode voltage simulation in parallel, it is possible to determine whether discharge based on the two discharge modes Pa and Pb is possible.

[0156] According to the above example, it is possible to determine whether power can be supplied to the first specific load (emergency communication device) and whether power can be supplied to the second specific load (hazard light).

[0157] With this configuration, the discharge mode of battery 50 can be selected, and thus the discharge control of battery 50 and the vehicle load control by vehicle ECU 140 can be effective.

[0158] In this embodiment, since two discharge modes Pa and Pb are stored, voltage simulation can be performed when discharging simultaneously in the two discharge modes (when power is supplied to multiple specific loads simultaneously), and it can be determined whether simultaneous discharge based on multiple discharge modes Pa and Pb can be performed (whether power can be supplied to multiple specific loads simultaneously).

[0159] <Other embodiments>

[0160] The present invention is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the present invention.

[0161] (1) The storage battery cell 62 is not limited to a lithium ion secondary battery, but may be other non-aqueous electrolyte secondary batteries. The storage battery cell 62 is not limited to a plurality of cells connected in series and parallel, but may be connected in series or a single cell. A capacitor may be used instead of the storage battery cell 62.

[0162] (2) In the above embodiment, the battery 50 is mounted on the automobile 10, but it can also be mounted on a mobile object other than a vehicle such as a ship or an aircraft. In addition, the battery (power storage device) 50 is not limited to a mobile object, but can also be used for fixed installation purposes such as a power storage device for absorbing fluctuations in a distributed power generation system.

[0163] (3) In the above embodiment, the management device 130 is provided inside the storage battery 50. The storage battery 50 only needs to include at least the current detection unit 54, the voltage detection unit 110 and other measuring devices, and the management device 130 and the current interruption device 53 may be located outside the storage battery 50.

[0164] (4) In the second embodiment, the discharge modes P1 and P2 are provided for each of the execution cycles T1 and T2, but the discharge mode P may be common. For example, the average cycle Tav obtained by averaging T1 and T2 may be used as the cycle, and the time series data of the average current Iav obtained by averaging the discharge currents I1 and I2 in T1 and T2 may be used as the discharge current in the cycle.

[0165] (5) The second time series data D2 of the discharge pattern P may also be different depending on the state of the vehicle 10. For example, when the vehicle is running with a large amount of discharge, the value of the second time series data D2 may be increased ( Fig. 12A The first discharge mode P1 shown in FIG. 1 may also reduce the value of the second time series data D2 when the vehicle is not running and the discharge is small ( Fig. 12B In this way, the error of the discharge current (the error between the actual discharge current and the simulated discharge current) can be reduced.

[0166] (6) The first time series data D1 of the discharge pattern P does not matter what the purpose of the discharge is, as long as it is time series data of the amount of discharge current for a predetermined time. As exemplified in the embodiment, the purpose may be to discharge to the specific load 160A, or to discharge to a load other than the specific load 160A, such as the vehicle ECU 140 or the general load 160B. The purpose may also be to discharge to a plurality of loads.

[0167] Explanation of symbols

[0168] 10 Automobile; 50 Storage battery (power storage device); 60 Battery pack; 130 Management device; 131 Calculation unit; 132 Storage unit; 140 Vehicle ECU; 160 Auxiliary machine; 160A Specific load; 160B General load.

Claims

1. A management device that periodically performs voltage simulation of an electric storage device, comprising: Operation Department; as well as Storage Department, The storage unit stores a discharge pattern composed of time series data of a discharge current. The discharge pattern includes first time series data and second time series data of the discharge current, The first time series data is time series data of the amount of discharge current for a predetermined time period, The second time series data is time series data of a discharge current of the power storage device during a voltage simulation execution cycle. The calculation unit periodically executes a voltage simulation for estimating a voltage change of the power storage device when the power storage device is discharged in the discharge mode, and periodically determines whether the power storage device can be discharged in the discharge mode based on a result of the voltage simulation.

2. The management device according to claim 1, wherein: The execution cycle of the voltage simulation can be switched.

3. The management device according to claim 2, wherein: The power storage device is for a vehicle, The computing unit performs voltage simulation at a first cycle when the vehicle is in a first state. The calculation unit executes the voltage simulation at a second cycle when the vehicle is in the second state.

4. The management device according to claim 3, wherein: The first state is that the vehicle is moving, and the second state is that the vehicle is not moving. The second period is longer than the first period.

5. The management device according to claim 3 or claim 4, wherein: The second time series data differs depending on the state of the vehicle.

6. The management device according to claim 5, wherein: The first state is that the vehicle is moving, and the second state is that the vehicle is not moving. The second time series data when the vehicle is not traveling is smaller than the second time series data when the vehicle is traveling.

7. The management device according to claim 2 or claim 3, wherein: The storage unit stores, as the execution cycle of the voltage simulation, a first discharge pattern having time series data for a first cycle and a second discharge pattern having time series data for a second cycle. The calculation unit selects the first discharge mode to perform voltage simulation when the first cycle is selected. The calculation unit selects the second discharge mode and executes the voltage simulation when the second cycle is selected.

8. The management device according to claim 1 or claim 2, wherein: The calculation unit estimates a voltage change of the power storage device based on the SOC of the power storage device, the internal resistance of the battery cell, the discharge current, the temperature of the battery cell, and the charge and discharge history in the voltage simulation.

9. The management device according to claim 1 or claim 2, wherein: The calculation unit performs a plurality of voltage simulations in parallel using a plurality of discharge patterns having different first time series data.

10. An electric storage device comprising: Battery cells; and The management device as claimed in claim 1 or claim 2.

11. A voltage simulation method, wherein: periodically performing a voltage simulation for estimating a voltage change of the power storage device when the power storage device is discharged in a discharge mode; and periodically determining whether or not the power storage device can be discharged in accordance with the discharge pattern based on a result of the voltage simulation, The discharge pattern includes first time series data and second time series data of the discharge current, The first time series data is time series data of the amount of discharge current for a predetermined time period, The second time-series data is time-series data of a discharge current of the power storage device in a voltage simulation execution cycle.

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