Energy storage cell control device, energy storage apparatus, and control method

Abstract

To secure safety of a vehicle by suppressing power loss for at least a predetermined time after an energy storage cell shifts from a first region to a second region.SOLUTION: In the in-vehicle energy storage cell control device 130, the energy storage cell 62 has the first area and the second area in which the battery performances are lower than those in the first area, and when the energy storage cell 62 shifts from the first area A1 to the second area A2, the energy storage cell 62 outputs a signal for notifying the shift of the area A to the car control unit 140 that controls the car 10.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a technology for ensuring the safety of a vehicle by suppressing loss of power supply. [Background technology]

[0002] For example, a battery installed in an automobile has a current interruption device as one of its protection devices. When an abnormality is detected, the current interruption device opens to interrupt the current, thereby protecting the battery (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-5985 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery performance of the battery cell may have a first region and a second region where the battery performance is lower than that of the first region. If the current interruption device is immediately opened to interrupt the current when the battery performance of the battery cell shifts from the first region to the second region, the vehicle may lose power. One aspect of the present invention was developed based on the above circumstances, and by closing the current interruption device for at least a predetermined time after the storage cell transitions from the first region to the second region, power loss is suppressed and vehicle safety is ensured. [Means for solving the problem]

[0005] The storage cell has a first region in terms of battery performance and a second region in which battery performance is lower than that of the first region. When the storage cell transitions from the first region to the second region, the storage cell control device outputs a signal notifying a vehicle control unit that controls the vehicle of the transition of regions, and after outputting the signal, keeps a current interruption device that interrupts current to the storage cell closed for at least a predetermined time, thereby enabling power supply to the vehicle.

[0006] The present technology can also be applied to a control method for a power storage cell (or a power storage device) and a control program for a power storage cell (or a power storage device). [Effects of the Invention]

[0007] This technology can ensure vehicle safety by suppressing power loss. [Brief explanation of the drawings]

[0008] [Figure 1] Side view of the vehicle [Figure 2] Exploded perspective view of the battery [Figure 3] Plan view of a secondary battery cell [Figure 4] Cross section of line AA in Figure 3 [Figure 5] Block diagram showing the electrical configuration of the battery [Figure 6] Battery SOC-P characteristics [Figure 7] Diagram of closing / opening of current interrupting device after fault occurs [Figure 8] Current interrupter control flow [Figure 9] Data Table [Figure 10] Current interrupter control flow [Figure 11] Current interrupter control flow [Figure 12] Battery TP characteristics [Figure 13] Battery IP characteristics [Figure 14A] A diagram showing the timing of charging prohibition after a failure occurs [Figure 14B] A diagram showing the timing of charging prohibition after a failure occurs DETAILED DESCRIPTION OF THE INVENTION

[0009] An overview of a control device for an in-vehicle storage cell will be described. The storage cell has a first region in terms of battery performance and a second region in which battery performance is lower than that of the first region. When the storage cell transitions from the first region to the second region, the control device outputs a signal notifying a vehicle control unit that controls the vehicle of the transition of the region, and after outputting the signal, keeps a current interruption device that interrupts current to the storage cell closed for at least a predetermined time, thereby enabling power supply to the vehicle.

[0010] In this configuration, when the energy storage cell transitions from the first region to the second region, the control device outputs a signal to the vehicle control unit that controls the vehicle to notify the transition of the region. After outputting the signal, the control device does not switch the current interruption device from closed to open, but keeps it closed for a predetermined time.

[0011] The above configuration makes it possible to maintain the vehicle's power supply for a predetermined time after the signal is output, allowing the driver to take safety measures, such as bringing the vehicle to an emergency stop in a safe place, if the vehicle is moving. This ensures the safety of the vehicle. Even when the vehicle is not moving, by keeping the current interrupter closed, it is possible to ensure power for vehicle control necessary when the driver leaves the vehicle, such as controlling the opening and closing of windows and locking of doors.

[0012] In addition to the first region and the second region, the storage cell may have a third region where battery performance is further reduced compared to the second region, and the control device may open the current interruption device to interrupt the current when the storage cell transitions from the second region to the third region after outputting the signal.

[0013] In this configuration, if the storage cell transitions from the second region to the third region after the signal is output, the current interruption device opens to interrupt the current. By interrupting the current, it is possible to prevent the storage cell from being used in the third region.

[0014] The predetermined time may be changed based on at least one of the voltage, current, and temperature of the storage cell at the stage of transition from the first region to the second region. The progression of deterioration in the battery performance of the storage cell and the time required for transition between regions depend on the voltage, current, and temperature. For example, if the current is small and it is expected that a long time will be required for transition between regions, the predetermined time is extended. In this way, it is possible to set the time according to the state of the storage cell at the time of transition.

[0015] Charging of the power storage cells may be prohibited after the vehicle has stopped or the engine has stopped, which can prevent the power storage cells from transitioning to the third region due to charging after the vehicle has stopped or the engine has stopped.

[0016] Discharge of the power storage cell after the vehicle has stopped may be permitted regardless of whether the predetermined time has elapsed. By permitting discharge after the vehicle has stopped, the SOC of the power storage cell decreases. When the power storage cell is replaced after the vehicle has stopped, it can be removed from the vehicle in a state where the SOC is decreased, thereby ensuring the safety of the work. By permitting discharge after the vehicle has stopped, it is possible to notify the outside that the vehicle is making an emergency stop by, for example, issuing an emergency signal (such as a signal to turn on hazard lights) using the power storage cell as a power source.

[0017] When the vehicle equipped with the storage cell is running, the current interruption device may be kept closed for at least the predetermined time after the storage cell has transitioned from the first region to the second region, and when the vehicle equipped with the storage cell is not running, the current interruption device may be switched from closed to open at the stage when the storage cell has transitioned from the first region to the second region.

[0018] In this configuration, the connection state of the current interruption device is switched depending on whether the vehicle equipped with the energy storage cell is moving or not. This makes it possible to minimize the use of the energy storage cell in the second region while ensuring the safety of the vehicle. In other words, when the vehicle is moving, the current interruption device is closed for a predetermined time after transitioning from the first region to the second region to maintain power supply, thereby ensuring the safety of the vehicle. When the vehicle is not moving, the current interruption device is opened to interrupt the current after transitioning from the first region to the second region, thereby minimizing the use of the energy storage cell in the second region.

[0019] When the storage cell transitions from the first region to the second region while not mounted on the vehicle, the current interruption device may be switched from closed to open at the transition stage. When the storage cell is not mounted on the vehicle, there is little need to maintain power, as is the case when the vehicle is not running. By opening the current interruption device to interrupt the current, it is possible to minimize the use of the non-mounted storage cell in the second region.

[0020] <Embodiment 1> 1. Battery 50 Description

[0021] As shown in FIG. 1, vehicle 10 is equipped with engine 20 and battery 50 used when starting engine 20, etc. Battery 50 is an example of an "electricity storage device." As shown in FIG. 2, battery 50 includes a battery pack 60, a circuit board unit 65, and a housing 71. Vehicle 10 may be equipped with an electricity storage device for driving the vehicle or a fuel cell instead of engine 20 (internal combustion engine).

[0022] The container 71 includes a main body 73 and a lid 74 made of synthetic resin material. The main body 73 is cylindrical with a bottom. The main body 73 includes a bottom portion 75 and four side portions 76. The four side portions 76 form an upper opening 77 at the top end.

[0023] The container 71 houses the battery pack 60 and the circuit board unit 65. The circuit board unit 65 is disposed above the battery pack 60.

[0024] The lid 74 closes the upper opening 77 of the main body 73. An outer peripheral wall 78 is provided around the periphery of the lid 74. The lid 74 has a protruding portion 79 that is generally T-shaped in plan view. The positive electrode external terminal 51 is fixed to one corner of the front of the lid 74, and the negative electrode external terminal 52 is fixed to the other corner.

[0025] 3 and 4, the secondary battery cell 62 is configured by housing an electrode assembly 83 together with a non-aqueous electrolyte in a rectangular parallelepiped case 82. The secondary battery cell 62 is, for example, a lithium-ion secondary battery. The case 82 has a case body 84 and a lid 85 that closes the upper opening.

[0026] 4 is not shown in detail, but is composed of a negative electrode element made of a copper foil substrate coated with an active material, and a positive electrode element made of an aluminum foil substrate coated with an active material, with a separator made of a porous resin film disposed between them. Both are strip-shaped, and the negative electrode element and positive electrode element are wound flat so that they can be housed in a case body 84, with the negative electrode element and positive electrode element offset from each other on opposite sides in the width direction relative to the separator. The electrode body 83 may be of a laminated type instead of a wound type.

[0027] A positive electrode terminal 87 is connected to the positive electrode element via a positive electrode current collector 86, and a negative electrode terminal 89 is connected to the negative electrode element via a negative electrode current collector 88. The positive electrode current collector 86 and the negative electrode current collector 88 each comprise a flat base 90 and a leg 91 extending from the base 90. A through hole is formed in the base 90. The leg 91 is connected to the positive electrode element or the negative electrode element. The positive electrode terminal 87 and the negative electrode terminal 89 each comprise a terminal body 92 and a shaft 93 protruding downward from the center of the lower surface of the terminal body 92. Of these, the terminal body 92 and shaft 93 of the positive electrode terminal 87 are integrally molded from aluminum (a single material). In the negative electrode terminal 89, the terminal body 92 is made of aluminum, and the shaft 93 is made of copper, and these are assembled together. The terminal bodies 92 of the positive electrode terminal 87 and the negative electrode terminal 89 are disposed on both ends of the lid 85 via gaskets 94 made of an insulating material, and are exposed to the outside from the gaskets 94 .

[0028] The lid 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. When the internal pressure P of the case 82 exceeds a limit value P3, the pressure release valve 95 opens to reduce the internal pressure P of the case 82.

[0029] 5 is a block diagram showing the electrical configuration of battery 50. Battery 50 includes battery pack 60, current detection resistor 54 serving as a current measurement unit, current interruption device 53, voltage detection circuit 110, temperature sensor 58, and management device 130.

[0030] Two external terminals 51, 52 of the battery 50 are electrically connected to a vehicle ECU (Electronic Control Unit) 140, an alternator 150 which is a generator that generates electricity using the power of the engine 20, and a vehicle load 160 mounted on the vehicle, respectively. The vehicle ECU 140 is a vehicle control unit that controls the vehicle 10. The vehicle ECU 140 controls the alternator 150 and the vehicle load 160. The vehicle ECU 140 may also control a drive system such as an engine. The number of vehicle ECUs 140 is not limited to one, and multiple vehicle ECUs 140 may be used.

[0031] When the engine 20 is running, if the amount of power generated by the alternator 150 is greater than the power consumption of the vehicle load 160, the battery 50 is charged by the alternator 150. If the amount of power generated by the alternator 150 is less than the power consumption of the vehicle load 160, the battery 50 discharges to make up for the shortfall.

[0032] While the engine 20 is stopped, the alternator 150 stops generating power. The battery 50 is not charged, and only discharges power to the vehicle ECU 140 and the vehicle load 160.

[0033] The battery pack 60 is composed of multiple secondary battery cells 62. There are 12 secondary battery cells 62, with three connected in parallel and four connected in series. In FIG. 5, three secondary battery cells 62 connected in parallel are represented by one battery symbol. The secondary battery cells 12 are an example of a "storage cell." The battery 50 is rated at 12V.

[0034] The battery pack 60, the current interruption device 53, and the current detection resistor 54 are connected in series via power lines 55P and 55N. The power lines 55P and 55N can be bus bars BSB, which are plate-shaped conductors made of a metal material such as copper. The power lines 55P and 55N are an example of a current path.

[0035] 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.

[0036] 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 an FET, or a relay having mechanical contacts. The current interruption device 53 is normally closed and is controlled to be closed under normal circumstances.

[0037] The current detection resistor is provided on the negative power line 55N. The current I of the battery pack 60 can be measured based on the voltage Vr across the current detection resistor .

[0038] The voltage detection circuit 110 can detect the voltage V of the secondary battery cells 62 and the total voltage Vab of the battery pack 60. The temperature sensor 58 is attached to the battery pack 60 and detects the temperature T of the battery pack 60.

[0039] The management device 130 is mounted on the circuit board 100, and includes a CPU 131, a memory 132, and a communication unit 133. The management device 130 is an example of a "control device."

[0040] 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 signals related to the operating state of the vehicle 10 (driving, stopped, parked, etc.) from the vehicle ECU 140 via communication.

[0041] The management device 130 monitors the state of the battery 50 based on the outputs of the voltage detection circuit 110, the current detection resistor 54, and the temperature sensor 58. That is, the temperature T, the current I, and the total voltage Vab of the battery pack 60 are monitored.

[0042] The management device 130 performs a process of estimating the SOC [%] of the battery pack 60 based on the current I of the battery pack 60 .

[0043] SOC (state of charge) is the ratio of remaining capacity to full charge capacity, and is expressed by the following formula (1).

[0044] SOC=(Cr / Co)×100 (1) Co is the full charge capacity of the secondary battery, and Cr is the remaining capacity of the secondary battery.

[0045] As shown in the following equation (2), the SOC can be estimated based on the integral of the current I over time. The sign of the current is positive during charging and negative during discharging.

[0046] SOC=SOCo+100×(∫Idt / Co)···(2) SOCo is the initial value of SOC, and I is the current.

[0047] The memory 132 stores a program for estimating the SOC and an execution program for the control flow shown in FIG. 8. Data required for executing these programs is also stored. The programs can be stored on a recording medium such as a CD-ROM and transferred. The programs can also be distributed via telecommunications lines.

[0048] 2. Characteristics of the secondary battery cell 62 6 is a graph showing the SOC-P characteristics of a secondary battery cell 62, with the horizontal axis representing SOC [%] and the vertical axis representing the internal pressure P [Pa] of the secondary battery cell. The internal pressure P is the pressure inside the case 82 of the secondary battery cell 62. The secondary battery cell 62 has three regions A1 to A3 where the amount of change in the internal pressure P relative to the amount of change in SOC, i.e., the slope of the graph, differs.

[0049] The first region A1 is a region where the SOC is 100% or less, the second region A2 is a region where the SOC is 100% to 108%, and the third region A3 is a region where the SOC is 108% or more.

[0050] The first region A1 is a normal use region of the secondary battery cell 62, where the internal pressure P is equal to or lower than the upper use limit value P1. The upper use limit value P1 is the upper limit of the internal pressure P at which the secondary battery cell 62 can be used safely.

[0051] The second region A2 is a region where the internal pressure P is greater than the upper usage limit P1 and is higher than the internal pressure P in the first region A1. Although use in the second region A2 is unlikely to cause an unsafe event in the secondary battery cells 62, it is not a region in which use is recommended.

[0052] The third area A3 is an unsafe area where the internal pressure P is higher than that of the second area A2 and where it is difficult to ensure the safety of the secondary battery cells 62. In the third area A3, there is a possibility that the secondary battery cells 62 may experience an unsafe event during use.

[0053] The limit value P3 at which the pressure release valve 95 operates is included in the third region A3, and after the secondary battery cell 62 moves into the third region A3, when the internal pressure P rises to the limit value P3, the pressure release valve 95 opens to reduce the internal pressure P.

[0054] The change in internal pressure P relative to the change in SOC is greatest in the third region A3, followed by the second region A2 and the first region A1. In the first region A1, the change in internal pressure P is small and is equal to or less than a predetermined value.

[0055] The magnitude relationship of the internal pressure change: A3>A2>A1

[0056] The reason why the amount of change in internal pressure differs is thought to be that the higher the SOC, the higher the voltage V of the secondary battery cell 62, which makes it easier for the electrolyte inside the cell to decompose and vaporize.

[0057] There is a correlation between the "internal pressure P" of the secondary battery cell 62 and "battery performance," and the higher the internal pressure P, the lower the battery performance. Indicators of "battery performance" include the internal resistance [Ω] of the secondary battery cell 62, the capacity retention rate [%], and the battery output [W]. Battery performance may be determined by comprehensively assessing these indicators, or by using any one of them as a representative value.

[0058] When used under the same conditions (for example, the same C rate), the second region A2 is a region where battery performance deteriorates because the internal pressure P is higher than in the first region A1. The second region A2 is a region where the change in internal pressure P is larger than in the first region A1, so the deterioration of battery performance accelerates (a region where the deterioration of battery performance with respect to a change in SOC is larger). The third region A3 is a region where the internal pressure P is higher than in the second region A2, so the deterioration of battery performance deteriorates further. The third region A3 is a region where the change in internal pressure P is larger than in the second region A2, so the deterioration of battery performance deteriorates further (a region where the deterioration of battery performance with respect to a change in SOC is even larger).

[0059] Since the decomposition of the electrolyte is irreversible, once the second region A2 or the third region A3 has been experienced, the internal pressure P will not return to its original state even if the battery returns to the first region A1, and the battery performance will not recover.

[0060] 2. Ensuring the safety of vehicles 10 and preventing unsafe events The vehicle ECU 140 controls charging of the alternator 150 so as not to exceed SOC 100%, which is the upper limit of the first region A1. However, if charging control becomes impossible due to a malfunction of the alternator 150, charging may continue even if SOC exceeds 100%, and the battery pack 60 may shift from the first region A1, which is the normal use region, to the second region A2, where the internal pressure P is high and battery performance deteriorates.

[0061] The management device 130 monitors the SOC and voltage, and when the battery pack 60 transitions to the second region A2 (time t1 shown in FIG. 7), it outputs a signal to the vehicle ECU 140 notifying the transition to region A. When the vehicle ECU 140 receives the signal, it requests or urges the driver to make an emergency stop of the vehicle 10, for example, by turning on a warning lamp.

[0062] After outputting the signal to vehicle ECU 140, management device 130 does not switch current interrupt device 53 from closed to open, but keeps it closed for a predetermined time Tw (t1 to t2 shown in FIG. 7).

[0063] By keeping the circuit closed for a predetermined time Tw after the signal is output, power can be supplied from the battery 50 to the vehicle 10 even if the power supply from the faulty alternator 150 to the vehicle 10 is stopped.

[0064] Therefore, it is possible to maintain the power supply to the vehicle 10 for the predetermined time Tw, and if the vehicle 10 is traveling, the driver can make an emergency stop of the vehicle 10 in a safe place.

[0065] After a predetermined time Tw has elapsed (after t2 in FIG. 7), the management device 130 may switch the current interruption device 53 from closed to open to prohibit reuse of the battery 50. The reason for prohibiting reuse is that during the predetermined time Tw after the signal output, the battery is used in the second region A2, and the internal pressure P of the secondary battery cells 62 is greater than the upper usage limit P1 at which the battery pack 60 can be used safely.

[0066] The amount of change in the internal pressure P of the secondary battery cell 62 that has transitioned to the second region A2 depends on the temperature T of the battery pack 60. In other words, the higher the temperature T of the battery 50, the greater the change in the internal pressure P. The SOC change depends on the total voltage Vab and the charging current I, and the higher the total voltage Vab and the charging current I, the more likely it is that the transition from the second region A2 to the third region A3 will occur. The reason why the transition to region A is more likely the higher the total voltage Vab is is that the higher the total voltage, the higher the charging voltage, and therefore the larger the charging current I.

[0067] Therefore, the predetermined time Tw may be changed depending on the total voltage Vab, charging current I, and temperature T of the battery pack 60 at the time of signal output. In other words, the lower the total voltage Vab of the battery 50 at the time of signal output, the longer the predetermined time Tw may be. The smaller the charging current I, the longer the predetermined time Tw may be. The lower the temperature T, the longer the predetermined time Tw may be. It is preferable that the predetermined time Tw be approximately 2 to 3 minutes.

[0068] FIG. 8 shows a control flow of the current interruption device 53. The control flow is made up of nine steps S10 to S90, and is executed when the battery 50 receives from the vehicle ECU 140 a running start signal that notifies the vehicle 10 that it has started running.

[0069] When the management device 130 receives the running start signal, it detects whether charging is being performed based on the measurement value of the current detection resistor 54 and its polarity (S10).

[0070] When charging is detected, the management device 130 detects the ranges A1 to A3 of the battery 50 based on the current value of the SOC (S20). Since the SOC is usually 100% or less, the battery 50 is included in the first range A1.

[0071] The management device 130 then determines whether the battery pack 60 has transitioned from the first region A1 to the second region A2 (S30). If the battery pack 60 has not transitioned, the process returns to S20.

[0072] If the vehicle ECU 140 becomes unable to control charging due to a malfunction of the alternator or the like, the battery 50 may continue to be charged while the vehicle is running, and the SOC may exceed 100%.

[0073] When the SOC exceeds 100% and the battery pack 60 transitions to the second region A2, the management device 130 calculates the predetermined time Tw based on the total voltage Vab, charging current I, and temperature T of the battery 50 (S40, S50).

[0074] The predetermined time Tw can be calculated using, for example, a two-dimensional data table with two variables I and V. Fig. 9 shows an example of the data table.

[0075] In this embodiment, the data table in Fig. 9 is created for each temperature T. The management device 130 selects a data table corresponding to the battery pack temperature at the time of transition to the second region, and determines the predetermined time Tw from the total voltage Vab and charging current I of the battery pack 60 at the time of transition to the second region.

[0076] The management device 130 then transmits a signal to the vehicle 10 notifying the transition of the battery pack 60 to region A. At this time, the management device 130 may also notify the vehicle 10 of the predetermined time Tw.

[0077] After outputting the signal, the management device 130 keeps the current interruption device 53 closed (S60). Then, the management device 130 counts the time that has passed since the signal was output and determines whether a predetermined time Tw has passed since the signal was output (S70).

[0078] When a predetermined time Tw has elapsed since the signal output, the management device 130 issues a command to the current interruption device 53 to switch the current interruption device 53 from closed to open. By switching the current interruption device 53, the current I of the battery pack 60 can be interrupted.

[0079] The management device 130 determines whether the battery pack 60 has transitioned from the second region A2 to the third region A3 while counting the predetermined time Tw (S90).

[0080] When the secondary battery cell 62 transitions to the third region A3, the current interruption device 53 is switched from closed to open even before the predetermined time Tw has elapsed. By switching the current interruption device 53 to open, it is possible to prevent the battery pack 60 that has transitioned to the third region A3 from reaching an unsafe event. It is also possible to prevent the pressure release valve 95 from opening.

[0081] 3. Explanation of effects In this configuration, when the battery pack 60 transitions from the first region A1 to the second region A2, the management device 130 outputs a signal to the vehicle ECU 140 to notify the transition to region A. After outputting the signal, the management device 130 does not switch the current interruption device 53 from closed to open, but keeps it closed for a predetermined time Tw.

[0082] For a predetermined time Tw after the signal is output, the power supply of the vehicle 10 can be maintained, and if the vehicle is traveling, the driver can take safety measures such as bringing the vehicle 10 to an emergency stop in a safe place, thereby ensuring the safety of the vehicle 10.

[0083] In this configuration, when the battery pack 60 transitions from the second area A2 to the third area A3 after the signal is output, the current interruption device 53 is opened to interrupt the current. By interrupting the current, it is possible to prevent the battery 50 that has transitioned to the third area A3 from reaching an unsafe event.

[0084] In this configuration, the safety of the vehicle 10 is maintained by ensuring the power supply, and the battery 50 can be prevented from reaching an unsafe state.

[0085] <Embodiment 2> The second embodiment discloses the control of the current interruption device 53 after an emergency stop. Fig. 10 shows the control flow of the current interruption device 53 after an emergency stop.

[0086] The control flow of Figure 10 is performed in parallel with the control by the management device 130 to keep the current interruption device 53 closed after a signal notifying the vehicle ECU 140 of the transition to the second region A2 is output from the management device 130 to the vehicle ECU 140.

[0087] The management device 130 detects whether the vehicle 10, which is in emergency operation and has received a signal notifying of a transition to area A, has stopped (S100). The determination of whether the vehicle has stopped may be made by comparing the current I of the battery pack 60 with a threshold value, or by communication with the vehicle ECU 140. In other words, if a signal relating to the operating state of the vehicle 10 (driving, stopped, parked, etc.) can be received from the vehicle ECU 140, the determination may be made based on whether or not the signal has been received.

[0088] When the management device 130 detects that the vehicle 10 has stopped, it determines in which of the first area A1, the second area A2, and the third area A3 the battery pack 60 is located, based on the current value of the SOC (S120).

[0089] When the management device 130 determines that the battery pack 60 is included in the third area A3 (S120: NO), the management device 130 switches the current interruption device 53 from closed to open (S150).

[0090] By switching the current interruption device 53 to open and interrupting the current I, it is possible to prevent the battery pack 60, which has entered the third area A3, from reaching an unsafe event.

[0091] If the battery pack 60 is included in the first area A1 or the second area A2 (S120: YES), the management device 130 determines that the battery pack 60 can be temporarily used except for charging, and keeps the current interruption device 53 closed (S130).

[0092] Thereafter, the management device 130 monitors the output of the current detection resistor 54 and determines whether the battery pack 60 is being "charged" or "discharged" (S140). "Charging" and "discharging" can be determined from the polarity of the current measurement value.

[0093] If the battery pack 60 is being charged (S140: YES), the management device 130 switches the current interruption device 53 to open and interrupts the current, thereby prohibiting charging (S150). By prohibiting charging, it is possible to prevent the battery pack 60 from transitioning to the third region A3.

[0094] If the battery pack 60 is discharging (S140: NO), the management device 130 keeps the current interruption device 53 closed and allows discharging (S130). The closed state is maintained even after a predetermined time Tw has elapsed since the signal output.

[0095] By allowing the battery 50 to discharge, an emergency signal such as hazard lamp illumination can be output using the battery 50 as a power source, thereby making it possible to notify the outside world that the vehicle 10 is making an emergency stop.

[0096] After an emergency stop of the vehicle 10, the SOC of the battery pack 60 decreases due to discharge. Therefore, when the battery 50 that has entered the second range A2 is replaced, it can be removed from the vehicle 10 in a state where the SOC is decreased, thereby ensuring safety.

[0097] <Embodiment 3> In the second embodiment, when the battery pack 60 is charged after an emergency stop, the current interruption device 53 is opened to interrupt the current (S140: YES, S150).

[0098] The current cutoff condition may be any one of (B) to (D). (A) Charging after an emergency stop (B) When the driver's safety is confirmed (C) Use when restarting the vehicle after an emergency stop (D) Discharge with a large current above a specified value (E) Use when the battery temperature is above a specified value (F) Use in over-discharge

[0099] All of (A) to (F) may be set as "shutoff conditions," and the current may be shut off when any of the conditions (A) to (F) is met. Some of (A) to (F) may also be set as shutoff conditions. For example, (A) and (C) may be set as shutoff conditions, and the current may be shut off when either (A) or (C) is met. The shutoff condition is not limited to the combination of (A) and (C), and other combinations may also be set. The number of combinations may be two or more, such as (A) to (C).

[0100] The reason why (B) is included in the shutoff conditions is that if the safety of the driver is confirmed, there is no need to supply power to the vehicle 10 any more. Whether or not safety has been confirmed may be determined based on whether or not the vehicle 10 has shifted to parking after an emergency stop. Whether or not the vehicle is parked may be determined by communication with the vehicle ECU 140. It may also be determined by the current value.

[0101] The reason why (C) is included in the shutoff conditions is to prevent battery 50 that has experienced second range A2 from being used for the same purposes as normal (discharging to a vehicle load or charging by an alternator) when vehicle 10 starts running again. Whether or not to start running again may be determined by communication with vehicle ECU 140.

[0102] The reason why (D) and (E) are included in the cutoff conditions is to prevent the battery 50 that has experienced the second range A2 from generating abnormal heat and leading to an unsafe event.

[0103] The reason why (F) is included in the cutoff conditions is that if over-discharge occurs, power cannot be supplied to the vehicle 10 any more.

[0104] <Embodiment 4> In the first to third embodiments, when the battery pack 60 shifts from the first range A1 to the second range A2, the current interruption device 53 is kept closed for the predetermined time Tw to maintain the power supply of the vehicle 10 that makes an emergency stop.

[0105] The battery pack 60 may transition from the first range A1 to the second range A2 due to the following reasons, in addition to a malfunction of the alternator 150 during running. (a) Charging using an external charger with a different charging voltage (e.g., a 24V charger) (b) Reverse connection of booster cables during jump start (c) External short circuit of the battery (short circuit between external terminals 51 and 52)

[0106] Even if the battery pack 60 transitions from the first region A1 to the second region A2, there is little need to maintain the power supply if the battery 50 is not mounted on the vehicle or the vehicle 10 is not running.

[0107] When the battery pack 60 has shifted from the first region A1 to the second region A2, the management device 130 switches the current interruption device 53 from closed to open in the following cases (S350).

[0108] (1) If the battery is not mounted on the vehicle (S310: NO) (2) When the vehicle 10 is not moving (S320: NO)

[0109] In the cases of (1) and (2), the current interruption device 53 is switched to the open state to interrupt the current, thereby preventing the battery 50 from being used in the second area A2. By preventing the battery 50 from being used in the second area A2, it becomes possible to reuse the battery 50.

[0110] 11 shows the control flow of the current interruption device 53 after the battery 50 has transitioned to the second region A2. Before the transition to the second region A2, the current interruption device 53 is closed.

[0111] When the battery 50 moves from the first range A1 to the second range A2, the management device 130 determines whether the battery 50 is "not mounted on a vehicle" (S310).

[0112] The "non-vehicle" state can be determined based on whether or not a communication line is connected, or based on the current value. In other words, if the communication line is not connected or if the current value is nearly zero for a long period of time, the battery 50 can be determined to be "non-vehicle."

[0113] When the management device 130 determines that the battery 50 is "not mounted on the vehicle" (S310: NO), the management device 130 immediately switches the current interruption device 53 to open (S350).

[0114] When the management device 130 determines that the battery 50 is "mounted" (S310: YES), the management device 130 determines whether the vehicle 10 is "driving" (S320).

[0115] Whether the vehicle 10 is running or not can be determined by communication with the vehicle ECU 140. That is, if communication with the vehicle ECU 140 is frequent, it is determined that the vehicle is running, and if there is no communication for a predetermined period of time, it is determined that the vehicle is not running. If a signal relating to the operating state of the vehicle 10 (running, stopped, parked, etc.) can be received from the vehicle ECU 140, it may be determined based on whether or not the signal is received.

[0116] When the management device 130 determines that the vehicle is not traveling (S320: NO), the management device 130 immediately switches the current interruption device 53 to open (S350).

[0117] When management device 130 determines that the vehicle is "driving" (S320: YES), it outputs a signal to vehicle ECU 140 notifying the transition to region A. Management device 130 keeps current interruption device 53 closed (S330).

[0118] The management device 130 counts the elapsed time after outputting the signal to the vehicle ECU 140. Then, when a predetermined time Tw has elapsed after outputting the signal, the management device 130 switches the current interruption device 53 from closed to open.

[0119] In this configuration, when the region A of the battery pack 60 transitions from the first region A1 to the second region A2, the connection state of the current interruption device 53 is switched depending on whether the vehicle 10 equipped with the battery 50 is moving or not.

[0120] Therefore, it is possible to minimize the use of the battery pack 60 in the second region A2 where the internal pressure is high while ensuring the safety of the vehicle. In other words, when the vehicle 10 is running, after the transition from the first region A1 to the second region A2, the current interruption device 53 is closed for the predetermined time Tw to maintain the power supply, thereby ensuring the safety of the vehicle. When the vehicle 10 is not running, after the transition from the first region A1 to the second region A2, the current interruption device 53 is immediately opened to interrupt the current, thereby minimizing the use of the battery pack 60 in the second region A2.

[0121] When the vehicle 10 is not traveling, preventing the battery pack 60 from being used in the second area A2 can suppress deterioration of the battery 50, enabling reuse of the battery 50. The same applies when the battery 50 is "not mounted on the vehicle."

[0122] <Embodiment 5> In the first embodiment, the battery 50 is divided into three regions A1 to A3 based on the relationship between the SOC and the internal pressure P of the battery pack 60. In the fifth embodiment, the battery 50 is divided into three regions A1 to A3 based on the relationship between the temperature T and the internal pressure P of the battery pack 60.

[0123] FIG. 12 is a graph showing the TP characteristics of the secondary battery cell 62, with the horizontal axis representing the temperature T of the secondary battery cell 62 and the vertical axis representing the internal pressure P of the secondary battery cell 62.

[0124] The secondary battery cell 62 has three regions A1 to A3 in which the amount of change in internal pressure P relative to the amount of change in temperature T, ie, the slope of the graph, differs.

[0125] The first region A1 is a region where the temperature T of the battery pack 60 is T1 [°C] or less, the second region A2 is a region where the temperature T of the battery pack 60 is T1 [°C] to T2 [°C], and the third region A3 is a region where the temperature T of the battery pack 60 is T2 [°C] or more.

[0126] The reason why the amount of change in the internal pressure P differs is thought to be that the higher the temperature T, the more likely a chemical reaction occurs inside the battery, and the more likely the electrolyte is to decompose and vaporize.

[0127] The management device 130 monitors the temperature T of the battery pack 60 based on the output of the temperature sensor 58, and keeps the current interruption device 53 closed when the temperature T is within the first range A1, which is the normal use range.

[0128] When the temperature T of the battery pack 60 transitions to the second region A2 where the internal pressure is high, the management device 130 outputs a signal to the vehicle ECU 140 to notify the transition to region A. After outputting the signal, the management device 130 keeps the current interruption device 53 closed for a predetermined time Tw.

[0129] By keeping the current interruption device 53 closed for the predetermined time Tw, it is possible to maintain power supply until an emergency stop is made to the vehicle 10. The predetermined time Tw may be changed depending on the total voltage Vab and current I of the battery pack 60 at the stage (time point) when the temperature T of the battery pack 60 has transitioned from the first region A1 to the second region A2.

[0130] After outputting the signal to the vehicle 10, the management device 130 monitors the temperature T of the battery pack 60. When the temperature T of the battery pack 60 shifts to the third area A3, which is an unsafe area, the management device 130 sends a command to the current interruption device 53 to switch the current interruption device 53 from closed to open.

[0131] By opening the current interruption device 53 and interrupting the current, it is possible to prevent the battery 50, which has entered the third area A3, from reaching an unsafe event.

[0132] In this configuration, similarly to the first to fourth embodiments, the safety of the vehicle 10 is maintained by ensuring power supply during an emergency stop, and the battery 50 can be prevented from reaching an unsafe state.

[0133] <Embodiment 6> In the fifth embodiment, the battery 50 is divided into three regions A1 to A3 based on the relationship between the temperature T and the internal pressure P of the battery pack 60. The temperature T of the battery pack 60 is correlated with the current I, and the larger the current I, the more likely the temperature of the battery pack 60 will rise.

[0134] In the sixth embodiment, the battery 50 is divided into three regions A1 to A3 based on the relationship between the current I and the internal pressure P of the battery pack 60.

[0135] 13 is a graph showing the IP characteristics of the secondary battery cell 62, with the horizontal axis representing the current I of the secondary battery cell 62 and the vertical axis representing the internal pressure P of the secondary battery cell 62. The current I may be a charging current or a discharging current.

[0136] The first region A1 is a region where the current I of the battery pack 60 is I1 [A] or less, the second region A2 is a region where the current I of the battery pack 60 is I1 [A] to I2 [A], and the third region A3 is a region where the current I of the battery pack 60 is I2 [A] or more.

[0137] The management device 130 monitors the current I of the battery pack 60 based on the output of the current detection resistor 54. When the current I is within the first area A1, which is the normal usage area, the management device 130 keeps the current interruption device 53 closed.

[0138] When the current I of the battery pack 60 shifts to the second region A2 where the internal pressure is high, the management device 130 outputs a signal to the vehicle ECU 140 to notify the shift to region A. After outputting the signal, the management device 130 keeps the current interruption device 53 closed for a predetermined time Tw.

[0139] By keeping the current interruption device 53 closed for the predetermined time Tw, it is possible to maintain power supply until the vehicle 10 makes an emergency stop. The predetermined time Tw may be changed depending on the total voltage Vab and temperature T of the battery pack 60 at the stage (time point) when the current I of the battery pack 60 transitions from the first region A1 to the second region A2.

[0140] After outputting the signal to the vehicle 10, the management device 130 monitors the current I of the battery pack 60. When the current I of the battery pack 60 shifts to the third area A3, which is an unsafe area, the management device 130 sends a command to the current interruption device 53 to switch the current interruption device 53 from closed to open.

[0141] By opening the current interruption device 53 and interrupting the current I, it is possible to prevent the battery 50, which has transitioned to the third area A3, from reaching an unsafe event. The current interruption is performed immediately when the battery pack 60 has transitioned to the third area A3, regardless of whether the predetermined time Tw has elapsed or not.

[0142] In this configuration, similarly to the first to fifth embodiments, the safety of the vehicle 10 is maintained by ensuring power supply during an emergency stop, and the battery 50 can be prevented from reaching an unsafe state.

[0143] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0144] (1) The secondary battery cells 62 are not limited to lithium-ion secondary batteries, and may be other non-aqueous electrolyte secondary batteries. The secondary battery cells 62 are not limited to being connected in series / parallel, but may be connected in series or may be single cells. A capacitor may be used instead of the secondary battery cells 62. Any type of storage cell may be used as long as it has characteristics of having multiple regions with different internal pressures P (a first region and a second region with a higher internal pressure than the first region). The secondary battery cells and capacitors are examples of storage cells.

[0145] (2) In the above embodiment, the transition from the first region A1 to the second region A2 and the transition from the second region A2 to the third region A3 are determined based on the "SOC" of the secondary battery cell 62. The transition of the region may be determined based on another physical quantity as long as the physical quantity is correlated with a decrease in battery performance. For example, the transition may be determined based on the "voltage" of the secondary battery cell 62. In addition to the "voltage," the transition may also be determined based on the "temperature" or "current" of the secondary battery cell.

[0146] (3) In the above embodiment, the secondary battery cell 62 has three regions A1 to A3, namely, the first region A1, the second region A2, and the third region A3, in terms of battery performance. The secondary battery cell 62 only needs to have at least the first region A1 and the second region A2, where the battery performance is lower than that of the first region A1, and the third region A3 may or may not be present.

[0147] The second region A2 may be a region in which battery performance is lower than that of the first region A1, and it does not matter whether the deterioration of battery performance is accelerated or not. In other words, in the case of the SOC-P characteristics shown in Figure 6, the second region A2 may be a region in which the internal pressure P is higher (a region in which battery performance is lower) than that of the first region A1, and the slope of the graph may or may not change. The same applies to the third region A3.

[0148] (4) In the first embodiment, the predetermined time Tw is changed based on the total voltage, current, and temperature of the battery pack 60 at the time of transition to the second region. The predetermined time Tw may be a fixed value. When changing the predetermined time Tw, the predetermined time Tw may be changed based on one of the total voltage, current, and temperature. Alternatively, the predetermined time Tw may be changed based on two of them.

[0149] (5) In the fourth embodiment, when the range A of the battery pack 60 transitions from the first range A1 to the second range A2, the connection state of the current interruption device 53 is switched depending on whether the vehicle 10 equipped with the battery 50 is traveling or not traveling. That is, when the vehicle 10 is traveling, the current interruption device 53 is closed for a predetermined time Tw after the transition from the first range A1 to the second range A2 to maintain power supply. When the vehicle 10 is not traveling, the current interruption device 53 is immediately opened to interrupt the current after the transition from the first range A1 to the second range A2. The current interruption device 53 may be closed for a predetermined time Tw after the transition from the first range A1 to the second range A2 to maintain power supply, not only when the vehicle is traveling but also when the vehicle is not traveling (e.g., when stopped or parked). Maintaining power supply ensures power for vehicle control necessary when the driver leaves the vehicle 10, such as controlling the opening and closing of windows and locking doors. This improves vehicle safety.

[0150] (6) In the above embodiment, the management device 130 is provided inside the battery 50. The battery 50 only needs to include at least instruments such as the current detection resistor 54 and the voltage detection circuit 110, and the management device 130 and the current interruption device 53 may be located outside the battery 50.

[0151] (7) In the above embodiment, the exterior body of the secondary battery cell 62 is a rectangular parallelepiped case (metal can or plastic case) 82, but the exterior body may be a laminate film (pouch cell).

[0152] (8) In the above-described second embodiment, as shown in Fig. 14A, when the battery 50 transitions from the first area A1 to the second area A2, the battery 50 outputs a signal to the vehicle ECU 140 to notify the transition to area A. Then, the current interruption device 53 is kept closed to maintain power until the vehicle 10 is brought to an emergency stop, and after the vehicle 10 makes an emergency stop, charging of the battery 50 is prohibited, thereby preventing the battery 50 from transitioning from area A2 to area A3. As shown in Fig. 14B, the current interruption device 53 may be kept closed to maintain power until the engine is stopped, and charging is prohibited after the engine is stopped, thereby preventing the battery 50 from transitioning from area A2 to area A3. [Explanation of symbols]

[0153] 10 Vehicles 10 50 Battery (energy storage device) 53 Current interrupter 54 Current detection resistor 58 Temperature Sensor 60 battery packs 130 Management device (control device) 140 Vehicle ECU (Vehicle Control Unit) 150 alternator

Claims

1. A control device for an in-vehicle storage cell, The storage cell has a first region and a second region in which the battery performance is lower than that of the first region, When the power storage cell is shifted from the first region to the second region, a signal is output to a vehicle control unit that controls a vehicle to notify the shift of the region; The control device maintains a current interruption device that interrupts the current of the storage cell in a closed state for at least a predetermined time after outputting the signal, thereby enabling power supply to the vehicle.

2. The control device according to claim 1, the storage cell has, in addition to the first region and the second region, a third region in which battery performance is further reduced compared to the second region, a control device that opens the current interruption device to interrupt the current when the storage cell transitions from the second region to the third region after the signal is output.

3. The control device according to claim 1 or 2, a control device that changes the predetermined time based on at least one of a voltage, a current, and a temperature of the power storage cell at a stage when the power storage cell has transitioned from the first region to the second region.

4. The control device according to any one of claims 1 to 3, The control device prohibits charging of the storage cell after the vehicle has stopped or the engine has been stopped.

5. The control device according to any one of claims 1 to 4, The control device permits discharging of the power storage cell after the vehicle has stopped regardless of whether the predetermined time has elapsed.

6. The control device according to any one of claims 1 to 5, When a vehicle equipped with the energy storage cell is traveling, the current interruption device is kept closed for at least the predetermined time after the energy storage cell has transitioned from the first region to the second region; When a vehicle equipped with the power storage cell is not traveling, the control device switches the current interruption device from closed to open when the power storage cell transitions from the first region to the second region.

7. The control device according to any one of claims 1 to 6, When the storage cell transitions from the first region to the second region while not mounted on a vehicle, the control device switches the current interruption device from closed to open at the transition point.

8. A power storage device for a vehicle, A storage cell; a current interruption device that interrupts the current of the storage cell; A power storage device comprising: the control device according to any one of claims 1 to 7.

9. A method for controlling an in-vehicle storage cell, comprising: the storage cell includes a first region and a second region in which an internal pressure of the storage cell is higher than that of the first region, When the power storage cell is shifted from the first region to the second region, a signal is output to a vehicle control unit that controls a vehicle to notify the shift of the region; a control method for maintaining a current interruption device that interrupts the current of the storage cell in a closed state for at least a predetermined time after outputting the signal, thereby enabling power supply to the vehicle.

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