Electric storage device, method for determining connection state

Abstract

To provide a power storage device having a function of determining a connection state of the power storage device with respect to a moving body.SOLUTION: A power storage device for a moving body includes: a power storage cell; an external terminal for connecting the power storage device to the moving body; a current interruption device located on a connection line connecting the power storage cell and the external terminal, and interrupting current in the power storage cell; a first parallel circuit connected in parallel to the current interruption device and the power storage cell; and a control unit. The first parallel circuit includes a resistor, and a switch connected in series to the resistor. The control unit determines an electrical connection state of the power storage device with respect to the moving body, on the basis of the current flowing through the external terminal and the first parallel circuit from the moving body, in a state in which the current interruption device is open and the switch of the first parallel circuit is closed.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a technique for determining the electrical connection state between a battery and a moving body.

Background Art

[0002] For example, a battery mounted on a moving body such as an automobile has a current cutoff device as one of the protection devices. When detecting any abnormality, the battery can be protected by opening the current cutoff device to cut off the current (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the power storage device becomes disconnected from the moving body, the power supply from the power storage device to the moving body stops. Therefore, it is required to determine the connection state of the power storage device to the moving body. One aspect of the present invention provides a technique for determining the connection state of a power storage device to a moving body by focusing on the current flowing from the moving body to the power storage device.

Means for Solving the Problems

[0005] A power storage device for a moving body according to an aspect of the present invention includes a power storage cell, an external terminal for connecting the power storage device to the moving body, a current interruption device in a connection line connecting the power storage cell and the external terminal for interrupting the current of the power storage cell, a first parallel circuit connected in parallel to the current interruption device and the power storage cell, and a control unit. The first parallel circuit includes a resistor and a switch connected in series to the resistor. The control unit determines the electrical connection state of the power storage device to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit in a state where the current interruption device is open and the switch of the first parallel circuit is closed.

[0006] This technology can be applied to a method for determining the electrical connection state of a power storage device to a moving body.

Effect of the Invention

[0007] According to the above aspect, the electrical connection state of the power storage device to the moving body can be determined.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiment for Carrying out the Invention

[0009] The outline of the power storage device for a moving body will be described. The power storage device includes a power storage cell, an external terminal for connecting the power storage device to a moving body, a current cutoff device in a connection line connecting the power storage cell and the external terminal for cutting off the current of the power storage cell, a first parallel circuit connected in parallel to the current cutoff device and the power storage cell, and a control unit. The first parallel circuit includes a resistor and a switch connected in series to the resistor. The control unit determines the electrical connection state of the power storage device with respect to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit in a state where the current cutoff device is open and the switch of the first parallel circuit is closed.

[0010] In this configuration, by closing the switch of the first parallel circuit and opening the current cutoff device, it is possible to form a current path inside the power storage device that bypasses the power storage cell and allows current to flow. Therefore, if the moving body and the power storage device are electrically connected, current flows from the power source mounted on the moving body through the external terminal and the path of the first parallel circuit, and the current returns to the moving body through the external terminal. Therefore, in a state where the current cutoff device is open and the switch of the first parallel circuit is closed, it is possible to determine the electrical connection state of the power storage device with respect to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit. By having a connection state determination function, the power storage device can detect an abnormality in the connection state earlier compared to a case where it does not have such a function, and a highly reliable power storage device can be provided.

[0011] When the switch of the first parallel circuit is open and the current cutoff device is closed, and the power storage cell is in a no-current state (neither charging nor discharging), it is highly likely that the power storage device is not connected to the moving body. However, due to the voltage balance between the terminal voltage of the power storage device and the output voltage of the power source mounted on the moving body, the power storage cell may be in a no-current state.

[0012] When the switch of the first parallel circuit is open and the current cutoff device is closed, and the no-current state of the power storage cell continues for a predetermined period, the control unit may close the switch of the first parallel circuit, switch the current cutoff device to open, and determine the electrical connection state of the power storage device to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit.

[0013] In this configuration, when the power storage cell is in a no-current state, the power storage device is not immediately determined to be disconnected. Instead, the switch of the first parallel circuit is closed and the current cutoff device is switched to open. Due to the voltage balance between the terminal voltage of the power storage cell and the output voltage of the power source mounted on the moving body, when the power storage cell is in a no-current state, closing the switch of the first parallel circuit and switching the current cutoff device to open causes current to flow from the moving body through the external terminal and the first parallel circuit to the power storage device. Since it can be confirmed that the power storage device is connected to the moving body when current flows from the moving body to the power storage device, it is possible to suppress misjudging the connection state of the power storage device as disconnected. By suppressing misjudgment of the connection state of the power storage device, the user does not need to perform a confirmation operation for a connection state that is originally unnecessary, and a highly reliable power storage device can be provided.

[0014] A current sensor may be provided within the range from the external terminal to the parallel connection point of the first parallel circuit among the connection lines connecting the external terminal and the power storage cell.

[0015] In this configuration, the current sensor can be used not only for determining the connection state of the power storage device to the moving body but also for measuring the current of the power storage cell.

[0016] It includes a second parallel circuit connected in parallel with the current cut-off device, and the second parallel circuit may include a diode with the discharge direction of the power storage cell as the forward direction and a switch connected in series with the diode.

[0017] In this configuration, during the open state of the current cut-off device, by closing the switch of the second parallel circuit, power can be supplied from the power storage cell to the moving body through the second parallel circuit. Therefore, it is possible to determine the electrical connection state of the power storage device to the moving body without causing a power fail (power loss) of the moving body.

[0018] The moving body is a vehicle. During the operation of the vehicle, when the no-current state of the power storage cell continues for a predetermined period, the control unit may open the current cut-off device, close the switch of the first parallel circuit, switch to closing the switch of the second parallel circuit, and determine the electrical connection state of the power storage device to the vehicle based on the current flowing from the vehicle through the external terminal and the first parallel circuit.

[0019] During the operation of the vehicle, the power storage cell is frequently charged and discharged. Therefore, when the no-current state (a state where neither charging nor discharging is occurring) continues for a predetermined period, it is highly likely that the power storage device is not connected to the vehicle. In this configuration, it is possible to determine the electrical connection state of the power storage device during the operation of the vehicle without causing a power fail (power loss). In this configuration, since the connection state of the power storage device can be confirmed during the operation of the vehicle, it is effective in improving the safety of the vehicle.

[0020] When the control unit detects a disconnection of the power storage device during the operation of the vehicle, it may notify the vehicle.

[0021] In this configuration, by notifying the vehicle from the power storage device that the power storage device is not connected, it is possible to prompt the driver to take emergency actions such as stopping the vehicle immediately.

[0022] When the control unit detects disconnection of the power storage device during vehicle operation, it may determine that the cable connecting the power storage device and the vehicle has become disconnected or broken.

[0023] With this configuration, it becomes possible to inform the user that the cause of the disconnection of the power storage device is cable disconnection or breakage. If the cause of the disconnection is known, it becomes possible to easily perform the reconnection operation of the power storage device to the vehicle, resulting in high maintainability.

[0024] The control unit may determine the operation or non-operation of the vehicle through communication with the vehicle. With this configuration, since the state of the vehicle is determined using the communication function, it is possible to determine the operation or non-operation of the vehicle without depending on the electrical connection state (connection state via the external terminals) between the vehicle and the power storage device.

[0025] During operation of the drive device of the vehicle, when the non-current state of the power storage cell continues for a predetermined period, the control unit may open the current interruption device, close the switch of the first parallel circuit, switch the switch of the second parallel circuit to closed, and determine the electrical connection state of the power storage device to the vehicle based on the current flowing from the moving body through the external terminal and the first parallel circuit.

[0026] During the operation period of the drive device, compared to the non-operation period, cable disconnection or breakage due to vibration is likely to occur, and there is a high possibility that the power storage device will become disconnected. With this configuration, it is possible to detect an abnormal connection of the power storage device that occurs during operation of the drive device at an early stage.

[0027] The cable for electrically connecting to the vehicle may be screwed to the external terminal. In the case of screwing, there is a possibility that the cable may become loose due to vehicle vibration and become disconnected. By applying this technology, it is possible to detect a poor connection of the power storage device due to cable disconnection, and the safety of the vehicle can be improved.

[0028] <Embodiment 1> 1. Description of Battery 50

[0029] As shown in FIG. 1, an automobile 10 (an example of a moving body) is equipped with an engine 20 and a battery 50 used when starting the engine 20 or the like. The battery 50 is an example of an "electric storage device". As shown in FIG. 2, the battery 50 includes a battery pack 60, a circuit board unit 65, and a housing 71.

[0030] The housing 71 includes a main body 73 made of a synthetic resin material and a lid 74. The main body 73 is a bottomed cylindrical shape. The main body 73 includes a bottom surface portion 75 and four side surface portions 76. An upper opening 77 is formed at the upper end portion by the four side surface portions 76.

[0031] The housing 71 houses the battery pack 60 and the circuit board unit 65. The circuit board unit 65 is disposed above the battery pack 60.

[0032] The lid 74 closes the upper opening 77 of the main body 73. An outer peripheral wall 78 is provided around the lid 74. The lid 74 has a protruding portion 79 that is substantially T-shaped in plan view. Of the front portion of the lid 74, a positive external terminal 51 is fixed to one corner, and a negative external terminal 52 is fixed to the other corner.

[0033] As shown in FIGS. 3 and 4, the secondary battery cell 62 is obtained by housing an electrode body 83 together with a non-aqueous electrolyte in a rectangular parallelepiped case 82. The secondary battery cell 62 is a lithium ion secondary battery cell as an example. The case 82 has a case body 84 and a lid 85 that closes the upper opening thereof.

[0034] Although not shown in detail, the electrode body 83 is formed by disposing a separator made of a porous resin film between a negative electrode element in which an active material is applied to a base material made of copper foil and a positive electrode element in which an active material is applied to a base material made of aluminum foil. All of these are in strip form, and are wound flatly so as to be accommodated in the case body 84 with the negative electrode element and the positive electrode element offset from each other on opposite sides in the width direction with respect to the separator. Instead of the wound type, the electrode body 83 may be of a stacked type.

[0035] 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 pedestal portion 90 and a leg portion 91 extending from the pedestal portion 90. A through hole is formed in the pedestal portion 90. The leg portion 91 is connected to the positive electrode element or the negative electrode element.

[0036] The positive electrode terminal 87 and the negative electrode terminal 89 each comprise a terminal main body portion 92 and a shaft portion 93 protruding downward from the central portion of the lower surface thereof. Among them, the terminal main body portion 92 and the shaft portion 93 of the positive electrode terminal 87 are integrally formed of aluminum (a single material). In the negative electrode terminal 89, the terminal main body portion 92 is made of aluminum and the shaft portion 93 is made of copper, and these are assembled. The terminal main body portions 92 of the positive electrode terminal 87 and the negative electrode terminal 89 are disposed at both ends of the lid 85 via gaskets 94 made of an insulating material, and are exposed outward from the gaskets 94.

[0037] 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 opens when the internal pressure of the case 82 exceeds a limit value, and reduces the internal pressure of the case 82. The secondary battery cell 62 is not limited to a prismatic cell, and may be a cylindrical cell or a pouch cell having a laminated case.

[0038] FIG. 5 is a block diagram showing the electrical configuration of the battery 50. The battery 50 includes a battery pack 60, a current sensor 54, a current cutoff device 53, a first parallel circuit 130, a second parallel circuit 135, and a management device 110. Va, Vc, and Vd in FIG. 5 are the voltages at points A, C, and D on the current path.

[0039] The battery pack 60 is composed of a plurality of secondary battery cells 62. There are 12 secondary battery cells 62, which are connected in 3 parallel and 4 series. FIG. 5 represents 3 secondary battery cells 62 connected in parallel with one battery symbol. The secondary battery cell 12 is an example of a "power storage cell". The battery 50 has a rated voltage of 12V. Instead of connecting 12 secondary battery cells 62 in 3 parallel and 4 series, 4 secondary battery cells 62 may be connected in series to form one battery pack 60.

[0040] The battery pack 60, the current cutoff device 53, and the current sensor 54 are connected in series via the power line 58P and the power line 58N. The power lines 58P and 58N can use a bus bar BSB (see FIG. 2), which is a plate-shaped conductor made of a metal material such as copper. The power lines 58P and 58N are an example of a "connection line".

[0041] The power line 58P connects the positive external terminal 51 and the positive electrode of the battery pack 60. The power line 58N connects the negative external terminal 52 and the negative electrode of the battery pack 60. The external terminals 51 and 52 are terminals for connection to the vehicle 10. A cable 160 is connected to the external terminals 51 and 52 via battery terminals BT1 and BT2. The battery terminals BT1 and BT2 are fixed to the tip of the cable 160 and are attached to the external terminals 51 and 52 by fastening parts 163 such as screws.

[0042] The current cutoff device 53 is provided on the positive power line 58P. The current cutoff device 53 may be a semiconductor switch such as an FET or a relay having a mechanical contact. The current cutoff device 53 is normally closed and is controlled to be closed during normal operation. When there is an abnormality in the battery 50, the current I of the battery pack 60 can be cut off by switching the current cutoff device 53 from closed to open.

[0043] The second parallel circuit 135 is composed of a diode 136 and a switch 137 and is connected in parallel to the current cutoff device 53. The diode 136 has the discharge direction of the battery pack 60 as the forward direction. The switch 137 is connected in series to the diode 136.

[0044] During the open state of the current cutoff device 53, by closing the switch 137, it is possible to discharge to the vehicle 10 via the second parallel circuit 135 while prohibiting the charging of the battery 50.

[0045] The second parallel circuit 135 can also be used for fault diagnosis of the current cutoff device 53. That is, with the switch 137 closed, the current cutoff device 53 is switched from closed to open, and the voltage difference Va - Vc between point A and point C is detected. When the current cutoff device 53 is normally open, the voltage difference Va - Vc is approximately equal to the diode voltage, and when it is stuck in the closed state, the voltage difference Va - Vc is approximately zero. Therefore, the presence or absence of a fault can be diagnosed from the voltage difference Va - Vc.

[0046] The current sensor 54 is provided on the negative power line 58N. The current sensor 54 measures the current I of the battery pack 60.

[0047] The management device 110 is mounted on the circuit board 100 (see Figure 2) and includes a control unit 121, a memory 123, and a first parallel circuit 130.

[0048] The management device 110 is connected to the vehicle ECU 150 via a communication connector 127 and a communication line 128, and communicates with the vehicle ECU 150.

[0049] The management device 110 can receive information on the operation and non-operation of the engine 20, which is a driving device, from the vehicle ECU 150. In addition, it can receive information regarding the state of the automobile 10, such as during driving, stopping, and parking. The communication line 128 is shown only in FIGS. 5 and 12 and is omitted in other figures.

[0050] The control unit 121 monitors the state of the battery 50 based on the outputs of the respective sensors. That is, it monitors the temperature T, current I, and total voltage Vab of the battery pack 60.

[0051] The memory 123 stores a monitoring program for monitoring the state of the battery 50, an execution program for a determination flow (FIG. 11) of the connection state with the automobile 10 via the external terminals 51 and 52, and data necessary for the execution of those programs. The programs can be stored in a recording medium such as a CD-ROM and transferred, etc. The programs can also be distributed using a telecommunication line.

[0052] The first parallel circuit 130 includes a resistor 131 and a switch 133. The switch 133 is connected in series to the resistor 131. One end of the first parallel circuit 130 is connected to point C on the power line 58P (connection point between the external terminal 51 and the current cut-off device 53), and the other end is connected to point B on the power line 58N (connection point between the battery pack 60 and the external terminal 52).

[0053] The first parallel circuit 130 is connected in parallel to the current cut-off device 53 and the battery pack 60. That is, the first parallel circuit 130 is connected in parallel to the series circuit 63 composed of the current cut-off device 53 and the battery pack 60. The first parallel circuit 130 can also be used for discharging the battery pack 60.

[0054] Two external terminals 51 and 52 of the battery 50 are electrically connected to the alternator 140 and the vehicle ECU (Electronic Control Unit) 150 via a cable 160. The vehicle ECU 150 is a vehicle control device.

[0055] The alternator 140 generates electricity by the power of the engine 20. The alternator 140 can charge the 12V battery 50 and can also supply power to vehicle loads such as the vehicle ECU 150. The alternator 140 is an example of an "in-vehicle power supply".

[0056] FIG. 6 shows the charging path and the discharging path of the battery 50. The charging current I1 flows through the alternator 140, the cable 160, the external terminal 51, and the current cut-off device 53 to the battery pack 60. The charging current I1 returns to the alternator 140 through the current sensor 54, the external terminal 52, and the cable 160 (dotted line path).

[0057] The discharging current I2 flows through the battery pack 60, the current cut-off device 53, the external terminal 51, and the cable 160 to the vehicle ECU (load) 150. The discharging current I returns to the battery pack 60 through the cable 160, the external terminal 52, and the current sensor 54 (thick line path).

[0058] The first parallel circuit 130 and the second parallel circuit 135 are circuits for determining the electrical connection state of the battery 50 to the automobile 10. Normally, except when determining the connection state, both the switch 137 of the second parallel circuit 135 and the switch 133 of the first parallel circuit 130 are controlled to be open.

[0059] 2. Determination of the electrical connection state between the battery 50 and the automobile 10 When the battery terminals BT1 and BT2 become loose due to vibrations during driving and the cable 160 comes off from the external terminals 51 and 52, the battery 50 becomes "disconnected" from the automobile 10, and the power supply from the battery 50 to the automobile 10 is interrupted.

[0060] As a method for determining the electrical connection state between the battery 50 and the automobile 10, a method can be considered in which the current I of the battery pack 60 is measured, and when the no-current state of the battery pack 60 (when the current is approximately zero and below a predetermined value) continues for a predetermined period, it is determined as non-connected.

[0061] However, when the terminal voltage Va of the battery pack 60 (the voltage at point A in FIG. 5) is equal to the output voltage Vd of the alternator 140 (the voltage at point D in FIG. 5) (Va = Vd), the battery pack 60 is in a no-current state, that is, as shown in FIG. 5, it is in a state where it neither charges nor discharges.

[0062] Therefore, if the connection state with the automobile 10 is determined only by whether the no-current state of the battery pack 60 continues for a predetermined period, there is a possibility of false detection that the battery 50 and the automobile 10 are non-connected even though the battery 50 is electrically connected to the automobile 10.

[0063] In this embodiment, when the no-current state of the battery pack 60 continues for a predetermined period, the current cutoff device 53, the first parallel circuit 130, and the second parallel circuit 135 are switched as follows, and the electrical connection state between the automobile 10 and the battery 50 is determined by detecting the current flowing from the automobile 10 to the battery 50 (FIGS. 9 and 10).

[0064] (a) Switch the current cutoff device 53 from closed to open. (b) Switch the switch 133 of the first parallel circuit 130 from open to closed. (c) Switch the switch 137 of the second parallel circuit 135 from open to closed.

[0065] FIG. 7 shows the current paths when the current cutoff device 53, the first parallel circuit 130, and the second parallel circuit 135 are switched as in (a) to (c) when the battery 50 and the automobile 10 are normally connected under the condition of Va = Vd.

[0066] When the connection state between the battery 50 and the vehicle 10 is "normal", the output current I3 of the alternator 140 flows from the vehicle 10 to the battery 50. The output current I3 of the alternator 140 flows into the battery through the cable 160, the external terminal 51, and the first parallel circuit 130. The output current I3 returns to the alternator 140 through the current sensor 54, the external terminal 52, and the cable 160 (thick line path). At this time, since Va = Vd, the diode 136 is non-conductive, and the battery pack 60 is in a state where it neither charges nor discharges.

[0067] FIG. 8 shows the current paths when the current cutoff device 53, the first parallel circuit 130, and the second parallel circuit 135 are switched as shown in (a) to (c) when the battery 50 is not connected to the vehicle 10.

[0068] When the battery 50 is "not connected", there is no inflow of the current I3 from the vehicle 10 to the battery 50, and a discharge current I4 flows from the battery pack 60 in the battery 50. The discharge current I4 flows through the second parallel circuit 135 and the first parallel circuit 130 and returns to the battery pack 60 (broken line path).

[0069] Thus, even if the zero-current state of the battery pack 60 continues for a predetermined period, if the battery 50 is connected to the vehicle 10, when the current cutoff device 53, the first parallel circuit 130, and the second parallel circuit 135 are controlled as in (a) to (c), the current I3 flows into the battery through the path passing through the external terminal 51, the first parallel circuit 130, and the external terminal 52 from the alternator 140 which is an in-vehicle power source.

[0070] Therefore, after switching the current cutoff device 53, the first parallel circuit 130, and the second parallel circuit 135 to (a) to (c), if the current I3 is flowing, it can be determined that the connection state between the battery 50 and the vehicle 10 is "normal". If the current I3 is not flowing, it can be determined that the battery 50 and the vehicle 10 are "not connected" and that a disconnection or the like of the cable 160 has occurred.

[0071] The determination of the connection state of the battery 50 is not limited to the presence or absence of the current I3, and may be determined by the level of the current I3. For example, when the connection state is normal and the magnitude of the current I3 flowing from the vehicle 10 to the battery 50 is known, the connection state may be determined by determining the level of the actually measured current I3 based on that value. Any determination method may be used as long as the connection state is determined based on the current I3.

[0072] FIG. 11 is a determination flow for determining the electrical connection state of the battery 50 with respect to the vehicle 10. The determination flow is composed of 14 steps from S10 to S130.

[0073] The control unit 121 usually controls the current cut-off device 53 to be closed, the switch 137 of the second parallel circuit 135 to be open, and the switch 133 of the first parallel circuit 130 to be open. Also at the start point of the determination flow, the states of the current cut-off device 53 and the switches 133 and 137 are as described above.

[0074] After startup, the control unit 121 executes the determination flow in parallel with the monitoring of the battery 50. First, it determines (S10) whether the determination condition for the connection state is satisfied.

[0075] The determination condition for the connection state is a condition for determining whether to execute the determination of the connection state (processing after S20). The determination condition may be, for example, the following three conditions. The predetermined period is about several minutes as an example.

[0076] (1) The vehicle 10 is in an operating state (2) The current cut-off device 53 is closed (3) The current value of the battery pack 60 is below a predetermined value (substantially zero) for a predetermined period

[0077] Whether the vehicle 10 is in an operating state can be confirmed through communication with the vehicle ECU 150. In this embodiment, when the engine, which is a driving device, is operating, the vehicle 10 is determined to be in an operating state. In the case of a hybrid vehicle or an EV, the period during which the engine or the drive motor is operating is determined to be the operating state.

[0078] (3) is satisfied when the assembled battery 60 has been in a state of neither charging nor discharging continuously. Specifically, the following two cases can be exemplified. (3a) Disconnection of the battery 50 (disconnection of the cable 160) (3b) Matching of the terminal voltage Va of the assembled battery 60 and the output voltage Vd of the alternator 140

[0079] During the operation of the vehicle 10, the battery 50 is frequently charged and discharged. Usually, since the charging current and the discharging current are equal to or greater than a predetermined value, the determination condition of S10 is not satisfied.

[0080] When a current equal to or greater than a predetermined value continues to flow for a predetermined period during the operation of the vehicle, a YES determination is made at S15. In this case, the process proceeds to S80, and the control unit 121 determines that the connection state of the battery 50 is "normal", that is, the battery 50 is electrically connected to the vehicle 10.

[0081] When the battery terminals BT1 and BT2 become loose and the cable 160 becomes disconnected during the operation of the vehicle 10, the battery 50 becomes disconnected from the vehicle 10. When it becomes disconnected, the battery 50 enters a no-current state where it neither charges nor discharges. Therefore, when a predetermined period has elapsed since the battery 50 became disconnected, all of the conditions (1) to (3) are satisfied.

[0082] When all of the conditions (1) to (3) are satisfied, the control unit 121 determines that the determination condition for the connection state is satisfied. When the control unit 121 determines that the determination condition for the connection state is satisfied (S10: YES), it gives a command to the second parallel circuit 135 and switches the switch 137 from open to closed (S20).

[0083] Next, the control unit 121 gives a command to the current interrupting device 53 to switch the current interrupting device 53 from closed to open (S30). After that, a command is given to the first parallel circuit 130 to switch the switch 133 of the first parallel circuit 130 from open to closed (S40).

[0084] After switching the current interrupting device 53, switches 133 and 137, the control unit 121 determines whether or not the measured current value measured by the current sensor 54 is in a state of being equal to or less than a predetermined value (substantially zero state) for a certain period (S50). The certain period is, for example, about 30 seconds.

[0085] When the state where the measured current value is substantially zero continues for a certain period (no I3), the control unit 121 determines that the battery 50 is "disconnected" from the vehicle 10 (S60). The determination result is stored in the memory 123. As a factor for disconnection, disconnection of the cable 160 due to loosening of the battery terminal BT is conceivable.

[0086] When the control unit 121 detects "disconnection" of the battery 50 during the operation of the vehicle 10 (S60), it notifies the vehicle ECU 150 of the occurrence of an abnormality (battery disconnection) (S70).

[0087] After notifying the vehicle ECU 150, the control unit 121 checks whether or not the switch 133 of the first parallel circuit 130 is controlled to be open (S100). If the switch 133 of the first parallel circuit 130 is controlled to be open, the process ends there.

[0088] If the switch 133 of the first parallel circuit 130 is controlled to be closed, the control unit 121 switches the current interrupting device 53 from open to closed (S110).

[0089] Thereafter, the switch 133 of the first parallel circuit 130 is switched from closed to open (S120), and further, the switch 137 of the second parallel circuit 135 is switched to closed or open (S130). By switching the current cutoff device 53 and the switches 137 and 133, the current path in the battery returns to the state before the execution of the determination flow.

[0090] When the vehicle ECU 150 receives a notification of an abnormality (battery disconnected) from the battery 50, it turns on the warning lamp to notify the driver of the abnormality. By notifying the abnormality, the driver can be urged to take emergency actions such as moving the automobile 10 to a safe place.

[0091] After the processes of S20 to S40, the case where a current I equal to or greater than a predetermined value is measured as a result of determining the current measurement value (when the determination in S50 is NO) will be described.

[0092] When the control unit 121 measures a current I equal to or greater than a predetermined value (when I3 exists), it determines that the automobile 10 is electrically connected (S80).

[0093] When the control unit 121 makes a connection determination, it resets values such as flags and timers used for executing the determination flow (S90). The information on the determination result stored in the memory 123 may also be reset accordingly.

[0094] Thereafter, the process proceeds to S100. The subsequent processes are the same as the previous description, and by switching the current cutoff device 53 and the switches 133 and 137 in S110 to S130, the states of the current cutoff device 53 and the switches 133 and 137 return to their original states before the execution of the determination flow.

[0095] After startup, the control unit 121 always executes the determination flow of FIG. 11 in parallel with the state monitoring of the battery 50, so that the connection state between the battery 50 and the automobile 10 can always be confirmed. Since the determination flow is always executed during the operation of the automobile 10, if the cable 160 becomes disconnected or the like during the operation of the automobile 10 and the battery 50 becomes disconnected, it can be detected at an early stage.

[0096] 3. Effect Explanation According to the present embodiment, it is possible to accurately determine the connection state with the vehicle 10 via the external terminals 51 and 52. That is, by the coincidence of the terminal voltage Va of the battery pack 60 and the output voltage Vd of the alternator 140, when the battery pack 60 is in a zero-current state, it is possible to suppress misjudging it as "not connected".

[0097] According to the present embodiment, during the determination of the connection state, the switch 137 of the second parallel circuit 135 is closed. By closing the switch 137, power supply to the vehicle 10 through the second parallel circuit 135 becomes possible. Therefore, it is possible to determine the connection state with the vehicle 10 without causing a power fail (power loss) of the vehicle 10.

[0098] <Other Embodiments> The present invention is not limited to the embodiments described by the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

[0099] (1) The secondary battery cell 62 is not limited to a lithium-ion secondary battery, and other non-aqueous electrolyte secondary batteries may be used. A lead-acid battery cell may also be used. The secondary battery cell 62 is not limited to the case where a plurality are connected in series and parallel, and may be connected in series or a single cell. A capacitor may be used instead of the secondary battery cell 62. The secondary battery cell and the capacitor are examples of power storage cells.

[0100] (2) In the above-described embodiment, the battery 50 is for an automobile. The battery 50 is not limited to being for an automobile and may be for a motorcycle. The use of the battery 50 is not limited to vehicles such as automobiles and motorcycles. As long as it is a moving body such as a ship, a railway vehicle, or an aircraft, it can be widely applied even for uses other than vehicle use. Since this technology determines the electrical connection state of the battery 50 to the moving body based on the current flowing from the moving body to the battery 50, the moving body preferably has a configuration having at least a power source other than the battery. The power source may be a generator, a switching power supply, or a battery. The connection method between the moving body and the battery may be a cable or a bus bar. Any connection method may be used as long as electrical connection is possible. When fastening parts such as screws are used to fix the cable or the bus bar, disconnection of the cable or the bus bar may occur, so it is advisable to apply this technology to check the connection state.

[0101] (3) In the above-described embodiment, as an example of an automobile, an engine vehicle was exemplified. The automobile is not limited to an engine vehicle and may be a PHEV vehicle or a BEV vehicle. The in-vehicle power source is not limited to vehicle generators such as the alternator 140. Instead of the alternator 140, a DC-DC converter may be used. The DC-DC converter is a device that steps down the output of the driving battery or the high-voltage battery to supply power to the vehicle load or charge the 12V battery 50.

[0102] (4) In the above embodiment, the current sensor 54 is arranged within the range from the connection point B of the battery pack 60 of the first parallel circuit 130 to the external terminal 52 in the connection line 58N that connects the external terminal 52 and the battery pack 60. The current sensor 54 may be arranged anywhere as long as it is within the range from the external terminals 51 and 52 to the parallel connection point of the first parallel circuit 130 in the connection lines 58P and 58N that connect the external terminals 51 and 52 and the battery pack 60. That is, in the case of the battery 50 shown in FIG. 5, it may be anywhere as long as it is within the range from the external terminal 51 to the parallel connection point C of the current cut-off device 53 of the first parallel circuit 130, or within the range from the parallel connection point B of the battery pack 60 of the first parallel circuit 130 to the external terminal 52. By arranging the current sensor 54 within the above range, not only can the connection state be determined, but the current sensor 54 can also be used for current monitoring of the battery pack 60.

[0103] (5) In the above embodiment, the current cut-off device 53 is arranged at the positive electrode of the battery pack 60, and the current sensor 54 is arranged at the negative electrode. These arrangements may be reversed, that is, the current sensor 54 may be arranged at the positive electrode of the battery pack 60 and the current cut-off device 53 may be arranged at the negative electrode (see FIG. 12).

[0104] (6) In the above embodiment, as a case where the battery 50 becomes disconnected, the disconnection of the cable 160 is described. Due to vibrations during engine operation or driving, the cable 160 may be disconnected, causing the battery 50 to become disconnected. When the control unit 121 detects the disconnection of the battery during the operation of the vehicle 10 (S60), it may determine that the cable 160 connecting the battery 50 and the vehicle 10 is disconnected or broken. With this configuration, it is possible to notify the user that the cause of the disconnection of the battery 50 is the disconnection or breakage of the cable 160. If the cause of the disconnection is known, the reconnection operation of the battery 50 to the vehicle 10 can be easily performed, resulting in high maintainability.

[0105] (7) In the above-described embodiment, when the no-current state (a state where neither charging nor discharging is performed) of the assembled battery 60 continues for a predetermined period, the current cutoff device 53 is switched from closed to open, the switch 133 of the first parallel circuit 130 is switched from open to closed, and the switch 137 of the second parallel circuit 135 is switched from open to closed to determine the connection state of the battery 50 to the automobile 10. Specifically, it was determined based on whether or not a current I3 flows from the automobile 10 through the external terminal 51 and the path of the first parallel circuit 130. The determination of the connection state of the battery 50 to the automobile 10 is not limited to the case where the no-current state of the assembled battery 60 continues for a predetermined period, and may be performed triggered by other conditions. For example, it may be executed when a predetermined time has elapsed since the previous determination, or after a failure diagnosis of the current cutoff device 53 using the second parallel circuit 135. For example, with the switch 137 of the second parallel circuit 135 closed, the current cutoff device 53 is switched from closed to open to diagnose whether or not the current cutoff device 53 is stuck in the closed state. Thereafter, the switch 133 of the first parallel circuit 130 may be switched from open to closed to determine the connection state of the battery 50 to the automobile 10. The determination of the connection state of the battery 50 may be executed regardless of whether the battery 50 is in a no-current state (a state where neither charging nor discharging is performed). The current cutoff device 53 may be closed or open as long as it is controlled to be open at least at the time of determining the connection state. Similarly, as long as the first parallel circuit 130 and the second parallel circuit 135 are controlled to be closed at least at the time of determining the connection state, they may be open or closed otherwise.

[0106] (8) In the above embodiment, the second parallel circuit 135 is provided in parallel with the current cutoff device 53, but the second parallel circuit 135 may be abolished. FIG. 13 is a block diagram of the battery 200 with the second parallel circuit 135 abolished. When the second parallel circuit 135 is abolished, when the no-current state of the battery pack 60 continues for a predetermined period, if the current cutoff device 53 is opened and the switch 133 of the first parallel circuit 130 is switched to closed, only when the battery 50 is connected to the automobile 10 via the external terminals 51 and 52, the current I3 flows from the alternator 140, which is an in-vehicle power supply, through the external terminal 51 and the path of the first parallel circuit 130. When not connected, the current I3 does not flow through the above path.

[0107] Therefore, based on whether there is a current I3 flowing through the path from the alternator 140, which is an in-vehicle power supply, through the external terminal 51 and the first parallel circuit 130 in a state where the current cutoff device 53 is switched from closed to open and the switch 133 of the first parallel circuit 130 is switched from open to closed, the connection state with the automobile 10 via the external terminals 51 and 52 can be determined.

[0108] The presence or absence of the current I3 may be measured by the current sensor 54 used for measuring the current of the battery pack 60, or may be measured by a dedicated current sensor 210. The presence or absence of the current I3 may be detected by detecting a voltage change associated with the current. For example, the voltage change at the intermediate point E of the first parallel circuit 130 may be detected.

[0109] (9) In the above embodiment, the automobile 10 is considered to be in operation during the period when a driving device such as an engine or a drive motor is operating. In addition to the above, during the operation period of the automobile 10, it may include a state where the vehicle power system is activated during plug-in charging, parking (ACC state), and a state where the power of the automobile is utilized as a power storage system during idle stop (V2H). That is, in addition to the case where a driving device of a power system such as an engine or a drive motor is operating, as long as the power system of the automobile 10 is at least activated, it may be included in the operation period of the automobile 10.

Explanation of Reference Numerals

[0110] 10 Automobile 10 (mobile body) 50 Battery (power storage device) 53 Current cutoff device 54 Current sensor 60 Battery pack 110 Management device 121 Control unit 123 Memory 130 First parallel circuit 135 Second parallel circuit 140 Alternator (vehicle-mounted power source) 150 Vehicle ECU (vehicle control device)

Claims

1. A power storage device for a moving body, comprising: a power storage cell; an external terminal for connecting the power storage device to the moving body; a current interruption device in a connection line connecting the power storage cell and the external terminal, for interrupting the current of the power storage cell; a first parallel circuit connected in parallel to the current interruption device and the power storage cell; a control unit, the first parallel circuit includes a resistor and a switch connected in series to the resistor, the control unit determines the electrical connection state of the power storage device with respect to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit in a state where the current interruption device is open and the switch of the first parallel circuit is closed. A power storage device for a moving body.

2. The power storage device for a moving body according to claim 1, when the no-current state of the power storage cell continues for a predetermined period with the switch of the first parallel circuit open and the current interruption device closed, the control unit closes the switch of the first parallel circuit, switches the current interruption device to open, and determines the electrical connection state of the power storage device with respect to the moving body based on the current flowing from the moving body through the external terminal and the first parallel circuit. A power storage device for a moving body.

3. The power storage device for a moving body according to claim 1 or claim 2, comprising a current sensor within a range from the external terminal to the parallel connection point of the first parallel circuit in a connection line connecting the external terminal and the power storage cell. A power storage device for a moving body.

4. The power storage device for a moving body according to any one of claims 1 to 3, comprising a second parallel circuit connected in parallel to the current interruption device, The second parallel circuit includes a diode with the discharging direction of the power storage cell as the forward direction and a switch connected in series with the diode, and is a power storage device for a moving body.

5. The power storage device for a moving body according to claim 4, wherein the moving body is a vehicle, when the no-current state of the power storage cell continues for a predetermined period during the operation of the vehicle, the control unit opens the current cutoff device, closes the switch of the first parallel circuit, switches the switch of the second parallel circuit to closed, and determines the electrical connection state of the power storage device to the vehicle based on the current flowing from the vehicle through the external terminal and the first parallel circuit, and is a power storage device for a vehicle.

6. The power storage device for a vehicle according to claim 5, wherein the control unit notifies the vehicle when detecting non-connection of the power storage device during vehicle operation, and is a power storage device for a vehicle.

7. The power storage device for a vehicle according to claim 5 or claim 6, wherein the control unit determines that there is a disconnection or break in the cable that electrically connects the power storage device and the vehicle when detecting non-connection of the power storage device during vehicle operation, and is a power storage device for a vehicle.

8. The power storage device for a vehicle according to any one of claims 5 to 7, wherein the control unit determines the operation and non-operation of the vehicle through communication with the vehicle, and is a power storage device for a vehicle.

9. The power storage device for a vehicle according to any one of claims 5 to 8, wherein the control unit opens the current cutoff device, closes the switch of the first parallel circuit, switches the switch of the second parallel circuit to closed when the no-current state of the power storage cell continues for a predetermined period during the operation of the drive device of the vehicle, and determines the electrical connection state of the power storage device to the vehicle, and is a power storage device for a vehicle.

10. A power storage device for a vehicle according to any one of claims 5 to 9, wherein a cable for electrically connecting to the vehicle is screwed to the external terminal, the power storage device for a vehicle.

11. A power storage device according to any one of claims 1 to 10, and a power source other than the power storage device, a moving body provided with.

12. A method for determining a connection state of a power storage device for a moving body, wherein the power storage device is a power storage cell, an external terminal for connecting the power storage device to the moving body, a current cutoff device that cuts off the current of the power storage cell in a connection line connecting the power storage cell and the external terminal, and a first parallel circuit connected in parallel to the current cutoff device and the power storage cell, A method for determining a connection state of a power storage device for a moving body, wherein in a state where the current cutoff device is open and the switch of the first parallel circuit is closed, the electrical connection state of the power storage device to the moving body is determined based on the current flowing from the moving body through the external terminal and the first parallel circuit.

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