JP6365725B2 - Power storage device and power path switching device - Google Patents

Description

  The present invention relates to a power storage device including a power storage element.

  A secondary battery such as a lithium ion secondary battery has a battery cell integrated with a protection circuit in order to safely perform a cooperative operation between the battery cell and an external load or a charging device to which the battery cell is connected. It is common to be provided as a battery pack.

  The protection circuit is equipped with a shutoff switch such as a relay that shuts off the power path connecting the battery cell and external load etc. in case of an emergency. The road is shut off, and the battery cell and the external load are protected (see, for example, Patent Document 1, paragraph (0002)).

JP 2010-140785 A

  However, the conventional battery pack has the following problems. That is, when a high-power battery pack is used as an electric vehicle (EV), household or industrial power supply, for example, the possibility of malfunction due to use in an outdoor environment or abnormal operation can be detected stably. There was difficulty. Therefore, further improvement in the reliability of the protection circuit has been demanded.

  The present invention has been made in view of the above-described problems. The power storage device and the power path switching device capable of improving the determination accuracy regarding the opening / closing of the charging / discharging path or the power path and performing protection with high reliability. The purpose is to provide.

In order to achieve the above object, the first aspect of the present invention provides:
A storage element;
A potential difference measuring means for measuring a potential difference between any two points of the charge / discharge path of the power storage element;
A self-holding switch provided between the two points of the charge / discharge path;
Current measuring means for measuring a current in a charge / discharge path of the power storage element;
Opening / closing control means for controlling opening / closing of the self-holding switch based at least on the state of the storage element;
An operation state determination unit for determining an operation state of the self-holding switch based on at least one of the measurement result of the potential difference measurement unit and the measurement result of the current measurement unit and the control state of the switching control unit; ,
It is a power storage device.

The second aspect of the present invention is
The current measuring means includes
Measure current at any one point of the path connected between the storage element and the self-holding switch or on the negative electrode side of the storage element;
1 is a power storage device according to a first aspect of the present invention.

The third aspect of the present invention is
The operating state determining means includes
When the operation state of the self-holding switch is different from the control state of the opening / closing control means,
Causing the open / close control means to drive the self-holding switch;
It is an electrical storage apparatus of the 1st or 2nd side surface of this invention.

The fourth aspect of the present invention is
The operating state determining means includes
In the case where the opening / closing control means performs control to close the self-holding switch,
The magnitude of the difference between the storage element side voltage value between the storage element and the self-holding switch and the charge / discharge side voltage value between the charge source or the discharge destination of the self-holding switch and the storage element is not less than a predetermined value. When it becomes, it is determined that the operation state of the self-holding switch is an open state.
It is a power storage device according to any one of the first to third aspects of the present invention.

The fifth aspect of the present invention provides
The operating state determining means includes
In the case where the opening / closing control means performs control to close the self-holding switch,
The range of fluctuation of the difference between the storage element side voltage value between the storage element and the self-holding switch and the charge / discharge side voltage value between the charge source or the discharge destination of the self-holding switch and the storage element is a predetermined value or more. When it becomes, it is determined that the operation state of the self-holding switch is an open state.
It is a power storage device according to any one of the first to third aspects of the present invention.

The sixth aspect of the present invention provides
The operating state determining means includes
In the case where the opening / closing control means performs control to close the self-holding switch,
The magnitude of the difference between the storage element-side voltage value between the storage element and the self-holding switch and the charge-discharge side voltage value between the self-holding switch and the charge source or discharge destination of the storage element, or the variation of the difference And when the range is equal to or greater than a predetermined value, and
When the current value measured by the current measuring means is substantially 0 [A],
Determining that the operation state of the self-holding switch is an open state;
It is a power storage device according to any one of the first to third aspects of the present invention.

The seventh aspect of the present invention is
The operating state determining means includes
In the case where the opening / closing control means performs control to open the self-holding switch,
The difference between the storage element side voltage value between the storage element and the self-holding switch and the charge / discharge side voltage value between the charge source or the discharge destination of the self-holding switch and the storage element is substantially zero. When [V], it is determined that the operation state of the self-holding switch is a closed state.
It is a power storage device according to any one of the first to third aspects of the present invention.

The eighth aspect of the present invention provides
The operating state determining means includes
In the case where the opening / closing control means performs control to open the self-holding switch,
The difference between the storage element side voltage value between the storage element and the self-holding switch and the charge / discharge side voltage value between the charge source or the discharge destination of the self-holding switch and the storage element is substantially zero. [V], and
When the current value measured by the current measuring means is substantially larger than 0 [A],
It is determined that the operation state of the self-holding switch is a closed state.
It is a power storage device according to any one of the first to third aspects of the present invention.

The ninth aspect of the present invention provides
The self-holding switch opens and closes with a pulse signal.
It is a power storage device according to any one of the first to eighth aspects of the present invention.

The tenth aspect of the present invention provides
The self-holding switch is a latch relay;
It is a power storage device according to any one of the first to ninth aspects of the present invention.

The eleventh aspect of the present invention is
When the operation state of the self-holding switch determined by the operation state determination unit is different from the control state of the open / close control unit, the information processing unit further includes a notification unit that notifies an alarm
It is a power storage device according to any one of the first to tenth aspects of the present invention.

The twelfth aspect of the present invention is
A potential difference measuring means for measuring a potential difference between any two points in the power path;
A self-holding switch provided between the two points of the power path;
Current measuring means for measuring the current of the power path;
An open / close control means for controlling open / close of the self-holding switch based at least on the operating state of the input side of the power path;
An operation state determination unit for determining an operation state of the self-holding switch based on at least one of the measurement result of the potential difference measurement unit and the measurement result of the current measurement unit and the control state of the switching control unit; ,
It is an electric power path switching device.

The thirteenth aspect of the present invention provides
Measure the potential difference between any two points in the power path,
Measuring the current in the power path;
Based on at least the operating state on the input side of the power path, the opening / closing control means controls the opening / closing of a self-holding switch provided between the two points of the power path,
Determining the operating state of the self-holding switch based on at least one of the measurement result of the potential difference and the measurement result of the current and the control state of the switching control means;
This is a power path switching method.

  According to the above aspect of the present invention, in the protection of the power storage device or the like, it is possible to improve the determination accuracy regarding the opening / closing of the charge / discharge path or the power path and to obtain high reliability.

The block diagram which shows the structure of the electrical storage apparatus which concerns on embodiment of this invention The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 1 of this invention. (A) The figure for demonstrating operation | movement of the electrical storage apparatus which concerns on Embodiment 1 of this invention (b) The figure for demonstrating operation | movement of the electrical storage apparatus which concerns on Embodiment 1 of this invention The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 1 of this invention. The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 2 of this invention. The figure for demonstrating operation | movement of the electrical storage apparatus which concerns on Embodiment 2 of this invention The figure which shows the flowchart of the other operation example of the electrical storage apparatus which concerns on embodiment of this invention. (A) The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 3 of this invention (b) The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 3 of this invention The figure which shows the flowchart of operation | movement of the electrical storage apparatus which concerns on Embodiment 4 of this invention. The block diagram which shows the other structural example of the electrical storage apparatus which concerns on embodiment of this invention The block diagram which shows the structure of the electric power path switching device which concerns on embodiment of this invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)

  FIG. 1 is a block diagram showing a configuration of power storage device 1 according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the power storage device 1 according to the first embodiment includes a protection circuit 10 and a lithium ion secondary battery 20 that is a battery cell connected to the protection circuit 10. The lithium ion secondary battery 20 may be a single battery cell or may be configured by connecting a plurality of cells.

  In the protection circuit 10, the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 are formed between the external load or charging device connected to the power storage device 1 and the lithium ion secondary battery 20. Measure the voltage of the main circuit as a discharge path. The current measuring unit 13 measures a current flowing through a path between the latch relay 30 and the external load or the charging device in the main circuit. The open / close control unit 14 acquires information from each of the measurement means in the battery side voltage measurement unit 11, the charge / discharge side voltage measurement unit 12 and other protection circuits 10, and controls the opening / closing of a latch relay 30 described later based on these information.

  When the function of the current measuring unit 13 is executed by a current measuring unit 17 described later, the current measuring unit 13 may be omitted.

  The drive determination unit 15 is realized by a central processing unit (CPU) or the like. The drive determination unit 15 acquires information from each means of the battery side voltage measurement unit 11, the charge / discharge side voltage measurement unit 12, and the drive history storage unit 16, and controls the open / close control unit 14 based on these information. The drive history storage unit 16 is realized by a memory or other storage device, and stores a history of operation commands to the latch relay 30 by the open / close control unit 14. The current measuring unit 17 measures the current flowing through the path between the negative electrode of the lithium ion secondary battery 20 and the negative electrode of the external load or the charging device in the main circuit. Note that the above-described configuration is desirably realized on the same processor C as a monolithic configuration.

  When the function of the current measurement unit 17 is executed by the current measurement unit 13, the current measurement unit 17 may be omitted.

  The latch relay 30 is provided between the connection position of the battery side voltage measurement unit 11 and the connection position of the charge / discharge side voltage measurement unit 12 in the main circuit. The latch relay 30 is a relay that is opened and closed by a control signal from the opening and closing control unit 14 and is kept closed in a normal state. The thermistor 40 is an element that provides the temperature information of the lithium ion secondary battery 20 to the open / close control unit 14 as an electrical resistance value.

  In the above description, the power storage device 1 corresponds to the power storage device of the present invention, the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 correspond to the potential difference measurement unit of the present invention, and the latch relay 30 corresponds to the present invention. The open / close control unit 14 corresponds to a self-holding switch, and corresponds to the open / close control means of the present invention. The lithium ion secondary battery 20 corresponds to a power storage element of the present invention, and the drive operation storage unit 16 and the drive determination unit 15 correspond to an operation state determination unit of the present invention. The current measuring unit 13 or the current measuring unit 17 corresponds to a current measuring unit of the present invention.

  The operation of power storage device 1 according to the first embodiment of the present invention having such a configuration will be described with reference to the flowcharts of FIGS.

(Operation when charging)
As a first operation example, an operation when a charger is connected to the external connection terminal 50 of the protection circuit 10 and the lithium ion secondary battery 20 is charged will be described with reference to a flowchart of FIG.

  When the charger is connected, the current value and the temperature information are given to the switching control unit 14 from the current measurement unit 13 and the thermistor 40 as step 101, respectively. Next, as step 102, the battery-side voltage measurement unit 11 gives the voltage of the main circuit to the switching control unit 14, and then, as step 103, the lithium ion secondary battery 20 is charged. In step 101, a current value may be given from the current measuring unit 17. Also in the following description or each embodiment, although not clearly indicated, acquisition or monitoring of a current value in each step may be performed by the current measurement unit 17.

  During the continuation of the charging operation, the battery side voltage measuring unit 11, the current measuring unit 13, and the thermistor 40 continue to monitor the voltage value, the current value, and the resistance value as the charged state of the lithium ion secondary battery 20 (step 104). If there is an abnormality in the state of charge, that is, a numerical value or a numerical change that is regarded as a failure in the continuation of the charging operation, such as overcharge, temperature rise, voltage drop or fluctuation, the process proceeds to step 105 and the latch relay 30 is operated. Then, control is performed so that the main circuit is opened.

  A control signal based on a 1-bit pulse signal is output from the open / close control unit 14, and the latch relay 30 is opened in response to the control signal from the open / close control unit 14. As a result, the main circuit is opened and the charging operation is stopped. Here, the exchange of signals between the latch relay 30 and the open / close control unit 14 is performed sequentially, and once the control signal is output, the latch relay 30 receives a continuous control signal and an operation current. Keep open.

  Further, after the confirmation of the opening operation of the latch relay 30, after the inspection by the user of the power storage device 1, the lithium ion secondary battery 20 is in a normal state based on the monitoring of the battery side voltage measuring unit 11 by the switching control unit 14. Is determined (step 112), and when it returns to normal, the open / close control unit 14 outputs a control signal for closing the latch relay 30 (step 106), and the main circuit is closed. Return. Note that the main circuit may be returned to the closed state at a timing when it is recognized that the charging state has returned to normal.

  The above operation is the same as the charging operation in a known protection circuit. The drive operation storage unit 16 monitors the control signal output by the opening / closing control unit 14 and stores the latest state of control of the latch relay 30 by the opening / closing control unit 14. Since there are two control states, a closed state and an open state, the state may be held as a 1-bit flag.

  Next, when the state in which the latch relay 30 is in the closed state is stored through step 104 or step 106, the process proceeds to step 107, and the charge / discharge side voltage measurement unit 12 starts the monitoring operation. The drive determination unit 15 acquires the voltage values of the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 that have been operating, and monitors the difference between the two (step 108). It is determined whether or not (step 109). At this time, the voltage value acquired from the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 takes a time width of about several milliseconds to distinguish it from noise, and takes an average value, a median value, etc. It is desirable. The voltage value measured by the battery side voltage measurement unit 11 corresponds to the storage element side voltage value of the present invention, and the voltage value measured by the charge / discharge side voltage measurement unit 12 corresponds to the charge / discharge side voltage value of the present invention. .

  If the result of determination in step 109 is that the difference between the two is less than a predetermined value, the process returns to step 107 and the drive determination unit 15 continues monitoring each measured value. On the other hand, if the difference is equal to or larger than the predetermined value, the process proceeds to step 110, where the drive determination unit 15 determines that the latch relay 30 is malfunctioning and outputs the determination result to the opening / closing control unit 14. Upon receipt of the determination result, the opening / closing control unit 14 outputs a control signal for closing the latch relay 30 (step 111), and drives the latch relay 30.

  Here, a malfunction of the latch relay 30 and a correction operation thereof will be described. Even in a state where the latch relay 30 is controlled to be in the closed state by the series of operations of the above steps 101 to 106, the latch relay 30 may be latched due to external pulse noise that cannot be distinguished from the control signal by the 1-bit pulse signal. The relay 30 may operate independently and become open.

  Therefore, in the present embodiment, the actual open / close state of the main circuit based on the operation of the latch relay 30 is examined by measuring the voltages before and after the latch relay 30 in the main circuit, and this is determined as the control state of the protection circuit 10. By referring to it together, the actual state of the main circuit switching control is judged.

  That is, as shown in FIG. 3A, if the latch relay 30 is normally kept closed, during the charging period from the charging start voltage Va to the full charge voltage Vb (after time t0), The voltage V1 measured by the battery side voltage measuring unit 11 and the voltage V2 measured by the charge / discharge side voltage measuring unit 12 are the same. On the other hand, as shown in FIG. 3 (b), when the latch relay 30 is in the open state (after time t1), the voltage V1 measured by the battery side voltage measuring unit 11 depends on the characteristics of the battery. While the voltage Vc gradually decreases from the voltage value Vc in the charged state, the charging voltage Vd on the charger side is directly reflected on the voltage V2 measured by the charge / discharge side voltage measuring unit 12.

  Accordingly, when the magnitude of the difference between the voltages, that is, the absolute value | V2−V1 | is obtained as a sufficiently large value, the main circuit is in an open state and the drive operation storage unit 16 is referred to. When the state is not controlled by the protection circuit 10, it can be considered that the latch relay 30 is malfunctioning.

  As described above, according to the power storage device 1 of the first embodiment, the potential between two points sandwiching the latch relay 30 in the main circuit is measured, and based on this, the open / close state of the main circuit is determined by the protection circuit. It is possible to check whether the control is correctly reflected. As a result, it is possible to improve the accuracy of determining whether or not a circuit opening / closing malfunction has occurred due to intrusion of external noise or the like. The voltage V1 measured by the battery side voltage measuring unit 11 and the voltage V2 measured by the charge / discharge side voltage measuring unit 12 can be corrected in consideration of the voltage drop when the latch relay 30 is in the closed state. The detection accuracy can be increased, which is more preferable.

  Further, in the present embodiment, the use of the latch relay 30 as an open / close switch of the main circuit provides the following effects.

  In a relay used for a normal protection circuit, it is necessary to always energize a coil which is a built-in mechanism during operation. In particular, at the time of driving, the relay operates by obtaining a current from the storage battery in the power storage device, thereby causing a voltage fluctuation of the lithium ion secondary battery 20. In addition, while the current is flowing through the coil, the impedance of the coil also varies, causing the current flowing through the coil to fluctuate, causing voltage fluctuations in the lithium ion secondary battery 20. These battery voltage fluctuations hinder accurate voltage measurement in the main circuit.

  On the other hand, the latch relay 30 in the present embodiment is a self-holding switch that maintains an open / closed state without the current from each means of the protection circuit 10 flowing continuously. There is little voltage fluctuation (less influence) in the section before and after the latch relay 30 including the secondary battery 20.

  Therefore, the voltage measured by the battery side voltage measuring unit 11 and the charge / discharge side voltage measuring unit 12 is obtained as a stable value, and the open / close control unit 14 and the drive determining unit 15 that monitor these voltages make a highly accurate determination. be able to.

(Operation during discharge)
Next, as a second operation example, an operation when an external load that is operated by the power of the power storage device 1 is connected to the external connection terminal 50 of the protection circuit 10 and the lithium ion secondary battery 20 discharges is illustrated in FIG. This will be described below with reference to the flowchart of FIG.

  When an external load is connected to the power storage device 1 and the operation of the external load is started, the discharge state of the lithium ion secondary battery 20 is determined as steps 201 and 202 from the current measurement unit 13, the thermistor 40, and the battery side voltage measurement unit 11. The current value, temperature information, and voltage value are respectively supplied to the switching control unit 14.

  During the operation of the external load, the switching control unit 14 continues to monitor the voltage value, current value, and resistance value obtained from each of the above parts (step 203). If the discharge state of the lithium ion secondary battery 20 is abnormal, that is, if a numerical value or a numerical change that is regarded as a failure in continuation of the operation of the lithium ion secondary battery 20 is observed, such as a temperature rise, a voltage drop or fluctuation, the power storage device 1 Then, the process proceeds to step 204, where the latch relay 30 is operated, and control is performed so that the main circuit is opened.

  In this case, it is desirable that the new power storage device 1 is connected to an external load to continue the operation, and the previous power storage device 1 is a target for inspection, maintenance, and the like.

  Next, when the numerical abnormality is eliminated by inspection, maintenance, etc., whether or not the lithium ion secondary battery 20 has returned to a normal state based on the monitoring of the battery side voltage measuring unit 11 by the switching control unit 14 or not. If it is judged (step 211) and it returns to normal, the latch relay 30 again shifts to the closed state under the control of the opening / closing control unit 14 (step 205), and the power storage device 1 can again connect and cooperate with the external load. It becomes a state. In either the normal operation state of step 203 or the return state after detection of an abnormality in step 205, information indicating that the latch relay 30 has been controlled to be opened is stored in the drive history storage unit 16 as the latest state. Is done. When it is confirmed that the latch relay 30 is in the closed state, the charge / discharge side voltage measurement unit 12 performs a monitoring operation in step 206.

  The following is the same as the operation at the time of charging, and the drive determination unit 15 acquires the voltage values of the battery side voltage measuring unit 11 and the charge / discharge side voltage measuring unit 12 and calculates the difference between them as in the operation at the time of charging. Monitor (step 207), and if the difference between the two is less than a predetermined value (step 208), the process returns to step 206, and the drive determination unit 15 continues to monitor each measurement value. If the difference is equal to or greater than the predetermined value (step 208), the process proceeds to step 209, where the drive determination unit 15 determines that the latch relay 30 is malfunctioning, and the open / close control unit 14 that has received the determination results A control signal for closing is output (step 208).

  In step 208, the voltage V1 of the battery side voltage measuring unit 11 when the latch relay 30 is in the open state is the same as the voltage when the latch relay 30 is in the closed state, and the charge / discharge side voltage measuring unit 12 is the same. The voltage V2 measured by is substantially floating because the main circuit is open.

  Thus, according to the power storage device 1 of the first embodiment, in any case during charging and discharging, the potential between two points sandwiching the latch relay 30 in the main circuit is measured with high accuracy, and It is possible to confirm whether the open / closed state of the main circuit correctly reflects the control by the protection circuit. As a result, it is possible to improve the accuracy of judgment regarding power path interruption and other power path opening / closing in an emergency and to obtain high reliability.

(Embodiment 2)
The power storage device according to the second embodiment of the present invention is characterized in that the determination method of the drive determination unit 15 during the charging operation is different from that of the first embodiment. Therefore, the configuration is the same as that of the first embodiment, and the operation will be described below with reference to the flowchart of FIG.

  First, the operation from the start of the operation until the drive history determination unit 16 records the state of the latch relay 30 by the opening / closing control unit 14 is the same as that in the first embodiment, and accordingly, steps 101 to 106 in FIG. Is performed.

  Next, the process proceeds to step 301, and the charge / discharge side voltage measurement unit 12 starts the monitoring operation. At this time, the drive determination unit 15 sets the monitoring time of the charge / discharge side voltage measurement unit 12 to a time width in which a significant change can be observed. Next, the drive determination unit 15 starts monitoring the battery side voltage measurement unit 11 so as to synchronize with the monitoring time of the charge / discharge side voltage measurement unit 12 (step 302), takes the difference between the two (step 303), It is determined whether or not this is a voltage fluctuation having a constant change width (step 304).

  When a voltage fluctuation having a certain change width is recognized, the process proceeds to step 305, and the drive determination unit 15 determines that the latch relay 30 is malfunctioning. Upon receiving the determination result, the open / close control unit 14 outputs a control signal for closing the latch relay 30 (step 306).

  The operations in steps 303 to 304 are based on the following principle. That is, as shown in FIG. 6, when the latch relay 30 is in the open state, the voltage measured by the charge / discharge side voltage measurement unit 12 becomes unstable due to being disconnected from the lithium ion secondary battery 20. The voltage V2 measured by the charge / discharge side voltage measurement unit 12 reflects the charge voltage Vd on the charger side, and the ripple component included in the charge voltage Vd can be directly measured. On the other hand, since the voltage V1 on the side of the lithium ion secondary battery 20 that is a DC power supply does not normally include a ripple component, the ripple component is extracted as it is in the difference between the two.

  Therefore, when the magnitude of the difference | V2−V1 | in each voltage difference is greater than a predetermined value, it can be considered that the latch relay 30 is malfunctioning as in the first embodiment.

  When the average value of the voltage V2 is substantially the same as the voltage V1, the magnitude of the voltage difference | V2−V1 | becomes a minute value, and the setting of the predetermined value for determination and comparison is not precise. Required. In the present embodiment, it is possible to make a more precise determination by making a comparison using a ripple component as a measurement object based on qualitative examination rather than a simple comparison of numerical values.

  As described in the first embodiment, the latch relay 30 is a self-holding switch that is maintained in an open / closed state without receiving current from each means of the protection circuit 10, and the latch relay 30 itself is connected to the main circuit. It does not cause voltage fluctuation. This is a configuration suitable for monitoring a ripple component.

  As described above, according to the power storage device of the second embodiment, the fluctuation of the potential between two points sandwiching the latch relay 30 in the main circuit is measured, and based on this, the open / close state of the main circuit is determined as the protection circuit. It can be confirmed whether or not the control by is correctly reflected. As a result, the possibility of malfunction of the protection circuit due to the intrusion of external noise or the like can be reduced and highly accurate determination can be performed.

  In Embodiments 1 and 2 described above, power storage device 1 is described as determining malfunction in the main circuit when latch relay 30 is controlled to be closed by opening / closing control unit 14. Although it did, it is good also as what determines the malfunctioning when the latch relay 30 is controlled so that it may be in an open state.

  An example of the operation in this case is shown in the flowchart of FIG.

  As in the case of each of the above embodiments, charging is started (step 403) if the measurement unit in the protection circuit 10 starts measurement (steps 401 and 402). For example, discharge is performed following the operation of the external load.

  Next, it is determined whether or not there is an abnormality such as overcharge or overdischarge in the charge or discharge state (step 404). If the abnormality is recognized, the latch relay 30 is driven to open (step 405).

  In this state, the charge / discharge side voltage measurement unit 12 starts a monitoring operation (step 406). The drive determination unit 15 acquires the voltage values of the battery-side voltage measurement unit 11 and the charge / discharge-side voltage measurement unit 12 that have been operating in the past, and obtains the difference between them (step 407).

  When the voltages V1 and V2 between two points sandwiching the latch relay 30 in the main circuit are monitored as the same potential, and the magnitude | V2-V1 | of the difference between the two voltages is substantially 0 [V] Then (step 408), the drive determination unit 15 determines that the latch relay 30 is malfunctioning (step 409), and controls the opening / closing control unit 14 so that the latch relay 30 is opened (step 410).

  Note that “substantially 0 [V]” in step 408 means that | V2−V1 | continues for a predetermined time (for example, 0.3 seconds) or longer and is within the error range of the accuracy of the measuring device, or | V2-V1 | is obtained at a predetermined time interval (eg, 0.1 second), and | V2-V1 | is continuously within the error range of the accuracy of the measuring device for a predetermined number of times (eg, 3 times). Means.

  On the other hand, if | V2-V1 | is recognized as a significant value that is not substantially 0 [V], the process returns to step 406, and the drive determination unit 15 continues monitoring each measurement value.

  As described above, even when the protection circuit 10 is operating in the open state, the protection circuit malfunctions by providing the latch relay 30 and measuring the voltage between two points before and after the latch relay 30. Therefore, it is possible to make a highly accurate determination.

(Embodiment 3)
The power storage device according to Embodiment 3 of the present invention is characterized in that the drive determination unit 15 makes a determination that further considers the current value in addition to the voltage value. Therefore, the configuration is the same as in the first embodiment. Hereinafter, control in which the determination based on the current value is further added to the determination based on the voltage value in each of the above embodiments will be described with reference to the flowcharts of FIGS.

  At the time of charging, if the difference between the voltage values of the battery side voltage measuring unit 11 and the charge / discharge side voltage measuring unit 12 is not less than a predetermined value in step 109 of the flowchart of FIG. Transition to step 501 in the flowchart of FIG. Then, the current value monitored by the current measuring unit 17 is acquired, and it is further determined in step 502 whether or not the value is substantially 0 [A]. Here, “substantially 0 [A]” not only means that the current flow is not detected in the measurement, but also a significant numerical value within the error range of the accuracy of the current measuring unit 17. It also includes being detected.

  When it is determined that the current value is substantially 0 [A], the drive determination unit 15 transitions to step 110 in the flowchart of FIG. 2, determines that the latch relay 30 is malfunctioning, and opens / closes control unit. 14 causes the latch relay 30 to be driven. On the other hand, if it is determined that the current value is not substantially 0 [A], the process proceeds to step 107 or 501, and the determination of the operating state of the latch relay 30 based on the voltage value and the current value is continued.

  At the time of discharging, the above steps 501 and 502 are executed between step 208 and step 209 in the flowchart of FIG.

  The drive determination unit 15 can also execute the above-described steps 501 and 502 between step 304 and step 305 in the flowchart of FIG.

  Next, the control to which the determination based on the current value is added in the malfunction determination when the latch relay 30 is controlled to be in the open state will be described with reference to the flowchart of FIG. 7 and FIG. 8B.

  If the difference between the voltage values of the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 is substantially 0 [V] in step 408 of the flowchart of FIG. ) Transitions to step 601 in the flowchart of FIG. Then, the current value monitored by the current measuring unit 17 is acquired, and it is further determined in step 602 whether the value is substantially larger than 0 [A]. Here, “substantially larger than 0 [A]” does not simply mean that the current flow is detected in the measurement, but is significantly different from the accuracy error range of the current measuring unit 17. It means that you can get a good value.

  When it is determined that the current value is substantially larger than 0 [A], the drive determination unit 15 proceeds to step 409 in the flowchart of FIG. 7, determines that the latch relay 30 is malfunctioning, and opens / closes control unit. 14 causes the latch relay 30 to be driven. On the other hand, when it is determined that the current value is not substantially larger than 0 [A], the process proceeds to step 406 or 601 and the determination of the operation state of the latch relay 30 based on the voltage value and the current value is continued.

  As described above, according to the power storage device of the third embodiment, in addition to the voltage values measured by the battery side voltage measuring unit 11 and the charge / discharge side voltage measuring unit 12, the current value measured by the current measuring unit 17 is adjusted. By adding the determination operation based on this, it is possible to further increase the accuracy of determination of malfunction of the latch relay 30.

  In the above description, the determination flow based on the current value shown in FIGS. 8A and 8B is executed after the determination based on the voltage value is performed, but the determination based on the current value is performed. May be performed before the determination based on the voltage value or in parallel with the determination based on the voltage value. In particular, when the determination is performed in parallel, the latch relay 30 can be quickly controlled, and the reliability of the power storage device 1 can be improved.

  In the above description, the determination based on the current value is based on the current value monitored by the current measurement unit 17, but may be based on the current value monitored by the current measurement unit 13. Further, the current measuring units 13 and 17 may be used in combination.

  However, using the current measuring unit 17 alone as described above is preferable for the following reason. That is, since the current measuring unit 13 is connected between the external connection terminal 50 and the latch relay 30, a leakage current from a charger or an external load connected to the external connection terminal 50 flows into the lithium ion secondary. There is a possibility that an accurate current due to the battery 20 cannot be detected. On the other hand, by using the current measuring unit 17 that directly measures the current of the negative electrode of the lithium ion secondary battery 20 as a single unit, a highly accurate and reliable determination can be performed.

  Although the current measurement unit 17 directly measures the current flowing from the negative electrode of the lithium ion secondary battery 20, the current measurement unit 17 may measure the current flowing between the latch relay 30 and the lithium ion secondary battery 20.

(Embodiment 4)
The power storage device according to the fourth embodiment of the present invention is characterized in that the drive determination unit 15 makes a determination based only on a current value when determination using a voltage value is impossible. Therefore, the configuration is the same as in the first embodiment.

  First, the inspection operation of the power storage device 1 will be described with reference to the flowchart of FIG. In a state where a charger or an external load is not connected to the external connection terminal 50, or in a state where the power storage device 1 is not transferring current to the charger or the external load, the drive determination unit 15 performs control input from the outside. By or automatically, the voltage values of the battery side voltage measuring unit 11 and the charge / discharge side voltage measuring unit 12 are acquired (step 701). The acquired voltage value is stored in the drive determination unit 15 itself or compared with a preset value preset in the drive history storage unit 16 (step 702). Here, the preset value is a fixed value set when the power storage device 1 is shipped from the factory, and is measured when the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 operate normally under the conditions of the inspection operation. It is the same value as the value.

  Next, when the obtained measured values of the battery-side voltage measuring unit 11 and the charge / discharge-side voltage measuring unit 12 match the preset values, the process proceeds to step 703 to confirm that each voltage measuring unit is normal. To complete the inspection operation. On the other hand, if any one of the measured values is different from the preset value, the process proceeds to step 704, and the drive determination unit 15 thereafter performs the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12. The judgment based on each measured value is stopped, and the judgment is switched to the judgment based on the current value from the current measuring unit 17.

  Specifically, steps 501 and 502 of FIG. 8A are executed in place of steps 107 to 109 in the flowchart of FIG. 2 of the first embodiment. Similarly, steps 501 and 502 are executed instead of steps 206 to 208 in the flowchart of FIG. 4 of the first embodiment and steps 301 to 304 in the flowchart of FIG. Also, steps 601 and 602 are executed in place of steps 406 to 408 in the flowchart of FIG.

  Thus, according to Embodiment 4 of the present invention, the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 are inspected, and if there is a malfunction, based on the current value measured by the current measurement unit 17. By performing the determination operation, it is possible to improve the reliability of determination of malfunction of the latch relay 30.

  In each of the above-described embodiments, the malfunction determination of the latch relay 30 by the drive determination unit 15 is performed when performing a charging operation or a discharging operation on the power storage device 1. The opening / closing operation of the self-holding switch and the determination of the operation state determination means of the invention may be performed independently of the charging operation or the discharging operation.

  As an example of such an operation, when the power storage device 1 is placed in an external environment unsuitable for the lithium ion secondary battery 20 such as an excessively high or low temperature environment, the thermistor 40 or an external temperature (not shown) is used. A protection operation for opening the latch relay 30 based on the temperature information monitored by the sensor can be mentioned.

  Specifically, in the flowchart of FIG. 7 that determines an erroneous operation of the control that opens the latch relay 30, the latch relay 30 is changed based on the temperature measurement of the thermistor 40 instead of the steps 401 to 404 that perform the charge / discharge operation. Make it work. Note that such a protection operation may be performed regardless of whether a battery charger or an external load is connected, as long as the power storage device 1 is not discharging or charging.

  In each of the above embodiments, in the power storage device 1, the battery side voltage measurement unit 11 and the charge / discharge side voltage measurement unit 12 individually measure the potential between two points, and the drive determination unit 15 takes the difference. In the present invention, the potential difference before and after the latch relay 30 may be directly measured, and the drive determination unit 15 may make the determination based on the magnitude of the potential difference.

  In each of the embodiments described above, the power storage device 1 has been described assuming that the open / close control unit 14 in the protection circuit 10 forcibly drives the latch relay 30 based on the control of the drive determination unit 15. The invention may be realized as a configuration in which only the determination by the drive determination unit 15 is performed without forcibly driving the latch relay 30. In this case, it is more preferable to have a configuration that notifies the result of the drive determination by the drive determination unit 15 to the outside.

  FIG. 10 is a configuration example including a notification unit 60 that receives the determination result of the drive determination unit 15 and notifies that the latch relay 30 is malfunctioning. The notification unit 60 corresponds to the notification unit of the present invention, and is a unit that outputs a signal for allowing a user to recognize that an abnormality has occurred in the power storage device 1 as an alarm, and displays characters, LEDs, etc. It is realized as a means for outputting a light or other video or a means for outputting a buzzer or other sound.

  According to such a configuration, the user can surely know that there is an abnormality in the operation of the power storage device by the highly accurate determination of the present invention. In addition, the alerting | reporting part 60 may be provided separately as an exclusive structure, and may be implement | achieved using indicators, such as LED currently used in the protection circuit. The configuration of the notification unit 60 may be used in combination with the configuration of the first to fourth embodiments.

  In each of the above-described embodiments, the present invention is implemented as the power storage device 1 having the lithium ion secondary battery 20 and having the main circuit as the charge / discharge circuit. It may be realized as a power path switching device that is connected to another constant voltage power source or disposed between power paths that supply power between any two points and functions as a power device or other power path protection device. .

  FIG. 11 is a configuration diagram of the power path switching apparatus 2 having an input terminal 70 connected to the input side of the power path and an output terminal 80 measured on the output side. However, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

  The basic operation of the power path switching device 2 is the same as that of the first embodiment. The current value and the voltage value measured by the current measuring unit 13 and the input side voltage measuring unit 11a are monitored. Operate and cut off the power path. The voltages of the input side voltage measuring unit 11 a corresponding to the battery side voltage measuring unit 11 and the output side voltage measuring unit 12 a corresponding to the charge / discharge side voltage measuring unit 12 provided at both ends of the latch relay 30 are the latch relay 30. Is always monitored when the operation is confirmed to be closed, and when the difference between the two voltages exceeds a predetermined value, the drive determination unit 15 determines an abnormality and controls the open / close control unit 14 to latch. The relay 30 is operated so as to be closed again.

  Also in the above configuration, as in the power storage device of each embodiment, high reliability is obtained by improving the accuracy of determination regarding power path interruption and other power path switching in an emergency. The power path switching device 2 may also have a configuration in which all the above-described configurations of the power storage device 1 of the first to fourth embodiments are arbitrarily applied.

  In the above description, the self-holding switch of the present invention is a latch relay. However, any switch that can continue the opening / closing operation without receiving or transmitting signals from the outside or consuming power is known. However, the configuration of the relay is not limited.

  In the above description, the self-preserving switch according to the present invention operates using a 1-bit pulse signal as a control signal. However, the amount of information is limited to the number of bits as long as it is controlled by the pulse signal. It is not a thing. Further, the signal format is not limited as long as it is controlled by a signal having an information amount of 1 bit.

  In the above description, the storage element of the present invention is a lithium ion secondary battery. However, a nickel-hydrogen battery or other various secondary batteries may be used as long as the battery can be charged and discharged by an electrochemical reaction. . Furthermore, it may be an element that directly stores electricity as electric charges, such as an electric double layer capacitor. In short, the power storage element of the present invention is not limited by a specific method as long as it is an element that can store electricity so as to be charged and discharged.

  In short, various modifications may be made to the above-described embodiments, including those described above, as long as they do not depart from the spirit of the present invention.

  The present invention as described above makes it possible to improve the accuracy with which the charge / discharge path or power path is opened and closed to obtain high reliability, and is useful in the use of secondary batteries and the like.

DESCRIPTION OF SYMBOLS 1 Power storage device 10 Protection circuit 11 Battery side voltage measurement part 12 Charge / discharge side voltage measurement part 13 Current measurement part 14 Opening / closing control part 15 Drive determination part 16 Drive history memory | storage part 17 Current measurement part 20 Lithium ion secondary battery 30 Latch relay 40 Thermistor 50 External connection terminal

Claims (3)

A storage element;
A protection circuit connected to an external connection terminal to which a charger or a generator and an external load are connected;
A power storage device comprising:
The protection circuit is
A potential difference measuring means for measuring a potential difference between any two points of a charge / discharge path between the positive electrode of the power storage element and the external connection terminal;
A self-holding switch provided between the two points of the charge / discharge path;
Current measuring means for measuring a current in a charge / discharge path between the negative electrode of the power storage element and the external connection terminal;
Opening / closing control means for controlling opening / closing of the self-holding switch based at least on the state of the storage element;
Based on at least one of the measurement result of the potential difference measurement means and the measurement result of the current measurement means and the control state of the open / close control means, the open / close state of the self-holding switch correctly reflects the control by the open / close control means. An operation state determination means for determining whether or not
Power storage device. The self-holding switch is a latch relay that is kept in a closed state in a normal state that is not a charging abnormality or a discharging abnormality,
The operating state determining means is configured such that, after the open / close control means outputs a control signal for closing the self-holding switch, the current value measured by the current measuring means at the time of charging or discharging of the storage element is substantially equal to 0 [A], it is determined that the self-holding switch is malfunctioning.
The power storage device according to claim 1. The determination by the operation state determination unit is performed independently of charging or discharging of the power storage element.
The power storage device according to claim 1.

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