JP2015033283A - Balance correction device and electrical storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect a break caused in a balance correction circuit in a simple configuration.SOLUTION: A balance correction circuit 1 including a control circuit 10 for on/of controlling switching elements S1, S2 to connect series-connected electrical storage cells B1, B2 to resistive elements R1, R2 of discharge units U1, U2 until voltages of the electrical storage cells B1, B2 become equal, and voltage sensors VM1, VM2 for measuring first and second voltages that are respective interterminal voltages of the electrical storage cells B1, B2 is configured to acquire the first voltage or the second voltage in one or more states to keep the switching elements S1, S2 on or off, and determine whether or not there is a break in first to third lines that are lines connecting the electrical storage cells B1, B2 and the discharge units U1, U2 on the basis of the acquired voltage.

Description

  The present invention relates to a balance correction device and a power storage device for equalizing voltages between power storage cells or between power storage modules composed of a plurality of power storage cells connected in series in an assembled battery composed of a plurality of power storage cells connected in series.

  In an assembled battery in which a plurality of power storage cells are connected in series, it is necessary to suppress variations in voltage (electromotive force) between the power storage cells in order to prevent a reduction in discharge capacity and a reduction in life. As a mechanism for equalizing the voltage between the storage cells, for example, in Patent Document 1, a plurality of cells connected in series, a cell voltage detecting means for detecting a voltage between the terminals of the cell, and between the terminals of the cell Used for voltage detection, a voltage detection line connecting a cell terminal and a cell voltage detection means terminal, an equalizing discharge circuit for equalizing the voltage between the terminals of a plurality of cells, and one end of which is a resistance to the cell terminal And a capacitor that forms a filter circuit together with a resistor, the other end being held at a predetermined potential and being connected to a terminal of a cell voltage detecting means. Also, in this document, in order to accurately detect the disconnection of the voltage detection line, when the equalizing discharge circuit is not operating, the voltage between the terminals of the cell detected by the cell voltage detection means is out of the predetermined voltage range. In this case, it is described that a disconnection detecting means for determining that the voltage detection line is disconnected is provided.

JP 2012-172992 A

  As a mechanism of disconnection detection, in addition to the method disclosed in Patent Document 1, for example, voltage detection is performed by supplying a current from a current source circuit provided in an integrated circuit for battery management and flowing the current. It is conceivable to detect wire breakage. However, when this method is carried out, it is necessary to prepare a dedicated control command for the control device, and the internal circuit becomes complicated.

  Recently, there is an increasing demand for miniaturization of products provided with power storage devices, and power storage devices mounted on such products have been required to be smaller than ever before. For this reason, a balance correction device applied to a power storage device including a power storage cell or a power storage module is also required to be simple and small.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a balance correction device and a power storage device capable of reliably detecting a disconnection occurring in a circuit with a simple configuration. Yes.

  In order to achieve the above object, one of the present inventions is an assembled battery composed of a plurality of power storage cells connected in series, and between power storage cells or between power storage modules composed of a plurality of power storage cells connected in series. A balance correction device for equalizing voltage, wherein the first and second power storage modules connected in series before and after are connected between positive and negative terminals of the first power storage module. A first discharge unit including a configuration in which one switching element and a first discharge element are connected in series; a second switching element connected to a positive / negative terminal of the second power storage module; A second discharge unit including a configuration in which discharge elements are connected in series; a first voltage that is a voltage between terminals of the first power storage module; and a voltage between terminals of the second power storage module. In order to equalize the second voltage, a control circuit that controls on / off of the first switching element or the second switching element, a first voltage sensor that measures the first voltage, A second voltage sensor that measures the voltage of the second voltage sensor, and wherein the control circuit maintains the first switching element or the second switching element for each of the one or more patterns maintained on or off. 1 is a line that acquires the first voltage or the second voltage and connects the positive electrode of the first power storage module and the first discharge unit based on the acquired first voltage or the second voltage. The first line, the second line that is a line connecting the positive electrode of the second power storage module and the second discharge unit, and the negative electrode of the second power storage module and the second discharge unit are connected. For at least one of the third line is a line determines whether the disconnection has occurred.

  Another aspect of the present invention is the balance correction apparatus including a first capacitive element connected between terminals of the first power storage module, wherein the control circuit is configured to perform the equalization. After stopping on / off control of the first switching element or the second switching element, the first switching element is kept on for a predetermined time to discharge the first capacitor element, and after the predetermined time has elapsed. The first voltage is acquired from the first voltage sensor, and it is determined whether the acquired first voltage is 0 or less than a preset threshold value. It is determined whether or not a disconnection has occurred.

  Another aspect of the present invention is the balance correction apparatus, further including a second capacitor element connected between terminals of the second power storage module, wherein the control circuit is configured to perform the equalization. After stopping the on / off control of the first switching element or the second switching element, the second switching element is kept on for a predetermined time to discharge the second capacitor element, and after the elapse of the predetermined time Acquiring the second voltage from the second voltage sensor and determining whether the acquired second voltage is 0 or less than a preset threshold, It is determined whether or not a break has occurred in at least one of the third lines.

  Another aspect of the present invention is the balance correction device, wherein the control circuit has a disconnection in at least one of the first line, the second line, and the third line. When the determination is made, the on / off control of the first switching element or the second switching element for the equalization is stopped.

  Another aspect of the present invention is the above power storage device, comprising the plurality of power storage cells and any one of the balance correction devices.

  In addition, the subject which this application discloses, and its solution method are clarified by the column of the form for inventing, and drawing.

  ADVANTAGE OF THE INVENTION According to this invention, the balance correction apparatus and electrical storage apparatus which can detect the disconnection which arose in the circuit with the simple structure reliably can be provided.

2 is an example of a balance correction circuit 1; It is a flowchart explaining disconnection diagnosis processing S200. It is a figure which shows a mode that the disconnection has arisen in the 3rd track | line. It is a figure which shows a mode that the disconnection has arisen in the 2nd track | line. It is a figure which shows a mode that the disconnection has arisen in the 1st track | line.

  Hereinafter, embodiments of the present invention will be described. In the following description, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted.

  FIG. 1 shows a balance correction circuit 1 (balance correction apparatus) shown as an embodiment of the present invention. The balance correction circuit 1 includes, for example, a power storage device (an electric vehicle, a hybrid vehicle, an electric motorcycle, a railway vehicle, a lift, a power storage device for system linkage, a personal computer, a notebook computer) that uses an assembled battery composed of a plurality of power storage cells connected in series. (Book type computer, mobile phone, smartphone, PDA device, etc.). The power storage cell is, for example, a lithium ion secondary battery, a lithium ion polymer secondary battery, or the like, but may be another type of power storage element such as an electric double layer capacitor.

  When manufacturing quality and the degree of deterioration differ between the storage cells that make up the assembled battery, battery characteristics (battery capacity, discharge voltage characteristics) may vary between storage cells. Thus, the voltage between the storage cells may vary during charging and discharging. Therefore, in order to suppress the occurrence of such variation, the balance correction circuit 1 equalizes the voltage between the storage cells or the voltage between the storage modules composed of a plurality of storage cells connected in series (ensuring cell balance). To work.

  As shown in the figure, in this balance correction circuit 1, an assembled battery 3 is constituted by two storage cells B1 and B2 connected in series. The positive and negative terminals 31 and 32 of the assembled battery 3 include, for example, a current supply source (for example, a charger, a regenerative circuit, etc.) that supplies a charging current to the assembled battery 3 and a load that functions using the electromotive force of the assembled battery 3. (For example, a motor, an electronic circuit, an electrical product, etc.) are connected.

  As shown in the figure, the balance correction circuit 1 includes storage cells B1, B2, switching elements S1, S2, resistance elements R1, R2, capacitive elements C1, C2, voltage sensors (voltmeters) VM1, VM2, and a control. A circuit 10 is included.

  A first discharge unit U1 having a configuration in which a switching element S1 and a resistance element R1 functioning as a discharge element are connected in series is connected between the positive and negative terminals of the power storage cell B1, thereby the first circuit (power storage cell B1 , A connection point J1, a connection point J2, a first discharge unit U1, a connection point J6, a connection point J7, and a negative electrode of the storage cell B1 are connected in this order).

  In addition, a second discharge unit U2 having a configuration in which a switching element S2 and a resistance element R2 functioning as a discharge element are connected in series is connected between the positive and negative terminals of the storage cell B2, whereby the second circuit (storage cell) B2 positive electrode, connection point J7, connection point J6, second discharge unit U2, connection point J9, connection point J8, and the negative electrode of the storage cell B2 are connected in this order).

  As shown in the figure, the line connecting the connection point J6 and the connection point J7 is common to both the first circuit and the second circuit.

  The switching elements S1 and S2 are turned on and off by a control signal supplied from the control circuit 10 to each gate. The switching elements S1 and S2 are configured using, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or a bipolar transistor.

  A voltage sensor VM1 is connected between the positive and negative terminals of the storage cell B1. A capacitive element C1 is connected between the positive and negative terminals of the storage cell B1 in parallel with the voltage sensor VM1. The capacitive element C1 plays a role of smoothing the voltage input to the voltage sensor VM1.

  A voltage sensor VM2 is connected between the positive and negative terminals of the storage cell B2. A capacitive element C2 is connected between the positive and negative terminals of the storage cell B2 in parallel with the voltage sensor VM2. The capacitive element C2 plays a role of smoothing the voltage input to the voltage sensor VM2.

  As shown in the figure, the control circuit 10 includes a voltage measurement unit 101, a voltage equalization control unit 102, and a disconnection diagnosis unit 103. The control circuit 10 includes, for example, a microcomputer including an arithmetic device (CPU (Central Processing Unit), MPU (Micro Processing Unit), etc.) and a storage device (RAM (Random Access Memory), ROM (Read Only Memory), etc.). Can be implemented as hardware or software.

  The voltage measurement unit 101 acquires a voltage V1 that is a measurement value of the voltage sensor VM1 and a voltage V2 that is a measurement value of the voltage sensor VM2 via an A / D converter included in the control circuit 10, and the acquired voltage V1 and The voltage V2 is input to the voltage equalization control unit 102 and the disconnection diagnosis unit 103 as needed.

  Specifically, the voltage equalization control unit 102 is based on the voltage V1 and the voltage V2 input from the voltage measurement unit 101 so that the voltage between the terminals of the storage cell B1 and the storage cell B2 is equalized. The switching elements S1 and S2 are controlled to be turned on and off so that the terminal voltage difference is 0 or the absolute value of the terminal voltage difference is not more than a predetermined threshold.

  For example, when the voltage between the terminals of the storage cell B1 is higher than the voltage between the terminals of the storage cell B2, the voltage equalization control unit 102 controls the switching element S1 to be on and the switching element S2 to be off to control the storage cell B1. The electric charges are discharged so that the voltage between the terminals of the storage cell B1 and the storage cell B2 is equalized.

  In addition, for example, when the voltage between the terminals of the storage cell B2 is higher than the voltage between the terminals of the storage cell B1, the voltage equalization control unit 102 controls the switching element S1 to be turned off and the switching element S2 to be turned on to thereby store the storage cell B2. Are discharged so that the voltage between the terminals of the storage cell B1 and the storage cell B2 is equalized.

  In addition, the voltage equalization control unit 102 adjusts the voltage V1 and the voltage V2 so that the voltage between the storage cells B1 and B2 is appropriately equalized from the viewpoint of improving the speed, safety, efficiency, and the like. The on / off of the switching elements S1, S2 is controlled according to the value.

  The disconnection diagnosis unit 103 controls one or more of the switching elements S1 and S2 while the voltage equalization control unit 102 stops the control, and maintains one or more of the switching elements S1 and S2 in an on or off state, respectively. By acquiring the voltages V1 and V2 from the voltage measuring unit 101 for the pattern of the above, the lines constituting the balance correction circuit 1, specifically, the positive electrode of the storage cell B1 including the connection point J1 and the connection point J2 The positive electrode (or the negative electrode of the storage cell B1) and the discharge unit U2 (or the discharge unit) including the line (hereinafter referred to as the first line) connecting the discharge unit U1 and the connection point J6 and the connection point J7. U1), a line connecting the negative electrode of the storage cell B2 and the discharge unit U2 (hereinafter referred to as the second line), the connection point J8 and the connection point J9. At least one of the line referred) now determines whether a disconnection has occurred.

<Disconnection diagnosis processing>
Next, a mechanism for disconnection diagnosis performed mainly by the control circuit 10 will be described. FIG. 2 is a flowchart for explaining processing (hereinafter referred to as disconnection diagnosis processing S200) performed by the control circuit 10 in disconnection diagnosis. Hereinafter, the disconnection diagnosis processing S200 will be described with reference to FIG.

  As shown in the figure, the control circuit 10 monitors in real time whether or not the timing for performing the disconnection diagnosis has arrived. When it is detected that the timing for performing the disconnection diagnosis has arrived (S211: YES), the control circuit 10 performs control for voltage equalization of the storage cells B1, B2 performed mainly by the voltage equalization control unit 102. Cancel and start the processing from S212. For example, when the preset date / time has arrived, or when a preset standby period has elapsed, the user performs a disconnection diagnosis start instruction operation via an input interface or the like provided in the control circuit 10. It comes when, etc.

  In the processing of S212 to S217, the control circuit 10 determines whether or not a break has occurred in the second or third line.

  First, the control circuit 10 controls the switching element S1 to be off and the switching element S2 to be on (S212). Then, after waiting for a discharge time which is a time necessary for discharging the charge accumulated in the capacitive element C2 (S213), a measured value of the voltage V2 is obtained from the voltage sensor VM2 (S214).

  Here, if no disconnection occurs in either the second line or the third line, the voltage V2 has a value corresponding to the voltage between the terminals of the storage cell B2. However, for example, as shown in FIG. 3 or FIG. 4, if a disconnection occurs in at least one of the second line and the third line (in this example, the disconnection part 81 or the disconnection part 82 is disconnected), the discharge The voltage between the terminals of the unit U2 becomes equal, and the voltage V2 becomes 0 or less than a preset threshold (for example, a value sufficiently smaller than the voltage between the terminals of the storage cell B2).

  Therefore, if the voltage V2 is 0 or less than a preset threshold value (S215: YES), the control circuit 10 determines that at least one of the second line and the third line is broken. This is stored as a diagnosis result (S216). If the voltage V2 is not 0 or less than a preset threshold value (S215: NO), the control circuit 10 determines that no disconnection has occurred in either the second line or the third line, and this is determined. The diagnosis result is stored (S217). Thereafter, the process proceeds to S220.

  The reason why the charge stored in the capacitive element C2 is discharged after waiting for the discharge time in the process of S213 is that at least one of the second line and the third line is disconnected. If there is a period during which the capacitive element C2 is charged before, there is a possibility that electric charge remains in the capacitive element C2, and the voltage between the terminals of the capacitive element C2 affects the measurement value of the voltage sensor VM2. This is because it is impossible to correctly determine whether or not the third line is disconnected. Therefore, for example, when a disconnection diagnosis is performed under a situation where it is clear that there is no period during which the capacitive element C2 has been charged in the past, such as when there is a disconnection in the third line from the beginning of manufacture of the balance correction circuit 1. Does not necessarily require the processing of S213. In addition, when the disconnection has arisen in the 3rd track | line, the charge path | route of the capacitive element C2 is cut off. Therefore, by controlling the switching element S2 to be turned on in S212, the charge remaining in the capacitive element C2 is changed from the connection point J5 → the connection point J6 → the switching element S2 → the resistance element R2 → the connection point J9 → the connection point J10. It will be discharged by this path. When the disconnection occurs in the second path, the positive electrode of the storage cell B1 → the connection point J1 → the connection point J3 → the capacitive element C1 → the connection point J5 → the capacitive element C2 → the connection point J10 → the connection point J8 → the storage cell. A charging path for the capacitive element C2 is generated along the path of the negative electrode B2. However, since the charging current at that time is very small, by controlling the switching element S2 to be ON in S212, the charge of the capacitive element is changed from the connection point J5 to the connection point J6 → the switching element S2 → the resistance element. It is discharged along the path from J9 to connection point J10.

  In the processing of S220 to S224, the control circuit 10 determines whether or not a disconnection has occurred in the first line.

  First, the control circuit 10 controls the switching element S1 to be on and the switching element S2 to be off (S220). Then, after waiting for a discharge time which is a time necessary for discharging the electric charge accumulated in the capacitive element C1 (S221), a measured value of the voltage V1 is obtained from the voltage sensor VM1 (S222).

  Here, if no disconnection occurs in the first line, the voltage V1 becomes a value corresponding to the voltage between the terminals of the storage cell B1. However, as shown in FIG. 5, for example, when the first line is disconnected (in this example, the disconnection portion 83 is disconnected), the voltage between the terminals of the discharge unit U1 becomes equal, and the voltage V1 is 0. Or it becomes below the threshold value (for example, value sufficiently smaller than the voltage between terminals of electrical storage cell B1) set beforehand.

  Therefore, if the voltage V1 is 0 or less than a preset threshold value (S223: YES), the control circuit 10 determines that a disconnection has occurred in the first line, and stores this as a diagnosis result (S224). . If the voltage V1 is not 0 or less than a preset threshold value (S223: NO), the control circuit 10 determines that no disconnection has occurred in the first line, and stores this as a diagnostic result (S225). . Thereafter, the process proceeds to S226.

  The reason why the charge accumulated in the capacitive element C1 is discharged after waiting for a predetermined time in the process of S221 is that there is a period during which the capacitive element C1 is charged before the disconnection occurs in the first line. In this case, electric charge may remain in the capacitive element C1, and the voltage between the terminals of the capacitive element C1 affects the measurement value of the voltage sensor VM1 and correctly determines whether or not a disconnection has occurred. Because it becomes impossible to. Therefore, for example, when a disconnection diagnosis is performed in a situation where it is clear that there is no period during which the capacitive element C1 has been charged in the past, such as when there is a disconnection in the first line from the beginning of manufacture of the balance correction circuit 1. The process of S221 is not always necessary. In addition, when the disconnection has arisen in the 1st track | line, the charge path | route of the capacitive element C1 is cut off. Therefore, by controlling the switching element S1 to be turned on in S220, the charge remaining in the capacitive element C1 is changed from the connection point J3 → the connection point J2 → the switching element S1 → the resistance element R1 → the connection point J6 → the connection point J5. It will be discharged by this path.

  As described above, in the balance correction circuit 1 of the present embodiment, the switching elements S1 and S2 and the voltage sensor provided to equalize the voltage of the storage cell B1 and the voltage of the storage cell B2. By using VM1 and VM2, it is possible to diagnose whether or not a break occurs in the first to third lines. For this reason, is the disconnection generated in the first to third lines only by adding the function of the disconnection new stage 103 to the control circuit 10 without adding a special circuit to the configuration of a general balance correction circuit? It is possible to easily realize a mechanism for determining whether or not. For this reason, the balance correction circuit 1 can be simplified and downsized.

  Since the balance correction circuit 1 diagnoses the presence or absence of disconnection after discharging the capacitive elements C1 and C2, disconnection occurs in the first to third lines while suppressing the influence of charges remaining in the capacitive elements C1 and C2. It can be accurately determined whether or not.

  In addition, description of embodiment described above is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

  For example, in the disconnection diagnosis processing S200 shown in FIG. 2, the determination of the presence or absence of disconnection of the first to third lines is performed as a series of flows, but the determination of the presence or absence of disconnection of each of the first to third lines is performed. It is not always necessary to perform all at once, and may be performed individually at independent timing. When determining whether or not the first to third lines are disconnected as a series of flows, the order of determining whether or not the first to third lines are disconnected is not necessarily limited to the order of the disconnection diagnosis processing S200 illustrated in FIG. There is no need.

  The balance correction circuit of the present invention may be provided separately from the storage cell, or may be integrated with the storage cell to form a battery pack or the like.

  DESCRIPTION OF SYMBOLS 1 Balance correction circuit, 10 Control circuit, 101 Voltage measurement part, 102 Voltage equalization control part, 103 Disconnection diagnostic part, C1, C2 capacitive element, B1, B2 electrical storage cell, S1, S2 switching element, R1, R2 resistance element, U1, U2 discharge unit, VM1, VM2 Voltage sensor

Claims (5)

In an assembled battery composed of a plurality of power storage cells connected in series, a balance correction device for equalizing a voltage between the power storage cells or between power storage modules composed of a plurality of power storage cells connected in series,
The first switching element and the first discharge element connected between the positive and negative terminals of the first power storage module among the first power storage module and the second power storage module connected in series before and after. A first discharge unit including a configuration connected in series;
A second discharge unit including a configuration in which a second switching element and a second discharge element are connected in series, connected between positive and negative terminals of the second power storage module;
In order to equalize the first voltage that is the voltage between the terminals of the first power storage module and the second voltage that is the voltage between the terminals of the second power storage module, the first switching element or the first A control circuit for controlling on and off of the two switching elements;
A first voltage sensor for measuring the first voltage;
A second voltage sensor for measuring the second voltage;
With
The control circuit includes:
Obtaining the first voltage or the second voltage for one or more patterns in which the first switching element or the second switching element is maintained on or off, respectively;
A first line that is a line connecting the positive electrode of the first power storage module and the first discharge unit based on the acquired first voltage or the second voltage, and a positive electrode of the second power storage module And at least one of a second line that is a line connecting the second discharge unit and a third line that is a line connecting the negative electrode of the second power storage module and the second discharge unit, Balance correction device that determines whether or not a disconnection has occurred. The balance correction apparatus according to claim 1,
A first capacitive element connected between the terminals of the first power storage module;
The control circuit sets the first switching element to discharge the first capacitor element after stopping the on / off control of the first switching element or the second switching element for the equalization. The time is kept on, and after the predetermined time has elapsed, the first voltage is acquired from the first voltage sensor, and whether or not the acquired first voltage is 0 or less than a preset threshold value. A balance correction device that determines whether or not a disconnection has occurred in the first line. The balance correction apparatus according to claim 1 or 2,
A second capacitor connected between the terminals of the second power storage module;
The control circuit sets the second switching element to discharge the second capacitor element after stopping the on / off control of the first switching element or the second switching element for the equalization. The time is kept on, and after the lapse of the predetermined time, the second voltage is acquired from the second voltage sensor, and whether or not the acquired second voltage is 0 or less than a preset threshold value A balance correction device that determines whether or not a break has occurred in at least one of the second line and the third line. The balance correction device according to any one of claims 1 to 3,
When the control circuit determines that at least one of the first line, the second line, and the third line is disconnected, the first switching element for the equalization Or the balance correction apparatus which stops on-off control of a said 2nd switching element.   A power storage device comprising the plurality of power storage cells and the balance correction device according to any one of claims 1 to 4.

Images