JP2009216448A - Abnormality detection device for battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality detection device for a battery pack detecting disconnection or fracture of parallel connectors connecting cells. <P>SOLUTION: The device, which detects an abnormality of a battery pack 1 in which two or more parallel cell blocks 11A connecting two or more cells 11 in parallel by a pair of parallel connectors 12, 13 are connected in series, comprises a voltage detection section 3 detecting a voltage between one end of the parallel connector 12 and one end of the parallel connector 12 of a parallel cell block 11B adjacent to the parallel cell block 11A and an abnormality determination CPU4 determining abnormality of the parallel cell blocks based on the detected condition of voltage variation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for detecting an abnormality of an assembled battery.

There is known an assembled battery in which a plurality of parallel cell blocks in which a plurality of cells are connected in parallel are connected in series. In this type of battery pack, the abnormality of the cell is detected, but it is uneconomical to provide a voltage sensor for each cell. For this reason, a voltage sensor is provided in the series circuit part which connects each parallel cell block in series, and abnormality of a cell is determined based on the voltage detected by each voltage sensor (patent document 1).

JP 2006-138750 A

  However, when measuring the voltage of the series circuit unit as in the above-described prior art, the voltage of the series circuit unit is detected as usual even if the parallel connection body that connects each cell of the parallel cell block is disconnected or broken, There is a problem that it is difficult to detect disconnection or the like of the parallel connection body.

The problem to be solved by the present invention is to provide an assembled battery abnormality detection device capable of detecting disconnection or breakage of a parallel connection body connecting cells.

The present invention solves the above problem by detecting a voltage between one end of a parallel connection body of parallel cell blocks and one end of a parallel connection body of parallel cell blocks adjacent thereto. .

  According to the present invention, since the voltage between the end portions of the parallel connection bodies of the parallel cell blocks is detected, it is possible to detect disconnection or breakage of the parallel connection bodies connecting the cells.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram illustrating an assembled battery abnormality detection device according to an embodiment of the present invention. The battery pack abnormality detection device of this example can be applied to batteries used in devices other than vehicles, in addition to batteries for electric vehicles, hybrid vehicles, and engine vehicles. The assembled battery 1 of this example includes four cells (unit cells) 11 as secondary batteries connected in parallel to form four sets of parallel cell blocks 11A to 11D, and these four sets of parallel cell blocks 11A. To 11D connected in series. In this example, four cells 11 are connected in parallel to form four sets of parallel cell blocks 11A to 11D, and an assembled battery 1 in which these four sets of parallel cell blocks 11A to 11D are connected in series is taken as an example. The abnormality detection device will be described by way of example. However, the number of parallel connections of cells in the parallel cell block of the assembled battery 1 that is an abnormality detection target and the number of series connection of parallel cell blocks are not limited to this example.

  The assembled battery 1 is connected to the inverter 92 via the current sensor 7 and the main relay 91, and supplies DC power to the inverter 92. The inverter 92 converts the DC power of the assembled battery 1 into AC power and applies it to the travel drive AC motor 93 to drive the motor 93 and cause the vehicle to travel. The inverter 92 also converts AC regenerative power generated by the motor 93 during braking of the vehicle into DC power and charges the assembled battery 1. The main relay 91 is opened and closed by the CPU 4 to connect and release the assembled battery 1 and the motor 93. The current sensor 7 detects a discharge current flowing from the assembled battery 1 to the inverter 92 and a charging current flowing from the inverter 92 to the assembled battery 1 and outputs the detected current to the CPU 4.

The battery controller includes a CPU 4, a memory (RAM) 5, a voltage sensor 6, a temperature sensor 8, a cell voltage detection unit 3, a capacity adjustment unit 2, and the like, and controls charging / discharging and capacity adjustment of the assembled battery 1. 11 abnormality detection is performed.

The voltage sensor 6 detects the total voltage of the assembled battery 1 and outputs it to the CPU 4. The temperature sensor 8 detects the temperature of the assembled battery 1 and outputs it to the CPU 4.

The cell voltage detector 3 detects an average terminal voltage of the cells 11 connected in parallel to each of the parallel cell blocks 1A to 11D of the assembled battery 1. Details of the cell voltage detector 3 will be described later.

The capacity adjustment unit 2 corrects the battery capacity variation between the parallel cell blocks based on the cell average terminal voltages of the parallel cell blocks 11A to 11D detected by the cell voltage detection unit 3.

  FIG. 2 is an electric circuit diagram showing details of the capacity adjustment unit 2 of this example, and shows one parallel cell block 11A for convenience of explanation. A series circuit of a resistor 21 and a transistor 22 is connected in parallel to the parallel cell block 11A of the assembled battery 1. Although not shown, similarly, a series circuit of a resistor and a transistor is connected in parallel to each of the parallel cell blocks 11B to 11D. Hereinafter, only the operation for the parallel cell block 11A will be described, but the operations for the other parallel cell blocks 11B to 11D are the same.

The series circuit of the resistor 21 and the transistor 22 is a circuit for discharging the charge capacity (SOC: State Of Charge) of the cell 11 in the parallel cell block 11A, the resistor 21 is a discharge resistor, and the transistor 22 is This is a switching element for discharging and stopping. As the switching element, a semiconductor switching element such as an FET, a relay, or the like can be used instead of the transistor 22.

The CPU 4 sends a signal to the base of the transistor 22 of the parallel cell block 11A to control the on (conducting) and off (non-conducting) of the transistor 22. When the transistor 22 is turned on, the charging power of the cell 11 of the parallel cell block 11A is discharged through the resistor 21, and the charging capacity SOC is reduced by the amount of discharge. The CPU 4 performs duty control by repeatedly turning on and off the transistor 22. This duty ratio is determined based on the discharge capacity and discharge time (capacity adjustment time) of the parallel cell block 11A. More specifically, based on the difference between the charge capacity of the parallel cell block 11A and a target charge capacity (details will be described later), a discharge time, which is a time for flowing (discharging) current from the parallel cell block 11A to the resistor 21, is calculated. To do. Then, the duty ratio is determined based on a predetermined time from the start of the capacity adjustment to the end of the capacity adjustment and the discharge time. The predetermined time from the start of capacity adjustment to the end of capacity adjustment is, for example, the capacity adjustment from the start of capacity adjustment of the parallel cell block that takes the longest capacity adjustment among the parallel cell blocks 11A to 11D. If the predetermined time is set, the capacity adjustment of all the parallel cell blocks can be completed at the same time. However, the time is not limited to this, and may be a time determined for the convenience of the system. The time can be set accordingly.

A voltage sensor 23 is connected between the collector and emitter of the transistor 22. When the transistor 22 is turned on, the collector-emitter voltage becomes approximately 0 V, and when the transistor 22 is turned off, the collector-emitter voltage becomes the voltage across the cells of the parallel cell block 11A. The CPU 4 monitors the voltage between the collector and the emitter of the transistor 22 by the voltage sensor 23, and performs capacity adjustment while confirming the operation state of the transistor 22, that is, the capacity adjustment state of the parallel cell block 11A.

The capacity adjustment unit 2 performs capacity adjustment in units of the parallel cell blocks 11A to 11D of the assembled battery 1, and any one of the parallel cell blocks is overcharged or overdischarged, so that the capacity of the assembled battery 1 is sufficiently large. Prevent it from becoming unavailable. That is, if there is a capacity variation in each parallel cell block of the parallel cell blocks 11A to 11D, the parallel cell block with a small charge capacity is likely to be overdischarged due to discharge or charging during load driving, and the parallel cell block with a large charge capacity is Prone to overcharging. In order to prevent this, the output power of the assembled battery 1 is limited when the capacity of the parallel cell block with a small charge capacity may be overdischarged, or the capacity of the parallel cell block with a large charge capacity is overdischarged. If there is a possibility that the input (charge) power to the battery pack 1 is limited, the other parallel blocks can input / output power, but input / output cannot be performed. The capacity of 1 cannot be fully used. Therefore, the capacity adjustment unit 2 sets the target charge capacity so as to reduce the capacity variation of each parallel cell block, and discharges each cell block by discharging so that the charge capacity of each parallel cell block becomes the target charge capacity. Adjust the capacity variation. The target charging capacity is set to a capacity capable of reducing the capacity variation of each parallel cell block, such as a minimum value or an intermediate value among the capacities of all parallel cell blocks.

However, in the parallel cell blocks 11A to 11D in which the four cells 11 are connected in parallel as in this example, the capacity adjustment between the cells 11 in one parallel cell block is adjusted by the capacity adjustment unit 2. It is not possible.

However, the capacity variation between the parallel connection cells in each parallel cell block 11A to 11D is eliminated by the capacity self-adjusting function. That is, if there is a variation in capacity between the four cells 11 connected in parallel, the capacity of the cell 11 on the higher capacity side, that is, the higher terminal voltage side, is lower, that is, the terminal voltage is lower. It gradually moves to the cell 11 on the side, and the four parallel cells have the property of becoming equal capacity. This property is called capacity self-adjustment. The larger the capacity difference (difference in cell open-circuit voltage), the faster the change rate of capacity until the capacity becomes closer to the same capacity, and the capacity difference becomes smaller and closer to the capacity. As a result, the rate of change in capacity becomes slower.

Returning to FIG. 1, in the assembled battery 1 of this example, the four cells 11 of the parallel cell blocks 11 </ b> A to 11 </ b> D are connected in parallel via a pair of parallel connectors 12 and 13. Further, the four parallel cell blocks are connected in series via the serial connection body 14. These parallel connection bodies 12 and 13 and the serial connection body 14 can each be comprised with the bus bar which consists of conductors, a conducting wire, etc., and can be joined to the output terminal of the cell 11 by joining methods, such as welding.

FIG. 3 is a front view showing the cell 11 of this example, and FIG. 4 is a plan view showing the assembled battery 1 of this example. As shown in FIG. 3, the cell 11 of this example is formed such that a positive electrode output terminal 112 and a negative electrode output terminal 113 protrude from one end edge of the cell body 111. The four cells 11 are overlapped with the main surface of the cell body 111 so that the polarities are in the same direction, and the parallel connection body 12 is connected to the four positive output terminals 112 as shown in FIG. The parallel connection body 13 is connected to the terminal 113.

In addition, in FIG. 4, the parallel connection body which connects the positive electrode output terminals 112 of each parallel cell block with respect to four parallel cell blocks 11A-11D is shown by 12A-12D, and the parallel which connects the negative electrode output terminals 113 is shown. As shown by connection parts 13A to 13D, the alphabet at the end was made the same as the alphabet at the end of the parallel cell block. Similarly, in the case of the parallel cell block 11A, the cells 11A1, 11A2, 11A3, and 11A4 are attached to the cell 11 from the left end to the right end, so that one parallel cell block 11A is configured by the numbers at the end. It is shown so that the connection position of the cell 11 can be easily identified.

Although the four parallel cell blocks 11A to 11D are connected in series in this order, the parallel cell block 11A on the positive electrode side shown in FIG. 4 and the parallel cell block 11B adjacent thereto are connected by a series connection body 14AB. The parallel cell block 11B and the parallel cell block 11C adjacent thereto are connected by a series connection body 14BC, and the parallel cell block 11C and the parallel cell block 11D adjacent thereto are connected by a series connection body 14CD. . These connection positions are output terminal portions of the cells 11A4, 11B4, 11C4, and 11D4 located at the right ends of the parallel cell blocks 11A to 11D. However, the connection positions of the series connection bodies 11AB, 11BC, and 11CD can be the output terminal portions of the cells 11A1, 11B1, 11C1, and 11D1 located at the left ends of the parallel cell blocks 11A to 11D.

The positive electrode side output terminal 15 of the battery pack 1 is connected to the right end portion (position of the positive electrode output terminal 112 of the cell 11A4) of the parallel connection body 12A of the parallel cell block 11A on the positive electrode side, while the negative electrode side is connected in parallel. The negative output terminal 16 of the assembled battery 1 is connected to the right end of the parallel connection body 13D of the cell block 11D (position of the negative output terminal 113 of the cell 11D4).

Here, in the assembled battery 1 of this example, the voltage detection positions P1 to P5 of the cell voltage detection unit 3 are set to the left ends (4 of P1 to P4) of the positive electrode side parallel connection bodies 12A to 12D of the parallel cell blocks 11A to 11D. ) And the left end (one place of P5) of the negative electrode side parallel connection body 13D of the negative electrode side parallel cell block 11D. The left end of the parallel connection bodies 12A to 12D, 13D means a position corresponding to the output terminals of the left end cells 11A1, 11B1, 11C1, 11D1 in the configuration of the assembled battery 1 shown in FIG.

However, when the serial connection bodies 14AB, 14BC, and 14CD are provided at the right end as shown in the figure, the voltage detection positions P1 to P5 of the cell voltage detection unit 3 are set to the positive electrodes of the parallel cell blocks 11A to 11D. The left end of the side parallel connection bodies 12A to 12D and the left end of the negative side parallel connection body 13D of the parallel cell block 11D on the negative side, but when the series connection bodies 14AB, 14BC, 14CD are provided at the left end, the cell The voltage detection position of the voltage detector 3 is set to the opposite right end. That is, the voltage detection positions P1 to P5 of the cell voltage detector 3 are provided at the end opposite to the end provided with the series connection bodies 14AB, 14BC, and 14CD that connect the four parallel cell blocks 11A to 11D in series. .

The voltage detection lines drawn from the voltage detection positions P1 to P5 are connected to the voltage detection unit 3, and the voltage Vc1 of the parallel cell block 11A is detected at P1 to P2, and the parallel cell block 11B is detected at P2 to P3. The voltage Vc2 is detected, the voltage Vc3 of the parallel cell block 11C is detected in P3 to P4, and the voltage Vc4 of the parallel cell block 11D is detected in P4 to P5.

Note that the voltage detection position P5 may be the right end of the parallel connection body 13D or the negative electrode side output terminal 16 of the assembled battery 1 instead of the left end of the parallel connection body 13D of the parallel cell block 11D.

The voltages Vc1 to Vc4 of the parallel cell blocks 11A to 11D detected by the cell voltage detection unit 3 are output to the CPU 4, and the CPU 4 determines whether there is an abnormality in the parallel cell block based on the detected voltage fluctuation state. This CPU 4 corresponds to the abnormality determination means of the present invention.

Next, the abnormality detection process according to this example will be described.

FIG. 5 is a flowchart showing the abnormality detection process. First, the total voltage V0 of the assembled battery 1 is acquired by the voltage sensor 6 in step S1.

The acquisition timing of the total voltage V0 may be either when the assembled battery 1 is in an unloaded state or in a loaded state. However, when determining the abnormality by detecting the unloaded total voltage V0, the total voltage acquired in step S6 The voltage V0 ′ is also preferably a no-load voltage after traveling. This is because, when a load is connected to the secondary battery and the battery capacity is charged and discharged, a voltage drop (IR drop) occurs due to the internal resistance of the cell, so the measured voltage at no load is compared with the load This is because an accurate capacity variation is not known.

  Next, in step S2, the cell voltage detection unit 3 causes the cell voltages Vc1 to Vc4 of the parallel cell blocks 11A to 11D (hereinafter also referred to as Vcn as a representative. The subscript n denotes the parallel cell blocks 11A to 11D. means the voltage of the nth parallel cell block). The measurement order of the cell voltage Vcn is not particularly limited, and the measurement order can be determined and measured one by one, or the voltages of all the parallel cell blocks 11A to 11D can be measured simultaneously.

  In step S3, the current value I0 is measured by the current sensor 7, and in step S4, the temperature T0 of the assembled battery 1 is measured by the temperature sensor 8.

  In the next step S5, it is determined whether or not the predetermined time m has elapsed using the internal timer of the CPU 4.

If the predetermined time m has not elapsed due to the timer, the process returns to step S1 and the processes of steps S1 to S4 are repeated. If the predetermined time m has elapsed, the process proceeds to step S6.

The predetermined time m is a time for comparing the amount of voltage fluctuation when charging / discharging of a predetermined capacity, and it is desirable that the predetermined time m is set to be appropriately long. Further, the predetermined time m by the timer can be changed according to the state of the charge capacity SOC of the assembled battery 1.

For example, FIG. 10C is a graph showing the relationship of the cell open voltage with respect to the charging capacity SOC, and the secondary battery has a large voltage fluctuation in the range of 30% or less and 70% or more, and the SOC is 30 to 70. In the range of%, the voltage variation is small. If the charge capacity state has a large voltage fluctuation, the voltage fluctuation that can be detected is expected even if the predetermined time m by the timer is reduced. However, when the charge capacity state has a small voltage fluctuation, the voltage fluctuation cannot be detected in a short predetermined time. There is a fear. Therefore, in the range of the charge capacity SOC where the voltage fluctuation is small, the voltage fluctuation can be reliably detected by setting the predetermined time m longer by the timer than in the range of the charge capacity SOC where the voltage fluctuation is large.

The relationship of the predetermined time m with respect to the charge capacity SOC is stored in the memory 5 in advance, and the CPU 4 obtains the charge capacity SOC from the total voltage V0 detected in step S1, and determines the obtained charge capacity SOC. Based on this, a predetermined time m which is a voltage fluctuation determination time is set. The CPU 4 and the voltage sensor 6 correspond to the charge capacity detection means of the present invention.

  In the next step S6, as in step S1, the voltage sensor 6 measures the total voltage V0 ′ after a predetermined time m has elapsed.

  In step S7, similarly to step S2, the cell voltage Vcn ′ after a predetermined time m has been measured by the cell voltage detector 3 is measured.

  In step S8, as in step S3, the current I0 ′ after the predetermined time m has been measured by the current sensor 7 is measured.

In step S9, as in step S4, the temperature T0 ′ after the predetermined time m has elapsed is measured by the temperature sensor 8.

In the next step S10, the total voltage Vo measured in step S1 is compared with the total voltage V0 'measured after the predetermined time m measured in step S6, and whether or not the absolute value of the fluctuation amount is equal to or greater than the threshold value α (| V0−V0 ′ | ≧ α) is determined.

This threshold value α is a limit value of a fluctuation amount for confirming whether or not the assembled battery 1 has performed charging / discharging of a predetermined capacity, and depends on the number of parallel cell blocks 11A to 11D constituting the assembled battery 1 in series. It can be set appropriately.

Further, the threshold value α can be appropriately changed by multiplying the deterioration coefficient k1 corresponding to the degree of deterioration of the assembled battery 1 or the temperature coefficient k2 corresponding to the temperature of the assembled battery 1, thereby more accurately determining the assembled battery 1. The voltage fluctuation amount can be detected.

FIG. 10A is a graph showing the relationship of the deterioration coefficient k1 to the degree of deterioration of the battery, and FIG. 10B is a graph showing the relationship of the temperature coefficient k2 to the battery temperature. When the battery deteriorates, the amount of voltage fluctuation increases, and when the battery temperature increases, the amount of voltage fluctuation decreases. Therefore, as shown in FIG. 3A, the deterioration coefficient k1 with respect to the degree of deterioration of the battery is set to 100% when the battery is new, and the deterioration coefficient k1 is increased with the passage of time. Further, as shown in FIG. 5B, the temperature coefficient k2 with respect to the battery temperature is 100% when the standard temperature is 20 ° C., and the temperature coefficient K2 is decreased as the temperature rises.

Although not shown, since the sensitivity of the voltage sensor 6 varies depending on the temperature, the sensitivity coefficient k3 of the voltage sensor is set to 100% at the standard temperature, and the sensitivity coefficient k3 at a higher or lower temperature is made smaller. You can also

The deterioration coefficient k1, the temperature coefficient k2, or the sensitivity coefficient k3 is stored in the memory 5 in advance, and the CPU 4 multiplies the threshold value α by these coefficients k1, k2, and k3 when executing the process of step S10. Change the threshold appropriately. That is, if the determination in step S10 is performed with | V0−V0 ′ | ≧ α · k1 · k2 · k3, the voltage fluctuation amount of the assembled battery 1 can be detected more accurately.

The threshold α and a threshold obtained by appropriately multiplying the α by the deterioration coefficient k1, the temperature coefficient k2, and the sensitivity coefficient k3 correspond to the first determination threshold of the present invention.

If the voltage fluctuation amount of the assembled battery 1 is greater than or equal to the threshold value α in step S10, the process proceeds to step S11. On the other hand, when the voltage fluctuation amount of the assembled battery 1 is less than the threshold value α, that is, when a sufficient amount of charging / discharging is not performed, the capacity fluctuation of the cell 11 is not expected sufficiently, and therefore abnormality determination is performed. The process is finished without.

  Next, in step S11, the cell voltage Vcn measured in step S2 is compared with the cell voltage Vcn ′ measured after elapse of the predetermined time m measured in step S7, and whether the absolute value of the variation is equal to or less than the threshold value β. Whether (| Vcn−Vcn ′ | ≧ β) is determined.

This threshold value β is a limit value for determining whether or not the parallel connection bodies 12 and 13 have an abnormality in disconnection or breakage. The cell voltage detection unit 3 and the capacity adjustment unit 2 consume power even during a predetermined time m. Therefore, it is desirable from the viewpoint of detection accuracy to set the smallest possible value in consideration of this amount. This threshold value β corresponds to the second determination threshold value of the present invention. Similar to the threshold value α described above, a value obtained by multiplying the threshold value β by a deterioration coefficient k1 corresponding to the degree of deterioration of the battery or a temperature coefficient k2 corresponding to the battery temperature can be used as the threshold value.

Here, in the assembled battery 1 of this example, when there is an abnormality such as disconnection or breakage in the parallel connection bodies 12 and 13, the voltage fluctuation amount of the parallel cell blocks 11 </ b> A to 11 </ b> D detected by the cell voltage detection unit 3. Either it is equal to zero or the amount of variation is greater than normal. And in this step S11, the disconnection abnormality of the parallel connection bodies 12 and 13 is detected by detecting that the voltage fluctuation amount of parallel cell block 11A-11D is substantially zero.

  This point will be described with reference to FIG.

FIG. 6A is a diagram in which portions of the assembled battery 1 and the cell voltage detection unit 3 of this example are extracted, and FIG. 6B is a diagram showing fluctuations in the total voltage V0 of the assembled battery 1 over time and abnormal parallelism. It is a graph which shows the voltage Vc1 of a cell block, and the voltage Vc2 of a normal parallel cell block. An abnormal parallel cell block is 11A, and a normal parallel cell block is 11B. Then, as shown in FIG. 6A, at time ta, the positive-side parallel connection body 12A of the parallel cell block 11A that has been normal so far is cut at the portion Z1 between the cells 11A2 and 11A3. To do.

As shown in the upper diagram of FIG. 5B, when the battery pack 1 is discharged at a predetermined capacity from time t1 to time t2, the total voltage at the discharge start time t1 is V0, and the cell voltages are Vc1 to Vc4. . If the assembled battery 1 is normal, the total voltage at t2 after a predetermined time m is V0 ′, the cell voltages are Vc1 ′ to Vc4 ′, and when the total voltage fluctuation amount is ΔV0 from the predetermined time t1 → t2, the cell voltage Voltage fluctuation amount ΔVc1 = ΔVc2 = ΔVc3 = ΔVc4 should be satisfied.

However, when the positive electrode side parallel connection body 12A is cut at the portion Z1 as shown in FIG. 5A, the cell 11A1 of the parallel cell block 11A is discharged although the assembled battery 1 is discharged as a whole. , 11A2 is not discharged because the parallel connection body 12A on the positive electrode side is disconnected. The voltage of the parallel cell block 11A detected by the cell voltage detection unit 3 (V1 shown in FIG. 3A) is the potential between the positive electrode of the cell 11A1 and the positive electrode of the cell 11B1 of the parallel cell block 11B, That is, since it becomes the open circuit voltage of the cells 11A1 and 11A2, no voltage fluctuation is detected.

That is, when the positive electrode side parallel connection body 12A is disconnected, the cell voltage detection unit 3 detects the voltages of the cells 11A1 and 11A2 that are no longer discharged due to disconnection. The same applies to the case where the cut site is between the cells 11A1 and 11A2 and between the cells 11A3 and 11A4. The same applies to the parallel cell blocks 11B to 11C other than the parallel cell block 11A shown in FIG. However, the disconnection abnormality of the parallel connection bodies 12D and 13D of the parallel cell block 11D will be described later.

Returning to FIG. 5, in the next step S12, it is determined whether or not the parallel cell block in which the abnormality is detected is the lowest cell block 11D. The lowest level here means that the voltage detection positions P1 to P5 by the cell voltage detection unit 3 are both the same parallel cell block positions.

That is, in this example, one of the voltage detection positions P1 of the parallel cell block 11A is the parallel cell block 11A, while the other P2 is the adjacent parallel cell block 11B. On the other hand, the voltage detection positions P4 and P5 of the parallel cell block 11D are both the parallel cell block 11D. The disconnection abnormality of the parallel cell block 11D is different from the disconnection abnormality of the other parallel cell blocks 11A to 11C as follows.

  That is, in the lowest parallel cell block 11D, the voltage detection positions P4 and P5 are set to both the positive and negative parallel connection bodies 12D and 13D, and one of the parallel connection bodies 12D and 13D is disconnected or broken. If there is an abnormality, the voltage fluctuation of the parallel cell block 11D becomes almost zero. FIG. 7 is a diagram illustrating a case where the parallel connection bodies 12D and 13D of the parallel cell block 11D are disconnected. At time ta, the positive-side parallel connection body 12D of the parallel cell block 11D that has been normal so far is replaced with the cell 11D3. And at the time ta, the negative-side parallel connection body 13D of the parallel cell block 11D that has been normal until then is cut at the portion Z3 between the cells 11D2 and 11D3. Indicates the case. However, it is not cut | disconnected simultaneously in part Z2, Z3, but is cut | disconnected by either one.

  When the positive electrode side parallel connection body 12D is cut at the portion Z2 as shown in FIG. 6A, the cells 11D1 to 11D3 of the parallel cell block 11D are discharged although the assembled battery 1 is discharged as a whole. Is not discharged because the parallel-connected body 12D on the positive electrode side is disconnected. The voltage of the parallel cell block 11D (V4 shown in FIG. 4A) detected by the cell voltage detector 3 is the potential between the positive electrode and the negative electrode of the cell 11D1, that is, the open voltage of the cells 11D1 to 11D3. Therefore, voltage fluctuation is not detected.

On the other hand, when the negative side parallel connection body 13D is cut at the portion Z3 as shown in FIG. 5A, the cell 11D1 of the parallel cell block 11D is discharged although the assembled battery 1 is discharged as a whole. , 11D2 are not discharged because the parallel connection 13D on the negative electrode side is disconnected. The voltage of the parallel cell block 11D detected by the cell voltage detector 3 (V4 shown in FIG. 3A) is the potential between the positive electrode and the negative electrode of the cell 11D1, that is, the open voltage of the cells 11D1 and 11D2. Therefore, in this case as well, no voltage fluctuation is detected.

Thus, in the lowest parallel cell block 11D, it cannot be identified whether the positive or negative parallel connection bodies 12D and 13D are disconnected.

  Therefore, when it is determined in step S12 of FIG. 5 that the cell is the lowest parallel cell block 11D, the process proceeds to step S13, and at least one of the positive and negative electrodes of the lowest parallel cell block 11D is paralleled. It is determined that the connection bodies 12D and 13D are disconnected abnormally.

  On the other hand, when it is not the lowest parallel cell block 11D in step S12, it progresses to step S14 and determines with the disconnection abnormality of the parallel connection body 12 of the positive electrode side of the said parallel cell block concerned.

  This is because, in this example, when there is a disconnection abnormality in the parallel cell blocks 11A to 11C other than the lowest one, either the positive electrode or the negative electrode can be specified. This will be described below.

  Returning to step S11, if the absolute value (| Vcn−Vcn ′ |) of the fluctuation amount of the cell voltage exceeds the threshold value β in step S11, the process proceeds to step S15.

  In step S15, it is determined whether or not the absolute value of the variation amount of the cell voltage is greater than or equal to a threshold value γ (| Vcn−Vcn ′ | ≧ γ).

  This threshold value γ is a limit value for determining whether or not the parallel connection bodies 12 and 13 have an abnormality in disconnection or breakage, and sets a maximum fluctuation amount in which a normal parallel cell block fluctuates by charging / discharging for a predetermined time m in advance. can do. This threshold value γ corresponds to the third determination threshold value of the present invention. Similar to the threshold values α and β described above, a value obtained by multiplying the threshold value γ by a deterioration coefficient k1 according to the degree of deterioration of the battery or a temperature coefficient k2 according to the battery temperature can be used as the threshold value.

  FIG. 8 is a diagram illustrating a case where the negative electrode side parallel connection body 13A of the parallel cell block 11A is disconnected, and at time ta, the negative electrode side parallel connection body 13A of the parallel cell block 11A that has been normal so far is replaced with the cell 11A2. The case where it cut | disconnects by the part Z4 between 11A3 is shown.

When the negative side parallel connection body 13A is cut at the portion Z4 as shown in FIG. 6A, the cells 11A1 and 11A2 of the parallel cell block 11A are disconnected from the negative side parallel connection body 13A. Although not discharged, the cells 11A3 and 11A4 are discharged as much as the undischarged capacity. The voltage of the parallel cell block 11A detected by the cell voltage detection unit 3 (V1 shown in FIG. 3A) is the potential between the positive electrode of the cell 11A1 and the positive electrode of the cell 11B1 of the parallel cell block 11B, That is, since the voltages of the cells 11A3 and 11A4 are obtained, the voltage fluctuation is larger than that in the normal state.

On the other hand, when the positive electrode side parallel connection body 12A is cut as indicated by Z1 in FIG. 6A, the voltage of the parallel cell block 11A does not vary as described above.

  Thus, when there is a disconnection abnormality in the parallel cell blocks 11A to 11C other than the lowest, it is possible to specify either the positive electrode or the negative electrode.

  Returning to step S15 in FIG. 5, if the absolute value of the variation amount of the cell voltage is less than the threshold value γ, the process is terminated. If the absolute value of the cell voltage is greater than or equal to the threshold value γ, the process proceeds to step S16. It is determined that the connection body 13A is abnormally disconnected.

  As described above, according to the assembled battery abnormality detection device of the present embodiment, not the position of the serially connected bodies 14AB, 14BC, and 14CD of the parallel cell blocks 11A to 11D but one of the positive side parallel connected bodies 12A to 12D. Since the voltage detection positions P <b> 1 to P <b> 5 are used as the end portions of the parallel connection bodies 13 </ b> D and the negative electrode side parallel connection body 13 </ b> D, the disconnection abnormality of the parallel connection bodies 12 and 13 can be detected.

  Moreover, about the parallel cell blocks 11A-11C, since one edge part of each positive electrode side parallel connection body 12A-12D is made into voltage detection position P1-P4, in addition to the detection of the disconnection abnormality of the parallel connection bodies 12 and 13, It is also possible to identify whether the disconnection abnormality of the positive electrode side parallel connection body 12 or the disconnection abnormality of the negative electrode side parallel connection body 13.

In the above-described embodiment, the cell voltage detection positions P1 to P4 are one end of the positive electrode side parallel connection bodies 12A to 12D of the parallel cell blocks 11A to 11D. However, as shown in FIG. One end P6 to P9 of the negative electrode side parallel connection bodies 13A to 13D of the blocks 11A to 11D and one end portion P10 of the positive electrode side parallel connection body 12A of the parallel cell block 11A can also be used. FIG. 9 is a block diagram showing a main part of an abnormality detection apparatus for an assembled battery according to another embodiment. In the case of this example, the determination in step S14 of FIG. 5 is a disconnection abnormality of the negative side parallel connection body, and the determination of step S16 is a disconnection abnormality of the positive side parallel connection body.

<< Second Embodiment >>
FIG. 11 is a block diagram showing an assembled battery abnormality detection device according to still another embodiment of the present invention, and FIG. 12 is a plan view showing the assembled battery according to this embodiment.

  In the embodiment described above, the series connection bodies 14AB, 14BC, and 14CD that connect the four parallel cell blocks 11A to 11D in series are provided at the right end of the parallel connection bodies 12 and 13 of each parallel cell block. It is provided at the center of the parallel connection bodies 12 and 13 of the parallel cell blocks 11A to 11D. This is shown in a plan view as shown in FIG.

  That is, each series connection body 14AB, 14BC, 14CD is connected so as to be located in the middle of the two cells 11 at the center of the four cells 11. Since other configurations are the same as those of the embodiment shown in FIGS. 1 to 3, the description thereof is incorporated herein.

Next, the abnormality detection process according to this example will be described.

FIG. 13 is a flowchart showing the abnormality detection process of this example. In this example, the determination result differs from the above-described embodiment depending on the cutting positions of the parallel connectors 12 and 13. This point will be described with reference to FIG.

In the assembled battery 1 shown in the figure, it is assumed that a disconnection abnormality has occurred in each of the four locations Y1 to Y4 of the parallel cell block 11A and the four locations Y5 to Y8 of the lowest parallel cell block 11D.

First, when disconnection occurs at the position Y1 of the positive electrode side parallel connection body 12A of the parallel cell block 11A, the discharge of the cell 11A1 is stopped, but the cell voltage detection unit 3 detects the open voltage of the cell 11A1, so the voltage fluctuation amount Is almost zero. That is, a behavior corresponding to FIG. 6 of the above-described embodiment is observed.

On the other hand, when disconnection occurs at the position Y2 of the positive electrode side parallel connection body 12A of the parallel cell block 11A, the discharge of the cell 11A4 stops, but the discharge amount of the other three cells 11A1 to 11A3 increases by the capacity. In addition, the cell voltage detector 3 detects the voltages of the three cells 11A1 to 11A3 whose discharge amount has increased. Therefore, the amount of voltage fluctuation detected by the cell voltage detection unit 3 increases compared to the normal time. That is, a behavior corresponding to FIG. 8 of the above-described embodiment is observed.

Further, when disconnection occurs at the position Y3 of the negative electrode side parallel connection body 13A of the parallel cell block 11A, the discharge of the cell 11A1 stops, but the discharge amount of the other three cells 11A2 to 11A4 increases by the capacity. The cell voltage detector 3 detects the voltages of the three cells 11A2 to 11A4 whose discharge amount has increased. Therefore, the amount of voltage fluctuation detected by the cell voltage detection unit 3 increases compared to the normal time. That is, a behavior corresponding to FIG. 8 of the above-described embodiment is observed.

Further, when disconnection occurs at the position Y4 of the negative electrode side parallel connection body 13A of the parallel cell block 11A, the discharge of the cell 11A4 stops, but the discharge amount of the other three cells 11A1 to 11A3 increases by the capacity, The cell voltage detector 3 detects the voltages of the three cells 11A1 to 11A3 whose discharge amount has increased. Therefore, the amount of voltage fluctuation detected by the cell voltage detection unit 3 increases compared to the normal time. That is, a behavior corresponding to FIG. 8 of the above-described embodiment is observed.

On the other hand, when disconnection occurs at the position Y5 of the positive electrode side parallel connection body 12D of the lowest parallel cell block 11D, the discharge of the cell 11D1 is stopped, but the cell voltage detection unit 3 detects the open voltage of the cell 11D1. The voltage fluctuation amount becomes almost zero. That is, a behavior corresponding to FIG. 6 of the above-described embodiment is observed.

In addition, when the disconnection occurs at the position Y7 of the positive electrode side parallel connection body 12D of the parallel cell block 11D, the discharge of the cell 11D1 is stopped, but the cell voltage detection unit 3 detects the open voltage of the cell 11D1. The voltage fluctuation amount becomes almost zero. That is, a behavior corresponding to FIG. 6 of the above-described embodiment is observed.

  In contrast, when disconnection occurs at the position Y6 of the positive electrode side parallel connection body 12D of the parallel cell block 11D, the discharge of the cell 11D4 stops, but the discharge amount of the other three cells 11D1 to 11D3 increases by the capacity. In addition, the cell voltage detector 3 detects the voltages of the three cells 11D1 to 11D3 whose discharge amount has increased. Therefore, the amount of voltage fluctuation detected by the cell voltage detection unit 3 increases compared to the normal time. That is, a behavior corresponding to FIG. 8 of the above-described embodiment is observed.

  In addition, when disconnection occurs at the position Y8 of the positive electrode side parallel connection body 12D of the parallel cell block 11D, the discharge of the cell 11D4 stops, but the discharge amount of the other three cells 11D1 to 11D3 increases by the capacity. In addition, the cell voltage detector 3 detects the voltages of the three cells 11D1 to 11D3 whose discharge amount has increased. Therefore, the amount of voltage fluctuation detected by the cell voltage detection unit 3 increases compared to the normal time. That is, a behavior corresponding to FIG. 8 of the above-described embodiment is observed.

  Returning to FIG. 13, the processing contents from step S <b> 1 to S <b> 11 are the same as those in the above-described embodiment, and the description thereof is omitted here, and the subsequent processing from step S <b> 12 will be described.

  In the next step S12, it is determined whether the parallel cell block in which the abnormality is detected is the lowest cell block 11D. As in the above-described embodiment, the lowest level here means that the voltage detection positions P1 to P5 by the cell voltage detection unit 3 are both the positions of the same parallel cell block.

  If it is not the lowest parallel cell block 11D in step S12, the process proceeds to step S14, and it is determined that there is a disconnection abnormality at the position Y1 of the positive electrode side parallel connection body 12 of the parallel cell block. In this example, it is possible to specify the cutting position until it is the position on the cell voltage detection position side from the connection position of the series connection body 14 in the positive electrode side parallel connection body 12.

  If it is the lowest cell block 11D in step S12, the process proceeds to step S13, and the disconnection abnormality occurs at the position Y5 of the positive side parallel connection body 12D of the parallel cell block 11D or the position Y7 of the negative side parallel connection body 13D. It is determined that That is, in this example, the cutting position can be specified up to the position closer to the cell voltage detection position than the connection position of the series connection body 14.

  Returning to step S11, if the absolute value (| Vcn−Vcn ′ |) of the fluctuation amount of the cell voltage exceeds the threshold value β in step S11, the process proceeds to step S15. In step S15, the fluctuation amount of the cell voltage. It is determined whether or not the absolute value of is greater than or equal to the threshold γ (| Vcn−Vcn ′ | ≧ γ).

  Here, if the absolute value of the fluctuation amount of the cell voltage is less than the threshold value γ, the process is terminated. If the absolute value is greater than or equal to the threshold value γ, the process proceeds to step S16, and the parallel cell block in which abnormality is detected is the lowest cell block 11D. Determine if.

If it is not the lowest parallel cell block 11D in step S16, the process proceeds to step S18, and it is determined that there is a disconnection abnormality at positions Y2 to Y4 other than the position Y1 of the positive electrode side parallel connection body 12 of the parallel cell block. .

If it is the lowest cell block 11D in step S16, the process proceeds to step S17, and the disconnection abnormality occurs at position Y6 of the positive side parallel connection body 12D or position Y8 of the negative side parallel connection body 13D of the parallel cell block 11D. It is determined that That is, in this example, the cutting position can be specified up to the position opposite to the cell voltage detection position side from the connection position of the series connection body 14.

  As described above, according to the assembled battery abnormality detection device of the present embodiment, not the position of the serially connected bodies 14AB, 14BC, and 14CD of the parallel cell blocks 11A to 11D but one of the positive side parallel connected bodies 12A to 12D. Since the voltage detection positions P <b> 1 to P <b> 5 are used as the end portions of the parallel connection bodies 13 </ b> D and the negative electrode side parallel connection body 13 </ b> D, the disconnection abnormality of the parallel connection bodies 12 and 13 can be detected.

  Further, for the parallel cell block 11D, in addition to the detection of the disconnection abnormality of the parallel connection bodies 12 and 13, it is also possible to identify which side is the disconnection abnormality with respect to the series connection body 14. For parallel cell blocks 11A to 11C, in addition to detecting disconnection abnormality of parallel connection bodies 12 and 13, the position of positive electrode side connection body 12 of cell 11 adjacent to the voltage detection position or other positions is identified. You can also

It is a block diagram which shows the abnormality detection apparatus of the assembled battery which concerns on embodiment of this invention. It is an electric circuit diagram which shows the structure of the capacity | capacitance adjustment part of FIG. It is a front view which shows the cell of FIG. It is a top view which shows the assembled battery of FIG. It is a flowchart which shows operation | movement of the abnormality detection apparatus of FIG. It is a figure for demonstrating the process of step S11 of FIG. It is a figure for demonstrating the process of step S13 of FIG. It is a figure for demonstrating the process of step S15 of FIG. It is a block diagram which shows the principal part of the abnormality detection apparatus of the assembled battery which concerns on other embodiment of this invention. (A) It is a graph which shows the relationship of the degradation coefficient k1 with respect to a battery degradation degree, (B) The relationship of the temperature coefficient k2 with respect to battery temperature, (C) The relationship of the cell open circuit voltage with respect to charge capacity, respectively. It is a block diagram which shows the abnormality detection apparatus of the assembled battery which concerns on further another embodiment of this invention. It is a top view which shows the assembled battery of FIG. It is a flowchart which shows operation | movement of the abnormality detection apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Assembly battery 11, 11A1-11A4, 11B1-11B4, 11C1-11C4, 11D1-11D4 ... Cell 11A-11D ... Parallel cell block 12, 12A-12D, 13, 13A-13D ... Parallel connection body 14 ... Series connection body 15, 16 ... Output terminal 2 ... Capacity adjustment unit 3 ... Voltage detection unit (voltage detection means)
4 ... CPU (abnormality determination means, charge capacity detection means)

Claims (10)

An apparatus for detecting an abnormality of a battery pack in which a plurality of cells connected in parallel by a pair of parallel connectors is connected in series in a plurality of blocks,
Voltage detecting means for detecting a voltage between one end of the one parallel connection body and the one end of the one parallel connection body of the parallel cell block adjacent to the parallel cell block;
An abnormality detection device for an assembled battery, comprising: abnormality determination means for determining an abnormality of the parallel cell block based on a voltage fluctuation state detected by the voltage detection means. In the assembled battery abnormality detection device according to claim 1,
The assembled battery includes a series connection body that connects the plurality of parallel cell blocks in series,
The series connection body connects the other end of the other parallel connection body of the parallel cell block and the other end of the one parallel connection body of the parallel cell block adjacent to the parallel cell block. A battery pack abnormality detection device characterized by the above. In the assembled battery abnormality detection device according to claim 1 or 2,
An assembled battery voltage detecting means for detecting the voltage of the assembled battery;
The abnormality determination means determines an abnormality of the parallel cell block based on the voltage fluctuation state detected by the voltage detection means only when the voltage fluctuation amount of the assembled battery is not less than a first determination threshold value. An abnormality detection device for an assembled battery. In the assembled battery abnormality detection device according to any one of claims 1 to 3,
The assembled battery abnormality detection device, wherein the abnormality determination unit determines that the parallel cell block is abnormal when the amount of voltage fluctuation detected by the voltage detection unit is equal to or less than a second determination threshold value. In the assembled battery abnormality detection device according to claim 4,
The abnormality determination unit determines that an abnormality of the parallel cell block is a disconnection abnormality of the one parallel connection body. In the abnormality detection apparatus of the assembled battery as described in any one of Claims 1-5,
The assembled battery abnormality detection device, wherein the abnormality determination unit determines that the parallel cell block is abnormal when the voltage fluctuation amount detected by the voltage detection unit is equal to or greater than a third determination threshold value. In the assembled battery abnormality detection device according to claim 6,
The abnormality determination unit determines an abnormality of the parallel cell block as a disconnection abnormality of the other parallel connection body, and detects an abnormality of the assembled battery. In the assembled battery abnormality detection device according to claim 4 or 5,
Comprising at least one of temperature detecting means for detecting the temperature of the assembled battery or deterioration degree detecting means for detecting the degree of deterioration of the assembled battery;
The assembled battery abnormality detecting device, wherein the abnormality determining means sets the second determination threshold value according to the detected temperature and / or degree of deterioration. In the assembled battery abnormality detection device according to claim 6 or 7,
Comprising at least one of temperature detecting means for detecting the temperature of the assembled battery or deterioration degree detecting means for detecting the degree of deterioration of the assembled battery;
The assembled battery abnormality detection device, wherein the abnormality determination means sets the third determination threshold according to the detected temperature and / or degree of deterioration. In the abnormality detection apparatus of the assembled battery as described in any one of Claims 1-9,
Charge capacity detection means for detecting the charge capacity of the assembled battery,
The abnormality determination device for an assembled battery, wherein the abnormality determination unit sets a voltage state detection period by the voltage detection unit according to the detected charge capacity.

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