JP6598209B2 - Voltage detector - Google Patents

Description

  The present invention relates to a voltage detection device.

  Patent Document 1 below includes a series circuit of a bypass resistor and a switching element, a plurality of discharge circuits connected in parallel to each battery cell of the assembled battery, a voltage detection circuit that detects a cell voltage of the battery cell, In the cell balance control device that controls each switching element so that the cell voltage becomes uniform based on the cell voltage of the battery cell, the discharge circuits connected to the pair of adjacent battery cells are controlled with different duty ratios, If the difference between the cell voltages of the pair of battery cells at this time exceeds a predetermined determination threshold (for example, 1, 3 V), a disconnection occurs in the wiring drawn from the terminals of each battery cell in order to detect the cell voltage. A cell balance control device that determines that the above has occurred is disclosed.

  Thus, when a disconnection occurs in the wiring, the cell voltages of the pair of battery cells show different change trends. That is, one of the pair of cell voltages gradually decreases and finally decreases below a low-voltage side battery abnormality determination threshold (for example, 0.6 V), and the other of the pair of cell voltages gradually increases and finally In particular, it rises above the high-voltage side battery abnormality determination threshold (for example, 4.5 V). Therefore, the cell balance control device, when the wiring for detecting the cell voltage is disconnected, causes the battery abnormality due to the cell voltage exceeding the low voltage side battery abnormality determination threshold or / and the high voltage side battery abnormality determination threshold. This is notified to the vehicle travel ECU that controls the travel of the vehicle as (abnormality of assembled battery). And vehicle travel ECU will take the measure which prohibits travel of a vehicle, if notification of the occurrence of disconnection of wiring is received via battery ECU.

JP 2013-085354 A

  By the way, disconnection of wiring for detecting a cell voltage (wiring for cell voltage detection) and battery abnormality (abnormality of a battery pack) are different events and are also different in importance. That is, in the case of a battery abnormality (abnormality of the assembled battery) in which the battery cell is overcharged or overdischarged, it is an abnormality that requires urgency, and measures for prohibiting vehicle travel are appropriate. Since the disconnection of the wiring is not an abnormality of the assembled battery itself, the urgency is significantly lower than the abnormality of the battery (abnormality of the assembled battery). It is possible to perform evacuation traveling. Therefore, identifying and detecting disconnection of the cell voltage detection wiring and battery abnormality (abnormality of the assembled battery) is extremely important in realizing more appropriate traveling control of the vehicle.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize more appropriate traveling control of a vehicle.

  In order to achieve the above object, in the present invention, as a first solution means for a voltage detection device, a plurality of discharge circuits each connected in parallel to a plurality of battery cells and comprising a series circuit of a bypass resistor and a switching element A plurality of transmission lines that transmit terminal voltages of the terminals of the plurality of battery cells, and a cell voltage detection unit that detects the cell voltages of the plurality of battery cells based on the terminal voltages input from the transmission lines When the discharge circuits of a pair of adjacent battery cells are discharged at different duty ratios, the voltage of the battery cell itself and the voltage of the battery cell itself are related to the pair of battery cells. An abnormality judgment that identifies and determines disconnection of the transmission line relating to the pair of battery cells or abnormality of the battery cell itself based on a difference between the pair of cell voltages including Comprising a part, to adopt a means of.

  In the present invention, as a second solving means relating to the voltage detecting device, in the first solving means, the abnormality determining unit determines that a difference between the pair of cell voltages is predetermined when the voltage of the battery cell itself is abnormal. A means is adopted in which the disconnection of the transmission line is determined when the disconnection threshold value is exceeded.

  In the present invention, as a third solving means relating to the voltage detecting device, in the first solving means, the abnormality determining unit is configured such that when the voltage of the battery cell itself is abnormal, a difference between the pair of cell voltages is predetermined. If the threshold value of the battery cell is not exceeded, a means is adopted in which an abnormality of the battery cell itself is determined.

  In the present invention, as a fourth solving means relating to the voltage detection device, in the first solving means, the abnormality determination unit may be configured such that the voltage of the battery cell itself is equal to or lower than a lower limit battery abnormality threshold, or an upper limit. A means is adopted in which the voltage of the battery cell itself is determined to be abnormal when it is equal to or greater than the side battery abnormal threshold.

 According to the present invention, a pair of battery cells based on a difference between a voltage of the battery cell itself and a pair of cell voltages including the voltage of the battery cell when the discharge circuits of a pair of adjacent battery cells are discharged at different duty ratios. Therefore, it is possible to realize more appropriate traveling control of the vehicle because the transmission line disconnection or the abnormality of the battery cell itself is identified and determined.

It is a circuit diagram which shows the structure of the cell balance control apparatus A which concerns on one Embodiment of this invention. It is a timing chart which shows the whole operation | movement of the cell balance control apparatus A which concerns on one Embodiment of this invention. It is a flowchart which shows the disconnection detection process in one Embodiment of this invention. It is a timing chart which shows a pair of cell voltage V1, V2 and difference voltage (DELTA) V1 in one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the cell balance control device A according to the present embodiment is a device that detects voltages (cell voltages) of a total of twelve battery cells C1 to C12 that constitute an assembled battery, and prints of a predetermined size. 12 discharge circuits B1 to B12 mounted on the substrate, 13 transmission lines S1 to S13, 13 CR filters F1 to F13, 12 cell voltage detectors D1 to D12, temperature sensor TS, microcomputer M (Abnormality determination unit) and an insulating element IR.

  The twelve battery cells C1 to C12 constitute a series circuit connected in series in a line, the negative terminal of the battery cell C1 is the negative terminal of the assembled battery, and the positive terminal of the battery cell C12 is the assembled battery. Positive terminal. That is, twelve battery cells C1 to C12 are connected in series in the order of battery cell C1 → battery cell C2 → (omitted) → battery cell C11 → battery cell C12, and the total cell voltage of each battery cell C1 to C12. The value is the output voltage of the battery pack.

  The twelve discharge circuits B1 to B12 are respectively connected in parallel to the twelve battery cells C1 to C12, and each is a series circuit of a bypass resistor and a switching element. The discharge circuits B1 to B12 are in a discharge state when the switching element is turned on, and are in a non-discharge state when the switching element is turned off.

  That is, the discharge circuit B1 is connected in parallel to the battery cell C1, and the discharge circuit B2 is connected in parallel to the battery cell C2. The discharge circuit B3 is connected in parallel to the battery cell C3, and the discharge circuit B4 is connected in parallel to the battery cell C4. The discharge circuit B5 is connected in parallel to the battery cell C5, and the discharge circuit B6 is connected in parallel to the battery cell C6. The discharge circuit B7 is connected in parallel to the battery cell C7, and the discharge circuit B8 is connected in parallel to the battery cell C8. The discharge circuit B9 is connected in parallel to the battery cell C9, and the discharge circuit B10 is connected in parallel to the battery cell C10. Further, the discharge circuit B11 is connected in parallel to the battery cell C11, and the discharge circuit B12 is connected in parallel to the battery cell C12.

  The 13 transmission lines S1 to S13 are wires (cell voltage detection wires) for transmitting the terminal voltages of the 12 battery cells C1 to C12 to the 12 cell voltage detectors D1 to D12. The terminals (total 13) of the twelve battery cells C1 to C12 and the input terminals (total 13) of the twelve cell voltage detectors D1 to D12 are connected to each other.

  That is, the transmission line S1 connects the positive terminal of the battery cell C1 and one input end 1a of the cell voltage detector D1, and the transmission line S2 is a connection point between the negative terminal of the battery cell C1 and the positive terminal of the battery cell C2. And the other input terminal 1b of the cell voltage detection unit D1 and one input terminal 2a of the cell voltage detection unit D2.

  The transmission line S3 connects a connection point between the negative terminal of the battery cell C2 and the positive terminal of the battery cell C3, the other input end 2b of the cell voltage detection unit D2, and one input end 3a of the cell voltage detection unit D3. The transmission line S4 (not shown) includes a connection point between the negative terminal of the battery cell C3 and the positive terminal of the battery cell C4, the other input terminal 3b of the cell voltage detector D3, and one input terminal of the cell voltage detector D4 (not shown). 4a is connected.

  Further, the transmission line S5 (not shown) is connected to the other input terminal 4b of the cell voltage detector D4 (not shown) and one of the cell voltage detectors D5 as well as the connection point between the minus terminal of the battery cell C4 and the plus terminal of the battery cell C5. The transmission line S6 (not shown) is connected to the input terminal 5a, and the other input terminal 5b of the cell voltage detector D5 (not shown) and the cell voltage are connected to the negative terminal of the battery cell C5 and the positive terminal of the battery cell C6. One input terminal 6a of the detection unit D6 is connected.

  The transmission line S7 (not shown) is connected to the other input terminal 6b of the cell voltage detector D6 (not shown) and one input terminal of the cell voltage detector D7 as well as the connection point between the negative terminal of the battery cell C6 and the positive terminal of the battery cell C7. The transmission line S8 (not shown) is connected to the other input terminal 7b of the cell voltage detector D7 (not shown) and the cell voltage detector as well as the connection point between the minus terminal of the battery cell C7 and the plus terminal of the battery cell C8. One input terminal 8a of D8 is connected.

  The transmission line S9 (not shown) is connected to the other input terminal 8b of the cell voltage detector D8 (not shown) and one input terminal of the cell voltage detector D9 as well as the connection point between the negative terminal of the battery cell C8 and the positive terminal of the battery cell C9. The transmission line S10 (not shown) is connected to the other input terminal 9b of the cell voltage detector D9 (not shown) and the cell voltage detection, similarly to the connection point between the minus terminal of the battery cell C9 and the plus terminal of the battery cell C10. One input terminal 10a of the part D10 is connected.

  The transmission line S11 (not shown) is connected to the other input terminal 10b of the cell voltage detector D10 (not shown) and one input terminal of the cell voltage detector D11 as well as the connection point between the negative terminal of the battery cell C10 and the positive terminal of the battery cell C11. 11a, the transmission line S12 is connected to the connection point between the negative terminal of the battery cell C11 and the positive terminal of the battery cell C12, the other input terminal 11b of the cell voltage detection unit D11 (not shown), and one of the cell voltage detection unit D12. Are connected to the input terminal 12a. The transmission line S13 connects the negative terminal of the battery cell C12 and the other input end 12b of the cell voltage detection unit D12.

  The thirteen CR filters F1 to F12 are noise-removing low-pass filters provided in the thirteen transmission lines S1 to S13, respectively, and are composed of a filter resistor and a filter capacitor. The filter resistor is connected in series to each of the 13 transmission lines S1 to S13. The filter capacitor has one end connected to each of the 13 transmission lines S1 to S13 and the other end connected to GND (grounding). Potential).

  That is, the CR filter F1 is provided on the transmission line S1, the CR filter F2 is provided on the transmission line S2, the CR filter F3 is provided on the transmission line S3, and the CR filter F4 is provided on the transmission line S4. The CR filter F5 is provided on the transmission line S5, the CR filter F6 is provided on the transmission line S6, the CR filter F7 is provided on the transmission line S7, and the CR filter F8 is provided on the transmission line S8. CR filter F9 is provided in transmission line S9, CR filter F10 is provided in transmission line S10, CR filter F11 is provided in transmission line S11, and CR filter F12 is provided in transmission line S10. The CR filter F13 is provided on the transmission line S13.

  The twelve cell voltage detection units D1 to D12 are provided corresponding to the twelve battery cells C1 to C12, and are based on the terminal voltages of the battery cells C1 to C12 input from the transmission lines S1 to S13. The inter-terminal voltage of each of the battery cells C1 to C12 is detected. That is, each cell voltage detection part D1-D12 detects the difference (difference voltage) of each terminal voltage of each battery cell C1-C12 input from 13 transmission lines S1-S13 as cell voltage V1-V12. Output to the microcomputer M.

  That is, the cell voltage detection unit D1 detects the cell voltage V1 of the battery cell C1 based on a pair of terminal voltages input from the transmission line S1 and the transmission line S2, and the cell voltage detection unit D2 is connected to the transmission line S2. The cell voltage V2 of the battery cell C2 is detected based on a pair of terminal voltages input from the transmission line S3. The cell voltage detection unit D3 detects the cell voltage V3 of the battery cell C3 based on a pair of terminal voltages input from the transmission line S3 and the transmission line S4, and the cell voltage detection unit D4 includes the transmission line S4 and the transmission line. The cell voltage V4 of the battery cell C4 is detected based on the pair of terminal voltages input from S5.

  The cell voltage detector D5 calculates the cell voltage V5 of the battery cell C5 based on a pair of terminal voltages input from the transmission line S5 and the transmission line S6, and the cell voltage detector D6 includes the transmission line S6 and the transmission line. Based on the pair of terminal voltages input from S7, the cell voltage V6 of the battery cell C6 is detected. The cell voltage detector D7 detects the cell voltage V7 of the battery cell C7 based on a pair of terminal voltages input from the transmission line S7 and the transmission line S8, and the cell voltage detector D8 includes the transmission line S8 and the transmission line. The cell voltage V8 of the battery cell C8 is detected based on the pair of terminal voltages input from S9.

  The cell voltage detection unit D9 detects the cell voltage V9 of the battery cell C9 based on a pair of terminal voltages input from the transmission line S9 and the transmission line S10. The cell voltage detection unit D10 includes the transmission line S10 and the transmission line. The cell voltage V10 of the battery cell C10 is detected based on the pair of terminal voltages input from S11, and the cell voltage detector D11 is based on the pair of terminal voltages input from the transmission line S11 and the transmission line S12. The cell voltage V11 of the battery cell C11 is detected, and the cell voltage detector D12 detects the cell voltage V12 of the battery cell C12 based on a pair of terminal voltages input from the transmission line S12 and the transmission line S13.

  The temperature sensor TS detects the temperature (substrate temperature) of the printed circuit board on which each element is mounted, and outputs a temperature signal indicating the substrate temperature to the microcomputer M. The temperature sensor TS is mounted on the printed circuit board in the vicinity of the cell voltage detection units D1 to D12 and the microcomputer M, which are liable to be destroyed or malfunction due to temperature rise. Such a temperature sensor TS is, for example, a thermistor.

  The microcomputer M is a so-called one-chip microcomputer in which a CPU (Central Processing Unit), a memory, an input / output interface, etc. are integrated, and exhibits a predetermined function by executing a voltage detection program stored in the internal memory. To do. The microcomputer M sequentially acquires sample values of the cell voltages V1 to V12 by sampling the cell voltages V1 to V12 input from the cell voltage detection units D1 to D12 at a predetermined sampling period.

  In addition, the microcomputer M stores the sample value in an internal memory and performs a predetermined process according to the voltage detection program, thereby performing a balance control process for the state of charge of each of the battery cells C1 to C12, and each transmission line. Diagnosis processing of S1-S13 and each battery cell C1-C12 is performed.

  That is, the microcomputer M functions as a charge balance adjustment unit that adjusts the charge balance of the plurality of battery cells C1 to C12 by controlling the discharge circuits B1 to B12. The microcomputer M controls the discharge circuits B1 to B12 so that the cell voltages V1 to V12 of the battery cells C1 to C12 are equal.

  In addition, the microcomputer M also functions as an abnormality determination unit that performs a diagnosis process on each of the transmission lines S1 to S13 and the battery cells C1 to C12. The microcomputer M outputs an open / close signal to the switching elements of the discharge circuits B1 to B12 to place the discharge circuits of a pair of adjacent battery cells in a discharged state with different duty ratios, and the pair of battery cells in this state Based on the change tendency of the pair of cell voltages, the disconnection (disconnection abnormality) of the transmission line related to the pair of battery cells and the abnormality (battery abnormality) of the pair of battery cells themselves are identified.

  The microcomputer M is connected to an external battery ECU through an insulating element IR so as to be communicable, and notifies the external battery ECU of the identification result between the disconnection abnormality and the battery abnormality. The insulating element IR is an element for isolating the microcomputer M and the battery ECU, and is, for example, a photocoupler.

  Next, the operation of the cell balance control apparatus A according to the present embodiment will be described with reference to FIGS.

  In the cell balance control apparatus A according to the present embodiment, as shown in FIG. 2, the microcomputer M performs an abnormality diagnosis of each transmission line S <b> 1 to S <b> 13 and each cell in an abnormality detection period and an actual discharge period that are alternately repeated at a constant period. The voltages V1 to V12 are alternately made uniform. That is, the microcomputer M controls the switching elements of the discharge circuit connected to the pair of adjacent battery cells with different duty ratios in the abnormality detection period (for example, 150 ms) from time t1 to time t2.

  For example, the microcomputer M switches the switching elements T1, T3,... Of the discharge circuits B1, B3,..., B11 connected to the odd-numbered battery cells C1, C3,. , T11 is turned ON / OFF at a duty ratio (first duty ratio) of 4%, and switching elements of discharge circuits B2, B4,..., B12 connected to even-numbered battery cells C2, C4,. T2, T4,..., T12 are turned ON / OFF at a 96% duty ratio (second duty ratio).

  Here, when a disconnection occurs in any of the 13 transmission lines S1 to S13, the cell voltages (a pair of cell voltages) related to the disconnected line and adjacent to each other are as described above. When the pair of discharge circuits are controlled at different duty ratios, the reverse change tendency is shown because the CR filters F1 to F12 are provided in the transmission lines S1 to S13, and finally each battery cell C1 to The battery abnormality threshold of C12 is exceeded.

  The battery abnormality threshold values are the lower limit battery abnormality threshold value Vmin and the upper limit battery abnormality threshold value Vmax that are set to determine the abnormality of the battery cells C1 to C12, and each of the battery cells C1 to C12. This is a cell voltage that cannot be reached in the case of normal.

  When attention is paid to the difference voltage between the pair of cell voltages when the disconnection occurs, it gradually increases after the start time t1 of the abnormality detection period and exceeds the disconnection threshold value ΔVth. There are a total of 11 difference voltages, the difference voltage ΔV1 is related to the pair of cell voltages V1 and V2, the difference voltage ΔV2 is related to the pair of cell voltages V2 and V3, (omitted), and the difference voltage ΔV11 is This relates to the pair of cell voltages V11 and V12.

  The disconnection threshold value ΔVth is a difference voltage when the pair of cell voltages change in opposite directions, and is set as a difference voltage before the pair of cell voltages reach the battery abnormality threshold value. Is done. That is, when a disconnection occurs in any of the 13 transmission lines S1 to S13, the voltage of the pair of cells changes with the opposite tendency of change and exceeds the disconnection threshold value ΔVth, and then the lower limit battery abnormality occurs. It exceeds the threshold value Vmin or the upper limit battery abnormality threshold value Vmax.

  For example, when a disconnection occurs in the transmission line S2 that connects the connection point between the battery cell C1 and the battery cell C2 and the cell voltage detection unit D1 and the cell voltage detection unit D2, the transmission line S2 is related to and adjacent to the transmission line S2. The pair of battery cells are a battery cell C1 and a battery cell C2.

  As shown in FIG. 2, after the start time t1 of the abnormality detection period, that is, after the control of the pair of discharge circuits B1, B2 related to the pair of battery cells C1, C2 at different duty ratios, the pair of batteries Of the pair of cell voltages V1 and V2 related to the cells C1 and C2, one cell voltage V1 gradually increases, and the other cell voltage V2 gradually decreases. The difference voltage ΔV1 between the pair of cell voltages V1 and V2 becomes equal to or greater than the disconnection threshold value ΔVth, and then one cell voltage V1 reaches the lower limit battery abnormality threshold value Vmin, and the other cell voltage V2 is The upper limit battery abnormality threshold value Vmax is reached.

  The microcomputer M sequentially takes in the cell voltages V1 to V12 after the start time t1 of the abnormality detection period and sequentially calculates the difference voltages ΔV1 to ΔV11 between a pair of adjacent battery cells. Then, by performing identification processing relating to the cell voltages V1 to V12 and the differential voltages ΔV1 to ΔV11 stored in the internal memory according to the flowchart shown in FIG. 3, the disconnection (disconnection) of the transmission line relating to the pair of battery cells. An abnormality) and an abnormality of the pair of battery cells themselves (battery abnormality).

  That is, the microcomputer M determines whether or not any of the cell voltages V1 to V12 exceeds the upper limit battery abnormality threshold value Vmax (step S1). When the determination is “Yes”, that is, the pair of cell voltages including the cell voltage exceeding the upper limit battery abnormality threshold value Vmax changes in a reverse tendency, and then the pair of cell voltages It is determined whether or not the cell voltage difference voltage exceeds the disconnection threshold value ΔVth (step S2). For example, the pair of cell voltages including the cell voltage V1 is a pair of cell voltages V1 and V2, and the pair of cell voltages including the cell voltage V2 is a pair of cell voltages V1 and V2 and a pair of cell voltages V2 and V3.

  For example, when the cell voltage V1 exceeds the upper limit battery abnormality threshold value Vmax, the microcomputer M determines that the two differential voltages V1 and V2 are opposite to each other with respect to the pair of cell voltages V1 and V2 and the pair of cell voltages V2 and V3. A change tendency is shown, and it is determined whether or not the disconnection threshold value ΔVth is exceeded. Then, when the determination in step S2 is “Yes”, the microcomputer M determines that the transmission line B2 is disconnected when one of the difference voltages V1 exceeds the disconnection threshold value ΔVth, and the other difference voltage V2 is When the disconnection threshold value ΔVth is exceeded, it is determined that the transmission line B3 is disconnected (step S3).

  The microcomputer M determines that the determination in step S2 is “No”, that is, the cell voltage V1 exceeds the upper limit battery abnormality threshold value Vmax, but the pair of cell voltages do not change with a reverse change tendency. If neither the difference voltage ΔV1 or ΔV2 between the pair of cell voltages exceeds the disconnection threshold value ΔVth, it is determined that the battery cell C1 corresponding to the cell voltage V1 has become abnormal (step S4).

  Further, when the determination in step S1 is “No”, the microcomputer M determines whether or not any of the cell voltages V1 to V12 exceeds the lower limit battery abnormality threshold value Vmin ( Step S5). When the determination in step S5 is “Yes”, that is, the microcomputer M indicates that the difference voltage between the pair of cell voltages including the cell voltage exceeding the lower limit battery abnormality threshold value Vmin tends to be opposite to each other, Then, it is determined whether or not the disconnection threshold value ΔVth has been exceeded (step S6).

  For example, when the cell voltage V2 exceeds the lower limit battery abnormality threshold value Vmin, the microcomputer M determines that the two differential voltages V1 and V2 are opposite to each other with respect to the pair of cell voltages V1 and V2 and the pair of cell voltages V2 and V3. A change tendency is shown, and it is determined whether or not the disconnection threshold value ΔVth is exceeded. Then, when the determination in step S6 is “Yes”, the microcomputer M determines that the transmission line B2 is disconnected when one of the difference voltages V1 exceeds the disconnection threshold value ΔVth, and the other difference voltage V2 is If the disconnection threshold value ΔVth is exceeded, it is determined that the transmission line B3 is disconnected (step S7).

  If the determination in step S6 is “No”, that is, the cell voltage V2 has exceeded the lower limit battery abnormality threshold value Vmin, the microcomputer M does not change with the opposite trend of the pair of cell voltages. If neither the difference voltage ΔV1 or ΔV2 between the pair of cell voltages exceeds the disconnection threshold value ΔVth, it is determined that the battery cell C2 corresponding to the cell voltage V2 has become abnormal (step S8).

  Further, when the determination in step S5 described above is “No”, the microcomputer M includes both the upper limit battery abnormality threshold value Vmax and the lower limit battery abnormality threshold value Vmin in each of the cell voltages V1 to V12. When there is nothing exceeding, it determines with each battery cell C1-C12 and each transmission line S2-S12 being normal (step S9).

  According to such a cell balance control apparatus A according to the present embodiment, the abnormality (battery abnormality) of a pair of adjacent battery cells as well as the disconnection (disconnection abnormality) of the transmission line related to the pair of adjacent battery cells. Can be detected separately. For example, when the microcomputer M notifies the other ECU (not shown) that controls the traveling of the vehicle via the external battery ECU of the discrimination result between the disconnection abnormality and the battery abnormality, Performs control for stopping the vehicle, and in the case of disconnection abnormality, it is possible to perform retreat traveling control for retreating the host vehicle. Therefore, according to this cell balance control apparatus A, more appropriate traveling control of the vehicle can be realized.

  When the abnormality detection process in the abnormality detection period from time t1 to t2 is completed, the microcomputer M determines the substrate temperature Ta and each battery obtained from the temperature sensor TS in the next actual discharge period (for example, 500 ms) at time t2-t3. Based on the voltage detection results V1 to V2 of the cells C1 to C12, the switching elements T1 to T12 of the discharge circuits B1 to B12 are controlled so that the voltages of the battery cells C1 to C12 are uniform.

  Then, when the cell balance control in the actual discharge period from time t2 to t3 ends, the microcomputer M differs from the abnormality detection period from time t1 to t2 in the next abnormality detection period from time t3 to t4. , And B11 switching elements T1, T3,..., T11 connected to the battery cells C1, C3,. The abnormality detection processing is performed by turning on / off the switching elements T2, T4,..., T12 of the discharge circuits B2, B4,..., B12 connected to the cells C2, C4,.

  That is, the microcomputer M performs an abnormality detection process by alternately switching the first duty ratio and the second duty ratio for each abnormality detection period, thereby preventing one of adjacent battery cells from being overdischarged. To do. In addition, as shown in FIG. 2, even if the values of the first duty ratio and the second duty ratio are switched, the change tendency of the cell voltage V1 of the battery cell C1 and the cell voltage V2 of the battery cell C2 is only reversed. Yes, disconnection of the transmission lines S2 to S12 can be detected as in the abnormality detection period at times t1 to t2.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) Although the above embodiment relates to a case where the present invention is applied to the cell balance control apparatus A, the present invention is not limited to this. The present invention is also applicable to a voltage detection device that simply detects cell voltages of a plurality of battery cells, for example.

(2) In the above embodiment, the disconnection of each transmission line S2 to S12 is determined by comparing the difference voltage ΔV1 to ΔV11 of a pair of cell voltages in a pair of adjacent battery cells with the disconnection threshold ΔVth. The present invention is not limited to this. For example, when the discharge circuits of a pair of battery cells adjacent to each other are in a discharge state with different duty ratios, each of the pair of cell voltages is based on whether or not they exhibit opposite change trends over a plurality of sample values. The disconnection of the transmission lines S2 to S12 may be determined.

A cell balance control device B1 to B12 discharge circuit C1 to C12 battery cell D1 to D12 cell voltage detection unit F1 to F12 CR filter M microcomputer (abnormality determination unit)
S1 to S13 Transmission line

Claims (3)

A plurality of discharge circuits each connected in parallel to a plurality of battery cells and comprising a series circuit of a bypass resistor and a switching element; a plurality of transmission lines for transmitting terminal voltages of the terminals of the plurality of battery cells; and the transmission In a voltage detection apparatus comprising a cell voltage detection unit that detects a cell voltage of the plurality of battery cells based on the terminal voltage input from a line,
The discharge circuit of a pair of adjacent battery cells is in a discharge state with a different duty ratio , and the cell voltage related to the pair of battery cells is present when the cell voltage that exceeds the upper-limit battery abnormality threshold is present in each cell voltage. An abnormality that identifies and determines disconnection of the transmission line or an abnormality of the battery cell itself with respect to the pair of battery cells based on a difference between the voltage of the battery cell itself and a pair of cell voltages including the voltage of the battery cell itself A voltage detection apparatus comprising a determination unit. The abnormality determination unit, when there is the cell voltage exceeding the upper limit battery abnormality threshold in each cell voltage, when the difference between the pair of cell voltages exceeds a predetermined disconnection threshold, The voltage detection device according to claim 1, wherein disconnection of the transmission line is determined. When the cell voltage exceeding the upper-limit battery abnormality threshold exists in each cell voltage , the abnormality determination unit is a battery cell if the difference between the pair of cell voltages does not exceed a predetermined threshold. The voltage detection apparatus according to claim 1, wherein the abnormality is determined.

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