JP2017175836A - Voltage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify a disconnected cell voltage detection wiring.SOLUTION: A voltage detector (A) includes: three or more discharge circuits B1-Bn respectively connected in parallel to battery cells C1-Cn of a battery in which three or more battery cells C1-Cn are connected in series; four or more transmission lines S1 to Sn+1 which transmit the terminal voltage of each terminal of the battery cells C1-Cn; and three or more cell voltage detector units D1-Dn which detect terminal voltages input from the transmission lines S1 to Sn+1, as cell voltages V1-Vn of the battery cells C1-Cn. The voltage detector further includes a microcomputer 1 which acquires the respective absolute values of one pair of cell voltage differences in regard to one pair of battery cells when the discharge circuit of a pair of mutually neighboring battery cells is made into a discharge state with a different duty ratio, so as to determine a disconnected transmission line on the basis of the magnitude relation of the absolute values of the differences.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a voltage detection device.

  The following Patent Document 1 includes a discharge circuit that includes a series circuit of a bypass resistor and a switching element and is connected in parallel to each of a plurality of battery cells that form a battery, and a voltage detection circuit that detects each voltage of the battery cells. And a control unit that controls each switching element so that the voltage of each battery cell becomes uniform based on the voltage detection result of each battery cell obtained from the voltage detection circuit, the control unit includes: The switching element of the discharge circuit connected to the adjacent battery cell is controlled with different duty ratios, and the cell voltage detection wiring drawn from each terminal of each battery cell based on the potential difference between the pair of adjacent battery cells A cell balance control device for detecting disconnection of a cell is disclosed.

  In this cell balance control device, as described in FIG. 2 of Patent Document 1, among the battery cells connected in series with each other, the discharge circuit of the odd-numbered battery cell is discharged at a duty ratio of 4%. The discharge circuit of the even-numbered battery cell is discharged with a duty ratio of 96%. For example, when a disconnection occurs in the cell voltage detection wiring connected to the contact point between the negative terminal of the first battery cell and the positive terminal of the second battery cell, the cell voltage corresponding to the first battery cell increases. In addition, the cell voltage corresponding to the second battery cell decreases, and as a result, the potential difference between the pair of cell voltages corresponding to the first and second battery cells gradually increases. In this cell balance control device, it is determined that a disconnection has occurred in the cell voltage detection wiring when the potential difference between the pair of cell voltages exceeds a predetermined threshold position.

JP 2013-085354 A

  However, in the above background art, it is possible to detect the occurrence of disconnection of the cell voltage detection wiring, but it is not possible to narrow down which of the plurality of cell voltage detection wirings is disconnected. That is, since the cell voltage corresponding to the second battery cell falls, the potential difference between the pair of cell voltages corresponding to the second and third battery cells eventually exceeds the predetermined threshold position. Although it can be detected that a disconnection has occurred in the detection wiring, the disconnected cell voltage detection wiring cannot be specified.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to specify a disconnected cell voltage detection wiring.

  In order to achieve the above object, in the present invention, as a first solution means for a voltage detection device, three or more discharge circuits in which three or more battery cells are connected in parallel to the battery cells of a battery connected in series, respectively. And four or more transmission lines that transmit the terminal voltage of each terminal of the battery cell, and three or more cell voltage detectors that detect the terminal voltage input from the transmission line as a cell voltage of the battery cell. In the voltage detection device, the absolute values of the difference between the pair of cell voltages for the pair of battery cells when the discharge circuits of the pair of battery cells adjacent to each other are in a discharge state with different duty ratios, respectively. A means of including a disconnection determination unit that determines a transmission line that is disconnected based on the magnitude relationship of the absolute values of the differences is employed.

  In the present invention, as the second solving means relating to the voltage detecting device, a means is used in which the cell voltage that cannot be normally detected due to the disconnection of the transmission line is supplemented in the first solving means.

  In the present invention, as a third solving means relating to the voltage detecting device, in the second solving means, the cell voltage that cannot be normally detected is supplemented by a value obtained by dividing the output voltage of the battery by the number of the battery cells. , Is adopted.

  In the present invention, as a fourth solving means relating to the voltage detecting device, a means is used in which the cell voltage that cannot be normally detected is complemented by the average value of the cell voltages that can be normally detected in the second solving means. .

 According to the present invention, there are two or more pairs of battery cells adjacent to each other, and the magnitude relationship between the absolute values of the difference between the pair of cell voltages obtained by discharging the discharge circuits of the pair of battery cells with different duty ratios. By comparison, the disconnected cell voltage detection wiring can be specified.

1 is a system configuration diagram of a vehicle travel system in an embodiment of the present invention. It is a characteristic view which shows the change of the cell voltage in the voltage detection apparatus A which concerns on one Embodiment of this invention. It is a characteristic view which shows the disconnection detection process of the voltage detection apparatus A which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The vehicle traveling system in the present embodiment is provided in a vehicle that obtains a driving force for traveling by driving a motor with electric power, such as an electric vehicle or a hybrid vehicle. As shown in FIG. A detection device A, a main contactor 1, a sub contactor 2, a battery ECU 3, a voltage detection unit 4, an inverter 5 and a motor 6 are provided.

  The battery X is obtained by connecting a plurality of battery modules x1 in which n battery cells C1 to Cn are connected in series, and the plus terminal of the uppermost battery cell C1 of the uppermost battery module x1 is one output terminal. (Plus output terminal), and the minus terminal of the lowest battery cell Cn of the highest battery module x1 is the other output terminal (minus output terminal).

  That is, the battery X includes a plurality of battery modules x1 connected in series in the order of battery cell C1, battery cell C2, battery cell C3, battery cell C4, (omitted), and battery cell Cn. The sum of the inter-terminal voltages of the battery cells C1 to Cn is the output voltage. The “n” is a natural number of 3 or more.

  The voltage detection device A is mounted on a printed circuit board having a predetermined size different from that of the battery X. The voltage between the terminals of the n battery cells C1 to Cn, that is, the difference between the potential of the plus terminal and the potential of the minus terminal. Are detected as cell voltages V1 to Vn, and the cell voltages V1 to Vn are output to the battery ECU 3. The voltage detection device A includes n discharge circuits B1 to Bn, n + 1 transmission lines S1 to Sn + 1, n + 1 CR filters F1 to Fn + 1, n cell voltage detection units D1 to Dn, and a microcomputer M. Yes. Of the components of each voltage detection device A, the microcomputer M corresponds to a disconnection determination unit in the present invention.

  In FIG. 1, only one battery module x1 is shown because of the drawing space limitation, and only four battery cells C1 to C4 are shown among n battery cells C1 to Cn related to the battery module x1. . 1 shows only one voltage detection device A, the voltage detection device A is provided for each battery module x1.

  Further, in FIG. 1, n discharge circuits B1 to Bn, n + 1 transmission lines S1 to Sn + 1, n + 1 CR filters F1 to Fn + 1, and n cell voltage detection units D1 to D1 for one voltage detection device A. Among Dn, voltages of four battery cells C1 to C4, four discharge circuits B1 to B4, five transmission lines S1 to S5, five CR filters F1 to F5, and four cell voltage detectors D1 Only -D4 is shown.

  The n discharge circuits B1 to Bn are provided corresponding to the n battery cells C1 to Cn, and are connected in parallel to the battery cells C1 to Cn, respectively. Each of the n discharge circuits B1 to Bn is a series circuit of a bypass resistor and a switching element as illustrated. The discharge circuits B1 to Bn 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, 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. Yes.

  The n + 1 transmission lines S1 to Sn + 1 are wirings (cell voltage detection wirings) that transmit the terminal voltages of the n battery cells C1 to Cn to the n + 1 CR filters F1 to Fn + 1. The terminals (total n + 1) of the battery cells C1 to Cn and the input terminals (total n + 1) of the n + 1 CR filters F1 to Fn + 1 are connected to each other.

  That is, the transmission line S1 connects the positive terminal of the battery cell C1 and the input end of the CR filter F1, and the transmission line S2 is the contact between the negative terminal of the battery cell C1 and the positive terminal of the battery cell C2 and the input of the CR filter F2. Connect the ends. The transmission line S3 connects the contact point between the negative terminal of the battery cell C2 and the positive terminal of the battery cell C3 and the input end of the CR filter F3. The transmission line S4 is connected to the negative terminal of the battery cell C3 and the battery cell C4. The contact with the plus terminal of the CR filter F4 is connected to the input terminal. The transmission line S5 connects the contact point between the negative terminal of the battery cell C4 and the positive terminal of the battery cell C5 (not shown) and the input end of the CR filter F5.

  The n + 1 CR filters F1 to Fn + 1 are noise-removing low-pass filters provided in n + 1 transmission lines S1 to Sn + 1, respectively, and include a filter resistor and a filter capacitor. The filter resistor is connected in series to each of n + 1 transmission lines S1 to Sn + 1, and the filter capacitor has one end connected to each of n + 1 transmission lines S1 to Sn + 1 and the other end connected to GND (ground). Potential).

  That is, the CR filter F1 has an input end connected to the transmission line S1, and an output end connected to one input end 1a of the cell voltage detector D1. The CR filter F2 has an input end connected to the transmission line S2, and an output end connected to the other input end 1b of the cell voltage detector D1 and one input end 2a of the cell voltage detector D2. The CR filter F3 has an input end connected to the transmission line S3, and an output end connected to the other input end 2b of the cell voltage detector D2 and one input end 3a of the cell voltage detector D3. The CR filter F4 has an input end connected to the transmission line S4, and an output end connected to the other input end 3b of the cell voltage detector D3 and one input end 4a of the cell voltage detector D4. The CR filter F5 has an input end connected to the transmission line S5, and an output end connected to the other input end 4b of the cell voltage detector D4 and one input end 5a of the cell voltage detector D5 (not shown). ing.

  The n cell voltage detection units D1 to Dn are provided corresponding to the n battery cells C1 to Cn described above, and are input via the transmission lines S1 to Sn + 1 and the CR filters F1 to Fn + 1. Based on the terminal voltage of each battery cell C1-Cn, the voltage between terminals of each battery cell C1-Cn is detected as cell voltage V1-Vn.

  That is, the cell voltage detection unit D1 has the positive potential of the battery cell C1 input to one input terminal 1a via the transmission line S1 and the CR filter F1, and the other input input via the transmission line S2 and the CR filter F2. The difference from the negative potential of the battery cell C1 input to the input terminal 1b is detected as the cell voltage V1. The cell voltage detector D2 has a positive potential of the battery cell C2 input to one input terminal 2a via the transmission line S2 and the CR filter F2, and the other input input via the transmission line S3 and the CR filter F3. A difference from the negative potential of the battery cell C2 input to the end 2b is detected as a cell voltage V2.

  In addition, the cell voltage detection unit D3 includes the positive potential of the battery cell C3 input to one input terminal 3a via the transmission line S3 and the CR filter F3, and the other input input via the transmission line S4 and the CR filter F4. The difference from the negative potential of the battery cell C3 input to the input terminal 3b is detected as the cell voltage V3. The cell voltage detection unit D4 has a positive potential of the battery cell C4 input to one input terminal 4a via the transmission line S4 and the CR filter F4, and the other input input via the transmission line S5 and the CR filter F5. A difference from the negative potential of the battery cell C4 input to the end 4b is detected as a cell voltage V4.

  The microcomputer M is a so-called one-chip microcomputer in which a CPU (Central Processing Unit), a memory, an input / output interface, and the like are integrated, and cell voltages V1 to Vn input from n cell voltage detectors D1 to Dn. A / D conversion is performed to obtain sample values (cell voltage data V1 to Vn), and the cell voltage data V1 to Vn are output to the battery ECU 3.

  In addition, the microcomputer M performs disconnection diagnosis processing for n + 1 transmission lines S1 to Sn + 1 by processing n cell voltages V1 to Vn based on a predetermined disconnection detection program. That is, the microcomputer M outputs an open / close signal (pulse signal) to each of the discharge circuits B1 to Bn, thereby causing the discharge circuits of the battery cells adjacent to each other to be discharged at different duty ratios, and a pair of adjacent batteries in this state. The disconnected transmission line is determined based on the magnitude relationship of the absolute value of the cell voltage difference of the cells (difference voltage absolute value ΔV = | V1−V2 |).

  Further, the microcomputer M includes a voltage detection unit m1 as an internal function. The voltage detector m1 detects the output voltage (module voltage Vm) of the battery module x1. The microcomputer M uses the module voltage Vm as control information in the disconnection diagnosis process, and details thereof will be described in detail in the operation description to be described later.

Here, in the present embodiment, the cell voltage detectors D1 to Dn detect n (natural number of 3 or more) cell voltages V1 to Vn corresponding to the number of the battery cells C1 to Cn, and thus the difference voltage ΔV is There are n-1. That is, the difference voltage absolute value ΔV is the difference voltage absolute value ΔV ₁₂ that is the difference between the cell voltage V1 and the cell voltage V2, the difference voltage absolute value ΔV ₂₃ that is the difference between the cell voltage V2 and the cell voltage V3, the cell voltage. There are a total of n−1 difference voltage absolute values ΔV ₃₄ ,..., Which are the differences between V3 and cell voltage V4.

  The main contactor 1 is an energizing switch having a pair of contacts that change to an open state or a closed state depending on a power supply state to the excitation coil, and one contact is connected to the positive output terminal of the battery X. The other contact is connected to the first input terminal of the inverter 5. The main contactor 1 is set to an open state or a closed state by a drive current supplied from the battery ECU 3 to the excitation coil, thereby connecting / connecting the positive output terminal of the battery X and the first input terminal of the inverter 5. Switch off connection.

  The sub-contactor 2 is an energizing switch having a pair of contacts that change to an open state or a closed state depending on a power supply state to the excitation coil, as in the case of the main contactor 1, and one contact is the above-described contactor. The battery X is connected to the negative output terminal of the battery X, and the other contact is connected to the second input terminal of the inverter 5. The sub-contactor 2 is switched between connection / disconnection between the negative output terminal of the battery X and the second input terminal of the inverter 5 by being set to a closed state or an open state by a drive current supplied from the battery ECU 3.

  The battery ECU 3 is a software control device that controls the main contactor 1 and the sub contactor 2 based on a predetermined battery control program. The battery ECU 3 exchanges signals with a memory in which the battery control program is stored, a CPU (Central Processing Unit) that executes the battery control program, the microcomputer M, the main contactor 1, the sub contactor 2, and the voltage detection unit 4. Equipped with input / output interface.

  That is, the battery ECU 3 is based on various information related to the battery X input from the microcomputer M, the power supply voltage Vk from the battery X input from the voltage detection unit 4, and command information input from a host control system (not shown). A drive current for driving the main contactor 1 and the sub contactor 2 is generated. The battery ECU 3 controls the open / closed state of the main contactor 1 and the sub contactor 2 to set the power supply / non-power supply from the battery X to the inverter 5.

  The voltage detector 4 detects the voltage of the feeding power supplied to the first input terminal and the second input terminal of the inverter 5 through the main contactor 1 and the sub contactor 2 as the battery voltage Vb. The voltage detection unit 4 outputs the battery voltage Vb to the battery ECU 3 as one piece of control information.

  The inverter 5 is a three-phase inverter having a first input terminal, a second input terminal, and first to third output terminals. DC power is input from the battery X to the first input terminal and the second input terminal of the inverter 5. The inverter 5 converts the DC power of the battery X input to the first input terminal and the second input terminal into AC power (three-phase AC power) having a predetermined frequency and three phases (U phase, V phase, W phase). Then, the three-phase AC power is output to the motor 6 from the first to third output ends.

  The motor 6 is a three-phase motor that generates rotational power using the three-phase AC power supplied from the inverter 5 as drive power. The vehicle travels using the rotational power generated by the travel motor 6 as a driving force for travel. Such a traveling motor 6 is, for example, a three-phase DC motor having excellent controllability.

  Next, the operation of the vehicle traveling system in this embodiment, particularly the disconnection diagnosis processing of the transmission lines S1 to Sn + 1 performed by the voltage detection device A will be described in detail.

  In a vehicle provided with this vehicle traveling system, when the driver turns on the ignition switch, this operation instruction is input to the battery ECU 3 via a communication system separately provided in the vehicle. Then, the battery ECU 3 changes the state of the main contactor 1 and the sub contactor 2 from the open state to the closed state in accordance with this operation instruction, thereby feeding the DC power of the battery X to the inverter 5.

  The vehicle starts running when the inverter 5 supplies three-phase AC power to the motor 6 by feeding power from the battery X to the inverter 5. In other words, in this vehicle travel system, the vehicle can travel when the DC power of the battery X is supplied to the inverter 5 by the main contactor 1, the sub-contactor 2 and the battery ECU 3.

  Here, the voltage detection apparatus A according to the present embodiment detects the cell voltages V1 to Vn of the n battery cells C1 to Cn constituting the battery X and sequentially provides them to the battery ECU 3. The battery ECU 3 constantly monitors the operating state of the battery X based on these cell voltages V1 to Vn. That is, the microcomputer M sequentially converts the n cell voltages V1 to Vn sequentially input from the n cell voltage detectors D1 to Dn into cell voltage data V1 to Vn, and converts the cell voltage data V1 to Vn to the battery. Provided to the ECU 3.

  Further, the microcomputer M of the voltage detection device A performs a disconnection diagnosis process for the n + 1 transmission lines S1 to Sn + 1 in addition to the process for detecting the cell voltages V1 to Vn. That is, the microcomputer M outputs discharge signals to the respective discharge circuits B1 to Bn, so that the discharge circuits of adjacent battery cells are discharged at different duty ratios. For example, the microcomputer M discharges the discharge circuits B1, B3,... Corresponding to the odd-numbered battery cells C1, C3,... With a 96% duty ratio switching signal, and the even-numbered battery cells C2. , C4,... Are discharged with an open / close signal having a duty ratio of 4%.

  In such a discharge state of each of the discharge circuits B1 to Bn, for example, a disconnection failure occurs in the transmission line S3 connected to the connection point between the minus terminal of the even-numbered battery cell C2 and the plus terminal of the odd-numbered battery cell C3. In this case, as shown in FIG. 2A, the cell voltage V2 corresponding to the even-numbered battery cell C2 gradually increases from the diagnosis start time t1, and the cell voltage V3 corresponding to the odd-numbered battery cell C3 is diagnosed. The voltage gradually decreases from the start time t1.

An absolute value (difference voltage absolute value ΔV) of a pair of cell voltages corresponding to a pair of adjacent battery cells, for example, a pair of cells corresponding to a pair of battery cells C1 and C2 as shown in FIG. The difference voltage absolute value ΔV ₁₂ between the voltages V1, V2; the difference voltage absolute value ΔV ₂₃ between the pair of cell voltages V2, V3 corresponding to the pair of battery cells C2, C3; and the pair of battery cells C3, C4 focusing on the voltage difference absolute value [Delta] V ₃₄ of the cell voltage V3, V4, at time t2 of the diagnostic start time t1 later, the voltage difference absolute value [Delta] V ₁₂ and the voltage difference absolute value [Delta] V ₃₄ is (| -Δe | = Δe), and the The difference voltage absolute value ΔV ₂₃ is (| + 2Δe | = 2Δe).

That is, the three differential voltage absolute values ΔV ₁₂ , ΔV ₂₃ , and ΔV ₃₄ gradually increase after the diagnosis start time t1, as shown in FIG. 3, but the differential voltage absolute value ΔV _{23 at} time t2 is n−. The difference voltage absolute value ΔV ₁₂ positioned before and the difference voltage absolute value ΔV ₃₄ positioned behind in the array of one difference voltage absolute value ΔV are clearly larger values. Further, such a difference voltage absolute value ΔV ₂₃ is obtained from the cell voltages V2 and V3 of the pair of battery cells C2 and C3 to which the disconnected transmission line S3 is commonly connected.

  On the other hand, when a disconnection failure occurs in the transmission line S3, the discharge circuits B1, B3, ... corresponding to the odd-numbered battery cells C1, C3, ... are discharged with an open / close signal having a duty ratio of 4%, When the discharge circuits B2, B4,... Corresponding to the even-numbered battery cells C2, C4,... Are discharged with an open / close signal having a 96% duty ratio, as shown in FIG. The cell voltage V2 corresponding to the even-numbered battery cell C2 gradually decreases from the diagnosis start time t1, and the cell voltage V3 corresponding to the odd-numbered battery cell C3 gradually increases from the diagnosis start time t1.

In this case, at time t2 of the diagnostic start time t1 later, the difference voltage absolute value [Delta] V ₁₂ and the voltage difference absolute value _{V 34 (| + Δe | =} Δe) , and the differential voltage absolute value [Delta] V ₂₃ is (| -2Δe | = 2Δe). That is, the difference voltage absolute value ΔV ₂₃ is larger than the preceding and following difference voltage absolute value ΔV ₁₂ and the difference voltage absolute value V _{34 in} the array of n−1 difference voltage absolute values ΔV.

  The microcomputer M of the voltage detection device A has a difference between a pair of cell voltages corresponding to a pair of battery cells adjacent to each other with respect to the n cell voltages V1 to Vn sequentially input from the n cell voltage detection units D1 to Dn. That is, n−1 differential voltage absolute values ΔV are acquired (calculated), and the differential voltage absolute value ΔV having a larger or smaller value than the preceding and succeeding one among the n−1 differential voltage absolute values ΔV. Search for. And it determines with the transmission line connected in common with a pair of battery cell regarding the difference voltage absolute value (DELTA) V obtained as a result of this search having disconnected.

  Here, when the transmission line S2 is disconnected rather than the transmission line S3, the discharge circuits B1, B3,... Corresponding to the odd-numbered battery cells C1, C3,. When the discharge circuits B2, B4,... Corresponding to the even-numbered battery cells C2, C4,... Are discharged with an open / close signal having a duty ratio of 4%, the odd-numbered battery cells C1 are discharged. The corresponding cell voltage V2 gradually increases from the diagnosis start time t1, and the cell voltage V3 corresponding to the even-numbered battery cell C2 gradually decreases from the diagnosis start time t1.

As a result, at time t2, the voltage difference absolute value _{ΔV 12 (| + 2Δe | =} 2Δe) , and the difference voltage absolute value _{ΔV 23 (| -Δe | = Δe} ) , and the differential voltage absolute value [Delta] V ₃₄ is "zero" It becomes. That is, in this case, the voltage difference absolute value [Delta] V ₁₂ of the pair of cell voltages V1, V2 is the largest value. Therefore, in this case, the transmission microcomputer M is connected in common to the n-1 difference voltage absolute value difference voltage absolute value [Delta] V ₁₂ for one pair of cells C1 to be the largest value among the [Delta] V, C2 It is determined that the line S2 is disconnected.

On the other hand, when the transmission line S2 is disconnected, the discharge circuits B1, B3,... Corresponding to the odd-numbered battery cells C1, C3,. When the discharge circuits B2, B4,... Corresponding to the even-numbered battery cells C2, C4,... Are discharged with an open / close signal having a duty ratio of 96%, the absolute value of the difference voltage ΔV _{12 at} time t2. (| 2Δe | = 2Δe), the difference voltage absolute value ΔV ₂₃ becomes (| + Δe | = Δe), and the difference voltage absolute value ΔV ₃₄ becomes “zero”.

In this case, the microcomputer M excludes “n” of the n−1 differential voltage absolute values ΔV, and the differential voltage absolute value ΔV ₁₂ that is the smallest value among the remaining differential voltage absolute values ΔV _12. It is determined that the transmission line S2 connected in common to the pair of battery cells C1 and C2 is disconnected. That is, the state where the differential voltage absolute value ΔV is “zero” is a normal state of the transmission line in which no disconnection occurs in the transmission line. Therefore, the microcomputer M excludes the difference voltage absolute value ΔV related to such a normal transmission line and relates to the transmission line in which the difference voltage absolute value ΔV ₁₂ having the smallest value among the remaining difference voltage absolute values ΔV is disconnected. extracted as determines that the transmission line S2 connected in common to the battery cells C1, C2 of pair on the basis of this differential voltage the absolute value [Delta] V ₁₂ is disconnected.

  When the microcomputer M identifies the broken transmission line in this way, the cell voltage related to the broken transmission line is recognized as not being a normal value. Then, the microcomputer M supplements the cell voltage that is recognized as not being a normal value based on the module voltage Vm (the output voltage of the battery X module x1) detected by the voltage detection unit m1. That is, the microcomputer M supplements the cell voltage that is recognized as not normal by the value obtained by dividing the module voltage Vm by the number n of the battery cells C1 to Cn.

  Note that the cell voltage that is not normal may be supplemented using the battery voltage Vb instead of the module voltage Vm. That is, the battery ECU 3 does not compensate for the abnormal cell voltage, but the battery ECU 3 uses the battery voltage Vb input from the voltage detection unit 4 to supplement the cell voltage.

  Furthermore, instead of such a complementing method, a cell voltage that cannot be normally detected may be supplemented by an average value of a plurality of cell voltages that can be normally detected. For example, when the transmission line S2 is disconnected, the cell voltages V1 and V2 do not become normal values, and the average value of the remaining cell voltages V3 to Vn is set as the cell voltages V1 and V2.

  According to this embodiment as described above, it is possible to identify a disconnected transmission line based on the magnitude relationship of the difference voltage absolute value ΔV between a pair of cell voltages related to a pair of adjacent battery cells. Similarly to the transmission line S3 described above, the disconnection can be detected in the same manner for the other transmission lines S1, S2, S4 to Sn.

  Further, according to the present embodiment, since the microcomputer M supplements the cell voltage that cannot be normally detected due to the disconnection of the transmission line, a more appropriate limp home travel (retreat travel) is realized when the transmission line is disconnected. Can do.

X battery x1 battery module A voltage detection device C1 to C4 battery cell B1 to B4 discharge circuit S1 to S5 transmission line F1 to F5 CR filter D1 to D4 cell voltage detection unit M microcomputer (disconnection determination unit)
1 Main contactor 2 Sub contactor 3 Battery ECU
4 Voltage detector 5 Inverter 6 Motor

Claims (4)

Three or more discharge circuits connected in parallel to the battery cells of the battery in which three or more battery cells are connected in series, four or more transmission lines for transmitting terminal voltages of the terminals of the battery cells, and the transmission lines In a voltage detection apparatus comprising three or more cell voltage detection units that detect the terminal voltage input from as a cell voltage of the battery cell,
The absolute values of the difference between the pair of cell voltages for the pair of battery cells when the discharge circuits of the pair of battery cells adjacent to each other are discharged at different duty ratios, respectively, The voltage detection apparatus characterized by including the disconnection determination part which determines the transmission line disconnected based on the magnitude relationship.   The voltage detection apparatus according to claim 1, wherein a cell voltage that cannot be normally detected due to disconnection of the transmission line is supplemented.   The voltage detection apparatus according to claim 2, wherein the cell voltage that cannot be normally detected is supplemented by a value obtained by dividing the output voltage of the battery by the number of battery cells. The voltage detection apparatus according to claim 2, wherein the cell voltage that cannot be normally detected is complemented by an average value of cell voltages that can be normally detected.

Images