JP6187142B2 - Battery monitoring device - Google Patents

Description

  The present invention relates to a battery monitoring device that monitors the state of a battery composed of a plurality of assembled batteries.

  In recent years, high-voltage batteries in which assembled batteries including a plurality of battery cells are connected in series have been used. In order to protect each battery cell included in such a battery, a battery voltage monitoring device that monitors the cell voltage of each battery cell has been proposed.

  For example, in the battery voltage monitoring device described in Patent Document 1, a pair of detection terminals corresponding to the positive electrode and the negative electrode of each battery cell is provided for each battery cell, and the pair of detection terminals provided for each battery cell. The cell voltage applied to is detected. In the battery voltage monitoring device, an RC filter circuit is provided between each of the positive electrode terminal and the negative electrode terminal of each battery cell and a pair of detection terminals provided for each battery cell in order to suppress noise from entering the monitoring circuit. Is provided.

JP 2012-159406 A

  When current flows from the high-voltage battery as described above to the inverter, if the inductance of the wire connecting the assembled battery and the assembled battery is large, an electromotive force is generated in the wire due to a surge current accompanying switching of the inverter. However, in the RC filter circuit provided in Patent Document 1, it is not possible to suppress the electromotive force generated in the wire between the assembled batteries from being transmitted to the monitoring circuit connected to the wire between the assembled batteries. For this reason, noise may enter the power supply line or the ground line of the monitoring circuit, causing the monitoring circuit to malfunction.

  In view of the above circumstances, it is a main object of the present invention to provide a battery monitoring device that can suppress the noise generated in the wire between the assembled batteries from being mixed into the monitoring circuit and suppress the malfunction of the monitoring circuit.

  In order to solve the above-mentioned problems, the present invention is a battery monitoring device for monitoring a state of a battery configured by connecting a plurality of battery cells connected in series with a plurality of battery wires connected in series. A monitoring circuit that has a plurality of connection lines connected between adjacent battery cells or at an end of the assembled battery, and detects a voltage of a battery cell included in a predetermined assembled battery; and the plurality of the monitoring circuits A capacitor having both ends connected to the first connection line and the second connection line among the connection lines of the first connection line and the second connection line, wherein the first connection line and the second connection line are between at least one of the assembled batteries. It is connected between the cells or the end portion across the wire.

  According to the present invention, the capacitor is connected between the first connection line and the second connection line that are connected between the cells across at least one inter-battery wire. Thereby, the electromotive force generated in the inter-battery wire between the first connection line and the second connection line due to the surge current is absorbed by the capacitor. Therefore, it is possible to suppress noise generated in the inter-battery wire from being mixed into the monitoring circuit, and to suppress malfunction of the monitoring circuit.

The figure which shows the structure of the battery monitoring apparatus which concerns on 1st Embodiment. The figure which shows the structure of the battery monitoring apparatus which concerns on 2nd Embodiment. The figure which shows the structure of the conventional battery monitoring apparatus.

  First, a conventional battery ECU 150 (battery monitoring device) for monitoring the state of the main battery will be described with reference to FIG. The battery ECU 150 includes an RC filter circuit 134 for noise removal between the monitoring ICs 121 and 122 that detect the voltage of each battery cell 15 and the stacks 11 and 12.

  The main battery 10 (battery) includes a plurality of stacks 11 and 12 (assembled battery) connected in series by inter-stack wires 17 (inter-assembled battery wires). The stacks 11 and 12 are configured by connecting a plurality of battery cells 15 in series. The main battery 10 is connected to an inverter (not shown) and supplies power to the motor and the like via the inverter.

  Here, when a current flows from the main battery 10 to the inverter, if the inductance of the inter-stack wire 17 is large, an electromotive force is generated in the inter-stack wire 17 due to a surge current accompanying switching of the inverter.

  Since the electromotive force generated in the inter-stack wire 17 cannot be removed by the RC filter circuit 134 provided in the battery ECU 150, the inventor mixes noise in the ground lines and power supply lines of the monitoring ICs 121 and 122, and the monitoring ICs 121 and 122. Focused on the risk of malfunction. Further, when the monitoring ICs 121 and 122 are connected in a daisy chain (solid arrow), the noise superimposed on the ground line of the monitoring IC 122 causes the ground line of the monitoring IC 121 by daisy chain communication as indicated by the dashed arrow. Is transmitted to. When the monitoring ICs 121 and 122 are connected in a daisy chain, the present inventor causes the ground of the monitoring ICs 121 and 122 to fluctuate due to the noise generated in the inter-stack wire 17, thereby causing communication abnormality such as bit corruption. We also paid attention to the danger.

  Hereinafter, each embodiment which implement | achieved the battery monitoring apparatus which suppresses the noise which generate | occur | produced in the wire 17 between stacks mixing in monitoring IC, and can suppress malfunctioning of monitoring IC is demonstrated, referring drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
First, the configuration of a battery ECU 50 (battery monitoring device) that detects the voltage of each battery cell 15 included in the main battery 10 will be described with reference to FIG. The battery ECU 50 includes a plurality of monitoring ICs 21 and 22 (monitoring circuits), an RC filter circuit 34, a protection circuit 35, and a microcomputer 40.

  The microcomputer 40 transmits a control command to the monitoring ICs 21 and 22 and receives the voltage of each battery cell 15 detected by the monitoring ICs 21 and 22 from the monitoring ICs 21 and 22. The microcomputer 40 and the monitoring IC 21 (first monitoring circuit), and the monitoring IC 21 and the monitoring IC 22 (second monitoring circuit) are daisy chain connected. A control command is transmitted from the microcomputer 40 to the monitoring ICs 21 and 22 by daisy chain communication, and the voltage of each battery cell 15 detected by the daisy chain communication is transmitted from the monitoring ICs 21 and 22 to the microcomputer 40.

  The monitoring ICs 21 and 22 include a ground terminal 31, a power supply terminal 32, a plurality of connection lines 36 connected between adjacent battery cells 15 or the ends of the stacks 11 and 12, a multiplexer circuit (not shown), and a flying capacitor circuit. The voltage of the battery cell 15 included in the stack is detected. In the present embodiment, the monitoring IC 21 detects each voltage of the battery cell 15 group included in the stack 11, and the monitoring IC 22 detects each voltage of the battery cell 15 group included in the stack 12.

  Two ends of the connection line 36 provided in each of the monitoring ICs 21 and 22 are connected to the ground terminal 31 and the power supply terminal 32, respectively. The connection line 36 connected to the power supply terminal 32 of the monitoring IC 21 and the connection line 36 connected to the ground terminal 31 of the monitoring IC 22 are respectively connected to both ends of the inter-stack wire 17. The connection line 36 connected to the ground terminal 31 of the monitoring IC 21 and the connection line 36 connected to the power supply terminal 32 of the monitoring IC 22 are connected to the end portions of the stack 11 and the stack 12, respectively.

  Of the connection lines 36 included in the monitoring ICs 21 and 22, the connection lines 36 other than the connection lines 36 connected to both ends of the inter-stack wires 17 are connected to a multiplexer circuit included in the monitoring ICs 21 and 22. The multiplexer circuit is configured by a switch that connects and disconnects each of the connection lines 36 other than the connection line 36 connected to both ends of the inter-stack wire 17 and one of both ends of the flying capacitor included in the flying capacitor circuit. . When the switch of the multiplexer circuit is operated and the connection line 36 connected to both ends of each battery cell 15 and the both ends of the flying capacitor are sequentially connected, the voltage of each battery cell 15 is sequentially detected by the flying capacitor circuit. .

  The main battery 10 may be composed of three or more stacks. Further, the battery ECU 50 may include three or more monitoring ICs. Furthermore, one monitoring IC may not correspond to one stack. For example, one monitoring IC may detect each voltage of the battery cell 15 group included in two stacks.

  The RC filter circuit 34 includes a resistor 34 a and a capacitor 34 b (filter capacitor), and is connected between each connection line 36 and a connection line connected to the ground terminal 31. Specifically, the resistor 34 a is connected to the connection line 36 excluding the connection line 36 connected to the ground terminal 31. The capacitor 34b is connected at both ends to the connection line 36 connected to the ground terminal 31 and the other connection lines 36, respectively. One end of the capacitor 34b is connected to the monitoring ICs 21 and 22 rather than the resistor 34a of the RC filter circuit 34. The RC filter circuit 34 stabilizes the voltage of each battery cell 15 applied to the flying capacitor circuit.

  The protection circuit 35 is composed of a Zener diode, and is connected between adjacent connection lines 36. Therefore, when each connection line 36 is connected between the cells or at the ends of the stacks 11 and 12, the battery cell 15 and the Zener diode are connected in antiparallel. Therefore, when the voltage of the battery cell 15 increases to a predetermined value, a current flows through the Zener diode, and the voltage between the connection lines 36 is maintained below the predetermined value. Therefore, even when the voltage of the battery cell 15 becomes higher than the predetermined value, the monitoring ICs 21 and 22 are not overvoltaged, and the monitoring ICs 21 and 22 are protected.

  The capacitor 33 is a capacitor for removing noise generated in the inter-stack wire 17. The capacitor 33 has both ends connected to a connection line 36a (first connection line) and a connection line 36b (second connection line) among the connection lines 36 provided in the monitoring ICs 21 and 22, respectively. The connection line 36 a is included in the connection line 36 included in the monitoring IC 21, the connection line 36 b is included in the connection line included in the monitoring IC 22, and the connection line 36 a and the connection line 36 b extend across the inter-stack wire 17, respectively. Connected between. Further, both ends of the capacitor 33 are connected to the battery cell 15 side with respect to the resistor 34 a of the RC filter circuit 34.

  Both ends of the capacitor 34 b included in the RC filter circuit 34 are not connected to the cells or the ends of the stacks 11 and 12 via the connection line 36 so as to straddle the inter-stack wires 17. On the other hand, both ends of the capacitor 33 are connected between the cells of the stack 11 and between the cells of the stack 12 via the connection line 36 a and the connection line 36 b so as to straddle the inter-stack wire 17. Therefore, as indicated by the dashed arrow, the noise generated in the inter-stack wire 17 is transmitted to the capacitor 33 via the connection line 36b. Therefore, noise generated in the inter-stack wire 17 is not transmitted to the monitoring ICs 21 and 22.

  The connection line 36a may be any of the connection lines 36 included in the monitoring IC 21. Further, the connection line 36b may be any of the connection lines provided in the monitoring IC 22. Further, when the monitoring ICs 21 and 22 monitor a plurality of stacks, the connection line 36a and the connection line 36b are connected between cells or at the end of the stack so as to straddle two or more inter-stack wires 17. Also good.

  According to 1st Embodiment described above, there exist the following effects.

  The capacitor 33 is connected between the connection line 36 a and the connection line 36 b that are connected between the cells across the at least one inter-stack wire 17. Thereby, the electromotive force generated in the inter-stack wire 17 between the connection line 36 a and the connection line 36 b due to the surge current is absorbed by the capacitor 33. Therefore, it is possible to suppress the noise generated in the inter-stack wire 17 from being mixed into the monitoring ICs 21 and 22, and to suppress the malfunction of the monitoring ICs 21 and 22.

  The capacitor 33 is connected to the connection line 36a and the connection line 36b across the connection line 36 connected to the power supply terminal 32 of the monitoring IC 21, the inter-stack wire 17, and the connection line 36 connected to the ground terminal 31 of the monitoring IC 22. Has been. Therefore, it is possible to suppress noise generated in the inter-stack wire 17 from being superimposed on the power supply terminal 32 of the monitoring IC 21 and the ground terminal 31 of the monitoring IC 22. As a result, malfunction of the monitoring IC 21 and the monitoring IC 22 can be suppressed.

  By causing the capacitor 33 to absorb noise generated in the inter-stack wire 17, it is possible to prevent daisy chain communication from occurring.

  Since both ends of the capacitor 33 are connected to the battery cell 15 side rather than the resistor 34a of the RC filter circuit 34, noise generated in the inter-stack wire 17 is absorbed by the capacitor 33 before flowing to the resistor 34a. . Therefore, it is possible to effectively suppress noise generated in the inter-stack wire 17 from being mixed into the monitoring ICs 21 and 22 by the capacitor 33.

(Second Embodiment)
Next, with reference to FIG. 2, the difference of the configuration of the battery monitoring apparatus according to the second embodiment from the first embodiment will be described. In the present embodiment, the connection line connecting both ends of the capacitor 33 is different from the first embodiment. In the present embodiment, the main battery 10 includes three stacks 11, 12, and 13. The battery ECU 50 includes three monitoring ICs 21, 22, 23 and two capacitors 33a, 33b. In the figure, the stack 13 and the monitoring IC 23 are omitted, but are the same as the stacks 11 and 12 and the monitoring ICs 21 and 22.

  The capacitor 33a includes a connection line 36a (first connection line) connected to the ground terminal 31 of the monitoring IC 21 (first monitoring circuit) and a connection line 36b connected to the ground terminal 31 of the monitoring IC 22 (second monitoring circuit). Both ends are connected to the (second connection line). The connection line 36a and the connection line 36b are connected to the end of the stack 11 and the end of the inter-stack wire 17a on the stack 12 side, straddling the inter-stack wire 17a between the stack 11 and the stack 12. Therefore, as indicated by the dashed arrow, the noise generated in the inter-stack wire 17a is transmitted to the capacitor 33a through the connection line 36b. Therefore, noise generated in the inter-stack wire 17a is not transmitted to the monitoring ICs 21 and 22.

  The capacitor 33b is connected to the connection terminal 36b (first connection line) connected to the ground terminal 31 of the monitoring IC 22 (first monitoring circuit) and to the ground terminal 31 of the monitoring IC 23 (second monitoring circuit). Both ends are connected to the line 36c (second connection line). The connection line 36 connected to the power supply terminal 32 of the monitoring IC 22 and the connection line 36c connected to the ground terminal 31 of the monitoring IC 23 are connected to both ends of the inter-stack wire 17b between the stack 12 and the stack 13, respectively. . Accordingly, the connection line 36b and the connection line 36c are connected to the end on the stack 12 side of the inter-stack wire 17a and the end on the stack 13 side of the inter-stack wire 17b across the inter-stack wire 17b. Therefore, like the noise generated in the inter-stack wire 17a, the noise generated in the inter-stack wire 17b is transmitted to the capacitor 33b through the connection line 36c. Therefore, noise generated in the inter-stack wire 17b is not transmitted to the monitoring ICs 22 and 23.

  The connection line 36b connected to the ground terminal 31 of the monitoring IC 22 is connected to the connection line 36 connected to the power supply terminal 32 of the monitoring IC 21 via the inter-stack wire 17a. Therefore, the capacitor 33a also serves as a bypass capacitor of the monitoring IC 21. Similarly, the connection line 36c connected to the ground terminal 31 of the monitoring IC 23 applies the inter-stack wire 17b and is connected to the connection line 36 connected to the power supply terminal 32 of the monitoring IC 22, so that the capacitor 33b is It also serves as a bypass capacitor for the monitoring IC 22.

According to 2nd Embodiment described above, there exist the following effects further.
The capacitors 33a and 33b for removing noise generated in the inter-stack wires 17a and 17b can also be used as bypass capacitors for stabilizing the power supply of the monitoring ICs 21 and 22.

(Other embodiments)
The present invention is not limited to the description of each embodiment described above, and may be modified as follows.

  One or more monitoring ICs are installed between the monitoring IC 21 including the connection line 36a connected to one end of the capacitor 33 and the monitoring IC 22 including the connection line 36b connected to the other end of the capacitor 33. Also good. Specifically, the battery ECU 50 detects one or more voltages of the battery cell 15 group connected between the battery cell 15 group whose voltage is detected by the monitoring IC 21 and the battery cell 15 group whose voltage is detected by the monitoring IC 22. The monitoring IC may be provided. That is, the capacitor 33 may be connected to the connection line 36 across three or more monitoring ICs. For example, in the second embodiment, both ends of the capacitor 33a may be connected to the connection line 36a and the connection line 36c, respectively. If it does in this way, it can suppress that the noise which generate | occur | produces in the wire 17 between stacks by one capacitor | condenser 33 mixes into three or more monitoring ICs. Therefore, the cost and the mounting area of the capacitor can be reduced.

  The plurality of monitoring ICs and the microcomputer 40 may not be daisy chain connected. Even when each monitoring IC and the microcomputer 40 are connected so that they can communicate with each other, malfunction of the monitoring IC can be suppressed by the capacitor 33.

  DESCRIPTION OF SYMBOLS 10 ... Main battery, 11, 12, 13 ... Stack, 15 ... Battery cell, 17, 17a, 17b ... Wire between stacks, 21, 22, 23 ... Monitoring IC, 33, 33a, 33b ... Capacitor, 36, 36a, 36b , 36c ... connection line, 50 ... battery ECU.

Claims (4)

State of the battery (10) constituted by a plurality of battery cells (15) connected in series and a plurality of battery cells (11, 12, 13) connected in series by inter-battery wires (17, 17a, 17b) A battery monitoring device (50) for monitoring
A monitoring circuit that has a plurality of connection lines (36, 36a to c) connected between the cells of the adjacent battery cells or to the end of the assembled battery, and detects the voltage of the battery cell included in the predetermined assembled battery ( 21, 22, 23),
Capacitors (33, 33a, 33b) whose both ends are respectively connected to the first connection line (36a, 36b) and the second connection line (36b, 36c) among the connection lines of the plurality of monitoring circuits. Prepared,
The first connection line and the second connection line are connected between the cells or the end portion across at least one inter-battery wire ,
The connection line connected to the power supply terminal (32) of the first monitoring circuit (21, 22) of the plurality of monitoring circuits, and the second monitoring circuit (22, 23) of the plurality of monitoring circuits. The connection line connected to the ground terminal (31) of the battery is connected to both ends of the inter-battery wire,
The first connection line is included in the connection line of the first monitoring circuit,
The second connecting line, battery monitoring device according to claim Rukoto included in the connecting line and the second monitoring circuit has. The first connection line is the connection line connected to a ground terminal of the first monitoring circuit;
The battery monitoring device according to claim 1 , wherein the second connection line is the connection line connected to a ground terminal included in the second monitoring circuit. Wherein the first monitoring circuit and the second monitor circuit, the battery monitoring device according to claim 1 or 2 are daisy-chained. An RC filter circuit (34) including a resistor (34a) and a filter capacitor (34b) is connected to the connection line,
Both ends of the capacitor battery monitoring device according to any one of claims 1 to 3 connected to the battery cell side of the resistor of the RC filter circuit.

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