JP7428117B2 - Abnormality determination device for battery monitoring equipment - Google Patents

Description

The present invention relates to an abnormality determination device for a battery monitoring device.

A battery pack is constructed by connecting battery cells in multiple stages. Conventionally, a monitoring IC has been provided to monitor these battery cells, and an equalization switch has been provided so that the cell voltages of the battery cells are equalized (for example, see Patent Documents 1 and 2).

In recent years, for the purpose of improving the heat dissipation of the monitoring IC, it has been required to configure the monitoring IC with an external equalization circuit. In the technique described in Patent Document 1, a detection circuit for an equalization switch is provided inside the monitoring IC to detect whether the equalization switch is stuck on.

However, the technique described in Patent Document 1 is a circuit that detects whether the equalization switch built into the monitoring IC is stuck on, and does not provide a means for detecting whether the equalization circuit is stuck on, which is externally attached to the monitoring IC.

Patent No. 6398964

SUMMARY OF THE INVENTION An object of the present invention is to provide an abnormality determination device for a battery monitoring device that is capable of determining an abnormality in an equalization circuit externally attached to a monitoring IC.

The invention according to claim 1 is directed to an abnormality determination device for a battery monitoring device that monitors an assembled battery in which a plurality of battery cells are connected in series. The equalization circuit is configured using an equalization switch provided outside the monitoring IC, and when the equalization switch is turned on, the voltage of the plurality of battery cells is adjusted by energizing the loop path passing through the equalization switch and the battery cells. equalize.

The shunt resistor is configured to be interposed in the circuit path. The determination unit uses a first detection value obtained through a filter so as not to include a voltage drop that occurs in the shunt resistance due to the current flowing in the circuit path, and a first detection value that is obtained through a filter so as not to include a voltage drop that occurs in the shunt resistance due to the current flowing in the circuit path. It is determined whether or not a short-circuit abnormality has occurred in the equalization circuit by comparing the second detection value obtained so as to include the voltage drop that occurs.

When a short circuit occurs in the equalization circuit, current flows through the loop path, causing a voltage drop across the shunt resistor. Therefore, by comparing the first detected value that does not include the voltage drop that occurs in the shunt resistor and the second detected value that includes the voltage drop that occurs in the shunt resistor, it is possible to determine whether a short circuit abnormality has occurred in the equalization circuit. As a result, an abnormality in the equalization circuit externally attached to the monitoring IC can be normally detected.

Electrical configuration diagram explaining the first embodiment Electrical configuration diagram explaining the first embodiment Part 1 of a time chart explaining switch switching control details regarding the first embodiment Part 2 of the time chart explaining the switch switching control contents regarding the first embodiment Explanatory diagram of a comparative example of the first embodiment Part 1 of an electrical configuration diagram explaining the second embodiment Part 2 of the electrical configuration diagram explaining the second embodiment Part 1 of a time chart explaining switch switching details regarding the second embodiment Part 2 of a time chart explaining switch switching details regarding the second embodiment Part 3 of the time chart explaining the switch switching contents regarding the second embodiment Electrical configuration diagram explaining the third embodiment Electrical configuration diagram explaining the fourth embodiment Electrical configuration diagram explaining the fifth embodiment

Hereinafter, some embodiments will be described with reference to the drawings. In each of the embodiments described below, components that perform the same or similar operations will be denoted by the same or similar reference numerals, and the description may be omitted if necessary.

(First embodiment)
A first embodiment will be described with reference to FIGS. 1 to 5. As shown in FIG. 1, the assembled battery 1 is configured by connecting a plurality of battery cells Ce1 and Ce2, which are secondary batteries, in series in multiple stages. The battery monitoring device 2 is a device that monitors the voltage of the assembled battery 1, and is divided into an internal circuit of a monitoring IC 3 and an external circuit 3a provided outside the monitoring IC 3.

The monitoring IC 3 is an integrated circuit device provided to monitor the voltages of the battery cells Ce1 and Ce2. The monitoring IC 3 includes a control circuit 4, an equalization circuit 5, a multiplexer 6, an input switch 7, an A/D conversion circuit 8, and a determination circuit 9 as a determination section.

Outside the monitoring IC 3, as an external circuit 3a, an RC filter 11, equalization circuits 101 and 102, a resistor Rs, a first shunt resistor Rs1, a second shunt resistor Rs2, and a control terminal of the equalizing switch Sp are driven. A gate resistor Rm is configured for this purpose. The resistance Rs is set to about several tens of Ω, and the first shunt resistance Rs1 and the second shunt resistance Rs2 are set to about several tens of mΩ. Furthermore, a Zener diode D is configured to protect the control terminal of the equalization switch Sp.

Note that in FIG. 1, reference numbers are given in consideration of convenience when explaining the characteristic parts of the present application, and the assembled battery 1 has odd numbered battery cells Ce1 and even numbered battery cells Ce2. They are labeled separately.

In addition, the shunt resistance directly connected to the first electrode K1 on the positive side of the odd-numbered battery cell Ce1 is described as a first shunt resistance Rs1, and the shunt resistance directly connected to the second electrode K2 on the negative side of the battery cell Ce1 is described as a first shunt resistance Rs1. The shunt resistor is defined as a second shunt resistor Rs2.

Furthermore, the shunt resistance directly connected to the positive side second electrode K2 of the even numbered battery cell Ce2 is described as a second shunt resistance Rs2, and the shunt resistance directly connected to the negative side first electrode K1 of the even numbered battery cell Ce2 is described as a second shunt resistance Rs2. The shunt resistor is designated as a first shunt resistor Rs1.

The first shunt resistor Rs1 directly connected to the negative side of the even-numbered battery cell Ce2 and the first shunt resistor Rs1 directly connected to the positive side of the odd-numbered battery cell Ce1 are shared. Similarly, the second shunt resistor Rs2 directly connected to the negative side of the odd-numbered battery cell Ce1 and the second shunt resistor Rs2 directly connected to the positive side of the even-numbered battery cell Ce2 are shared.

A detection circuit for interelectrode voltage Vcl is provided corresponding to each battery cell Ce1, Ce2. A detection circuit for the inter-electrode voltage Vcl of the even-numbered battery cell Ce2 includes a first shunt resistor Rs1, a second shunt resistor Rs2, and a resistor Rs. The detection circuit for the interelectrode voltage Vcl of the adjacent odd-numbered battery cell Ce1 is also configured using a first shunt resistor Rs1, a second shunt resistor Rs2, and a resistor Rs, and these resistors Rs1, Rs2, and Rs are shared. are doing.

The monitoring IC 3 includes shunt resistance connection terminals Ts connected to both electrodes of each of the battery cells Ce1 and Ce2 through respective resistances Rs. The shunt resistance connection terminal Ts is connected to both electrodes K1 and K2 of the corresponding battery cells Ce1 and Ce2 via the discharge resistance Rs and the first shunt resistance Rs1 or the second shunt resistance Rs2, respectively.

The monitoring IC 3 includes filter connection terminals Tf connected from both electrodes K1 and K2 of each battery cell Ce1 and Ce2 through an RC filter 11, respectively. The interelectrode voltage Vcl of each battery cell Ce1 and Ce2 is directly input to the filter connection terminal Tf through the resistor Rf of the RC filter 11.

The RC filter 11 includes a resistor Rf and a capacitor Cf. The resistance Rf is a first node N1 between the first electrode K1 of the battery cell Ce and the first shunt resistor Rs1, and a second node N2 between the second electrode K2 of the battery cell Ce and the second shunt resistor Rs2. connected between.

Capacitor Cf is connected between filter connection terminal Tf and negative node N2 of battery cell Ce1. Since the RC filter 11 is directly connected to both electrodes of the battery cells Ce1 and Ce2, it is possible to detect the voltage between the nodes N1 and N2 of both electrodes while removing noise.

The equalization circuits 101 and 102 are each composed of an equalization switch Sp and a resistor Rp connected in series with the equalization switch Sp. The equalization switch Sp is constituted by a transistor, for example, an N-channel MOSFET.

The drain and source of the MOSFET constituting the equalization switch Sp and the resistor Rp are connected in series between a node between the first shunt resistor Rs1 and the resistor Rs and a node between the second shunt resistor Rs2 and the resistor Rs. When the equalization switch Sp is turned on, the equalization circuits 101 and 102 can equalize the voltages of the respective battery cells Ce1 and Ce2 by passing a circulating current through the battery cells Ce1 and Ce2.

An equalization circuit 5 is also provided inside the monitoring IC 3. The equalization circuit 5 includes transistors connected in series between two adjacent shunt resistance connection terminals Ts. The transistor is, for example, an N-channel MOSFET. The equalization circuit 5 is provided to equalize the voltages of the battery cells Ce1 and Ce2.

The multiplexer 6 includes odd numbered switches S1, S3, S5, S7... for selecting the voltage of each shunt resistance connection terminal Ts, even numbered switches S2, S4, for selecting the voltage of each filter connection terminal Tf, It is composed of S6, S8, and so on.

By controlling the multiplexer 6 to switch, the control circuit 4 can detect the voltage between the shunt resistance connection terminal Ts and the filter connection terminal Tf, thereby detecting the output voltage of the RC filter 11 corresponding to each battery cell Ce1, Ce2. can.

An input switch 7 is configured after the multiplexer 6. The input switch 7 is composed of a plurality of switches SI1 to SI4. The control circuit 4 can convert the output voltage between positive and negative by controlling the switches SI1 to SI4 of the input switch 7 on and off.

Although not shown, a level shift circuit is provided on the input side of the A/D conversion circuit 8, and the A/D conversion circuit 8 inputs voltage via the level shift circuit. The A/D conversion circuit 8 A/D converts the input voltage and outputs it to the determination circuit 9. The determination circuit 9 detects an abnormality in the equalization circuits 101 and 102.

Regarding the above configuration, a short circuit abnormality testing method for the equalization circuit 102 will be explained. In the following explanation, as shown in FIG. 2, a method for inspecting a short-circuit abnormality in the equalization switch Sp corresponding to the battery cell Ce2 will be explained. Hereinafter, the battery cell Ce2 will be referred to as the N+1st battery cell Ce2, and the battery cells Ce1 vertically adjacent to this battery cell Ce2 will be referred to as the Nth and N+2nd battery cells Ce1, respectively.

When detecting a short-circuit abnormality in the equalization circuit 102, the control circuit 4 turns on the switches S1 to S4 of the multiplexer 6, as shown in FIG. 3, with all equalization switches Sa and Sp kept off. - At the same time as off-controlling, switches SI1 to SI4 of the input switch 7 are on-off controlled.

If the equalization switch Sp corresponding to the N+1st battery cell Ce2 is stuck on and a short circuit abnormality occurs, the second shunt resistor Rs2, the equalization circuit 102, and the first shunt are removed from the N+1st battery cell Ce2. A short circuit current flows through the circuit path A (see FIG. 2) through the resistor Rs1. When the short circuit current flows through the circuit path A, a voltage is applied to the second shunt resistor Rs2, and a voltage is also applied to the first shunt resistor Rs1.

The control circuit 4 turns on the switches S1, S4, SI1, and SI4 and turns off the switches S2, S3, SI2, and SI3 during the first period T1 shown in FIG.

Then, the determination circuit 9 directly detects the interelectrode voltage Vcl_N+2 of the N+2-th battery cell Ce1 through a path that deviates from the circulating path A, here, a path to which the resistor Rf of the RC filter 11 is connected in the first period T1. Therefore, the first detected value can be obtained so as not to include the voltage drop ΔV of the second shunt resistor Rs2.

The control circuit 4 turns on the switches S2, S3, SI2, and SI3 and turns off the switches S1, S4, SI1, and SI4 during the second period T2.

Then, the determination circuit 9 detects the inter-electrode voltage Vcl_N+2 of the N+2 battery cell Ce1 via the second shunt resistor Rs2 in the second period T2, and sets the second shunt resistor Rs2 to the inter-electrode voltage Vcl_N+2 of the battery cell Ce1. The voltage Vcl_N+2+ΔV which is the sum of the voltages ΔV across both ends is detected. Thereby, the determination circuit 9 can acquire the second detected value so as to include the voltage drop ΔV of the second shunt resistor Rs2.

Thereafter, the determination circuit 9 determines whether or not a short-circuit abnormality has occurred in the equalization circuit 102 by comparing the results of the detection values in the two paths. For example, the determination circuit 9 subtracts the voltage Vcl_N+2 detected in the first period T1 from the voltage Vcl_N+2+ΔV detected in the second period T2, and on condition that the difference value between them reaches a predetermined value, the equalization circuit 102 subtracts the voltage Vcl_N+2 detected in the first period T1. It can be determined that a short circuit abnormality has occurred.

Although the determination circuit 9 determines whether the equalization circuit 102 is short-circuited by subtracting two detected values, the determination circuit 9 is not limited to the subtracted value. As long as a detected value based on the voltage drop ΔV can be obtained, the detected voltage in the first period T1 and the detected voltage in the second period T2 may be calculated in any manner. Considering that the interelectrode voltage Vcl of battery cells Ce1 and Ce2 varies based on various influences, a short circuit is detected based on the difference value obtained by subtracting one from the other with respect to the interelectrode voltage Vcl_N+2 of the same cell Ce1. It is desirable to determine whether or not an abnormality is occurring.

In order to detect a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1st battery cell Ce2 to be inspected, switches S1, S2, S3 corresponding to the N+2nd battery cell Ce1 adjacent to the positive side of the battery cell Ce2 are installed. , S4 have been shown to be on/off controlled, but the present invention is not limited to this.

In order to detect a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1-th battery cell Ce2, switches S5, S6, S7, and S8 corresponding to the N-th battery cell Ce1 adjacent to the negative side of the battery cell Ce2 are shown in FIG. 4, the determination circuit 9 may detect a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1-th battery cell Ce2 based on the detected voltages.

In this case, if the equalization switch Sp is short-circuited, the voltage drop ΔV occurring in the first shunt resistor Rs1 can be detected, and the short-circuit abnormality of the switch Sp of the equalization circuit 102 can be detected as described above.

FIG. 5 shows the configuration of a comparative example. The configuration of FIG. 5 shows a configuration in which the first shunt resistor Rs1 and the second shunt resistor Rs2 are not provided. Even if the inter-electrode voltage Vcl of the adjacent battery cell Ce1 is detected while applying the configuration of this comparative example, the voltage drop ΔV based on the first shunt resistance Rs1 and the second shunt resistance Rs2 cannot be detected. Therefore, a voltage change due to a short-circuit abnormality in the equalizing switch Sp cannot be detected, and as a result, a short-circuit abnormality in the equalizing switch Sp cannot be detected.

On the other hand, according to this embodiment, the first shunt resistor Rs1 and the second shunt resistor Rs2 are provided. The determination circuit 9 determines a first detected value that does not include the voltage drop ΔV that occurs across the second shunt resistor Rs2 and a second detected value that includes the voltage drop ΔV that occurs across the second shunt resistor Rs2 when the equalization switch Sp is turned off. It is determined whether or not a short-circuit abnormality has occurred in the equalization circuit 102 by comparing . As a result, a short-circuit abnormality in the equalization circuit 102 can be normally detected.

Further, when the determination circuit 9 obtains the first detection value in the first period T1, it directly detects the potential from the electrode K2 of the battery cell Ce1 through a route other than the circular route A, here, the RC filter 11. Thereby, the first detected value can be obtained so as not to include the voltage drop ΔV occurring across the second shunt resistor Rs2.

Further, when the determination circuit 9 obtains the second detected value in the second period T2, the interelectrode voltage of the N+2-th or N-th second battery cell Ce1 is determined via the second shunt resistor Rs2 or the first shunt resistor Rs1. Detecting Vcl. Therefore, the second detected value can be obtained so as to include the voltage drop ΔV occurring across the second shunt resistor Rs2.

The RC filter 11 has a first node N1 between the first electrode K1 and the first shunt resistor Rs1 of the battery cell Ce2, and a second node between the second electrode K2 and the second shunt resistor Rs2 of the battery cell Ce2. A series circuit including a resistor Rf and a capacitor Cf is connected between the resistor Rf and the capacitor Cf. Thereby, the inter-electrode voltage Vcl of each battery cell Ce1, Ce2 can be detected while suppressing the noise generated in the electrodes K1, K2 of each battery cell Ce1, Ce2, and it can be determined with high accuracy whether or not a short-circuit abnormality has occurred.

(Second embodiment)
A second embodiment will be described with reference to FIGS. 6 to 10. In the second embodiment, a configuration in which a π-type filter 211 is provided in place of the RC filter 11 will be described.

The monitoring IC 3 of this embodiment includes an input switch 7 consisting of switches SI1 to SI8 connected in the illustrated form. The control circuit 4 can convert the output voltage between positive and negative by controlling the switches SI1 to SI8 of the input switch 7 on and off. By connecting the switches S1 to S8... and the switches SI1 to SI8 between the multiplexer 6 and the input switch 7 as shown in FIG. The voltage between the filter connection terminals Tf can be detected.

As shown in FIG. 7, the π-type filter 211 connects a first node N1 between the first electrode K1 of the battery cell Ce2 and the first shunt resistor Rs1, and a second node N1 between the second electrode K2 and the second shunt resistor Rs2 of the battery cell Ce2. Two resistors Rf and a capacitor Cf are connected in a π-shape between the second node N2 and the second node N2.

When the equalization switch Sp corresponding to the N+1st battery cell Ce2 is stuck on and a short circuit occurs, the voltage from the N+1st battery cell Ce2 to the second shunt resistor Rs2, the resistor Rp of the equalization circuit 102, and the equalization switch Sp , and the circuit path A through the first shunt resistor Rs1. When the short circuit current flows through the circuit path A, a voltage is applied to the second shunt resistor Rs2, and a voltage is also applied to the first shunt resistor Rs1.

As shown in FIG. 8, the control circuit 4 turns on the switches S2, S4, SI2, and SI8 during the first period T1, and turns off the switches S1, S3, SI1, and SI7.

Then, the determination circuit 9 can detect the voltage between adjacent filter connection terminals Tf during the first period T1. The determination circuit 9 directly detects the inter-electrode voltage Vcl_N+2 of the N+2-th battery cell Ce1 through a path deviated from the circulating path A, here the RC filter 11, during the first period T1. Therefore, the first detected value can be obtained so as not to include the voltage drop ΔV of the second shunt resistor Rs2.

The control circuit 4 turns on the switches S1, S3, SI1, and SI4 and turns off the switches S2, S4, SI2, and SI3 during the second period T2. Then, the determination circuit 9 can detect the voltage between adjacent shunt resistance connection terminals Ts.

The determination circuit 9 detects the inter-electrode voltage Vcl of the N+2 battery cell Ce1 via the second shunt resistor Rs2 in the second period T2, and sets the inter-electrode voltage Vcl_N+2 of the second battery cell Ce1 to the second shunt resistor. A voltage Vcl_N+2+ΔV which is the sum of the voltage ΔV applied to Rs2 is detected. Thereby, the determination circuit 9 can acquire the second detected value so as to include the voltage drop ΔV of the second shunt resistor Rs2.

Thereafter, the determination circuit 9 determines whether or not a short-circuit abnormality has occurred in the equalization circuit 102 by comparing the results of the detection values in the two paths. For example, the determination circuit 9 subtracts the voltage Vcl_N+2 detected in the first period T1 from the voltage Vcl_N+2+ΔV detected in the second period T2, and, on the condition that the difference value between them has reached a predetermined value, the equalization circuit It is determined that a short circuit abnormality has occurred in 102.

As explained in the above embodiment, in order to detect a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1st battery cell Ce2, a switch corresponding to the Nth battery cell Ce1 adjacent to the negative side of the battery cell Ce2 is connected. S5, S6, S7, and S8 may be controlled on and off as shown in FIG. The determination circuit 9 detects a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1-th battery cell Ce2 based on the voltage detected through the input switch 7.

In this case, a voltage drop ΔV can be detected in the first shunt resistor Rs1 corresponding to the N+1-th battery cell Ce2, and a short-circuit abnormality in the equalization switch Sp of the equalization circuit 102 can be detected as described above.

Furthermore, in the configuration of the present embodiment, in order to detect a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1st battery cell Ce2 to be inspected, the switches S3, S4, S5, corresponding to the N+1st battery cell Ce2, S6 may be controlled on and off as shown in FIG. It is also possible for the determination circuit 9 to detect a short-circuit abnormality in the equalization switch Sp corresponding to the N+1-th battery cell Ce2 based on the voltage detected through the input switch 7.

When the control circuit 4 turns on the switches S3, S5, SI5, and SI3 during the second period T2 to detect the voltage between the adjacent shunt resistor connection terminals Ts, the first shunt resistor Rs1 and the second shunt resistor The interelectrode voltage Vcl_N+1 of the N+1-th battery cell Ce2 can be detected through Rs2. Then, if a short-circuit abnormality occurs in the equalization circuit 102, a double voltage drop of 2×ΔV can be detected as a differential voltage, as shown in FIG. Therefore, this embodiment also provides the same effects as those of the above-mentioned embodiment.

(Third embodiment)
A third embodiment will be described with reference to FIG. 11. In the third embodiment, as shown in FIG. 11, a ground filter 311 is provided in place of the RC filter 11. The ground filter 311 corresponding to the N+2 battery cell Ce1 has a circuit including a resistor Rf and a capacitor Cf connected in series between the node between the first electrode K1 and the first shunt resistor Rs1 of the battery cell Ce1 and the ground node. Connected. The ground filter 311 corresponding to the N+1st battery cell Ce2 has a circuit including a resistor Rf and a capacitor Cf connected in series between the node between the second electrode K2 and the second shunt resistor Rs1 of the battery cell Ce2 and the ground node. Connected.

In the third embodiment, by performing the same control as in the second embodiment, the determination circuit 9 detects a short-circuit abnormality in the equalization circuit 102 corresponding to the N+1st battery cell Ce2, as shown in the voltage value in FIG. This embodiment can provide the same effects as the second embodiment.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. 12. FIG. 12 is a configuration example shown in place of FIG. 2. As shown in FIG. 12, the equalization switch Spa may be configured using a P-channel MOSFET instead of the equalization switch Sp corresponding to the N+1-th battery cell Ce2. As shown in FIG. 12, a resistor Rsa is commonly connected between the gates and sources of the N-channel and P-channel MOSFETs. Since the resistance value of this resistor Rsa can be set to a large value and driven, the equalization switch Sp can be driven even if the voltage of the battery cells Ce1 and Ce2 becomes low.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIG. 13. In the embodiment described above, the determination circuit 9 is provided in the monitoring IC 3, but as shown in FIG. 13, the configuration and function of the determination circuit 9 may be configured in the microcomputer 20 connected to the monitoring IC 3. The function of the determination circuit 9 may be realized based on a program stored inside the microcomputer 20, or may be configured by a logic circuit that digitally processes the output value of the A/D conversion circuit 8.

(Other embodiments)
The present invention is not limited to the embodiments described above, and can be implemented with various modifications, and can be applied to various embodiments without departing from the gist thereof.

Moreover, the configurations of the embodiments described above may be combined or replaced. Although the present invention has been described based on the embodiments described above, it is understood that the present invention is not limited to the embodiments or structures. The present invention also includes various modifications and equivalent modifications. In addition, various combinations and configurations, as well as other combinations and configurations that include one, more, or fewer elements, fall within the scope and spirit of the present invention.

In the drawing, Ce1 and Ce2 are battery cells (Ce2 is a predetermined battery cell, Ce1 is a second battery cell), S is an abnormality determination device, 1 is an assembled battery, 2 is a battery monitoring device, 3 is a monitoring IC, and 102 is an equivalent 9 is a judgment circuit (judgment unit), 11 is an RC filter (filter), 211 is a π-type filter (filter), 311 is a ground filter (filter), Sp is an equalization switch, A is a circulation path, and Rs1 is a The first shunt resistance (shunt resistance) and Rs2 indicate the second shunt resistance (shunt resistance).

Claims (4)

An abnormality determination device for a battery monitoring device (2) that monitors an assembled battery (1) in which a plurality of battery cells (Ce1, Ce2) are connected in series,
a monitoring IC (3) that monitors the voltage of the plurality of battery cells (Ce1, Ce2);
It is configured using an equalization switch (Sp) provided outside the monitoring IC, and when the equalization switch is turned on, the plurality of an equalization circuit (102) that equalizes the voltages of the battery cells;
shunt resistors (Rs2, Rs1) configured to be interposed in the circular path;
a filter (11; 211; 311) configured to include a resistor (Rf) and a capacitor (Cf) and directly input the voltage between the electrodes of the battery cell;
When controlling the equalization switch to turn off, the first detected value obtained through the filter does not include a voltage drop that occurs in the shunt resistor due to the current flowing through the circuit path, and the current in the circuit path. a second detection value obtained to include the voltage drop that occurs in the shunt resistor due to the flow of the voltage, and a determination unit that determines whether or not a short circuit abnormality has occurred in the equalization circuit. (9) An abnormality determination device for a battery monitoring device, comprising: The shunt resistance includes a first shunt resistance (Rs1) connected to one first electrode (K1) of the battery cell, and a second shunt resistance connected to the other second electrode (K2) of the battery cell. A resistor (Rs2),
The filter (11) is
It is constituted by a series circuit including a resistor (Rf) and a capacitor (Cf), and includes a first node (N1) between the first electrode of the battery cell and the first shunt resistor, and a first node (N1) between the second electrode of the battery cell and the first shunt resistor. The abnormality determination device for a battery monitoring device according to claim 1, comprising an RC filter connected between the second node (N2) and the second shunt resistor. The shunt resistance includes a first shunt resistance (Rs1) connected to one first electrode (K1) of the battery cell, and a second shunt resistance connected to the other second electrode (K2) of the battery cell. A resistor (Rs2),
The filter (211) is
between a first node (N1) between the first electrode of the battery cell and the first shunt resistor and a second node (N2) between the second electrode of the battery cell and the second shunt resistor; 2. The abnormality determination device for a battery monitoring device according to claim 1, comprising a π-type filter in which two resistors (Rf) and a capacitor (Cf) are connected in a π-type. The shunt resistance includes a first shunt resistance (Rs1) connected to one first electrode (K1) of the battery cell, and a second shunt resistance connected to the other second electrode (K2) of the battery cell. A resistor (Rs2),
The filter (311) is
The battery monitor according to claim 1, comprising a ground filter (311) having a resistor and a capacitor connected in series between a first node between one first electrode of the battery cell and the shunt resistor and a ground node. Equipment abnormality determination device.

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