Patent Description:
Among them, the lithium batteries are in the limelight since they have almost no memory effect compared to nickel-based batteries and also have very low self-discharging rate and high energy density.

Meanwhile, in some cases, the secondary battery is used as a single secondary battery, but in many cases, a plurality of secondary batteries are connected in series and/or in parallel to provide a high-voltage and/or large-capacity energy storage system, and the plurality of secondary batteries are used in the form of a battery pack including a battery management system that controls the charging and discharging operation of the secondary batteries therein.

It is very important to maintain the insulation state of the energy storage system using the high-voltage, large-capacity secondary batteries. If the insulation state of the battery is not maintained, a leakage current may be generated to cause various problems. Specifically, due to the leakage current, not only the life of the battery may be shortened, but also a malfunction of electrical equipment connected to the battery may be caused and a safety accident such as an electric shock may occur.

To prevent the leakage current from being generated, it is required to monitor an insulation resistance of the battery.

Seeing Patent Literature <NUM>, a device for diagnosing an insulation resistance measurement circuit is disclosed, and a state of the insulation resistance measurement circuit is diagnosed while turning on or off a verification switch connected in series with a verification resistor. In particular, Patent Literature <NUM> discloses a configuration for diagnosing a state of the insulation resistance measurement circuit by comparing a measured voltage with a reference voltage while turning on or off a plurality of verification switches, respectively.

If the voltage is measured while respectively turning on or off a plurality of verification switches as described above, a verification switch must be provided to each of the plurality of verification resistors. In addition, since the plurality of verification switches are controlled one by one to a turn-on or turn-off state, a considerable amount of time is required to diagnose the state of the insulation resistance measurement circuit.

In particular, if only one of the plurality of verification switches is controlled to a turn-on state and the state of one corresponding insulation resistance is diagnosed, it is impossible to diagnose the state of the insulation resistance measurement circuit by comprehensively considering the states of all resistors included in the insulation resistance measurement circuit.

(Patent Literature <NUM>) <CIT>
Further background art is described in <CIT>, <CIT>, and <CIT>.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing an apparatus and method for diagnosing an insulation resistance measurement circuit, which may effectively diagnose various states of the insulation resistance measurement circuit based on a measured voltage value and an estimated voltage value of a battery module.

In one aspect, the present disclosure provides an apparatus for diagnosing an insulation resistance measurement circuit according to independent claim <NUM>, comprising: a measuring unit configured to measure a voltage of a battery module having at least one battery cell; a first diagnosing unit connected to a positive electrode terminal of the battery module and configured to include a plurality of first diagnosis resistors and a first switch; a second diagnosing unit connected to a negative electrode terminal of the battery module and configured to include a plurality of second diagnosis resistors, a second switch and a power supply unit; and a control unit configured to calculate an estimated voltage value of the battery module by using a first voltage value calculated based on a signal received from the first diagnosing unit and a second voltage value calculated based on a signal received from the second diagnosing unit, the apparatus for diagnosing an insulation resistance measurement circuit being characterized in that the control unit (<NUM>) is further configured to calculate a voltage ratio between the calculated estimated voltage value and the measured voltage value of the battery module measured by the measuring unit, and diagnose a state of the insulation resistance measurement circuit of the battery module according to a comparison result of the calculated voltage ratio and a reference ratio.

The plurality of first diagnosis resistors may be configured to include a first resistor, a second resistor and a third resistor connected in series between the positive electrode terminal of the battery module and the control unit; and a fourth resistor having one end connected to a node between the second resistor and the third resistor and the other end connected to a first ground.

The first switch may be configured to be connected in series between the first resistor and the second resistor.

The plurality of second diagnosis resistors may be configured to include a sixth resistor, a seventh resistor and an eighth resistor connected in series between the negative electrode terminal of the battery module and the control unit; and a ninth resistor having one end connected to a node between the seventh resistor and the eighth resistor and the other end connected to the power supply unit.

The second switch may be configured to be connected in series between the sixth resistor and the seventh resistor.

The power supply unit may be configured to have one end connected to the ninth resistor and the other end connected to the ground.

The first diagnosing unit may be configured to further include a first capacitor connected in series between the fourth resistor and the first ground.

The plurality of first diagnosis resistors may be configured to further include a fifth resistor connected in parallel to the first capacitor.

The plurality of second diagnosis resistors may be configured to further include a tenth resistor provided between the ninth resistor and the power supply unit and configured to have one end connected to the other end of the ninth resistor and the other end connected to the power supply unit.

The second diagnosing unit may be configured to further include a second capacitor having one end connected to a node between the ninth resistor and the tenth resistor and the other end connected to a second ground.

The control unit may be configured to estimate a positive electrode voltage value of the battery module based on the first voltage value, a resistance of the plurality of first diagnosis resistors and a resistance of the first switch, estimate a negative electrode voltage value of the battery module based on a voltage value supplied from the power supply unit, the second voltage value, a resistance of the plurality of second diagnosis resistors and a resistance of the second switch, and calculate the estimated voltage value by adding the estimated positive electrode voltage value and the estimated negative electrode voltage value.

The voltage ratio may be a ratio of the estimated voltage value to the measured voltage value and may be calculated using a following equation.

Here, ROV is the voltage ratio, Bv is the measured voltage value of the battery module measured by the measuring unit, Vp is the estimated positive electrode voltage value, and Vn is the estimated negative electrode voltage value.

The control unit may be configured to set the reference ratio as a predetermined ratio range in advance, diagnose the state of the insulation resistance measurement circuit as a failure state when the voltage ratio does not belong to the predetermined ratio range, and output a diagnostic trouble code corresponding to the failure state.

The measuring unit may be configured to measure a temperature of the battery module.

The control unit may be configured to change the predetermined ratio range based on the temperature of the battery module measured by the measuring unit.

The control unit may be configured to increase the size of the predetermined ratio range when the measured temperature of the battery module is higher than an upper temperature limit, and decrease the size of the predetermined ratio range when the measured temperature of the battery module is lower than a lower temperature limit.

The control unit may be configured to estimate a state of charge (SOC) of the battery module and change the predetermined ratio range based on the estimated SOC.

After outputting the diagnostic trouble code, the control unit may be configured to send a turn-off command to a main switch provided on a charging and discharging path of the battery module to block the connection of the battery module.

After outputting the diagnostic trouble code to the outside, the control unit may be configured to send the turn-off command to the main switch only when receiving a main switch turn-off command from the outside.

In another aspect, the present disclosure may provide a battery pack, comprising the apparatus for diagnosing an insulation resistance measurement circuit according to an aspect of the present disclosure.

In still another aspect and as set out in independent claim <NUM>, the present disclosure provides a method for diagnosing an insulation resistance measurement circuit using the apparatus for diagnosing an insulation resistance measurement circuit, comprising: a voltage measuring step of measuring a voltage of a battery module having at least one battery cell; an estimated voltage value calculating step of calculating an estimated voltage value by using a first voltage value calculated based on a signal received from a first diagnosing unit and a second voltage value calculated based on a signal received from a second diagnosing unit; the method being characterized in that it further comprises a voltage ratio calculating step of calculating a voltage ratio between the calculated estimated voltage value and the measured voltage value of the battery module measured in the voltage measuring step; and a state diagnosing step of diagnosing a state of the insulation resistance measurement circuit of the battery module according to a comparison result of the calculated voltage ratio calculated in the voltage ratio calculating step and a reference ratio.

According to an aspect of the present disclosure, since the state of the insulation resistance measurement circuit may be diagnosed based on the signal from which the noise component is removed, there is an advantage that the state of the insulation resistance measurement circuit may be more accurately diagnosed.

In addition, according to an aspect of the present disclosure, when diagnosing the state of the insulation resistance measurement circuit, since the voltage ratio based on the measured voltage value of the battery module and the estimated voltage value is used, there is an advantage that the state of the insulation resistance measurement circuit may be diagnosed more diversely and accurately.

In addition, according to an aspect of the present disclosure, since the reference ratio compared to the voltage ratio may be changed according to the state of the battery module, there is an advantage that the state of the insulation resistance measurement circuit may be diagnosed by reflecting the state of the battery module.

The effects of the present disclosure are not limited to the above, and other effects not mentioned herein will be clearly understood by those skilled in the art from the appended claims.

Furthermore, the term "control unit" described in the specification refers to a unit that processes at least one function or operation, and may be implemented by hardware, software, or a combination of hardware and software.

Hereinafter, a preferred embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

<FIG> is a diagram exemplarily showing a configuration of a battery pack <NUM> including an apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to an embodiment of the present disclosure.

Referring to <FIG>, the battery pack <NUM> may include a battery module <NUM> and an apparatus <NUM> for diagnosing an insulation resistance measurement circuit. In addition, the battery module <NUM> and the apparatus <NUM> for diagnosing an insulation resistance measurement circuit may be connected to each other inside the battery pack <NUM>.

The battery module <NUM> may include at least one battery cell. For example, if a plurality of battery cells are included in the battery module <NUM>, the plurality of battery cells may be connected to each other in series and/or in parallel.

<FIG> is a diagram schematically showing the battery pack <NUM> including the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG>, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit may include a measuring unit <NUM>, a first diagnosing unit <NUM>, a second diagnosing unit <NUM>, and a control unit <NUM>. The measuring unit <NUM>, the first diagnosing unit <NUM>, the second diagnosing unit <NUM>, and the control unit <NUM> may be connected to each other in a wired and/or wireless manner.

Meanwhile, referring to <FIG>, it may be regarded that insulation resistances Rleak(+), Rleak(-) are provided between both terminals of the battery module <NUM> and the ground (for example, the chassis of a vehicle). In other words, the insulation resistances Rleak(+), Rleak(-) may be regarded as virtual resistor components corresponding to the insulation state of the battery module <NUM>.

Specifically, a first insulation resistance Rleak(+) may be connected to a positive electrode terminal (+) of the battery module <NUM>, and a second insulation resistance Rleak(-) may be connected to a negative electrode terminal (-) of the battery module <NUM>. If the insulation state of the positive electrode terminal of the battery module <NUM> is well maintained, the insulation resistance Rleak(+), Rleak(-) will have a sufficiently large resistance. Conversely, if the insulation state of the battery module <NUM> is destroyed, the insulation resistances Rleak(+), Rleak(-) will have a very small resistance below an allowable value. The insulation resistances Rleak(+), Rleak(-) are measured through an insulation resistance measurement circuit, and based on the measured results, it may be determined whether the insulation resistances Rleak(+), Rleak(-) are destroyed.

In the present disclosure, the insulation resistance measurement circuit may include a first diagnosing unit <NUM> and a second diagnosing unit <NUM>. Specifically, the first diagnosing unit <NUM> is a circuit for measuring the first insulation resistance Rleak(+), and the second diagnosing unit <NUM> is a circuit for measuring the second insulation resistance Rleak(-).

Therefore, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit may diagnose the state of the insulation resistance measurement circuit by diagnosing the state of the first diagnosing unit <NUM> and the second diagnosing unit <NUM>. Hereinafter, each component of the apparatus <NUM> for diagnosing an insulation resistance measurement circuit will be described in detail.

The measuring unit <NUM> may be configured to measure a voltage of the battery module <NUM> including at least one battery cell.

Preferably, the measuring unit <NUM> may measure the voltage of the battery module <NUM> by measuring voltages at both terminals of the battery module <NUM> and calculating a difference between the measured voltages at both terminals.

For example, in the embodiment of <FIG>, a first sensing line SL1 and a second sensing line SL2 may be connected to the measuring unit <NUM>. The measuring unit <NUM> may measure a voltage at the positive electrode terminal of the battery module <NUM> through the first sensing line SL1 and measure a voltage at the negative electrode terminal of the battery module <NUM> through the second sensing line SL2. That is, the measuring unit <NUM> may measure the voltages at both terminals of the battery module <NUM> through the first sensing line SL1 and the second sensing line SL2. In addition, the measuring unit <NUM> may measure the voltage of the battery module <NUM> based on a difference between the measured voltage at the positive electrode terminal and the measured voltage at the negative electrode terminal. In addition, if the battery module <NUM> includes a plurality of battery cells, the measuring unit <NUM> may measure the voltage of each battery cell included in the battery module <NUM>.

The first diagnosing unit <NUM> may be configured to be connected to the positive electrode terminal (+) of the battery module <NUM>.

Specifically, the first diagnosing unit <NUM> may be connected between the positive electrode terminal (+) of the battery module <NUM> and a positive electrode terminal (P+) of the battery pack <NUM>.

For example, seeing the embodiment of <FIG>, the first diagnosing unit <NUM> may be provided between the control unit <NUM> and a first node N1 between the positive electrode terminal (+) of the battery module <NUM> and the positive electrode terminal (P+) of the battery pack <NUM>. In addition, the first diagnosing unit <NUM> may be connected to the first node N1 and the control unit <NUM>.

In addition, the first diagnosing unit <NUM> may be configured to include a plurality of first diagnosis resistors.

Preferably, the first diagnosing unit <NUM> may include a plurality of diagnosis resistors for measuring the first insulation resistance Rleak(+). For example, as shown in <FIG>, the plurality of first diagnosis resistors may include a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

The second diagnosing unit <NUM> may be configured to be connected to the negative electrode terminal (-) of the battery module <NUM>.

Specifically, the second diagnosing unit <NUM> may be connected between the negative electrode terminal (-) of the battery module <NUM> and the negative electrode terminal (P-) of the battery pack <NUM>.

For example, seeing the embodiment of <FIG>, the second diagnosing unit <NUM> may be provided between the control unit <NUM> and a third node N3 between the negative electrode terminal (-) of the battery module <NUM> and the negative electrode terminal (P-) of the battery pack <NUM>. In addition, the second diagnosing unit <NUM> may be connected to the third node N3 and the control unit <NUM>.

In addition, the second diagnosing unit <NUM> may be configured to include a plurality of second diagnosis resistors and a power supply unit DC.

Preferably, the second diagnosing unit <NUM> may include a plurality of second diagnosis resistors for measuring the second insulation resistance Rleak(-) and a power supply unit DC. For example, as shown in <FIG>, the plurality of second diagnosis resistors may include a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9.

Meanwhile, the power supply unit DC included in the second diagnosing unit <NUM> may be a unit that supplies power separately from the battery module <NUM>. The power supply unit DC may supply a preset DC power such that the voltage value calculated by the control unit <NUM> is positive through the second diagnosing unit <NUM>. For example, the power supply unit DC may supply 5V DC power.

The control unit <NUM> may be configured to calculate an estimated voltage value of the battery module <NUM> by using a first voltage value based on a signal received from the first diagnosing unit <NUM> and a second voltage value based on a signal received from the second diagnosing unit <NUM>.

Specifically, the control unit <NUM> may calculate the first voltage value based on a signal received through the first diagnosing unit <NUM>, and calculate the second voltage value based on a signal received through the second diagnosing unit <NUM>. Here, the control unit <NUM> may include an analog-digital converter ADC. The control unit <NUM> may convert an analog signal input through a first input terminal IN1 and a second input terminal IN2 into a digital signal through the ADC. In addition, the control unit <NUM> may calculate the first voltage value and the second voltage value based on the digital signal changed through the ADC included therein.

For example, referring to <FIG>, the control unit <NUM> may separately include a first input terminal IN1 for receiving a signal from the first diagnosing unit <NUM> and a second input terminal IN2 for receiving a signal from the second diagnosing unit <NUM>, separately. That is, because the control unit <NUM> includes the first input terminal IN1 and the second input terminal IN2 separately, it is possible to prevent an unexpected error by minimizing interference between the signal received from the first diagnosing unit <NUM> and the signal received from the second diagnosing unit <NUM>. Therefore, the control unit <NUM> may measure the first voltage value and the second voltage value more accurately.

In addition, the control unit <NUM> may calculate the estimated voltage value of the battery module <NUM> based on the calculated first voltage value and the calculated second voltage value. Here, the estimated voltage value of the battery module <NUM> may be the voltage of the battery module <NUM> estimated by the control unit <NUM>. That is, the control unit <NUM> may estimate a difference in voltages at both terminals of the battery module <NUM> by using the first voltage value and the second voltage value.

Also, the control unit <NUM> may be configured to calculate a voltage ratio between the calculated estimated voltage value and the measured voltage value of the battery module <NUM> measured by the measuring unit <NUM>.

The control unit <NUM> may receive the measured voltage value of the battery module <NUM> measured by the measuring unit <NUM>, apart from receiving the analog signals from the first diagnosing unit <NUM> and the second diagnosing unit <NUM>. Here, the measured voltage value may be the voltage of the battery module <NUM> measured by the measuring unit <NUM> through the first sensing line SL1 and the second sensing line SL2. That is, the measured voltage value may be a difference between the voltages at both terminals of the battery module <NUM> measured by the measuring unit <NUM>. In addition, the control unit <NUM> may calculate a ratio between the measured voltage value directly measured by the measuring unit <NUM> and the estimated voltage value based on the calculated voltage value.

For example, the control unit <NUM> may calculate the voltage ratio by calculating the ratio of the estimated voltage value to the measured voltage value.

In addition, the control unit <NUM> may be configured to diagnose a state of the insulation resistance measurement circuit according to the comparison result of the calculated voltage ratio and a reference ratio.

Preferably, the reference ratio may be set in advance. Here, the reference ratio is a ratio at which the state of the insulation resistance measurement circuit may be determined as a normal state. For example, the reference ratio may be preset by the control unit <NUM> or may be preset and input to the control unit.

The control unit <NUM> may determine whether the state of the insulation resistance measurement circuit is a normal state by comparing the calculated voltage ratio with the reference ratio.

For example, if a plurality of resistors and switches provided to the insulation resistance measurement circuit are in a normal state, the voltage ratio calculated by the control unit <NUM> may be a value close to the reference ratio. Alternatively, if the reference ratio is set as a ratio range, the voltage ratio calculated by the control unit <NUM> may be included in the reference ratio. In this case, the control unit <NUM> may determine the first voltage value and the second voltage value as voltage values that may be received when the insulation resistance measurement circuit is in a normal state. In addition, the control unit <NUM> may diagnose the state of the insulation resistance measurement circuit as a normal state.

Conversely, if the difference between the voltage ratio calculated by the control unit <NUM> and the reference ratio is large, the control unit <NUM> may diagnose that the insulation resistance measurement circuit is not in a normal state.

The apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure does not diagnose the state of the insulation resistance measurement circuit using only the estimated voltage value, but may diagnose the condition of the insulation resistance measurement circuit based on the voltage ratio between the estimated voltage value and the measured voltage value. Therefore, the state of the insulation resistance measurement circuit may be accurately diagnosed when the resistors included therein are not only in an open circuit state but also in a short circuit state.

Here, the control unit <NUM> provided to the apparatus <NUM> for diagnosing an insulation resistance measurement circuit may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, and a data processing device, and the like, known in the art to execute various control logics performed in the present disclosure. In addition, when the control logic is implemented in software, the control unit <NUM> may be implemented as a set of program modules. At this time, the program module may be stored in a memory and executed by the processor. The memory may be provided in or out of the processor, and may be connected to the processor by various well-known means.

Also, referring to <FIG> and <FIG>, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to an embodiment of the present disclosure may further include a storage unit <NUM>. The storage unit <NUM> may store programs and data necessary for the control unit <NUM> to diagnose the insulation resistance measurement circuit. That is, the storage unit <NUM> may store data and program required for each component of the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to an embodiment of the present disclosure to perform operations and functions, or data generated in the process of performing operations and functions. The storage unit <NUM> is not specially limited in its kind as long as it is an information storage means known in the art as being capable of recording, erasing, updating and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, and the like. In addition, the storage unit <NUM> may store program codes in which processes executable by the control unit <NUM> are defined.

Referring to <FIG>, the plurality of first diagnosis resistors may include a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4. Here, the first resistor R1, the second resistor R2 and the fourth resistor R4 may be distribution resistors to reduce the amount of current input to the first input terminal IN1 of the control unit <NUM>, and the third resistor R3 may be a current limiting resistor to reduce the amount of current input to the first input terminal IN1 of the control unit <NUM> via the second node N2.

Specifically, the plurality of first diagnosis resistors may include a first resistor R1, a second resistor R2 and a third resistor R3 connected in series between the positive electrode terminal (+) of the battery module <NUM> and the control unit <NUM>. In addition, the plurality of first diagnosis resistors may include a fourth resistor R4 having one end connected to a node between the second resistor R2 and the third resistor R3 and the other end connected to a first ground G1.

For example, referring to <FIG>, one end of the first resistor R1 may be connected to the first node N1 between the positive electrode terminal (+) of the battery module <NUM> and the positive electrode terminal (P+) of the battery pack <NUM>. That is, the first diagnosing unit <NUM> may be connected in parallel to a main charging and discharging path of the battery module <NUM>. Here, the main charging and discharging path may be a high current path to which the positive electrode terminal (P+) of the battery pack <NUM>, the battery module <NUM>, and the negative electrode terminal (P-) of the battery pack <NUM> are connected.

In addition, one end of the second resistor R2 may be connected to the other end of the first resistor R1, one end of the third resistor R3 may be connected to the other end of the second resistor R2, and the other end of the third resistor R3 may be connected to the first input terminal IN1 of the control unit <NUM>. Accordingly, the control unit <NUM> may receive the first voltage value dropped by the first diagnosing unit <NUM> through the first input terminal IN1.

In addition, a first switch S1 is a switching element that turns on/off the connection state of the first diagnosing unit <NUM>, and may be configured to be connected in series between the first resistor R1 and the second resistor R2. The control unit <NUM> may send a control command to the first switch S1 to control the operation state of the first switch S1 to a turn-on state or a turn-off state.

Further, referring to <FIG>, the plurality of second diagnosis resistors may include a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. Here, the sixth resistor R6, the seventh resistor R7 and the ninth resistor R9 are distribution resistors to reduce the amount of current input to the second input terminal IN2 of the control unit <NUM>. Also, the ninth resistor R9 may be a pull-up resistor. The eighth resistor R8 may be a current limiting resistor to reduce the amount of current input to the second input terminal IN2 of the control unit <NUM> via a fourth node N4.

Specifically, the plurality of second diagnosis resistors may include a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8 connected in series between the negative electrode terminal (-) of the battery module <NUM> and the control unit <NUM>. In addition, the plurality of second diagnosis resistors may include a ninth resistor R9 having one end connected to the fourth node N4 between the seventh resistor R7 and the eighth resistor R8 and the other end connected to the power supply unit DC.

For example, referring to <FIG>, one end of the sixth resistor R6 may be connected to a third node N3 between the negative electrode terminal (-) of the battery module <NUM> and the negative electrode terminal (P-) of the battery pack <NUM>. That is, the second diagnosing unit <NUM> may be connected in parallel to the main charging and discharging path of the battery module <NUM>.

In addition, one end of the seventh resistor R7 may be connected to the other end of the sixth resistor R6, one end of the eighth resistor R8 may be connected to the other end of the seventh resistor R7, and the other end of the eighth resistor R8 may be connected to the second input terminal IN2 of the control unit <NUM>. Accordingly, the control unit <NUM> may receive the second voltage value dropped by the second diagnosing unit <NUM> through the second input terminal IN2.

In addition, the second switch S2 is a switching element that turns on/off the connection state of the second diagnosing unit <NUM>, and may be configured to be connected in series between the sixth resistor R6 and the seventh resistor R7. The control unit <NUM> may send a control command to the second switch S2 to control the operation state of the second switch S2 to a turn-on state or a turn-off state.

Also, the power supply unit DC may be configured such that its one end is connected to the ninth resistor R9 and the other end is connected to the ground. The power supply unit DC is an element that applies a DC power, and may apply, for example, 5V DC power to the second diagnosing unit <NUM>. Therefore, the second voltage value calculated at the second input terminal IN2 of the control unit <NUM> may be calculated as a positive number.

The apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may calculate the estimated voltage value through the calculated first voltage value and the calculated second voltage value. Accordingly, there is an advantage in that the accuracy of calculating the estimated voltage value is improved, and the insulation resistance measurement circuit may be diagnosed more accurately based on the estimated voltage value.

<FIG> is a diagram schematically showing a battery pack <NUM> including an apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to another embodiment of the present disclosure.

The first diagnosing unit <NUM> may further include a first capacitor C1 connected in series between the fourth resistor R4 and the first ground G1. Here, the first capacitor C1 is a bypass filter for removing noise, and may remove noise included in a signal flowing to the first input terminal IN1 of the control unit <NUM> through the first diagnosing unit <NUM>. That is, the noise passing through the first capacitor C1 may flow to the first ground G1.

For example, referring to <FIG>, one end of the first capacitor C1 may be connected to the other end of the fourth resistor R4, and the other end may be connected to the first ground G1. In addition, the plurality of first diagnosis resistors may further include a fifth resistor R5 connected in parallel to the first capacitor C1. One end of the fifth resistor R5 may be connected between the other end of the fourth resistor R4 and one end of the first capacitor C1, and the other end thereof may be connected to the first ground G1. Preferably, the first capacitor C1 may constitute a low pass filter. That is, the first capacitor C1 may filter high-frequency components included in the current flowing to the first input terminal IN1 of the control unit <NUM> through the first diagnosing unit <NUM> so that the control unit <NUM> may receive a signal from which noise is removed.

In addition, the plurality of second diagnosis resistors may further include a tenth resistor R10 provided between the ninth resistor R9 and the power supply unit DC. That is, the plurality of second diagnosis resistors may further include a tenth resistor R10 having one end connected to the other end of the ninth resistor R9 and the other end connected to the power supply unit DC. Here, the tenth resistor R10 may be a pull-up resistor.

The second diagnosing unit <NUM> may further include a second capacitor C2 having one end connected to a node between the ninth resistor R9 and the tenth resistor R10 and the other end connected to the second ground G2. Like the first capacitor C1, the second capacitor C2 may be a bypass filter for removing noise.

For example, referring to <FIG>, the second capacitor C2 may remove noise included in a signal flowing to the second input terminal IN2 of the control unit <NUM> through the second diagnosing unit <NUM>. That is, the noise passing through the second capacitor C2 may flow to the second ground G2.

Since the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may further include the first capacitor C1 and the second capacitor C2, it is possible to remove a noise component from a signal received from the control unit <NUM>. Therefore, since the noise component is removed from the estimated voltage value calculated by the control unit <NUM>, the state of the insulation resistance measurement circuit may be diagnosed more accurately.

The control unit <NUM> may be configured to estimate a positive electrode voltage value of the battery module <NUM> based on the first voltage value, the resistance of the plurality of first diagnosis resistors, and the resistance of the first switch S1.

Preferably, the resistances of the plurality of first diagnosis resistors and the first switch S1 may be stored in the storage unit <NUM> in advance. In addition, the control unit <NUM> may estimate the positive electrode voltage value of the battery module <NUM> by referring to the resistances of the first switch S1 and the plurality of first diagnosis resistors stored in the storage unit <NUM>.

For example, the control unit <NUM> may estimate the positive electrode voltage value of the battery module <NUM> using Equation <NUM> below.

Here, Vp is the estimated positive electrode voltage value, R1, R2, R4 and R5 are the resistances of the first resistor R1, the second resistor R2, the fourth resistor R4 and the fifth resistor R5, respectively, RS1 is the resistance of the first switch S1, and V1 is the first voltage value calculated by the control unit <NUM> based on the signal input to the first input terminal IN1.

That is, the control unit <NUM> may estimate the positive electrode voltage value of the battery module <NUM> using the calculated first voltage value and the resistances of the first resistor R1, the second resistor R2, the fourth resistor R4, the fifth resistor R5 and the first switch S1 stored in the storage unit <NUM>. Preferably, the positive electrode voltage value (Vp) estimated using Equation <NUM> may be a positive electrode voltage value estimated based on a voltage distribution resistance of the first diagnosing unit <NUM>.

In addition, the control unit <NUM> may be configured to estimate a negative electrode voltage value of the battery module <NUM> based on the voltage value supplied from the power supply unit DC, the second voltage value, the resistance of the plurality of second diagnosis resistors and the resistance of the second switch S2.

Preferably, the voltage value supplied from the power supply unit DC may be set in advance, and the set voltage value may be stored in the storage unit <NUM>. In addition, the resistance of the plurality of second diagnosis resistors and the resistance of the second switch S2 may be stored in the storage unit <NUM> in advance. The control unit <NUM> may estimate the negative electrode voltage value of the battery module <NUM> by referring to the voltage value supplied from the power supply unit DC, the resistance of the plurality of second diagnosis resistors and the resistance of the second switch S2, which are stored in the storage unit <NUM>.

For example, the control unit <NUM> may estimate the negative electrode voltage value of the battery module <NUM> using Equation <NUM> below.

Here, Vn is the estimated negative electrode voltage value, R6, R7, R9 and R10 are the resistances of the sixth resistor R6, the seventh resistor R7, the ninth resistor R9 and the tenth resistor R10 included in the plurality of second diagnosis resistors, respectively, RS2 is the resistance of the second switch S2, VDC is the voltage value supplied from the power supply unit DC, and V2 is the second voltage value calculated by the control unit <NUM> based on the signal input to the second input terminal IN2.

That is, the control unit <NUM> may estimate the negative electrode voltage value of the battery module <NUM> by using the calculated second voltage value, the resistances of the sixth resistor R6, the seventh resistor R7, the ninth resistor R9, the tenth resistor R10 and the second switch S2 stored in the storage unit <NUM>, and the voltage value supplied from the power supply unit DC. Preferably, the negative electrode voltage value (Vn) estimated using Equation <NUM> may be a negative electrode voltage value estimated based on a voltage distribution resistance of the second diagnosing unit <NUM>.

Also, the control unit <NUM> may be configured to calculate the estimated voltage value by adding the estimated positive electrode voltage value (Vp) and the estimated negative electrode voltage value (Vn).

In addition, the control unit <NUM> may diagnose the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> by using the calculated estimated voltage value and the measured voltage value measured by the measuring unit <NUM>.

The apparatus <NUM> for diagnosing an insulation resistance measurement circuit does not diagnose the state of the insulation resistance measurement circuit using only the measured voltage value or the estimated voltage value, but may diagnose the state of the insulation resistance measurement circuit using both the measured voltage value and the estimated voltage value. Therefore, the state of the insulation resistance measurement circuit may be diagnosed more accurately.

The voltage ratio is a ratio of the estimated voltage value to the measured voltage value, and may be calculated using Equation <NUM> below.

Here, ROV is the voltage ratio, Bv is the measured voltage value of the battery module <NUM> measured by the measuring unit <NUM>, Vp is the positive electrode voltage value estimated using Equation <NUM>, and Vn is the negative electrode voltage value estimated using Equation <NUM>.

That is, the voltage ratio (ROV) may be a ratio of the estimated voltage value (Vp+Vn) to the measured voltage value (Bv) of the battery module <NUM>. Specifically, the voltage ratio (ROV) may be a ratio of the estimated voltage value estimated based on the voltage distribution resistance of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> to the measured voltage value (Bv) of the battery module <NUM>.

Meanwhile, the positive electrode voltage value (Vp) estimated using Equation <NUM> and the negative electrode voltage value (Vn) estimated using Equation <NUM> do not mean the positive electrode voltage and the negative electrode voltage of the battery module <NUM>, respectively. That is, the difference between the estimated positive electrode voltage value (Vp) and the estimated negative electrode voltage value (Vn) does not refer to a potential difference between the voltages at both terminals of the battery module <NUM>, but the sum of the estimated positive electrode voltage value (Vp) and the estimated negative electrode voltage value (Vn) is the potential difference between the voltages at both terminals of the battery module <NUM>.

The control unit <NUM> may diagnose the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> using the voltage ratio calculated using Equation <NUM>.

That is, the control unit <NUM> may diagnose the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> using the ratio of the estimated voltage value and the measured voltage value, rather than diagnosing using only the estimated voltage value. Therefore, there is an advantage in that the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> may be accurately diagnosed when at least one of the plurality of resistors included in the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is not only in an open circuit state but also in a short circuit state.

Hereinafter, a limitation in diagnosing the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> using only whether the first voltage value and the second voltage value are calculated will be described with reference to <FIG>.

<FIG> is a diagram schematically showing a first operation state of the battery pack <NUM> including the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to another embodiment of the present disclosure.

Specifically, <FIG> is a diagram schematically showing an operation state in which the insulation resistance measurement circuit is diagnosed. That is, in the first operation state, the control unit <NUM> sends a turn-on command to the first switch S1, the second switch S2 and the main switch S0 to control the first switch S1, the second switch S2 and the main switch S0 to a turn-on state.

The control unit <NUM> may calculate the first voltage value based on the signal input through the first input terminal IN1, and calculate the second voltage value based on the signal input through the second input terminal IN2.

For example, it is assumed that the resistance of the first resistor R1 is <NUM> [GΩ], which is the case where the first resistor R1 is in an open circuit state. In this case, the control unit <NUM> may calculate the first voltage value as a value close to <NUM>. In this case, since the calculated first voltage value is close to <NUM>, the control unit <NUM> may diagnose that at least one of the plurality of first diagnosis resistors provided in the first diagnosing unit <NUM> is in an open circuit state.

As another example, it is assumed that the resistance of the first resistor R1 is <NUM> [Ω], which is the case where the first resistor R1 is in a short circuit state. In this case, the first voltage value and the second voltage value may be different from the voltage value when the state of the first resistor R1 is a normal state. The first voltage value and the second voltage value may be larger or smaller than the voltage value when the state of the first resistor R1 is the normal state. In other words, from the point of view of the overall circuit, the battery module <NUM>, the first diagnosing unit <NUM>, the second diagnosing unit <NUM> and the control unit <NUM> form one path, so if the state of a resistor provided in the first diagnosing unit <NUM> is a failure state, not only the first voltage value but also the second voltage value may be affected therefrom.

In this case, since both the first voltage value and the second voltage value are calculated as a value greater than <NUM>, the control unit <NUM> may determine the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> as a normal state. That is, the control unit <NUM> may not diagnose that at least one of the plurality of resistors provided in the first diagnosing unit <NUM> and/or the second diagnosing unit <NUM> is in a short circuit state by using only whether the first voltage value and the second voltage value are calculated.

Meanwhile, since the control unit <NUM> according to the present disclosure calculates the voltage ratio between the measured voltage value and the estimated voltage value, if the voltage ratio calculated when the first resistor R1 is in a short circuit state is different from the reference ratio, the insulation resistance measurement circuit may be diagnosed as being not in a normal state.

Therefore, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may accurately diagnose whether the insulation resistance measurement circuit is in a failure state, even when at least one of the plurality of resistors belonging to the insulation resistance measurement circuit is in a short circuit state.

The control unit <NUM> may be configured to set the reference ratio as a predetermined ratio range in advance.

If the control unit <NUM> calculates the voltage ratio using Equation <NUM>, the reference ratio may be set based on <NUM>. For example, the reference ratio may be set in advance as a ratio range of <NUM> to <NUM>. More preferably, the reference ratio may be set in advance as a ratio range of <NUM> to <NUM>. The set reference ratio may be stored in the storage unit <NUM>.

That is, when the control unit <NUM> diagnoses the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> using the calculated voltage ratio, the reference ratio may be set as a predetermined ratio range in advance in consideration of an error during the voltage ratio calculating process.

The control unit <NUM> may be configured to diagnose the state of the insulation resistance measurement circuit as a failure state if the calculated voltage ratio does not belong to the predetermined ratio range. Conversely, if the calculated voltage ratio belongs to the predetermined ratio range, the control unit <NUM> may diagnose the state of the insulation resistance measurement circuit as a normal state.

In addition, if the state of the insulation resistance measurement circuit is determined as a failure state, the control unit <NUM> may be configured to output a diagnostic trouble code (DTC) corresponding to the failure state.

For example, if the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure is provided to a vehicle, the control unit <NUM> may output the diagnostic trouble code corresponding to the failure state to an on-board diagnostics (OBD) of a vehicle, a display panel, or an external server for checking a condition of the vehicle. In this case, a user may check that the insulation resistance measurement circuit is in a failure state and perform vehicle inspection to prevent an accident caused by a failure of the insulation resistance measurement circuit.

Hereinafter, in the embodiment of <FIG>, the operation of the control unit <NUM> according to the state of the first resistor R1 when the states of resistors other than the first resistor R1 are all normal states will be described.

For convenience of explanation, it is assumed that the voltage of the battery module <NUM> is <NUM> [V] and the predetermined ratio range is set as <NUM> to <NUM> in advance. That is, it is assumed that the reference ratio is set in advance as the range of <NUM> to <NUM>.

If the first resistor R1 is in a normal state, the positive electrode voltage value (Vp) calculated using Equation <NUM> may be <NUM> [V], and the negative electrode voltage value (Vn) calculated using Equation <NUM> may be <NUM> [V]. That is, the estimated voltage value (Vp+Vn) may be <NUM> [V].

In this case, since the voltage ratio calculated using Equation <NUM> is <NUM>, the calculated voltage ratio may belong to the predetermined ratio range.

Therefore, since the calculated voltage ratio of the control unit <NUM> belongs to the predetermined ratio range, both the first diagnosing unit <NUM> and the second diagnosing unit <NUM> may be diagnosed as being in a normal state.

If the first resistor R1 is in an open circuit state, it is assumed that the resistance of the first resistor R1 is <NUM> [GΩ]. In this case, due to the influence of the power supply unit DC connected to the control unit <NUM>, the first voltage value (V1) may be calculated as a value close to about <NUM> [V]. Also, the second voltage value (V2) may be calculated as a value close to about <NUM> [V] due to the influence of the power supply unit DC.

For example, the control unit <NUM> may calculate the positive electrode voltage value (Vp) as <NUM> [V] using Equation <NUM>, and calculate the negative electrode voltage value (Vn) as <NUM> [V] using Equation <NUM>. That is, the estimated voltage value (Vp+Vn) may be <NUM> [V].

In this case, since the voltage ratio calculated using Equation <NUM> is <NUM>, the calculated voltage ratio may not belong to the predetermined ratio range.

Since the calculated voltage ratio does not belong to the predetermined ratio range, the control unit <NUM> may diagnose that at least one of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is in a failure state. In particular, since the first voltage value (V1) is calculated as a value close to <NUM> [V], the control unit <NUM> may diagnose the state of the first diagnosing unit <NUM> as a failure state. Preferably, the control unit <NUM> may diagnose that the first diagnosing unit <NUM> is in an open circuit state.

If the first resistor R1 is in a short circuit state, it is assumed that the resistance of the first resistor R1 is <NUM> [Ω]. Therefore, the first voltage value (V1) and the second voltage value (V2) calculated in this case may be different from the first voltage value (V1) and the second voltage value (V2) when the first resistor R1 is in a normal state.

For example, the positive electrode voltage value (Vp) calculated using Equation <NUM> may be <NUM> [V], and the negative electrode voltage value (Vn) calculated using Equation <NUM> may be <NUM> [V]. That is, the estimated voltage value (Vp+Vn) may be <NUM> [V].

Since the calculated voltage ratio does not belong to the predetermined ratio range, the control unit <NUM> may diagnose that at least one of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is in a failure state. In particular, since the first voltage value (V1), the second voltage value (V2), the positive electrode voltage value (Vp) and the negative electrode voltage value (Vn) are not all close to <NUM>, the control unit <NUM> may diagnose that at least one of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is in a failure state. Preferably, the control unit <NUM> may diagnose that at least one of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is in a short circuit state.

As described above, if the control unit <NUM> diagnoses that the first diagnosing unit <NUM> and/or the second diagnosing unit <NUM> is in a failure state, the control unit <NUM> outputs a diagnostic trouble code corresponding to the failure state to inform the failure state of the insulation resistance measurement circuit to the outside.

That is, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure has an advantage of more flexibly and reasonably diagnosing the state of the insulation resistance measurement circuit by setting the reference ratio in consideration of an error during the voltage ratio calculation process.

In addition, if the insulation resistance measurement circuit is diagnosed as being in a failure state, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may prevent an additional accident caused by the insulation resistance measurement circuit in a failure state in advance by outputting the diagnostic trouble code.

Measuring unit <NUM> may be configured to measure a temperature of the battery module <NUM>.

Preferably, the measuring unit <NUM> may include a temperature sensor to measure the temperature as well as the voltage of the battery module <NUM>.

In the embodiment of <FIG> and <FIG>, the measuring unit <NUM> may measure the temperature of the battery module <NUM> through a third sensing line SL3.

The control unit <NUM> may be configured to change the predetermined ratio range based on the temperature of the battery module <NUM> measured by the measuring unit <NUM>. Preferably, the control unit <NUM> may change the size of the predetermined ratio range based on the measured temperature of the battery module <NUM>.

For example, the storage unit <NUM> may store a temperature-ratio lookup table indicating a correspondence relationship between the temperature of the battery module <NUM> and the predetermined ratio range. The control unit <NUM> may change the predetermined ratio range to a ratio range corresponding to the temperature of battery module <NUM> measured by the measuring unit <NUM> by referring to the temperature-ratio lookup table stored in the storage unit <NUM>.

As another example, a reference temperature corresponding to the predetermined ratio range may be set in advance. The control unit <NUM> may compare the temperature of the battery module <NUM> measured by the measuring unit <NUM> with the reference temperature, and change the predetermined ratio range as much as a difference between the measured temperature of the battery module <NUM> and the reference temperature.

If the temperature of the battery module <NUM> rises so that the temperature of the battery pack <NUM> including the battery module <NUM> and the apparatus <NUM> for diagnosing an insulation resistance measurement circuit rises, elements of the insulation resistance measurement circuit may be affected therefrom. For example, since the resistors and the switches provided in the insulation resistance measurement circuit are physical elements, the physical properties of the elements may be affected by the temperature of the battery module <NUM>. Therefore, the control unit <NUM> may minimize the influence of the temperature of the battery module <NUM> on the physical elements such as resistors and switches by changing the predetermined ratio range based on the temperature of the battery module <NUM>.

That is, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure has an advantage of more accurately diagnosing the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> by changing the predetermined ratio range according to the temperature of the battery module <NUM>.

The control unit <NUM> may be configured to increase the size of the predetermined ratio range if the measured temperature of the battery module <NUM> is higher than an upper temperature limit. In addition, the control unit <NUM> may be configured to reduce the size of the predetermined ratio range if the measured temperature of the battery module <NUM> is lower than a lower temperature limit.

For example, if an ambient temperature rises, the resistance of a resistor element may increase since its resistor coefficient increases. If the resistance of the plurality of first diagnosis resistors included in the first diagnosing unit <NUM> increases, the first voltage value (V1) and second voltage value (V2) calculated by the control unit <NUM> may become smaller compared to the case where the temperature of the battery module <NUM> is the reference temperature. This is because the resistor coefficient of each of the plurality of first diagnosis resistors increases and thus the resistance of the plurality of first diagnosis resistors increases.

As a result, since the estimated voltage value becomes smaller, even if the plurality of first diagnosis resistors are in a normal state, the voltage ratio calculated by the control unit <NUM> may become smaller compared to the case where the temperature of the battery module <NUM> is the reference temperature.

That is, since the resistor coefficient is related to the ambient temperature, the control unit <NUM> may increase the size of the predetermined ratio range as the temperature of the battery module <NUM> rises, in order to compensate for the influence of the temperature of the battery module <NUM> on the surrounding.

Hereinafter, the effect of the temperature of the battery module <NUM> on the diagnosis of the insulation resistance measurement circuit will be described based on an example.

For example, it is assumed that the predetermined ratio range is set as <NUM> to <NUM>, and the estimated voltage value is <NUM> [V] and the measured voltage value is <NUM> [V] when the temperature of the battery module <NUM> is <NUM>. That is, when the temperature of the battery module <NUM> is <NUM>, the voltage ratio calculated by the control unit <NUM> is <NUM>.

After that, if the voltage of the battery module <NUM> is maintained constantly and the temperature rises to <NUM>, the states of the plurality of resistors included in the first diagnosing unit <NUM> and the second diagnosing unit <NUM> are a normal state, but the resistance may be increased for all of them. Therefore, the first voltage value and the second voltage value may be decreased compared to the case where the temperature of the battery module <NUM> is <NUM>.

That is, seeing Equations <NUM> and <NUM>, since the first voltage value (V1) and the second voltage value (V2) are values calculated by the control unit <NUM>, they may decrease as the temperature of the battery module <NUM> rises. However, other values are not measured values but are preset values to estimate the positive electrode voltage value (Vp) and the negative electrode voltage value (Vn), and thus may always be constant regardless of a current temperature of the battery module <NUM>. Therefore, if the temperature of the battery module <NUM> rises to <NUM>, the estimated positive electrode voltage value (Vp) and the estimated negative electrode voltage value (Vn) inevitably decrease.

Seeing Equation <NUM>, when the temperature of the battery module <NUM> is <NUM>, the positive electrode voltage value (Vp) and the negative electrode voltage value (Vn) decrease, so the sum of them, namely the estimated voltage value (Vp+Vn), is also inevitably small. In addition, even though the measured voltage value (Bv) is kept constantly when the temperature of the battery module <NUM> is <NUM> and <NUM>, the size of the estimated voltage value (Vp+Vn) decreases, so the calculated voltage ratio is inevitably lowered.

Therefore, the voltage ratio calculated as <NUM> when the temperature of the battery module <NUM> is <NUM> will be calculated as being less than <NUM> when the temperature of the battery module <NUM> is <NUM>, and since the predetermined ratio range is set as <NUM> to <NUM>, the control unit <NUM> may diagnose the state of the first diagnosing unit <NUM> and/or the second diagnosing unit <NUM> as a failure state.

As described above, even in a situation in which any one of the plurality of resistors belonging to the first diagnosing unit <NUM> and the second diagnosing unit <NUM> has no failure, the state of the insulation resistance measurement circuit may be incorrectly diagnosed because the temperature of the battery module <NUM> rises.

Meanwhile, according to the present disclosure, when the temperature of the battery module <NUM> rises, the size of the predetermined ratio range may also increase correspondingly. Therefore, even if the voltage ratio is calculated to be less than <NUM>, the control unit <NUM> may diagnose the state of the first diagnosing unit <NUM> and/or the second diagnosing unit <NUM> as a normal state.

Therefore, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure has an advantage of more accurately diagnosing the state of the insulation resistance measurement circuit by changing the predetermined ratio range in consideration of the temperature of the battery module <NUM>.

In addition, the control unit <NUM> may be configured to estimate a state of charge (SOC) of the battery module <NUM>.

Specifically, the storage unit <NUM> may further store a voltage-SOC lookup table to which voltage and SOC of the battery module <NUM> are mapped. Here, the voltage-SOC lookup table may be a table configured to indicate a correspondence relationship between voltage and SOC of the battery module <NUM>. In general, since voltage and SOC of the battery module <NUM> are in a one-to-one relationship with each other, the control unit <NUM> may estimate the SOC of the battery module <NUM> by referring to the voltage-SOC lookup table stored in the storage unit <NUM>.

For example, the control unit <NUM> may receive voltage information of the battery module <NUM> from the measuring unit <NUM> through the third input terminal IN3. In addition, the control unit <NUM> may select an SOC corresponding to the received voltage information by referring to the voltage-SOC lookup table stored in the storage unit <NUM>. The control unit <NUM> may estimate the selected SOC as an SOC of the battery module <NUM>.

In addition, the control unit <NUM> may be configured to change the predetermined ratio range based on the estimated SOC.

Specifically, if the SOC of the battery module <NUM> is lowered below a predetermined lower limit, the battery pack <NUM> including the battery module <NUM> having at least one battery cell may reduce the amount of discharge current to prevent overdischarge of the battery module <NUM>. That is, if the SOC of the battery module <NUM> is lowered below the predetermined lower limit, a discharge C-rate may be reduced.

If the discharge C-rate is decreased, the amount of current output from the battery module <NUM> decreases, so the first voltage value and the second voltage value calculated by the control unit <NUM> may also be decreased. The change in the first voltage value and the second voltage value may affect the estimated voltage value, and the change in the estimated voltage value may affect the diagnosis on the state of the insulation resistance measurement circuit. Therefore, if the SOC of the battery module <NUM> is estimated to be less than the predetermined lower limit, the control unit <NUM> may change the size of the predetermined ratio range to improve the accuracy of diagnosis on the state of the insulation resistance measurement circuit.

Preferably, if the SOC of the battery module <NUM> is estimated to be less than the predetermined lower limit, the control unit <NUM> may increase the size of the predetermined ratio range to minimize the influence of the change of the discharge C-rate on the diagnosis on the state of the insulation resistance measurement circuit.

Therefore, since the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure diagnoses the state of the insulation resistance measurement circuit in consideration of the SOC of the battery module <NUM>, the accuracy of the state diagnosis may be improved.

Meanwhile, the storage unit <NUM> may further store a voltage-temperature-SOC lookup table to which voltage, temperature and SOC of the battery module <NUM> are mapped. That is, the voltage-temperature-SOC lookup table may store a SOC corresponding to voltage and temperature of the battery module <NUM>.

The control unit <NUM> may estimate the SOC of the battery module <NUM> corresponding to the temperature and voltage information of the battery module <NUM> received from the measuring unit <NUM> by referring to the voltage-temperature-SOC lookup table stored in the storage unit <NUM>. In this case, since the SOC of battery module <NUM> may be estimated in consideration of temperature as well as voltage, the accuracy of estimation on the SOC of the battery module <NUM> may be improved.

In addition, since the predetermined ratio range is changed based on the SOC of the battery module <NUM>, the accuracy and reliability of diagnosis on the state of the insulation resistance measurement circuit may be further improved. Also, since the apparatus <NUM> for diagnosing an insulation resistance measurement circuit outputs the diagnostic trouble code to take an appropriate diagnostic measure with improved accuracy, it is possible to further improve the safety of the battery pack <NUM>.

After outputting the diagnostic trouble code, the control unit <NUM> may be configured to block the connection of the battery module <NUM> by sending a turn-off command to the main switch S0 provided on a charging and discharging path of the battery module <NUM>.

<FIG> is a diagram schematically showing a second operation state of the battery pack <NUM> including the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to another embodiment of the present disclosure.

Referring to <FIG>, after outputting the diagnostic trouble code, the control unit <NUM> may send a turn-off command to the main switch S0 to control the operation state of the main switch S0 to a turn-off state. That is, the second operation state is a state in which the control unit <NUM> sends a turn-off command to the main switch S0 and the main switch S0 is controlled to a turn-off state.

Therefore, if at least one of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> is diagnosed as being in a failure state, the operation of the battery pack <NUM> may be stopped as a diagnostic measure by the control unit <NUM>. In other words, since the control unit <NUM> takes this diagnostic measure after outputting the diagnostic trouble code, the operation of the battery pack <NUM> including the insulation resistance measurement circuit in a failure state is stopped, thereby preventing accidents related to abnormal insulation of the battery module <NUM> in advance.

The apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure has an advantage of preventing unexpected accidents in advance by taking an immediate measure by the control unit <NUM>.

Meanwhile, after outputting the diagnostic trouble code to the outside, the control unit <NUM> may be configured to send a turn-off command to the main switch S0 only when receiving a main switch S0 turn-off command from the outside.

For example, it is assumed that the battery pack <NUM> including the apparatus <NUM> for diagnosing an insulation resistance measurement circuit is provided to a vehicle and the vehicle is running. In this case, in order to prevent the operation of the battery pack <NUM> from being interrupted, the control unit <NUM> may output the diagnostic trouble code and then send a turn-off command to the main switch S0 only when receiving the main switch S0 turn-off command from the outside.

That is, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure has an advantage of stopping the operation of the battery pack <NUM> more safely by taking an appropriate measure to the insulation resistance measurement circuit according to an external command. In addition, according to this measure, since the operation of the battery pack <NUM> is stopped, an accident caused by the battery pack <NUM> in which the insulation resistance measurement circuit is in a failure state may be prevented in advance.

The apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may be applied to a battery management system (BMS). That is, the BMS according to the present disclosure may include the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure described above. In this configuration, at least some components of the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may be implemented by supplementing or adding functions of components included in the conventional BMS. For example, the measuring unit <NUM>, the control unit <NUM> and the storage unit <NUM> of the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may be implemented as components of the BMS.

In addition, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure may be provided to the battery pack <NUM>. That is, the battery pack <NUM> according to the present disclosure may include the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to the present disclosure described above. Here, the battery pack <NUM> may include at least one battery cell, the apparatus <NUM> for diagnosing an insulation resistance measurement circuit, electrical equipment (such as a BMS, a relay, a fuse, or the like), and a case.

<FIG> is a diagram schematically showing a method for diagnosing an insulation resistance measurement circuit according to another embodiment of the present disclosure. Here, the method for diagnosing an insulation resistance measurement circuit may be performed at each component of the apparatus <NUM> for diagnosing an insulation resistance measurement circuit according to an embodiment of the present disclosure.

Referring to <FIG>, the method for diagnosing an insulation resistance measurement circuit may include a voltage measuring step (S100), an estimated voltage value calculating step (S200), a voltage ratio calculating step (S300), and a state diagnosing step (S400).

The voltage measuring step (S100) is a step of measuring the voltage of the battery module <NUM> having at least one battery cell, and may be performed by the measuring unit <NUM>.

For example, referring to <FIG> and <FIG>, the measuring unit <NUM> may measure the positive electrode voltage of the battery module <NUM> through the first sensing line SL1 and measure the negative electrode voltage of the battery module <NUM> through the second sensing line SL2.

In addition, the measuring unit <NUM> may measure the voltage of the battery module <NUM> by obtaining a difference between the positive electrode voltage and the negative electrode voltage. Also, the measuring unit <NUM> may transmit the measured voltage of the battery module <NUM> to the third input terminal IN3 of the control unit <NUM>.

The estimated voltage value calculating step (S200) is a step of calculating the estimated voltage value by using the first voltage value calculated based on the signal received from the first diagnosing unit <NUM> and the second voltage value calculated based on the signal received from the second diagnosing unit <NUM>, and may be performed by the control unit <NUM>.

In the embodiment of <FIG> and <FIG>, the control unit <NUM> may calculate the first voltage value of the battery module <NUM> based on the signal input to the first input terminal IN1 through the first diagnosing unit <NUM>. Similarly, the control unit <NUM> may calculate the second voltage value of the battery module <NUM> based on the signal input to the second input terminal IN2 through the second diagnosing unit <NUM>.

The control unit <NUM> may estimate the positive electrode voltage value of the battery module <NUM> based on the first voltage value using Equation <NUM>. Also, the control unit <NUM> may estimate the negative electrode voltage value of the battery module <NUM> based on the second voltage value using Equation <NUM>.

Finally, the control unit <NUM> may calculate the estimated voltage value of the battery module <NUM> by adding the estimated positive electrode voltage value and the estimated negative electrode voltage value.

The voltage ratio calculating step (S300) is a step of calculating a voltage ratio between the estimated voltage value and the measured voltage value of the battery module <NUM> measured in the voltage measuring step (S100), and may be performed by the control unit <NUM>.

The control unit <NUM> may calculate the voltage ratio by putting the positive electrode voltage value and the negative electrode voltage value of the battery module <NUM> calculated in the estimated voltage value calculating step (S200) and the measured voltage value of the battery module <NUM> measured by the measuring unit <NUM> in the voltage measuring step (S100) to Equation <NUM>.

That is, the control unit <NUM> may calculate the ratio of the estimated voltage value to the measured voltage value of the battery module <NUM> by using Equation <NUM>.

The state diagnosing step (S400) is a step of diagnosing the state of the insulation resistance measurement circuit according to the comparison result of the voltage ratio calculated in the voltage ratio calculating step (S300) and the reference ratio, and may be performed by the control unit <NUM>.

The control unit <NUM> may diagnose the state of the insulation resistance measurement circuit, namely the first diagnosing unit <NUM> and the second diagnosing unit <NUM>, by comparing the preset reference ratio with the voltage ratio calculated in the voltage ratio calculating step (S300).

For example, if the reference ratio is set as a predetermined ratio range, the control unit <NUM> may diagnose the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> according to whether the calculated voltage ratio belongs to the predetermined ratio range.

Preferably, the control unit <NUM> may change the size of the predetermined ratio range in consideration of the state of the battery module <NUM>.

For example, the control unit <NUM> may change the size of the predetermined ratio range in consideration of at least one of the temperature and SOC of the battery module <NUM>. In this case, since the state of the battery module <NUM> is considered, there is an advantage that the states of the first diagnosing unit <NUM> and the second diagnosing unit <NUM> may be diagnosed more accurately by the control unit <NUM>.

Claim 1:
An apparatus (<NUM>) for diagnosing an insulation resistance measurement circuit, comprising:
a measuring unit (<NUM>) configured to measure a voltage of a battery module (<NUM>) having at least one battery cell;
a first diagnosing unit (<NUM>) connected to a positive electrode terminal (+) of the battery module and including a plurality of first diagnosis resistors (R1-R4) and a first switch (S1);
a second diagnosing unit (<NUM>) connected to a negative electrode terminal (-) of the battery module and including a plurality of second diagnosis resistors (R6-R9), a second switch (S2) and a power supply unit (DC); and
a control unit (<NUM>) configured to calculate an estimated voltage value of the battery module by using a first voltage value calculated based on a signal received from the first diagnosing unit and a second voltage value calculated based on a signal received from the second diagnosing unit,
the apparatus (<NUM>) for diagnosing an insulation resistance measurement circuit being characterized in that the control unit (<NUM>) is further configured to calculate a voltage ratio between the calculated estimated voltage value and the measured voltage value of the battery module measured by the measuring unit, and diagnose a state of the insulation resistance measurement circuit of the battery module according to a comparison result of the calculated voltage ratio and a reference ratio.