Battery pack voltage measuring circuit

Abstract

The invention provides a battery pack voltage measuring circuit. The battery pack voltage measuring circuit includes: a relay section for controlling battery pack voltage measurement; a first branch part and a second branch part which are provided between the battery pack voltage input terminal and the relay part, branch the battery pack voltage into different paths according to the battery pack voltage, and then supply the battery pack voltage to the relay part; and a voltage distribution unit that divides the battery pack voltage supplied through the first branch unit or the second branch unit and the relay unit, and outputs the divided battery pack voltage to an output terminal.

Description

Technical Field

[0001] The present invention relates to a battery pack voltage measurement circuit, and more particularly to a battery pack voltage measurement circuit for measuring a battery pack voltage and outputting a result value. Background Art

[0002] Secondary cells that can be charged and discharged, that is, batteries, are widely used as energy sources for mobile devices such as smartphones. In addition, batteries are also used as energy sources for environmentally friendly vehicles such as electric vehicles and hybrid electric vehicles, which are proposed as a solution to air pollution caused by gasoline vehicles and diesel vehicles using fossil fuels. The types of applications using batteries are becoming very diverse, and it is expected that in the future, batteries will be applied to more fields and products than now.

[0003] Such batteries are generally used in the form of a battery pack rather than as a single battery cell. A battery pack includes at least one battery module, and a battery module may include a plurality of battery cells. In addition, battery packs with high capacity and high voltage specifications are being developed to be used for a longer time and driven more powerfully according to consumer demand.

[0004] The high voltage specification of the battery pack provides more powerful driving power to power consuming devices (such as electric vehicles) using the battery pack. However, due to the different internal characteristics and internal resistance of the battery cells constituting the battery pack, voltage deviations may occur between the battery cells as the high-voltage battery is continuously charged and discharged. When the voltage deviations between the battery cells accumulate, the battery cells may be overcharged or over-discharged, and thus cause fatal damage to the high-voltage battery. In addition, when the life of the battery cells constituting the battery pack is shortened or their performance is reduced, the performance of the battery pack may deteriorate. Therefore, in order to monitor and manage the performance of the battery pack, it is necessary to accurately measure the voltage of the battery pack, which determines the performance of the battery pack. To this end, the battery pack includes a battery pack voltage measurement circuit.

[0005] The battery pack voltage measurement circuit includes a relay switch and an analog-to-digital conversion (ADC) output circuit. Here, the relay switch performs an on / off operation based on an overcurrent, and the ADC output circuit measures the voltage of the battery pack according to the current flowing through the relay switch.

[0006] In addition, the voltage of the battery pack used in electric vehicles tends to increase from 400V to 800V. Therefore, the battery pack voltage measurement circuit should also be appropriately designed for the increased voltage of the battery pack. To this end, the relay switch in the battery pack voltage measurement circuit should meet the allowable voltage value of 800V. However, in the case where the relay switch operates stably at the allowable voltage of 800V, advanced process technology and high-quality materials should be used, so a very high-priced relay switch, that is, a high-specification relay switch, is required. When an existing low-specification relay switch with an allowable voltage value of 400V is used to measure the voltage of a battery pack of 800V, various problems may occur because the breakpoint of the relay switch may be delayed.

[0007] In order to use a low-specification relay switch, the battery pack voltage measurement circuit can be configured by connecting the low-specification relay switch and the relay resistor in parallel. That is, the battery pack voltage measurement circuit can be configured as follows: the first resistor, the relay circuit, the second resistor and the ADC output circuit are connected in series between the ground terminal and the power terminal of the battery pack, and the relay circuit is provided with a relay element and a relay resistor connected in parallel. This battery pack voltage measurement circuit has the advantage of being able to use a 400V rated relay switch even in an 800V battery pack by adding a relay resistor connected in parallel with the relay switch. However, there is a problem of generating leakage current through the relay resistor even after the relay switch is disconnected. In addition, since the first resistor and the second resistor are set to a resistance ratio of 800V, when measuring a battery pack voltage of 400V having a resistance ratio higher than it, the measurement accuracy is reduced.

[0008] The related prior art includes the following documents.

[0009] Korean Patent Registration No.10-2041869 Summary of the invention

[0010] Technical issues

[0011] The present invention provides a battery pack voltage measurement circuit capable of measuring a high voltage by using a low-specification relay switch.

[0012] The present invention provides a battery pack voltage measurement circuit which can prevent leakage current even when a low-specification relay switch is used.

[0013] Technical Solution

[0014] According to an example of the present invention, a battery pack voltage measurement circuit includes: a relay unit, which controls the battery pack voltage measurement; a first branch unit and a second branch unit, which are arranged between a battery pack voltage input terminal and the relay unit, and branch the battery pack voltage into different paths according to the battery pack voltage, and then supply the branched voltage to the relay unit; and a voltage distribution unit, which divides the battery pack voltage supplied through the first branch unit or the second branch unit and the relay unit, and outputs the divided battery pack voltage to an output terminal.

[0015] The first branch unit includes a first resistor and a first switch connected in series between the battery pack voltage input terminal and the relay unit.

[0016] The second branch unit includes a second resistor and a second switch, which are connected in series between the battery pack voltage input terminal and the relay unit and are connected in parallel with the first resistor and the first switch, respectively.

[0017] The relay unit includes a relay switch and a third resistor, and the relay switch and the third resistor are connected in parallel between a connection point between the first branch unit and the second branch unit and the voltage distribution unit.

[0018] The battery pack voltage measurement circuit further includes a control unit for controlling the first switch, the second switch, and the relay switch.

[0019] The control unit selectively opens and closes the first switch and the second switch according to the magnitude of the battery pack voltage.

[0020] A first resistance ratio which is a ratio between the sum of the resistances of the voltage distribution unit and the first resistance and a second resistance ratio which is a ratio between the sum of the resistances of the voltage distribution unit and the second resistance are set to be different from each other.

[0021] According to another example of the present invention, a battery pack voltage measurement circuit includes: a first branch unit, which is arranged between a battery pack voltage input terminal and a first node to branch out a first battery pack voltage; a second branch unit, which is arranged between the battery pack voltage input terminal and the first node and is connected in parallel with the first branch unit to branch out a second battery pack voltage; a relay unit, which is arranged between the first node and the second node and controls the measurement of the battery pack voltage according to the switch operation; and a voltage distribution unit, which is arranged between the second node and the ground terminal and divides the battery pack voltage supplied through the first branch unit or the second branch unit and the relay unit, and then outputs the voltage to the output terminal.

[0022] The first branch unit includes a first resistor and a first switch connected in series between the battery pack voltage input terminal and the first node.

[0023] The second branch unit includes a second resistor and a second switch which are connected in series between the battery pack voltage input terminal and the first node and are connected in parallel with the first resistor and the first switch, respectively.

[0024] The relay unit includes a relay switch and a third resistor connected in parallel between the first node and the second node.

[0025] The battery pack voltage measurement circuit further includes a control unit for controlling the first switch, the second switch, and the relay switch.

[0026] The control unit selectively opens and closes the first switch and the second switch according to the magnitude of the battery pack voltage.

[0027] A resistance value of the first resistor and a resistance value of the second resistor are different from each other.

[0028] Beneficial Effects

[0029] Since a low-spec relay switch can be used, the battery pack voltage measurement circuit according to the embodiment of the present invention can be mass-produced at a lower manufacturing cost. That is, since by connecting the relay resistor in parallel with the relay switch, even when the relay switch is disconnected, only a low-level battery pack voltage that is a portion of the battery pack voltage is applied due to the relay resistor, the present invention has the effect that a relay rated at, for example, 400 V is suitable for a voltage of 800 V.

[0030] In addition, in the present invention, since the battery pack voltage is branched through the first branch unit and the second branch unit, two different battery pack voltages can be measured. That is, since the battery pack voltage of 400V is branched through the first branch unit and the battery pack voltage of 800V is branched through the second branch unit, the battery pack voltage of 400V or 800V can be measured by using one battery pack voltage measurement circuit. Therefore, one battery pack voltage measurement circuit can be used for a system applying a 400V battery pack and a system applying an 800V battery pack, and therefore, there is no need to develop different battery pack voltage measurement circuits, thereby reducing product development costs, etc.

[0031] In addition, since the battery pack voltage measurement circuit can be controlled by the first switch of the first branch unit and the second switch of the second branch unit of the present invention, the occurrence of leakage current due to the relay resistance can be prevented even when the relay switch is disconnected. That is, assuming that there is no first switch and second switch, when the relay switch is disconnected, leakage current may be generated through the relay resistance, but when the relay switch is disconnected, the first switch and the second switch also remain disconnected, thereby preventing the occurrence of leakage current. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a circuit diagram of a battery pack voltage measurement circuit according to an embodiment of the present invention.

[0033] Figures 2 to 4 : is a circuit diagram showing the flow of current for explaining a driving method of a battery pack voltage measurement circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and these embodiments are provided only to make the disclosure of the present invention complete and allow those skilled in the art to fully understand the scope of the present invention.

[0035] Figure 1 is a circuit diagram of a battery pack voltage measurement circuit according to an embodiment of the present invention.

[0036] Reference Figure 1, the battery pack voltage measurement circuit according to an embodiment of the present invention includes a first branch unit 100, a second branch unit 200, a relay unit 300, and a voltage distribution unit 400 connected between a battery pack voltage input terminal (ie, a power terminal Vpack) and a ground terminal GND. More specifically, the battery pack voltage measurement circuit according to an embodiment of the present invention includes a first branch unit 100 and a second branch unit 200 connected in parallel between the power terminal Vpack and a first node Q11, a relay unit 300 connected between the first node Q11 and the second node Q12, and a voltage distribution unit 400 connected between the second node Q12 and the ground terminal GND. Here, the first branch unit 100 and the second branch unit 200 set the path of the current input from the power terminal Vpack to the first path and the second path. In addition, the relay unit 300 includes a relay switch RS11 and a relay resistor (ie, a third resistor R13) connected in parallel, and the measurement of the battery pack voltage is performed and stopped by the on / off operation of the relay switch S13. In addition, the voltage distribution unit 400 divides and outputs the voltage of the current input through the first path or the second path to measure the voltage output to the output terminal DEC. The battery pack voltage measurement circuit according to the embodiment of the present invention will be described in more detail for each component.

[0037] 1. The first branch unit

[0038] The first branch unit 100 is connected between the power terminal Vpack and the first node Q11, and is connected in parallel with the second branch unit 200. The first branch unit 100 may include a first resistor R11 and a first switch S11 connected in series between the power terminal Vpack and the first node Q11. That is, the first resistor R11 and the first switch S11 are connected in series between the power terminal Vpack and the first node Q11 to form the first branch unit 100. The first branch unit 100 sets a current to flow through the first branch unit 100 in a first path according to the battery pack voltage. That is, when a first current according to a first voltage is applied from the power terminal Vpack, the first branch unit 100 is driven so that a current flows through the first branch unit 100 in a first path. Here, the first voltage of the battery pack may be 400V. That is, when the battery pack voltage is 400V, a current flows through the first branch unit 100.

[0039] The first switch S11 may be a FET driven according to a first control signal CTRL1 of a control unit (not shown). When the battery pack voltage is a first voltage, i.e., 400V, the control unit generates a first control signal CTRL1, and thus drives the first switch S11 so that current flows through the first branch unit 100. For example, when the battery pack voltage is 400V, the first control signal CTRL1 is output at a logic high level to drive the first switch S11. Of course, when the battery pack voltage is a second voltage higher than the first voltage, the first control signal CTRL1 is not generated, thereby disconnecting the first switch S11. For example, when the battery pack voltage is 800V, the first control signal CTRL1 is output at a logic low level to disconnect the first switch S11. In addition, the first branch unit 100 reduces the battery pack voltage and provides the voltage to the relay unit 300. That is, the first branch unit 100 reduces the battery pack voltage of 400V through the first resistor R11 and provides the voltage to the relay unit 300. Therefore, even when the battery pack voltage of 400 V is applied to the power terminal Vpack, the voltage dropped by the first resistor R11 is applied to the relay unit 300 .

[0040] In addition, the battery pack voltage measurement circuit of the present invention provides a voltage of 400V to the voltage distribution unit 400 through the first branch unit 100, and outputs the voltage after dividing the voltage by 100:1, for example. Therefore, the resistance value of the first resistor R11 may have a predetermined ratio with the resistance values ​​of the fourth resistor R14 and the fifth resistor R15 of the voltage distribution unit 400. For example, if the fourth resistor R14 is 1MΩ and the fifth resistor R15 is 20KΩ, the first resistor R11 may have a resistance value of 1MΩ. In this way, the resistance value of the first resistor R11 has a predetermined ratio with the resistance values ​​of the fourth resistor R14 and the fifth resistor R15, so that the voltage of 400V passing through the first branch unit 100 can be divided by 100:1 and output to the output terminal DEC.

[0041] 2. Second branch unit

[0042] The second branch unit 200 is connected between the power terminal Vpack and the first node Q11, and is connected in parallel with the first branch unit 100. The second branch unit 200 may include a second resistor R12 and a second switch S12 connected in series between the power terminal Vpack and the first node Q11. That is, the second resistor R12 and the second switch S12 are connected in series between the power terminal Vpack and the first node Q11 to form the second branch unit 200. The second branch unit 200 sets a current to flow through the second branch unit 200 in a second path according to the battery pack voltage. That is, when a second current according to a second voltage is applied from the power terminal Vpack, the second branch unit 200 is driven so that the current flows through the second branch unit 200 in a second path. Here, the second voltage of the battery pack may be 800V. That is, when the battery pack voltage is 800V, the current flows through the second branch unit 200.

[0043] The second switch S12 may be a FET driven by a second control signal CTRL2 of a control unit (not shown). When the battery pack voltage is a second voltage, i.e., 800V, the control unit generates a second control signal CTRL2, and therefore, drives the second switch S12 so that current flows through the second branch unit 200. For example, when the battery pack voltage is 800V, the second control signal CTRL2 is output at a logic high level to drive the second switch S12. Of course, when the battery pack voltage is a first voltage lower than the second voltage, the second control signal CTRL2 is not generated, so the second switch S12 is disconnected. For example, when the battery pack voltage is 400V, the second control signal CTRL2 is output at a logic low level to disconnect the second switch S12. In addition, the second branch unit 200 reduces the battery pack voltage and provides the voltage to the relay unit 300. That is, the second branch unit 100 reduces the battery pack voltage of 800V through the second resistor R12 and supplies the voltage to the relay unit 300. Therefore, even when the battery pack voltage of 800 V is applied to the power terminal Vpack, the voltage dropped by the second resistor R12 is applied to the relay unit 300 .

[0044] In addition, the battery pack voltage measurement circuit of the present invention provides an 800V voltage to the voltage distribution unit 400 through the second branch unit 200, and outputs the voltage after dividing the voltage by 200:1. Therefore, the resistance value of the second resistor R11 can have a predetermined ratio with the resistance values ​​of the fourth resistor R14 and the fifth resistor R15 of the voltage distribution unit 400. For example, if the fourth resistor R14 is 1MΩ and the fifth resistor R15 is 20KΩ, the second resistor R11 can have a resistance value of 3MΩ. In this way, the resistance value of the second resistor R11 has a predetermined ratio with the resistance values ​​of the fourth resistor R14 and the fifth resistor R15, so that the 800V voltage passing through the second branch unit 200 can be divided by 200:1 and output to the output terminal DEC.

[0045] 3. Relay unit

[0046] The relay unit 300 is connected between the first node Q11 and the second node Q12. That is, the relay unit 300 is arranged between the first branch unit 100 and the second branch unit 200 connected in parallel and the voltage distribution unit 400. The relay unit 300 may include a third switch (i.e., a relay switch S13) and a third resistor (i.e., a relay resistor R13). At this time, the relay switch R13 and the relay resistor R13 are connected in parallel between the first node Q11 and the second node Q13. The relay switch R13 is driven by a control signal (not shown) to measure the battery pack voltage, and provides the voltage distribution unit 400 with the voltage passing through the first branch unit 100 or the second branch unit 200. That is, when a control signal (not shown) is generated to measure the battery pack voltage and the control signal is applied to the relay switch S13, the relay switch S13 is turned on to provide the voltage distribution unit 400 with the voltage passing through the first branch unit 100 or the second branch unit 200.

[0047] The relay switch S13 is not shown in detail in the drawings, but may include a solenoid and a switch. The on / off operation of the relay switch S13 may be controlled based on the magnetic force generated in the solenoid. In addition, the relay resistor R13 is connected in parallel with the relay switch S13, so that when the relay switch S13 is disconnected, the voltage applied to the opposite end of the relay switch S13 is the same as the voltage applied to the opposite end of the relay resistor R13.

[0048] In addition, in the case of the prior art without the relay resistor R13, when the relay switch S13 is disconnected, most of the battery pack voltage is applied to the opposite end of the relay switch S13, so that if the battery pack voltage is a high voltage such as 800V, a higher rated relay may be required. However, since by connecting the relay resistor R13 in parallel with the relay switch S13, even when the relay switch S13 is disconnected, only a low-level battery pack voltage as a part of the battery pack voltage is applied due to the relay resistor R13, the present invention has an effect suitable for a voltage of 800V through a relay rated at, for example, 400V. That is, since the voltage dropped by the first branch unit 100 or the second branch unit 200 is applied to one side of the relay switch S13, the relay switch S13 can be designed as a low-end relay element. In addition, since the voltage dropped by the first branch unit 100 or the second branch unit 200 and the relay resistor R13 is applied to the other side of the relay switch S13, a stable on / off operation can be guaranteed even when the relay switch S13 is used as a low-spec relay switch.

[0049] In addition, since the battery pack voltage measurement circuit can be controlled by the first switch S11 of the first branch unit 100 and the second switch S12 of the second branch unit 200 of the present invention, the occurrence of leakage current due to the relay resistor R13 can be prevented even when the relay switch S13 is disconnected. That is, assuming that the first switch S11 and the second switch S12 do not exist, when the relay switch S13 is disconnected, leakage current may occur through the relay resistor R13, but when the relay switch S13 is disconnected, the first switch S11 and the second switch S12 also remain disconnected, thereby preventing the occurrence of leakage current due to the resistor R13.

[0050] In addition, the resistance value of the relay resistor R13 may be determined to satisfy the following Formula 1.

[0051] [Formula 1]

[0052]

[0053] Formula 1 does not include the ADC output circuit (ie, the fifth resistor R15). Here, R12, R13, and R14 are the resistance values ​​of the second resistor R12, the relay resistor R13, and the fourth resistor R14, respectively. V lim is the allowable voltage value of the relay switch S13, and Vo represents the voltage of the battery pack. In addition, since the second resistor R12 of the second branch unit 200 is greater than the first resistor R11 of the first branch unit 100, the resistance value of the relay resistor R13 in Formula 1 is affected by the resistance value of the second resistor R12.

[0054] As shown in Formula 1, the allowable voltage value V of relay element S13 is lim The voltage value Vo of the battery pack is reduced by the resistance value of each of the second resistor R12, the relay resistor R13 and the fourth resistor R14. Therefore, even when the voltage value Vo of the battery pack increases from 400V to 800V, the allowable voltage value V of the relay switch S11 can be satisfied if the resistance values ​​of the second resistor R12, the relay resistor R13 and the fourth resistor R14 are appropriately designed. lim Here, even when the voltage value Vo of the battery pack is 800V, the allowable voltage value V lim The fact that is satisfied means that even when a low-specification relay switch S13 is used, the voltage Vo of the battery pack having a high voltage can be stably measured. In addition, when the relay switch S13 is disconnected, the voltage dropped by the first resistor R11 or the second resistor R12 is applied to one end of the relay switch S13, and the same voltage as the voltage applied to the opposite end of the relay resistor R13 is applied to the opposite end of the relay switch S13. Therefore, even when a low-specification relay switch S13 is used, the disconnection operation of the relay switch S13 can be stably performed.

[0055] As described above, through these configurations and operations, the battery pack voltage measurement circuit according to the embodiment of the present invention provides an environment in which a low-specification relay switch S13 can be used.

[0056] Furthermore, the resistance value of the relay resistor R13 is determined so as to satisfy the following formula 2.

[0057] [Formula 2]

[0058]

[0059] Formula 1 is a formula including the ADC output circuit (ie, the fifth resistor R13). Here, R12, R13, R14, and R15 are the resistance values ​​of the second resistor R12, the relay resistor R13, the fourth resistor R14, and the fifth resistor R15, respectively. V lim is the allowable voltage value of the relay switch S13, and Vo represents the voltage of the battery pack.

[0060] Formula 2 is similar to Formula 1. The allowable voltage value V of relay switch S13 is limThe voltage value Vo of the battery pack may be less than the voltage value Vo of the battery pack, and the voltage value Vo of the battery pack is applied at a voltage that reduces the resistance values ​​of the second resistor R12, the relay resistor R13, the fourth resistor R14, and the fifth resistor R15. Specifically, in Formula 2, the voltage value Vo of the battery pack may be controlled to reduce the resistance value of the fifth resistor R15, which means that the voltage value Vo of the battery pack may be included in the allowable voltage value V of the relay switch S13 even when it becomes higher. lim middle.

[0061] As described above, since a low-specification relay switch S13 can be used in the battery pack voltage measurement circuit according to an embodiment of the present invention, the battery pack voltage measurement circuit can be mass-produced at a lower manufacturing cost. In addition, since the battery pack voltage measurement circuit can be controlled by the first switch S11 of the first branch unit 100 and the second switch S12 of the second branch unit 200 of the present invention, even when the relay switch S13 is disconnected, the occurrence of leakage current due to the relay resistor R13 can be prevented. That is, when the relay switch S13 is disconnected, the first switch S11 and the second switch S12 also remain disconnected, thereby preventing the occurrence of leakage current due to the relay resistor R13.

[0062] 4. Voltage distribution unit

[0063] The voltage distribution unit 400 is connected between the second node Q12 and the ground terminal GND. The voltage distribution unit 400 divides and outputs the voltage of the current input through the first path or the second path to measure the voltage output to the output terminal DEC. That is, the voltage distribution unit 400 divides the battery pack voltage Vpack supplied by the first branch unit 100 and the relay unit 300 and outputs the voltage to the output terminal DEC, and divides the battery pack voltage Vpack supplied by the second branch unit 200 and the relay unit 300 and outputs the voltage to the output terminal DEC. At this time, the battery pack voltage supplied by the first branch unit 100 is 400V, and the battery pack voltage supplied by the second branch unit 200 is 800V. That is, the voltage distribution unit 400 divides the battery pack voltage of 400V or 800V and outputs the voltage to the output terminal DEC.

[0064] The voltage distribution unit 400 may include a fourth resistor R14 and a fifth resistor R15 connected in parallel between the second node Q12 and the ground terminal GND. At this time, the output terminal DEC is set between the fourth resistor 14 and the fifth resistor 15. That is, the fourth resistor R14 is connected between the second node Q12 and the output terminal DEC, and the fifth resistor node R15 is connected between the output terminal DEC and the ground terminal GND to form the voltage distribution unit 400. Therefore, the voltage distribution unit 400 divides the battery pack voltage by the fourth resistor R14 and the fifth resistor R15, and outputs the voltage to the output terminal DEC. In addition, at the output terminal DEC, a capacitor C11 connected in parallel with the fifth resistor R15 is set. In addition, the fourth resistor R14 and the fifth resistor R15 may have a predetermined resistance value. That is, the resistance values ​​of the fourth resistor R14 and the fifth resistor R15 may have a predetermined ratio with the resistance values ​​of the first resistor R11 and the second resistor R12. For example, the fourth resistor R14 may have a resistance value of 1MΩ, and the fifth resistor R15 may have a resistance value of 20KΩ. At this time, the first resistor R11 may have a resistance value of, for example, 1MΩ, and the second resistor R12 may have a resistance value of, for example, 3MΩ. In this way, the resistance values ​​of the fourth resistor and the fifth resistor have a predetermined ratio with the resistance values ​​of the first resistor R11 and the second resistor R12, respectively, so that the voltage of 400V passing through the first branch unit 100 can be divided by 100:1, and the voltage of 800V passing through the second branch unit 200 can be divided to be output to the output terminal DEC.

[0065] As described above, since a low-specification relay switch S13 can be used in the battery pack voltage measurement circuit according to an embodiment of the present invention, the battery pack voltage measurement circuit can be mass-produced at a lower manufacturing cost. That is, because by connecting the relay resistor R13 in parallel with the relay switch S13, even when the relay switch S13 is disconnected, due to the relay resistor R13, only a low-level battery pack voltage as a part of the battery pack voltage is applied, so the present invention has, for example, an effect that a relay with a 400V rating is suitable for an 800V voltage. In addition, since the battery pack voltage measurement circuit can be controlled by the first switch S11 of the first branch unit 100 of the present invention and the second switch S12 of the second branch unit 200, even when the relay switch S13 is disconnected, the occurrence of leakage current caused by the relay resistor R13 can be prevented. That is, assuming that there are no first switch S11 and second switch S12, when the relay switch S13 is disconnected, leakage current may occur through the relay resistor R13, but when the relay switch S13 is disconnected, the first switch S11 and the second switch S12 also remain disconnected, thereby preventing the occurrence of leakage current caused by the resistor R13. In addition, in the present invention, since the battery pack voltage is branched through the first branch unit 100 and the second branch unit 200, two different battery pack voltages can be measured. That is, since the battery pack voltage of 400V is branched through the first branch unit 100 and the battery pack voltage of 800V is branched through the second branch unit 200, the battery pack voltage of 400V or 800V can be measured by using one battery pack voltage measurement circuit. Therefore, one battery pack voltage measurement circuit can be used for a system applying a 400V battery pack and a system applying an 800V battery pack, and therefore, there is no need to develop different battery pack voltage measurement circuits, thereby reducing product development costs, etc.

[0066] Figures 2 to 4 1 is a circuit diagram showing current flow for explaining a driving method of a battery pack voltage measurement circuit according to an embodiment of the present invention. That is, Figure 2 is a circuit diagram showing the flow of current when the battery pack voltage is 400V, Figure 3 is a circuit diagram showing the flow of current when the battery pack voltage is 800V, and Figure 4 is a circuit diagram for explaining a driving method when a switch is turned off.

[0067] Reference Figure 2, the relay switch S13 can be turned on by a predetermined control signal to measure the battery pack voltage. At this time, the control unit (not shown) can output the first control signal CTRL1 or the second control signal CTRL2 according to the battery pack voltage, and when the battery pack voltage is, for example, 400V, the first control signal CTRL1 can be output at a high level, and the second control signal CTRL2 can be output at a low level. When the first switch S11 is turned on by the high-level first control signal CTRL1, the current according to the battery pack voltage flows through the first path, that is, the first branch unit 100. That is, when the first control signal is applied at a high level, the battery pack voltage of 400V is supplied to the relay unit 300 through the first path, and then supplied to the voltage distribution unit 400. At this time, a voltage drop is generated by the first branch unit 100 and the relay unit 300, and the voltage distribution unit 400 divides the dropped battery pack voltage and outputs the voltage to the output terminal DEC. In addition, the first resistor R11, the fourth resistor R14, and the fifth resistor R15 have a predetermined resistance value, so the battery pack voltage is reduced by, for example, 100:1 and output to the output terminal DEC. In order to reduce the battery pack voltage of 400V by 100:1 and output the voltage, the first resistor R11, the fourth resistor R14, and the fifth resistor R15 can have resistance values ​​of 1MΩ, 1MΩ, and 20KΩ, respectively. Finally, the 400V battery pack voltage can be reduced and divided by the first branch unit 100, the relay unit 300, and the voltage distribution unit 500 and output to the output terminal DEC, and the output value of the output terminal DEC can be input to the analog-to-digital converter of the control unit (not shown) (ie, MCU).

[0068] Reference Figure 3, the relay switch S13 can be turned on by a predetermined control signal to measure the battery pack voltage. At this time, the control unit (not shown) can output the first control signal CTRL1 or the second control signal CTRL2 according to the battery pack voltage, and when the battery pack voltage is, for example, 800V, the second control signal CTRL2 can be output at a high level, and the first control signal CTRL1 can be output at a low level. When the second switch S12 is turned on by the high-level second control signal CTRL2, the current according to the battery pack voltage flows through the second path, that is, the second branch unit 200. That is, when the second control signal is applied at a high level, the battery pack voltage of 800V is supplied to the relay unit 300 through the second path, and then supplied to the voltage distribution unit 400. At this time, a voltage drop is generated by the second branch unit 200 and the relay unit 300, and the voltage distribution unit 400 divides the dropped battery pack voltage and outputs the voltage to the output terminal DEC. In addition, the second resistor R12, the fourth resistor R14, and the fifth resistor R15 have a predetermined resistance value, so the battery pack voltage is reduced by, for example, 200:2 and output to the output terminal DEC. In order to reduce the battery pack voltage of 800V by about 200:1 and output the voltage, the second resistor R12, the fourth resistor R14, and the fifth resistor R15 may have resistance values ​​of 3MΩ, 1MΩ, and 20KΩ, respectively. Ultimately, the 800V battery pack voltage can be reduced and divided by the second branch unit 200, the relay unit 300, and the voltage distribution unit 500 and output to the output terminal DEC, and the output value of the output terminal DEC can be input to the analog-to-digital converter of the control unit (not shown) (ie, MCU).

[0069] Reference Figure 4 , when the battery pack voltage is not measured, the relay switch S13 can be disconnected by a predetermined control signal. At this time, in the control unit (not shown), when the relay switch S13 is disconnected, the first control signal CTRL1 and the second control signal CTRL2 can be output in a low state. Therefore, the first switch S11 and the second switch S12 can be disconnected. Since the relay switch S13 and the first switch S11 and the second switch S12 are both disconnected, the leakage current caused by the relay resistor R13 can be prevented. That is, assuming that the first switch S11 and the second switch S12 do not exist, when the relay switch S13 is disconnected, a leakage current may occur through the relay resistor R13, but when the relay switch S13 is disconnected, the first switch S11 and the second switch S12 also remain disconnected, thereby preventing the occurrence of leakage current caused by the resistor R13.

[0070] Although the technical spirit of the present invention as described above has been specifically described according to the above embodiments, it should be noted that the above embodiments are for illustration rather than limitation. In addition, those skilled in the art will understand that there may be various embodiments within the scope of the technical spirit of the present invention.

[0071] The names of reference numerals used in the specification and drawings of the present invention are as follows.

[0072] 100: first branch unit 200: second branch unit

[0073] 300: Relay unit 400: Voltage distribution unit

Claims

1. A battery pack voltage measurement circuit, the battery pack voltage measurement circuit comprising: a relay unit, the relay unit controlling battery pack voltage measurement; a first branch unit and a second branch unit, the first branch unit and the second branch unit being disposed between a battery pack voltage input terminal and the relay unit and branching the battery pack voltage into different paths according to the battery pack voltage and then supplying the branched voltage to the relay unit; and A voltage distribution unit divides a battery pack voltage supplied through the first branch unit or the second branch unit and the relay unit, and outputs the divided battery pack voltage to an output terminal.

2. The battery pack voltage measurement circuit according to claim 1, wherein: The first branch unit includes a first resistor and a first switch connected in series between the battery pack voltage input terminal and the relay unit.

3. The battery pack voltage measurement circuit according to claim 2, wherein: The second branch unit includes a second resistor and a second switch, which are connected in series between the battery pack voltage input terminal and the relay unit and are connected in parallel with the first resistor and the first switch, respectively.

4. The battery pack voltage measurement circuit according to claim 3, wherein: The relay unit includes a relay switch and a third resistor, and the relay switch and the third resistor are connected in parallel between a connection point between the first branch unit and the second branch unit and the voltage distribution unit. 5 . The battery pack voltage measurement circuit according to claim 4 , further comprising a control unit for controlling the first switch, the second switch and the relay switch.

6. The battery pack voltage measurement circuit according to claim 5, wherein: The control unit selectively opens and closes the first switch and the second switch according to the magnitude of the battery pack voltage.

7. The battery pack voltage measurement circuit according to claim 4, wherein: A first resistance ratio which is a ratio between the sum of the resistances of the voltage distribution unit and the first resistance and a second resistance ratio which is a ratio between the sum of the resistances of the voltage distribution unit and the second resistance are set to be different from each other.

8. A battery pack voltage measurement circuit, the battery pack voltage measurement circuit comprising: a first branch unit, the first branch unit being arranged between the battery pack voltage input terminal and the first node to branch out a first battery pack voltage; a second branch unit, the second branch unit being disposed between the battery pack voltage input terminal and the first node and connected in parallel with the first branch unit to branch out a second battery pack voltage; a relay unit provided between the first node and the second node and controlling measurement of a battery pack voltage according to a switch operation; as well as A voltage distribution unit is provided between the second node and a ground terminal and divides a battery pack voltage supplied through the first branch unit or the second branch unit and the relay unit and then outputs the voltage to an output terminal.

9. The battery pack voltage measurement circuit according to claim 8, wherein: The first branch unit includes a first resistor and a first switch connected in series between the battery pack voltage input terminal and the first node.

10. The battery pack voltage measurement circuit according to claim 9, wherein: The second branch unit includes a second resistor and a second switch which are connected in series between the battery pack voltage input terminal and the first node and are connected in parallel with the first resistor and the first switch, respectively.

11. The battery pack voltage measurement circuit according to claim 10, wherein: The relay unit includes a relay switch and a third resistor connected in parallel between the first node and the second node. 12 . The battery pack voltage measurement circuit according to claim 11 , further comprising a control unit for controlling the first switch, the second switch and the relay switch.

13. The battery pack voltage measurement circuit according to claim 12, wherein: The control unit selectively opens and closes the first switch and the second switch according to the magnitude of the battery pack voltage.

14. The battery pack voltage measurement circuit according to claim 11, wherein: A resistance value of the first resistor and a resistance value of the second resistor are different from each other.

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