KR102620233B1 - Battery management system, battery pack including the same, and method for deteriming a failure of current detecting circuit - Google Patents

Abstract

A battery management system for determining whether a current detection circuit is malfunctioning, a battery pack including the same, and a method for determining a malfunction of a current detection circuit are disclosed. A battery management system according to an embodiment of the present invention includes a shunt resistance element installed in a high current path of a battery pack, and a first voltage flowing through the high current path based on the first voltage generated across both ends of the shunt resistance element. a current detection circuit configured to detect current; a two-way switch including a charge FET and a discharge FET connected in series with each other, and installed in the high current path; and a control unit operably coupled to the current detection circuit and the bidirectional switch. The control unit is configured to determine whether the current detection circuit is broken based on a second voltage generated at both ends of either the charge FET or the discharge FET.

Description

Battery management system, method for determining failure of battery pack and current measurement circuit including the same {BATTERY MANAGEMENT SYSTEM, BATTERY PACK INCLUDING THE SAME, AND METHOD FOR DETERIMING A FAILURE OF CURRENT DETECTING CIRCUIT}

The present invention relates to a battery management system for determining whether a current detection circuit is malfunctioning, a battery pack including the same, and a method for determining malfunction of a current detection circuit.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable phones has rapidly increased, and as the development of electric vehicles, energy storage batteries, robots, and satellites has begun, the need for high-performance batteries capable of repeated charging and discharging has increased. Research is actively underway.

Currently commercialized batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium batteries. Among these, lithium batteries have almost no memory effect compared to nickel-based batteries, so they can be freely charged and discharged, and have a very high self-discharge rate. It is attracting attention due to its low and high energy density.

A current detection circuit is installed in the high current path of the battery pack, and the current detection circuit detects the charge/discharge current flowing through the battery. Charge/discharge current is a basic and important parameter that is essential for calculating the state of charge (SOC) and state of health (SOH) of a battery. Therefore, charge/discharge current must be measured as accurately as possible.

Generally, the current detection circuit includes a shunt resistor element, and when the charge/discharge current flows through the shunt resistor element, the voltage measured at both ends of the shunt resistor element is divided by the resistance of the shunt resistor element, so that the charge/discharge current Detect.

However, due to various reasons, hardware failure (e.g., damage to the shunt resistor element, damage to the communication line) or software failure may occur in the current detection circuit. In this case, the charge/discharge current detected by the current detection circuit may be It is no longer trustworthy. Therefore, a technology capable of properly diagnosing a failure of a current detection circuit including a shunt resistance element is needed, and Patent Document 1 has been disclosed as prior art. Patent Document 1 determines whether the current detection circuit is broken by comparing the charge/discharge current detected using a shunt resistor element with the charge/discharge current detected using a Hall sensor.

However, since Patent Document 1 requires a Hall sensor, it has the disadvantage that the manufacturing cost is higher and the circuit becomes more complicated compared to a circuit that detects charge/discharge current using only a shunt resistance element.

(Patent Document 1) Republic of Korea Patent Publication No. 10-1810658 (Registration Date: December 13, 2017)

The present invention was developed to solve the above problems, and it is possible to determine whether a current detection circuit including a shunt resistance element is broken without adding a Hall sensor for detecting charge/discharge current in addition to the shunt resistance element. The purpose is to provide a battery management system, a battery pack including the same, and a method.

Other objects and advantages of the present invention can be understood from the following description and will be more clearly understood by practicing the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.

A battery management system according to an embodiment of the present invention includes a shunt resistance element installed in a high current path of a battery pack, and a first voltage flowing through the high current path based on the first voltage generated across both ends of the shunt resistance element. a current detection circuit configured to detect current; a two-way switch including a charge FET and a discharge FET connected in series with each other, and installed in the high current path; and a control unit operably coupled to the current detection circuit and the bidirectional switch. The control unit is configured to determine whether the current detection circuit is broken based on a second voltage generated at both ends of either the charge FET or the discharge FET.

The control unit is configured to apply a high level voltage to the gate of the charge FET and the gate of the discharge FET so that the charge FET and the discharge FET are in an on state.

The control unit uses the first current as an index to obtain an on-state resistance associated with a drain current corresponding to the first current as a reference resistance from a first lookup table. The first lookup table has data representing the relationship between drain currents and on-state resistance of the charge FET and the discharge FET. The control unit divides the second voltage by the reference resistance to calculate the second current. The control unit is configured to determine whether the current detection circuit is broken based on the difference between the first current and the second current.

The control unit uses the first current as an index to obtain a drain-source voltage associated with the drain current corresponding to the first current from a second lookup table as a reference voltage. The second lookup table has data representing the relationship between drain currents and drain-source voltages of the charge FET and the discharge FET. The control unit is configured to determine whether the current detection circuit is broken based on the difference between the second voltage and the reference voltage.

The control unit is configured to determine whether the current detection circuit is broken when the amount of change in the first current per unit time is outside the reference range.

The control unit determines a monitoring period based on the amount of change in the first current per unit time. The control unit is configured to periodically determine whether the current detection circuit is broken during the monitoring period. The monitoring period may be proportional to the size of the change amount.

The control unit is configured to output a diagnostic signal indicating whether the current detection circuit is malfunctioning.

A battery pack according to another embodiment of the present invention includes the battery management system.

A method for determining a failure of a current detection circuit according to another embodiment of the present invention includes the current detection circuit detecting a first current based on the first voltage generated at both ends of a shunt resistor element installed in a high current path of a battery pack. step; A control unit measuring a second voltage generated at both ends of either a charge FET or a discharge FET included in a bidirectional switch installed in the high current path; and the control unit determining whether the current detection circuit is broken based on the second voltage.

The step of determining whether the current detection circuit is broken based on the second voltage includes using the first current as an index to determine an on-state resistance associated with the drain current corresponding to the first current from a first lookup table. Obtaining as a reference resistance; dividing the second voltage by the reference resistance to calculate a second current; and determining whether the current detection circuit is broken based on the difference between the first current and the second current. The first lookup table has data representing the relationship between drain currents and on-state resistance of the charge FET and the discharge FET.

The step of determining whether the current detection circuit is broken based on the second voltage includes using the first current as an index to determine a drain-source voltage associated with the drain current corresponding to the first current from a second lookup table. Obtaining as a reference voltage; It may include determining whether the current detection circuit is broken based on the difference between the second voltage and the reference voltage. The second lookup table has data representing the relationship between drain currents and drain-source voltages of the charge FET and the discharge FET.

According to at least one of the embodiments of the present invention, it is possible to determine whether a current detection circuit including a shunt resistance element is broken without adding a Hall sensor for detecting charge/discharge current in addition to the shunt resistance element.

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

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later, so the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is a schematic diagram of a battery pack including a battery management system according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a graph corresponding to a first lookup table used to determine whether the current detection circuit of FIG. 1 is broken.
FIG. 3 is a diagram illustrating a graph corresponding to a second lookup table used to determine whether the current detection circuit of FIG. 1 is broken.
Figure 4 is a flowchart showing a method for determining a failure of a current detection circuit according to another embodiment of the present invention.
Figure 5 is a flowchart showing a method for determining a failure of a current detection circuit according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability.

Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

Additionally, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Terms containing ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms.

Throughout the specification, when a part is said to “include” a certain element, this means that it does not exclude other elements, but may further include other elements, unless specifically stated to the contrary.

Additionally, throughout the specification, when a part is said to be "connected" to another part, this refers not only to the case where it is "directly connected" but also to the case where it is "indirectly connected" with another element in between. Includes.

FIG. 1 is a schematic diagram of a battery pack 10 including a battery management system 100 according to an embodiment of the present invention, and FIG. 2 is a diagram used to determine whether the current detection circuit 120 of FIG. 1 is broken. This is a diagram illustrating a graph corresponding to the first lookup table, and FIG. 3 is an illustrative graph corresponding to the second lookup table used to determine whether the current detection circuit 120 of FIG. 1 is broken. This is a drawing showing.

Referring to FIG. 1, the battery pack 10 includes a battery stack 20 and a battery management system 100.

The battery stack 20 includes at least one battery cell 21. When a plurality of battery cells 21 are included in the battery stack 20, each battery cell 21 may be connected to other battery cells 21 in series or parallel. Each battery cell 21 may be, for example, a lithium ion battery. Of course, the type of battery cell 21 is not limited to lithium-ion batteries, and is not particularly limited as long as it can be repeatedly charged and discharged.

The battery management system 100 includes a bidirectional switch 110, a current detection circuit 120, and a control unit 200.

The two-way switch 110 is installed in the high current path 11. The bidirectional switch 110 may include a charging FET 111 and a discharging FET 112 connected in series with each other. The term FET stands for field effect transistor. The charging FET 111 may include a drain, gate, source, and parasitic diode. Discharge FET 112 may include a drain, gate, source, and parasitic diode.

For example, as shown in FIG. 1, the drain of the charge FET 111 is connected to the first power terminal (P+) of the battery pack 10, and the drain of the discharge FET 112 is connected to the battery stack 20. It is connected to the positive terminal, and the source of the charge FET 111 and the source of the discharge FET 112 may be connected to the common node 12 on the high current path 11.

As another example, unlike shown in FIG. 1, the positions of the charge FET 111 and the discharge FET 112 may be exchanged. That is, the source of the charging FET 111 is connected to the positive terminal of the battery stack 20, and the source of the discharging FET 112 is connected to the first power terminal (P+) of the battery pack 10. The drain of the charge FET 111 and the drain of the discharge FET 112 may be connected to the common node 12.

The gate of the charge FET 111 and the gate of the discharge FET 112 are connected to the control unit 200 . A high level voltage (eg, 5 V) selectively output from the control unit 200 is applied to the gate of the charge FET 111 and the gate of the discharge FET 112. The charge FET 111 and the discharge FET 112 operate in the on state while the high level voltage is output from the control unit 200, and operate in the off state while the output of the high level voltage from the control unit 200 is stopped. .

The parasitic diode of the charge FET (111) is connected between the drain and source of the charge FET (111). While the charge FET 111 is in the off state, the charge current is blocked by the parasitic diode of the charge FET 111. The parasitic diode of the discharge FET 112 is connected between the drain and source of the discharge FET 112. While the discharge FET 112 is in the off state, the discharge current is blocked by the parasitic diode of the discharge FET 112.

The current detection circuit 120 includes a shunt resistance element 121 and a microprocessor 122. The shunt resistance element 121 is installed in the high current path 11 of the battery pack 10. For example, as shown in FIG. 1, one end of the shunt resistance element 121 is connected to the negative terminal of the battery stack 20, and the other end is connected to the second power terminal (P-) of the battery pack 10. can be connected Of course, unlike what is shown in FIG. 1, one end of the shunt resistor element 121 may be connected to the positive terminal of the battery stack 20, and the other end may be connected to the drain of the discharge FET 112. Alternatively, one end of the shunt resistor element 121 may be connected to the drain of the charging FET 111, and the other end may be connected to the first power terminal (P+). The microprocessor 122 divides the voltage generated at both ends of the shunt resistance element 121 by the resistance of the shunt resistance element 121, so that the charge/discharge current flowing through the large current path 11 is controlled at a predetermined period ( Yes, it can be detected every 0.01 seconds. Hereinafter, the voltage generated across both ends of the shunt resistance element 121 will be referred to as 'first voltage', and the charge/discharge current detected by the current detection circuit 120 will be referred to as 'first current'. The microprocessor 122 is provided with a communication terminal (CI). The microprocessor 122 outputs current data representing the first current to the control unit 200 through the communication terminal (CI).

The control unit 200 is operably coupled to the current detection circuit 120 and the two-way switch 110. The control unit 200 includes a switch driver 210, a voltage detection circuit 220, and a controller 230.

The switch driver 210 is configured to selectively transition the bidirectional switch 110 from the on state to the off state or from the off state to the on state in response to an on command or an off command from the controller 230. Specifically, the switch driver 210 individually applies a high level voltage to the gate of the charge FET 111 and the gate of the discharge FET 112, thereby selectively controlling each of the charge FET 111 and the discharge FET 112. Control in on state. For example, in a normal mode in which a high level voltage is applied to both the gate of the charge FET 111 and the gate of the discharge FET 112, both the charge FET 111 and the discharge FET 112 are in an on state, thereby generating a charge current. Eddy discharge current may flow through the high current path 11. As another example, in a charging mode in which a high level voltage is applied only to the gate of the charge FET 111, the charge FET 111 is in an on state and the discharge FET 112 is in an off state, so the discharge current is blocked and the charge current Only the high current can flow through the path 11. Conversely, in the discharge mode in which a high level voltage is applied only to the gate of the discharge FET 112, the charge FET 111 is in an off state and the discharge FET 112 is in an on state, so the charge current is blocked and only the discharge current is This large current can flow through the path 11.

The voltage detection circuit 220 is configured to detect the voltage Va of the battery stack 20 and the voltage Vb of the first power terminal (P+), respectively. The voltage detection circuit 220 may be configured to additionally detect the voltage Vc of the common node 12. The voltage detection circuit 220 is provided with a communication terminal (CV). The voltage detection circuit 220 transmits voltage data representing at least one of the voltage Va of the battery stack 20, the voltage Vb of the first power terminal (P+), and the voltage Vc of the common node 12 to the communication terminal (CV). It is output to the controller 230 through.

The controller 230 is operably coupled to each of the current detection circuit 120, the switch driver 210, and the voltage detection circuit 220. The controller 230 is provided with a communication terminal C1, a communication terminal C2, a communication terminal C3, and a communication terminal C4. The controller 230 may continuously monitor changes in the first current over time based on current data from the current detection circuit 120 received through the communication terminal C1. The controller 230 controls the voltage of the battery stack 20, the voltage of the first power terminal (P+), and the common node ( Changes over time in at least one of the voltages in 12) can be continuously monitored. The controller 230 outputs an on command or an off command to the switch driver 210 through the communication terminal C3.

The controller 230 is hardware-wise comprised of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), and microprocessors ( It may be implemented to include at least one of microprocessors) and electrical units for performing other functions. Additionally, the controller 230 may be equipped with a memory device. For example, RAM, ROM, register, hard disk, optical recording medium, or magnetic recording medium may be used as the memory device. The memory device may store, update, and/or erase programs including various control logics executed by the controller 230, and/or data generated when the control logic is executed.

The controller 230 may monitor the voltage generated at both ends of the charge FET 111 and the discharge FET 112 based on the voltage data. The voltage generated across the charging FET 111 corresponds to the difference between the voltage Vb of the first power terminal (P+) and the voltage Vc of the common node 12. The voltage generated across the discharge FET 112 corresponds to the difference between the voltage Va of the battery stack 20 and the voltage Vc of the common node 12. Hereinafter, the voltage generated at both ends of the charging FET 111 and the discharging FET 112 that is in the on state will be referred to as the 'second voltage'.

If a predetermined condition is satisfied, the controller 230 may determine whether the current detection circuit 120 is broken based on the second voltage. That is, when a predetermined condition is satisfied, the controller 230 uses the second voltage to effectively cause the first current detected by the current detection circuit 120 to charge and discharge the current flowing through the high current path 11. It can be determined whether it represents something or not. The predetermined condition is that the amount of change in the first current during the most recently monitored unit time (eg, 0.1 second) is outside the reference range (eg, -50 to +50 A).

If the amount of change during a unit time of the first current is outside the standard range, the controller 230 may determine the monitoring period based on the amount of change during the unit time of the first current. The monitoring period may be proportional to the magnitude of change in the first current per unit time. For example, if the amount of change per unit time of the first current is 100 A, the monitoring period may be determined to be 2 seconds, and if the amount of change per unit time of the second current is 150 A, the monitoring period may be determined to be 3 seconds. During the monitoring period, it may be periodically determined whether the current detection circuit 120 is malfunctioning at predetermined time intervals (eg, 0.2 seconds).

The time when the first voltage is detected by the current detection circuit 120 and the time when the second voltage is detected by the voltage detection circuit 220 may only have a difference within a predetermined error range. The controller 230 can diagnose a failure of the current detection circuit 120 using at least one of the first lookup table and the second lookup table. Each diagnostic operation will now be described in detail.

<Diagnosis operation using the first lookup table>

Referring to FIGS. 1 and 2 , a first lookup table is previously stored in the memory device of the controller 230. The first lookup table has data representing the relationship between the drain current I _D of the charge FET 111 and the discharge FET 112 and the on-state resistance R _ON . As shown in Figure 2, as the drain current I _D of the charge FET 111 and the discharge FET 112 increases, the on-state resistance R _ON of the charge FET 111 and the discharge FET 112 increases nonlinearly. increases.

The controller 230 uses the first current as an index to obtain a reference resistance associated with the first current from the first lookup table. For example, if the first current is 100 A, an on-state resistance of 1 mΩ associated with a drain current of 100 A is obtained as the reference resistance, and if the first current is 150 A, an on-state resistance of 3 mΩ associated with a drain current of 150 A is obtained. An on-state resistance of 7 mΩ associated with a drain current of 200 A can be obtained as a reference resistance when the first current is 200 A.

Next, the controller 230 divides the second voltage by the reference resistance to calculate the second current.

Next, the controller 230 determines whether the current detection circuit 120 is broken based on the difference between the first current and the second current. The first current and the second current represent charging and discharging currents flowing through the large current path 11 at the same point in time. Accordingly, if the current detection circuit 120 is normal, the difference between the first current and the second current will be within the first predetermined threshold range (e.g., -0.3 A to +0.3 A), but if the current detection circuit 120 is malfunctioning, The difference between the first current and the second current will be outside the first threshold range.

<Diagnosis operation using the second lookup table>

Referring to FIGS. 1 and 3 , a second lookup table is previously stored in the memory device of the controller 230. The second lookup table has data representing the relationship between the drain current I _D of the charge FET 111 and the discharge FET 112 and the drain-source voltage V _DS . As shown in Figure 3, as the drain current I _D of the charge FET 111 and the discharge FET 112 increases, the drain-source voltage V _DS of the charge FET 111 and the discharge FET 112 becomes nonlinear. increases to

The controller 230 uses the first current as an index to obtain a reference voltage associated with the first current from the second lookup table. For example, when the first current is 100 A, a drain-source voltage of 0.1 V associated with a drain current of 100 A is obtained as the reference voltage, and when the first current is 150 A, a drain-source voltage of 0.45 V associated with a drain current of 150 A is obtained. A drain-source voltage of 1.4 V associated with a drain current of 200 A can be obtained as a reference voltage when the first current is 200 A.

Next, the controller 230 determines whether the current detection circuit 120 is broken based on the difference between the second voltage and the reference voltage. The second voltage is generated by the charge/discharge current, and the first current corresponds to the charge/discharge current. Therefore, if the current detection circuit 120 is normal, the difference between the second voltage and the reference voltage will be within the predetermined second threshold range (e.g., -0.01 V to +0.01 V), but if the current detection circuit 120 is malfunctioning, the difference between the second voltage and the reference voltage will be within the predetermined second threshold range (e.g., -0.01 V to +0.01 V). The difference between the 2 voltage and the reference voltage will be outside the second threshold range.

When the diagnosis operation using at least one of the above-described first lookup table and the second lookup table is completed, the controller 230 outputs a diagnosis signal indicating whether the current detection circuit 120 is broken. The diagnostic signal may be output from the communication terminal (C4) provided in the controller 230 and transmitted to an external device (eg, ECU of a vehicle) through the communication terminal (COM) of the battery pack 10. The communication terminal (COM) supports wired or wireless communication. Wired communication may be, for example, CAN (controller area network) communication, and wireless communication may be, for example, ZigBee or Bluetooth communication. If wired and wireless communication between the controller 230 and an external device is supported, the type of communication protocol is There is no particular limitation.

The external device may include a peripheral device configured to provide the user with at least one of visual information and auditory information corresponding to the diagnostic signal received from the controller 230. Peripheral devices may be implemented using devices that output information visually and/or audibly, such as displays and speakers.

Figure 4 is a flowchart showing a method for determining a failure of the current detection circuit 120 according to another embodiment of the present invention.

Referring to FIGS. 1, 2, and 4, in step 400, the current detection circuit 120 detects a first voltage generated across the shunt resistor element 121 installed in the high current path 11 of the battery pack 10. The first current is detected based on . The current detection circuit 120 transmits current data representing the first current to the control unit 200.

In step 410, the control unit 200 measures the second voltage generated at both ends of either the charge FET 111 or the discharge FET 112 installed in the large current path 11. For example, in the charging mode, the voltage generated across the charging FET 111 is measured as the second voltage, and in the discharging mode, the voltage generated across the discharging FET 112 is measured as the second voltage. In normal mode, the voltage generated across the charge FET 111 or the discharge FET 112 can be measured as the second voltage. The time at which the first voltage is measured and the time at which the second voltage is measured may be the same or may have a difference within an error range.

In step 420, the control unit 200 uses the first current as an index to obtain the on-state resistance associated with the drain current corresponding to the first current as a reference resistance from the first lookup table. In the first lookup table, data showing the relationship between the drain current and the on-state resistance of the charge FET 111 and the discharge FET 112 is recorded.

In step 430, the control unit 200 divides the second voltage by the reference resistance to calculate the second current. The second current is an estimate of the current flowing through the charge FET (111) and the discharge FET (112).

In step 440, the control unit 200 determines whether the difference between the first current and the second current exceeds the first threshold range. If the difference between the first current and the second current is outside the first threshold range, it indicates that the current detection circuit 120 is malfunctioning. If the value of step 440 is “YES,” step 450 proceeds.

In step 450, the control unit 200 outputs a diagnostic signal indicating that the current detection circuit 120 is malfunctioning.

Figure 5 is a flowchart showing a method for determining a failure of the current detection circuit 120 according to another embodiment of the present invention.

Referring to FIGS. 1, 3, and 5, in step 500, the current detection circuit 120 detects a first voltage generated at both ends of the shunt resistor element 121 installed in the high current path 11 of the battery pack 10. The first current is detected based on . The current detection circuit 120 transmits current data representing the first current to the control unit 200.

In step 510, the control unit 200 measures the second voltage generated at both ends of either the charge FET 111 or the discharge FET 112 installed in the large current path 11. The time at which the first voltage is measured and the time at which the second voltage is measured may be the same or may have a difference within an error range.

In step 520, the control unit 200 uses the first current as an index to obtain a drain-source voltage associated with the drain current corresponding to the first current from the second lookup table as a reference voltage. In the second lookup table, data representing the relationship between the drain current and drain-source voltage of the charge FET 111 and the discharge FET 112 is recorded.

In step 530, the control unit 200 determines whether the difference between the second voltage and the reference voltage is outside the second threshold range. If the difference between the second voltage and the reference voltage is outside the second threshold range, it indicates that the current detection circuit 120 is malfunctioning. If the value of step 530 is “YES,” step 540 proceeds.

In step 540, the control unit 200 outputs a diagnostic signal indicating that the current detection circuit 120 is malfunctioning.

According to the embodiments described in this specification, it is possible to determine whether the current detection circuit 120 including the shunt resistance element 121 is broken without adding a Hall sensor for detecting charge/discharge current in addition to the shunt resistance element 121. can be judged.

The embodiments of the present invention described above are not only implemented through devices and methods, but may also be implemented through a program that realizes the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. The implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the description below will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the patent claims.

In addition, the present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention to those of ordinary skill in the technical field to which the present invention pertains. It is not limited by the drawings, and all or part of each embodiment can be selectively combined so that various modifications can be made.

10: Battery pack
11: High current path
20: battery stack
21: battery cell
100: Battery management system
110: two-way switch
111: charge FET
112: discharge FET
CN: Common Node
120: current detection circuit
121: shunt resistance element
200: control unit
210: switch driver
220: voltage detection circuit
230: controller

Claims (12)

A current detection circuit comprising a shunt resistance element installed in a high current path of a battery pack and configured to detect a first current flowing through the large current path based on a first voltage generated across both ends of the shunt resistance element;
a two-way switch including a charge FET and a discharge FET connected in series with each other, and installed in the high current path; and
a control unit operably coupled to the current detection circuit and the bidirectional switch,
The control unit,
Measure a second voltage generated across either the charge FET or the discharge FET,
Using the first current as an index, an on-state resistance associated with a drain current corresponding to the first current is obtained as a reference resistance from a first lookup table, wherein the first lookup table determines the drain of the charge FET and the discharge FET. With data representing the relationship between current and on-state resistance,
Dividing the second voltage by the reference resistance to calculate a second current,
A battery management system, configured to determine whether the current detection circuit is broken based on the difference between the first current and the second current.
According to paragraph 1,
The control unit,
A battery management system configured to apply a high level voltage to at least one of the gate of the charge FET and the gate of the discharge FET so that at least one of the charge FET and the discharge FET has an on state.
delete A current detection circuit comprising a shunt resistance element installed in a high current path of a battery pack and configured to detect a first current flowing through the large current path based on a first voltage generated across the shunt resistance element;
a two-way switch including a charge FET and a discharge FET connected in series with each other, and installed in the high current path; and
a control unit operably coupled to the current detection circuit and the bidirectional switch;
The control unit,
Measure a second voltage generated across either the charge FET or the discharge FET,
Using the first current as an index, a drain-source voltage associated with a drain current corresponding to the first current is obtained as a reference voltage from a second lookup table, wherein the second lookup table is an index of the charge FET and the discharge FET. With data representing the relationship between drain current and drain-source voltage,
A battery management system, configured to determine whether the current detection circuit is broken based on the difference between the second voltage and the reference voltage.
According to paragraph 1,
The control unit,
A battery management system configured to determine whether the current detection circuit is broken when the amount of change in the first current during unit time is outside a reference range.
According to paragraph 1,
The control unit,
Determining a monitoring period based on the amount of change in the first current per unit time,
A battery management system configured to periodically determine whether the current detection circuit has failed during the monitoring period.
According to clause 6,
The monitoring period is proportional to the size of the change amount.
According to paragraph 1,
The control unit,
A battery management system configured to output a diagnostic signal indicating whether the current detection circuit has failed.
A battery pack comprising the battery management system according to any one of claims 1, 2, and 4 to 8.
A current detection circuit detecting a first current based on a first voltage generated at both ends of a shunt resistance element installed in a high current path of a battery pack;
A control unit measuring a second voltage generated at both ends of either a charge FET or a discharge FET included in a bidirectional switch installed in the high current path;
using the first current as an index to obtain an on-state resistance associated with a drain current corresponding to the first current as a reference resistance from a first lookup table;
dividing the second voltage by the reference resistance to calculate a second current; and
The control unit determines whether the current detection circuit is broken based on the difference between the second voltages,
The first lookup table has data indicating a relationship between drain currents and on-state resistance of the charge FET and the discharge FET.
delete A current detection circuit detecting a first current based on a first voltage generated at both ends of a shunt resistance element installed in a high current path of a battery pack;
A control unit measuring a second voltage generated at both ends of either a charge FET or a discharge FET included in a bidirectional switch installed in the high current path;
using the first current as an index to obtain a drain-source voltage associated with a drain current corresponding to the first current from a second lookup table as a reference voltage;
Comprising determining whether the current detection circuit is broken based on the difference between the second voltage and the reference voltage,
The second lookup table has data representing the relationship between drain currents and drain-source voltages of the charge FET and the discharge FET.

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