KR20210074702A - Apparatus and method for battery current measurement, and battery pack - Google Patents

Abstract

A battery current measuring device includes: a shunt resistor installed in a current path for charging and discharging a battery; a constant current circuit electrically connected in parallel to the shunt resistor; and a control unit operatively coupled to the shunt resistor and the constant current circuit. The constant current circuit is configured to supply a reference current to the shunt resistor when a diagnostic command is output by the control unit. The control unit is configured to diagnose the shunt resistor based on a voltage across the shunt resistor induced by the reference current. Accordingly, it is possible to diagnose whether the shunt resistor is abnormal.

Description

Apparatus and method for battery current measurement, and battery pack

The present invention relates to a technique for determining battery current using a shunt resistor.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable telephones is rapidly increasing and the development of electric vehicles, energy storage batteries, robots, satellites, etc. is in full swing, high-performance batteries that can be repeatedly charged and discharged have been developed. Research is being actively conducted.

Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. Among them, lithium batteries have almost no memory effect compared to nickel-based batteries, so they are free to charge and discharge and have a very high self-discharge rate. It is attracting attention due to its low energy density and high energy density.

Shunt resistors are widely used to measure battery current according to Op's law. However, the shunt resistor gradually deteriorates as the battery current repeatedly flows. In addition, a defect (eg, a crack) may occur in the shunt resistor due to accumulation of external shocks, or a coupling force between the shunt resistor and the path of the battery current may be weakened. Due to these various causes, the actual resistance of the shunt resistor increases over the initial resistance.

It is self-evident that the calculated battery current based on the initial resistance instead of the actual resistance of the shunt resistor will have a significant difference from the actual battery current, which cannot adequately protect the battery from abnormal situations such as overcharging and overdischarging.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide an apparatus and method for diagnosing whether a shunt resistor is abnormal, and a battery pack including the apparatus.

Other objects and advantages of the present invention may be understood by the following description, and will become more clearly understood by the examples of 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.

An apparatus for measuring battery current according to an aspect of the present invention includes: a shunt resistor installed in a current path for charging and discharging a battery; a constant current circuit electrically connected in parallel to the shunt resistor; and a control unit operatively coupled to the shunt resistor and the constant current circuit. The constant current circuit is configured to supply a reference current to the shunt resistor when a diagnostic command is output by the controller. The controller is configured to diagnose the shunt resistor based on a voltage across the shunt resistor induced by the reference current.

The controller may be configured to determine a first compensation value representing a ratio of a diagnostic voltage value to a reference voltage value corresponding to the reference current. The diagnostic voltage value represents a voltage across the shunt resistor. The controller may be configured to generate a fault message indicating that the shunt resistor is abnormal when the first compensation value is equal to or greater than a first threshold value.

The controller may be configured to determine a second compensation value indicating an absolute value of a difference between a reference voltage value corresponding to the reference current and a diagnostic voltage value. The diagnostic voltage value may represent a voltage across both ends of the shunt resistor. The controller may be configured to generate a fault message indicating that the shunt resistor is abnormal when the second compensation value is equal to or greater than a second threshold value.

The control unit may be configured to output the diagnosis command when charging and discharging of the battery is stopped.

The apparatus may further include a diagnostic switch electrically connected between the shunt resistor and the constant current circuit. The diagnostic switch is turned on in response to the diagnostic command.

The apparatus may further include a vibration motor for generating vibrations in the shunt resistor. The controller may be configured to determine a plurality of diagnostic voltage values representing a change in voltage across the shunt resistor while vibration is generated in the shunt resistor by the vibration motor. The controller may be configured to diagnose the shunt resistor based on the plurality of diagnostic voltage values.

The vibration motor may be configured to be driven by the reference current.

The controller may be configured to generate a fault message indicating that the shunt resistor is abnormal when a difference between a maximum value and a minimum value of the plurality of diagnostic voltage values is equal to or greater than a third threshold value.

A battery pack according to another aspect of the present invention includes the battery current measuring device.

A battery current measuring method according to another aspect of the present invention uses the battery current measuring device. The method includes: outputting, by the control unit, the diagnostic command to the constant current circuit; supplying, by the constant current circuit, the reference current to the shunt resistor when the diagnostic command is output by the controller; and diagnosing, by the controller, the shunt resistor based on a diagnostic voltage value representing a voltage across the shunt resistor induced by the reference current.

According to at least one of the embodiments of the present invention, while the battery current is cut off, it may be diagnosed whether the shunt resistor is abnormal based on the voltage across the shunt resistor by the reference current.

Also, according to at least one of the embodiments of the present invention, after determining the actual resistance of the shunt resistor, the battery current may be determined based on the actual resistance instead of the initial value.

Further, according to at least one of the embodiments of the present invention, while supplying a reference current to the shunt resistor and simultaneously generating an oscillation in the shunt resistor, monitoring the change in voltage across the shunt resistor to determine if the shunt resistor is abnormal. It can be diagnosed whether the coupling between the shunt resistor and the current path is loose, in particular.

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 the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so the present invention is a matter described in such drawings should not be construed as being limited only to
1 is a diagram exemplarily showing the configuration of a battery pack according to a first embodiment of the present invention, and FIG. 2 is a diagram exemplarily showing the configuration of the constant current circuit of FIG. 1 .
3 is a diagram exemplarily showing the configuration of a battery pack according to a second embodiment of the present invention, and FIG. 4 is a diagram exemplarily showing a relationship between the vibration motor and the shunt resistor of FIG. 3 .
5 is a flowchart illustrating an example of a battery current measuring method using the battery current measuring apparatus according to the first embodiment.
6 is a flowchart illustrating another example of a battery current measuring method using the battery current measuring apparatus according to the first exemplary embodiment.
7 is a flowchart illustrating an example of a battery current measuring method using the battery current measuring apparatus according to the second embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

Terms including an ordinal number such as 1st, 2nd, etc. are used for the purpose of distinguishing any one of various components from the others, and are not used to limit the components by such terms.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated. In addition, a term such as <control unit> described in the specification means a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

In addition, throughout the specification, when a part is "connected" with another part, it is not only "directly connected" but also "indirectly connected" with another element interposed therebetween. include

FIG. 1 is a diagram exemplarily showing the configuration of a battery pack 10 according to a first embodiment of the present invention, and FIG. 2 is a diagram exemplarily showing the configuration of the constant current circuit 110 of FIG. 1 .

Referring to FIG. 1 , a battery pack 10 includes a battery group 20 , a switching circuit 30 , and a device 100 for measuring battery current (hereinafter, may be referred to as a 'device 100 '). do.

The battery group 20 includes a plurality of battery cells 21 electrically connected in series and/or in parallel. The type of the battery cell 21 is not particularly limited as long as it can be repeatedly charged and discharged, such as a lithium ion cell.

The switching circuit 30 is provided to open and close a current path for charging and discharging the battery group 20 . The current path includes a first power line L ₁ and a second power line L ₂ . The switching circuit 30 may be installed on _{the first power line L 1} connecting the positive terminal of the battery group 20 and the first terminal of the battery pack 10 . The switching circuit 30 may include a charging FET (SW _C ) (Field Effect Transistor: FET) and a discharging FET (SW _D ). Charge FET SW _C and discharge FET SW _D are connected in series between _{node N 1} and node N ₂ of the current path. The switching circuit 30 may further include a precharge circuit. The precharge circuit is connected in parallel to the series circuit of the _{charging FET SW C} and the discharging FET SW _{D .} The precharge circuit includes a _{precharge FET SW P} and a precharge resistor R _P connected in series between a _{node N 1} and a node N ₂ .

The apparatus 100 comprises a shunt resistor (R _S), a constant current circuit 110 and the controller 130. The apparatus 100 may further include at least one of a diagnostic switch and a communication unit 120 .

The shunt resistor (R _S) is, may be mounted to the second power line (L ₂₎ connecting the second terminal between the negative electrode terminal and the battery pack 10 of the battery group (20). A first end and a second end of the shunt resistor (R _S) is, the second, etc. may be coupled through the respective welding or bolts to the node (N ₃₎ and a node (N ₄₎ of the power line (L _2).

The constant current circuit 110, the shunt resistor to the reference current (R _{S) (R} I) (for example, 10.0 A) is configured to supply the. The reference current I _R is a constant current having a predetermined current rate. The constant current circuit 110, and so that the electrical shunt resistor (R _S) physical without being affected by the resistance shunt resistor (R _S), the reference current (I _R) flows through a connected to it.

Referring to FIG. 2 , the constant current circuit 110 includes a constant voltage source 111 , a resistor R _C , and an operational amplifier 113 . The constant voltage source 111 may be, for example, a buck converter. The resistor R _C is connected between the inverting terminal of the operational amplifier 113 and the constant voltage source. The non-inverting terminal of the operational amplifier 113 may be grounded. The reference current I _R may be the input voltage V _IN from the constant voltage source 111 divided by the resistance of the resistor R _{C .}

Of course, the implementation of the constant current circuit 110 is not limited to that shown in FIG. 2 , and a known circuit capable of supplying a constant current, such as a current mirror, may be used as the constant current circuit 110 .

Diagnostic switch (SW _R) is electrically connected between the constant current circuit 110 and a shunt resistor (R _S). For example, as shown in FIG. 2 , the diagnostic switch SW _R may be connected between the node N ₄ and the output terminal of the operational amplifier 113 . Alternatively, the diagnostic switch SW _R may be connected between the node N ₃ and the inverting terminal of the operational amplifier 113 .

The diagnostic switch SW _R may open and close the current path 115 of the reference current I _{R .} Specifically, the diagnostic switch SW _R is turned on in response to a diagnostic command from the control unit 130 , and accordingly the reference current I _R from the constant current circuit 110 moves along the current path 115 . It is caused to flow through the shunt resistor (R _S). While the control unit 130 stops the output of the diagnosis command, the diagnosis switch (SW _R) is turned off, the flow of the shunt resistor (R _S), the reference current (I _R) via is blocked.

The communication unit 120 may be provided to be coupled to the external device 1 (eg, a charger) through a communication channel. The communication unit 120 may transmit a message (eg, a shutdown signal) from the external device 1 to the control unit 130 , and may transmit a message from the control unit 130 to the external device 1 . For communication between the communication unit 120 and the external device 1, for example, a wired network such as a local area network (LAN) and a controller area network (CAN) and/or a short-range wireless network such as Bluetooth, Zigbee, and Wi-Fi is utilized. can be

The control unit 130, the switching circuit 30, a shunt resistor (R _S), may be operatively coupled to the constant current circuit 110, a diagnostic switch (SW _R) and a communication unit 120.

The controller 130, in hardware, ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors (microprocessors) and may be implemented using at least one of electrical units for performing other functions.

The controller 130 may have a built-in memory. The memory may store a program and various data necessary for executing methods to be described later. The memory is, for example, a flash memory type, a hard disk type, a solid state disk type, an SDD type (Silicon Disk Drive type), and a multimedia card micro type. , at least one of random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and programmable read-only memory (PROM) may include a type of storage medium of

The controller 130 may output a diagnostic command when charging and discharging of the battery group 20 is stopped. When the charging and discharging of the battery group 20 are stopped, it means that the charging FET SW _C , the discharging FET SW _D , and the pre-charging FET SW _P are all turned off.

In response to the shutdown signal, the controller 130 may _{turn off all of the charging FET SW C} , the discharging FET SW _D , and the pre-charge FET SW _P , and then output a diagnostic command. This is intended to flow through the shunt resistor (R _S) the reference current (I _R), only the shunt resistor (R _S) for, and the battery current to 0 A to diagnose.

The controller 130 has a pair of sensing lines 131 and 132 . Sensing line 131 is electrically connected to the first end of the shunt resistor (R _S). Sensing line 132 is electrically connected to the second terminal of the shunt resistor (R _S).

The control unit 130, the voltage across the both ends of the shunt resistor (R _S) caused by the reference current (I _R) during the constant current circuit 110 is supplied to the reference current (I _R) to the shunt resistor (R _S) (V _S ) (hereinafter, may be referred to as a 'shunt voltage') is measured at least once, and a diagnostic voltage value representing the measured shunt voltage is determined.

The controller 130, based on the diagnosis voltage value, it is possible to diagnose the shunt resistor (R _S). Specifically, the control unit 130, by comparing the reference voltage value and the diagnosis voltage value, there is a shunt resistor (R _S) is possible to determine whether abnormal.

Is the actual resistance of the shunt resistor (R _S) is less than the threshold resistance, as a first stage when the second stage is that is rigidly secured to each node and the shunt resistor (R _S) of the shunt resistor (R _S) normal can do.

On the other hand, the shunt resistor of the actual resistance (R _S), or more than the threshold resistance, if true the coupling between the first stage and coupled between the node or the second end node of the shunt resistor (R _S) loose, the shunt resistor (R _S) abnormal It can be said that

The reference voltage value is a predetermined value indicating a voltage corresponding to the _{reference current I R .} The reference voltage value may be equal to the product of the initial resistance of the reference current value and a shunt resistor (R _S) representing the reference current (I _R). The initial resistance of the shunt resistor (R _S) is a predetermined value that indicates the resistance at which the shunt resistor (R _S) was not degraded new.

For example, the controller 130 may determine a first compensation value (eg, 1.2) representing a ratio of a diagnostic voltage value (eg, 0.012 V) to a reference voltage value (eg, 0.010 V). Then, the control unit 130, a first compensation value (e.g., 1.2) may be not less than a predetermined first threshold value (e.g., 1.1), diagnosed to be a shunt resistor (R _S) is abnormal.

As another example, the controller 130 may determine a second compensation value (eg, 0.002 V) indicating an absolute value of a difference between a reference voltage value (eg, 0.010 V) and a diagnostic voltage value (eg, 0.012 V). Then, the control unit 130, a second compensation value (for example, 0.002 V) is not less than a second critical value (for example, 0.001 V), can be diagnosed to be a shunt resistor (R _S) is abnormal.

Controller 130, a first compensation value or the second based on the compensation value, to compensate for the initial resistance, a determination of the actual resistance of the shunt resistor (R _S). The corrected initial resistance represents the actual resistance.

For example, when the initial resistance is 0.001 Ω and the first compensation value is 1.03, the actual resistance may be equal to 0.00103 Ω, which is the product of the first compensation value of 1.03 and the initial resistance of 0.001 Ω. As another example, if the initial resistance is 0.001 Ω, the second compensation value is 0.0005 V, and the reference current is 10.0 A, the actual resistance is the second compensation value of 0.0005 V divided by the reference current 10.0 A, the resistance increment of 0.00005 Ω, and the initial resistance of 0.001 Ω It can be equal to the sum of 0.00105 Ω.

When the battery group 20 is charged and discharged after the actual resistance is determined, the control unit 130 calculates a charging/discharging current value representing the battery current based _{on the actual resistance and the shunt voltage V S according to Op's law.} can decide When the battery group 20 is charged and discharged, it means that at least one of the _{charge FET SW C} , the discharge FET SW _D , and the precharge FET SW _{P is turned on.}

3 is a diagram exemplarily showing the configuration of the battery pack 10 according to the second embodiment of the present invention, and FIG. 4 is a diagram exemplarily showing the relationship between the vibration motor 140 and the shunt resistor of FIG. .

The second embodiment shown in FIG. 3 differs from the first embodiment in that the apparatus 100 further includes a vibration motor 140 . Accordingly, repeated descriptions of contents common to the first embodiment will be omitted, and differences will be mainly described.

3, the vibration motor 140, is provided to generate a vibration to the shunt resistor (R _S). The vibration motor 140 are electrically connected between the constant current circuit 110 and a shunt resistor (R _S). For example, the vibration motor 140 _{may be electrically connected between the node N 3} and the constant current circuit 110 (eg, the inverting terminal of the operational amplifier 1113 ). The vibration motor 140 may be configured to contact the shunt resistor (R _S).

The vibration motor 140 may be driven by a reference current (I _R), and generates a predetermined vibration pattern in the drive. In other words, the vibration motor 140 can be driven by the reference current (I _R) supplied through the meantime, the current path 115, a diagnostic switch (SW _R) is turned on.

The shunt resistor (R _S) the first end node (N _3), the contact area and the shunt resistor between the normal if, the vibration motor 140, the shunt resistor (R _S), even if vibrations are transmitted, the shunt resistor (R _S) in from the ( The contact area between the second end N _{4 of R S} and the node is kept constant. Thus, the shunt voltage (V _S) derived by the generation of vibration, a reference current (I _R) is to be constant.

On the other hand, the shunt resistor (R _S) is abnormal if, vibration occurred, the shunt resistor (R _S) of the second contact area between the end node of the first contact area or the shunt resistor (R _S) between the end node is not kept constant does not Therefore, during the vibration generation, the shunt voltage V _S induced by the reference current changes significantly.

The control unit 130, while by the vibration motor 140 where the vibration generated in the shunt resistor (R _S), at predetermined time intervals and measuring the shunt voltage (V _S), the shunt voltage (V _S) with the passage of time on the basis of the change, one can determine whether a shunt resistor (R _S) is normal. For example, the control unit 130, in the case of a plurality of diagnostic voltage values determined in sequence of the vibration generating the difference between the maximum value and the minimum value not less than the third threshold value, the shunt resistor (R _S), can be diagnosed as being abnormal.

5 is a flowchart illustrating an example of a battery current measuring method using the battery current measuring apparatus 100 according to the first embodiment.

1, 2 and 5 , in step S510 , the controller 130 outputs a diagnostic command. The controller 130 may stop charging and discharging of the battery group 20 in response to a shutdown signal from an external device and then output a diagnostic command.

In step S520, the constant current circuit 110, the diagnosis if the command is output, the shunt resistor (R _S), the reference current (I _R) by the control unit 130 is supplied. Along the current path 115, while a reference current (I _R) is, at least a predetermined reference time (for example, 1 second) can flow through the shunt resistor (R _S).

While supplied in step S530, the control unit 130, the reference current (I _R) is a shunt resistor (R _S), determines the diagnosis voltage value that represents the voltage (V _S) across both ends of the shunt resistor (R _S) do.

In step S540, control unit 130 determines the first compensation value represents the ratio of the diagnosis voltage value for a reference voltage value corresponding to the reference current (I _R).

In step S550 , the controller 130 determines whether the first compensation value is equal to or greater than a first threshold value. If the value of step S550 is “Yes”, the process may proceed to step S560. If the value of step S560 is “No”, the process may proceed to step S570.

In step S560, the control unit 130 generates a fault message indicating that the shunt resistor (R _S) is abnormal. The fault message may be transmitted to the external device 1 through the communication unit 120 .

In step S570, the control unit 130, based on the second compensation value, to determine the actual resistance of the shunt resistor (R _S).

6 is a flowchart illustrating another example of a battery current measuring method using the battery current measuring apparatus 100 according to the first exemplary embodiment.

1, 2 and 6 , in step S610 , the controller 130 outputs a diagnostic command. The controller 130 may stop charging and discharging of the battery group 20 in response to a shutdown signal from an external device and then output a diagnostic command.

In step S620, the constant current circuit 110, the diagnosis if the command is output, the shunt resistor (R _S), the reference current (I _R) by the control unit 130 is supplied. Along the current path 115, while a reference current (I _R) is, at least a predetermined reference time (for example, 1 second) can flow through the shunt resistor (R _S).

While supplied in step S630, the control unit 130, the reference current (I _R) is a shunt resistor (R _S), determines the diagnosis voltage value that represents the voltage (V _S) across both ends of the shunt resistor (R _S) do.

In step S640, control unit 130 determines the first compensation value represents the absolute value of the difference between the reference voltage value and the diagnosis voltage value corresponding to the reference current (I _R).

In step S650 , the controller 130 determines whether the second compensation value is equal to or greater than a second threshold value. If the value of step S650 is “Yes”, the process may proceed to step S660. If the value of step S660 is “No”, the process may proceed to step S670.

In step S660, the control unit 130 generates a fault message indicating that the shunt resistor (R _S) is abnormal. The fault message may be transmitted to the external device 1 through the communication unit 120 .

In step S670, the control unit 130, based on the second compensation value, to determine the actual resistance of the shunt resistor (R _S).

7 is a flowchart illustrating an example of a battery current measuring method using the battery current measuring apparatus 100 according to the second embodiment.

3, 4 and 7 , in step S710 , the controller 130 outputs a diagnostic command. The controller 130 may stop charging and discharging of the battery group 20 in response to a shutdown signal from an external device and then output a diagnostic command.

In step S720, the constant current circuit 110, the diagnosis if the command is output, the reference current (I _R) to the shunt resistor (R _S) and the vibration motor 140 by the controller 130 and supplies. The reference current (I _R), can flow through at least a predetermined reference time (for example, one second), while the current path along the shunt resistor (115) (R _S) and the vibration motor (140).

In step S730, the control unit 130, the reference current (I _R) is a shunt resistor (R _S) and the vibration during the supply to the motor 140, the voltage (V _S) across both ends of the shunt resistor (R _S) Determine a plurality of diagnostic voltage values representing changes.

In operation S740 , the controller 130 determines a voltage change value representing a difference between a maximum value and a minimum value among a plurality of diagnostic voltage values.

In step S750 , the control unit 130 determines whether the voltage change value is equal to or greater than a third threshold value. When the value of step S750 is “Yes”, the process may proceed to step S760. When the value of step S750 is “No”, the method according to FIG. 7 may be terminated. Alternatively, when the value of step S750 is “No”, step S540 of FIG. 5 or step S640 of FIG. 6 may be performed.

In step S760, the control unit 130 generates a fault message indicating that the shunt resistor (R _S) is abnormal, being (in particular, the combined poor). The fault message may be transmitted to the external device 1 through the communication unit 120 .

The embodiment of the present invention described above is not implemented only through the apparatus and method, and may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded. The implementation can be easily implemented by those skilled in the art to which the present invention pertains from the description of the above-described embodiments.

In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.

In addition, since the present invention described above can be various substitutions, modifications and changes within the scope that does not depart from the technical spirit of the present invention for those of ordinary skill in the art to which the present invention pertains, the above-described embodiments and attachments It is not limited by the illustrated drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications may be made.

10: battery pack
20: battery group 21: battery cell
30: switching circuit
100: battery current measuring device
R _S : shunt resistor
110: constant current circuit
120: communication department
130: control unit
140: vibration motor

Claims (10)

a shunt resistor installed in a current path for charging and discharging the battery;
a constant current circuit electrically connected in parallel to the shunt resistor; and
a control unit operatively coupled to the shunt resistor and the constant current circuit;
The constant current circuit is
configured to supply a reference current to the shunt resistor when a diagnostic command is output by the control unit;
The control unit is
and diagnose the shunt resistor based on a voltage across the shunt resistor induced by the reference current.
According to claim 1,
The control unit is
determine a first compensation value representing a ratio of a diagnostic voltage value to a reference voltage value corresponding to the reference current, wherein the diagnostic voltage value represents a voltage across the shunt resistor;
and generate a fault message indicating that the shunt resistor is abnormal when the first compensation value is greater than or equal to a first threshold value.
According to claim 1,
The control unit is
determine a second compensation value representing an absolute value of a difference between a reference voltage value corresponding to the reference current and a diagnostic voltage value, wherein the diagnostic voltage value represents a voltage across the shunt resistor;
and generate a fault message indicating that the shunt resistor is abnormal when the second compensation value is greater than or equal to a second threshold value.
According to claim 1,
The control unit is
and outputting the diagnostic command when charging and discharging of the battery is stopped.
According to claim 1,
a diagnostic switch electrically coupled between the shunt resistor and the constant current circuit;
The diagnostic switch is turned on in response to the diagnostic command.
According to claim 1,
Further comprising a vibration motor for generating vibration in the shunt resistor,
The control unit is
determine a plurality of diagnostic voltage values indicative of a change in voltage across the shunt resistor while vibration is generated in the shunt resistor by the vibration motor;
and diagnosing the shunt resistor based on the plurality of diagnostic voltage values.
7. The method of claim 6,
The vibration motor is
A battery current measuring device configured to be driven by the reference current.
7. The method of claim 6,
The control unit is
and diagnose that the shunt resistor is abnormal when a difference between a maximum value and a minimum value of the plurality of diagnostic voltage values is equal to or greater than a third threshold value.
A battery pack comprising the battery current measuring device according to any one of claims 1 to 8.
In the battery current measuring method using the battery current measuring device according to any one of claims 1 to 8,
outputting, by the control unit, the diagnostic command to the constant current circuit;
supplying, by the constant current circuit, the reference current to the shunt resistor when the diagnostic command is output by the controller; and
and diagnosing, by the controller, the shunt resistor based on a diagnostic voltage value representing a voltage across the shunt resistor induced by the reference current.

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