Patent Description:
Recently, there is dramatically growing demand for portable electronic products such as laptop computers, video cameras and mobile phones, and with the extensive development of electric vehicles, accumulators for energy storage, robots and satellites, many studies are being made on high performance batteries that can be recharged repeatedly.

Currently, commercially available batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium batteries and the like, and among them, lithium batteries have little or no memory effect, and thus they are gaining more attention than nickel-based batteries for their advantages of free charging and discharging, a very low self-discharge rate and high energy density.

A battery management system includes a circuit board on which components necessary to control and protect batteries, such as passive elements or active elements, are mounted. Typically, the passive elements include a resistor and a capacitor. The resistor is primarily used to interrupt an overcurrent to the batteries or peripheral circuitry according to the Ohm's law, and the capacitor is primarily used to smooth the voltage applied to the batteries or peripheral circuitry.

Automated optical inspection (AOI) can inspect the mounted condition of the components mounted on the circuit board in a short time using images of the circuit board collected in <NUM> or <NUM> dimensions, and is widely used due to its advantage, but cannot perfectly detect an open-circuit fault of the capacitor.

Further background art is described in <CIT> which describes a testing device that includes a signal sensing unit and a signal processing unit. The signal sensing unit generates a test output signal by sensing a signal from a device under test including a plurality of passive elements that are connected in parallel. The signal processing unit detects an open-type fault of the plurality of passive elements by measuring an impedance of the device under test based on element characteristic information of the plurality of passive elements.

The present disclosure is designed to solve the above-described problem, and therefore the present disclosure is directed to providing an apparatus and method for testing an open-circuit fault of a capacitor mounted on a circuit board included in a battery management system as defined in independent claims <NUM> and <NUM>.

These and other objects and advantages of the present disclosure may be understood by the following description and will be apparent from the embodiments of the present disclosure. Further, it will be readily understood that the objects and advantages of the present disclosure may be realized by the means set forth in the appended claims.

An apparatus according to an aspect of the present disclosure is for testing a circuit board of a battery management system. The circuit board includes a first resistor; a first capacitor; a second resistor; a second capacitor; a first test point connected in common to one end of the first resistor, one end of the first capacitor and one end of the second resistor; a second test point connected in common to the other end of the second resistor and one end of the second capacitor; a third test point connected to the other end of the first resistor; and a fourth test point connected in common to the other end of the first capacitor and the other end of the second capacitor. The apparatus includes a voltage source configured to selectively generate a test voltage, a first voltage sensor configured to detect a first diagnosis voltage generated between the first test point and the fourth test point, a second voltage sensor configured to detect a second diagnosis voltage generated between the second test point and the fourth test point, and a control unit operably coupled to the voltage source, the first voltage sensor and the second voltage sensor. The control unit is configured to command the voltage source to apply the test voltage onto the third test point. The control unit is configured to determine whether at least one of the first capacitor and the second capacitor has an open-circuit fault based on at least one of the first diagnosis voltage and the second diagnosis voltage. The control unit is configured to record a first time point when the first diagnosis voltage reaches a threshold voltage which is preset as being lower than the test voltage. The control unit is configured to determine that both the first capacitor and the second capacitor do not have the open-circuit fault, when a first elapsed period from an initial time point to the first time point is equal to or longer than a preset first threshold period. The initial time point is a time point when the test voltage starts to be applied onto the third test point.

The control unit may be configured to determine that only the second capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the first elapsed period is shorter than the first threshold period and is equal to or longer than a preset first monitoring period.

The control unit may be configured to determine that only the first capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the first elapsed period is shorter than the first monitoring period and is equal to or longer than a preset second monitoring period.

The control unit may be configured to determine that both the first capacitor and the second capacitor have the open-circuit fault, when the first elapsed period is shorter than the second monitoring period.

The control unit records a second time point when the second diagnosis voltage reaches the threshold voltage. The control unit is configured to determine that at least the second capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the first time point and the second time point are equal to each other. The control unit may record a second time point when the second diagnosis voltage reaches the threshold voltage. The control unit may be configured to determine that both the first capacitor and the second capacitor do not have the open-circuit fault, when a second elapsed period from the initial time point to the second time point is equal to or longer than a second threshold period which is preset as being longer than the first threshold period.

The control unit may be configured to output a diagnosis message indicating a result of the determination.

A method according to another aspect of the present disclosure is for testing a circuit board of a battery management system. The circuit board includes a first resistor; a first capacitor; a second resistor; a second capacitor; a first test point connected in common to one end of the first resistor, one end of the first capacitor and one end of the second resistor; a second test point connected in common to the other end of the second resistor and one end of the second capacitor; a third test point connected to the other end of the first resistor; and a fourth test point connected in common to the other end of the first capacitor and the other end of the second capacitor. The method includes commanding a voltage source to apply a test voltage onto the third test point, recording a time point when a first diagnosis voltage generated between the first test point and the fourth test point reaches a threshold voltage which is preset as being lower than the test voltage, and outputting a diagnosis message indicating that both the first capacitor and the second capacitor do not have an open-circuit fault, when an elapsed period from an initial time point to the recorded time point is equal to or longer than a preset first threshold period. The initial time point is a time point when the test voltage starts to be applied onto the third test point. The method further includes recording a second time point when a second diagnosis voltage generated between the second test point and the fourth test point reaches the threshold voltage and determining that at least the second capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the first time point and the second time point are equal to each other.

The method may further include outputting a diagnosis message indicating that only the second capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the elapsed period is shorter than the first threshold period and is equal to or longer than a preset first monitoring period. The method may further include outputting a diagnosis message indicating that only the first capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the elapsed period is shorter than the first monitoring period and is equal to or longer than a preset second monitoring period.

The method may further include outputting a diagnosis message indicating that both the first capacitor and the second capacitor have the open-circuit fault, when the elapsed period is shorter than the second monitoring period.

According to at least one of the embodiments of the present disclosure, it is possible to test an open-circuit fault of a capacitor mounted on a circuit board included in a battery management system without a process of capturing and analyzing an image of the circuit board.

Additionally, according to at least one of the embodiments of the present disclosure, it is possible to detect an open-circuit fault of at least one of two capacitors included in a second-order RC filter by applying a single test signal.

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

Prior to the description, it should be understood that the terms or words used in the specification and the appended claims should not be construed as being limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define the terms appropriately for the best explanation.

Therefore, the embodiments described herein and illustrations shown in the drawings are just a most preferred embodiment of the present disclosure, but not intended to fully describe the technical aspects of the present disclosure, so it should be understood that a variety of other equivalents and modifications could be made thereto at the time of filing the application.

Additionally, in describing the present disclosure, when it is deemed that a certain detailed description of relevant known elements or functions renders the key subject matter of the present disclosure ambiguous, the detailed description is omitted herein.

Unless the context clearly indicates otherwise, it will be understood that the term "comprises" or "includes" when used in this specification, specifies the presence of stated elements, but does not preclude the presence or addition of one or more other elements. Additionally, the term <control unit> as used herein refers to a processing unit of at least one function or operation, and this may be implemented by hardware or software alone or in combination.

<FIG> is an exemplary diagram showing configurations of a circuit board <NUM> included in a battery management system and an apparatus <NUM> for testing the circuit board <NUM> according to an embodiment of the present disclosure.

Referring to <FIG>, the circuit board <NUM> includes a first resistor <NUM>, a second resistor <NUM>, a first capacitor <NUM>, a second capacitor <NUM>, a first test point <NUM>, a second test point <NUM>, a third test point <NUM> and a fourth test point <NUM>. Each of the first resistor <NUM>, the second resistor <NUM>, the first capacitor <NUM>, the second capacitor <NUM>, the first test point <NUM>, the second test point <NUM>, the third test point <NUM> and the fourth test point <NUM> is mounted on the circuit board <NUM>, for example, by soldering, etc..

The first test point <NUM> is formed among the first resistor <NUM>, the first capacitor <NUM> and the second resistor <NUM>. In detail, one end of the first resistor <NUM>, one end of the first capacitor <NUM> and one end of the second resistor <NUM> are connected to the first test point <NUM> in common. The second test point <NUM> is formed between the second resistor <NUM> and the second capacitor <NUM>. In detail, the other end of the second resistor <NUM> and one end of the second capacitor <NUM> are connected to the second test point <NUM> in common.

The third test point <NUM> is connected to the other end of the first resistor <NUM>. The third test point <NUM> is a designated location on the circuit board <NUM> to which a test voltage is applied as a test signal used to detect an open-circuit fault of the first capacitor <NUM> and the second capacitor <NUM>.

The fourth test point <NUM> is formed between the other end of the first capacitor <NUM> and the other end of the second capacitor <NUM>. In detail, the other end of the first capacitor <NUM> and the other end of the second capacitor <NUM> are connected to the fourth test point <NUM> in common. The fourth test point <NUM> may be connected to the ground terminal of the circuit board <NUM>.

The first resistor <NUM>, the second resistor <NUM>, the first capacitor <NUM> and the second capacitor <NUM> that are electrically interconnected through the first test point <NUM>, the second test point <NUM>, the third test point <NUM> and the fourth test point <NUM> as described above may act as a second-order RC filter circuit. That is, the first resistor <NUM> and the first capacitor <NUM> may act as a first-order RC filter, the second resistor <NUM> and the second capacitor <NUM> may act as another first-order RC filter, and the two first-order RC filters may be connected through the first test point <NUM> to implement a second-order RC filter. The apparatus <NUM> includes a voltage source <NUM>, a first voltage sensor <NUM>, a second voltage sensor <NUM>, a control unit <NUM> and an information output unit <NUM>. Optionally, the apparatus <NUM> may further include a first test pin <NUM>, a second test pin <NUM>, a third test pin <NUM> and a fourth test pin <NUM>. The first test pin <NUM>, the second test pin <NUM>, the third test pin <NUM> and the fourth test pin <NUM> are arranged such that they may contact the first test point <NUM>, the second test point <NUM>, the third test point <NUM> and the fourth test point <NUM> at the same time respectively.

The voltage source <NUM> is configured to selectively generate the test voltage according to a command from the control unit <NUM>. The test voltage may be, for example, a pulse voltage. The voltage source <NUM> outputs the test voltage (for example, <NUM> V) in response to an ON command from the control unit <NUM>, and stops outputting the test voltage in response to an OFF command from the control unit <NUM>. The third test pin <NUM> is connected to the high potential terminal of the voltage source <NUM>, and the fourth test pin <NUM> may be connected to the low potential terminal of the voltage source <NUM>. When the test voltage is applied to the third test point <NUM> by the voltage source <NUM>, the current I<NUM> flowing from the third test point <NUM> to the first test point <NUM> branches into I<NUM> and I<NUM> at the first test point <NUM>. That is, the current I<NUM> is larger than the current I<NUM> and the current I<NUM>, and is equal to the sum of the current I<NUM> and the current I<NUM>.

One end of the first voltage sensor <NUM> may contact the first test point <NUM> directly or through the first test pin <NUM>, and the other end of the first voltage sensor <NUM> may contact the fourth test point <NUM> directly or through the fourth test pin <NUM>. The first voltage sensor <NUM> is configured to detect a first diagnosis voltage V<NUM> generated between the first test point <NUM> and the fourth test point <NUM>, and output a voltage signal indicating the detected first diagnosis voltage V<NUM> to the control unit <NUM>. One end of the second voltage sensor <NUM> may contact the second test point <NUM> directly or through the second test pin <NUM>, and the other end of the second voltage sensor <NUM> may contact the fourth test point <NUM> directly or through the fourth test pin <NUM>. The other end of the first voltage sensor <NUM> and the other end of the second voltage sensor <NUM> may be connected to the fourth test pin <NUM> in common. The second voltage sensor <NUM> is configured to detect a second diagnosis voltage V<NUM> generated between the second test point <NUM> and the fourth test point <NUM>, and output a voltage signal indicating the detected second diagnosis voltage V<NUM> to the control unit <NUM>.

The control unit <NUM> is operably coupled to the voltage source <NUM>, the first voltage sensor <NUM>, the second voltage sensor <NUM> and the information output unit <NUM>. The control unit <NUM> may communicate with each of the voltage source <NUM>, the first voltage sensor <NUM>, the second voltage sensor <NUM> and the information output unit <NUM> via a wired network such as Local Area Network (LAN), Controller Area Network (CAN) and daisy chain, or a local area wireless network such as Bluetooth, Zigbee and WiFi.

The control unit <NUM> may be, in hardware, implemented to include at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), microprocessors and electrical units for performing other functions. The control unit <NUM> may have a memory device embedded therein, and the memory device may be, for example, RAM, ROM, register, hard disk, an optical recording medium or a magnetic recording medium. The memory device may store, update and/or delete programs including various control logics that are executed by the control unit <NUM>, and/or data generated by the control logics when executed. The control unit <NUM> is configured to output the ON command to the voltage source <NUM> to induce the voltage source <NUM> to output the test voltage, and collect each of the voltage signal from the first voltage sensor <NUM> and the voltage signal from the second voltage sensor <NUM> from a time point (hereinafter referred to as 'initial time point') when the voltage source <NUM> started to output the test voltage in response to the ON command. The control unit <NUM> determines whether at least one of the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault based on at least one of the first diagnosis voltage V<NUM> indicated by the voltage signal from the first voltage sensor <NUM> and the second diagnosis voltage V<NUM> indicated by the voltage signal from the second voltage sensor <NUM>, then transmits a diagnosis message indicating the determination result to the information output unit <NUM>. That is, the diagnosis message may indicate that an open-circuit fault of either the first capacitor <NUM> or the second capacitor <NUM> or both occurred, or an open-circuit fault of both the first capacitor <NUM> and the second capacitor <NUM> did not occur.

The information output unit <NUM> may be implemented using a known device that outputs information visibly or audibly, such as, for example, a display and a speaker. The information output unit <NUM> is configured to output at least one of the visual information and the audible information corresponding to the diagnosis message transmitted by the control unit <NUM>.

The control unit <NUM> monitors changes in each of the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> over time while the test voltage is being applied onto the third test point <NUM> in real time by measuring the time elapsed from the initial time point.

<FIG> is a graph showing changes in the first diagnosis voltage V1 and the second diagnosis voltage V2 over time when an open-circuit fault did not occur in the first capacitor <NUM> and the second capacitor <NUM> included in the circuit board <NUM> of <FIG>. Referring to <FIG> and <FIG>, a curve <NUM> indicated as the solid line indicates changes in the first diagnosis voltage V<NUM>, and a curve <NUM> indicated as the dashed line indicates changes in the second diagnosis voltage V<NUM>. While the voltage source <NUM> is applying the test voltage VTEST onto the third test point <NUM>, the first capacitor <NUM> is gradually charged by the current I<NUM>, and the second capacitor <NUM> is gradually charged by the current I<NUM>.

Accordingly, each of the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> gradually increases from the initial time point T<NUM> when the voltage source <NUM> starts to apply the test voltage VTEST onto the third test point <NUM>. The first diagnosis voltage V<NUM> is equal to the sum of voltage generated across the second resistor <NUM> and the second diagnosis voltage V<NUM>. Accordingly, from the initial time point T<NUM> until the second diagnosis voltage V<NUM> equals the first diagnosis voltage V<NUM> (i.e., until I<NUM> = <NUM> A), the first diagnosis voltage V<NUM> is always higher than the second diagnosis voltage V<NUM>, and the second diagnosis voltage V<NUM> increases in pursuit of the first diagnosis voltage V<NUM>.

Referring to <FIG> and <FIG>, the control unit <NUM> records a time point T<NUM> when the first diagnosis voltage V<NUM> reaches a threshold voltage VTH, and records a time point T<NUM> when the second diagnosis voltage V<NUM> reaches the threshold voltage VTH. The threshold voltage VTH is preset as being higher than <NUM> V and lower than the test voltage VTEST. For example, when the test voltage VTEST is <NUM> V, the threshold voltage VTH may be <NUM> V that is <NUM>% of the test voltage VTEST. The control unit <NUM> may compare an elapsed period △T<NUM> from the initial time point T<NUM> to the time point T<NUM> with a preset first threshold period. Optionally, the control unit <NUM> may compare an elapsed period △T<NUM> from the initial time point T<NUM> to the time point T<NUM> with a preset second threshold period. As described above, because the second diagnosis voltage V<NUM> increases more slowly than the first diagnosis voltage V<NUM>, the second threshold period is preset as being longer than the first threshold period.

As shown in <FIG>, when the elapsed period △T<NUM> is equal to or longer than the first threshold period, or the elapsed period △T<NUM> is equal to or longer than the second threshold period, the control unit <NUM> may determine that the first capacitor <NUM> and the second capacitor <NUM> do not have an open-circuit fault, and output a first diagnosis message. The first diagnosis message indicates that neither the first capacitor <NUM> nor the second capacitor <NUM> has an open-circuit fault.

Hereinafter, resistance of the first resistor <NUM> is defined as R1, resistance of the second resistor <NUM> as R2, capacitance of the first capacitor <NUM> as C1, and capacitance of the second capacitor <NUM> as C2.

<FIG> is a graph showing changes in the first diagnosis voltage V1 and the second diagnosis voltage V2 over time when an open-circuit fault of only the second capacitor <NUM> occurred among the first capacitor <NUM> and the second capacitor <NUM> included in the circuit board <NUM> of <FIG>. Referring to <FIG> and <FIG>, a curve <NUM> indicates changes in the first diagnosis voltage V<NUM>. When the second capacitor <NUM> has an open-circuit fault, the current cannot flow through the second resistor <NUM> and the second capacitor <NUM> (i.e., I<NUM> = <NUM> A), and thus no voltage is generated across the second resistor <NUM>. That is, the first resistor <NUM>, the second resistor <NUM>, the first capacitor <NUM> and the second capacitor <NUM> shown in <FIG> cannot act as the second-order RC filter any longer, and act as a first-order RC filter including the first resistor <NUM> and the first capacitor <NUM>. In this case, the potential of the first test point <NUM> and the potential of the second test point <NUM> are kept equal, so the curve <NUM> also indicates changes in the second diagnosis voltage V<NUM>. That is, the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> increase according to the following Equation <NUM> from the initial time point T<NUM>.

In Equation <NUM>, τ<NUM> denotes the time constant of the first-order RC filter including the first resistor <NUM> and the first capacitor <NUM>, and is equal to R1 × C1.

Meanwhile, the current I<NUM> of 0A signifies that the current I<NUM> is equal to the current I<NUM>. Accordingly, when the second capacitor <NUM> has an open-circuit fault, the first capacitor <NUM> is charged faster than otherwise (see <FIG>), and thus, the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> increase rapidly toward the test voltage VTEST. As a result, the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> simultaneously reach the threshold voltage VTH at a time point T<NUM> that is earlier than the time point T<NUM>.

The control unit <NUM> may compare the elapsed period △T<NUM> from the initial time point T<NUM> to the time point T<NUM> with each of the first threshold period and a first monitoring period. The first monitoring period may be preset as being shorter than the first threshold period. As shown in <FIG>, when the elapsed period △T<NUM> is shorter than the first threshold period and is equal to or longer than the first monitoring period, the control unit <NUM> may determine that only the second capacitor <NUM> occurred among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault, and output a second diagnosis message. The second diagnosis message indicates that an open-circuit fault of the second capacitor <NUM> occurred.

Additionally, as shown in <FIG>, when the elapsed period △T<NUM> is shorter than the first threshold period and the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> reach the threshold voltage VTH at the same time point, the control unit <NUM> may determine that at least the second capacitor <NUM> among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault.

<FIG> is a graph showing changes in the first diagnosis voltage V1 and the second diagnosis voltage V2 over time when an open-circuit fault of only the first capacitor <NUM> occurred among the first capacitor <NUM> and the second capacitor <NUM> included in the circuit board <NUM> of <FIG>.

Referring to <FIG>, a curve <NUM> indicated as the solid line indicates changes in the first diagnosis voltage V<NUM>, and a curve <NUM> indicated as the dashed line indicates changes in the second diagnosis voltage V<NUM>. When the first capacitor <NUM> has an open-circuit fault, the current I<NUM> is <NUM> A, so the current I<NUM> is equal to the current I<NUM>. That is, the first resistor <NUM>, the second resistor <NUM>, the first capacitor <NUM> and the second capacitor <NUM> shown in <FIG> cannot act as the second-order RC filter any longer, and only act as a first-order RC filter including the first resistor <NUM>, the second resistor <NUM> and the second capacitor <NUM>. Accordingly, the first diagnosis voltage V<NUM> changes according to the following Equation <NUM>, and the second diagnosis voltage V<NUM> changes according to the following Equation <NUM>. <MAT> <MAT>.

In Equations <NUM> and <NUM>, τ<NUM> is the time constant of the first-order RC filter including the first resistor <NUM>, the second resistor <NUM> and the second capacitor <NUM>, and is equal to (R1 + R2) × C2. Those skilled in the art will easily understand that when τ<NUM> is smaller than τ<NUM>, the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> will increase toward the test voltage VTEST rapidly as shown in <FIG> compared to when only the second capacitor <NUM> has an open-circuit fault (see <FIG>). That is, a time point T<NUM> when the first diagnosis voltage V<NUM> reaches the threshold voltage VTH is earlier than a time point T<NUM> when the second diagnosis voltage V<NUM> reaches the threshold voltage VTH, and the time point T<NUM> is earlier than the time point T<NUM> of <FIG>.

The control unit <NUM> may compare the elapsed period △T<NUM> from the initial time point T<NUM> to the time point T<NUM> with each of the first monitoring period and a second monitoring period. The second monitoring period may be preset as being shorter than the first monitoring period. When the elapsed period △T<NUM> is shorter than the first monitoring period and is equal to or longer than the second monitoring period, the control unit <NUM> may determine that only the first capacitor <NUM> occurred among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault, and output a third diagnosis message. The third diagnosis message indicates that an open-circuit fault of the first capacitor <NUM> occurred.

<FIG> is a graph showing changes in the first diagnosis voltage V1 and the second diagnosis voltage V2 over time when both the first capacitor <NUM> and the second capacitor <NUM> included in the circuit board <NUM> of <FIG> have open-circuit fault.

Referring to <FIG>, a curve <NUM> indicates changes in the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM>. When both the first capacitor <NUM> and the second capacitor <NUM> have an open-circuit fault, the current can flow through none of the first resistor <NUM>, the second resistor <NUM>, the first capacitor <NUM> and the second capacitor <NUM> (i.e., I<NUM> = I<NUM> = <NUM> A), and thus no voltage is generated across the first resistor <NUM> and no voltage is generated across the second resistor <NUM>. Accordingly, the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> simultaneously reach the test voltage VTEST immediately after the initial time point T<NUM>.

When the elapsed period from the initial time point T<NUM> to the time point when at least one of the first diagnosis voltage V<NUM> and the second diagnosis voltage V<NUM> reaches the threshold voltage VTH or the test voltage VTEST is shorter than the second monitoring period, the control unit <NUM> may determine that both the first capacitor <NUM> and the second capacitor <NUM> have an open-circuit fault, and output a fourth diagnosis message. The fourth diagnosis message indicates that an open-circuit fault of both the first capacitor <NUM> and the second capacitor <NUM> occurred.

<FIG> is a flowchart showing a method for testing the circuit board <NUM> included in the battery management system according to another embodiment of the present disclosure. Referring to <FIG>, in step S600, the control unit <NUM> transmits the ON command to the voltage source <NUM>. In response to the ON command, the voltage source <NUM> applies the test voltage VTEST onto the third test point <NUM> from the initial time point.

In step S610, the control unit <NUM> determines the first diagnosis voltage V<NUM> based on the voltage signal from the first voltage sensor <NUM>.

In step S620, the control unit <NUM> determines the second diagnosis voltage V<NUM> based on the voltage signal from the second voltage sensor <NUM>.

In step S630, the control unit <NUM> determines whether the first diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S630 is "YES", the control unit <NUM> records the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH and then may perform step S640. When the value of the step S630 is "NO", the method may revert to the step S610.

In step S640, the control unit <NUM> determines whether the elapsed period from the initial time point to the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH is equal to or longer than the first threshold period. When a value of the step S640 is "YES", step S670 may be performed. When the value of the step S640 is "NO", step S680 may be performed.

In step S650, the control unit <NUM> determines whether the second diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S650 is "YES", the control unit <NUM> records the time point when the second diagnosis voltage V<NUM> reached the threshold voltage VTH, and then may perform step S660. When the value of the step S650 is "NO", the method may revert to the step S610. In step S660, the control unit <NUM> determines whether the elapsed period from the initial time point to the time point when the second diagnosis voltage V<NUM> reached the threshold voltage VTH is equal to or longer than the second threshold period. When a value of the step S660 is "YES", step S670 may be performed. When the value of the step S660 is "NO", step S680 may be performed.

In step S670, the control unit <NUM> outputs a diagnosis message indicating that both the first capacitor <NUM> and the second capacitor <NUM> do not have an open-circuit fault.

In step S680, the control unit <NUM> outputs a diagnosis message indicating that at least one of the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault.

<FIG> is a flowchart showing a method for testing the circuit board <NUM> included in the battery management system according to still another embodiment of the present disclosure.

Referring to <FIG> and <FIG>, in step S700, the control unit <NUM> transmits the ON command to the voltage source <NUM>. In response to the ON command, the voltage source <NUM> applies the test voltage VTEST onto the third test point <NUM> from the initial time point.

In step S710, the control unit <NUM> determines the first diagnosis voltage V<NUM> based on the voltage signal from the first voltage sensor <NUM>.

In step S720, the control unit <NUM> determines whether the first diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S720 is "YES", the control unit <NUM> records the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH, and then may perform step S730. When the value of the step S720 is "NO", the method may revert to the step S710. In step S730, the control unit <NUM> determines whether the elapsed period from the initial time point to the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH is shorter than the first threshold period and is equal to or longer than the first monitoring period. When a value of the step S730 is "YES", step S740 may be performed. When the value of the step S730 is "NO", step S750 may be performed.

In step S740, the control unit <NUM> outputs a diagnosis message indicating that only the second capacitor <NUM> among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault.

In step S750, the control unit <NUM> determines whether the elapsed period from the initial time point to the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH is shorter than the first monitoring period and is equal to or longer than the second monitoring period. When a value of the step S750 is "YES", step S760 may be performed. When the value of the step S750 is "NO", step S770 may be performed.

In step S760, the control unit <NUM> outputs a diagnosis message indicating that only the first capacitor <NUM> among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault.

In step S770, the control unit <NUM> determines whether the elapsed period from the initial time point to the time point when the second diagnosis voltage V<NUM> reached the threshold voltage VTH is shorter than the second monitoring period. When a value of the step S770 is "YES", step S780 may be performed.

In step S780, the control unit <NUM> outputs a diagnosis message indicating that both the first capacitor <NUM> and the second capacitor <NUM> have an open-circuit fault.

<FIG> is a flowchart showing a method for testing the circuit board <NUM> included in the battery management system according to yet another embodiment of the present disclosure. Referring to <FIG> and <FIG>, in step S800, the control unit <NUM> transmits the ON command to the voltage source <NUM>. In response to the ON command, the voltage source <NUM> applies the test voltage VTEST onto the third test point <NUM> from the initial time point.

In step S810, the control unit <NUM> determines the first diagnosis voltage V<NUM> based on the voltage signal from the first voltage sensor <NUM>.

In step S820, the control unit <NUM> determines the second diagnosis voltage V<NUM> based on the voltage signal from the second voltage sensor <NUM>.

In step S830, the control unit <NUM> determines whether the first diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S830 is "YES", the control unit <NUM> records the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH, and then may perform step S850. When the value of the step S830 is "NO", the method may revert to the step S810.

In step S840, the control unit <NUM> determines whether the second diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S840 is "YES", the control unit <NUM> records the time point when the second diagnosis voltage V<NUM> reached the threshold voltage VTH, and then may perform step S850. When the value of the step S840 is "NO", the method may revert to the step S820.

In step S850, the control unit <NUM> determines whether the time point when the first diagnosis voltage V<NUM> reached the threshold voltage VTH is equal to the time point when the second diagnosis voltage V<NUM> reached the threshold voltage VTH. When a value of the step S850 is "YES", step S860 may be performed.

In step S860, the control unit <NUM> outputs a diagnosis message indicating that at least the second capacitor <NUM> among the first capacitor <NUM> and the second capacitor <NUM> has an open-circuit fault. According to the present disclosure described above, it is possible to test an open-circuit fault of each of the two capacitors <NUM>, <NUM> mounted on the circuit board <NUM> without a process of capturing and analyzing an image of the circuit board <NUM> included in the battery management system. Additionally, it is possible to detect an open-circuit fault of at least one of the two capacitors <NUM>, <NUM> included in the second-order RC filter by applying a single test signal (i.e., test voltage).

The embodiments of the present disclosure described hereinabove are not implemented only through the apparatus and method, and may be implemented through programs that realize the functions corresponding to the configurations of the embodiments of the present disclosure or recording media having the programs recorded thereon, and this implementation may be easily achieved by those skilled in the art from the disclosure of the embodiments previously described.

While the present disclosure has been hereinabove described with regard to a limited number of embodiments and drawings, the present disclosure is not limited thereto and it is obvious to those skilled in the art that various modifications and changes may be made thereto within the technical aspects of the present disclosure.

Additionally, as many substitutions, modifications and changes may be made to the present disclosure described hereinabove by those skilled in the art without departing from the technical aspects of the present disclosure, the present disclosure is not limited by the above-described embodiments and the accompanying drawings, and some or all of the embodiments may be selectively combined to allow various modifications.

Claim 1:
An apparatus (<NUM>) for testing a circuit board (<NUM>) of a battery management system, wherein the circuit board includes a first resistor (<NUM>); a first capacitor (<NUM>); a second resistor (<NUM>); a second capacitor (<NUM>); a first test point (<NUM>) connected in common to one end of the first resistor, one end of the first capacitor and one end of the second resistor; a second test point (<NUM>) connected in common to the other end of the second resistor and one end of the second capacitor; a third test point (<NUM>) connected to the other end of the first resistor; and a fourth test point (<NUM>) connected in common to the other end of the first capacitor and the other end of the second capacitor, the apparatus comprising:
a voltage source (<NUM>);
a first voltage sensor (<NUM>) configured to detect a first diagnosis voltage generated between the first test point and the fourth test point; and
a second voltage sensor (<NUM>) configured to detect a second diagnosis voltage generated between the second test point and the fourth test point; and
a control unit (<NUM>) operably coupled to the voltage source, the first voltage sensor and the second voltage sensor and configured to control the voltage source to apply a test voltage onto the third test point, and record a first time point at which the first diagnosis voltage reaches a threshold voltage which is preset as being lower than the test voltage, and record a second time point when the second diagnosis voltage reaches the threshold voltage,
to determine that both the first capacitor and the second capacitor do not have an open-circuit fault in response to a first elapsed period from an initial time point to the first time point being equal to or longer than a preset first threshold period, wherein the initial time point is a time point when the test voltage starts to be applied onto the third test point, and
to determine that at least the second capacitor among the first capacitor and the second capacitor has the open-circuit fault, when the first time point and the second time point are equal to each other.