Battery Apparatus, Battery Management System, and Method for Diagnosing Connection Status

In a battery apparatus, a battery pack includes a plurality of battery modules and a bus-bar connecting two battery modules among the plurality of battery modules. A wire connects the battery pack and the switch for controlling current supply of the battery pack. A voltage measuring circuit measures a voltage of the bus-bar, a voltage of the battery pack, and voltages of the plurality of battery modules. A processor diagnoses a connection status of the bus-bar and a connection status of the wire based on a current of the battery pack, the voltage of the bus-bar, the voltage of the battery pack, and the voltages of the plurality of battery modules.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0131092 filed in the Korean Intellectual Property Office on Oct. 12, 2020, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The described technology relates to a battery apparatus, a battery management system, and a method for diagnosing a connection status.

BACKGROUND ART

An electric vehicle or a hybrid vehicle is a vehicle that obtains power by driving a motor mainly using a battery as a power supply. The electric vehicles are being actively researched because they are alternatives that can solve pollution and energy problems of internal combustion vehicles. Rechargeable batteries are used in various external apparatuses other than the electric vehicles.

Recently, as a battery having a high output and a large charging capacity is required, a battery pack in which a plurality of battery modules are connected in series is used. Two adjacent battery modules in the battery pack are connected to each other via a bus-bar. An output terminal of the battery pack is connected via a wire to a switch that controls supply of a current to the battery pack.

Accordingly, when a problem occurs in the connection of the bus-bar or a problem occurs in the wire for connecting the battery pack and an external apparatus, power cannot be supplied through the battery pack.

DISCLOSURE

Technical Problem

Some embodiments may provide a battery apparatus, a battery management system, and a method for diagnosing a connection status, for diagnosing a problem related to a connection status of the battery apparatus.

Technical Solution

According to an embodiment, a battery apparatus including a battery pack, a switch, a wire, a voltage measuring circuit, and a processor may be provided. The battery pack may include a plurality of battery modules and a bus-bar connecting two battery modules among the plurality of battery modules. The switch may control current supply of the battery pack, and the wire may connect the battery pack and the switch. The voltage measuring circuit may measure a voltage of the bus-bar, a voltage of the battery pack, and voltages of the plurality of battery modules. The processor may diagnose a connection status of the bus-bar and a connection status of the wire based on a current of the battery pack, the voltage of the bus-bar, the voltage of the battery pack, and the voltages of the plurality of battery modules.

In some embodiments, the processor may calculate a resistance of the bus-bar based on the voltage of the bus-bar and the current of the battery pack, and diagnose the connection status of the bus-bar based on the resistance of the bus-bar.

In some embodiments, in response to the resistance of the bus-bar being greater than a threshold, the processor may diagnose that an error has occurred in the connection status of the bus-bar.

In some embodiments, the processor may determine the voltage of the bus-bar based on a voltage between a node at which the bus-bar is connected to one of the two battery modules and a node at which the bus-bar is connected to the other one of the two battery modules.

In some embodiments, the processor may determine a voltage across the wire based on the voltage of the bus-bar, the voltage of the battery pack, and the voltages of the plurality of battery modules, calculate a resistance of the wire based on the voltage across the wire and the current of the battery pack, and diagnose the connection status of the wire based on the resistance of the wire.

In some embodiments, in response to the resistance of the wire being greater than a threshold, the processor may diagnose that an error has occurred in the connection status of the wire.

In some embodiments, the switch may include a first switch and a second switch, and the wire may include a first wire connecting a positive terminal of the battery pack and the first switch, and a second wire connecting a negative terminal of the battery pack and the second switch. In this case, the voltage across the wire may include a voltage across the first wire and a voltage across the second wire.

In some embodiments, the voltage measuring circuit may measure the voltage of the battery pack based on a voltage between a first node to which the first wire is connected to the first switch and a second node to which the second wire is connected to the second switch.

In some embodiments, the processor may determine the voltage across the wire based on a value obtained by subtracting a sum of the voltages of the plurality of battery modules and the voltage of the bus-bar from the voltage of the battery pack.

In some embodiments, the bus-bar may include a plurality of bus-bars, and each of the bus-bars may connect corresponding two battery modules among the plurality of battery modules. In this case, the processor may determine the voltage across the wire based on a value obtained by subtracting a sum of the voltages of the plurality of battery modules and a sum of voltages of the plurality of bus-bars from the voltage of the battery pack.

According to another embodiment, a method of diagnosing a connection status of a battery pack including a plurality of battery modules may be provided. The method may include measuring a current of the battery pack, measuring a voltage of the battery pack, measuring a voltage of each of the plurality of battery modules, measuring a voltage of a bus-bar connecting two battery modules among the plurality of battery modules, and diagnosing a connection status of the bus-bar and a connection status of a wire connected to the battery pack, based on the current of the battery pack, the voltage of the bus-bar, the voltage of the battery pack, and voltages of the plurality of battery modules.

In some embodiments, the diagnosing the connection status may include calculating a resistance of the bus-bar based on the voltage of the bus-bar and the current of the battery pack, and diagnosing the connection status of the bus-bar based on the resistance of the bus-bar.

In some embodiments, the diagnosing the connection status may include determining a voltage across the wire based on the voltage of the bus-bar, the voltage of the battery pack, and the voltage of the plurality of battery modules, calculating a resistance of the wire based on the voltage across the wire and the current of the battery pack, and diagnosing the connection status of the wire based on the resistance of the wire.

In some embodiments, the wire may include a first wire connecting a positive terminal of the battery pack and a first switch for controlling current supply of the battery pack, and a second wire connecting a negative terminal of the battery pack and a second switch for controlling current supply of the battery pack. In this case, the measuring the voltage of the battery pack may include measuring the voltage of the battery pack based on a voltage between a first node to which the first wire is connected to the first switch and a second node to which the second wire is connected to the second switch.

According to yet another embodiment, a battery management system of a battery apparatus including a battery pack, a switch for controlling current supply of the battery pack, and a wire connecting the battery pack and the switch may be provided. The battery pack may include a plurality of battery modules and a bus-bar connecting two battery modules among the plurality of battery modules. The battery management system may include a voltage measuring circuit configured to measure a voltage of the bus-bar, a voltage of the battery pack, and voltages of the plurality of battery modules, and a processor configured to diagnose a connection status of the bus-bar and a connection status of the wire based on a current of the battery pack, the voltage of the bus-bar, the voltage of the battery pack, and the voltages of the plurality of battery modules.

Advantageous Effects

According to some embodiments, a connection state of a bus-bar and a wire may be diagnosed in the battery apparatus.

MODE FOR INVENTION

When it is described that an element is “connected” to another element, it should be understood that the element may be directly connected to the other element or connected to the other element through a third element. On the other hand, when it is described that an element is “directly connected” to another element, it should be understood that the element is connected to the other element through no third element.

As used herein, a singular form may be intended to include a plural form as well, unless the explicit expression such as “one” or “single” is used.

In flowcharts described with reference to the drawings, the order of operations or steps may be changed, several operations or steps may be merged, a certain operation or step may be divided, and a specific operation or step may not be performed.

FIG.1is a diagram showing a battery apparatus according to an embodiment.

Referring toFIG.1, a battery apparatus100has a structure that can be electrically connected to an external apparatus through a positive link terminal DC(+) and a negative link terminal DC(−). In some embodiments, the battery apparatus100may be connected to the external apparatus10through the positive link terminal DC(+) and the negative link terminal DC(−). When the external apparatus is a load, the battery apparatus100is discharged by operating as a power supply that supplies power to the load. The external apparatus operating as the load may be, for example, an electronic device, a mobility apparatus, or an energy storage system (ESS). The mobility apparatus may be, for example, a vehicle such as an electric vehicle, a hybrid vehicle, or a smart mobility.

The battery apparatus100includes a battery pack110, a positive main switch121, a negative main switch122, a voltage measuring circuit130, a current sensor140, and a processor150.

The battery pack110has a positive terminal PV(+) and a negative terminal PV(−). The battery pack includes a plurality of battery modules (not shown) connected in series between the positive terminal PV(+) and the negative terminal PV(−), and each battery module includes a plurality of battery cells (not shown) connected in series. In some embodiments, the battery cell may be a rechargeable cell. In this way, the plurality of battery modules may be connected in the battery pack110to supply desired power.

The positive main switch121is connected between the positive terminal PV(+) of the battery pack110and the positive link terminal DC(+) of the battery apparatus100. The negative main switch122is connected between the negative terminal PV(−) of the battery pack110and the negative link terminal DC(−) of the battery apparatus100. The switches121and122may be controlled by the processor140to control an electrical connection between the battery pack110and the external apparatus. That is, the switches121and122may control supply of a current of the battery pack110. In one embodiment, each of the switches121and122may be a contactor implemented in a relay. In another embodiment, each of the switches121and122may be an electrical switch such as a transistor. In some embodiments, the battery apparatus100may further include driving circuits (not shown) for controlling the switches121and122, respectively.

The voltage measuring circuit130measures a voltage at a predetermined point in the battery apparatus100. The current sensor140measures the current of the battery pack110. In some embodiments, the current sensor140may measure a discharge current of the battery pack110(e.g., a current flowing from the positive terminal PV(+) of the battery pack110to the positive link terminal DC(+)) or a charging current of the battery pack110(e.g., a current flowing from the positive link terminal DC(+) to the positive terminal PV(+) of the battery pack110). Although the current sensor140is shown as being connected between the positive terminal PV(+) and the positive link terminal DC(+) of the battery pack inFIG.1, a position of the current sensor140is not limited thereto. For example, the current sensor140may be connected between the negative terminal PV(−) of the battery pack and the negative link terminal DC(−). In some embodiments, the current sensor140may be included in the battery pack110.

The processor150diagnoses a connection status of the battery apparatus100based on the voltage measured by the voltage measuring circuit130and the current measured by the current sensor140. In some embodiments, the processor150may control operations of the switches121and122. The processor150may be, for example, a micro controller unit (MCU).

The processor150may form a battery management system. In some embodiments, the battery management system may further include the voltage measuring circuit130or the current sensor140.

FIG.2is a diagram for explaining voltage measurement of a battery apparatus according to an embodiment, andFIG.3is a diagram showing an example of a bus-bar in a battery apparatus according to an embodiment.

Referring toFIG.2, a plurality of battery modules211,212,213, and214are connected in series in a battery pack210. Although four battery modules211,212,213, and214are shown inFIG.2for convenience of description, the number of battery modules is not limited thereto.

Two adjacent battery modules are connected via a bus-bar. A bus-bar221connects the battery module211and the battery module212, a bus-bar222connects the battery module212and the battery module213, and a bus-bar223connects the battery module213and the battery module214. A first terminal of the bus-bar221may be connected to a node BBP1corresponding to a negative terminal of the battery module211, and a second terminal of the bus-bar221may be connected to a node BBN1corresponding to a positive terminal of the battery module212. Further, a first terminal of the bus-bar222may be connected to a node BBP2corresponding to a negative terminal of the battery module212, and a second terminal of the bus-bar222may be connected to a node BBN2corresponding to a positive terminal of the battery module213. Furthermore, a first terminal of the bus-bar223may be connected to a node BBP3corresponding to a negative terminal of the battery module213, and a second terminal of the bus-bar223may be connected to a node BBN3corresponding to a positive terminal of the battery module214. In some embodiments, the positive terminal of each battery module may be connected to a positive electrode of the first battery cell among a plurality of battery cells, which are included in the corresponding battery module and are connected in series, and the negative terminal of each battery module may be connected to a negative electrode of the last battery cell among the plurality of battery cells, which are included in the corresponding battery module and are connected in series.

In some embodiments, the bus-bars221,222, and223may be formed of a material having electrical conductivity. The bus-bars221,222, and223may be formed in various shapes according to a structure of the battery pack210or the battery modules211,212,213and214. For example, as shown inFIG.3, the bus-bar221may be connected with an electrode terminal211aof one battery module211and an electrode terminal212aof the other battery module212so as to connect the battery module211and the battery module212. The electrode terminal211aof the battery module211may be a negative terminal of the battery module211, and the electrode terminal212aof the battery module212may be a positive terminal of the battery module212. As described above, since the bus-bar221is used for connecting the two battery modules, a current supplied from the battery apparatus may be interrupted when the connection is broken due to a defect in the connection status of the bus-bar.

The positive terminal PV(+) of the battery pack210is connected to a positive main switch241through a wire231, and the negative terminal PV(−) of the battery pack210is connected to a negative main switch242through a wire232. In this case, the wire231may be connected to the positive main switch241at a node W1, and the wire232may be connected to the negative main switch242at a node W2. In some embodiments, the positive terminal PV(+) of the battery pack210may correspond to a positive terminal of the first battery module211among the plurality of battery modules211,212,213, and214included in the battery pack210, and the negative terminal PV(−) of the battery pack210may correspond to a negative terminal of the last battery module214among the plurality of battery modules211,212,213and214included in the battery pack210. In some embodiments, the wires231and232may be provided as a wire harness.

When the positive main switch241and the negative main switch242are closed, a current Ipackflows through the battery pack210. That is, the current Ipackflows through the plurality of battery modules211,212,213, and214. In this case, a voltage measuring circuit250measures voltages of the bus-bars221,222, and223. The voltage measuring circuit250may measure a voltage between the first terminal and the second terminal of each bus-bar as the voltage of the corresponding bus-bar. That is, the voltage measuring circuit250may measure a voltage between the both terminals of the bus-bar221, i.e., a voltage between the two nodes BBP1and BBN1, as a voltage of the bus-bar221, measure a voltage between the both terminals of the bus-bar222, i.e., a voltage between the two nodes BBP2and BBN2, as a voltage of the bus-bar222, and measure a voltage between the both terminals of the bus-bar223, i.e., a voltage between the two nodes BBP3and BBN3, as a voltage of the bus-bar223.

In some embodiments, the voltage measuring circuit250may include a cell voltage monitoring integrated circuit (IC). In some embodiments, a plurality of cell voltage monitoring ICs respectively corresponding to a plurality of battery modules may be provided. In some embodiments, one cell voltage monitoring IC may correspond to at least two battery modules among the plurality of battery modules. In some embodiments, one of the plurality of battery modules may correspond to two cell voltage monitoring ICs. In this case, one of the cell voltage monitoring ICs may correspond to some battery cells of the corresponding battery module, and the other one of the cell voltage monitoring ICs may correspond to the remaining battery cells of the corresponding battery module.

In some embodiments, the cell voltage monitoring IC may include a plurality of pins respectively connected to a plurality of battery cells of the battery module and two pins respectively connected to both terminals of the bus-bar. In this case, the cell voltage monitoring IC may measure the voltage of the bus-bar through the two pins respectively connected to both terminals of the bus-bar. Further, the cell voltage monitoring IC may measure a voltage of the battery cell through pins connected to the positive and negative electrodes of the battery cell.

The processor (e.g.,150inFIG.1) may diagnose connection statuses of the bus-bars221,222, and223based on the voltages measured by the voltage measuring circuit250.

Next, a method of diagnosing a connection status in a battery apparatus according to various embodiments is described with reference toFIG.4andFIG.5.

FIG.4is a flowchart showing a method for diagnosing a connection status in a battery apparatus according to an embodiment.

Referring toFIG.4, a processor (e.g.,150inFIG.1) of a battery management system closes a positive main switch (e.g.,141inFIG.2) and a negative main switch (e.g.,FIG.142inFIG.2). Then, a current flows through the battery pack (e.g.,210inFIG.2). Accordingly, the processor150receives a current of the battery pack measured by a current sensor at S410.

Further, a voltage measuring circuit250measures a voltage of a bus-bar (e.g.,221,222, or223inFIG.2) connecting adjacent battery modules at S420. In some embodiments, the voltage measuring circuit250may measure a voltage between both terminals of the bus-bar221,222, or223as the voltage of the bus-bar221,222, or223. The processor150receives the voltages of the bus-bars221,222, and223from the voltage measuring circuit250at S420.

Next, the processor150calculates a resistance of each of the bus-bars221,222, and223based on the current of the battery pack210and the voltage of each of the bus-bars221,222, and223at S430. In some embodiments, as shown inFIG.2, since the current of the battery pack210flows through the bus-bars221,222, and223, the voltage measuring circuit250may determine, as the resistance of each of the bus-bars221,222, and223, a value obtained by dividing the voltage of each of the bus-bars221,222, and223by the current of the battery pack210, as in Equation 1.

In Equation 1, Rbusbardenotes the resistance of the busbar, Vbusbardenotes the voltage of the busbar, and Ipackdenotes the current of the battery pack.

The processor150diagnoses a connection status of the battery apparatus based on the resistance of each bus-bar and a resistance of a wire at S440. In some embodiments, the processor150may determine whether the resistance of each bus-bar is greater than a threshold, and if there is a bus-bar having the resistance greater than the threshold, the processor150may diagnose that an error has occurred in the connection status of the corresponding bus-bar. In some embodiments, when diagnosing that the error has occurred in the connection status of the bus-bar, the processor150may transmit an error signal to an external apparatus (e.g., a vehicle). Accordingly, a user (e.g., a driver) of the external apparatus may check the error and perform an action corresponding to the error.

On the other hand, as shown inFIG.2, in the battery pack210, an error may occur not only in the connection of the bus-bar, but also in a connection status of wires231and232connecting the battery pack210and the main switches241and242. Accordingly, it may not be possible to accurately diagnose the connection status of the battery apparatus only by diagnosing the connection status of the bus-bar.

FIG.5is a flowchart showing a method for diagnosing a connection status in a battery apparatus according to another embodiment.

Referring toFIG.5, a processor (e.g.,150inFIG.1) of the battery management system closes a positive main switch (e.g.,141inFIG.2) and a negative switch (e.g.,FIG.142inFIG.2). Then, a current flows through a battery pack (e.g.,210inFIG.2). Accordingly, the processor150receives a current of the battery pack measured by a current sensor at S510.

Further, a voltage measuring circuit (e.g.,250inFIG.2) measures a voltage of a bus-bar (e.g.,221,222, or223inFIG.2) connecting adjacent battery modules. In some embodiments, the voltage measuring circuit250may measure a voltage between both terminals of the bus-bar221,222, or223as the voltage of the bus-bar221,222, or223. The processor150receives the voltages of the bus-bars221,222, and223from the voltage measuring circuit250at S520.

Furthermore, the voltage measuring circuit250measures a voltage of the battery pack210and voltages of battery modules (e.g.,211,212,213, and214inFIG.2) at S520. In some embodiments, the voltage measuring circuit250may measure the voltage of the battery pack210by measuring voltages of nodes at which wires (e.g.,231and232inFIG.2) of the battery pack210are connected to the main switches (e.g.,241and242inFIG.2). In some embodiments, the voltage measuring circuit250may measure a voltage between a positive terminal and a negative terminal of each battery module as the voltage of the corresponding battery module. In some embodiments, the voltage measuring circuit250may measure the voltage of each battery module as a sum of voltages of a plurality of battery cells included in the corresponding battery module. The processor150receives the voltage of the battery pack210and the voltages of the battery modules from the voltage measuring circuit250at S520.

The processor150calculates a resistance of each of the bus-bars221,222, and223based on the current of the battery pack210and the voltage of each of the bus-bars221,222, and223at S530. In some embodiments, the processor150may calculate the resistance of each of the bus-bars221,222, and223as described with reference to S430ofFIG.4.

Further, the processor150calculates a voltage across the wires231and232based on the current of the battery pack210, the voltage of the battery pack210, and the voltages of the battery modules211,212,213and214at S540. In some embodiments, the voltage measuring circuit250may measure the voltage of the battery pack210by measuring a voltage of a node (e.g., W1inFIG.2) at which the wire231is connected to the positive main switch241and a voltage of a node (e.g., W2inFIG.2) at which the wire232is connected to the negative main switch242. That is, the voltage measuring circuit250may measure a voltage between the two nodes W1and W2as the voltage of the battery pack210. In some embodiments, as shown inFIG.2, the voltage of the battery pack210, i.e., the voltage between the two nodes W1and W2is formed by the voltage across the wires231and232, the voltages of the battery module211,212,213, and214, and the voltages of the bus-bars221,222, and223, the processor150may determine, as the voltage across the two wires231and232, a value obtained by subtracting the voltages of the battery modules211,212,213, and214, and the voltages of the bus-bars221,222, and223from the voltage of the battery pack210, as in Equation 2.

In Equation 2, Vwiredenotes the voltage across the two wires, Vpackdenotes the voltage of the battery pack, Vmodule(i) denotes the voltage of the i-th battery module, N denotes the number of battery modules included in the battery pack, Vbusbar(i) denotes the voltage of the i-th bus-bar, and M denotes the number of bus-bars included in the battery pack. In some embodiments, M may be equal to (N−1).

Furthermore, the processor150calculates a resistance of the wires231and232based on the current of the battery pack210and the voltage across the wires231and232at S550. In some embodiments, since the current of the battery pack210flows through the wires231and232as shown inFIG.2, the voltage measuring circuit250may determine, as the resistance of the two wires231and232, a value obtained by dividing the voltage across the wires231and232by the current of the battery pack210.

In Equation 3, Rwiredenotes the resistance of the two wires, Vwiredenotes the voltage across the two wires, and Ipackdenotes the current of the battery pack.

The processor150diagnoses a connection status of the battery apparatus based on the resistance of each bus-bar and the resistance of the wires at S560. In some embodiments, the processor150may determine whether the resistance of each bus-bar is greater than a threshold, and if there is a bus-bar having the resistance greater than the threshold, the processor150may diagnose that an error has occurred in the connection status of the corresponding bus-bar. Further, the processor150may determine whether the resistance of the wires is greater than a threshold, and if the resistance of the wires is greater than the threshold value, the processor150may diagnose that an error has occurred in the connection status of the wires. In some embodiments, when diagnosing that the error has occurred in the connection status of the bus-bar or wires, the processor150may transmit an error signal to an external apparatus (e.g., a vehicle). Accordingly, a user (e.g., a driver) of the external apparatus may check the error and perform an action corresponding to the error.

According to the above-described embodiments, not only the connection status of the bus-bar but also the connection status of the wires connecting the battery pack to the main switches can be diagnosed, so that the connection status of the battery apparatus can be accurately diagnosed.