Battery management system, battery device and method for diagnosing cell voltage sensing line

Abstract

A battery management system is provided in which a battery monitoring circuit is connected to a battery cell via a cell voltage sensing line; measuring a voltage of the battery cell as a first voltage through a cell voltage sensing line in a state in which cell balance of the battery cell is disabled; and measuring a voltage of the battery cell as a second voltage through the cell voltage sensing line in a state in which cell balancing of the battery cell is enabled. The processor diagnoses the battery voltage sense line based on a difference between the first voltage and the second voltage and the first voltage.

Description

TECHNICAL FIELD

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0054637, filed on April 24, 2024, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a battery management system, a battery apparatus, and a method of diagnosing a cell voltage sensing line. BACKGROUND

[0004] An electric vehicle or a hybrid vehicle is a vehicle that obtains power by driving a motor mainly using a battery as a power source. Electric vehicles are being actively researched because they are an alternative solution that can solve the pollution and energy problems of internal combustion vehicles. In addition, batteries are also used in various external devices other than electric vehicles.

[0005] As the maximum power required by external devices increases, the use of multiple battery cells is required, and thus, in order to accurately diagnose or control the battery cells, the voltage of the battery cells (hereinafter referred to as "cell voltage") needs to be accurately measured. A cell voltage sensing line is used to measure the cell voltage. If the cell voltage sensing line fails, the cell voltage cannot be accurately measured.

[0006] If the difference between the cell voltage measured when no balancing current flows and the cell voltage measured when a balancing current flows is greater than or equal to a preset voltage, it can be diagnosed that there is a problem with the cell voltage sensing line. However, when the cell voltage is low, the balancing current is small, resulting in a small difference in voltage between the two. Therefore, this method can only diagnose the cell voltage sensing line when the cell voltage is high, and can not be able to diagnose the cell voltage sensing line when the cell voltage is low. SUMMARY

[0007] TECHNICAL PROBLEM

[0008] Some embodiments can provide a battery management system, a battery apparatus, and a method of diagnosing a cell voltage sensing line, which can accurately diagnose the cell voltage sensing line.

[0009] TECHNICAL SOLUTION

[0010] According to some embodiments, a battery management system configured to manage a battery cell can be provided. The battery management system can include a battery monitoring circuit connected to the battery cell via a cell voltage sense line and configured to measure a voltage of the battery cell as a first voltage via the cell voltage sense line when a cell balancing of the battery cell is disabled and measure a voltage of the battery cell as a second voltage via the cell voltage sense line when the cell balancing of the battery cell is enabled, and a processor configured to diagnose the cell voltage sense line based on a difference between the first voltage and the second voltage and the first voltage.

[0011] A battery apparatus according to some embodiments can include a battery cell, a first cell voltage sense line connected to a positive electrode of the battery cell, a second cell voltage sense line connected to a negative electrode of the battery cell, a first resistor connected between the first cell voltage sense line and a first cell balancing terminal, a switch connected between the first cell balancing terminal and a second cell balancing terminal to which the second cell voltage sense line is connected, and a processor configured to diagnose the first cell voltage sense line or the second cell voltage sense line based on a difference between a first voltage and a second voltage and the first voltage, the first voltage being a voltage between the first cell voltage sense line and the second cell voltage sense line measured when the switch is turned off, and the second voltage being a voltage between the first cell voltage sense line and the second cell voltage sense line measured when the switch is turned on.

[0012] According to some embodiments, a method of diagnosing a cell voltage sense line connected to a battery cell in a battery management system can be provided. The method can include measuring a voltage of the battery cell as a first voltage via the cell voltage sense line when a cell balancing of the battery cell is disabled, measuring a voltage of the battery cell as a second voltage via the cell voltage sense line when the cell balancing of the battery cell is enabled, and diagnosing the cell voltage sense line based on a difference between the first voltage and the second voltage and the first voltage. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 FIG. 1 is a diagram illustrating a battery apparatus according to some embodiments.

[0014] Figure 2 and Figure 3 FIG. 2 is a diagram illustrating a method of diagnosing a cell voltage sense line according to some embodiments.

[0015] Figure 4is a flowchart illustrating a method of diagnosing a cell voltage sensing line according to some embodiments. DETAILED DESCRIPTION

[0016] In the following detailed description, certain embodiments of the application are shown and described by way of illustration. As those skilled in the art will appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the application. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements in the drawings and description throughout the specification.

[0017] When an element is "connected" to another element, it should be understood that the element can be directly connected to the other element or connected to the other element with a third element interposed therebetween. On the other hand, when an element is "directly connected" to another element, it should be understood that the element is not connected to the other element with a third element interposed therebetween.

[0018] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0019] In the flowcharts described in reference to the drawings, the order of the operations or steps can be changed, several operations or steps can be merged, a certain operation or step can be divided, and a specific operation or step can not be performed.

[0020] Figure 1 is a diagram illustrating a battery apparatus according to some embodiments.

[0021] Reference Figure 1 The battery apparatus 100 can be electrically connected to an external apparatus. In some embodiments, when the external apparatus is a load, the battery apparatus 100 can be discharged by operating as a power source that supplies power to the load. When the external apparatus is a charger, the battery apparatus 100 can be charged by receiving external power with the charger. In some embodiments, the external apparatus operating as a load can be, for example, an electronic device, a mobile device, or an energy storage system (ESS). The mobile device can be, for example, a vehicle such as an electric vehicle, a hybrid vehicle, or a smart mobile device.

[0022] The battery apparatus 100 can include a battery module 110 and a battery management system (BMS) 120.

[0023] The battery module 110 can include a plurality of battery cells (not shown). In some embodiments, the plurality of battery cells can be connected in series. In some embodiments, a predetermined number of battery modules 110 can be connected in series or in parallel to supply a desired power. The plurality of battery cells of the battery module 110 can be connected to the battery management system 120 respectively via a wire (a cell voltage sensing line). The battery management system 120 can collect and analyze information about the battery cells to control charging and discharging of the battery cells, cell balancing, protection operation, etc. The battery management system 120 can include a battery monitoring circuit 121 and a processor 122.

[0024] The battery monitoring circuit 121 can be connected to the plurality of battery cells included in the battery module 110 respectively via the cell voltage sensing line and monitor a state (e.g., a cell voltage) of the battery cells. In some embodiments, the battery monitoring circuit 121 can include a plurality of battery monitoring circuits 121 respectively corresponding to the plurality of battery modules 110. In some embodiments, one battery monitoring circuit 121 can correspond to two or more battery modules 110, or two or more battery monitoring circuits 121 can correspond to one battery module 110. In some embodiments, the battery monitoring circuit 121 can include a battery monitoring integrated circuit (BMIC) provided as an integrated circuit (IC).

[0025] The battery monitoring circuit 121 can include a plurality of cell balancing circuits (not shown) respectively corresponding to the plurality of battery cells. Each cell balancing circuit can perform cell balancing of the corresponding battery cell. The battery monitoring circuit 121 can measure (or sense) a cell voltage of each of the plurality of battery cells. The processor 122 can transmit a control signal to the battery monitoring circuit 121 to control the cell balancing of each battery cell based on the cell voltage of the corresponding battery cell.

[0026] The processor 122 can diagnose the cell voltage sensing line by controlling the cell balancing. When the processor 122 disables the cell balancing, the battery monitoring circuit 121 can measure the cell voltage of the battery cell via the cell voltage sensing line. Also, when the processor 122 enables the cell balancing, the battery monitoring circuit 121 can measure the cell voltage of the battery cell via the cell voltage sensing line. The processor 122 can diagnose the cell voltage sensing line connected to the corresponding battery cell based on the cell voltage measured when the cell balancing is disabled and the cell voltage measured when the cell balancing is enabled. If a difference between the cell voltage with the cell balancing disabled and the cell voltage with the cell balancing enabled is greater than a threshold ratio to the cell voltage (e.g., the cell voltage at the time when the cell balancing is disabled), the processor 122 can diagnose that the cell voltage sensing line is abnormal.

[0027] In some embodiments, the processor 122 can be processing circuitry, such as a microcontroller unit (MCU).

[0028] Figure 2 and Figure 3 is a diagram illustrating a method of diagnosing a cell voltage sense line according to some embodiments. In Figure 2 and Figure 3 , one battery cell is shown for convenience.

[0029] Referring to Figure 2 and Figure 3 , the cell voltage sense lines 211 and 212 can be connected to the positive and negative electrodes, respectively, for measuring the voltage of the battery cell CV N . The cell voltage sense line 211 can be a cell voltage sense line connected to the negative electrode of the battery cell CV N+1 adjacent to the battery cell CV N , and the cell voltage sense line 212 can be a cell voltage sense line connected to the positive electrode of the battery cell CV N-1 adjacent to the battery cell CV N .

[0030] The battery management system can include a resistor 221 connected between the cell voltage sense line 211 and the cell terminal CT N , and a resistor 222 connected between the cell voltage sense line 212 and the cell terminal CT N-1 . For example, one end of the cell voltage sense line 211 can be connected to the positive electrode of the battery cell CV N , the other end (node) N1 of the cell voltage sense line 211 can be connected to a first terminal of the resistor 221, and a second terminal of the resistor 221 can be connected to the cell terminal CT N . In addition, one end of the cell voltage sense line 212 can be connected to the negative electrode of the battery cell CV N , the other end (node) N2 of the cell voltage sense line 212 can be connected to a first terminal of the resistor 222, and a second terminal of the resistor 222 can be connected to the cell terminal CT N-1 .

[0031] The battery management system can include a balancing resistor 231 and a balancing switch 240. The balancing resistor 231 can be connected between the cell voltage sense line 211 and the cell balancing terminal CB N . For example, the balancing resistor 231 can be connected between the second end N1 of the cell voltage sense line 211 and the cell balancing terminal CB N . The balancing switch 240 can be connected between the cell balancing terminal CB N and the cell balancing terminal CB N-1 . The cell balancing terminal CBN-1 It can be connected to the cell voltage sensing line 212. For example, the cell balance terminal CB. N-1 It can be connected to the second terminal N2 of the cell voltage sensing line 212. In some embodiments, the balancing resistor 232 can be connected between the cell voltage sensing line 212 and the cell balancing terminal CB. N-1 Between. In this case, the balancing resistor 232 can be used for the battery cell CV. N-1 Cell balance.

[0032] In some embodiments, capacitor 260 may be connected to cell terminal CT. N and CT N-1 between.

[0033] In some implementations, the cell terminal CT N and CT N-1 and the cell balance terminal CB N and CB N-1 This could be a pin on the BMIC250. In this case, the BMIC 250 could include, for example... Figure 2 and Figure 3 The balance switch 240 shown.

[0034] In some implementations, the cell terminal CT N and CT N-1 It can be a pin on the BMIC 250, and the cell balance terminal CB N and CB N-1 It can be configured separately from the BMIC 250.

[0035] Refer again Figure 2 The battery management system can measure the CV of the battery cells when the balance switch 240 is off. N voltage V CVN Because no current flows in the cell voltage sensing lines 211 and 212 due to the off state of the balance switch 240, the measured voltage can be approximated to the CV of the battery cell. N The actual voltage.

[0036] refer to Figure 3 When the balance switch 240 is turned on, the battery management system can measure the CV of the battery cells. N voltage V CVN The balancing switch 240, when turned on, allows current to flow from the battery cell CV. N The path flows through cell voltage sensing line 211, resistor 231, switch 240, resistor 232, and cell voltage sensing line 212. Therefore, when the battery management system measures the CV of the battery cell... N voltage V CVNAs time passes, voltage drops can occur due to the line resistances 213 and 214 present in the cell voltage sense lines 211 and 212. If an anomaly is present in the cell voltage sense line 211 or 212, the resistance of the line resistance 213 or 214 can increase, and thus the measured battery cell CV N voltage can be low.

[0037] Accordingly, in some embodiments, the battery management system can diagnose whether an anomaly is present in the cell voltage sense line 211 or 212 based on the difference between the measured voltage V CVN (with balance off) when the balance switch 240 is off (i.e., cell balancing is disabled) and the measured voltage V CVN (with balance on) when the balance switch 240 is on (i.e., cell balancing is enabled).

[0038] On the other hand, when the voltage of the battery cell CV N is low, the current flowing through the balance resistances 231 and 232 is small, and thus the voltage drop across the line resistances 213 and 214 can be small. In this case, when diagnosing an anomaly in the cell voltage sense line 211 or 212 based only on the difference between the measured voltage V CVN (with balance off) when the balance switch 240 is off and the measured voltage V CVN (with balance on) when the balance switch 240 is on, the difference between the two voltages can be small, and the cell voltage sense line 211 or 212 can not be diagnosed correctly. Accordingly, in some embodiments, the battery management system can diagnose an anomaly in the cell voltage sense line 211 or 212 based on the difference between the measured voltage V CVN (with balance off) when the balance switch 240 is off and the measured voltage V CVN (with balance on) when the balance switch 240 is on, as well as the voltage of the battery cell CV N . In some embodiments, the measured voltage V CVN (with balance off) when the balance switch 240 is off can be used as the voltage CV N of the battery cell.

[0039] In some embodiments, the battery management system can diagnose that an anomaly is present in the cell voltage sense line 211 or 212 when the ratio between the difference between the measured voltage V CVN (with balance off) when the balance switch 240 is off and the measured voltage V CVN (with balance on) when the balance switch 240 is on, and the voltage of the battery cell CV N is greater than a threshold ratio V ratio . In some embodiments, the threshold ratio V ratiomay be set by experiment, for example, 0.02. In other words, if the ratio between the difference between the voltage V CVN (balance on) measured in a state in which the balancing switch 240 is turned off and the voltage V CVN (balance off) measured in a state in which the balancing switch 240 is turned on is greater than 0.02, it can be diagnosed that there is an abnormality in the cell voltage sensing line 211 or 212 (for example, an abnormality in the line resistance 213 or 214 of the cell voltage sensing line 211 or 212).

[0040] [Equation 1]

[0041]

[0042] As described above, the cell voltage sensing line can be diagnosed by the difference (|V CVN (balance off) - V CVN (balance on) |) of the measured voltages with respect to the voltage V N of the battery cell CV CVN , and thus even if the voltage of the battery cell CV N is low, an abnormality in the cell voltage sensing line can be accurately diagnosed.

[0043] In some embodiments, the battery management system can diagnose an abnormality in the cell voltage sensing line of each of a plurality of battery cells.

[0044] In some embodiments, the battery monitoring circuit (for example, 121 in Figure 1 ) of the battery management system can measure (that is, sense) the voltage of the battery cell CV N , and the processor (for example, 122 in Figure 1 ) of the battery management system can diagnose the cell voltage sensing line based on the measured voltage.

[0045] Figure 4 is a flowchart illustrating a method of diagnosing a cell voltage sensing line according to some embodiments.

[0046] Referring to Figure 4 , the battery management system can measure the voltage (first voltage) of the battery cell via the cell voltage sensing line when cell balancing is disabled (S410). The battery management system can measure the voltage (second voltage) of the battery cell via the cell voltage sensing line when cell balancing is enabled (S420).

[0047] The battery management system can calculate a ratio between a difference between a voltage of the battery cell measured when the battery cell balancing is disabled (first voltage) and a voltage of the battery cell measured when the battery cell balancing is enabled (second voltage) and the voltage of the battery cell measured when the battery cell balancing is disabled (first voltage) (S430). The battery management system can compare the calculated ratio to a threshold ratio (S440), and if the calculated ratio is greater than the threshold ratio, the battery management system can diagnose a cell voltage sense line abnormality (S450). In some embodiments, upon diagnosing the cell voltage sense line abnormality, the battery management system can generate an error flag indicating the cell voltage sense line abnormality (S460). In some embodiments, the battery management system can provide the error flag to an external device. Thus, the external device (or a user of the external device) can take action on the cell voltage sense line. In some embodiments, if the battery management system diagnoses the cell voltage sense line abnormality, the battery management system can shut down the battery management system to prevent the battery device from catching fire. If the calculated ratio is not greater than the threshold ratio, the battery management system can diagnose a cell voltage sense line no abnormality (S470).

[0048] While this application has been described in connection with what is presently considered to be the most practical embodiment, it is to be understood that the application is not to be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A battery management system configured to manage a battery cell, the battery management system comprising: a battery monitoring circuit connected to the battery cell via a cell voltage sense line and configured to measure a voltage of the battery cell as a first voltage via the cell voltage sense line when a cell balancing of the battery cell is disabled, and to measure a voltage of the battery cell as a second voltage via the cell voltage sense line when the cell balancing of the battery cell is enabled; and a processor configured to diagnose the cell voltage sense line based on a difference between the first voltage and the second voltage and the first voltage. the processor is further configured to diagnose that an abnormality exists in the cell voltage sense line when a ratio of the difference between the first voltage and the second voltage to the first voltage exceeds a threshold ratio.

2. The battery management system of claim 1, wherein, the processor is further configured to provide an error flag indicating the abnormality in the cell voltage sense line to an external device connected with a battery device including the battery management system.

3. The battery management system of claim 2, wherein, the cell voltage sense line includes a first cell voltage sense line connected between a positive electrode of the battery cell and a first node and a second cell voltage sense line connected between a negative electrode of the battery cell and a second node, 4. The battery management system of claim 1, wherein, wherein the battery management system further includes a first resistance connected between the first node and a first cell balancing terminal, and wherein the battery monitoring circuit includes a switch connected between the first cell balancing terminal and a second cell balancing terminal, the cell balancing is disabled by turning off the switch, and the cell balancing is enabled by turning on the switch.

5. The battery management system of claim 4, further comprising a second resistance connected between the second node and the second cell balancing terminal.

6. A battery device comprising: a battery cell; a first cell voltage sense line connected to a positive electrode of the battery cell; a second cell voltage sense line connected to a negative electrode of the battery cell; a first resistance connected between the first cell voltage sense line and a first cell balancing terminal; a switch connected between the first cell balancing terminal and a second cell balancing terminal, the second cell voltage sense line being connected to the second cell balancing terminal; and a processor configured to diagnose the first cell voltage sense line or the second cell voltage sense line based on a difference between a first voltage and a second voltage and the first voltage, the first voltage being a voltage between the first cell voltage sense line and the second cell voltage sense line measured when the switch is turned off, and the second voltage being a voltage between the first cell voltage sense line and the second cell voltage sense line measured when the switch is turned on. the processor is further configured to diagnose that an abnormality exists in the first cell voltage sense line or the second cell voltage sense line when a ratio of the difference between the first voltage and the second voltage to the first voltage exceeds a threshold ratio. ​ 7. The battery device according to claim 6, wherein ​ 8. The battery device according to claim 7, wherein The processor is further configured to provide an error flag indicating an abnormality in the cell voltage sense line to an external device connected to the battery apparatus.

9. The battery apparatus according to claim 7, further comprising a second resistor connected between the second cell voltage sense line and the second cell balance terminal.

10. A method of diagnosing a cell voltage sense line connected to a battery cell in a battery management system, the method comprising the steps of: measuring a voltage of the battery cell as a first voltage via the cell voltage sense line when a cell balancing of the battery cell is disabled; measuring a voltage of the battery cell as a second voltage via the cell voltage sense line when the cell balancing of the battery cell is enabled; and diagnosing the cell voltage sense line based on a difference between the first voltage and the second voltage and the first voltage.

11. The method of claim 10, wherein, The step of diagnosing the cell voltage sense line includes diagnosing the cell voltage sense line as abnormal when a ratio of the difference between the first voltage and the second voltage to the first voltage exceeds a threshold ratio.

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