Battery system capable of diagnosing battery pack relay and method thereof

Abstract

The present invention relates to a battery pack relay diagnosis system and method for preventing over and false detection of open circuit fault detection logic. When a vehicle is started, the system according to embodiments of the present invention sends a relay closing command from an ECU to a main battery management system (MBMS) and individual battery pack battery management systems (PBMSs). Upon receiving the command, the MBMS collects a junction box (J / B) current value, compares the collected current value with first and second threshold values, adjusts the current value, and sends the adjusted current value to each PBMS. Finally, each PBMS compares the adjusted J / B current value received from the MBMS and its own battery pack current value with third and fourth threshold values, and accurately diagnoses whether the battery pack relay has an open circuit fault based on the result.

Description

Technical Field

[0001] This invention relates to a battery pack protection device and method, and more specifically, to a battery system and method capable of performing battery pack relay diagnosis by applying bidirectional open-circuit fault detection logic. Background Technology

[0002] The battery system may include multiple battery packs connected in parallel in a junction box (J / B). Power can be supplied to the vehicle from the multiple battery packs through the junction box. As the number of battery packs connected in parallel increases, the battery system can provide greater power. Each of the multiple battery packs includes a battery pack relay connected to the junction box and a battery pack management system (PBMS) that controls the operation of the battery pack relay. Power can be supplied to the vehicle from each battery pack when the relay of each of the multiple battery packs is closed and the relay in the junction box is closed.

[0003] A Battery Management System (PBMS) is a system for monitoring and managing battery packs, and it controls the closing of battery pack relays after being activated. The PBMS then determines whether the battery pack relays are normally closed. The process of determining whether the battery pack relays are properly closed, or whether they failed to open when they should have, or whether they opened correctly, is referred to as battery pack relay diagnostics.

[0004] Specifically, for battery pack relay diagnostics, the PBMS measures the voltage at each terminal of the battery pack relay and compares the voltages at both ends. However, since one terminal of each of the multiple battery pack relays is connected to the junction box via a single-link busbar, the voltage at one terminal of an unclosed battery pack relay may become similar to the voltage of the battery pack. Therefore, in existing battery pack relay diagnostic methods, since multiple battery pack relays are diagnosed sequentially one after another, the battery pack relay diagnostic process takes a considerable amount of time.

[0005] To address this issue, research is currently underway on performing battery pack relay diagnostics by applying open-circuit fault detection logic.

[0006] Open-circuit fault detection logic is logic that detects electrical problems that occur when a circuit is open (disconnected), such as when a battery pack is not properly connected or the circuit is disconnected. This open-circuit fault detection logic is applicable to ISUZU vehicles, but there is a limitation: this open-circuit fault detection logic is only applicable to PBMSs that manage a maximum of 12 battery packs installed in ISUZU vehicles.

[0007] However, the number of battery packs installed in each vehicle may vary, and sometimes it is necessary to adjust the thresholds to monitor and manage the current (junction box current (J / B current)) of each battery pack in the PBMS. Furthermore, more monitoring time may be required to check if the current flowing through the battery packs is stable. That is, because the number of battery packs varies from vehicle to vehicle, the thresholds used to monitor the J / B current of each battery pack need to be adjusted, and sometimes a longer monitoring time is required to check if the J / B current is stable.

[0008] In order for the PBMS software to operate open-circuit fault detection logic to meet these requirements, changes must be made to adapt and monitor the software. However, the process and management of changing the PBMS software are complex and difficult, which presents a challenge.

[0009] As mentioned above, the open-circuit fault detection logic applied to ISUZU vehicles needs to be adjusted based on the number and status of each battery pack, but making and managing these changes in the software is a significant challenge.

[0010] Examples of related technologies include the following existing technical documents: (Patent Document 1) Korean Patent Application Publication No. 2023-0135715A (September 26, 2023) (Patent Document 2) Korean Patent Application Publication No. 2021-0058717A (May 24, 2021) Summary of the Invention

[0011] Technical issues

[0012] The present invention aims to provide a battery system and method capable of diagnosing battery pack relays by applying bidirectional open-circuit fault detection logic.

[0013] The present invention aims to provide a battery system and method that can perform battery pack relay diagnostics by applying open-circuit fault detection logic to the main battery management system (MBMS) to prevent over-detection and erroneous detection by the open-circuit fault detection logic.

[0014] Technical solution

[0015] According to an exemplary embodiment, a battery system for diagnosing battery pack relays is provided. The battery system includes an engine control unit (ECU) configured to send a closing command for each battery pack relay to a main battery management system (MBMS) constituting the vehicle battery system and respective battery pack battery management systems (PBMS) of two or more battery packs when the vehicle ignition switch is turned on. The MBMS is configured to, upon receiving the closing command from the ECU, collect junction box current values ​​(J / B current values) from the junction box, compare the current values ​​of each battery pack and the J / B current values ​​with a first threshold and a second threshold, adjust the J / B current values ​​based on the comparison results, and send the adjusted values ​​to the PBMS mounted on each battery pack. The PBMS is configured to, upon receiving the closing command from the ECU, compare the J / B current values ​​received from the MBMS and the current values ​​of each battery pack with a third threshold and a fourth threshold, and diagnose an open-circuit fault in the battery pack relay based on the comparison results.

[0016] When at least one of the battery pack current values ​​sent from the battery pack installed in the vehicle is less than the first threshold, the MBMS can determine that the first condition is met, and when the J / B current value is greater than the second threshold, the MBMS can determine that the second condition is met.

[0017] The first threshold can be |0.2[A]|, and the second threshold can be |30[A]|.

[0018] When the first condition is maintained for a predetermined first reference time or longer, the MBMS can determine that the first condition is met.

[0019] When both the first and second conditions are met, the MBMS can directly send the J / B current value to the PBMS. When either the first or second condition is not met, the MBMS can adjust the J / B current value to 0 [A] and then send the adjusted J / B current value to the PBMS.

[0020] The MBMS may include a current comparison unit and a current setting unit. The current comparison unit is configured to compare the J / B current value with a first threshold and a second threshold, and the current setting unit is configured to set the J / B current value sent to the PBMS installed on each battery pack to an adjusted J / B current value based on the comparison result of the current comparison unit.

[0021] The PBMS can send the current value of each battery pack collected from each battery pack connected to the PBMS to the MBMS.

[0022] The third threshold can be |5[A]|, and the fourth threshold can be |0.2[A]|.

[0023] When the J / B current value is greater than the third threshold, the PBMS can determine that the third condition is met, and when the battery pack current value of each battery pack is less than the fourth threshold, the PBMS can determine that the fourth condition is met.

[0024] The PBMS can determine that the third condition is met if the third condition is maintained for a predetermined second reference time or longer.

[0025] When both the third and fourth conditions are met, a battery pack relay open circuit fault can be diagnosed.

[0026] The PBMS may include a diagnostic unit configured to compare the J / B current value with current values ​​collected from each battery pack connected to the PBMS, and to diagnose a battery pack relay open-circuit fault based on the comparison results.

[0027] The battery system capable of diagnosing the battery pack relays also includes a battery pack relay located between each battery pack and the junction box, the battery pack relay receiving control signals from the PBMS and disconnecting and connecting the electrical connection between the battery pack and the junction box; a battery pack connected to each battery pack relay and providing energy according to the operation of the battery pack relay; and a junction box connected to the battery pack relay of each battery pack and connecting and protecting the circuitry of each battery pack, and connected to the PBMS and providing current from the battery packs to external loads.

[0028] According to an exemplary embodiment, a method for diagnosing a battery pack relay includes: (a) turning on a vehicle start switch; (B) receiving a closing command for the battery pack relay from an ECU via an MBMS and two or more PBMSs; (C) sending current values ​​of each battery pack collected from the battery packs connected to the PBMS to the MBMS at each PBMS; (D) collecting J / B current values ​​from the junction box connected to the MBMS at the MBMS; and (E) comparing the current values ​​of each battery pack sent from the PBMS and the J / B current values ​​at the MBMS with a first threshold and a second threshold, and sending an adjusted J / B current value to the PBMS installed on each battery pack based on the comparison result, and diagnosing an open-circuit fault in the battery pack relay based on the comparison result.

[0029] Step (E) may include: a first comparison step comparing the battery pack current value of each battery pack with a first threshold; a step determining that the first condition is met when the result of the first comparison is that at least one battery pack current value is less than the first threshold; a second comparison step comparing the J / B current value with a second threshold when the result of the first comparison is met; a step determining that the second condition is met when the result of the second comparison is that the J / B current value is greater than the second threshold; a step sending the J / B current value to the PBMS installed on each battery pack when both the first and second conditions are met; and a step adjusting the J / B current value to 0[A] and then sending the adjusted J / B current value to the PBMS installed on each battery pack when neither the first nor the second condition is met.

[0030] Step (F) may include: a third comparison step of comparing the J / B current value with a third threshold; a step of determining that a third condition is met when the result of the third comparison is that the J / B current value is greater than the third threshold; a fourth comparison step of comparing the received current value of each battery pack with a fourth threshold when the result of the third comparison is that the result of the third comparison is that the current value of the battery pack is less than the fourth threshold; and a step of diagnosing an open-circuit fault in the battery pack relay when both the third condition and the fourth condition are met.

[0031] Beneficial effects

[0032] According to an embodiment of the present invention, by applying open-circuit fault detection logic to the main battery management system (MBMS) instead of the relatively difficult-to-change battery pack management system (PBMS), over-detection and false detection of the open-circuit fault detection logic can be prevented. Attached Figure Description

[0033] Figure 1 This is a diagram illustrating the structure of a battery system capable of performing battery pack relay diagnostics according to an embodiment of the present invention; and

[0034] Figure 2 This is a flowchart illustrating a diagnostic method for a battery pack relay according to an embodiment of the present invention. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the exemplary embodiments disclosed below, but will be implemented in various different forms. Exemplary embodiments of the present invention are provided only to make the invention complete and to enable those skilled in the art to fully understand the scope of this disclosure. Here, the drawings may be enlarged to describe the disclosure in detail, and the same reference numerals denote the same elements in the drawings.

[0036] Figure 1 This is a diagram illustrating the structure of a battery system capable of performing battery pack relay diagnostics according to an embodiment of the present invention.

[0037] Reference Figure 1 According to an embodiment of the present invention, a battery system capable of performing battery pack relay diagnostics includes an engine control unit (ECU) 100, a main battery management system (MBMS) 200, a battery pack management system (PBMS) 300, a battery pack relay 400, a battery pack 500, and a junction box 600. In this configuration, the vehicle is equipped with one MBMS and up to 12 battery packs 500, with each battery pack 500 housing one PBMS 300.

[0038] ECU 100 is a component that controls the vehicle's engine and main system. When terminal 15 (KL 15) is turned on by turning on the vehicle's ignition switch, it sends commands to the MBMS that constitutes the vehicle's battery system and the individual PBMS of two or more battery packs to close the relays 400 of each battery pack.

[0039] When the ECU 100 receives a closing command from the battery pack relay 400 after terminal 15 (KL 15) is turned on, the MBMS 200 collects the junction box current value (J / B current value) from the junction box 600 and monitors the current flowing through each battery pack 500 in real time using the J / B current value. Furthermore, the collected current value of each battery pack 500 and the J / B current value of the junction box 600 are compared with a first threshold and a second threshold, and the J / B current value is adjusted according to the comparison result. The adjusted value is then sent to the PBMS 300 installed on each battery pack 500.

[0040] In this case, KL 15 is a circuit that is powered when the vehicle's ignition switch is turned on, and power is supplied to the KL 15 circuit when the vehicle's ignition switch is in the on position. That is to say, the turning on of KL 15 means that the vehicle's ignition switch is on and power is being supplied to the circuit, which occurs when the vehicle's engine is running or other electrical systems of the vehicle (such as radio, air conditioning, headlights, dashboard, etc.) are working.

[0041] Additionally, the first threshold can be |0.2[A]|, and the second threshold can be |30[A]|. However, the first and second thresholds can vary depending on the performance and function (purpose) of the battery system.

[0042] For example, when the ECU 100 receives a closing command from the battery pack relay 400 after KL 15 is turned on, the MBMS 200 compares at least one battery pack current value from the individual battery pack current values ​​sent from the battery packs 500 (up to 12) installed in the vehicle to determine whether the first condition of Equation 1 (first comparison) is met. In this case, if the first condition of Equation 1 is maintained for a predetermined first reference time (e.g., approximately 10 seconds or longer), it can be determined that the first condition is met, thereby allowing an additional stabilization time for the battery pack current to be applied to prevent misdiagnosis of the battery pack relay open-circuit fault detection logic.

[0043] [Formula 1]

[0044] That is, as shown in Equation 1, when at least one of the battery pack current values ​​of each battery pack 500 is less than |0.2[A]| which is the first threshold, MBMS 200 determines that the first condition of Equation 1 is satisfied.

[0045] In addition, when the result of the first comparison is that the first condition is met, the MBMS 200 compares the J / B current value collected from the junction box 600 again to determine whether the second condition of Equation 2 below is met (second comparison).

[0046] [Equation 2]

[0047] J / B current value > |30[A]|

[0048] That is, as described in Equation 2, if the J / B current value collected from the junction box 600 is greater than |30[A]| which is the second threshold, the MBMS 200 determines that the second condition of Equation 2 is satisfied.

[0049] Furthermore, if both the first and second conditions are met, the MBMS 200 will send the J / B current value collected from the junction box 600 to the PBMS 300 installed on each battery pack 500 unchanged. Alternatively, if neither the first nor the second condition is met, the MBMS 200 will adjust the J / B current value to 0 [A] and then send it to the PBMS 300 installed on each battery pack 500.

[0050] The PBMS 300 diagnoses relay open-circuit faults based on the received J / B current and the current of each battery pack. However, when the actual measured values ​​are unstable or are sent unchanged without conforming to standards, incorrect fault diagnosis may occur due to noise or measurement delay. To prevent this problem, the MBMS 200 determines whether a first and a second condition are met, and when the conditions are not met, masks the J / B current to "0" and sends it to the PBMS 300.

[0051] To this end, the MBMS 200 includes a current comparison unit 210 and a current setting unit 220. The current comparison unit 210 compares the J / B current value collected from the junction box 600 with a first threshold and a second threshold, and the current setting unit 220 sets the J / B current value sent to the PBMS 300 installed on each battery pack 500 to an adjusted J / B current value based on the comparison result of the current comparison unit 210.

[0052] The J / B current value refers to a specific current value of the battery system monitored and managed by the MBMS 200. In this invention, the J / B current value refers to the total current as the sum of all currents supplied from multiple battery packs connected in parallel, wherein the total current flows to the external load 700 through the junction box 600.

[0053] Meanwhile, only one MBMS 200 is installed on the vehicle, and the MBMS 200 is a component connected to the PBMS 300, ECU 100 and junction box 600 to integrate data received from multiple PBMS 300 by collecting the status of the battery pack 500 from the PBMS 300 and sending the collected status to the ECU 100, thereby enabling the management of the entire battery system.

[0054] If a closing command is received from the ECU 100 after terminal 15 (KL 15) is turned on, the PBMS 300 sends the current value collected from each battery pack 500 connected to the PBMS 300 to the MBMS 200. Additionally, the PBMS 300 compares the J / B current value received from the MBMS 200 and the current value of each battery pack 500 with a third and a fourth threshold, and diagnoses an open-circuit fault in the battery pack relay based on the comparison results. In this case, an open-circuit state of the battery pack relay means that the battery pack relay 400 is disconnected, and the open-circuit fault indicates a problem in the battery pack relay 400. It means that despite the closing command, the battery pack relay 400 remains disconnected or fails to establish a circuit connection due to internal mechanical / electrical defects, preventing current from flowing to the corresponding battery pack. Meanwhile, when an open circuit fault is diagnosed in the battery pack relay, a warning can be sent through the MBMS 200, or necessary protective measures can be taken to prevent overcurrent or undercurrent conditions in the battery system and ensure the stability and efficiency of the battery system.

[0055] In this case, the third threshold could be |5[A]|, and the fourth threshold could be |0.2[A]|. However, the third and fourth thresholds can vary depending on the performance and function (purpose) of the battery system.

[0056] For example, when PBMS 300 receives a closing command from ECU 100 for battery pack relay 400 after KL 15 is turned on, each PBMS 300 compares the J / B current value sent from MBMS 200 to determine whether the third condition (third comparison) of Equation 3 below is satisfied. In this case, PBMS 300 can determine that the third condition of Equation 3 is satisfied when the third condition is maintained for a predetermined second reference time (e.g., approximately 5 seconds or longer).

[0057] [Formula 3]

[0058] J / B current value > |5[A]|

[0059] That is, as described in Equation 3, when the J / B current value sent from MBMS 200 is greater than |5[A]| which is the third threshold, PBMS 300 determines that the third condition of Equation 3 is satisfied.

[0060] In addition, when the result of the third comparison is that the third condition is met, the PBMS 300 compares again the current value of each battery pack 500 collected from the battery pack 500 to determine whether the fourth condition of Equation 4 (fourth comparison) is met.

[0061] [Formula 4]

[0062] That is, as shown in Equation 4, when the battery pack current value of each battery pack 500 is less than |0.2[A]| which is the fourth threshold, the PBMS 300 determines that the fourth condition of Equation 4 is satisfied.

[0063] In addition, the PBMS 300 can diagnose battery pack relay open circuit faults when both the third and fourth conditions are met.

[0064] To this end, the PBMS 300 includes a diagnostic unit 310, which compares the J / B current value sent from the MBMS 200 with the current value collected from each battery pack 500 connected to the PBMS 300, and diagnoses a battery pack relay open circuit fault based on the comparison result.

[0065] Meanwhile, up to 12 PBMS 300s can be installed on the vehicle and connected to the battery pack relay 400 of the corresponding battery pack 500 as a component for managing individual battery packs 500 to monitor and control the status of the battery pack 500.

[0066] The battery pack relay 400 is a component used to disconnect and connect the electrical connection between the battery pack 500 and the junction box 600, and is located between each battery pack 500 and the junction box 600. It is operated by receiving control signals from the PBMS 300. That is, the battery pack relay 400 acts as a switch to connect or disconnect the battery pack 500 and the electrical system; when the battery pack relay 400 is closed, the battery pack and the electrical system are connected, allowing current to flow; and when the battery pack relay 400 is open, the connection is severed, preventing current flow.

[0067] Battery pack 500 is a component for storing and supplying energy, and is connected to each battery pack relay 400 to supply energy according to the operation of the battery pack relay 400.

[0068] Junction box 600 is a component used to connect and protect the circuitry of each battery pack 500, the battery pack relay 400 connected to each battery pack 500, and also connected to MBMS 200 to supply current from the battery pack 500 to the external load 700.

[0069] External load 700 is an external system (e.g., a motor, vehicle electrical system, etc.) that uses the current generated from battery pack 500 and is connected to junction box 600.

[0070] According to this configuration, by applying the logic related to the detection of open-circuit faults in the battery pack relay to only one MBMS 200 per vehicle, instead of the relatively difficult-to-change PBMS 300 which requires changing the threshold of the J / B current value and the additional monitoring time for stabilizing the battery pack current, it is possible not only to easily apply the threshold of the J / B current value, but also to apply the additional stabilization time of the battery pack current to prevent erroneous diagnosis of the open-circuit fault detection logic in the battery pack relay. Therefore, it also has the advantage of preventing over-detection and false detection of the open-circuit fault detection logic in the battery pack relay.

[0071] Hereinafter, a method for diagnosing a battery pack relay according to an embodiment of the present invention is described. The method for diagnosing a battery pack relay according to one embodiment of the present invention can be a method for processing signals received using a battery system capable of performing the above-described battery pack relay diagnosis, and therefore the above description regarding a battery system capable of performing battery pack relay diagnosis can be directly applied, and therefore redundant descriptions can be omitted.

[0072] Figure 2 This is a flowchart illustrating a diagnostic method for a battery pack relay according to one embodiment of the present invention.

[0073] Reference Figure 2 In the battery pack diagnostic method according to an embodiment of the present invention, firstly, when the vehicle ignition switch is turned on and terminal 15 (KL 15) is turned on (S10), MBMS 200 and two or more PBMS 300 receive a closing command from battery pack relay 400 from ECU 100 (S20).

[0074] Then, in PBMS 300, when a closing command is received from ECU 100 for battery pack relay 400 after terminal 15 (KL 15) is turned on, the current value of each battery pack 500 collected from the battery packs 500 respectively connected to PBMS 300 is sent to MBMS 200 (S30).

[0075] Additionally, in MBMS 200, after terminal 15 (KL 15) is closed, upon receiving a closing command from battery pack relay 400 from ECU 100, the J / B current value is collected from the junction box 600 connected to MBMS 200. The J / B current value is used to monitor in real time the current flowing out of each battery pack 500 received from multiple PBMS 300s (S40). In this case, the J / B current value refers to a specific current value of the battery system monitored and managed by MBMS 200. Here, the J / B current value represents the current measurement value of the battery pack, and J / B is an abbreviation for "junction box," which can refer to a device in a circuit that connects and protects multiple circuits.

[0076] Subsequently, at MBMS 200, the current value of each battery pack 500 and the J / B current value of the junction box 600 received from PBMS 300 are compared with the first threshold and the second threshold, and the J / B current value adjusted according to the comparison result is sent to PBMS 300 installed on each battery pack 500 (S50).

[0077] To describe the above S50 operation in more detail, firstly, the battery pack current value of each battery pack 500 is compared with a first threshold (|0.2[A]|) (first comparison) (S51). When the result of the first comparison is that at least one battery pack current value is less than the first threshold (|0.2[A]|) (S51), it is determined that the first condition is met.

[0078] In this case, when the first condition is met for a first reference time (e.g., about 10 seconds or longer), it can be determined that the first condition is met, so that an additional settling time for the battery pack current can be applied to prevent erroneous diagnosis of the battery pack relay open-circuit fault detection logic.

[0079] Furthermore, if the result of the first comparison indicates that the first condition is met (S51), the J / B current value is compared again with the second threshold (|30[A]|) (second comparison) (S52). When the result of the second comparison (S52) is that the J / B current value is greater than the second threshold (|30[A]|), the second condition is determined to be met.

[0080] If both the first and second conditions are met, the J / B current value collected from the junction box 600 is sent unchanged to the PBMS 300 installed on each battery pack 500 (S53). Alternatively, if either the first or second condition is not met, the J / B current value is adjusted to 0 [A], and then the adjusted J / B current value is sent to the PBMS 300 installed on each battery pack 500 (S54).

[0081] Subsequently, at each PBMS 300, the J / B current value received from MBMS 200 and the current value of each battery pack 500 are compared with the third and fourth thresholds, and a battery pack relay open-circuit fault is diagnosed based on the comparison results (S60). In this case, the battery pack relay open-circuit state refers to the state where the battery pack relay 400 is open. The battery pack relay open-circuit fault indicates that a problem has occurred in the battery pack relay 400, indicating that despite a closing command, the battery pack relay 400 still has the problem of remaining in the open state due to internal defects.

[0082] To describe the above S60 operation in more detail, firstly, the J / B current value sent from MBMS 200 is compared with a third threshold (|5[A]|) (third comparison) (S61). When the result of the third comparison (S61) is that the J / B current value is greater than the third threshold (|5[A]|), it is determined that the third condition is met.

[0083] In this case, when the third condition is met for a predetermined second reference time (e.g., about 5 seconds or longer), it can be determined that the third condition is met, so that an additional stabilization time for the battery pack current can be applied to prevent erroneous diagnosis of the battery pack relay open circuit fault detection logic.

[0084] Furthermore, if the result of the third comparison indicates that the third condition is met (S61), the current values ​​of each battery pack 500 collected from the battery pack 500 are compared again with the fourth threshold (|0.2[A]|) (fourth comparison) (S62). If the result of the fourth comparison (S62) indicates that the current value of the battery pack 500 is less than the fourth threshold (|0.2[A]|), the fourth condition is met.

[0085] If both the third and fourth conditions are met, a battery pack relay open circuit fault is diagnosed (S63). Alternatively, if neither the third nor the fourth condition is met, it is determined that there is no battery pack relay open circuit fault.

[0086] Meanwhile, when an open circuit fault is diagnosed in the battery pack relay, a warning can be sent through the MBMS 200, or necessary protective measures can be taken to prevent overcurrent or undercurrent conditions in the battery system and ensure the stability and efficiency of the battery system.

[0087] While specific terminology has been used to describe and illustrate preferred embodiments of the invention above, these terms are for the purpose of clearly describing the invention only, and it will be apparent that various modifications and changes can be made to the embodiments of the invention and the terminology described therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. These variations should not be construed solely as falling within the spirit and scope of the invention, but should be interpreted as falling within the scope of the claims of the invention.

[0088] The names of the components used in the specification and drawings of this invention are as follows.

[0089] 100: ECU 200: MBMS

[0090] 210: Current comparison unit; 220: Current setting unit

[0091] 300: PBMS 310: Diagnostic Unit

[0092] 400: Battery pack relay; 500: Battery pack

[0093] 600: Junction box; 700: External load

Claims

1. A battery system for diagnosing a battery pack relay, the battery system comprising: An engine control unit (ECU) is configured to send a closing command for each battery pack relay to the main battery management system (MBMS) that constitutes the vehicle battery system and the respective battery pack battery management systems (PBMS) of two or more battery packs when the vehicle ignition switch is turned on. The MBMS is configured to, when receiving the closing command from the battery pack relay from the ECU, collect the junction box current value (J / B current value) from the junction box, compare the current value of each battery pack and the J / B current value with a first threshold and a second threshold, adjust the J / B current value according to the comparison result, and send the adjusted J / B current value to the PBMS installed on each battery pack. as well as The PBMS is configured to, when receiving the closing command of the battery pack relay from the ECU, compare the J / B current value and the current value of each battery pack received from the MBMS with a third threshold and a fourth threshold, and diagnose an open circuit fault of the battery pack relay based on the comparison result.

2. The battery system of claim 1, wherein, The MBMS determines that a first condition is met when at least one of the battery pack current values ​​sent from the battery pack installed in the vehicle is less than the first threshold, and the MBMS determines that a second condition is met when the J / B current value is greater than the second threshold.

3. The battery system of claim 2, wherein, The first threshold is |0.2[A]|, and the second threshold is |30[A]|.

4. The battery system of claim 3, wherein, When the first condition is maintained for a predetermined first reference time or longer, the MBMS determines that the first condition is met.

5. The battery system of claim 3, wherein, When both the first and second conditions are met, the MBMS sends the J / B current value collected from the junction box to the PBMS unchanged, and when either the first or the second condition is not met, the J / B current value is adjusted to 0 [A] and then the adjusted J / B current value is sent to the PBMS.

6. The battery system according to claim 1, wherein, The MBMS includes: A current comparison unit, configured to compare the J / B current value with a first threshold and a second threshold; and A current setting unit is configured to set the J / B current value sent to the PBMS installed on each battery pack to an adjusted J / B current value based on the comparison result of the current comparison unit.

7. The battery system according to claim 1, wherein, The PBMS sends the current value of each battery pack collected from each battery pack connected to the PBMS to the MBMS.

8. The battery system according to claim 1, wherein, The third threshold is |5[A]|, and the fourth threshold is |0.2[A]|.

9. The battery system according to claim 8, wherein, When the J / B current value is greater than the third threshold, the PBMS determines that the third condition is met, and when the current value of each battery pack is less than the fourth threshold, the PBMS determines that the fourth condition is met.

10. The battery system according to claim 9, wherein, The PBMS determines that the third condition is met when the third condition is maintained for a predetermined second reference time or longer.

11. The battery system according to claim 9, wherein, When both the third and fourth conditions are met, a battery pack relay open circuit fault is diagnosed.

12. The battery system according to claim 1, wherein, The PBMS includes a diagnostic unit configured to compare the J / B current value with the current value of each battery pack collected from the battery packs respectively connected to the PBMS, and to diagnose a battery pack relay open circuit fault based on the comparison result.

13. The battery system according to claim 1, further comprising: A battery pack relay, located between each battery pack and the junction box, and configured to receive control signals from the PBMS to disconnect and close the electrical connection between the battery pack and the junction box; A battery pack, which is connected to each battery pack relay and is configured to supply energy according to the operation of the battery pack relay; as well as A junction box is connected to the battery pack relay of each battery pack to connect and protect the circuitry of each battery pack, and is also connected to the MBMS to supply current from the battery pack to an external load.

14. A method for diagnosing a battery pack relay, the method comprising the following steps: (A) The steps for turning on the vehicle's ignition switch; (B) The steps of receiving closing commands from the ECU via MBMS and two or more PBMS; (C) The step of sending the current value of each battery pack collected from the battery pack connected to the PBMS to the MBMS at each PBMS; (D) The step of collecting the J / B current value from the junction box connected to the MBMS at the MBMS; (E) At the MBMS, the current value of each battery pack and the J / B current value sent from the PBMS are compared with a first threshold and a second threshold, and the adjusted J / B current value according to the comparison result is sent to the PBMS installed on each battery pack. as well as (F) At each PBMS, the J / B current value sent from the MBMS and the current value of each battery pack are compared with the third threshold and the fourth threshold, and the battery pack relay open circuit fault is diagnosed based on the comparison results.

15. The method according to claim 14, wherein, Step (E) includes: The first comparison step is to compare the battery pack current value of each battery pack with a first threshold. When the result of the first comparison is that at least one of the battery pack current values ​​is less than the first threshold, the step of determining that the first condition is met is performed. When the result of the first comparison meets the first condition, a second comparison step is performed to compare the J / B current value with a second threshold. When the result of the second comparison is that the J / B current value is greater than the second threshold, the step of determining that the second condition is met is performed. The step of sending the J / B current value to the PBMS installed on each battery pack when the first and second conditions are met; and When the first condition or the second condition is not met, the J / B current value is adjusted to 0 [A], and then the adjusted J / B current value is sent to the PBMS installed on each battery pack.

16. The method according to claim 15, wherein, The first threshold is |0.2[A]|, and the second threshold is |30[A]|.

17. The method according to claim 15, wherein, In the step of determining whether the first condition is met, the first condition is determined to be met when the first condition is met for a predetermined first reference time or longer.

18. The method according to claim 14, wherein, The step (F) includes: The third comparison step involves comparing the J / B current value with a third threshold. When the result of the third comparison is that the J / B current value is greater than the third threshold, the step of determining that the third condition is met is performed. When the result of the third comparison is satisfied, a fourth comparison step is taken to compare the received current value of each battery pack with a fourth threshold. When the result of the fourth comparison is that the battery pack current value is less than the fourth threshold, the step of determining that the fourth condition is met; and The steps for diagnosing an open-circuit fault in the battery pack relay are as follows: when both the third and fourth conditions are met.

19. The method according to claim 18, wherein, The third threshold is |5[A]|, and the fourth threshold is |0.2[A]|.

20. The method according to claim 18, wherein, In the step of determining whether the third condition is met, the third condition is determined to be met when the third condition is met for a predetermined second reference time or longer.

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