A multi-pack parallel battery system and a relay normally open fault diagnosis method thereof

Abstract

The present invention discloses a multi-pack parallel battery system and a relay normally-open fault diagnosis method thereof, belonging to the field of battery status monitoring technology, including a BMS controller, at least two battery control modules and a high-voltage load circuit, wherein the battery control modules are electrically connected to the BMS controller; the battery control modules are connected to the high-voltage load after being connected in parallel; the battery control module includes a battery pack and three groups of relay conduction control circuits, a resistor R1 and an ammeter A1; the three groups of relay conduction control circuits are composed of a relay conduction control circuit 1, a relay conduction control circuit 2 and a relay conduction control circuit 3; the relay conduction control circuit 2 is connected in series with a resistor R1 and then connected in parallel with the relay conduction control circuit 1. Through the above-mentioned method, the technology of the present invention realizes the detection of the relay normally-open fault of multiple groups of parallel battery packs, thereby ensuring the working safety of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of battery status monitoring, and in particular to a multi-pack parallel battery system and a relay normally-open fault diagnosis method thereof. Background Art

[0002] At present, the main method used to diagnose the normally open fault of the battery pack relay is to compare the consistency of the voltage on the front and back sides of the relay. If the voltage on the front and back sides of the relay is consistent after the high-side drive and low-side drive switches of the relay are closed, the relay does not have a normally open fault. If the voltage difference between the front and back sides is too large, it is considered that the relay has a normally open fault.

[0003] Among many existing technologies, Chinese patent application CN117200145A discloses a battery-powered device, a vehicle and a relay fault detection method, which includes at least two battery packs and a control module; the battery pack includes a battery pack, a first main positive relay and a first main negative relay; at least two battery packs are connected in series to supply power to an external device; the first main positive relay and the first main negative relay are arranged in the battery pack, the first main positive relay is connected between the positive electrode of the battery pack and the positive electrode of the battery pack, and the first main negative relay is connected between the negative electrode of the battery pack and the negative electrode of the battery pack;

[0004] However, this patent application cannot judge the normally open fault of the relay, which makes it inconvenient to use.

[0005] Based on this, the present invention designs a multi-pack parallel battery system and a relay normally open fault diagnosis method thereof to solve the above problems. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a multi-pack parallel battery system and a relay normally-open fault diagnosis method thereof.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A multi-pack parallel battery system includes a BMS controller, at least two battery control modules and a high-voltage load circuit, wherein the battery control modules are electrically connected to the BMS controller;

[0009] The battery control modules are connected in parallel and electrically connected to a high-voltage load circuit;

[0010] The battery control module includes a battery pack, three sets of relay conduction control circuits, a resistor R1 and an ammeter A1;

[0011] The three groups of relay conduction control circuits are composed of relay conduction control circuit 1, relay conduction control circuit 2 and relay conduction control circuit 3;

[0012] The relay conduction control circuit 2 is connected in series with the resistor R1 and then connected in parallel with the relay conduction control circuit 1. The relay conduction control circuit 1 is electrically connected to the positive electrode of the battery pack, and the resistor R1 is electrically connected to the high-voltage load circuit.

[0013] One end of the relay conduction control circuit 3 is electrically connected to the negative electrode of the battery pack, and the other end of the relay conduction control circuit 3 is connected in series with the ammeter A1, and the ammeter A1 is electrically connected to the high-voltage load circuit and the BMS controller;

[0014] The main contact end of the relay conduction control circuit 2 is connected in series with the resistor R1 and then connected in parallel with the main contact end of the relay conduction control circuit 1. The two ends of the main contact end of the relay conduction control circuit 1 are electrically connected to the positive electrode of the battery pack and the high-voltage load circuit respectively;

[0015] One end of the main contact terminal of the relay conduction control circuit three is electrically connected to the negative electrode of the battery pack, and the other end of the main contact terminal of the relay conduction control circuit three is connected in series with the ammeter A1.

[0016] Furthermore, the double-contact relay circuit includes an auxiliary contact 1, an auxiliary contact 2, a main contact 1, a main contact 2, a moving reed, an electromagnetic coil, an input pin, a ground pin and a high-voltage moving contact;

[0017] The low-voltage moving contact piece and the high-voltage moving contact piece are fixedly installed at the upper and lower ends of the moving spring piece respectively;

[0018] The low-voltage moving contact is used to cooperate with the conduction between auxiliary contact 1 and auxiliary contact 2;

[0019] The high-voltage moving contact piece is used to cooperate with the conduction between the main contact 1 and the main contact 2;

[0020] The input pin and the ground pin are electrically connected to two ends of the electromagnetic coil respectively;

[0021] Auxiliary contact 1, input pin and ground pin are electrically connected to the conduction control circuit;

[0022] The electromagnetic coil and the moving spring are used in conjunction with electromagnetic action;

[0023] Auxiliary contact 2 is grounded.

[0024] Furthermore, the conduction control circuit includes a control pin 1, a current limiting resistor R3, a current limiting resistor R4, a current limiting resistor R5, a control pin 2, a controllable switch 1 and a controllable switch 2;

[0025] The base of the controllable switch 1 is electrically connected to one end of the current limiting resistor R3, the other end of the current limiting resistor R3 is electrically connected to the control pin 1, and the control pin 1 is electrically connected to the BMS controller;

[0026] The collector of the controllable switch 1 is electrically connected to the VCC power supply, and the emitter of the controllable switch 1 is electrically connected to the input pin;

[0027] The base of the controllable switch 2 is electrically connected to one end of the current limiting resistor R4, the other end of the current limiting resistor R4 is electrically connected to the control pin 2, and the control pin 2 is electrically connected to the BMS controller;

[0028] The collector of the controllable switch 2 is electrically connected to the ground pin, and the emitter of the controllable switch 2 is grounded;

[0029] One end of the current limiting resistor R5 is electrically connected to the auxiliary contact 1, and the other end of the current limiting resistor R5 is electrically connected to the VCC power supply;

[0030] Furthermore, the conduction control circuit also includes a measurement pin one, a measurement pin two and a measurement pin three.

[0031] Furthermore, the measurement pin 1 is electrically connected to the node P1 on the input pin, the measurement pin 2 is electrically connected to the node p2 on the ground pin, the measurement pin 3 is electrically connected to the node p3 on the auxiliary contact 1, and the measurement pin 1, the measurement pin 2, and the measurement pin 3 are all electrically connected to the BMS controller.

[0032] Furthermore, the high-voltage load circuit includes a high-voltage load, a high-voltage bus 1 and a high-voltage bus 2.

[0033] Furthermore, the positive and negative electrodes of the high-voltage load are electrically connected to the high-voltage bus 1 and the high-voltage bus 2 respectively, the high-voltage bus 1 is electrically connected to the resistor R, and the high-voltage bus 2 is electrically connected to the ammeter A1.

[0034] Furthermore, the high voltage load is an inverter module of a DC motor or an AC motor.

[0035] Furthermore, the BMS controller is also used to collect the voltage of the battery pack.

[0036] In order to better achieve the purpose of the present invention, the present invention also provides a relay normally open fault diagnosis method for a multi-pack parallel battery system, comprising the following steps:

[0037] Step 1: Send a high level to control pin 1 through the BMS controller. After the base of controllable switch 1 receives the high level, the emitter and collector of controllable switch 2 are turned on.

[0038] Step 2: The VCC voltage of the collector of the controllable switch 1 is transmitted to the two ends of the electromagnetic coil along the controllable switch 1;

[0039] Step 3: Check whether the voltages of the two nodes p1 and p2 at both ends of the electromagnetic coil are both VCC voltages by measuring pin 1 and pin 2;

[0040] If yes, go to step 4;

[0041] If not, the controllable switch 1 is not turned on, and the BMS controller reports a controllable switch 1 fault;

[0042] Step 4: Send a high level to the control pin 2 through the BMS controller. After the base of the controllable switch 2 receives the high level, the emitter and collector of the controllable switch 2 are connected.

[0043] Step 5: Measure the voltage at point p2 on pin 2 to see if it changes to 0;

[0044] If yes, go to step 6;

[0045] If not, the controllable switch 2 is not turned on, and the BMS controller reports a fault in the controllable switch 2;

[0046] Step 6: At this time, the electromagnetic coil is energized to generate magnetic force, and the moving spring moves upward under the action of the magnetic force, so that the high-voltage moving contact piece conducts the main contact 1 and the main contact 2, and the low-voltage moving contact piece conducts the auxiliary contact 1 and the auxiliary contact 2;

[0047] Step 7: Measure the voltage of point p3 at pin 3 to see if it changes from VCC to 0;

[0048] If yes, proceed to step eight;

[0049] If no, proceed to step nine;

[0050] Step 8: The BMS controller reports that the moving reed of the relay is normal;

[0051] Step nine, the BMS controller controls the high voltage load to run at 50kW for 5 seconds;

[0052] Step 10, the BMS controller reads the current values ​​of multiple groups of ammeters A1 and checks whether the total voltage of the battery pack changes;

[0053] If yes, the relay is judged to be closed normally, and the relay is reported to be in normal closed state;

[0054] If not, the BMS controller reports that the relay is normally open.

[0055] Compared with the prior art, the present invention has the following beneficial effects: 1. By detecting the voltage of the p1, p2 and p3 nodes, it is possible to judge whether the controllable switch 1, the controllable switch 2 and the moving reed are faulty in turn, thereby realizing accurate judgment of the relay fault;

[0056] 2. By performing relay open circuit fault detection on multiple groups of parallel battery control modules, it is achieved that when in use, each battery pack is connected to high-voltage bus 1 and high-voltage bus 2 and supplies power to the high-voltage load, thereby ensuring the total power of the high-voltage load is normal and ensuring the safe operation of the system.

[0057] 3. When the electromagnetic coil is energized and it is detected that the voltage at point p3 has not changed from VCC to 0, the high-voltage load is controlled by the BMS controller to run at 50kW for 5s, and the current value of ammeter A1 and the changes in the total voltage of the battery pack are observed to further confirm the status of the main contacts of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 A circuit diagram of a double-contact relay circuit of the present invention;

[0060] Figure 2 A circuit diagram of a conduction control circuit of the present invention;

[0061] Figure 3 The present invention is a circuit diagram of a multi-pack parallel battery system.

[0062] The numbers in the figure represent:

[0063] 100. Double-contact relay circuit; 101. Auxiliary contact one; 102. Auxiliary contact two; 103. Main contact one; 104. Main contact two; 105. Moving reed; 106. Electromagnetic coil; 107. Input pin; 108. Ground pin; 109. High-voltage moving contact; 110. Low-voltage moving contact; 200. Conducting control circuit; 201. Control pin one; 202. Measurement pin one; 203. Measurement pin two; 204. Control pin two; 205. Measurement pin three; 206. Controllable switch one; 207. Controllable switch two; 300. Battery pack; 400. High-voltage load circuit; 401. High-voltage load; 402. High-voltage bus one; 403. High-voltage bus two. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1-Figure 3 , a multi-pack parallel battery system, comprising a BMS controller, at least two battery control modules and a high voltage load circuit 400, wherein the battery control modules are electrically connected to the BMS controller;

[0066] The battery control modules are connected in parallel and electrically connected to the high voltage load circuit 400;

[0067] The battery control module includes a battery pack 300, three sets of relay conduction control circuits, a resistor R1 and an ammeter A1;

[0068] The three groups of relay conduction control circuits are composed of relay conduction control circuit 1, relay conduction control circuit 2 and relay conduction control circuit 3;

[0069] The relay conduction control circuit 2 is connected in series with the resistor R1 and then in parallel with the relay conduction control circuit 1. The relay conduction control circuit 1 is electrically connected to the positive electrode of the battery pack 300, and the resistor R1 is electrically connected to the high-voltage load circuit 400.

[0070] One end of the relay conduction control circuit 3 is electrically connected to the negative electrode of the battery pack 300, and the other end of the relay conduction control circuit 3 is connected in series with the ammeter A1, and the ammeter A1 is electrically connected to the high-voltage load circuit 400 and the BMS controller;

[0071] The relay conduction control circuit includes a double-contact relay circuit 100 and a conduction control circuit 200. The conduction control circuit 200 is electrically connected to the auxiliary contact terminal and the electromagnetic coil terminal of the double-contact relay circuit 100, and the conduction control circuit 200 is electrically connected to the BMS controller;

[0072] The main contact end of the relay conduction control circuit 2 is connected in series with the resistor R1 and then connected in parallel with the main contact end of the relay conduction control circuit 1. The two ends of the main contact end of the relay conduction control circuit 1 are electrically connected to the positive electrode of the battery pack 300 and the high-voltage load circuit 400 respectively.

[0073] One end of the main contact terminal of the relay conduction control circuit 3 is electrically connected to the negative electrode of the battery pack 300, and the other end of the main contact terminal of the relay conduction control circuit 3 is connected in series with the ammeter A1.

[0074] When the present invention is used, the high voltage power on and off of the battery pack 300 is realized through three sets of relay conduction control circuits. During the high voltage power on process, the BMS first outputs a high level to the base of the controllable switch 1 206 in the relay conduction control circuit 3, and then the emitter and collector of the controllable switch 1 206 are turned on, and then a high level is output to the base of the controllable switch 2 207 in the relay conduction control circuit, and then the emitter and collector of the controllable switch 2 207 are turned on, and finally the power supply voltage VCC will be applied to both ends of the relay drive coil, and a magnetic field will be generated after the coil is energized. Under the push of the magnetic field force, the moving contact piece moves upward and contacts with the moving contact point, and then the relay is closed, and the negative pole of the battery pack 300 is connected to the high voltage load circuit 400. Subsequently, the BMS controls the relay in the relay conduction control circuit 2 to close in the same manner, and the positive electrode of the battery pack 300 is connected to the high-voltage load circuit 400 after passing through the pre-charging resistor R1, and the battery pack 300 begins to pre-charge the high-voltage load circuit 400. When the voltage of the high-voltage load circuit 400 is pre-charged to be consistent with the voltage of the battery pack 300, the BMS controls the relay in the relay conduction control circuit 1 to close in the same manner, and then outputs a low level to the base of the controllable switch 1 206 and the controllable switch 2 207 in the relay conduction control circuit 2, and controls the relay in the conduction control circuit 2 to be disconnected, thereby realizing that the positive electrode of the battery pack 300 is connected to the positive electrode of the load through the relay conduction control circuit 1, and the negative electrode of the battery pack 300 is connected to the negative electrode of the load through the relay conduction control circuit 3, and the high voltage power-on is completed.

[0075] During the high-voltage power-off process, the BMS outputs a low level to the base of the controllable switch 1 206 and the controllable switch 2 207 in the relay conduction control circuit 1 and the relay conduction control circuit 3, and controls the relays in the relay conduction control circuit 1 and the relay conduction control circuit 3 to be disconnected, thereby disconnecting the connection between the battery pack 300 and the high-voltage load circuit 400, and completing the high-voltage power-off.

[0076] Embodiment 2: In some embodiments, Figure 1-Figure 3 As shown, as a preferred embodiment of the present invention, the double-contact relay circuit 100 includes an auxiliary contact 1 101, an auxiliary contact 2 102, a main contact 1 103, a main contact 2 104, a moving reed 105, an electromagnetic coil 106, an input pin 107, a ground pin 108 and a high-voltage moving contact 109;

[0077] The low-voltage moving contact piece 110 and the high-voltage moving contact piece 109 are fixedly mounted on the upper and lower ends of the moving spring piece 105 respectively;

[0078] The low-voltage moving contact piece 110 is used to cooperate with the conduction between the auxiliary contact 1 101 and the auxiliary contact 2 102;

[0079] The high-voltage moving contact piece 109 is used to cooperate with the conduction between the main contact 1 103 and the main contact 2 104;

[0080] The input pin 107 and the ground pin 108 are electrically connected to the two ends of the electromagnetic coil 106 respectively;

[0081] The auxiliary contact 101, the input pin 107 and the ground pin 108 are electrically connected to the conduction control circuit 200;

[0082] The electromagnetic coil 106 and the movable spring 105 cooperate with each other to work together with electromagnetic action;

[0083] Auxiliary contact 2 102 is grounded;

[0084] The conduction control circuit 200 includes a control pin 1 201, a current limiting resistor R3, a current limiting resistor R4, a current limiting resistor R5, a control pin 2 204, a controllable switch 1 206 and a controllable switch 2 207;

[0085] The base of the controllable switch 1 206 is electrically connected to one end of the current limiting resistor R3, the other end of the current limiting resistor R3 is electrically connected to the control pin 1 201, and the control pin 1 201 is electrically connected to the BMS controller;

[0086] The collector of the controllable switch 206 is electrically connected to the VCC power supply, and the emitter of the controllable switch 206 is electrically connected to the input pin 107;

[0087] The base of the second controllable switch 207 is electrically connected to one end of the current limiting resistor R4, the other end of the current limiting resistor R4 is electrically connected to the second control pin 204, and the second control pin 204 is electrically connected to the BMS controller;

[0088] The collector of the second controllable switch 207 is electrically connected to the ground pin 108, and the emitter of the second controllable switch 207 is grounded;

[0089] One end of the current limiting resistor R5 is electrically connected to the auxiliary contact 101, and the other end of the current limiting resistor R5 is electrically connected to the VCC power supply;

[0090] The conduction control circuit 200 further includes a measurement pin 1 202 , a measurement pin 203 , and a measurement pin 3 205 ;

[0091] The measuring pin 1 202 is electrically connected to the node P1 on the input pin 107, the measuring pin 2 203 is electrically connected to the node p2 on the ground pin 108, the measuring pin 3 205 is electrically connected to the node p3 on the auxiliary contact 1 101, and the measuring pin 1 202, the measuring pin 203, and the measuring pin 3 205 are all electrically connected to the BMS controller;

[0092] The high voltage load circuit 400 includes a high voltage load 401, a high voltage bus 1 402 and a high voltage bus 2 403;

[0093] The positive and negative electrodes of the high-voltage load 401 are electrically connected to the high-voltage bus 1 402 and the high-voltage bus 2 403 respectively. The high-voltage bus 1 402 is electrically connected to the resistor R1, and the high-voltage bus 2 403 is electrically connected to the ammeter A1.

[0094] When the present invention is used, by detecting the voltage of the p1, p2 and p3 nodes, it can judge in turn whether the controllable switch 1 206, the controllable switch 2 207 and the moving reed 105 are faulty, thereby realizing accurate judgment of the relay fault;

[0095] When the present invention is in use, by performing relay open circuit fault detection on multiple groups of parallel battery control modules, each battery pack 300 is connected to the high-voltage bus 1 402 and the high-voltage bus 2 403 and supplies power to the high-voltage load 401, thereby ensuring the total power of the high-voltage load 401 is normal and ensuring the working safety of the system.

[0096] When the present invention is used, when the electromagnetic coil 106 is energized, it is detected that the voltage at point p3 has not changed from VCC to 0. At this time, the BMS controller controls the high-voltage load 401 to run at 50kW for 5s, and observes the current value of the ammeter A1 and the changes in the total voltage of the battery pack 300, so as to further confirm the state of the main contacts of the relay.

[0097] Embodiment 3: In some embodiments, Figure 1-Figure 3 As shown, as a preferred embodiment of the present invention, a method for diagnosing a relay normally open fault in a multi-pack parallel battery system is also provided, which also includes the following steps:

[0098] Step 1: Send a high level to the control pin 201 through the BMS controller. After the base of the controllable switch 206 receives the high level, the emitter and collector of the controllable switch 206 are connected.

[0099] Step 2: The VCC voltage of the collector of the controllable switch 1 206 is transmitted to the two ends of the electromagnetic coil 106 along the controllable switch 1 206;

[0100] Step 3: Check whether the voltages of the two nodes p1 and p2 at both ends of the electromagnetic coil 106 are both VCC voltages by measuring pin 1 202 and pin 2 203;

[0101] If yes, go to step 4;

[0102] If not, the controllable switch 1 206 is not turned on, and the BMS controller reports a fault in the controllable switch 1 206 ;

[0103] Step 4: Send a high level to the control pin 2 204 through the BMS controller. After the base of the controllable switch 2 207 receives the high level, the emitter and collector of the controllable switch 1 206 are connected.

[0104] Step 5: Check whether the voltage at point p2 is changed to 0 by measuring the voltage at pin 203;

[0105] If yes, go to step 6;

[0106] If not, the controllable switch 207 is not turned on, and the BMS controller reports that the controllable switch 207 is faulty;

[0107] Step 6: At this time, the electromagnetic coil 106 is energized to generate magnetic force, and the movable spring piece 105 moves upward under the action of the magnetic force, so that the high-voltage movable contact piece 109 conducts the main contact 1 103 and the main contact 2 104, and at the same time, the low-voltage movable contact piece 110 conducts the auxiliary contact 1 101 and the auxiliary contact 2 102;

[0108] Step 7, measure the voltage of point p3 at pin 3 205 to see whether it changes from VCC to 0;

[0109] If yes, proceed to step eight;

[0110] If no, proceed to step nine;

[0111] Step 8: The BMS controller reports that the movable reed 105 of the relay is normal;

[0112] Step nine, the BMS controller controls the high voltage load 401 to operate at 50 kW for 5 seconds;

[0113] Step 10, the BMS controller reads the current values ​​of the multiple sets of ammeters A1 and checks whether the total voltage of the battery pack 300 changes;

[0114] If yes, the relay is judged to be closed normally, and the relay is reported to be in normal closed state;

[0115] If not, the BMS controller reports that the relay is normally open.

[0116] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-pack parallel battery system, characterized in that: It includes a BMS controller, at least two battery control modules and a high-voltage load circuit, and the battery control modules are electrically connected to the BMS controller; The battery control modules are connected in parallel and electrically connected to a high-voltage load circuit; The battery control module includes a battery pack, three sets of relay conduction control circuits, a resistor R1 and an ammeter A1; The three groups of relay conduction control circuits are composed of relay conduction control circuit 1, relay conduction control circuit 2 and relay conduction control circuit 3; The relay conduction control circuit 2 is connected in series with the resistor R1 and then connected in parallel with the relay conduction control circuit 1. The relay conduction control circuit 1 is electrically connected to the positive electrode of the battery pack, and the resistor R1 is electrically connected to the high-voltage load circuit. One end of the relay conduction control circuit 3 is electrically connected to the negative electrode of the battery pack, and the other end of the relay conduction control circuit 3 is connected in series with the ammeter A1, and the ammeter A1 is electrically connected to the high-voltage load circuit and the BMS controller; The relay conduction control circuit includes a double-contact relay circuit and a conduction control circuit, the conduction control circuit is electrically connected to the auxiliary contact end and the electromagnetic coil end of the double-contact relay circuit, and the conduction control circuit is electrically connected to the BMS controller; The main contact end of the relay conduction control circuit 2 is connected in series with the resistor R1 and then connected in parallel with the main contact end of the relay conduction control circuit 1. The two ends of the main contact end of the relay conduction control circuit 1 are electrically connected to the positive electrode of the battery pack and the high-voltage load circuit respectively; One end of the main contact terminal of the relay conduction control circuit three is electrically connected to the negative electrode of the battery pack, and the other end of the main contact terminal of the relay conduction control circuit three is connected in series with the ammeter A1.

2. The multi-pack parallel battery system according to claim 1, characterized in that: The double-contact relay circuit (100) comprises an auxiliary contact 1 (101), an auxiliary contact 2 (102), a main contact 1 (103), a main contact 2 (104), a moving reed (105), an electromagnetic coil (106), an input pin (107), a ground pin (108) and a high-voltage moving contact (109); The low-voltage moving contact piece (110) and the high-voltage moving contact piece (109) are respectively fixedly mounted on the upper and lower ends of the moving spring piece (105); The low-voltage moving contact piece (110) is used to cooperate with the conduction between the auxiliary contact 1 (101) and the auxiliary contact 2 (102); The high-voltage moving contact piece (109) is used to cooperate with the conduction between the main contact 1 (103) and the main contact 2 (104); The input pin (107) and the ground pin (108) are electrically connected to two ends of the electromagnetic coil (106) respectively; Auxiliary contact 1 (101), input pin (107) and ground pin (108) are electrically connected to a conduction control circuit (200); The electromagnetic coil (106) and the movable spring (105) cooperate with each other to achieve electromagnetic effect; Auxiliary contact 2 (102) is grounded.

3. The multi-pack parallel battery system according to claim 2, characterized in that: The conduction control circuit (200) comprises a control pin 1 (201), a current limiting resistor R3, a current limiting resistor R4, a current limiting resistor R5, a control pin 2 (204), a controllable switch 1 (206) and a controllable switch 2 (207); The base of the controllable switch 1 (206) is electrically connected to one end of the current limiting resistor R3, the other end of the current limiting resistor R3 is electrically connected to the control pin 1 (201), and the control pin 1 (201) is electrically connected to the BMS controller; The collector of the controllable switch 1 (206) is electrically connected to the VCC power supply, and the emitter of the controllable switch 1 (206) is electrically connected to the input pin (107); The base of the controllable switch 2 (207) is electrically connected to one end of the current limiting resistor R4, the other end of the current limiting resistor R4 is electrically connected to the control pin 2 (204), and the control pin 2 (204) is electrically connected to the BMS controller; The collector of the second controllable switch (207) is electrically connected to the ground pin (108), and the emitter of the second controllable switch (207) is grounded; One end of the current limiting resistor R5 is electrically connected to the auxiliary contact 1 (101), and the other end of the current limiting resistor R5 is electrically connected to the VCC power supply.

4. The multi-pack parallel battery system according to claim 3, characterized in that: The conduction control circuit (200) further comprises a measurement pin one (202), a measurement pin two (203) and a measurement pin three (205).

5. The multi-pack parallel battery system according to claim 4, characterized in that: The measuring pin one (202) is electrically connected to the node P1 on the input pin (107), the measuring pin two (203) is electrically connected to the node p2 on the ground pin (108), the measuring pin three (205) is electrically connected to the node p3 on the auxiliary contact one (101), and the measuring pin one (202), the measuring pin two (203), and the measuring pin three (205) are all electrically connected to the BMS controller.

6. The multi-pack parallel battery system according to claim 5, characterized in that: The high-voltage load circuit (400) comprises a high-voltage load (401), a high-voltage busbar 1 (402) and a high-voltage busbar 2 (403).

7. The multi-pack parallel battery system according to claim 6, characterized in that: The positive and negative electrodes of the high-voltage load (401) are electrically connected to the high-voltage busbar 1 (402) and the high-voltage busbar 2 (403) respectively. The high-voltage busbar 1 (402) is electrically connected to the resistor R1, and the high-voltage busbar 2 (403) is electrically connected to the ammeter A1.

8. The multi-pack parallel battery system according to claim 7, characterized in that: The high-voltage load (401) is an inverter module of a DC motor or an AC motor.

9. The multi-pack parallel battery system according to claim 8, characterized in that: The BMS controller is also used to collect the voltage of the battery pack (300).

10. A method for diagnosing a relay normally open fault of a multi-pack parallel battery system, using the multi-pack parallel battery system of claim 9, characterized in that: The following steps are involved: Step 1: Send a high level to control pin 1 through the BMS controller. After the base of controllable switch 1 receives the high level, the emitter and collector of controllable switch 2 are turned on. Step 2: The VCC voltage of the collector of the controllable switch 1 is transmitted to the two ends of the electromagnetic coil along the controllable switch 1; Step 3: Check whether the voltages of the two nodes p1 and p2 at both ends of the electromagnetic coil are both VCC voltages by measuring pin 1 and pin 2; If yes, go to step 4; If not, the controllable switch 1 is not turned on, and the BMS controller reports a controllable switch 1 fault; Step 4: Send a high level to the control pin 2 through the BMS controller. After the base of the controllable switch 2 (207) receives the high level, the emitter and collector of the controllable switch 2 are connected. Step 5: Measure the voltage at point p2 on pin 2 to see if it changes to 0; If yes, go to step 6; If not, the controllable switch 2 is not turned on, and the BMS controller reports a fault in the controllable switch 2; Step 6: At this time, the electromagnetic coil is energized to generate magnetic force, and the moving spring moves upward under the action of the magnetic force, so that the high-voltage moving contact piece conducts the main contact 1 and the main contact 2, and the low-voltage moving contact piece conducts the auxiliary contact 1 and the auxiliary contact 2; Step 7: Measure the voltage of point p3 at pin 3 to see if it changes from VCC to 0; If yes, proceed to step eight; If no, go to step nine; Step 8: The BMS controller reports that the moving reed of the relay is normal; Step nine, the BMS controller controls the high voltage load to run at 50kW for 5s; Step 10, the BMS controller reads the current values ​​of multiple groups of ammeters A1 and whether the total voltage of the battery pack changes; If yes, the relay is judged to be closed normally, and the relay is reported to be in normal closed state; If not, the BMS controller reports that the relay is normally open.

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