A battery pack leakage fault detection system and method for low-voltage energy storage system

Abstract

The invention discloses a battery pack leakage fault detection system and method for a low-voltage energy storage system, which belongs to the technical field of battery pack safety detection, and comprises a first relay, a second relay, a first triode and a second triode; the first relay is connected to the battery pack; the first relay is connected to the second relay through a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor in sequence; the first triode is connected to a control chip through a fourteenth resistor; the second triode is connected to the control chip through a thirteenth resistor; the first triode is connected to the first relay; the second triode is connected to the second relay; the first relay is connected to a first diode; the second relay is connected to a second diode; the second resistor is connected to the control chip through a first comparator and a second comparator in sequence; the fifth resistor is connected to the control chip through a third comparator and a fourth comparator in sequence.

Description

Technical Field

[0001] The invention belongs to the technical field of battery pack safety detection. The battery pack is used in bicycles, forklifts, low-speed vehicles and energy storage technology, and in particular relates to a battery pack leakage fault detection system and method for a low-voltage energy storage system. Background Art

[0002] As we all know, as the core energy storage component of electric bicycles, portable power supplies, and low-voltage energy storage systems, the safety and reliability of power batteries have always been the focus of attention. If the insulation between the battery pack and the metal parts such as the vehicle body and battery shell fails, and there are no other effective detection and protection measures, it is very easy to cause accidental short circuits and explosions and fires, which will cause serious harm to users and their property; currently, there is no leakage and leakage detection technology in low-voltage applications. Summary of the invention

[0003] In view of the above technical defects, the present invention provides a battery pack leakage and leakage fault detection system and method for a low-voltage energy storage system. When leakage and leakage occur, the specific location of the battery string that is leaking can be accurately found, and the dangerous situation can be eliminated accurately and quickly, thereby greatly improving the service life of the battery pack and ensuring the safety of the battery pack.

[0004] In order to achieve the above technical objectives, the present invention is implemented through the following technical solutions:

[0005] The first object of the present invention is to provide a battery leakage fault detection system for a low-voltage energy storage system, comprising a first relay, a second relay, a first triode and a second triode; wherein:

[0006] Pin No. 4 of the first relay is connected to the positive electrode of the battery pack; Pin No. 4 of the second relay is connected to the negative electrode of the battery pack and PGND respectively; Pin No. 3 of the first relay is connected to Pin No. 3 of the second relay through the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, and the sixth resistor in sequence; Pin No. 3 of the first relay is connected to GND through the first resistor, the second resistor, and the third resistor in sequence; GND is connected to the shell or the body of the battery system; The 12V positive terminal is connected to Pin No. 1 of the first relay and Pin No. 1 of the second relay respectively; The B pole of the first transistor is connected to the I / O terminal of the control chip through the fourteenth resistor; The B pole of the second transistor is connected to the I / O terminal of the control chip through the thirteenth resistor; The E poles of the first transistor and the E pole of the second transistor are both connected to GND; the C pole of the first transistor is connected to the second pin of the first relay; the C pole of the second transistor is connected to the second pin of the second relay; the first pin of the first relay is connected to the cathode of the first diode, and the second pin of the first relay is connected to the anode of the first diode; the first pin of the second relay is connected to the cathode of the second diode, and the second pin of the second relay is connected to the anode of the second diode; the third pin of the first relay is connected to the AD port of the control chip through the first resistor, the second resistor, the first comparator, and the second comparator in sequence; the third pin of the second relay is connected to the AD port of the control chip through the sixth resistor, the fifth resistor, the third comparator, and the fourth comparator in sequence.

[0007] Preferably, the resistance values ​​of the first resistor, the second resistor, the fifth resistor and the sixth resistor are equal, and the resistance values ​​of the third resistor and the fourth resistor are equal.

[0008] Preferably: the model of the control chip is N78E003AQ20.

[0009] Preferably: the comparison input terminal of the first comparator is connected to the output terminal of the first comparator through an eleventh resistor; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through a twelfth resistor; the comparison input terminal of the first comparator is connected to the output terminal of the first comparator through a tenth capacitor; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through a ninth capacitor.

[0010] Preferably, the first comparator and the third comparator are of model LM662.

[0011] The second object of the present invention is to provide a method for detecting a battery leakage fault for a low-voltage energy storage system. Based on the above-mentioned battery leakage fault detection system for a low-voltage energy storage system, the following steps are completed:

[0012] S1, when no test is performed, the first relay and the second relay are disconnected;

[0013] S2, when the detection circuit is started, the first relay and the second relay are closed;

[0014] GND refers to 1 / 2 of the power supply voltage. When no fault occurs, the first comparator and the second comparator form a first op amp, and the third comparator and the fourth comparator form a second op amp. The voltage values ​​output by the two op amps are equal to the absolute value of the difference of 1.65V, that is, Vo1=|1.65V-U1|=Vo2=|1.65V-U2|. When Vo2 is not equal to Vo1, it is determined that the system has a fault. Then S3 is executed.

[0015] S3, when Vo2-Vo1>0, the leakage or liquid leakage position is close to the negative electrode; when Vo2-Vo1<0, the leakage or liquid leakage position is close to the positive electrode;

[0016] S4. Determine the specific fault point by analyzing the values ​​of Vo1 and Vo2.

[0017] Preferably, S4 specifically includes: calculating the voltage between the first resistor and the third resistor and the voltage between the fourth resistor and the sixth resistor respectively through Vo1 and Vo2, and locating the specific fault point according to the battery cell voltage range of 2.5-4.2V.

[0018] The advantages and technical effects of the present invention are:

[0019] The present invention can accurately find the location of a battery string leaking liquid or electricity when leakage or electric leakage occurs, and can eliminate the danger accurately and quickly, thereby greatly improving the service life of the battery pack and ensuring the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 4 is a circuit diagram of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned purpose, control system and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The present invention is achieved in this way to solve the existing problems:

[0023] As the core energy storage component of electric bicycles, portable power supplies, and low-voltage energy storage systems, the safety and reliability of power batteries have always been the focus of attention. If the insulation between the battery pack and the metal parts such as the vehicle body and battery casing fails, and there are no other effective detection and protection measures, it is very easy to cause accidental short circuits and explosions and fires, which will cause serious harm to users and their property. At present, there is no leakage and leakage detection technology in low-voltage applications. The present invention can effectively and accurately solve such problems.

[0024] See also Figure 1 , a battery leakage fault detection system for a low-voltage energy storage system, mainly comprising: two relays, a first relay K1 and a second relay K2; a first transistor Q1 and a second transistor Q2 transistors are used to control the working states of the two relays respectively; the specific connection relationship is:

[0025] The No. 4 pin of the first relay K1 is connected to the positive electrode of the battery pack; the No. 4 pin of the second relay K2 is connected to the negative electrode of the battery pack and PGND respectively; the No. 3 pin of the first relay K1 is connected to the No. 3 pin of the second relay K2 through the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 in sequence; the No. 3 pin of the first relay K1 is connected to GND through the first resistor R1, the second resistor R2, and the third resistor R3 in sequence; GND is connected to the shell or the body of the battery system; the 12V positive terminal is connected to the No. 1 pin of the first relay K1 and the No. 1 pin of the second relay K2 respectively; the B pole of the first transistor Q1 is connected to the I / O terminal of the control chip through the fourteenth resistor R14; the B pole of the second transistor Q2 is connected to the I / O terminal of the control chip through the thirteenth resistor R13 O terminal is connected; the E pole of the first transistor Q1 and the E pole of the second transistor Q2 are both connected to GND; the C pole of the first transistor Q1 is connected to the No. 2 pin of the first relay; the C pole of the second transistor Q2 is connected to the No. 2 pin of the second relay; the No. 1 pin of the first relay K1 is connected to the cathode of the first diode, and the No. 2 pin of the first relay K1 is connected to the anode of the first diode; the No. 1 pin of the second relay K2 is connected to the cathode of the second diode, and the No. 2 pin of the second relay K2 is connected to the anode of the second diode; the No. 3 pin of the first relay K1 is connected to the AD port of the control chip through the first resistor R1, the second resistor R2, the first comparator, and the second comparator in sequence; the No. 3 pin of the second relay K2 is connected to the AD port of the control chip through the sixth resistor R6, the fifth resistor R5, the third comparator, and the fourth comparator in sequence.

[0026] Among them, the resistance values ​​of the first resistor, the second resistor, the fifth resistor and the sixth resistor are equal, and the resistance values ​​of the third resistor and the fourth resistor are equal.

[0027] The model of the control chip is N78E003AQ20.

[0028] The comparison input terminal of the first comparator is connected to the output terminal of the first comparator through the eleventh resistor Q11; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through the twelfth resistor R12; the comparison input terminal of the first comparator is connected to the output terminal of the first comparator through the tenth capacitor; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through the ninth capacitor.

[0029] The first comparator and the third comparator are of LM662 type.

[0030] The U3 circuit diagram is a voltage reference diagram.

[0031] Detection principle:

[0032] Among them, when no test is performed, the first relay K1 and the second relay K2 are disconnected to reduce the loss of the detection circuit; when the detection circuit is started, the first relay K1 and the second relay K2 are closed, and the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are connected in series and connected to the positive and negative poles of the battery system, and the midpoint of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 is connected to GND. In the figure, GND and PGND are isolated, and GND is connected to the outer casing or body of the battery system.

[0033] As mentioned above, GND refers to 1 / 2 of the power supply voltage. When there is no fault, the absolute value of the difference between the voltage output by the two op amps U1 and U2 and 1.65V is equal, that is, Vo1=|1.65V-U1|=Vo2=|1.65V-U2|; when Vo2≠Vo1, it can be determined that the system has a fault; further analysis: when Vo2-Vo1>0, the leakage or liquid leakage position is close to the negative electrode; when Vo2-Vo1<0, the leakage or liquid leakage position is close to the positive electrode;

[0034] After knowing whether the fault point is close to the positive pole or the negative pole, the specific fault point is determined by analyzing the values ​​of Vo1 and Vo2. The principle is as follows: because the voltage division ratios of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are known, the voltage between R1-R3 and the voltage between R4-R6 are calculated respectively by Vo1 and Vo2, and because the battery cell voltage ranges from 2.5-4.2V, the specific position of the specific fault point can be located.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery leakage fault detection system for a low-voltage energy storage system. Features: It includes a first relay, a second relay, a first triode and a second triode; wherein: Pin No. 4 of the first relay is connected to the positive electrode of the battery pack; Pin No. 4 of the second relay is connected to the negative electrode of the battery pack and PGND respectively; Pin No. 3 of the first relay is connected to Pin No. 3 of the second relay through the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, and the sixth resistor in sequence; Pin No. 3 of the first relay is connected to GND through the first resistor, the second resistor, and the third resistor in sequence; GND is connected to the shell or the body of the battery system; The 12V positive terminal is connected to Pin No. 1 of the first relay and Pin No. 1 of the second relay respectively; The B pole of the first transistor is connected to the I / O terminal of the control chip through the fourteenth resistor; The B pole of the second transistor is connected to the I / O terminal of the control chip through the thirteenth resistor; The E pole of the first transistor and the E pole of the second transistor are both connected to GND; the C pole of the first transistor is connected to the No. 2 pin of the first relay; the C pole of the second transistor is connected to the No. 2 pin of the second relay; the No. 1 pin of the first relay is connected to the cathode of the first diode, and the No. 2 pin of the first relay is connected to the anode of the first diode; the No. 1 pin of the second relay is connected to the cathode of the second diode, and the No. 2 pin of the second relay is connected to the anode of the second diode; the No. 3 pin of the first relay is connected to the AD port of the control chip through the first resistor, the second resistor, the first comparator, and the second comparator in sequence; the No. 3 pin of the second relay is connected to the AD port of the control chip through the sixth resistor, the fifth resistor, the third comparator, and the fourth comparator in sequence; The resistance values ​​of the first resistor, the second resistor, the fifth resistor and the sixth resistor are equal, and the resistance values ​​of the third resistor and the fourth resistor are equal; During fault detection, GND refers to 1 / 2 of the power supply voltage. When no fault occurs, the first comparator and the second comparator form a first op amp, and the third comparator and the fourth comparator form a second op amp. The voltage values ​​output by the two op amps are equal to the absolute value of the difference of 1.65V, that is, Vo1=|1.65V-U1|=Vo2=|1.65V-U2|. When Vo2 is not equal to Vo1, it is judged that the system has a fault. When Vo2-Vo1>0, the leakage or liquid leakage is close to the negative electrode; when Vo2-Vo1<0, the leakage or liquid leakage is close to the positive electrode; By analyzing the values ​​of Vo1 and Vo2, the specific fault point is determined: the voltage between the first resistor and the third resistor, and the voltage between the fourth resistor and the sixth resistor are calculated by Vo1 and Vo2 respectively, and the specific fault point is located according to the battery cell voltage range of 2.5-4.2V.

2. According to the low-voltage energy storage system battery leakage fault detection system of claim 1, Features: The model of the control chip is N78E003AQ20.

3. The battery pack leakage fault detection system for a low-voltage energy storage system according to claim 2, Features: The comparison input terminal of the first comparator is connected to the output terminal of the first comparator through the eleventh resistor; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through the twelfth resistor; the comparison input terminal of the first comparator is connected to the output terminal of the first comparator through the tenth capacitor; the comparison input terminal of the third comparator is connected to the output terminal of the third comparator through the ninth capacitor.

4. The battery pack leakage fault detection system for a low-voltage energy storage system according to claim 3, Features: The first comparator and the third comparator are of LM662 type.

5. A method for detecting leakage faults of a battery pack for a low-voltage energy storage system. Features: Based on the battery pack leakage fault detection system for a low-voltage energy storage system according to any one of claims 1 to 4, the following steps are completed: S1, when no test is performed, the first relay and the second relay are disconnected; S2, when the detection circuit is started, the first relay and the second relay are closed; GND refers to 1 / 2 of the power supply voltage. When no fault occurs, the first comparator and the second comparator form a first op amp, and the third comparator and the fourth comparator form a second op amp. The voltage values ​​output by the two op amps are equal to the absolute value of the difference of 1.65V, that is, Vo1=|1.65V-U1|=Vo2=|1.65V-U2|. When Vo2 is not equal to Vo1, it is determined that the system has a fault. Then S3 is executed. S3, when Vo2-Vo1>0, the leakage or liquid leakage position is close to the negative electrode; when Vo2-Vo1<0, the leakage or liquid leakage position is close to the positive electrode; S4. Determine the specific fault point by analyzing the values ​​of Vo1 and Vo2.

6. The method for detecting liquid leakage and electric leakage fault of a battery pack for a low-voltage energy storage system according to claim 5, Features: The S4 is specifically as follows: by using Vo1 and Vo2, the voltage between the first resistor and the third resistor and the voltage between the fourth resistor and the sixth resistor are calculated respectively, and according to the battery cell voltage range of 2.5-4.2V, the specific fault point is located.

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