Battery system electric leakage detection system and method

Abstract

The invention provides a battery system electric leakage detection system and method. The battery system electric leakage detection system comprises a normal circuit module, a main loop electric leakage induction loop, a PWM pulse emission module and an electric leakage detection module. The normal circuit module is connected with the battery system, the main loop electric leakage induction loop and the PWM pulse transmitting module; the normal circuit module is provided with a normal voltage node, the main loop electric leakage induction loop comprises a conductive material wrapping the insulating outer layer of the main loop, the main loop electric leakage induction loop is provided with an induction voltage node used for detecting whether electric leakage or short circuit occurs in the main loop, and the electric leakage detection module is provided with a detection node. According to the invention, the normal voltage node is arranged in the normal circuit module, the induced voltage node is arranged in the main circuit electric leakage induction loop, and the detection node is arranged in the electric leakage detection module, so that various states of electric leakage of the battery system can be detected through the waveform of the voltage of each node without adopting complex control logic; the battery system electric leakage detection cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of battery system leakage detection, and in particular to a battery system leakage detection system and method. Background Art

[0002] In recent years, new energy four-wheel and two-wheel vehicles have developed rapidly, and lithium batteries of different voltage platforms have become popular. In order to solve the problem of fast charging, the voltage platform has gradually increased from 380V to 800V, but the higher the voltage, the higher the risk factor, especially in the event of abnormal conditions such as leakage and short circuit, the harm is extremely great; circuit leakage or short circuit will cause direct harm to the human body, and it is easy to cause fire. At present, the use scenarios of electric vehicles are diverse and long-term. The circuit is prone to leakage, short circuit or open circuit caused by friction, vibration and aging. At present, the industry's technical detection of short circuit or open circuit is relatively mature, but leakage detection technology is relatively rare, mainly affected by high cost, and the probability of occurrence is relatively small. For this reason, manufacturers rarely quote relevant technologies for leakage. Therefore, the application of low-cost battery main circuit leakage detection is a key issue that needs to be solved in the industry.

[0003] Electric vehicle battery main circuit leakage is an important factor affecting safe driving. Electric vehicle battery main circuit leakage may be caused by a variety of reasons, such as line aging, poor connection, collision causing battery short circuit, etc. To prevent leakage, we currently need to take the following measures: First, choose electric vehicles with reliable quality, and try to avoid choosing low-quality or second-hand electric vehicles; second, regularly conduct a comprehensive inspection of the electric vehicle, especially the line connection parts, to ensure that the connection between the components is stable. The above is about the inability to self-detect and manage through the electric vehicle battery system:

[0004] Patent 202111354777.4 discloses a leakage detection method and a leakage detection device: after the pre-charging is completed and before the vehicle is in a drivable state, the controller receives a leakage detection command and the high-voltage module to be tested for leakage has no faults, and controls the high-voltage module to be tested for leakage to be energized to form a leakage detection circuit with the leakage detection module to perform leakage detection on the high-voltage module to be tested for leakage, wherein the duration of the energization of the high-voltage module to be tested for leakage is greater than the detection time of the leakage detection sensor in the leakage detection module; the leakage detection speed is slow, the control process is complex, the cost is high, and the applicability is low. Summary of the invention

[0005] In order to overcome the above technical defects, the present invention provides a battery system leakage detection system and method, which has a simple structure.

[0006] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0007] A battery system leakage detection system, the battery system is provided with a main circuit, including: a normal circuit module, a main circuit, a main circuit leakage induction circuit, a PWM pulse transmission module and a leakage detection module;

[0008] The normal circuit module is connected to the battery system, the main circuit, and the PWM pulse transmission module;

[0009] The normal circuit module is provided with a normal voltage node, the main circuit leakage induction circuit includes: a conductive material wrapped in the outer insulating layer of the main circuit, the main circuit leakage induction circuit is provided with an induction voltage node for detecting whether the main circuit is leaking or short-circuited, and the leakage detection module is provided with a detection node.

[0010] As a further improvement of the present invention, the normal circuit module comprises: a first resistor and a second resistor;

[0011] The positive electrode of the battery system is connected to the negative electrode of the battery system through the first resistor and the second resistor;

[0012] A connection point between the first resistor and the second resistor is grounded, and a connection point between the first resistor and the second resistor is the normal voltage node.

[0013] As a further improvement of the present invention, the leakage detection module includes: a third resistor, a fourth resistor, a fifth resistor, a first voltage regulator tube, a second voltage regulator tube and an analog / digital converter;

[0014] The main circuit is connected to the analog / digital converter through the third resistor and the fourth resistor;

[0015] The main circuit is grounded through the third resistor and the fifth resistor;

[0016] The third resistor is connected to the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube respectively, the negative electrode of the first voltage regulator tube is connected to the analog / digital converter, and the positive electrode of the second voltage regulator tube is grounded;

[0017] The connection point between the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube is a detection node.

[0018] As a further improvement of the present invention, the main circuit comprises: a sixth resistor, a seventh resistor, and an eighth resistor;

[0019] The PWM pulse transmitting module is connected to the positive electrode of the battery system through the seventh resistor and the sixth resistor;

[0020] The negative electrode of the battery system is connected to the third resistor through the eighth resistor;

[0021] The positive electrode of the battery system is connected to the negative electrode of the battery system through the sixth resistor and the eighth resistor;

[0022] A connection point between the sixth resistor and the eighth resistor is the induced voltage node.

[0023] As a further improvement of the present invention, the first resistor, the second resistor, the sixth resistor, and the eighth resistor have the same resistance value; the third resistor, the fourth resistor, the fifth resistor, and the seventh resistor have the same resistance value;

[0024] The normal circuit module is connected to the main loop leakage induction circuit through a switch.

[0025] Compared with the prior art, the battery system leakage detection system provided by the present invention has the following beneficial effects: by setting a normal circuit module, a main circuit, a main circuit leakage induction circuit, a PWM pulse transmission module and a leakage detection module, at the same time, a normal voltage node is set in the normal circuit module, an induction voltage node is set in the main circuit leakage induction circuit, and a detection node is set in the leakage detection module. Various states of battery system leakage can be detected through the waveforms of the voltages at each node. The structure is simple, and there is no need to adopt complex control logic, which can greatly reduce the detection cost of battery system leakage.

[0026] In addition, the present invention also provides a battery system leakage detection method, which is applied to the above leakage detection system. The battery system leakage detection method comprises the steps of:

[0027] When the voltage of the detection node pulses up and down on the neutral line, it is judged that there is no leakage, where the value of the neutral line is Among them, U 1 is the high level voltage of the PWM pulse transmitting module, U 0 is the voltage value of the normal voltage node;

[0028] When the voltage of the detection node is above the neutral line or below the neutral line, it is determined that the battery system is leaking;

[0029] When the voltage of the detection node is in a straight line, it is determined that the battery system is short-circuited or the sensing line is broken.

[0030] As a further improvement of the present invention, when the voltage of the detection node is located on the neutral line, it is determined that the positive electrode of the battery system is leaking.

[0031] As a further improvement of the present invention, when the voltage of the detection node is below the neutral line, it is determined that the negative electrode of the battery system is leaking.

[0032] As a further improvement of the present invention, when the voltage of the detection node is in a straight line and is located on the middle line, it is determined that the positive electrode of the battery system is short-circuited;

[0033] When the voltage of the detection node is in a straight line and is below the center line, it is determined that the negative electrode of the battery system is short-circuited.

[0034] As a further improvement of the present invention, when the voltage of the detection node is in a straight line and is located at the middle line, it is determined that the induction line of the battery system is broken.

[0035] Compared with the prior art, the battery system leakage detection method provided by the present invention has the following beneficial effects: on the basis of the battery system leakage detection system, the specific situation of the battery system leakage can be directly obtained through the voltage waveform of each node, without the need for complex control of the battery system, which can greatly improve the speed and difficulty of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The framework diagram of the battery system leakage detection system of the present invention;

[0037] Figure 2 A circuit diagram of the battery leakage detection system of the present invention;

[0038] Figure 3 is an equivalent circuit diagram of the battery leakage detection system of the present invention;

[0039] Figure 4 The equivalent circuit diagram of the battery leakage detection system of the present invention when the positive electrode is leaking;

[0040] Figure 5 The equivalent circuit diagram of the battery leakage detection system of the present invention when the positive electrode is short-circuited;

[0041] Figure 6 The equivalent circuit diagram of the battery leakage detection system of the present invention when the negative electrode is leaking;

[0042] Figure 7 The equivalent circuit diagram of the battery leakage detection system of the present invention when the negative electrode is short-circuited;

[0043] Figure 8 The equivalent circuit diagram of the battery leakage detection system of the present invention when the induction line is disconnected; Fig. 9 This is a waveform-fault comparison diagram of the battery leakage detection system of the present invention.

[0044] Explanation of the accompanying drawings: 1. Normal circuit module; 2. Main circuit; 3. PWM pulse transmission module; 4. Leakage detection module; 5. Main circuit leakage induction circuit.

[0045] 100. Battery system. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0047] Example 1

[0048] This embodiment discloses a battery system leakage detection system. The battery system 100 is provided with a main circuit 2, such as Figure 1 As shown, it includes: a normal circuit module 1, a PWM pulse transmitting module 3 and a leakage detection module 4; the normal circuit module 1 is connected to the battery system, the main circuit 2, and the PWM pulse transmitting module 3; the normal circuit module 1 is provided with a normal voltage node, and the main circuit leakage induction circuit 5 includes: a conductive material wrapped in the insulating outer layer of the main circuit 2, the main circuit leakage induction circuit 5 is provided with an induction voltage node for detecting whether the main circuit 2 is leaking or short-circuited, and the leakage detection module 4 is provided with a detection node.

[0049] like Figure 2 As shown, the normal circuit module 1 includes: a first resistor R1 and a second resistor R2; the positive electrode of the battery system is connected to the negative electrode of the battery system through the first resistor R1 and the second resistor R2; the connection point of the first resistor R1 and the second resistor R2 is grounded, and the connection point of the first resistor R1 and the second resistor R2 is a normal voltage node.

[0050] The leakage detection module 4 includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first voltage regulator D1, a second voltage regulator D2 and an analog / digital converter ADC; the main circuit 2 is connected to the analog / digital converter ADC through the third resistor R3 and the fourth resistor R4; the main circuit 2 is grounded through the third resistor R3 and the fifth resistor R5; the third resistor R3 is respectively connected to the positive electrode of the first voltage regulator D1 and the negative electrode of the second voltage regulator D2, the negative electrode of the first voltage regulator D1 is connected to the analog / digital converter ADC, and the positive electrode of the second voltage regulator D2 is grounded. The analog / digital converter ADC is used to convert an analog voltage signal into a digital voltage signal.

[0051] The main circuit 2 includes: a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8; the PWM pulse transmitting module 3 is connected to the positive electrode of the battery system through the seventh resistor R7 and the sixth resistor R6; the negative electrode of the battery system is connected to the third resistor R3 through the eighth resistor R8; the positive electrode of the battery system is connected to the negative electrode of the battery system through the sixth resistor R6 and the eighth resistor R8; the connection point between the sixth resistor R6 and the eighth resistor R8 is an induced voltage node.

[0052] The resistance values ​​of the first resistor R1 , the second resistor R2 , the sixth resistor R6 , and the eighth resistor R8 are equal.

[0053] The resistance values ​​of the third resistor R3 , the fourth resistor R4 , the fifth resistor R5 , and the seventh resistor R7 are equal.

[0054] The normal circuit module 1 is connected to the main loop leakage induction circuit through the switch K.

[0055] In this embodiment, a normal circuit module, a main circuit, a main circuit leakage induction circuit, a PWM pulse transmission module and a leakage detection module are arranged. At the same time, a normal voltage node is arranged in the normal circuit module, an induction voltage node is arranged in the main circuit leakage induction circuit, and a detection node is arranged in the leakage detection module. Various leakage states of the battery system can be detected through the waveforms of the voltages of each node. The structure is simple, and there is no need to adopt complex control logic, which can greatly reduce the detection cost of battery system leakage.

[0056] Example 2

[0057] This embodiment discloses a battery system leakage detection method, which is applied to the leakage detection system in Embodiment 1. The battery system leakage detection method comprises the following steps:

[0058] Before performing leakage detection, switch S1 needs to be in the closed state.

[0059] It should be noted that, since the resistance values ​​of the first resistor R1, the second resistor R2, the sixth resistor R6, and the eighth resistor R8 are equal, and the resistance values ​​of the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the seventh resistor R7 are equal, in order to facilitate description in the following text, the first resistor R1, the second resistor R2, the sixth resistor R6, and the eighth resistor R8 are equal. Figures 2 to 8 R1' is used instead; the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the seventh resistor R7 are replaced by R2', and the line in the main circuit leakage induction circuit 5 is equivalent to resistor R3'; the theoretical resistance of the leakage induction line is close to 0Ω, which is equivalent to R4'.

[0060] like Figure 3 As shown, without the influence of PWM pulse, the voltage U of the induced voltage node in the main circuit leakage induction circuit 5 is 2 With the normal voltage node voltage U 0 The same, the difference between the two is 0; when the PWM emitted by the PWM pulse transmitting module 3 is a high level voltage U 1 When the leakage detection module 4U 1 To U 3 The equivalent resistance between is: (R2'+R2') / / R2'=2 / 3R2', at this time, the detection node U 3 The voltage is: 3(U 1 -U 0 ) / 5; When PWM is a low level voltage, the leakage detection module 4U 3 To U 0The equivalent resistance between them is: (R2'+R2') / / R2'=2 / 3R2', at this time the detection node U 3 Voltage: 2(U 1 -U 0 ) / 5, according to the PWM high and low levels, the induced voltage node voltage U is formed 3 The low level is 2 (U 1 -U 0 ) / 5, high level is 3(U 1 -U 0 ) / 5, induced voltage node voltage U 3 It is consistent with the figure of the pulse width PWM pulse transmitting module 3, such as Fig. 9 The normal curve value in the working mode detection graph is (U 1 -U 0 ) / 2 midline up and down pulses; that is, when the induced voltage node voltage U 3 When the neutral line pulses up and down, it is judged that there is no leakage.

[0061] like Figure 4 As shown in the circuit diagram, at this time, the positive electrode of the battery system is equivalent to a leakage resistor R3' in the main circuit leakage induction loop 5. At this time, without the influence of PWM pulses, the induced voltage node voltage U of the main circuit leakage induction loop 5 is 2 Greater than the normal voltage node voltage U 0 , and the difference between the two is (U 2 -U 0 )>0; when PWM is high level voltage U 1 When the leakage detection module 4U 1 To U 3 The equivalent resistance between them is (R2'+R2') / / R2'=2 / 3R2'. At this time, the detection node voltage U 3 Close to 3(U 1 -U 0 ) / 5+2(U 2 -U o ) / 3; When PWM is a low level voltage, the leakage detection module 4U 3 To U 0 The equivalent resistance between them is (R2'+R2') / / R2'=2 / 3R2', at this time the voltage of the induced voltage node U3 is 2(U 1 -U 0 ) / 5+2(U 2 -U 0 ) / 3, according to the induced voltage node voltage U formed by the high and low levels of PWM 3 = Low level is 2 (U 1 -U 0 ) / 5+2(U 2 -U0 ) / 3, high level is 3(U 1 -U 0 ) / 5+2(U 2 -U 0 ) / 3, that is, the induced voltage node voltage U 3 The pulse width is consistent with the graph of the PWM pulse transmitting module 3, such as Fig. 9 The leakage curve deviation of the induced voltage node in the working mode detection diagram (U 1 -U 0 ) / 2 upward up and down pulses; that is, when the induced voltage node voltage U 3 When it is on the center line, it is determined that the positive electrode of the battery system is leaking.

[0062] like Figure 5 As shown in the circuit diagram, the positive electrode of the battery system is completely short-circuited to the main circuit leakage induction circuit 5. At this time, without the influence of PWM pulses, the induction voltage node voltage U of the main circuit leakage induction circuit 5 is 2 The voltage U of the node is greater than the normal voltage 0 The difference is (U 2 -U 0 )>>U 1 ; Because (U 2 -U 0 )>>U 1 At this time, the PWM pulse transmitting module 3 is invalid, and the voltage at the induced voltage node U 3 The voltage at is much larger than U 1 , induced voltage node voltage U 3 A straight line graph will be formed, such as Fig. 9 The short-circuit curve straight line diagram in the working mode detection diagram; that is, when the induced voltage node voltage U 3 When it is straight and located on the center line, it is judged that the positive electrode of the battery system is short-circuited.

[0063] like Figure 6 As shown in the circuit diagram, at this time, the negative electrode of the battery system is equivalent to a leakage resistor R3' in the main circuit leakage induction loop 5. At this time, without the influence of PWM pulses, the induced voltage node voltage U 2 Less than the normal voltage node voltage U 0 The difference between the two is (U 2 -U 0 )<0; when PWM is high level voltage U 1 When the leakage detection module 4U 1 To U 3 The equivalent resistance between them is (R2'+R2') / / R2'=2 / 3R2'. At this time, the detection node voltage U 3 Close to 3(U 1 -U0 ) / 5-2(U 2 -U 0 ) / 3; When PWM is a low level voltage, the leakage detection module 4U 3 To U 0 The equivalent resistance between them is (R2'+R2') / / R2'=2 / 3R2'. At this time, the detection node voltage U 3 The voltage is 2(U 1 -U 0 ) / 5-2(U 0 -U 2 ) / 3, according to the induced voltage node voltage U formed by the high and low levels of PWM 3 = Low level 2 (U 1 -U 0 ) / 5-2(U 0 -U 2 ) / 3, high level 3(U 1 -U 0 ) / 5-2(U 0 -U 2 ) / 3, the induced voltage node voltage U 3 It is consistent with the figure of PWM pulse transmission module 3, such as Fig. 9 The leakage curve diagram deviation in the working mode detection diagram (U 1 -U 0 ) / 2 downward pulse; that is, when the voltage U 3 When it is below the neutral line, it is judged that the negative electrode of the battery system is leaking.

[0064] like Figure 7 As shown in the circuit diagram, the negative electrode of the battery system completely short-circuits the induction loop. At this time, without the influence of PWM pulses, the induction voltage node voltage U of the main circuit leakage induction loop 5 is 2 The voltage U of the node is less than the normal voltage 0 The difference is (U 2 -U 0 )<<U 1 ; Because (U 2 -U 0 )<<U 1 At this time, the PWM pulse transmitting module 3 is invalid, and the voltage at the induced voltage node U 3 The voltage at is much smaller than U 0 , induced voltage node voltage U 3 A straight line graph will be formed, such as Fig. 9 The short-circuit curve straight line diagram in the working mode detection diagram; that is, when the induced voltage node voltage U 3 When it is in a straight line and below the center line, it is judged that the negative electrode of the battery system is short-circuited.

[0065] like Figure 8 As shown in the circuit diagram, at this time, without the influence of PWM pulse, the leakage detection module 4 is an independent circuit, not affected by the outside, and the voltage of the induced voltage node U 3 Voltage is equal to (U 1 -U 0 ) / 2 will form a straight line graph, such as Fig. 9 Working mode detection graph (U 1 -U 0 ) / 2 straight line graph. That is, when the voltage at the induced voltage node U 3 When it is straight and located at the center line, it is determined that the induction line of the battery system is broken.

[0066] pass Fig. 9 The voltage waveforms shown in Table 1 can be used to quickly identify the fault point of the battery system 100 .

[0067] Table 1 Working mode

[0068] Positive state Negative state Induction line loop Test results normal normal normal Normal median pulse Leakage normal normal Deviation from median upward pulse Short Circuit normal normal Constant pressure fixed value output normal Leakage normal Deviation from median downward pulse normal Short Circuit normal Constant pressure fixed value output - - Short Circuit Output constant median

[0069] Based on the first embodiment, the present embodiment directly obtains the specific leakage situation of the battery system through the voltage waveform of each node, without the need to perform complex control on the battery system, which can greatly improve the speed and difficulty of detection.

[0070] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A battery system leakage detection system, wherein the battery system is provided with a main circuit, characterized in that: include: Normal circuit module, main circuit leakage induction circuit, PWM pulse transmission module and leakage detection module; The normal circuit module is connected to the battery system, the main circuit, and the PWM pulse transmission module; The normal circuit module is provided with a normal voltage node, the main circuit leakage induction circuit includes: a conductive material wrapped in the outer insulating layer of the main circuit, the main circuit leakage induction circuit is provided with an induction voltage node for detecting whether the main circuit is leaking or short-circuited, and the leakage detection module is provided with a detection node.

2. The battery system leakage detection system according to claim 1, characterized in that: The normal circuit module includes: a first resistor and a second resistor; The positive electrode of the battery system is connected to the negative electrode of the battery system through the first resistor and the second resistor; A connection point between the first resistor and the second resistor is grounded, and a connection point between the first resistor and the second resistor is the normal voltage node.

3. The battery system leakage detection system according to claim 2, characterized in that: The leakage detection module includes: a third resistor, a fourth resistor, a fifth resistor, a first voltage regulator tube, a second voltage regulator tube and an analog / digital converter; The main circuit is connected to the analog / digital converter through the third resistor and the fourth resistor; The main circuit is grounded through the third resistor and the fifth resistor; The third resistor is connected to the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube respectively, the negative electrode of the first voltage regulator tube is connected to the analog / digital converter, and the positive electrode of the second voltage regulator tube is grounded; The connection point between the positive electrode of the first voltage regulator tube and the negative electrode of the second voltage regulator tube is a detection node.

4. The battery system leakage detection system according to claim 3, characterized in that: The main circuit includes: a sixth resistor, a seventh resistor, and an eighth resistor; The PWM pulse transmitting module is connected to the positive electrode of the battery system through the seventh resistor and the sixth resistor; The negative electrode of the battery system is connected to the third resistor via the eighth resistor; The positive electrode of the battery system is connected to the negative electrode of the battery system through the sixth resistor and the eighth resistor; A connection point between the sixth resistor and the eighth resistor is the induced voltage node.

5. The battery system leakage detection system according to claim 4, characterized in that: The resistance values ​​of the first resistor, the second resistor, the sixth resistor, and the eighth resistor are equal; the resistance values ​​of the third resistor, the fourth resistor, the fifth resistor, and the seventh resistor are equal; The normal circuit module is connected to the main loop leakage induction circuit through a switch.

6. A battery system leakage detection method, characterized in that: Applied to the leakage detection system according to any one of claims 1 to 5, the battery system leakage detection method comprises the steps of: When the voltage of the detection node pulses up and down on the neutral line, it is judged that there is no leakage, where the value of the neutral line is Wherein, U1 is the high level voltage of the PWM pulse transmitting module, and U0 is the voltage value of the normal voltage node; When the voltage of the detection node is above the neutral line or below the neutral line, it is determined that the battery system is leaking; When the voltage of the detection node is in a straight line, it is determined that the battery system is short-circuited or the sensing line is broken.

7. The battery system leakage detection method according to claim 6, characterized in that: When the voltage of the detection node is on the neutral line, it is determined that the positive electrode of the battery system is leaking.

8. The battery system leakage detection method according to claim 6, characterized in that: When the voltage of the detection node is below the neutral line, it is determined that the negative electrode of the battery system is leaking.

9. The battery system leakage detection method according to claim 6, characterized in that: When the voltage of the detection node is in a straight line and located on the neutral line, it is determined that the positive electrode of the battery system is short-circuited; When the voltage of the detection node is in a straight line and is below the center line, it is determined that the negative electrode of the battery system is short-circuited.

10. The battery system leakage detection method according to claim 6, characterized in that: When the voltage of the detection node is in a straight line and is located at the neutral line, it is determined that the induction line of the battery system is broken.

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