Online grounding insulation resistance test circuit for energy storage battery pack

Abstract

The utility model discloses an on-line grounding insulation resistance test circuit for an energy storage battery pack, and relates to the technical field of safety detection of an energy storage battery system. The circuit comprises a control voltage, an anode battery sampling unit, a cathode battery sampling unit and a sampling signal processing unit. An electromagnetic relay is replaced by a solid-state relay, so that high-frequency and high-reliability insulation resistance online detection is realized. And the controller selectively accesses different numbers of sampling resistors by controlling the on-off states of the positive electrode sampling switch circuit and the negative electrode sampling switch circuit, so that the resistance value of the sampling circuit is changed. And then, the controller obtains a voltage signal of the sampling circuit through the sampling signal processing unit, and calculates to obtain a grounding insulation resistance value. The utility model has higher reliability and longer service life, and is particularly suitable for high-frequency on-line detection or application occasions of long-life products.

Description

Technical Field

[0001] This utility model relates to the field of safety testing technology for energy storage battery systems, specifically to an online grounding insulation resistance testing circuit for energy storage battery packs. Background Technology

[0002] With the increasing voltage levels of energy storage battery systems, especially when the voltage exceeds 1000V, online monitoring of the system's grounding resistance becomes particularly important to ensure the system's electrical safety. Currently, the commonly used insulation resistance testing method relies on electromagnetic relays continuously switching the connection between the battery's positive and negative terminals and the ground, calculating the grounding resistance by measuring the voltage. However, this method has significant drawbacks: the relay has a limited number of switching cycles, and frequent switching over a long period can lead to contact oxidation, shortening the relay's lifespan. Therefore, it is unsuitable for applications requiring high-frequency online monitoring or long-lifespan products. Utility Model Content

[0003] To overcome the shortcomings of existing technologies, this utility model provides an online grounding insulation resistance test circuit for energy storage battery packs, aiming to achieve high-frequency and high-reliability online insulation resistance detection by using solid-state relays instead of electromagnetic relays.

[0004] The technical solution of this utility model is as follows: An online grounding insulation resistance testing circuit for an energy storage battery pack is provided, comprising a controller, a positive electrode battery sampling unit, a negative electrode battery sampling unit, and a sampling signal processing unit. The positive electrode battery sampling unit includes a positive electrode sampling switch circuit and a positive electrode sampling resistor. The positive electrode sampling resistors are distributed and connected to the positive electrode sampling switch circuit and the positive terminal of the energy storage battery pack. The positive electrode sampling switch circuit is used to control the number of positive electrode sampling resistors connected to the test circuit. The negative electrode battery sampling unit includes a negative electrode sampling switch circuit and a negative electrode sampling resistor. The negative electrode sampling resistors are distributed and connected to the negative electrode sampling switch circuit and the negative terminal of the energy storage battery pack. The negative electrode sampling switch circuit is used to control the number of negative electrode sampling resistors connected to the test circuit. The positive electrode sampling switch circuit, the negative electrode sampling switch circuit, and the sampling signal processing unit are respectively connected to the controller.

[0005] More specifically, the positive sampling resistor includes resistors R1-R4 and resistors R10-R15;

[0006] The positive sampling switch circuit includes a solid-state relay U1, resistors R5, R6, and R7, a capacitor C1, and a transistor Q1.

[0007] The first terminal of the solid-state relay U1 is connected to resistor R7, the second terminal of the solid-state relay U1 is connected to the collector of transistor Q1, the third terminal of the solid-state relay U1 is connected to resistor R11, and the fourth terminal of the solid-state relay U1 is connected to resistor R8; the base of transistor Q1 is connected to the controller through resistor R5 and grounded through resistor R6 and capacitor C1 respectively, and the emitter of transistor Q1 is grounded.

[0008] More specifically, the negative sampling resistor includes resistors R27-R30 and resistors R31-R36;

[0009] The negative sampling switch circuit includes a solid-state relay U4, resistors R24, R25, and R26, a capacitor C13, and a transistor Q3.

[0010] The first terminal of the solid-state relay U4 is connected to resistor R26, the second terminal of the solid-state relay U4 is connected to the collector of transistor Q3, the third terminal of the solid-state relay U4 is connected to resistor R35, and the fourth terminal of the solid-state relay U4 is connected to resistor R9; the base of transistor Q3 is connected to the controller through resistor R24 ​​and grounded through resistor R25 and capacitor C13 respectively, and the emitter of transistor Q1 is grounded.

[0011] More specifically, the sampling signal processing unit includes a first amplification circuit and a second amplification circuit.

[0012] More specifically, the first amplification circuit includes an isolation amplifier U2, resistors R16, R17, and R18, capacitors C2, C3, C4, C5, and C6, inductors L1 and L3, diodes D1 and D2, and Zener diode Z1.

[0013] The first terminal of the isolation amplifier is grounded through capacitor C6, and is connected to diode D1, resistor R16, capacitor C4, and the second terminal of the isolation amplifier through diode D2.

[0014] The third terminal of the isolated amplifier is connected to capacitor C5, resistor R17, and Zener diode Z1, respectively.

[0015] The fourth and fifth terminals of the isolation amplifier are grounded;

[0016] The sixth terminal of the isolation amplifier is connected to the first input terminal of the operational amplifier U1 through resistor R37;

[0017] The seventh terminal of the isolation amplifier is connected to the second input terminal of the operational amplifier U1 through resistor R20;

[0018] The eighth terminal of the isolated amplifier is connected to the power supply terminal through inductor L2, grounded through capacitor C7, and grounded through parallel capacitors C9 and C10.

[0019] More specifically, the second amplifier circuit includes operational amplifier U3, resistors R19, R21, and R38, capacitors C8, C14, and C11.

[0020] The first input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier through a parallel resistor R38 and a capacitor C14. The second input terminal of the operational amplifier U3 is grounded through a parallel resistor R19 and a resistor C8. The output terminal of the operational amplifier is connected to the controller through a resistor R21. The output terminal of the operational amplifier U3 is grounded through a resistor R21 and a capacitor C11.

[0021] More specifically, resistors R8 and R9 are grounded.

[0022] The beneficial effects of this invention are reflected in the fact that by using a solid-state relay instead of a traditional electromagnetic relay, the problem of shortened lifespan caused by contact oxidation is avoided, thereby improving the reliability of online detection. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0024] Figure 1 is a schematic diagram of an online grounding insulation resistance test circuit for an energy storage battery pack provided in this embodiment;

[0025] Figure 2 is a circuit diagram of an online grounding insulation resistance test circuit for an energy storage battery pack provided in this embodiment. Detailed Implementation

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0027] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

[0028] This embodiment provides an online grounding insulation resistance testing circuit for energy storage battery packs, such as... Figure 1As shown, it mainly includes a controller, a positive electrode battery sampling unit, a negative electrode battery sampling unit, and a sampling signal processing unit.

[0029] In this embodiment, as Figure 2 As shown, the positive electrode battery sampling unit includes a positive electrode sampling switch circuit and a positive electrode sampling resistor. The positive electrode sampling resistor consists of resistors R1-R4 and resistors R10-R15, which are connected to the positive terminal of the energy storage battery pack through the positive electrode sampling switch circuit. The positive electrode sampling switch circuit is used to control the number of positive electrode sampling resistors connected to the test circuit, and specifically includes a solid-state relay U1, resistors R5, R6, and R7, a capacitor C1, and a transistor Q1. The first terminal of the solid-state relay U1 is connected to resistor R7, the second terminal is connected to the collector of transistor Q1, the third terminal is connected to resistor R11, and the fourth terminal is connected to resistor R8; the base of transistor Q1 is connected to the controller through resistor R5, and is grounded through resistor R6 and capacitor C1 respectively, and the emitter of transistor Q1 is grounded.

[0030] In this embodiment, as Figure 2 As shown, the negative electrode battery sampling unit includes a negative electrode sampling switch circuit and a negative electrode sampling resistor. The negative electrode sampling resistor consists of resistors R27-R30 and resistors R31-R36, which are connected to the negative terminal of the energy storage battery pack through the negative electrode sampling switch circuit. The negative electrode sampling switch circuit is used to control the number of negative electrode sampling resistors connected to the test circuit, and specifically includes a solid-state relay U4, resistors R24, R25, and R26, a capacitor C13, and a transistor Q3. The first terminal of the solid-state relay U4 is connected to resistor R26, the second terminal is connected to the collector of transistor Q3, the third terminal is connected to resistor R35, and the fourth terminal is connected to resistor R9; the base of transistor Q3 is connected to the controller through resistor R24, and is grounded through resistor R25 and capacitor C13 respectively, and the emitter of transistor Q3 is grounded.

[0031] In this embodiment, as Figure 2As shown, the sampling signal processing unit includes a first amplifier circuit and a second amplifier circuit. The first amplifier circuit is used for isolating and differentially amplifying the sampling signal, and includes an isolation amplifier U2, resistors R16, R17, and R18, capacitors C2, C3, C4, C5, and C6, inductors L1 and L3, diodes D1 and D2, and a Zener diode Z1. The specific connection method is as follows: The first terminal of the isolation amplifier U2 is grounded through capacitor C6, and connected to diode D1, resistor R16, capacitor C4, and the second terminal of the isolation amplifier through diode D2; the third terminal of the isolation amplifier U2 is connected to capacitor C5, resistor R17, and Zener diode Z1; the fourth and fifth terminals of the isolation amplifier U2 are grounded; the sixth terminal of the isolation amplifier U2 is connected to the first input terminal of operational amplifier U1 through resistor R37; the seventh terminal of the isolation amplifier U2 is connected to the second input terminal of operational amplifier U1 through resistor R20; the eighth terminal of the isolation amplifier U2 is connected to the power supply terminal through inductor L2, and grounded through capacitor C7, parallel capacitor C9, and capacitor C10.

[0032] In this embodiment, as Figure 2 As shown, the second amplifier circuit converts the differentially amplified analog signal into a digital signal for processing by the controller. The second amplifier circuit includes operational amplifier U3, resistors R19, R21, and R38, and capacitors C8, C14, and C11. Specifically, the first input terminal of operational amplifier U3 is connected to its output terminal via parallel resistor R38 and capacitor C14, forming a feedback circuit; the second input terminal of operational amplifier U3 is grounded via parallel resistor R19 and capacitor C8; the output terminal of operational amplifier U3 is connected to the controller via resistor R21 to output a digital signal; simultaneously, the output terminal of operational amplifier U3 is also grounded via resistor R21 and capacitor C11 to stabilize the output voltage.

[0033] In practical applications, the controller selectively connects different numbers of sampling resistors by controlling the switching states of the positive and negative sampling switch circuits, thereby changing the resistance value of the sampling circuit. Specifically, when it is necessary to detect the insulation resistance of the battery's positive terminal, the controller sends an EARTH_H signal to close the solid-state relay U1, thus changing the sampling resistance value connected to the battery's positive terminal circuit. The system combines the voltage values ​​before and after the change with the sampling resistance to calculate the current values ​​under the two conditions, and then calculates the resistance value between the battery's positive terminal and ground according to Ohm's law. Similarly, when detecting the insulation resistance between the battery's negative terminal and ground, the controller sends an EARTH_L signal to close the solid-state relay U4 and performs a similar calculation process. Then, the controller obtains the voltage signal of the sampling circuit through the sampling signal processing unit. This signal is isolated and differentially output by the isolation amplifier U2, and then converted into a single-ended output by the operational amplifier U3 and sent to the controller's AD converter for calculating the voltage value, and finally obtaining the ground insulation resistance value. Because it uses a solid-state relay instead of an electromagnetic relay, the online grounding insulation resistance test circuit for energy storage battery packs of this invention has higher reliability and longer service life, making it suitable for applications involving high-frequency online testing or long-life products.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A circuit for testing the online grounding insulation resistance of an energy storage battery pack, characterized in that, The system includes a controller, a positive electrode battery sampling unit, a negative electrode battery sampling unit, and a sampling signal processing unit. The positive electrode battery sampling unit includes a positive electrode sampling switch circuit and a positive electrode sampling resistor. The positive electrode sampling resistors are distributed and connected to the positive electrode sampling switch circuit and the positive terminal of the energy storage battery pack. The positive electrode sampling switch circuit controls the number of positive electrode sampling resistors connected to the test circuit. The negative electrode battery sampling unit includes a negative electrode sampling switch circuit and a negative electrode sampling resistor. The negative electrode sampling resistors are distributed and connected to the negative electrode sampling switch circuit and the negative terminal of the energy storage battery pack. The negative electrode sampling switch circuit controls the number of negative electrode sampling resistors connected to the test circuit. The positive electrode sampling switch circuit, the negative electrode sampling switch circuit, and the sampling signal processing unit are all connected to the controller.

2. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 1, characterized in that, The positive sampling resistor includes resistors R1-R4 and resistors R10-R15; The positive sampling switch circuit includes a solid-state relay U1, resistors R5, R6, and R7, a capacitor C1, and a transistor Q1. The first terminal of the solid-state relay U1 is connected to resistor R7, the second terminal of the solid-state relay U1 is connected to the collector of transistor Q1, the third terminal of the solid-state relay U1 is connected to resistor R11, and the fourth terminal of the solid-state relay U1 is connected to resistor R8; the base of transistor Q1 is connected to the controller through resistor R5 and grounded through resistor R6 and capacitor C1 respectively, and the emitter of transistor Q1 is grounded.

3. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 2, characterized in that, The negative sampling resistor includes resistors R27-R30 and resistors R31-R36; The negative sampling switch circuit includes a solid-state relay U4, resistors R24, R25, and R26, a capacitor C13, and a transistor Q3. The first terminal of the solid-state relay U4 is connected to resistor R26, the second terminal of the solid-state relay U4 is connected to the collector of transistor Q3, the third terminal of the solid-state relay U4 is connected to resistor R35, and the fourth terminal of the solid-state relay U4 is connected to resistor R9; the base of transistor Q3 is connected to the controller through resistor R24 ​​and grounded through resistor R25 and capacitor C13 respectively, and the emitter of transistor Q1 is grounded.

4. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 1, characterized in that, The sampling signal processing unit includes a first amplifier circuit and a second amplifier circuit.

5. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 4, characterized in that, The first amplifier circuit includes an isolation amplifier U2, resistors R16, R17, and R18, capacitors C2, C3, C4, C5, and C6, inductors L1 and L3, diodes D1 and D2, and Zener diode Z1. The first terminal of the isolation amplifier is grounded through capacitor C6, and is connected to diode D1, resistor R16, capacitor C4, and the second terminal of the isolation amplifier through diode D2. The third terminal of the isolated amplifier is connected to capacitor C5, resistor R17, and Zener diode Z1, respectively. The fourth and fifth terminals of the isolation amplifier are grounded; The sixth terminal of the isolation amplifier is connected to the first input terminal of the operational amplifier U1 through resistor R37; The seventh terminal of the isolation amplifier is connected to the second input terminal of the operational amplifier U1 through resistor R20; The eighth terminal of the isolated amplifier is connected to the power supply terminal through inductor L2, grounded through capacitor C7, and grounded through parallel capacitors C9 and C10.

6. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 4, characterized in that, The second amplifier circuit includes operational amplifier U3, resistors R19, R21, and R38, capacitors C8, C14, and C11; The first input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier through a parallel resistor R38 and a capacitor C14. The second input terminal of the operational amplifier U3 is grounded through a parallel resistor R19 and a resistor C8. The output terminal of the operational amplifier is connected to the controller through a resistor R21. The output terminal of the operational amplifier U3 is grounded through a resistor R21 and a capacitor C11.

7. The online grounding insulation resistance test circuit for an energy storage battery pack according to claim 3, characterized in that, Resistors R8 and R9 are grounded.

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