A control circuit, system and method for a power battery circuit

Abstract

The present invention discloses a control circuit, system, and method for a power battery circuit, relating to the field of battery control and management technology, comprising: a capacitance detection circuit and a controller, wherein the capacitance detection circuit is connected in parallel with the negative contactor of the power battery circuit; the controller is connected to the capacitance detection circuit and the negative contactor of the power battery circuit and is configured to: respond to a high-voltage control instruction on the power battery circuit, detect the capacitance of the power battery circuit through the capacitance detection circuit; determine whether the capacitance of the power battery circuit does not exceed a preset threshold; and if so, control the negative contactor to close. When responding to a high-voltage control instruction on the power battery circuit, the present invention first detects the capacitance of the power battery circuit through the capacitance detection circuit, and only controls the negative contactor to close when the capacitance of the power battery circuit does not exceed the preset threshold. This can minimize adhesion failures of the negative contactor and ensure the safety of the power battery circuit and the safety of personnel.

Description

Technical Field

[0001] The present invention relates to the technical field of battery control management, and in particular to a control circuit, system and method for a power battery circuit. Background Art

[0002] During the development of new energy vehicles, different models have different high-voltage architectures. Some models implement a two-part high-voltage power distribution unit: the battery system high-voltage distribution unit (BDU) and the vehicle's all-in-one high-voltage power distribution unit (PDU). The negative contactor is located in the BDU and driven by the battery management system (BMS). The positive contactor and pre-charge contactor are located in the PDU and driven by the PDU.

[0003] This high-voltage architecture presents the following issues: Due to various factors (such as EMC filtering), the X and Y capacitors on the back end of the negative contactor in the all-in-one high-voltage distribution unit can cause excessive superposition. If the BMS directly closes the negative contactor after receiving the power-on command, the high current generated by the charging of the X and Y capacitors can cause adhesion and damage, posing a safety hazard. Summary of the Invention

[0004] Embodiments of the present invention provide a control circuit, system, and method for a power battery circuit to address the technical problem in the related art that, when a large external capacitor is present in an existing power battery circuit, the negative contactor is directly attracted, resulting in a large current shock generated by capacitor charging, which may cause a adhesion failure of the negative contactor.

[0005] In a first aspect, a control circuit for a power battery circuit is provided, comprising:

[0006] A capacitance detection circuit connected in parallel with the negative contactor of the power battery circuit;

[0007] A controller is connected to the capacitance detection circuit and the negative contactor of the power battery circuit and is configured to:

[0008] In response to a high-voltage control instruction on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit;

[0009] Determine whether the capacitance of the power battery circuit does not exceed a preset threshold;

[0010] If so, the negative contactor is controlled to close.

[0011] In some embodiments, the capacitance detection circuit includes a voltage collector, a first controllable switch, a switch control circuit, and a detection resistor. The voltage collector is connected in parallel with the negative contactor of the power battery circuit. The first controllable switch and the detection resistor are connected in series and then connected in parallel with the negative contactor of the power battery circuit. The voltage collector is connected to a controller, and the switch control circuit is connected to the first controllable switch and the controller.

[0012] The step of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by the capacitance detection circuit includes:

[0013] The controller controls the switch control circuit to turn on the first controllable switch, and collects the capacitor voltage of the power battery circuit in real time through the voltage collector;

[0014] The capacitance of the power battery circuit is then calculated based on the capacitance voltage of the power battery circuit collected in real time and the resistance value of the detection resistor.

[0015] In some embodiments, the switch control circuit includes a first resistor, a second resistor, a third resistor, and a second controllable switch.

[0016] In some embodiments, the first controllable switch is a photoelectric coupling switch.

[0017] In some embodiments, the second controllable switch is a MOS transistor.

[0018] In some embodiments, after determining whether the capacitance of the power battery circuit does not exceed a preset threshold, the method further includes:

[0019] If not, report that there is a fault in the power battery circuit.

[0020] In a second aspect, a control system for a power battery circuit is provided, comprising the aforementioned control circuit for the power battery circuit.

[0021] In a third aspect, a method for controlling a power battery circuit is provided, comprising the following steps:

[0022] Responding to the high-voltage control command on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit;

[0023] Determine whether the capacitance of the power battery circuit does not exceed a preset threshold;

[0024] If so, the negative contactor is controlled to close.

[0025] In some embodiments, responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by a capacitance detection circuit includes:

[0026] The switch control circuit of the capacitance detection circuit is controlled to turn on the first controllable switch of the capacitance detection circuit, and the capacitance voltage of the power battery circuit is collected in real time through the voltage collector of the capacitance detection circuit;

[0027] The capacitance of the power battery circuit is then calculated based on the capacitor voltage of the power battery circuit collected in real time and the resistance value of the detection resistor of the capacitance detection circuit.

[0028] In some embodiments, after determining whether the capacitance of the power battery circuit does not exceed a preset threshold, the method further includes:

[0029] If not, report that there is a fault in the power battery circuit.

[0030] The beneficial effects brought about by the technical solution provided by the present invention include:

[0031] Embodiments of the present invention provide a control circuit, system, and method for a power battery circuit. The control circuit includes a capacitance detection circuit and a controller. The capacitance detection circuit is connected in parallel with the negative contactor of the power battery circuit. When responding to a high-voltage control instruction on the power battery circuit, the controller first detects the capacitance of the power battery circuit through the capacitance detection circuit. Only when the capacitance of the power battery circuit does not exceed a preset threshold value is the negative contactor controlled to be attracted. This can minimize adhesion failures of the negative contactor and ensure the safety of the power battery circuit and the safety of personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A circuit diagram of an existing power battery circuit;

[0034] Figure 2 A schematic diagram of a control circuit of a power battery circuit provided by an embodiment of the present invention;

[0035] Figure 3 Another schematic diagram of a control circuit for a power battery circuit provided by an embodiment of the present invention;

[0036] Figure 4 A flow chart of a method for controlling a power battery circuit provided by an embodiment of the present invention;

[0037] Figure 5 The embodiment of the present invention provides Figure 4 Flowchart for implementing step S10;

[0038] Figure 6 Another flow chart of a method for controlling a power battery circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 making creative efforts shall fall within the scope of protection of the present invention.

[0040] An embodiment of the present invention provides a control circuit for a power battery circuit, which can solve the technical problem that when a large external capacitor is present in an existing power battery circuit, the negative contactor is directly attracted, which may cause a large current shock due to capacitor charging and cause a adhesion failure of the negative contactor.

[0041] See also Figure 2 As shown, an embodiment of the present invention provides a control circuit for a power battery circuit, including: a capacitance detection circuit and a controller.

[0042] The capacitance detection circuit is connected in parallel with the negative contactor of the power battery circuit. The controller is connected to the capacitance detection circuit and the negative contactor of the power battery circuit and is configured as follows:

[0043] In response to a high-voltage control instruction on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit;

[0044] Determine whether the capacitance of the power battery circuit does not exceed a preset threshold;

[0045] If so, the negative contactor is controlled to close.

[0046] Specifically, see Figure 3 As shown in the figure, the power battery circuit includes a battery, a positive contactor, a negative contactor and a load, which are connected to form a circuit. The power battery circuit also includes a pre-charge contactor and a pre-charge resistor. The pre-charge resistor and the pre-charge contactor are connected in series and then in parallel with the positive contactor. If there is a capacitor outside the power battery circuit, the relationship between the external capacitor and the power battery circuit can be simplified as follows: Figure 1 As shown in the schematic diagram. Figure 1As shown, the external capacitor includes an X capacitor and a Y capacitor. When the X capacitor and the Y capacitor are large, if the negative contactor is directly attracted, the charging of the X capacitor and the Y capacitor will generate a large current shock, which may cause the negative contactor to have a adhesion failure. Therefore, an embodiment of the present invention adds a capacitance detection circuit. When the controller responds to the high-voltage control instruction on the power battery circuit, it first detects the capacitance of the power battery circuit through the capacitance detection circuit. Only when the capacitance of the power battery circuit does not exceed the preset threshold value, the negative contactor is controlled to be attracted. This can avoid the adhesion failure of the negative contactor as much as possible, ensuring the safety of the power battery circuit and the safety of the staff.

[0047] As an optional implementation, in one embodiment of the invention, see Figure 3 As shown, the capacitance detection circuit includes a voltage collector V1, a first controllable switch U1, a switch control circuit and a detection resistor R L The voltage collector V1 is connected in parallel with the negative contactor of the power battery circuit, and the first controllable switch U1 and the detection resistor R are connected in series. L The voltage collector V1 is then connected in parallel with the negative contactor of the power battery circuit. The switch control circuit is connected to the first controllable switch U1 and the controller. Optionally, the first controllable switch U1 is a photoelectric coupling switch. Photoelectric coupling switches can achieve optical isolation between circuits, eliminate electrical noise and interference, help improve circuit stability and reliability, and ensure accurate signal transmission.

[0048] The step of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by the capacitance detection circuit includes:

[0049] The controller controls the switch control circuit to turn on the first controllable switch U1, and collects the capacitor voltage of the power battery circuit in real time through the voltage collector V1;

[0050] The capacitance of the power battery circuit is then calculated based on the capacitance voltage of the power battery circuit collected in real time and the resistance value RL of the detection resistor.

[0051] Specifically, it is usually required that after the controller receives the high voltage instruction, the negative contactor pull-in time cannot exceed 1s. In order to reduce the capacitive reactance detection current and the detection time requirement cannot be too long, the resistor R L and detection time t are set.

[0052] The relationship between the capacitance voltage Ut of the power battery circuit and time:

[0053] Ut=U0+(Us-U0)*(1-e^(-t / R L C));

[0054] Where: U0 is the initial voltage of the capacitor, in V; Us is the battery voltage, in V; t is the capacitor charging time, in s; R L is the resistance of the detection resistor, in Ω; C is the equivalent capacitance of the X capacitor and the Y capacitor, in F.

[0055] Let U0 = 0V, then: Ut = Us*(1-e^(-t / RC)); Generally, the capacitance of the power battery circuit is required to be no more than 50uF. Assuming the detection time is 300ms, R L =20kΩ, and substituting into the above formula, we get Ut = 0.26Us. That is, 300ms after the command is issued, if Ut ≤ 0.26Us, the capacitance of the power battery circuit is considered to exceed the preset threshold, and the negative contactor is prohibited from closing. If Ut > 0.26Us, the capacitance of the power battery circuit is considered to meet the requirement, and the negative contactor can be directly closed.

[0056] As an optional implementation, in one embodiment of the invention, see Figure 2 As shown, the switch control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and a second controllable switch Q1. Optionally, the second controllable switch Q1 is a MOS transistor. MOS transistors can control the flow of current based on the control voltage of an input signal, thereby realizing the switching function of the circuit, which is simple and practical.

[0057] A first end of the first resistor is connected to the pull-up voltage, and a second end of the first resistor is connected to the first end of the first controllable switch U1;

[0058] A first end of the second controllable switch Q1 is connected to a second end of the first controllable switch U1, and a second end of the second controllable switch Q1 is grounded;

[0059] A first end of the second resistor R2 is connected to the controller, and a second end of the second resistor R2 is connected to a third end of the second controllable switch Q1;

[0060] A first end of the third resistor R3 is connected to the third end of the second controllable switch Q1 , and a second end of the third resistor R3 is grounded.

[0061] like Figure 3 As shown, when the controller outputs a high level, the second controllable switch Q1 is turned on, thereby turning on the left side of the first controllable switch U1, and the capacitor of the power battery circuit begins to charge, thereby calculating the capacitance of the power battery circuit. The circuit structure is simple and reliable.

[0062] As an optional implementation manner, in one embodiment of the invention, after determining whether the capacitance of the power battery circuit does not exceed a preset threshold, the method includes:

[0063] If not, report that there is a fault in the power battery circuit.

[0064] As mentioned above, when the capacitance of the power battery circuit is required not to exceed 50uF, assuming the detection time is 300ms, 300ms after the instruction is issued, if Ut≤0.26Us, it is considered that the capacitance of the power battery circuit exceeds the preset threshold, and the negative contactor is prohibited from closing. At the same time, a fault of excessive capacitive reactance in the power battery circuit is reported to the staff to ensure the safety of the power battery circuit and the staff.

[0065] An embodiment of the present invention further provides a control system for a power battery circuit, comprising the aforementioned control circuit for the power battery circuit. The control circuit comprises: a capacitance detection circuit and a controller.

[0066] The capacitance detection circuit is connected in parallel with the negative contactor of the power battery circuit. The controller is connected to the capacitance detection circuit and the negative contactor of the power battery circuit and is configured as follows:

[0067] In response to a high-voltage control instruction on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit;

[0068] Determine whether the capacitance of the power battery circuit does not exceed a preset threshold;

[0069] If so, the negative contactor is controlled to close.

[0070] Specifically, see Figure 3 As shown in the figure, the power battery circuit includes a battery, a positive contactor, a negative contactor and a load, which are connected to form a circuit. The power battery circuit also includes a pre-charge contactor and a pre-charge resistor. The pre-charge resistor and the pre-charge contactor are connected in series and then in parallel with the positive contactor. If there is a capacitor outside the power battery circuit, the relationship between the external capacitor and the power battery circuit can be simplified as follows: Figure 1 As shown in the schematic diagram. Figure 1 As shown, the external capacitor includes an X capacitor and a Y capacitor. When the X capacitor and the Y capacitor are large, if the negative contactor is directly attracted, the charging of the X capacitor and the Y capacitor will generate a large current shock, which may cause the negative contactor to have a adhesion failure. Therefore, an embodiment of the present invention adds a capacitance detection circuit. When the controller responds to the high-voltage control instruction on the power battery circuit, it first detects the capacitance of the power battery circuit through the capacitance detection circuit. Only when the capacitance of the power battery circuit does not exceed the preset threshold value, the negative contactor is controlled to be attracted. This can avoid the adhesion failure of the negative contactor as much as possible, ensuring the safety of the power battery circuit and the safety of the staff.

[0071] As an optional implementation, in one embodiment of the invention, see Figure 3As shown, the capacitance detection circuit includes a voltage collector V1, a first controllable switch U1, a switch control circuit and a detection resistor R L The voltage collector V1, the first controllable switch U1, and the detection resistor R are connected in series. L The voltage collector V1 is then connected in parallel with the negative contactor of the power battery circuit. The switch control circuit is connected to the first controllable switch U1 and the controller. Optionally, the first controllable switch U1 is a photoelectric coupling switch. Photoelectric coupling switches can achieve optical isolation between circuits, eliminate electrical noise and interference, help improve circuit stability and reliability, and ensure accurate signal transmission.

[0072] The step of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by the capacitance detection circuit includes:

[0073] The controller controls the switch control circuit to turn on the first controllable switch U1, and collects the capacitor voltage of the power battery circuit in real time through the voltage collector V1;

[0074] The capacitance of the power battery circuit is then calculated based on the capacitance voltage of the power battery circuit collected in real time and the resistance value RL of the detection resistor.

[0075] Specifically, it is usually required that after the controller receives the high voltage instruction, the negative contactor pull-in time cannot exceed 1s. In order to reduce the capacitive reactance detection current and the detection time requirement cannot be too long, the resistor R L and detection time t are set.

[0076] The relationship between the capacitance voltage Ut of the power battery circuit and time:

[0077] Ut=U0+(Us-U0)*(1-e^(-t / R L C));

[0078] Where: U0 is the initial voltage of the capacitor, in V; Us is the battery voltage, in V; t is the capacitor charging time, in s; R L is the resistance of the detection resistor, in Ω; C is the equivalent capacitance of the X capacitor and the Y capacitor, in F.

[0079] Let U0 = 0V, then: Ut = Us*(1-e^(-t / RC)); Generally, the capacitance of the power battery circuit is required to be no more than 50uF. Assuming the detection time is 300ms, R L=20kΩ, and substituting into the above formula, we get Ut = 0.26Us. That is, 300ms after the command is issued, if Ut ≤ 0.26Us, the capacitance of the power battery circuit is considered to exceed the preset threshold, and the negative contactor is prohibited from closing. If Ut > 0.26Us, the capacitance of the power battery circuit is considered to meet the requirement, and the negative contactor can be directly closed.

[0080] As an optional implementation, in one embodiment of the invention, see Figure 2 As shown, the switch control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and a second controllable switch Q1. Optionally, the second controllable switch Q1 is a MOS transistor. MOS transistors can control the flow of current based on the control voltage of an input signal, thereby realizing the switching function of the circuit, which is simple and practical.

[0081] A first end of the first resistor is connected to the pull-up voltage, and a second end of the first resistor is connected to the first end of the first controllable switch U1;

[0082] A first end of the second controllable switch Q1 is connected to a second end of the first controllable switch U1, and a second end of the second controllable switch Q1 is grounded;

[0083] A first end of the second resistor R2 is connected to the controller, and a second end of the second resistor R2 is connected to a third end of the second controllable switch Q1;

[0084] A first end of the third resistor R3 is connected to the third end of the second controllable switch Q1 , and a second end of the third resistor R3 is grounded.

[0085] like Figure 3 As shown, when the controller outputs a high level, the second controllable switch Q1 is turned on, thereby turning on the left side of the first controllable switch U1, and the capacitor of the power battery circuit begins to charge, thereby calculating the capacitance of the power battery circuit. The circuit structure is simple and reliable.

[0086] See also Figure 4 As shown, an embodiment of the present invention further provides a method for controlling a power battery circuit, comprising the following steps:

[0087] Step S10, responding to the high-voltage control instruction on the power battery circuit, detecting the capacitance of the power battery circuit through the capacitance detection circuit;

[0088] Step S20, determining whether the capacitance of the power battery circuit does not exceed a preset threshold;

[0089] Step S30: If yes, control the negative contactor to be closed.

[0090] The control method for the power battery circuit of an embodiment of the present invention, when responding to a high-voltage control instruction on the power battery circuit, first detects the capacitance of the power battery circuit through the capacitance detection circuit. Only when the capacitance of the power battery circuit does not exceed a preset threshold value, the negative contactor is controlled to be attracted. This can minimize adhesion failures of the negative contactor and ensure the safety of the power battery circuit and personnel.

[0091] As an optional implementation, in one embodiment of the invention, see Figure 5 As shown, the method of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit through the capacitance detection circuit includes:

[0092] Step S101, controlling the switch control circuit of the capacitance detection circuit to turn on the first controllable switch of the capacitance detection circuit, and collecting the capacitance voltage of the power battery circuit in real time through the voltage collector of the capacitance detection circuit;

[0093] In step S102 , the capacitance of the power battery circuit is calculated based on the capacitance voltage of the power battery circuit collected in real time and the detection resistance of the capacitance detection circuit.

[0094] Specifically, it is usually required that after the controller receives the high voltage instruction, the negative contactor pull-in time cannot exceed 1s. In order to reduce the capacitive reactance detection current and the detection time requirement cannot be too long, the resistor R L and detection time t are set.

[0095] The relationship between the capacitance voltage Ut of the power battery circuit and time:

[0096] Ut=U0+(Us-U0)*(1-e^(-t / R L C));

[0097] Where: U0 is the initial voltage of the capacitor, in V; Us is the battery voltage, in V; t is the capacitor charging time, in s; R L is the resistance of the detection resistor, in Ω; C is the equivalent capacitance of the X capacitor and the Y capacitor, in F.

[0098] Let U0 = 0V, then: Ut = Us*(1-e^(-t / RC)); Generally, the capacitance of the power battery circuit is required to be no more than 50uF. Assuming the detection time is 300ms, R L =20kΩ, and substituting into the above formula, we get Ut = 0.26Us. That is, 300ms after the command is issued, if Ut ≤ 0.26Us, the capacitance of the power battery circuit is considered to exceed the preset threshold, and the negative contactor is prohibited from closing. If Ut > 0.26Us, the capacitance of the power battery circuit is considered to meet the requirement, and the negative contactor can be directly closed.

[0099] As an optional implementation, in one embodiment of the invention, see Figure 6 As shown, after determining whether the capacitance of the power battery circuit does not exceed the preset threshold, the following steps are included:

[0100] Step S40: If not, report that there is a fault in the power battery circuit.

[0101] As mentioned above, when the capacitance of the power battery circuit is required not to exceed 50uF, assuming the detection time is 300ms, 300ms after the instruction is issued, if Ut≤0.26Us, it is considered that the capacitance of the power battery circuit exceeds the preset threshold, and the negative contactor is prohibited from closing. At the same time, a fault of excessive capacitive reactance in the power battery circuit is reported to the staff to ensure the safety of the power battery circuit and the staff.

[0102] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0103] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0104] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features of the present invention.

Claims

1. A control circuit for a power battery circuit, characterized in that: include: A capacitance detection circuit connected in parallel with the negative contactor of the power battery circuit; A controller is connected to the capacitance detection circuit and the negative contactor of the power battery circuit and is configured to: In response to a high-voltage control instruction on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit; Determine whether the capacitance of the power battery circuit does not exceed a preset threshold; If so, control the negative contactor to close; The capacitance detection circuit includes a voltage collector, a first controllable switch, a switch control circuit and a detection resistor. The voltage collector is connected in parallel with the negative contactor of the power battery circuit. The first controllable switch and the detection resistor are connected in series and then connected in parallel with the negative contactor of the power battery circuit. The voltage collector is connected to a controller, and the switch control circuit is connected to the first controllable switch and the controller. The step of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by the capacitance detection circuit includes: The controller controls the switch control circuit to turn on the first controllable switch, and collects the capacitor voltage of the power battery circuit in real time through the voltage collector; The capacitance of the power battery circuit is then calculated based on the capacitance voltage of the power battery circuit collected in real time and the resistance value of the detection resistor.

2. The control circuit of the power battery circuit according to claim 1, characterized in that: The switch control circuit includes a first resistor, a second resistor, a third resistor and a second controllable switch.

3. The control circuit of the power battery circuit according to claim 2, characterized in that: The first controllable switch is a photoelectric coupling switch.

4. The control circuit of the power battery circuit according to claim 2, characterized in that: The second controllable switch is a MOS tube.

5. The control circuit of the power battery circuit according to claim 1, characterized in that: After determining whether the capacitance of the power battery circuit does not exceed the preset threshold, the method includes: If not, report that there is a fault in the power battery circuit.

6. A control system for a power battery circuit, characterized in that: A control circuit comprising the power battery circuit according to any one of claims 1 to 5.

7. A method for controlling a power battery circuit, using the control circuit of the power battery circuit according to claim 1, characterized in that: The following steps are involved: Responding to the high-voltage control command on the power battery circuit, the capacitance of the power battery circuit is detected by the capacitance detection circuit; Determine whether the capacitance of the power battery circuit does not exceed a preset threshold; If so, control the negative contactor to close; The method of responding to the high-voltage control instruction on the power battery circuit and detecting the capacitance of the power battery circuit by the capacitance detection circuit includes: The switch control circuit of the capacitance detection circuit is controlled to turn on the first controllable switch of the capacitance detection circuit, and the capacitance voltage of the power battery circuit is collected in real time through the voltage collector of the capacitance detection circuit; The capacitance of the power battery circuit is then calculated based on the capacitor voltage of the power battery circuit collected in real time and the resistance value of the detection resistor of the capacitance detection circuit.

8. The method for controlling a power battery circuit according to claim 7, characterized in that: After determining whether the capacitance of the power battery circuit does not exceed the preset threshold, the method includes: If not, report that there is a fault in the power battery circuit.

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