Battery management system
By introducing a pre-discharge circuit and an anti-backflow circuit into the battery management system, the problem of high current damage when a capacitive load is connected is solved, and the circuit and equipment are protected.
Patent Information
- Application Number
- CN202422550142.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-10-22
AI Technical Summary
Existing battery management systems are prone to instantaneous ultra-large current discharge when connected to capacitive loads, damaging electronic components such as MOS tubes, relays or contactors.
A pre-discharge circuit and an anti-backflow circuit are used, and the controller controls the circuit composed of a current-limiting resistor and a MOS tube to prevent high current damage when a capacitive load is connected.
It effectively prevents the damage to circuits and equipment caused by large current when capacitive loads are connected, and protects the components of the battery management system.
Smart Images
Figure CN223309617U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of battery management, and in particular to a battery management system. Background Art
[0002] The loads of existing battery management systems are basically a mixture of resistive, inductive, and capacitive loads. When a capacitive load is connected to the system, an instantaneous ultra-large current discharge (similar to a short circuit) will be generated, which can easily cause the MOS tubes, relays, or contactors in the battery management system's output circuit to burn or melt, resulting in a fatal fault that cannot be cut off. Summary of the Invention
[0003] The purpose of the embodiments of the present application is to provide a battery management system to solve the above technical problems.
[0004] A battery management system includes a first controller, a battery pack, a pre-discharge circuit and a load circuit connected to the positive terminal of the battery pack in sequence;
[0005] When the capacitive load in the load circuit is connected to the battery management system, the first controller is used to control the pre-discharge circuit to connect to the battery management system to perform charging current limiting protection on the load circuit.
[0006] In one embodiment, the battery management system further includes a second controller, which is configured to control the output circuit of the capacitive load to be connected after determining that the pre-discharge circuit has been operating for a preset time period.
[0007] In one embodiment, the battery management system further includes a third controller, and the third controller is configured to control the output loop of the load circuit to be connected when it is determined that the voltage of the capacitive load reaches a preset voltage threshold.
[0008] In one embodiment, the preset voltage threshold is 80% of the maximum operating voltage of the battery management system.
[0009] In one embodiment, the pre-discharge circuit includes a current limiting resistor circuit.
[0010] In one embodiment, the pre-discharge circuit further includes an anti-backflow circuit connected between the current limiting resistor circuit and the capacitive load.
[0011] In one embodiment, the current limiting resistor circuit is composed of a plurality of resistors connected in parallel.
[0012] In one embodiment, the anti-backfeed circuit includes a first MOS transistor and a second MOS transistor connected in sequence, the source of the first MOS transistor is connected to the source of the second MOS transistor, and the gate of the first MOS transistor is connected to the gate of the second MOS transistor and then connected to the first controller.
[0013] In one embodiment, a first diode is connected between the source of the first MOS transistor and the drain of the first MOS transistor, and a second diode is connected between the source of the second MOS transistor and the drain of the second MOS transistor.
[0014] In one embodiment, the load circuit further includes a resistive load and / or an inductive load.
[0015] Through the battery management system provided in this application, when a capacitive load in the load circuit is connected to the battery management system, the first controller controls the pre-discharge circuit to connect to the battery management system to perform charging current limiting protection on the load circuit to prevent the large current generated by the capacitive load when the load is suddenly connected from damaging the circuit and equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 A first structural diagram of a battery management system provided in an embodiment of the present application;
[0017] Figure 2 This is a second structural diagram of the battery management system provided in an embodiment of the present application. DETAILED DESCRIPTION
[0018] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0019] This application embodiment provides a battery management system, see Figure 1 Shown, including:
[0020] A first controller 11, a battery pack 12, a pre-discharge circuit 13 and a load circuit 14 connected to the positive end of the battery pack 12 in sequence; when the capacitive load in the load circuit is connected to the battery management system, the first controller is used to control the pre-discharge circuit to connect to the battery management system to perform charging current limiting protection on the load circuit.
[0021] The pre-discharge circuit in the embodiment of the present application is used to limit the charging current of the capacitive load when the capacitive load is connected to the battery management system, which can prevent the large current generated by the capacitive load when the load is suddenly connected from damaging the circuit and equipment.
[0022] Furthermore, the pre-discharge circuit in the embodiment of the present application includes a current-limiting resistor circuit. In other words, current limiting can be achieved through resistors. Specifically, the current-limiting resistor circuit is composed of multiple resistors connected in parallel. The resistors here can be high-power current-limiting resistors, which can be composed of seven 200Ω / 50W high-power resistors connected in parallel, with a resistance of 28.57Ω after parallel connection.
[0023] The battery management system in the embodiment of the present application may further include an anti-backflow circuit connected between the current limiting resistor circuit and the capacitive load to prevent current backflow and damage to the battery pack and electronic components on the positive end side of the battery pack.
[0024] See Figure 2 As shown, the anti-backfeed circuit in the embodiment of the present application may include a first MOS transistor and a second MOS transistor connected in sequence, the source of the first MOS transistor is connected to the source of the second MOS transistor, and the gate of the first MOS transistor is connected to the gate of the second MOS transistor and then connected to the first controller, wherein the first MOS transistor and the second MOS transistor in the embodiment of the present application can both be N-MOS transistors.
[0025] Furthermore, in the embodiment of the present application, a first diode is connected between the source of the first MOS transistor and the drain of the first MOS transistor, and a second diode is connected between the source of the second MOS transistor and the drain of the second MOS transistor.
[0026] When the capacitive load is connected to the battery management system, the first controller can be used to control the pre-discharge circuit to connect to the battery management system. Specifically, the first controller can send a corresponding trigger signal to open the pre-discharge circuit. Otherwise, the first controller can send another trigger signal to close the pre-discharge circuit.
[0027] In some embodiments, the battery management system may further include a second controller, which is used to control the output circuit of the capacitive load to be connected after determining the preset working time of the pre-discharge circuit. The output circuit of the capacitive load mentioned in the embodiments of the present application refers to the load circuit between the output end of the capacitive load and the negative end of the battery pack. The preset time here is usually the charging time for fully charging the capacitive load. For example, if the pre-discharge circuit can complete charging the capacitive load within 20ms, the preset time here can be set to 20ms.
[0028] In some embodiments, the battery management system may further include a third controller configured to control the output circuit of the load circuit to be connected when determining that the voltage of the capacitive load reaches a preset voltage threshold. Exemplarily, the preset voltage threshold is 80% of the maximum operating voltage of the battery management system.
[0029] It should be noted that the first controller, the second controller and the third controller in the embodiment of the present application may be different controllers or the same controller.
[0030] For example, when the capacitance of the capacitive load is 1000uF, since the voltage across the capacitor cannot change suddenly, the voltage across the capacitive load is 0 at the moment of charging, and the capacitor is approximately short-circuited. Assuming that the maximum operating voltage of the system is 325V, ignoring the cable resistance, at the moment the pre-discharge circuit is turned on, its current is 325V / 28.57Ω=11.375A. Assuming the charging time is 20ms, the charging voltage Uc is calculated based on the RC charging time as U×[1-e(-t / (RC))]=325Vx(1-e(-20ms / (28.57Ωx1000uF)))=260V, that is, a pre-discharge of 20ms can increase the output voltage to about 260V, accounting for 80% of the total voltage.
[0031] In the above example, when the capacitive load is charged to 80% and then the actual output loop of the load circuit is opened, no instantaneous large current will be generated to damage the electronic components in the output loop.
[0032] It can be understood that, in practical applications, the load circuit may also include a resistive load and / or an inductive load.
[0033] It should be noted that the diagrams provided in this embodiment are only used to illustrate the basic concept of the present invention. Therefore, the diagrams only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be changed at will, and the component layout type may also be more complex. The structures, proportions, sizes, etc. shown in the drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read. They are not used to limit the conditions for the implementation of the present invention, so they have no technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the effect and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.
[0034] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0035] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.
Claims
1. A battery management system, characterized in that: It includes a first controller, a battery pack, a pre-discharge circuit and a load circuit connected in sequence to the positive terminal of the battery pack; When the capacitive load in the load circuit is connected to the battery management system, the first controller is used to control the pre-discharge circuit to connect to the battery management system to perform charging current limiting protection on the load circuit.
2. The battery management system according to claim 1, wherein: The battery management system further includes a second controller, which is configured to control the output circuit of the capacitive load to be connected after determining that the pre-discharge circuit has been operating for a preset time period.
3. The battery management system according to claim 1, wherein: The battery management system further includes a third controller, which is configured to control the output loop of the load circuit to be connected when it is determined that the voltage of the capacitive load reaches a preset voltage threshold.
4. The battery management system according to claim 3, characterized in that: The preset voltage threshold is 80% of the maximum operating voltage of the battery management system.
5. The battery management system according to claim 1, wherein: The pre-discharge circuit includes a current limiting resistor circuit.
6. The battery management system according to claim 5, characterized in that: The pre-discharge circuit further includes an anti-backflow circuit connected between the current limiting resistor circuit and the capacitive load.
7. The battery management system according to claim 5, characterized in that: The current limiting resistor circuit is composed of a plurality of resistors connected in parallel.
8. The battery management system according to claim 6, wherein: The anti-backfeed circuit includes a first MOS transistor and a second MOS transistor connected in sequence, the source of the first MOS transistor is connected to the source of the second MOS transistor, and the gate of the first MOS transistor is connected to the gate of the second MOS transistor and then connected to the first controller.
9. The battery management system according to claim 8, wherein: A first diode is connected between the source of the first MOS transistor and the drain of the first MOS transistor, and a second diode is connected between the source of the second MOS transistor and the drain of the second MOS transistor.
10. The battery management system according to claim 1, wherein: The load circuit also includes a resistive load and / or an inductive load.