BMS input end circuit system and automobile

Abstract

The utility model provides a BMS input end circuit system comprising a BMS circuit which comprises a BMS module circuit, and an external power supply and a battery pack which are connected with the BMS module circuit; the positive phase proportion operation amplification circuit is connected between the external power supply and the battery pack and the power supply input end of the BMS module circuit; the normal phase proportion operational amplifier circuit comprises an operational amplifier, a first diode, an amplification gain module and a second diode; the positive power end of the operational amplifier is connected with the negative electrode of the first diode. The positive electrode of the first diode is connected with an external power supply. The negative power supply end is grounded; the positive-phase input end is connected with the anode of the battery pack; the negative phase input end is connected to the amplification gain module; the amplification gain module is connected in parallel between the grounding end and the output end; the output end is connected with the power supply input end of the BMS module circuit, and the BMS module circuit is connected with the negative electrode of the battery pack and is grounded; the anode of the second diode is connected to the anode of the battery pack, and the cathode is connected to the output end.

Description

Technical Field

[0001] This utility model relates to the field of automotive power systems, and more particularly to a BMS input circuit system and an automobile. Background Technology

[0002] With the development of new energy vehicles, the energy density of 12V lithium-ion battery packs needs to be continuously improved to support the increasing low-voltage energy consumption demands within vehicles. To increase the effective energy storage of the battery pack, reducing its own energy consumption has also become crucial. Simultaneously, the increase in in-vehicle loads, especially inductive loads, can lead to significant surge impacts during load switching, load drops, or even short circuits, potentially threatening the safety and reliability of components within the battery management system (BMS).

[0003] In existing 12VBMS designs, an RC filter circuit is typically used at the input to protect against external surge impacts. This design reduces the impact of surge current on the BMS by connecting a resistor in series and a capacitor in parallel at the input.

[0004] However, this RC filter design has some significant drawbacks. First, the series connection of the resistor at the input increases the line voltage drop, causing the BMS operating current to be supplied by the battery pack rather than an external DC-DC converter in most cases, which increases the overall energy consumption of the battery pack. Second, the long-term series connection of the resistor generates heat, leading to an increase in the BMS temperature and thus increasing the failure rate of the devices. Furthermore, electrolytic capacitors have problems such as large board space requirements, difficulty in installation, high equivalent series resistance (ESR), large self-generated heat, and rapid capacitance decay, further limiting their application effectiveness in BMS. Utility Model Content

[0005] To overcome the aforementioned technical deficiencies, the purpose of this invention is to provide a BMS input circuit system for automobiles. An operational amplifier circuit with a non-inverting proportional amplifier is constructed to isolate the external power supply and battery power supply, avoiding the impact of surge damage on the BMS module circuitry. The external power supply powers the operational amplifier, and the battery pack is connected to the high-impedance input terminal, with diodes used to achieve power switching. This ensures that when the external voltage is higher than the battery voltage, the BMS primarily receives power from the external source, reducing battery power consumption and improving system robustness.

[0006] This utility model discloses a BMS input terminal circuit system, including:

[0007] BMS circuit, the BMS circuit includes BMS module circuit, and external power supply and battery pack connected to the BMS module circuit;

[0008] It also includes: a non-inverting operational amplifier circuit, connected between the external power supply and the power input terminal of the battery pack and the BMS module circuit; the non-inverting operational amplifier circuit includes:

[0009] Operational amplifier, first diode, amplification gain module, and second diode;

[0010] The positive power supply terminal of the operational amplifier is connected to the negative terminal of the first diode, and the positive terminal of the first diode is connected to the external power supply; the negative power supply terminal is grounded; the positive input terminal is connected to the positive terminal of the battery pack; the negative input terminal is connected to the amplification gain module; the amplification gain module is connected in parallel between the ground terminal and the output terminal; the output terminal is connected to the power supply input terminal of the BMS module circuit, and the BMS module circuit is connected to the negative terminal of the battery pack and grounded.

[0011] The positive terminal of the second diode is connected to the positive terminal of the battery pack, and the negative terminal is connected to the output terminal.

[0012] Optionally, a third diode is also included, the anode of which is connected to the positive terminal of the battery pack, and the cathode of which is connected to the positive input terminal.

[0013] Optionally, the amplification gain module includes an input resistor and a feedback resistor;

[0014] The input resistor and the feedback resistor are connected in series and then connected in parallel between the output terminal and the ground terminal; the feedback resistor is connected to the output terminal and the input resistor is connected to the ground terminal; the negative phase input terminal is connected between the input resistor and the feedback resistor.

[0015] Optionally, the battery pack outputs a battery voltage signal to the non-inverting input terminal, and the operational amplifier amplifies the battery voltage signal received at the non-inverting input terminal to form a battery voltage amplified signal. The voltage value of the battery voltage amplified signal is:

[0016] V = V B+ *(1+R f / R1);

[0017] Among them, R f R1 is the resistance value of the feedback resistor; R2 is the resistance value of the input resistor; = V B+ This is the voltage value of the voltage signal input to the non-inverting input terminal.

[0018] Optionally, the external power supply is a DC / DC module or a load.

[0019] Optionally, the load may include a motor.

[0020] Optionally, the voltage value of the DC / DC module is 12V.

[0021] A vehicle is also disclosed, including the BMS input circuit system described in any of the foregoing embodiments.

[0022] Compared with existing technologies, the above technical solution has the following advantages:

[0023] 1. An external power supply powers the operational amplifier, and the battery pack is connected to the high-impedance input terminal. Power switching is achieved using diodes. When the external voltage is higher than the battery voltage, the BMS primarily draws power from the external source, reducing battery consumption under normal operating conditions and improving system efficiency.

[0024] 2. Enhanced system robustness: By isolating the external power supply from the BMS input power supply, surge impacts caused by external load changes and other factors are effectively prevented, thereby enhancing the system's robustness.

[0025] 3. The design improvements increased the probability of the system passing EMC tests and enhanced electromagnetic compatibility.

[0026] 4. Reduced energy loss and device failure: It avoids energy loss and resistor heating caused by line resistance, reduces the probability of device failure, and improves system reliability.

[0027] 5. Eliminating electrolytic capacitors simplifies circuit design, reduces circuit footprint, and improves overall system performance. Attached Figure Description

[0028] Figure 1 A schematic diagram of the BMS input terminal circuit system according to an embodiment of this utility model;

[0029] Figure 2 The waveform diagrams of voltage in the circuit under different conditions according to an embodiment of this utility model;

[0030] Figure 3 The waveform diagrams of voltage in the circuit under different conditions according to an embodiment of this utility model;

[0031] Figure 4 The waveform diagrams of voltage in the circuit under different conditions according to an embodiment of this utility model;

[0032] Figure 5 The waveform diagrams of voltage in the circuit under different conditions according to an embodiment of this utility model;

[0033] Figure label:

[0034] 1-Battery pack;

[0035] 2-Non-inverting operational amplifier circuit;

[0036] 21-Operational amplifier;

[0037] 22-Gain Module;

[0038] 3-BMS module circuit;

[0039] 4. External power supply. Detailed Implementation

[0040] The advantages of this utility model are further illustrated below with reference to the accompanying drawings and specific embodiments.

[0041] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0042] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0043] In the description of this utility model, it should be understood that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0044] In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0045] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrating this invention and has no specific meaning in itself. Therefore, "module" and "part" can be used interchangeably.

[0046] This utility model provides a BMS input circuit system, see reference. Figure 1 The diagram shows a schematic of a BMS input circuit system conforming to this utility model.

[0047] The BMS input circuit system includes: BMS circuit and positive phase proportional operational amplifier circuit 2.

[0048] The BMS circuit includes a BMS module circuit 3, and an external power supply 4 and a battery pack 1 connected to the BMS module circuit 3.

[0049] BMS module circuit 3 is used for battery management.

[0050] External power supply 4 and battery pack 1 are used to power the BMS module circuit 3, maintaining its normal operation. External power supply 4 is a DC / DC module or load, used to output voltage T30; the voltage value of the DC / DC module is 12V. The load is a low-voltage load, including inductive loads such as motors, providing voltage T30. Battery pack 1 consists of several battery cells; it is used to output the voltage signal "Battery". + .

[0051] The BMS module circuit 3 and the positive phase proportional operational amplifier circuit 2 form the vehicle BMS. The positive phase proportional operational amplifier circuit 2 is connected between the external power supply 4 and the power input terminal of the BMS module circuit 3. The positive phase proportional operational amplifier circuit 2 includes: a first diode D1, a second diode D2, an operational amplifier 21, and an amplification gain module 22.

[0052] The positive power supply terminal of the operational amplifier 21 is connected to the negative terminal of the first diode D1, and the positive terminal of the first diode D1 is connected to the external power supply 4; the negative power supply terminal is grounded; the non-inverting input terminal is connected to the positive terminal of the battery pack 1; the negative-inverting input terminal is connected to the amplification gain module 22; the amplification gain module 22 is connected in parallel between the ground terminal and the output terminal; the output terminal is connected to the power supply input terminal of the BMS module circuit 3, and the BMS module circuit 3 is connected to the negative terminal of the battery pack 1 and grounded. When the voltage of the external power supply 4 is higher than the voltage of the battery pack 1, the external power supply 4 provides the operating voltage for the operational amplifier 21. The operational amplifier 21 amplifies the voltage signal input at the non-inverting input terminal and outputs it to the BMS module circuit 3 to power it; the gain module determines the amplification factor of the operational amplifier 21 on the input voltage signal. In this process, since the high-impedance input terminal (non-inverting input terminal) only receives a voltage signal with a very small current, the energy consumption of the BMS module circuit 3 at this time mainly comes from the external power supply 4 rather than the battery pack 1; thus effectively reducing the energy consumption of the battery pack 1. The second diode D2 has its anode connected to the anode of the battery pack 1 and its cathode connected to the output terminal. When the voltage of the external power supply 4 is lower than the voltage of the battery pack 1, the battery pack 1 directly supplies power to the BMS module circuit 3 through the second diode D2. At this time, the voltage input to the BMS module circuit 3 is equal to the voltage of the battery pack 1 minus the voltage drop of the second diode D2. The switching between the two power supply modes is achieved by turning on and off the first diode D1 and the second diode D2 when the relative magnitudes of the voltage of the external power supply 4 and the voltage of the battery pack 1 change.

[0053] Preferably, to ensure the protection against surge impacts from the load, appropriate bandwidth, slew rate, and output voltage characteristics (Voh) of the operational amplifier 21 need to be selected. When there is a high voltage surge impact in the load, due to the narrow pulse width of the surge impact, the bandwidth of the operational amplifier 21 limits the surge impact from entering through the operational amplifier 21 and thus affecting the power supply of the BMS module circuit 3. Therefore, in this embodiment, the positive phase proportional operational amplifier circuit 2 is built by using the operational amplifier 21, realizing the isolation between the input power supply of the BMS module circuit 3 and the external power supply 4, thereby avoiding the impact of surge impacts on the BMS module circuit 3. Specifically, the operational amplifier model used in the simulation is OP113, with a maximum output voltage of 14V, a slew rate of 120dB, and a bandwidth of 3.4MHz.

[0054] In addition to the power supply switching function described above, the first diode D1 and the second diode D2 also provide reverse connection protection in their respective circuits. Preferably, the positive-inverting operational amplifier circuit 2 further includes a third diode D3, with the anode of the third diode D3 connected to the positive terminal of the battery pack 1 and the cathode of the third diode D3 connected to the positive input terminal. The third diode D3 provides reverse connection protection. Thus, the three diodes work together to provide reverse connection protection for the BMS input circuit.

[0055] In the technical solution provided in this embodiment, the battery pack is connected to the high-impedance input terminal (non-inverting input terminal) of the operational amplifier to form a non-inverting proportional operational amplifier circuit. By combining the conduction and cutoff of the first diode and the second diode, the power supply can be switched, thereby ensuring that when the voltage of the external power supply is greater than the voltage of the battery pack, the energy consumption of the BMS module circuit mainly comes from the external power supply rather than the battery pack, thus effectively reducing the energy consumption of the battery pack and ensuring the normal operation of the BMS module circuit.

[0056] Preferably, the amplification gain module 22 includes an input resistor R1 and a feedback resistor R. f The input resistor R1 and the feedback resistor R f After being connected in series, it is connected in parallel between the output terminal and the ground terminal of the operational amplifier 21; the feedback resistor Rf is connected to the output terminal, and the input resistor R1 is connected to the ground terminal; the negative input terminal of the operational amplifier 21 is connected to the input resistor R1 and the feedback resistor Rf. f Between. The battery pack 1 outputs a battery voltage signal to the non-inverting input terminal. The operational amplifier 21 amplifies the battery voltage signal received at the non-inverting input terminal to form a battery voltage amplified signal. The voltage value of the battery voltage amplified signal is:

[0057] V==V B+ *(1+R f / R1);

[0058] Among them, R f R1 is the resistance value of the feedback resistor; V is the resistance value of the input resistor; B+ This represents the voltage value of the voltage signal input to the non-inverting input terminal. In this circuit, the second diode D3 provides almost no voltage drop, B + With Battery + The voltages are approximately equal.

[0059] The working process of the BMS input circuit system of this utility model will be described below with reference to specific embodiments and experimental results:

[0060] exist Figure 1Based on the circuit diagram, participate Figure 2 and Figure 3 When voltage T30 is higher than voltage signal Battery + When T30 is higher than Battery, the first diode D1 is turned on, the third diode D3 is turned on, and the second diode D2 is turned off. Specifically, when T30 is higher than Battery... + *(1+R f When / R1), T30 supplies power to operational amplifier 21 (U1) through the first diode D1. At this time, Battery + The signal is fed into the non-inverting input of operational amplifier 21 (U1) through the third diode D3. Operational amplifier 21 (U1) operates according to the feedback resistor R. f The amplification ratio provided by the input resistor R1 will affect the battery. + The signal is amplified to generate a battery voltage amplification signal T30_PROT, with a voltage value V = V. B+ *(1+R f / R1), supplying voltage to BMS module circuit 3. During this process, the power supply for BMS module circuit 3 mainly comes from T30, i.e., external power supply 4, rather than battery pack 1. Voltage changes are as follows: Figure 2 As shown, Figure 2 The following are displayed: T30, T30_PROT, and Battery. + The waveform diagram shows the change over time. As can be seen from the diagram, the T30_PROT signal is unaffected by the external T30 surge, maintaining a stable waveform and ensuring normal power supply to the BMS module circuit 3. When T30 is in Battery... + *(1+R f / R1) and Battery + During this period, operational amplifier 21 (U1) attempts to amplify the battery. + The voltage is limited, but because the T30_PROT signal is clamped to the T30 voltage level, the amplified voltage cannot exceed the T30 voltage. At this time, the BMS module circuit 3 is still powered by T30. Figure 3 The waveform diagram shows that in this case, the T30_PROT signal is clamped at the T30 voltage level, and the waveform is amplified by operational amplifier 21 according to the amplification ratio, which also ensures the stability of the power supply input voltage of BMS module circuit 3. Therefore, when the voltage T30 is higher than the voltage signal Battery... + In this case, BMS module circuit 3 is powered by T30, and the battery will not power BMS module circuit 3, thereby reducing battery power consumption.

[0061] exist Figure 1 Based on the circuit diagram, participate Figure 4 When Battery +When the voltage is higher than T30, the first diode D1 is cut off, while the second diode D2 and the third diode D3 are turned on. + The BMS module circuit 3 is directly powered by the second diode D2. This ensures that even when the external T30 voltage is insufficient, the BMS module circuit 3 can still obtain a stable voltage from the battery pack 1 to maintain basic functions. At this time, the voltage of the T30_PROT signal is Battery 1. + Subtract the voltage drop of the second diode D2. Figure 4 The waveform diagram shows the voltage ratio of the T30_PROT signal to the Battery. + The difference is low, and it is the voltage drop of the second diode D2. Therefore, the BMS input circuit provided in this embodiment can operate when the battery... + When the voltage is higher than T30, ensure that the BMS module circuit 3 continues to be powered by the battery pack 1 to avoid insufficient power supply voltage.

[0062] See Figure 1 and Figure 5 Due to various complex situations occurring in the load, the line inductance in the load causes a short circuit between the external power supply 4 and the battery pack 1, generating a surge voltage. Figure 1 The diagram illustrates a surge voltage generation scenario by connecting a switch K1 to the BMS input circuit. One end of switch K1 is connected to the DC / DC module and the load, and the other end is connected to the positive terminal of the battery pack 1. When the switch is closed, a surge voltage is generated. At this time, there is a high voltage from an external surge impact in T30. Although the first diode D1 is conducting, the bandwidth limitation and output voltage characteristics of the operational amplifier 21 (U1) determine that the external instantaneous surge will not be conducted into the operational amplifier 21 (U1) system. The surge voltage of T30 is filtered out due to the low bandwidth of the operational amplifier 21, and thus cannot be conducted to the power supply terminal of the BMS module circuit 3, thereby enhancing the robustness of the BMS module circuit 3. Figure 5 The waveform diagram shows that T30_PROT remains at a stable voltage, confirming that external shocks have no effect on BMS module circuit 3.

[0063] This invention discloses a BMS input circuit that isolates the input power supply of the BMS module from the external power supply by using an operational amplifier to build a non-inverting operational amplifier circuit, thereby avoiding the impact of surge damage on the BMS module circuit. Simultaneously, this design uses the external power supply as the power supply for the operational amplifier, while the battery pack is connected to the high-impedance input terminal (non-inverting input terminal) of the operational amplifier. Combined with a first diode and a second diode, the power supply switching is achieved, ensuring that when the voltage of the external power supply is greater than the battery pack voltage, the energy consumption of the BMS module circuit mainly comes from the external power supply and not the battery pack, thus effectively reducing the energy consumption of the battery pack.

[0064] In another embodiment, a vehicle is also provided, including a battery management module, the battery management module including the BMS input circuitry described in any of the foregoing aspects.

[0065] It should be noted that the embodiments of this utility model have better implementability and are not intended to limit this utility model in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of this utility model without departing from the content of the technical solution of this utility model shall still fall within the scope of the technical solution of this utility model.

Claims

1. A BMS input circuit system, comprising: BMS circuit, the BMS circuit includes BMS module circuit, and external power supply and battery pack connected to the BMS module circuit; The feature is that it further includes: a positive phase proportional operational amplifier circuit, connected between the external power supply and the power input terminal of the battery pack and the BMS module circuit; the positive phase proportional operational amplifier circuit includes: Operational amplifier, first diode, amplification gain module, and second diode; The positive power supply terminal of the operational amplifier is connected to the negative terminal of the first diode, and the positive terminal of the first diode is connected to the external power supply; the negative power supply terminal is grounded; the positive input terminal is connected to the positive terminal of the battery pack; the negative input terminal is connected to the amplification gain module; the amplification gain module is connected in parallel between the ground terminal and the output terminal; the output terminal is connected to the power supply input terminal of the BMS module circuit, and the BMS module circuit is connected to the negative terminal of the battery pack and grounded. The positive terminal of the second diode is connected to the positive terminal of the battery pack, and the negative terminal is connected to the output terminal.

2. The BMS input circuit system as described in claim 1, characterized in that, It also includes a third diode, the anode of which is connected to the positive terminal of the battery pack, and the cathode of which is connected to the positive input terminal.

3. The BMS input circuit system as described in claim 1, characterized in that, The amplification gain module includes an input resistor and a feedback resistor; The input resistor and the feedback resistor are connected in series and then connected in parallel between the output terminal and the ground terminal; the feedback resistor is connected to the output terminal and the input resistor is connected to the ground terminal; the negative phase input terminal is connected between the input resistor and the feedback resistor.

4. The BMS input circuit system as described in claim 3, characterized in that, The battery pack outputs a battery voltage signal to the non-inverting input terminal. The operational amplifier amplifies the battery voltage signal received at the non-inverting input terminal to form a battery voltage amplified signal. The voltage value of the battery voltage amplified signal is: V=V B+ *(1+R f / R1); Among them, R f R1 is the resistance value of the feedback resistor; V is the resistance value of the input resistor; B+ This is the voltage value of the voltage signal input to the non-inverting input terminal.

5. The BMS input circuit system as described in claim 1, characterized in that, The external power supply is a DC / DC module or a load.

6. The BMS input circuit system as described in claim 5, characterized in that, The load includes a motor.

7. The BMS input circuit system as described in claim 5, characterized in that, The voltage value of the DC / DC module is 12V.

8. An automobile comprising the BMS input circuit system as described in any one of claims 1-7.

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