BMS protection circuit and battery protection board

Abstract

The utility model provides a BMS protection circuit and a battery protection board, the BMS protection circuit is connected between a battery pack positive electrode and a battery pack negative electrode of the BMS circuit, and the BMS protection circuit comprises a first starting circuit, a second starting circuit and an execution circuit; the first starting circuit is connected with an I / O pin of an MCU in the BMS circuit and receives a level signal sent by the I / O pin of the MCU. The second starting circuit is connected with the first starting circuit and receives a level signal sent by the first starting circuit; the execution circuit is connected with the second starting circuit and receives a level signal sent by the second starting circuit. When an external person performs illegal upgrading operation, the I / O pin of the MCU is configured to be in a high level, the first starting circuit and the second starting circuit start the three-end fuse of the execution circuit to be fused internally, and the main current loop of the BMS is disconnected, so that unknown risks such as fire and explosion caused by loss of a protection function after illegal upgrading are avoided.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of energy storage batteries, in particular to a BMS protection circuit and a battery protection board. BACKGROUND

[0002] In the current increasingly competitive battery protection board (BMS) industry, each company has an independent design scheme in realizing a product. Due to the need in the development process, the BOOTLOADER (online upgrade software) mode is derived, but the BOOTLOADER mode also has the risk of being cracked. When the internal upgrade protocol of the company is cracked, the product can also be randomly tampered with by the outside through this mode, thereby causing the risk of failure of the protection function.

[0003] In the prior art, there is a software program-based solution to this problem, but the software resources occupied are more, and the solution implementation process is also relatively complex. There is no hardware circuit-based solution to this problem in the prior art. SUMMARY

[0004] To solve the above technical problems, the utility model provides a kind of BMS protection circuit and battery protection board, the protection circuit is provided with first starting circuit, second starting circuit and execution circuit, first starting circuit directly receives the level signal sent by the I / O pin of MCU in BMS circuit;Second starting circuit receives the level signal sent by first starting circuit;Execution circuit receives the level signal sent by second starting circuit;In the cooperative of three circuits, the BMS protection circuit proposed in the utility model can avoid the risk of fire explosion caused by the loss of protection function after illegal upgrade.

[0005] In the first aspect, the utility model provides a kind of BMS protection circuit, specifically including:

[0006] First starting circuit, second starting circuit and execution circuit.

[0007] Among them, the first starting circuit connects the I / O pin of MCU in BMS circuit, receives the level signal sent by the I / O pin of MCU.

[0008] Second starting circuit connects first starting circuit and receives the level signal sent by first starting circuit.

[0009] Execution circuit connects second starting circuit and receives the level signal sent by second starting circuit.

[0010] Further, the first starting circuit includes: first voltage dividing resistor, second voltage dividing resistor and first field effect transistor.

[0011] Further, the first starting circuit comprises:

[0012] The drain of the first field effect transistor is connected to the second starting circuit, the source of the first field effect transistor is connected to the negative electrode of the battery pack of the BMS circuit, the gate of the first field effect transistor is connected to one end of the first voltage dividing resistor, the other end of the first voltage dividing resistor is connected to the I / O pin of the MCU in the BMS circuit, and the second voltage dividing resistor is connected between the source of the first field effect transistor and the gate of the first field effect transistor.

[0013] When the MCU controls the I / O port to output a high level, the first voltage dividing resistor and the second voltage dividing resistor perform voltage division, the first field effect transistor is turned on, and the first starting circuit is started.

[0014] Further, the second starting circuit comprises: a third voltage dividing resistor, a fourth voltage dividing resistor and a second field effect transistor.

[0015] Further, the second starting circuit comprises:

[0016] The source of the second field effect transistor is connected to the positive electrode of the battery pack of the BMS circuit, the drain of the second field effect transistor is connected to the execution circuit, and the gate of the second field effect transistor is connected to one end of the fourth voltage dividing resistor. The other end of the fourth voltage dividing resistor is connected to the first starting circuit, and the third voltage dividing resistor is connected between the source of the second field effect transistor and the gate of the second field effect transistor.

[0017] When the first starting circuit is started, the third voltage dividing resistor and the fourth voltage dividing resistor perform voltage division, the second field effect transistor is turned on, and the second starting circuit is started.

[0018] Further, the execution circuit comprises: a three-terminal fuse.

[0019] Further, the execution circuit comprises: the first pin of the three-terminal fuse is connected to the negative electrode of the battery pack of the BMS circuit, the second pin of the three-terminal fuse is connected to the second starting circuit, and the third pin of the three-terminal fuse is connected to the negative electrode of the load interface of the BMS circuit.

[0020] When the second starting circuit is started, the negative electrode of the battery pack of the BMS circuit is connected to the second pin of the three-terminal fuse, the internal fuse of the three-terminal fuse is blown, and the main current loop of the BMS circuit is disconnected.

[0021] Further, the first field effect transistor is an N-type field effect transistor.

[0022] Further, the second field effect transistor is a P-type field effect transistor.

[0023] When external people try to tamper with the product software by cracking, the running program in the internal BOOTLOADER program can trigger the protection of the three-terminal safety fuse in the execution circuit, so that the uncontrollable risk of the product after software upgrade is avoided.

[0024] The BMS protection circuit provided by the utility model has the necessary resources of one three-terminal self-control safety fuse, one power P-type field effect transistor, one signal N-type field effect transistor and four field effect transistor driving voltage dividing resistors in the hardware aspect, and the necessary resources of one I / O port with push-pull output capability in the software aspect.

[0025] In the second aspect, the utility model provides a battery protection board, which comprises: a BMS protection circuit integrated on a circuit substrate.

[0026] In summary, the BMS protection circuit and the battery protection board provided by the utility model can realize that when external people perform illegal upgrade operation, the BMS system will run the internal protection program, the I / O pin of the MCU is configured as a high level, the first starting circuit is started, then the second starting circuit is started, and finally the three-terminal safety fuse of the execution circuit is internally fused, so that the main current loop of the BMS is disconnected, and the unknown risks such as fire and explosion caused by the loss of protection function after illegal upgrade are avoided.

[0027] Compared with the prior art, the utility model has at least the following beneficial effects:

[0028] The BMS protection circuit provided by the utility model can simply, efficiently and safely realize the function of preventing illegal BOOTLOADER upgrade operation, avoid unpredictable consequences caused by illegal upgrade of the battery pack, and greatly reduce the labor and production cost, so that the BMS protection circuit is conducive to large-scale production investment. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The BMS circuit diagram shown in the embodiment of the utility model.

[0030] Figure 2 The BMS protection circuit shown in the embodiment of the utility model. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model. Embodiment one

[0032] Referring to Figure 1 It is the BMS circuit diagram schematic diagram shown in the embodiments of the utility model, including BMS basic circuit and BMS protection circuit, the BMS protection circuit is connected between the battery pack positive pole and the battery pack negative pole of BMS circuit.

[0033] Referring to Figure 2 It is the BMS protection circuit schematic diagram shown in the embodiments of the utility model, specifically including:

[0034] The first starting circuit, the second starting circuit and the execution circuit.

[0035] Among them, the first starting circuit connects the I / O pin of MCU in BMS circuit, receives the level signal sent by the I / O pin of MCU.

[0036] The second starting circuit connects the first starting circuit, receives the level signal sent by the first starting circuit.

[0037] The execution circuit connects the second starting circuit, receives the level signal sent by the second starting circuit.

[0038] In the embodiments of the utility model, optionally, the first starting circuit includes: first voltage dividing resistor R3, second voltage dividing resistor R4 and first field effect transistor Q2.

[0039] In the embodiments of the utility model, optionally, the first starting circuit includes: the drain of the first field effect transistor Q2 is connected with the second starting circuit, the source of the first field effect transistor Q2 is connected with the battery pack negative pole of BMS circuit, the gate of the first field effect transistor Q2 is connected with one end of the first voltage dividing resistor R3, the other end of the first voltage dividing resistor R3 is connected with the I / 0 pin of MCU in BMS circuit, the second voltage dividing resistor R4 is connected between the source of the first field effect transistor Q2 and the gate of the first field effect transistor Q2.

[0040] When the MCU controls the I / O port to output high level, the first voltage dividing resistor R3 and the second voltage dividing resistor R4 carry out voltage division, the first field effect transistor Q2 is turned on, and the first starting circuit is started.

[0041] In the embodiment of the utility model, optionally, the second starting circuit includes: third voltage dividing resistor R1, fourth voltage dividing resistor R2 and second field effect transistor Q1.

[0042] In the embodiment of the utility model, optionally, the second starting circuit includes:

[0043] The source of the second field effect transistor is connected with the battery positive pole of the BMS circuit, the drain of the second field effect transistor Q1 is connected with the executing circuit, the gate of the second field effect transistor Q1 is connected with one end of the fourth voltage dividing resistor R2, the other end of the fourth voltage dividing resistor R2 is connected with the first starting circuit, and the third voltage dividing resistor R1 is connected between the source of the second field effect transistor Q1 and the gate of the second field effect transistor Q1.

[0044] When the first starting circuit is started, the third voltage dividing resistor R1 and the fourth voltage dividing resistor R2 divide voltage, the second field effect transistor Q1 is turned on, and the second starting circuit is started.

[0045] In the embodiment of the utility model, optionally, the executing circuit includes: three-terminal fuse F1.

[0046] In the embodiment of the utility model, optionally, the executing circuit includes: the first pin of the three-terminal fuse F1 is connected with the battery negative pole of the BMS circuit, the second pin of the three-terminal fuse F1 is connected with the second starting circuit, and the third pin of the three-terminal fuse F1 is connected with the load interface negative pole of the BMS circuit.

[0047] When the second starting circuit is started, the battery negative pole of the BMS circuit is connected to the second pin of the three-terminal fuse F1, the three-terminal fuse is fused internally, and the main current loop of the BMS circuit is disconnected.

[0048] In the embodiment of the utility model, optionally, the first field effect transistor Q2 is an N-type field effect transistor.

[0049] In the embodiment of the utility model, optionally, the second field effect transistor Q1 is a P-type field effect transistor.

[0050] In the embodiment of the utility model, optional, the specific working principle of circuit is: when the external personnel carries out the non legal artificial upgrade operation, BMS system will run internal BOOTLOADER program, at this time, the I / O pin of the MCU in BMS is configured to high level, the level of the gate of the first field effect transistor Q2 is pulled high, the first voltage divider resistor R3 and the second voltage divider resistor R4 carry out voltage division, thereby causing the first field effect transistor Q2 to be turned on, the first start circuit starts, at this time, the level of the gate of the second field effect transistor Q1 is pulled low, the third voltage divider resistor R1 and the fourth voltage divider resistor R2 carry out voltage division, thereby causing the second field effect transistor Q1 to be turned on, the second start circuit starts, the battery pack negative pole of BMS circuit is connected to the second pin of three-terminal fuse F1, the internal fuse of three-terminal fuse is fused, the main current loop of BMS circuit is disconnected, avoid the risk of fire and explosion caused by the loss of protection function after illegal upgrade.

[0051] In the embodiment of the utility model, optional, the specific meaning of each port letter in the circuit is:

[0052] B+: battery pack positive pole.

[0053] P+ / C+: load interface positive pole, charger input positive pole.

[0054] B- / GND: battery pack negative pole.

[0055] P- / C-: load interface negative pole, charger input negative pole.

[0056] I / O: I / O output pin of MCU in BMS circuit.

[0057] In the embodiment of the utility model, optional, the electronic components used in the circuit meet the following standards:

[0058] Three-terminal fuse F1:

[0059] a. The current capacity of the first pin and the third pin of three-terminal fuse F1 is greater than the output current capacity of BMS.

[0060] b. The working voltage of the first pin and the third pin of three-terminal fuse F1 needs to be greater than the total voltage of the battery cell of BMS system.

[0061] c. The fuse time of the first pin and the third pin of three-terminal fuse F1 needs to meet the design requirements.

[0062] Second field effect transistor Q1:

[0063] a. The ID current of the second field effect transistor Q1 needs to be greater than the current (I=U / R) generated when the three-terminal fuse is fused (R is the internal fuse resistance of SCP).

[0064] b. The VDS voltage resistance of the second field effect transistor Q1 needs to be greater than the total voltage of the battery cell of the BMS system.

[0065] The second field effect transistor Q2:

[0066] a. The ID current of the second field effect transistor Q1 needs to be greater than the current generated by the voltage division of R1 and R2 (I=U / (R1+R2)).

[0067] b. The VDS voltage resistance of the second field effect transistor Q1 needs to be greater than the total voltage of the battery cell of the BMS system.

[0068] The first voltage dividing resistor R3 and the second voltage dividing resistor R4:

[0069] a. The resistance voltage division needs to meet that the voltage on R4 is less than 20V (the general MOS VGS voltage resistance is 20V).

[0070] b. The resistance package selection, the resistance voltage resistance and power of different packages are different.

[0071] The third voltage dividing resistor R1 and the fourth voltage dividing resistor R2:

[0072] a. The resistance voltage division needs to meet that the voltage on R1 is less than 20V (the general MOS VGS voltage resistance is 20V).

[0073] b. The resistance package selection, the resistance voltage resistance and power of different packages are different. Embodiment two:

[0074] The utility model provides a kind of battery protection board, comprising: BMS protection circuit, the BMS protection circuit is integrated on circuit substrate;Battery protection board includes: the BMS protection circuit described above, and circuit substrate, BMS protection circuit is integrated on circuit substrate.

[0075] In the utility model embodiment, the material used by the circuit substrate is glass fiber reinforced epoxy resin, but not limited to this.

[0076] In conclusion, the BMS protection circuit and the battery protection board provided by the utility model can realize that when an external person performs illegal artificial upgrading operation, the BMS system will run the internal protection program, the I / O pin of the MCU is configured as high level, the first starting circuit is started, and then the second starting circuit is started, and finally the three-terminal fuse inside the execution circuit is fused, the main current loop of the BMS is disconnected, and the unknown risks such as fire and explosion caused by the loss of protection function after illegal upgrading are avoided.

[0077] The BMS protection circuit can simply, efficiently and safely realize the function of preventing illegal BOOTLOADER upgrade operation, avoids unpredictable consequences caused by illegal upgrade of the battery pack, and the hardware resources and software resources used by the BMS protection circuit are few, so that the manpower and production cost are greatly reduced, and large-scale production investment is facilitated.

[0078] The above-described specific embodiments further specifically describe the purpose, technical solutions and beneficial effects of the utility model, and it should be understood that the above-described specific embodiments are merely specific embodiments of the utility model and are not used to limit the protection scope of the utility model. It is particularly pointed out that, for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A BMS protection circuit, characterized in that, The BMS protection circuit is connected between the positive electrode and the negative electrode of the battery pack of the BMS circuit, and specifically comprises a first starting circuit, a second starting circuit and an execution circuit. The first starting circuit is connected to an I / O pin of an MCU in the BMS circuit and receives a level signal sent by the I / O pin of the MCU. The second starting circuit is connected to the first starting circuit and receives a level signal sent by the first starting circuit. The execution circuit is connected to the second starting circuit and receives a level signal sent by the second starting circuit.

2. The BMS protection circuit of claim 1, wherein, The first starting circuit comprises a first voltage dividing resistor, a second voltage dividing resistor and a first field effect transistor.

3. The BMS protection circuit of claim 2, wherein, The first starting circuit comprises: The drain of the first field effect transistor is connected to the second starting circuit, the source of the first field effect transistor is connected to the negative electrode of the battery pack of the BMS circuit, the gate of the first field effect transistor is connected to one end of the first voltage dividing resistor, the other end of the first voltage dividing resistor is connected to the I / O pin of the MCU in the BMS circuit, and the second voltage dividing resistor is connected between the source of the first field effect transistor and the gate of the first field effect transistor. When the MCU controls the I / O port to output a high level, the first voltage dividing resistor and the second voltage dividing resistor perform voltage division, the first field effect transistor is turned on, and the first starting circuit is started.

4. The BMS protection circuit of claim 2, wherein, The second starting circuit comprises a third voltage dividing resistor, a fourth voltage dividing resistor and a second field effect transistor.

5. The BMS protection circuit of claim 4, wherein, The second starting circuit comprises: The source of the second field effect transistor is connected to the positive electrode of the battery pack of the BMS circuit, the drain of the second field effect transistor is connected to the execution circuit, the gate of the second field effect transistor is connected to one end of the fourth voltage dividing resistor, the other end of the fourth voltage dividing resistor is connected to the first starting circuit, and the third voltage dividing resistor is connected between the source of the second field effect transistor and the gate of the second field effect transistor; when the first starting circuit is started, the third voltage dividing resistor and the fourth voltage dividing resistor perform voltage division, the second field effect transistor is turned on, and the second starting circuit is started.

6. The BMS protection circuit of claim 2, wherein, The execution circuit comprises a three-terminal fuse.

7. The BMS protection circuit of claim 6, wherein, The execution circuit comprises a three-terminal fuse, the first pin of the three-terminal fuse is connected to the negative electrode of the battery pack of the BMS circuit, the second pin of the three-terminal fuse is connected to the second starting circuit, and the third pin of the three-terminal fuse is connected to the negative electrode of the load interface of the BMS circuit. When the second starting circuit is started, the negative electrode of the battery pack of the BMS circuit is connected to the second pin of the three-terminal fuse, the three-terminal fuse is internally fused, and the main current loop of the BMS circuit is disconnected.

8. The BMS protection circuit of claim 2, wherein, The first field effect transistor is an N-type field effect transistor.

9. The BMS protection circuit of claim 4, wherein, The second field effect transistor is a P-type field effect transistor.

10. A battery protection plate characterized by, The BMS protection circuit comprises: The BMS protection circuit according to any one of claims 1 to 9 is integrated on a circuit substrate. The battery protection board comprises the BMS protection circuit and a circuit substrate, and the BMS protection circuit is integrated on the circuit substrate.

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