BMS positive end control secondary protection function verification circuit and tool
By designing a verification circuit for the secondary protection function of the BMS positive terminal control, and utilizing switching transistors and voltage divider circuits in conjunction with indicator lights, the problem of difficulty in fully inspecting the secondary protection circuit of lithium batteries was solved. This achieved a low-cost and efficient testing method, improving product quality and stability.
Patent Information
- Application Number
- CN202423176810.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-12-20
AI Technical Summary
Existing lithium battery secondary protection circuits are difficult to fully inspect in mass production, and the full inspection method for three-terminal fuses is costly, making it difficult to guarantee product quality and stability.
The secondary protection function verification circuit is controlled by the positive terminal of the BMS. It uses a switching transistor and voltage divider circuit design, combined with indicator lights, to achieve full inspection of the secondary protection circuit. The circuit uses conventional electronic components, which are low cost and reusable.
It enables full inspection of secondary protection circuits, reduces testing costs, improves product quality and stability, and makes the testing process intuitive and convenient.
Smart Images
Figure CN223692482U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to lithium ion battery protection technical field especially, it relates to a BMS positive terminal control secondary protection function verification circuit and tool. BACKGROUND
[0002] Lithium battery is used in many products at present, because its chemical characteristic is very active, needs protection circuit to carry out safety protection, therefore appears the electric core protection cover of lithium battery 'battery protection board', the primary protection circuit of lithium battery will be equipped in battery protection board, it can actively monitor the charge and discharge state of electric core and eliminate the security risk in time.
[0003] But, because part device in protection circuit can have certain ratio short circuit failure, in order to prevent part device failure and lead to protection circuit unable to take effect, therefore needs to add a secondary protection circuit outside main loop, to ensure the safety of lithium battery. At present, the secondary protection circuit that the market is most commonly used is that the protection effect is best, and it is through the collocation of secondary protection IC (integrated circuit) and the three-terminal fuse on the protection board under test to carry out hardware protection, and its circuit schematic diagram is as shown in Figure 1 .
[0004] In actual production, in order to improve product quality, ensure the reliability and stability of product, will require line board full inspection;But, because the existing full inspection method of three-terminal fuse is difficult to implement, and the cost is high, therefore, at present, this secondary protection circuit scheme using three-terminal fuse is difficult to realize full inspection in mass production, or it is easy to burn out fuse and increase process and cost.
[0005] For those skilled in the art, how to ensure the full inspection feasibility of battery protection board under the premise, and give consideration to the cost and convenience of secondary protection circuit, become the technical problem to be solved in the field.
[0006] The above information is given as background information only to assist in understanding the present disclosure, and does not determine or acknowledge whether any of the above content can be used as prior art against the present disclosure. UTILITY MODEL CONTENT
[0007] The utility model aims at providing a kind of BMS positive terminal control secondary protection function verification circuit and tool, to solve or at least partially solve the technical problems in prior art.
[0008] To achieve this purpose, the utility model adopts the following technical solutions:
[0009] Firstly, the utility model provides a kind of BMS positive terminal control secondary protection function verification circuit, including switch tube Q1, switch tube Q2, switch tube Q3 and switch tube Q4;
[0010] The negative terminal of the switch tube Q1 is used for electrically connecting the positive output end of the charging device, the negative terminal of the switch tube Q4 is used for electrically connecting the positive pole of the battery, the positive terminal of the switch tube Q1 is electrically connected with the positive terminal of the switch tube Q4, and the control terminal of the switch tube Q1 is electrically connected with the control terminal of the switch tube Q4;
[0011] The positive terminal of the switch tube Q2 is electrically connected with the control terminal of the switch tube Q1, the negative terminal of the switch tube Q2 is used for electrically connecting the reference ground of the charging device, and the control terminal of the switch tube Q2 is electrically connected with the voltage output end of the voltage dividing circuit, and the voltage input end of the voltage dividing circuit is used for electrically connecting the positive pole of the battery;
[0012] The control terminal of the switch tube Q2 is also electrically connected with the positive terminal of the switch tube Q3, the negative terminal of the switch tube Q3 is used for electrically connecting the reference ground of the charging device, the control terminal of the switch tube Q3 is used for electrically connecting the IC control signal output terminal of the battery protection board to be tested, and the control terminal of the switch tube Q3 is also electrically connected with the positive terminal of the signal lamp LED1, and the negative terminal of the signal lamp LED1 is used for electrically connecting the reference ground of the charging device;
[0013] When the battery protection board works normally, the control terminal of the switch tube Q2 is connected with a high-level signal, the switch tube Q2 is turned on, the control terminals of the switch tube Q1 and the switch tube Q4 are pulled down to low level, the switch tube Q1 and the switch tube Q4 are turned on, and the charging main circuit is turned on.
[0014] When the battery protection board triggers the secondary overcharge, the IC control signal output terminal outputs a high-level signal, the signal lamp LED1 is turned on, the control terminal of the switch tube Q3 is set to high level, the switch tube Q3 is turned on, the control terminal of the switch tube Q2 is pulled down to low level, the switch tube Q2 is turned off or not turned on, and then the switch tube Q1 and the switch tube Q4 are turned off or not turned on, and the charging main circuit is turned off.
[0015] Optionally, the negative terminal of the switch tube Q1 is also electrically connected with the first end of the resistor R3, the second end of the resistor R3 is electrically connected with the positive terminal of the signal lamp LED2, and the negative terminal of the signal lamp LED2 is used for electrically connecting the reference ground of the charging device;
[0016] When the charging main circuit is turned off, the signal lamp LED2 is turned on.
[0017] Optionally, the signal lamp LED1 is a red LED lamp, and the signal lamp LED2 is a green LED lamp,
[0018] Optionally, the control terminal of the switch tube Q1 is also electrically connected with the first end of the resistor R1, and the second end of the resistor R1 is electrically connected with the positive terminal of the switch tube Q2;
[0019] The control end of the switch tube Q2 is further electrically connected with the positive pole of the capacitor C2, the first end of the resistor R7 and the negative pole of the voltage stabilizing tube Z3, and the negative pole of the capacitor C2, the second end of the resistor R7 and the positive pole of the voltage stabilizing tube Z3 are all electrically connected with the negative wiring end of the switch tube Q2;
[0020] The positive wiring end of the switch tube Q3 is further electrically connected with the first end of the resistor R6, and the second end of the resistor R6 is electrically connected with the control end of the switch tube Q2.
[0021] Optionally, the control end of the switch tube Q3 is further electrically connected with the first end of the resistor R8, the first end of the resistor R9, the positive pole of the capacitor C1 and the negative pole of the voltage stabilizing tube Z2, the second end of the resistor R8 is electrically connected with the first end of the resistor R11, the second end of the resistor R11 is electrically connected with the positive wiring end of the signal lamp LED1, the second end of the resistor R9, the negative pole of the capacitor C1 and the positive pole of the voltage stabilizing tube Z2 are all electrically connected with the negative wiring end of the LED1.
[0022] Optionally, the voltage dividing circuit comprises a resistor R10, a resistor R4 and a resistor R5;
[0023] The first end of the resistor R10 is further electrically connected with the negative pole of the diode D1, the positive pole of the diode D1 is the voltage input end of the voltage dividing circuit, the second end of the resistor R10 is respectively electrically connected with the first end of the resistor R4 and the first end of the resistor R5, the second end of the resistor R4 is used for electrically connecting the reference ground of the charging device, and the second end of the resistor R5 is the voltage output end of the voltage dividing circuit.
[0024] Optionally, the negative wiring end of the switch tube Q4 is further electrically connected with the first end of the resistor R2 and the negative pole of the voltage stabilizing tube Z1, and the second end of the resistor R2 and the positive pole of the voltage stabilizing tube Z1 are all electrically connected with the control end of the switch tube Q1.
[0025] Optionally, the switch tube Q1 and the switch tube Q4 are PMOS tubes or PNP tubes, and the switch tube Q2 and the switch tube Q3 are NMOS tubes or NPN tubes.
[0026] Optionally, the switch tube Q1 and the switch tube Q4 are both enhancement-mode PMOS tubes, and the switch tube Q2 and the switch tube Q3 are both enhancement-mode NMOS tubes.
[0027] The gate of the switch tube Q1 is the control end of the switch tube Q1, the source of the switch tube Q1 is the positive wiring end of the switch tube Q1, and the drain of the switch tube Q1 is the negative wiring end of the switch tube Q1; the gate of the switch tube Q4 is the control end of the switch tube Q4, the source of the switch tube Q4 is the positive wiring end of the switch tube Q4, and the drain of the switch tube Q4 is the negative wiring end of the switch tube Q4.
[0028] The gate of the switch tube Q2 is a control end of the switch tube Q2, the source of the switch tube Q2 is a negative connection end of the switch tube Q2, and the drain of the switch tube Q2 is a positive connection end of the switch tube Q2.
[0029] In a second aspect, the utility model provides a test and verification fixture, which is provided with a function verification circuit, characterized in that the function verification circuit adopts the BMS positive end control secondary protection function verification circuit.
[0030] Compared with the prior art, the utility model has the following beneficial effects:
[0031] The test and verification fixture provided by the utility model is provided with a BMS positive end control secondary protection function verification circuit, can complete full detection of a battery protection board adopting a three-terminal fuse secondary protection circuit scheme, all the electronic components used in the circuit are conventional, the cost is low, and when inspection, the fixture can be connected with each port of the battery protection board to be detected to carry out full detection verification, and the test and verification fixture can be reused, which is very convenient.
[0032] The utility model has other characteristics and advantages, which will be obvious from the drawings and subsequent specific embodiments incorporated herein or will be described in detail in the drawings and subsequent specific embodiments incorporated herein, which are used together to explain the specific principles of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0033] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating creative labor.
[0034] Figure 1 It is a principle diagram of a secondary protection circuit of a lithium battery in the prior art.
[0035] Figure 2 It is a structure principle diagram of a BMS positive end control secondary protection function verification circuit provided by the utility model embodiment. DETAILED DESCRIPTION
[0036] To explain possible application scenarios, technical principles, specific implementation schemes, and the purposes and effects of the present application in detail, the following embodiments are described in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.
[0037] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.
[0038] Unless otherwise defined, the meaning of the technical terms used herein is the same as that generally understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.
[0039] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this paper generally represents that the associated objects before and after are a "or" logical relationship.
[0040] In the present application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.
[0041] In the present application, without more limitation, the "includes", "contains", "has" or other similar expressions used in the sentence are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.
[0042] As the same understanding in the "Examination Guidelines", in the present application, "greater than", "less than", "exceed" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise explicitly specified.
[0043] In the description of the embodiments of the present application, the spatially related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, the indicated orientation or position relationship is based on the orientation or position relationship shown in the specific embodiment or the drawing, only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and is not indicative or implied that the indicated device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, therefore cannot be understood as a limitation on the embodiments of the present application.
[0044] Unless otherwise explicitly specified or limited, in the description of the embodiments of the present application, the terms "mounting", "connecting", "connecting", "fixing", "setting" and the like should be understood broadly. For example, the "connection" can be fixed connection, or detachable connection, or integrated setting; it can be mechanical connection, or electrical connection, or communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0045] Embodiment one:
[0046] Please refer to Figure 2 , Figure 2 is a structure principle diagram of a BMS positive terminal control secondary protection function verification circuit provided by the embodiment of the present application;
[0047] As Figure 2 shown, a BMS (Battery Management System, battery management system) positive terminal control secondary protection function verification circuit, comprising a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; wherein the switch tube Q1 and the switch tube Q4 can be selected from PMOS tube or PNP tube, the switch tube Q2 and the switch tube Q3 can be selected from NMOS tube or NPN tube;
[0048] For example, in this embodiment, both switch Q1 and switch Q4 are enhancement-mode PMOS transistors, and both switch Q2 and switch Q3 are enhancement-mode NMOS transistors.
[0049] Specifically, the negative terminal of the switching transistor Q1 is used to electrically connect to the positive output terminal of the charging device. Figure 2 The P+ terminal (in the circuit) and the negative terminal of the switching transistor Q4 are used to electrically connect to the positive terminal of the battery. Figure 2 (B+ connection terminal in the middle), the positive terminal of switch Q1 is electrically connected to the positive terminal of switch Q4, and the control terminal of switch Q1 is electrically connected to the control terminal of switch Q4.
[0050] The positive terminal of switch Q2 is electrically connected to the control terminal of switch Q1, and the negative terminal of switch Q2 is used to electrically connect to the reference ground of the charging device. Figure 2 The P-connection terminal of the switching transistor Q2 is electrically connected to the voltage output terminal of the voltage divider circuit. Figure 2 The EN_2 connection terminal in the voltage divider circuit is used to electrically connect to the positive terminal of the battery.
[0051] The control terminal of switch Q2 is also electrically connected to the positive terminal of switch Q3. The negative terminal of switch Q3 is used to electrically connect to the reference ground of the charging device. The control terminal of switch Q3 is used to electrically connect to the IC control signal output terminal of the battery protection board under test. Figure 2 (EN_1 connection terminal); The control terminal of the switching transistor Q3 is also electrically connected to the positive terminal of the indicator LED1, and the negative terminal of the indicator LED1 is used to electrically connect to the reference ground of the charging equipment;
[0052] For example, in this embodiment, before performing a full inspection and verification of the battery protection board, it is necessary to correctly connect the aforementioned BMS positive terminal control secondary protection function verification circuit to the battery protection board under test, that is, to connect the positive and negative terminals of the battery on the battery protection board (i.e., the positive and negative terminals of the battery). Figure 2 The B+ and B- terminals of the circuit board under test are connected in parallel to the nebula testing equipment, and the positive and negative output terminals of the charging equipment (or charger) are connected in parallel to the corresponding terminals of the circuit board under test. Figure 2 The P+ and P- terminals are directly connected to the Nebula device, and the IC control signal output terminal of the secondary protection circuit chip on the battery protection board is connected to the corresponding terminal on this board. It is understood that using the Nebula testing equipment is a standard testing method in this field, therefore, its implementation details will not be elaborated in this embodiment. The specific testing process is as follows:
[0053] When the battery protection board is working normally, a high-level signal is applied to the control terminal of switch Q2, turning on switch Q2. This pulls the control terminals of switches Q1 and Q4 low, turning on switches Q1 and Q4, and activating the main charging circuit (i.e., Figure 2The thick line between the middle B+ and P+ is the line where the switch is on;
[0054] When the battery protection board triggers the secondary overcharge, the IC control signal output terminal outputs a high level signal, the signal lamp LED1 is lit, the control end of the switch tube Q3 is set to high level, the switch tube Q3 is turned on, the control end of the switch tube Q2 is pulled to low level, the switch tube Q2 is turned off or not turned on, and then the switch tube Q1 and the switch tube Q4 are turned off or not turned on, and the charging main circuit is turned off.
[0055] Specifically, in the embodiment, the gate of the switch tube Q1 is the control end of the switch tube Q1, the source of the switch tube Q1 is the positive connection end of the switch tube Q1, and the drain of the switch tube Q1 is the negative connection end of the switch tube Q1; the gate of the switch tube Q4 is the control end of the switch tube Q4, the source of the switch tube Q4 is the positive connection end of the switch tube Q4, and the drain of the switch tube Q4 is the negative connection end of the switch tube Q4;
[0056] The gate of the switch tube Q2 is the control end of the switch tube Q2, the source of the switch tube Q2 is the negative connection end of the switch tube Q2, and the drain of the switch tube Q2 is the positive connection end of the switch tube Q2; the gate of the switch tube Q3 is the control end of the switch tube Q3, the source of the switch tube Q3 is the negative connection end of the switch tube Q3, and the drain of the switch tube Q3 is the positive connection end of the switch tube Q3.
[0057] The above-mentioned BMS positive terminal control secondary protection function verification circuit can complete the full detection of the battery protection board adopting the secondary protection circuit scheme of the three-terminal fuse, and all the electronic components used in the circuit are conventional, low in cost, and the verification circuit can be reused, which is very convenient.
[0058] Specifically, the negative connection end of the switch tube Q1 is also electrically connected with the first end of the resistor R3, the second end of the resistor R3 is electrically connected with the positive connection end of the signal lamp LED2, and the negative connection end of the signal lamp LED2 is used to electrically connect the reference ground of the charging device;
[0059] When the charging main circuit is turned off, the signal lamp LED2 is lit.
[0060] Further, the signal lamp LED1 is a red LED lamp, and the signal lamp LED2 is a green LED lamp.
[0061] In the test verification process, when the green light is lit, it represents that the secondary overcharge protection is triggered, and the charging main circuit is turned off, that is, at this time, the IC control signal output terminal of the battery protection board should output a high level signal, otherwise the test is failed.
[0062] And once the secondary overcharge protection trigger, if the battery protection board IC control signal output terminal normal output high level signal, the red light will also immediately lit, indicating that the battery protection board of secondary overcharge protection function can be triggered normally, the detection process is very intuitive and convenient.
[0063] Specifically, the control end of the switch tube Q1 is further electrically connected with the first end of the resistor R1, and the second end of the resistor R1 is electrically connected with the positive connection end of the switch tube Q2.
[0064] The control end of the switch tube Q2 is further electrically connected with the positive electrode of the capacitor C2, the first end of the resistor R7 and the negative electrode of the voltage stabilizing tube Z3, and the negative electrode of the capacitor C2, the second end of the resistor R7 and the positive electrode of the voltage stabilizing tube Z3 are all electrically connected with the negative connection end of the switch tube Q2.
[0065] The positive connection end of the switch tube Q3 is further electrically connected with the first end of the resistor R6, and the second end of the resistor R6 is electrically connected with the control end of the switch tube Q2.
[0066] Specifically, the control end of the switch tube Q3 is further electrically connected with the first end of the resistor R8, the first end of the resistor R9, the positive electrode of the capacitor C1 and the negative electrode of the voltage stabilizing tube Z2, the second end of the resistor R8 is electrically connected with the first end of the resistor R11, the second end of the resistor R11 is electrically connected with the positive connection end of the signal lamp LED1, and the second end of the resistor R9, the negative electrode of the capacitor C1 and the positive electrode of the voltage stabilizing tube Z2 are all electrically connected with the negative connection end of the LED1.
[0067] Specifically, the voltage dividing circuit comprises a resistor R10, a resistor R4 and a resistor R5.
[0068] The first end of the resistor R10 is further electrically connected with the negative electrode of the diode D1, the positive electrode of the diode D1 is the voltage input end of the voltage dividing circuit, the second end of the resistor R10 is respectively electrically connected with the first end of the resistor R4 and the first end of the resistor R5, the second end of the resistor R4 is used for electrically connecting the reference ground P- of the charging device, and the second end of the resistor R5 is the voltage output end of the voltage dividing circuit.
[0069] Specifically, the negative connection end of the switch tube Q4 is further electrically connected with the first end of the resistor R2 and the negative electrode of the voltage stabilizing tube Z1, and the second end of the resistor R2 and the positive electrode of the voltage stabilizing tube Z1 are all electrically connected with the control end of the switch tube Q1.
[0070] It can be understood that in the embodiment, suitable components can be selected according to different application requirements. For example, in the embodiment, the resistance value of the resistor R1 is 2M ohms, the resistance value of the resistor R2 is 1M ohms, the resistance value of the resistor R3 is 220K ohms, the resistance value of the resistor R4 is 2M ohms, the resistance value of the resistor R5 is 2M ohms, the resistance value of the resistor R6 is 1K ohms, the resistance value of the resistor R7 is 100K ohms, the resistance value of the resistor R8 is 3M ohms, the resistance value of the resistor R9 is 2M ohms, and the resistance value of the resistor R10 is 10M ohms. The capacitor C1 and the capacitor C2 are both selected as 0.1 microfarad / 50V capacitors.
[0071] In summary, the embodiment realizes secondary protection testing of the battery protection board to be tested using the star cloud test equipment. The initial state of the circuit is a battery protection board in a simulated normal working state. When the star cloud test equipment is set to a secondary protection state trigger condition, the function of the secondary protection can be simulated and verified. The circuit is simple, and the feasibility and reliability are high. The cost can be effectively reduced. In addition, the circuit has high universality. When the BMS is a positive terminal control, it can be used regardless of the number of strings.
[0072] Embodiment two:
[0073] The embodiment provides a test and verification fixture, which is provided with a function verification circuit. The function verification circuit adopts the BMS positive terminal control secondary protection function verification circuit of the embodiment one.
[0074] Based on the detailed description of the BMS positive terminal control secondary protection function verification circuit in the embodiment one, the embodiment will not be described again.
[0075] Specifically, the battery is a lithium ion battery.
[0076] The test and verification fixture provided by the embodiment can complete full inspection of the battery protection board adopting the secondary protection circuit scheme of the three-terminal fuse. In addition, all the electronic components used in the circuit are conventional and low in cost. When inspection is performed, the fixture only needs to be connected to each port of the battery protection board to be tested to carry out full inspection and verification. In addition, the test and verification fixture can be reused, which is very convenient and saves detection cost.
[0077] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features. The modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A BMS positive terminal control secondary protection function verification circuit, characterized in that, The switch tube Q1, the switch tube Q2, the switch tube Q3 and the switch tube Q4 are included. The negative connection end of the switch tube Q1 is used for electrically connecting the positive output end of the charging device, the negative connection end of the switch tube Q4 is used for electrically connecting the positive pole of the battery, the positive connection end of the switch tube Q1 is electrically connected with the positive connection end of the switch tube Q4, and the control end of the switch tube Q1 is electrically connected with the control end of the switch tube Q4. The positive connection end of the switch tube Q2 is electrically connected with the control end of the switch tube Q1, the negative connection end of the switch tube Q2 is used for electrically connecting the reference ground of the charging device, and the control end of the switch tube Q2 is electrically connected with the voltage output end of the voltage dividing circuit, and the voltage input end of the voltage dividing circuit is used for electrically connecting the positive pole of the battery. The control end of the switch tube Q2 is also electrically connected with the positive connection end of the switch tube Q3, the negative connection end of the switch tube Q3 is used for electrically connecting the reference ground of the charging device, the control end of the switch tube Q3 is used for electrically connecting the IC control signal output terminal of the battery protection plate to be tested, and the control end of the switch tube Q3 is also electrically connected with the positive connection end of the signal lamp LED1, and the negative connection end of the signal lamp LED1 is used for electrically connecting the reference ground of the charging device. When the battery protection plate works normally, the control end of the switch tube Q2 is connected with a high-level signal, the switch tube Q2 is turned on, the control ends of the switch tube Q1 and the switch tube Q4 are pulled low to be low-level, the switch tube Q1 and the switch tube Q4 are turned on, and the charging main circuit is turned on. When the battery protection plate triggers the secondary overcharge, the IC control signal output terminal outputs a high-level signal, the signal lamp LED1 is lighted, the control end of the switch tube Q3 is set to be high-level, the switch tube Q3 is turned on, the control end of the switch tube Q2 is pulled low to be low-level, the switch tube Q2 is turned off or not turned on, and then the switch tube Q1 and the switch tube Q4 are turned off or not turned on, and the charging main circuit is turned off.
2. The BMS positive terminal control secondary protection function verification circuit according to claim 1, characterized in that, The negative connection end of the switch tube Q1 is also electrically connected with the first end of the resistor R3, the second end of the resistor R3 is electrically connected with the positive connection end of the signal lamp LED2, and the negative connection end of the signal lamp LED2 is used for electrically connecting the reference ground of the charging device. When the charging main circuit is turned off, the signal lamp LED2 is lighted.
3. The BMS positive terminal control secondary protection function verification circuit according to claim 2, characterized in that, The signal lamp LED1 is a red LED lamp, and the signal lamp LED2 is a green LED lamp.
4. The BMS positive terminal control secondary protection function verification circuit according to claim 1, characterized in that, The control end of the switch tube Q1 is also electrically connected with the first end of the resistor R1, and the second end of the resistor R1 is electrically connected with the positive connection end of the switch tube Q2. The control end of the switch tube Q2 is also electrically connected with the positive pole of the capacitor C2, the first end of the resistor R7 and the negative pole of the voltage stabilizing tube Z3, respectively, and the negative pole of the capacitor C2, the second end of the resistor R7 and the positive pole of the voltage stabilizing tube Z3 are all electrically connected with the negative connection end of the switch tube Q2. The positive connection end of the switch tube Q3 is also electrically connected with the first end of the resistor R6, and the second end of the resistor R6 is electrically connected with the control end of the switch tube Q2.
5. The BMS positive terminal control secondary protection function verification circuit according to claim 4, characterized in that, The control end of the switch tube Q3 is also electrically connected with the first end of the resistor R8, the first end of the resistor R9, the positive pole of the capacitor C1 and the negative pole of the voltage stabilizing tube Z2, respectively, the second end of the resistor R8 is electrically connected with the first end of the resistor R11, the second end of the resistor R11 is electrically connected with the positive connection end of the signal lamp LED1, the second end of the resistor R9, the negative pole of the capacitor C1 and the positive pole of the voltage stabilizing tube Z2 are all electrically connected with the negative connection end of the LED1.
6. The BMS positive terminal control secondary protection function verification circuit according to claim 1, characterized in that, The voltage dividing circuit comprises a resistor R10, a resistor R4 and a resistor R5. A first end of the resistor R10 is also electrically connected to a negative electrode of a diode D1, a positive electrode of the diode D1 is a voltage input end of the voltage dividing circuit, a second end of the resistor R10 is electrically connected to a first end of the resistor R4 and a first end of the resistor R5 respectively, a second end of the resistor R4 is used for electrically connecting a reference ground of the charging device, and a second end of the resistor R5 is a voltage output end of the voltage dividing circuit.
7. The BMS positive terminal control secondary protection function verification circuit according to claim 1, characterized in that, A first end of the resistor R2 and a negative electrode of the voltage stabilizing tube Z1 are also electrically connected to a negative connection end of the switch tube Q4, and a second end of the resistor R2 and a positive electrode of the voltage stabilizing tube Z1 are electrically connected to the control end of the switch tube Q1.
8. The BMS positive terminal control secondary protection function verification circuit according to claim 1, characterized in that, The switch tube Q1 and the switch tube Q4 are PMOS tubes or PNP tubes, and the switch tube Q2 and the switch tube Q3 are NMOS tubes or NPN tubes.
9. The BMS positive terminal control secondary protection function verification circuit according to claim 8, characterized in that, The switch tube Q1 and the switch tube Q4 are both enhancement-mode PMOS tubes, and the switch tube Q2 and the switch tube Q3 are both enhancement-mode NMOS tubes. The gate of the switch tube Q1 is the control end of the switch tube Q1, the source of the switch tube Q1 is the positive connection end of the switch tube Q1, and the drain of the switch tube Q1 is the negative connection end of the switch tube Q1; the gate of the switch tube Q4 is the control end of the switch tube Q4, the source of the switch tube Q4 is the positive connection end of the switch tube Q4, and the drain of the switch tube Q4 is the negative connection end of the switch tube Q4. The gate of the switch tube Q2 is the control end of the switch tube Q2, the source of the switch tube Q2 is the negative connection end of the switch tube Q2, and the drain of the switch tube Q2 is the positive connection end of the switch tube Q2; the gate of the switch tube Q3 is the control end of the switch tube Q3, the source of the switch tube Q3 is the negative connection end of the switch tube Q3, and the drain of the switch tube Q3 is the positive connection end of the switch tube Q3.
10. A test and verification fixture, wherein a functional verification circuit is provided, characterized in that, The function verification circuit adopts the BMS positive end control secondary protection function verification circuit according to any one of claims 1-9.