Lithium battery intrinsic safety output circuit

Abstract

The utility model discloses a lithium battery intrinsic safety output circuit, which comprises a charging anti-reverse circuit, an overcurrent and overheat protection circuit, an output current-limiting protection circuit and a plurality of battery packs connected in series, and each battery pack comprises two batteries connected in parallel. Each battery in each battery pack is connected with a charging anti-reverse circuit; each battery in each battery pack is connected with an overcurrent and overheat protection circuit, the overcurrent and overheat protection circuit comprises an ideal diode, the batteries are connected with the input end of the ideal diode, the output end of the ideal diode is connected with the input end of an output current-limiting protection circuit, and the output current-limiting protection circuit is connected with the output current-limiting protection circuit. And the two ideal electrodes in the same battery pack are connected in parallel. The intrinsic safety output circuit of the lithium battery protects the service life and the stability of the lithium battery, prevents reverse charging between the batteries, prevents overheating and overcurrent phenomena, reduces the operation and maintenance cost, improves the use value and the safety value, and is more convenient to popularize.

Description

Technical Field

[0001] The utility model relates to an intrinsically safe output circuit for a lithium battery, belonging to the technical field of safety monitoring. Background Art

[0002] At present, the national gas industry is developing rapidly, and liquefied gas, natural gas, coal-to-gas and other gases have been widely used in industry and commerce as clean energy.

[0003] With the widespread use of natural gas, natural gas safety monitoring equipment has also gained widespread adoption. Natural gas safety monitoring equipment can be categorized as either wired or wireless. Wired devices utilize wired power and communication, while wireless devices utilize lithium batteries for power and wireless communication. However, wireless devices face challenges such as uneven lithium battery discharge and flammability and explosiveness, which can cause inconvenience for customers. As wireless devices age, problems such as scattered installation locations, long distances, and excessive wear and tear frequently arise, increasing maintenance and operating costs. Therefore, mitigating the impact of lithium battery uncertainties on equipment is urgent. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a lithium battery intrinsically safe output circuit, which not only protects the life and stability of the lithium battery, prevents reverse charging between batteries, prevents overheating and overcurrent, reduces operation and maintenance costs, improves use value and safety value, and is more convenient for promotion.

[0005] In order to solve the above technical problems, the technical solution of the utility model is:

[0006] A lithium battery intrinsically safe output circuit, comprising a charging reverse protection circuit, an overcurrent and overheat protection circuit, an output current limiting protection circuit, and a plurality of battery packs connected in series, each of which comprises two batteries connected in parallel;

[0007] Each battery in each of the battery packs is connected to a charge reverse protection circuit;

[0008] Each battery in each battery pack is connected to an overcurrent and overheating protection circuit, which includes an ideal diode. The battery is connected to the input end of the ideal diode, and the output end of the ideal diode is connected to the input end of the output current limiting protection circuit. The two ideal diodes in the same battery pack are connected in parallel.

[0009] Furthermore, the charging anti-reverse circuit includes a current limiting resistor and an anti-reverse diode, and the current limiting resistor, the anti-reverse diode and the positive and negative electrodes of the battery are connected in series in sequence to form a charging loop.

[0010] Furthermore, the model of the ideal diode is MAX40203.

[0011] Furthermore, the output current limiting protection circuit includes a primary current limiting protection circuit and a secondary current limiting protection circuit, the input end of the primary current limiting protection circuit is connected to the output end of the ideal diode, and the output end of the primary current limiting protection circuit is connected to the input end of the secondary current limiting protection circuit.

[0012] Furthermore, the circuit structures of the primary current limiting protection circuit and the secondary current limiting protection circuit are the same.

[0013] Furthermore, the primary current limiting protection circuit includes a resistor R1, a resistor R7, a transistor Q1, a MOS transistor Q3, and a resistor R9. One end of the resistor R1 is grounded, and the other end of the resistor R1 is connected to the base of the transistor Q1. One end of the resistor R7 is grounded, and the other end of the resistor R7 is connected to the base of the transistor Q1. The emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to the G electrode of the MOS transistor Q3, the S electrode of the MOS transistor Q3 is connected to the base of the transistor Q1, and the D electrode of the MOS transistor Q3 is grounded. One end of the resistor R9 is connected to the G electrode of the MOS transistor Q3, and the other end of the resistor R9 outputs a voltage signal.

[0014] By employing the above-mentioned technical solution, the utility model provides overcurrent, overheating, and reverse charging protection for the battery through a combination of diodes and ideal diodes. A triode plus MOS transistor prevents excessive output current and provides current limiting protection for the output power supply. This intrinsically safe design meets explosion-proof requirements, making back-end equipment safer to use. This not only increases battery utilization but also enhances the stability and safety of battery output. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a functional block diagram of the intrinsically safe output circuit of a lithium battery of the present utility model;

[0016] Figure 2 This is a circuit diagram of the charging anti-reverse circuit of the utility model;

[0017] Figure 3 This is a circuit diagram of the overcurrent and overheat protection circuit of the utility model;

[0018] Figure 4 This is a circuit schematic diagram of the output current limiting protection circuit of the utility model. DETAILED DESCRIPTION

[0019] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0020] like Figure 1As shown, this embodiment provides a lithium battery intrinsically safe output circuit, which includes a charging reverse protection circuit, an overcurrent and overheating protection circuit, an output current limiting protection circuit and a plurality of battery packs connected in series.

[0021] like Figure 2 As shown, this embodiment uses two battery packs, each consisting of two parallel-connected batteries. The batteries are ER34615 lithium-thionyl chloride disposable batteries, with two packs totaling four batteries. The four batteries (BT1-BT4) are connected to the pin header IN via the JZB1 terminal block.

[0022] like Figure 2 As shown, the charging reverse protection circuit of this embodiment is connected to the battery pack via terminal JZB1 and pin IN. Each battery in each battery pack is connected to the charging reverse protection circuit for reverse charging protection. The charging reverse protection circuit includes a current-limiting resistor and a reverse protection diode. The current-limiting resistor, the reverse protection diode, and the positive and negative electrodes of the battery are connected in series to form a charging circuit. The first battery pack consists of battery BT1 and battery BT2 in parallel. The positive and negative electrodes of battery BT1, current-limiting resistor R3, and diode D1 form a charging circuit. The positive and negative electrodes of battery BT2, current-limiting resistor R4, and diode D1 form a charging circuit. Batteries BT2 and BT1 are connected in parallel, and the two batteries share a reverse protection diode D1 to prevent reverse charging between the batteries. The second battery pack consists of battery BT3 and battery BT4 in parallel. Batteries BT3 and BT4 share a reverse protection diode D2 to prevent reverse charging between the batteries. The negative electrode of battery BT2 is connected to the positive electrode of battery BT3, completing the series connection of the two battery packs.

[0023] like Figure 1 As shown, each battery in each battery pack of this embodiment is connected to an overcurrent and overheat protection circuit, which includes an ideal diode. The battery is connected to the input end of the ideal diode, and the output end of the ideal diode is connected to the input end of the output current limiting protection circuit. The two ideal diodes in the same battery pack are connected in parallel. Figure 3 As shown, the ideal diode model of this embodiment is MAX40203, and each battery is connected to an ideal diode (U1-U4). Each group of two batteries has a positive electrode of battery BT1 connected to pins 1 and 3 of U1, and a positive electrode of battery BT2 connected to pins 1 and 3 of U2. The positive electrode of battery BT3 is connected to pins 1 and 3 of U3, and the positive electrode of battery BT4 is connected to pins 1 and 3 of U4. Pins 2 of U3 and U4 are connected and then grounded. Pins 5 of U3 and U4 are connected to output 3.6V and connected to pins 2 of U1 and U2. Pins 5 of U1 and U2 are connected to output 7.2V to the output current limiting protection circuit.

[0024] The MAX40203 ideal diode is an ideal diode current switch with a forward voltage drop an order of magnitude smaller than that of a Schottky diode. When forward biased and enabled, the MAX40203's on-state voltage drop is 90mV while carrying up to 1A of current. During a short circuit or rapid power-up, the device limits its output current to 2A. The MAX40203 implements thermal protection to protect itself and subsequent circuits from overcurrent. This circuit ensures normal and stable battery discharge, avoiding overheating and overcurrent.

[0025] like Figure 1 As shown, the output current limiting protection circuit of this embodiment includes a primary current limiting protection circuit and a secondary current limiting protection circuit. The input of the primary current limiting protection circuit is connected to the output of the ideal diode, and the output of the primary current limiting protection circuit is connected to the input of the secondary current limiting protection circuit. A two-stage current limiting protection circuit is used to provide current limiting protection for the power supply output of the ideal diode. The current limiting protection circuit uses a transistor plus a MOS transistor to limit current, preventing excessive output current. The intrinsically safe design, in accordance with explosion-proof requirements, ensures safe and reliable use of downstream equipment.

[0026] The circuit structures of the primary current limiting protection circuit and the secondary current limiting protection circuit of this embodiment are the same. The primary current limiting protection circuit is used as an example for description below:

[0027] like Figure 4 As shown, the primary current limiting protection circuit includes resistor R1, resistor R7, transistor Q1, MOS transistor Q3, and resistor R9. One end of resistor R1 is grounded, and the other end is connected to the base of transistor Q1. One end of resistor R7 is grounded, and the other end is connected to the base of transistor Q1. The emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to the G terminal of MOS transistor Q3, the S terminal of MOS transistor Q3 is connected to the base of transistor Q1, and the D terminal of MOS transistor Q3 is grounded. One end of resistor R9 is connected to the G terminal of MOS transistor Q3, and the other end of resistor R9 outputs a voltage signal. Transistor Q1 uses an S8050, and MOS transistor Q3 uses an FDD8796, with a power of 8W.

[0028] R1 and R7 are current sampling resistors. When the current in the circuit is low, the voltages at the G and S poles of MOS transistor Q3 exceed the turn-on voltage, causing the D and S poles to conduct, and the on-resistance to be very low. When the voltage across R1 exceeds the transistor's base and emitter turn-on voltage, the transistor's collector and emitter conduct, causing the voltages at the G and S poles of the MOS transistor to approach the turn-on voltage. This increases the on-resistance between the D and S poles, increasing the loop resistance and preventing the current from increasing, thus achieving current limiting.

[0029] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lithium battery intrinsically safe output circuit, characterized by: It includes a charge reverse protection circuit, an overcurrent and overheat protection circuit, an output current limiting protection circuit and a plurality of battery packs connected in series, each of which includes two batteries connected in parallel; Each battery in each of the battery packs is connected to a charge reverse protection circuit; Each battery in each battery pack is connected to an overcurrent and overheating protection circuit, which includes an ideal diode. The battery is connected to the input end of the ideal diode, and the output end of the ideal diode is connected to the input end of the output current limiting protection circuit. The two ideal diodes in the same battery pack are connected in parallel.

2. The lithium battery intrinsically safe output circuit according to claim 1, characterized in that: The charging anti-reverse circuit includes a current limiting resistor and an anti-reverse diode, and the current limiting resistor, the anti-reverse diode and the positive and negative electrodes of the battery are sequentially connected in series to form a charging loop.

3. The lithium battery intrinsically safe output circuit according to claim 1, characterized in that: The model of the ideal diode is MAX40203.

4. The lithium battery intrinsically safe output circuit according to claim 1, characterized in that: The output current limiting protection circuit includes a primary current limiting protection circuit and a secondary current limiting protection circuit. The input end of the primary current limiting protection circuit is connected to the output end of the ideal diode, and the output end of the primary current limiting protection circuit is connected to the input end of the secondary current limiting protection circuit.

5. The lithium battery intrinsically safe output circuit according to claim 4, characterized in that: The circuit structures of the primary current limiting protection circuit and the secondary current limiting protection circuit are the same.

6. The lithium battery intrinsically safe output circuit according to claim 4, characterized in that: The primary current limiting protection circuit includes a resistor R1, a resistor R7, a transistor Q1, a MOS transistor Q3, and a resistor R9. One end of the resistor R1 is grounded, and the other end of the resistor R1 is connected to the base of the transistor Q1. One end of the resistor R7 is grounded, and the other end of the resistor R7 is connected to the base of the transistor Q1. The emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to the G electrode of the MOS transistor Q3, the S electrode of the MOS transistor Q3 is connected to the base of the transistor Q1, and the D electrode of the MOS transistor Q3 is grounded. One end of the resistor R9 is connected to the G electrode of the MOS transistor Q3, and the other end of the resistor R9 outputs a voltage signal.

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