Lithium titanate battery charge and discharge protection circuit and power supply device

Abstract

The utility model discloses a lithium titanate battery charge -discharge protection circuit and power supply device relates to power charge -discharge management technical field. Lithium titanate battery charge -discharge protection circuit includes: main control circuit, voltage detection circuit is used for detecting the power end of series battery pack and exports voltage detection signal, first switch circuit, second switch circuit, voltage clamping circuit is used for limiting the charging voltage of series battery pack in the preset voltage range, one -way conduction circuit is used for limiting the charge -discharge current flow direction of series battery pack, wherein, main control circuit is used for receiving voltage detection signal, and control first switch circuit and the on -off state of second switch circuit. The utility model aims at the charging voltage of series battery pack is limited in the corresponding preset voltage range effectively and flexibly, to avoid the invalidation of charge management because of the voltage of series battery pack and the voltage of conventional standard pressure are not identical.

Description

Technical Field

[0001] This utility model relates to the field of power supply charging and discharging management technology, and in particular to a lithium titanate battery charging and discharging protection circuit and power supply device. Background Technology

[0002] In existing technologies, power management chips are typically used to ensure battery safety, monitoring battery voltage and current in real time to prevent overcharging, over-discharging, and overcurrent. However, current battery management chips are designed for batteries with specific voltages, such as 4.2V standard voltage lithium batteries. Some batteries have a standard voltage other than 4.2V, making them unsuitable for these chips. Understandably, existing battery management chips lack flexibility and cannot adapt to different battery voltages. Utility Model Content

[0003] The main purpose of this utility model is to provide a charging and discharging protection circuit and power supply for lithium titanate batteries, which aims to flexibly and effectively limit the charging voltage of the series battery pack within the corresponding preset voltage range, so as to avoid charging management failure due to the inconsistency between the standard voltage of the series battery pack and the conventional standard voltage.

[0004] To achieve the above objectives, this utility model proposes a lithium titanate battery charge / discharge protection circuit, which includes: Main control circuit; A voltage detection circuit is provided, wherein the input terminal of the voltage detection circuit is electrically connected to the power supply terminal of the series-connected battery pack, and the output terminal of the voltage detection circuit is electrically connected to the main control circuit; the voltage detection circuit is used to detect the power supply terminal of the series-connected battery pack and output a voltage detection signal. A first switching circuit, wherein a first terminal of the first switching circuit is electrically connected to the power supply terminal of the series battery pack, a second terminal of the first switching circuit is electrically connected to the positive terminal of the series battery pack, and a controlled terminal of the first switching circuit is electrically connected to the main control circuit. The second switching circuit has a first terminal electrically connected to the positive terminal of the series battery pack, and a controlled terminal electrically connected to the controlled terminal of the first switching circuit. A voltage clamping circuit, wherein the first terminal of the voltage clamping circuit is electrically connected to the second terminal of the second switching circuit, and the second terminal of the voltage clamping circuit is electrically connected to the negative terminal of the series battery pack; the voltage clamping circuit is used to limit the charging voltage of the series battery pack within a preset voltage range; A unidirectional conduction circuit, wherein the first terminal of the unidirectional conduction circuit is electrically connected to the positive terminal of the series battery pack, and the second terminal of the unidirectional conduction circuit is electrically connected to the second terminal of the first switching circuit; the unidirectional conduction circuit is used to limit the direction of charging and discharging current of the series battery pack. The main control circuit is used to receive the voltage detection signal and control the conduction state of the first switching circuit and the second switching circuit.

[0005] In one embodiment, the first switching circuit includes a first switching transistor, a first resistor, and a second resistor; Wherein, the first end of the first switch is electrically connected to the power supply terminal of the series battery pack, the second end of the first switch is electrically connected to the first end of the first resistor and the positive terminal of the series battery pack, the controlled end of the first switch is electrically connected to the second end of the first resistor and the first end of the second resistor, and the second end of the second resistor is electrically connected to the main control circuit.

[0006] In one embodiment, the second switching circuit includes a second switching transistor, a third resistor, a fourth resistor, and a fifth resistor; Wherein, the first end of the third resistor is electrically connected to the positive terminal of the series battery pack and the first end of the fourth resistor; the second end of the third resistor is electrically connected to the second end of the first switching circuit; the second end of the fourth resistor is electrically connected to the first end of the second switching transistor; the second end of the second switching transistor is electrically connected to the first end of the voltage clamping circuit; the controlled end of the second switching transistor is electrically connected to the first end of the fifth resistor; the second end of the fifth resistor is electrically connected to the second end of the second resistor and the main control circuit.

[0007] In one embodiment, the series battery pack includes a first battery cell and a second battery cell, the negative terminal of the first battery cell is electrically connected to the positive terminal of the second battery cell, and the negative terminal of the second battery cell is electrically connected to a ground terminal; the voltage clamping circuit includes a first voltage clamping circuit and a second voltage clamping circuit; the second switching circuit includes: a second switching transistor, a third resistor, a fourth resistor, a fifth resistor, a third switching transistor, a sixth resistor, and a seventh resistor; Wherein, the first end of the third resistor is electrically connected to the positive terminal of the first battery cell and the first end of the fourth resistor; the second end of the third resistor is electrically connected to the second end of the first switching circuit; the second end of the fourth resistor is electrically connected to the first end of the second switching transistor; the second end of the second switching transistor is electrically connected to the first end of the first voltage clamping circuit; the controlled end of the second switching transistor is electrically connected to the first end of the fifth resistor; the second end of the fifth resistor is electrically connected to the second end of the seventh resistor, the second end of the second resistor, and the main control circuit; the first end of the sixth resistor is electrically connected to the second end of the first voltage clamping circuit and the negative terminal of the first battery cell; the second end of the sixth resistor is electrically connected to the first end of the third switching transistor; the second end of the third switching transistor is electrically connected to the second voltage clamping circuit; the controlled end of the third switching transistor is electrically connected to the first end of the seventh resistor; the second end of the second voltage clamping circuit is electrically connected to the ground terminal.

[0008] In one embodiment, the voltage clamping circuit includes at least one of a voltage reference chip and a Zener diode.

[0009] In one embodiment, the unidirectional conduction circuit includes a diode, the anode of which is electrically connected to the positive terminal of the series battery pack, and the cathode of which is electrically connected to the second terminal of the first switching circuit.

[0010] In one embodiment, the lithium titanate battery charge / discharge protection circuit further includes a clock circuit. The power supply terminal of the clock circuit is electrically connected to the positive terminal of the series-connected battery pack, and the output terminal of the clock circuit is electrically connected to the main control circuit. The clock circuit is used to output a clock signal. The main control circuit is used to receive the voltage detection signal and the clock signal to control the first switching circuit and the second switching circuit to disconnect.

[0011] In one embodiment, the lithium titanate battery charge / discharge protection circuit further includes a third switching circuit. The first terminal of the third switching circuit is electrically connected to the controlled terminal of the first switching circuit and the controlled terminal of the second switching circuit. The second terminal of the third switching circuit is electrically connected to a ground terminal. The controlled terminal of the third switching circuit is electrically connected to the main control circuit. The third switching circuit is used to receive a switching control signal output by the main control circuit to correspondingly connect or disconnect the path between the controlled terminal of the first switching circuit, the controlled terminal of the second switching circuit, and the ground terminal.

[0012] In one embodiment, the lithium titanate battery charge / discharge protection circuit further includes a voltage conversion circuit. The first terminal of the voltage conversion circuit is electrically connected to an external power input terminal, and the second terminal of the voltage conversion circuit is electrically connected to the power supply terminal of the series-connected battery pack. The voltage conversion circuit is used to convert the first voltage input to the external power input terminal into a second voltage and output it. The input terminal of the voltage detection circuit is electrically connected to the first terminal of the voltage conversion circuit.

[0013] This utility model also proposes a power supply device, which includes a series battery pack and a lithium titanate battery charge and discharge protection circuit as described in any of the above claims.

[0014] This invention employs a lithium titanate battery charge / discharge protection circuit, which can flexibly and effectively limit the charging voltage of a series-connected battery pack within a corresponding preset voltage range. This avoids charging management failures due to inconsistencies between the standard voltage of the series-connected battery pack and the conventional standard voltage, thereby preventing safety risks associated with the series-connected battery pack during charging. A voltage detection circuit detects the power supply terminal of the series-connected battery pack and outputs a corresponding voltage detection signal to the main control circuit, allowing the main control circuit to confirm the charging / discharging state of the series-connected battery pack based on the voltage detection signal. When the main control circuit confirms that the series-connected battery pack is in a charging / discharging state based on the voltage detection signal, it outputs corresponding switch control signals to the first and second switch circuits, causing the first and second switch circuits to conduct. This allows the voltage clamping circuit to limit the charging voltage of the series-connected battery pack within the preset voltage range. When the series-connected battery pack is in a discharging state, power can be output to the power supply terminal through a unidirectional conduction circuit. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the charging and discharging protection circuit for lithium titanate batteries according to this utility model. Figure 2 This is a schematic diagram of a module of an embodiment of the lithium titanate battery charge and discharge protection circuit of this utility model; Figure 3 This is a circuit diagram of the lithium titanate battery charge and discharge protection circuit of this utility model.

[0017] Explanation of icon numbers: 10. Main control circuit; 20. Voltage detection circuit; 30. First switching circuit; 40. Second switching circuit; 50. Voltage clamping circuit; 60. One-way conduction circuit; 70. Third switching circuit; 80. Clock circuit; 90. Voltage conversion circuit; R1-R9, first resistor-ninth resistor; D1, first voltage clamping circuit; D2, second voltage clamping circuit; Q1-Q4, first switching transistor-fourth switching transistor.

[0018] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0021] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0022] In existing technologies, power management chips are typically used to ensure battery safety, monitoring battery voltage and current in real time to prevent overcharging, over-discharging, and overcurrent. However, current battery management chips are designed for batteries with specific voltages, such as 4.2V standard voltage lithium batteries. Some batteries have a standard voltage other than 4.2V, making them unsuitable for these chips. Understandably, existing battery management chips lack flexibility and cannot adapt to different battery voltages.

[0023] To solve the above problems, refer to Figure 1 and Figure 3 This utility model proposes a charging and discharging protection circuit for a lithium titanate battery, the lithium titanate battery charging and discharging protection circuit comprising: Main control circuit 10; A voltage detection circuit 20 is provided, wherein the input terminal of the voltage detection circuit 20 is electrically connected to the power supply terminal of the series battery pack, and the output terminal of the voltage detection circuit 20 is electrically connected to the main control circuit 10; the voltage detection circuit 20 is used to detect the power supply terminal of the series battery pack and output a voltage detection signal. A first switching circuit 30, wherein a first terminal of the first switching circuit 30 is electrically connected to the power supply terminal of the series battery pack, a second terminal of the first switching circuit 30 is electrically connected to the positive terminal of the series battery pack, and a controlled terminal of the first switching circuit 30 is electrically connected to the main control circuit 10. The second switching circuit 40 has its first terminal electrically connected to the positive terminal of the series battery pack, and its controlled terminal electrically connected to the controlled terminal of the first switching circuit 30. A voltage clamping circuit 50 is provided, wherein a first terminal of the voltage clamping circuit 50 is electrically connected to a second terminal of the second switching circuit 40, and a second terminal of the voltage clamping circuit 50 is electrically connected to the negative terminal of the series battery pack; the voltage clamping circuit 50 is used to limit the charging voltage of the series battery pack within a preset voltage range. A unidirectional conduction circuit 60 is provided, wherein a first terminal of the unidirectional conduction circuit 60 is electrically connected to the positive terminal of the series battery pack, and a second terminal of the unidirectional conduction circuit 60 is electrically connected to the second terminal of the first switching circuit 30; the unidirectional conduction circuit 60 is used to limit the direction of charging and discharging current of the series battery pack. The main control circuit 10 is used to receive the voltage detection signal and control the conduction state of the first switching circuit 30 and the second switching circuit 40.

[0024] In this embodiment, the main control circuit 10 can be implemented using FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), MCU (Microcontroller Unit), DSP (Digital Signal Processor), or SOC (System on Chip). The control circuit in the lithium titanate battery charge / discharge protection circuit is mainly responsible for coordinating and controlling the data acquisition, processing, decision-making, and response of various circuits and modules. The choice of main controller directly affects the system's performance, cost, power consumption, and development flexibility. In practical applications, the choice depends on the specific application scenario, such as processing speed, power consumption limits, cost budget, development cycle, and system scalability.

[0025] In this embodiment, the voltage detection circuit 20 can be implemented using a voltage divider resistor circuit, an operational amplifier detection circuit, a comparator circuit, etc. The input terminal of the voltage detection circuit 20 is electrically connected to the power supply terminal of the series-connected battery pack, thereby detecting the voltage at the power supply terminal of the series-connected battery pack. The output terminal of the voltage detection circuit 20 is electrically connected to the main control circuit 10, outputting a voltage detection signal to the main control circuit 10. The main control circuit 10 then uses the voltage detection signal to determine the charging and discharging state of the series-connected battery pack. It should be noted that the charging and discharging voltages of the series-connected battery pack are not the same. For example, the charging voltage of the series-connected battery pack is 5.5V, but the output voltage may be 5.3V. Therefore, by detecting the voltage at the power supply terminal of the series-connected battery pack through the voltage detection circuit 20, the main control circuit 10 can determine whether the power supply terminal of the series-connected battery pack is connected to an external power source and whether the series-connected battery pack is in a discharging state.

[0026] In this embodiment, the first switching circuit 30 can be implemented using at least one switching transistor, such as a MOSFET or an IGBT. The first terminal of the first switching circuit 30 is electrically connected to the power supply terminal of the series-connected battery pack, the second terminal of the first switching circuit 30 is electrically connected to the positive terminal of the series-connected battery pack, and the controlled terminal of the first switching circuit 30 is electrically connected to the main control circuit 10. This allows the circuit to be opened or closed when the main control circuit 10 outputs a corresponding switching control signal, thus enabling the connection between the power supply terminal of the series-connected battery pack and the positive terminal of the series-connected battery pack to be made open or closed.

[0027] Optionally, the first switching circuit 30 includes a first switching transistor Q1, a first resistor R1, and a second resistor R2. The first terminal of the first switching transistor Q1 is electrically connected to the power supply terminal of the battery, the second terminal of the first switching transistor Q1 is electrically connected to the first terminal of the first resistor R1 and the positive terminal of the battery, the controlled terminal of the first switching transistor Q1 is electrically connected to the second terminal of the first resistor R1 and the first terminal of the second resistor R2, and the second terminal of the second resistor R2 is electrically connected to the main control circuit 10. It should be noted that the first switching circuit 30 needs to be implemented using a switching transistor with a body diode. Therefore, the first switching transistor Q1 can be implemented using a MOSFET or an IGBT, etc. When an external power input is present at the power supply terminal of the series-connected battery pack, the external power input can charge the battery through the body diode of the first switch transistor Q1. Furthermore, when the main control circuit 10 detects the external power input through the voltage detection circuit 20, it controls the first switch transistor Q1 to be fully turned on. When the series-connected battery pack needs to output power through the power supply terminal, the main control circuit 10 can control the first switch transistor Q1 in the first switching circuit 30 to be turned on, thereby realizing the output power. Here, the first resistor R1 is the driving resistor, and the second resistor R2 is the pull-down resistor.

[0028] In this embodiment, the second switching circuit 40 can be implemented using at least one switching transistor, such as a MOSFET, IGBT, thyristor, transistor, or power transistor, and / or using at least one switching device, such as a contactor, circuit breaker, or relay. The first terminal of the second switching circuit 40 is electrically connected to the positive terminal of the series-connected battery pack, the second terminal of the second switching circuit 40 is electrically connected to the voltage clamping circuit 50, the controlled terminal of the second switching circuit 40 is electrically connected to the main control circuit 10, and the second terminal of the voltage clamping circuit 50 is electrically connected to the negative terminal of the series-connected battery pack. In this way, the voltage clamping circuit 50 clamps the positive and negative terminals of the series-connected battery pack, thereby enabling the voltage detection signal to confirm that the series-connected battery pack is in a charging / discharging state when an external power source charges and discharges the series-connected battery pack, and thus controlling the second switching circuit 40 to open the path between the positive and negative terminals of the series-connected battery pack and the voltage clamping circuit 50. When the series battery pack is not in a charging state, the voltage detection signal confirms that the series battery pack is not in a charging state, thereby controlling the second switch circuit 40 to disconnect the path between the positive and negative terminals of the series battery pack and the voltage clamping circuit 50, thereby preventing the series battery pack from consuming power on the voltage clamping circuit 50.

[0029] Optionally, the second switching circuit 40 includes a second switching transistor Q2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5; wherein, the first terminal of the third resistor R3 is electrically connected to the positive terminal of the series battery pack and the first terminal of the fourth resistor R4, and the second terminal of the third resistor R3 is electrically connected to the second terminal of the first switching circuit 30; the second terminal of the fourth resistor R4 is electrically connected to the first terminal of the second switching transistor Q2; the second terminal of the second switching transistor Q2 is electrically connected to the first terminal of the voltage clamping circuit 50, and the controlled terminal of the second switching transistor Q2 is electrically connected to the first terminal of the fifth resistor R5; the second terminal of the fifth resistor R5 is electrically connected to the second terminal of the second resistor R2 and the main control circuit 10. In this embodiment, the second switching transistor Q2 in the second switching circuit 40 is implemented using the same switching transistor as the first switching transistor Q1, thereby enabling the first switching transistor Q1 and the second switching transistor Q2 to be simultaneously turned on or off by outputting the same switching control signal from the main control circuit 10. It is understandable that both the first switching circuit 30 and the second switching circuit 40 are turned on when the series-connected battery pack is charging, and turned off when the series-connected battery pack is discharging. The third resistor R3 and the fourth resistor R4 are current-limiting resistors, and the fifth resistor R5 is a pull-down resistor.

[0030] In this embodiment, the voltage clamping circuit 50 can be implemented using a voltage reference chip, a Zener diode, or similar means. By connecting the two ends of the voltage clamping circuit 50 in parallel with the positive and negative terminals of the series-connected battery pack, the charging and discharging voltage of the series-connected battery pack is limited to a preset voltage range. Taking the voltage clamping circuit 50 implemented using a voltage reference chip as an example, the voltage reference chip can provide a very stable and accurate reference voltage. The voltage between its reference terminal and cathode is precisely maintained at a fixed value, such as 2.5V. Because there are voltage drops across the first resistor R1, the third resistor R3, and the eighth resistor R8, the 2.5V of the voltage reference chip, combined with the voltage drop across the third resistor R3, equals the maximum voltage of each battery cell, close to 2.726V. This ensures that the maximum voltage of the series-connected battery pack during charging will not exceed a safe range, thus providing overvoltage protection.

[0031] In this embodiment, the unidirectional conduction circuit 60 includes a diode, the anode of which is electrically connected to the positive terminal of the series battery pack, and the cathode of which is electrically connected to the second terminal of the first switching circuit 30. When there is no external power supply connected to the power supply terminal of the series battery pack, and the first switching circuit 30 is in the on state, the series battery pack can output power to the power supply terminal through the unidirectional conduction circuit 60.

[0032] This invention employs a lithium titanate battery charge / discharge protection circuit, which can flexibly and effectively limit the charging voltage of a series-connected battery pack within a corresponding preset voltage range. This avoids charging management failure due to inconsistencies between the standard voltage of the series-connected battery pack and the conventional standard voltage, thereby preventing safety risks associated with the series-connected battery pack during charging. A voltage detection circuit 20 detects the power supply terminal of the series-connected battery pack and outputs a corresponding voltage detection signal to the main control circuit 10, allowing the main control circuit 10 to confirm the charging / discharging state of the series-connected battery pack based on the voltage detection signal. When the main control circuit 10 confirms that the series-connected battery pack is in a charging / discharging state based on the voltage detection signal, it outputs corresponding switch control signals to the first switch circuit 30 and the second switch circuit 40, causing the first switch circuit 30 and the second switch circuit 40 to conduct, thereby limiting the charging voltage of the series-connected battery pack within the preset voltage range using a voltage clamping circuit 50. When the series-connected battery pack is in a discharging state, power can be output to the power supply terminal through a unidirectional conduction circuit 60.

[0033] refer to Figure 1 and Figure 3 In one embodiment of this utility model, the series battery pack includes a first battery unit and a second battery unit, the negative terminal of the first battery unit is electrically connected to the positive terminal of the second battery unit, and the negative terminal of the second battery unit is electrically connected to the ground terminal; the voltage clamping circuit 50 includes a first voltage clamping circuit D1 and a second voltage clamping circuit D2; the second switching circuit 40 includes: a second switching transistor Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a third switching transistor Q3, a sixth resistor R6, and a seventh resistor R7; Wherein, the first end of the third resistor R3 is electrically connected to the positive terminal of the first battery cell and the first end of the fourth resistor R4; the second end of the third resistor R3 is electrically connected to the second end of the first switching circuit 30; the second end of the fourth resistor R4 is electrically connected to the first end of the second switching transistor Q2; the second end of the second switching transistor Q2 is electrically connected to the first end of the first voltage clamping circuit D1; the controlled end of the second switching transistor Q2 is electrically connected to the first end of the fifth resistor R5; the second end of the fifth resistor R5 is electrically connected to the second end of the seventh resistor R7, the second end of the second resistor R2, and the main control circuit 10; the first end of the sixth resistor R6 is electrically connected to the second end of the first voltage clamping circuit D1 and the negative terminal of the first battery cell; the second end of the sixth resistor R6 is electrically connected to the first end of the third switching transistor Q3; the second end of the third switching transistor Q3 is electrically connected to the second voltage clamping circuit D2; the controlled end of the third switching transistor Q3 is electrically connected to the first end of the seventh resistor R7; the second end of the second voltage clamping circuit D2 is electrically connected to the ground terminal.

[0034] It's understandable that most existing series-connected battery packs use a single battery management chip to manage all the battery cells in the pack. One end of the chip is connected to the positive terminal of the overall output of the pack, and the other end to the negative terminal. It's also understandable that after prolonged use, the individual cells in a series-connected battery pack will experience varying degrees of capacity degradation. This means that during series charging, some cells may be fully charged while others are not. This results in a situation where the overall voltage of the series-connected battery pack is not overcharged, but some individual cells are overcharged, leading to a reduced lifespan and potential safety issues.

[0035] In this embodiment, the series-connected battery pack includes a first battery cell and a second battery cell, which are connected in series. The first terminal of the first voltage clamping circuit D1 is electrically connected to the second terminal of the second switch Q2, and the second terminal of the first voltage clamping circuit D1 is connected to the negative terminal of the first battery cell. The first terminal of the second voltage clamping circuit D2 is electrically connected to the second terminal of the third switch Q3, and the second terminal of the second voltage clamping circuit D2 is connected to ground. By controlling the second switch Q2 and the third switch Q3, the first voltage clamping circuit D1 and the second voltage clamping circuit D2 limit the charging voltage of the first and second battery cells, effectively ensuring the consistency of charging among the batteries in the series-connected battery pack.

[0036] refer to Figure 2 and Figure 3 In one embodiment of this utility model, the lithium titanate battery charge and discharge protection circuit further includes a clock circuit 80. The power supply terminal of the clock circuit 80 is electrically connected to the positive terminal of the series battery pack, and the output terminal of the clock circuit 80 is electrically connected to the main control circuit 10. The clock circuit 80 is used to output a clock signal. The main control circuit 10 is used to receive the voltage detection signal and the clock signal to control the first switching circuit 30 and the second switching circuit 40 to disconnect.

[0037] In this embodiment, the clock circuit 80 outputs a clock signal to the main control circuit 10, so that the main control circuit 10 controls the operating state of the series battery pack according to the clock signal and the voltage detection signal. Specifically, by setting a corresponding preset duration in the main control circuit 10, when the clock signal output by the clock circuit 80 matches the preset duration, the first switch circuit 30 and the second switch circuit 40 are turned off, thereby preventing the series battery pack from being in a continuous discharge state. For example, if the preset duration is set to 10 seconds, then when the voltage detection signal output by the voltage detection circuit 20 corresponds to the series battery pack being in a discharge state, and the clock signal corresponds to 10 seconds, the first switch circuit 30 and the second switch circuit 40 are turned off. At this time, the series battery pack will not be able to output power through the power supply terminal. In addition, the clock circuit 80 can be set at the positive terminal of the corresponding battery cell in the series battery pack according to its own supply voltage, so as to realize the power supply of the series battery pack to the clock circuit 80. The clock circuit includes an eighth resistor R8, which is a load circuit, and the second end of the eighth resistor R8 is electrically connected to the power supply terminal of the clock circuit 80.

[0038] refer to Figure 2 and Figure 3 In one embodiment of this utility model, the lithium titanate battery charge / discharge protection circuit further includes a third switch circuit 70. The first terminal of the third switch circuit 70 is electrically connected to the controlled terminal of the first switch circuit 30 and the controlled terminal of the second switch circuit 40. The second terminal of the third switch circuit 70 is electrically connected to the ground terminal. The controlled terminal of the third switch circuit 70 is electrically connected to the main control circuit 10. The third switch circuit 70 is used to receive the switch control signal output by the main control circuit 10, so as to correspondingly conduct or disconnect the path between the controlled terminal of the first switch circuit 30, the controlled terminal of the second switch circuit 40 and the ground terminal.

[0039] In this embodiment, the third switching circuit 70 can be implemented using at least one switching transistor, such as a MOSFET, IGBT, thyristor, transistor, or power transistor, and / or using at least one switching device, such as a contactor, circuit breaker, or relay. It is understood that the third switching circuit 70 is configured to prevent the output voltage of the series-connected battery pack from reaching the signal terminal of the main control circuit 10. As described above, the positive terminal of the series-connected battery pack is electrically connected to the main control circuit 10 via the third resistor R3, the first resistor R1, and the second resistor R2. Therefore, by configuring the third switching circuit 70, isolation is achieved between the positive terminal of the series-connected battery pack and the signal terminal of the main control circuit 10. The third switching circuit includes a fourth switching transistor Q4 and a ninth resistor R9.

[0040] refer to Figure 2In one embodiment of this utility model, the lithium titanate battery charge and discharge protection circuit further includes a voltage conversion circuit 90. The first terminal of the voltage conversion circuit 90 is electrically connected to the external power input terminal, and the second terminal of the voltage conversion circuit 90 is electrically connected to the power supply terminal of the series battery pack. The voltage conversion circuit 90 is used to convert the first voltage input to the external power input terminal into a second voltage and output it. The input terminal of the voltage detection circuit 20 is electrically connected to the first terminal of the voltage conversion circuit 90.

[0041] In this embodiment, the external power supply voltage connected to the power supply terminal of the series battery pack is not directly input, but is converted and input through the voltage conversion circuit 90. The voltage conversion circuit can be implemented using a boost circuit or a buck circuit, depending on the input external power supply voltage. For example, if the external power supply voltage is 12V (the first voltage is 12V), it needs to be stepped down to the corresponding second voltage to charge the series battery pack. The input terminal of the voltage detection circuit 20 is electrically connected to the first terminal of the voltage conversion circuit 90, thereby detecting the external power supply voltage to confirm whether there is an external power supply input. When the voltage detection signal output by the voltage detection circuit 20 indicates that the external power supply voltage has stopped input, the main control circuit 10 uses the clock signal output by the clock circuit 80 to confirm whether the duration of the external power supply voltage input stoppage has reached a preset duration. When the duration of the external power supply voltage input stoppage reaches the preset duration, the first switch circuit 30 is controlled to turn off, thereby stopping the power output from the series battery pack.

[0042] This utility model also proposes a power supply device, which includes a series battery pack and a lithium titanate battery charge / discharge protection circuit as described in any of the above claims. It is worth noting that since the power supply device of this utility model is based on the aforementioned lithium titanate battery charge / discharge protection circuit, the embodiments of the power supply device of this utility model include all the technical solutions of all embodiments of the aforementioned lithium titanate battery charge / discharge protection circuit, and the achieved technical effects are exactly the same, so they will not be repeated here.

[0043] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A charging and discharging protection circuit for a lithium titanate battery, characterized in that, The lithium titanate battery charge / discharge protection circuit includes: Main control circuit; A voltage detection circuit is provided, wherein the input terminal of the voltage detection circuit is electrically connected to the power supply terminal of the series-connected battery pack, and the output terminal of the voltage detection circuit is electrically connected to the main control circuit; the voltage detection circuit is used to detect the power supply terminal of the series-connected battery pack and output a voltage detection signal. A first switching circuit, wherein a first terminal of the first switching circuit is electrically connected to the power supply terminal of the series battery pack, a second terminal of the first switching circuit is electrically connected to the positive terminal of the series battery pack, and a controlled terminal of the first switching circuit is electrically connected to the main control circuit. The second switching circuit has a first terminal electrically connected to the positive terminal of the series battery pack, and a controlled terminal electrically connected to the controlled terminal of the first switching circuit. A voltage clamping circuit, wherein the first terminal of the voltage clamping circuit is electrically connected to the second terminal of the second switching circuit, and the second terminal of the voltage clamping circuit is electrically connected to the negative terminal of the series battery pack; the voltage clamping circuit is used to limit the charging voltage of the series battery pack within a preset voltage range; A unidirectional conduction circuit, wherein the first terminal of the unidirectional conduction circuit is electrically connected to the positive terminal of the series battery pack, and the second terminal of the unidirectional conduction circuit is electrically connected to the second terminal of the first switching circuit; the unidirectional conduction circuit is used to limit the direction of charging and discharging current of the series battery pack. The main control circuit is used to receive the voltage detection signal and control the conduction state of the first switching circuit and the second switching circuit.

2. The lithium titanate battery charge / discharge protection circuit as described in claim 1, characterized in that, The first switching circuit includes a first switching transistor, a first resistor, and a second resistor; Wherein, the first end of the first switch is electrically connected to the power supply terminal of the series battery pack, the second end of the first switch is electrically connected to the first end of the first resistor and the positive terminal of the series battery pack, the controlled end of the first switch is electrically connected to the second end of the first resistor and the first end of the second resistor, and the second end of the second resistor is electrically connected to the main control circuit.

3. The lithium titanate battery charge / discharge protection circuit as described in claim 2, characterized in that, The second switching circuit includes a second switching transistor, a third resistor, a fourth resistor, and a fifth resistor; Wherein, the first end of the third resistor is electrically connected to the positive terminal of the series battery pack and the first end of the fourth resistor; the second end of the third resistor is electrically connected to the second end of the first switching circuit; the second end of the fourth resistor is electrically connected to the first end of the second switching transistor; the second end of the second switching transistor is electrically connected to the first end of the voltage clamping circuit; the controlled end of the second switching transistor is electrically connected to the first end of the fifth resistor; the second end of the fifth resistor is electrically connected to the second end of the second resistor and the main control circuit.

4. The lithium titanate battery charge / discharge protection circuit as described in claim 2, characterized in that, The series battery pack includes a first battery unit and a second battery unit, wherein the negative terminal of the first battery unit is electrically connected to the positive terminal of the second battery unit, and the negative terminal of the second battery unit is electrically connected to the ground terminal. The voltage clamping circuit includes a first voltage clamping circuit and a second voltage clamping circuit; The second switching circuit includes: a second switching transistor, a third resistor, a fourth resistor, a fifth resistor, a third switching transistor, a sixth resistor, and a seventh resistor; Wherein, the first end of the third resistor is electrically connected to the positive terminal of the first battery cell and the first end of the fourth resistor; the second end of the third resistor is electrically connected to the second end of the first switching circuit; the second end of the fourth resistor is electrically connected to the first end of the second switching transistor; the second end of the second switching transistor is electrically connected to the first end of the first voltage clamping circuit; the controlled end of the second switching transistor is electrically connected to the first end of the fifth resistor; the second end of the fifth resistor is electrically connected to the second end of the seventh resistor, the second end of the second resistor, and the main control circuit; the first end of the sixth resistor is electrically connected to the second end of the first voltage clamping circuit and the negative terminal of the first battery cell; the second end of the sixth resistor is electrically connected to the first end of the third switching transistor; the second end of the third switching transistor is electrically connected to the second voltage clamping circuit; the controlled end of the third switching transistor is electrically connected to the first end of the seventh resistor; the second end of the second voltage clamping circuit is electrically connected to the ground terminal.

5. The lithium titanate battery charge / discharge protection circuit as described in any one of claims 1 to 4, characterized in that, The voltage clamping circuit includes at least one of a voltage reference chip and a Zener diode.

6. The lithium titanate battery charge / discharge protection circuit as described in any one of claims 1 to 4, characterized in that, The unidirectional conduction circuit includes a diode, the anode of which is electrically connected to the positive terminal of the series battery pack, and the cathode of which is electrically connected to the second terminal of the first switching circuit.

7. The lithium titanate battery charge / discharge protection circuit as described in any one of claims 1 to 4, characterized in that, The lithium titanate battery charge / discharge protection circuit also includes a clock circuit. The power supply terminal of the clock circuit is electrically connected to the positive terminal of the series-connected battery pack, and the output terminal of the clock circuit is electrically connected to the main control circuit. The clock circuit is used to output a clock signal. The main control circuit is used to receive the voltage detection signal and the clock signal to control the first switching circuit and the second switching circuit to disconnect.

8. The lithium titanate battery charge / discharge protection circuit as described in claim 4, characterized in that, The lithium titanate battery charge / discharge protection circuit further includes a third switching circuit. The first terminal of the third switching circuit is electrically connected to the controlled terminal of the first switching circuit and the controlled terminal of the second switching circuit. The second terminal of the third switching circuit is electrically connected to the ground terminal. The controlled terminal of the third switching circuit is electrically connected to the main control circuit. The third switching circuit is used to receive the switching control signal output by the main control circuit to correspondingly connect or disconnect the path between the controlled terminal of the first switching circuit, the controlled terminal of the second switching circuit, and the ground terminal.

9. The lithium titanate battery charge / discharge protection circuit as described in claim 7, characterized in that, The lithium titanate battery charge / discharge protection circuit also includes a voltage conversion circuit. The first terminal of the voltage conversion circuit is electrically connected to the external power input terminal, and the second terminal of the voltage conversion circuit is electrically connected to the power supply terminal of the series battery pack. The voltage conversion circuit is used to convert the first voltage input to the external power input terminal into a second voltage and output it. The input terminal of the voltage detection circuit is electrically connected to the first terminal of the voltage conversion circuit.

10. A power supply device, characterized in that, The power supply device includes a series battery pack and a lithium titanate battery charge / discharge protection circuit as described in any one of claims 1 to 9.

Images