Rechargeable battery protection device and battery management system

Abstract

The utility model discloses a protection device of a rechargeable battery and a battery management system, and belongs to the technical field of power electronics, the protection device comprises an analog chip, a control chip, a watchdog chip, a level conversion module, a three-terminal fuse and two controllable switches; wherein the first end of the three-end fuse is connected with the positive electrode of the rechargeable battery, the third end of the three-end fuse is connected with the first end of the first controllable switch and the first end of the second controllable switch, and the second end of the first controllable switch and the second end of the second controllable switch are both connected with the negative electrode of the rechargeable battery. The control end of the first controllable switch is connected with the control chip, the control end of the second controllable switch is connected with the output end of the level conversion module, and the two input ends of the level conversion module are connected with the fault output pin of the analog chip and the output end of the watchdog chip respectively. Through the protection device, the safety of the rechargeable battery in the operation process can be further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and in particular to a protection device for a rechargeable battery and a battery management system. Background Art

[0002] In order to ensure the safe and stable operation of rechargeable batteries, people usually use analog chips to monitor the operating status of rechargeable batteries. When the analog chip detects that the operating status of the rechargeable battery is abnormal, the control chip at the back end of the analog chip will control the three-terminal fuse in the control circuit where the rechargeable battery is located to fuse, so as to disconnect the control circuit where the rechargeable battery is located, thereby achieving the purpose of protecting the rechargeable battery.

[0003] However, once the control chip fails, the three-terminal fuse in the control circuit where the rechargeable battery is located cannot be controlled. When the rechargeable battery is operating abnormally, it is very easy to cause permanent damage to the rechargeable battery or cause safety accidents such as explosion. At present, there is no effective solution to this technical problem.

[0004] It can be seen that how to further improve the safety of rechargeable batteries during operation is a technical problem that needs to be urgently solved by those skilled in the art. Utility Model Content

[0005] In view of this, the purpose of the utility model is to provide a protection device for a rechargeable battery and a battery management system to solve the technical problem in the prior art that the safe operation of the rechargeable battery cannot be guaranteed when the control chip fails. The specific scheme is as follows:

[0006] In order to solve the above technical problems, the utility model provides a protection device for a rechargeable battery, comprising: an analog chip for monitoring the operating state of the rechargeable battery, a control chip communicatively connected to the analog chip, a watchdog chip for monitoring the operating state of the control chip, a level conversion module for correspondingly outputting a high level signal only when two low level signals are received, a three-terminal fuse, a first controllable switch and a second controllable switch;

[0007] Wherein, the first end of the three-terminal fuse is connected to the positive electrode of the rechargeable battery, the third end of the three-terminal fuse is respectively connected to the first end of the first controllable switch and the first end of the second controllable switch, the second end of the first controllable switch and the second end of the second controllable switch are both connected to the negative electrode of the rechargeable battery, the control end of the first controllable switch is connected to the control chip, the control end of the second controllable switch is connected to the output end of the level conversion module, and the two input ends of the level conversion module are respectively connected to the fault output pin of the analog chip and the output end of the watchdog chip;

[0008] Correspondingly, the second end of the three-terminal fuse is the positive output end of the entire circuit, and the negative electrode of the rechargeable battery is the negative output end of the entire circuit.

[0009] Preferably, the level conversion module is specifically a NAND gate circuit.

[0010] Preferably, the first controllable switch and the second controllable switch are respectively a first NMOS transistor and a second NMOS transistor;

[0011] Correspondingly, the drain of the first NMOS tube is the first end of the first controllable switch, the source of the first NMOS tube is the second end of the first controllable switch, the gate of the first NMOS tube is the control end of the first controllable switch, the drain of the second NMOS tube is the first end of the second controllable switch, the source of the second NMOS tube is the second end of the second controllable switch, and the gate of the second NMOS tube is the control end of the second controllable switch.

[0012] Preferably, it also includes: a DC / DC conversion circuit for powering the control chip;

[0013] Wherein, the input end of the DC / DC conversion circuit is connected to the second end of the three-terminal fuse, and the output end of the DC / DC conversion circuit is connected to the control chip.

[0014] Preferably, the DC / DC conversion circuit is specifically a BUCK circuit.

[0015] Preferably, it further comprises: a first resistor, a third controllable switch and a fourth controllable switch;

[0016] Wherein, the first end of the first resistor is connected to the negative electrode of the rechargeable battery, the second end of the first resistor is connected to the second end of the third controllable switch, and the first end of the third controllable switch is connected to the first end of the fourth controllable switch;

[0017] Correspondingly, the control end of the third controllable switch and the control end of the fourth controllable switch are both connected to the control chip; and the second end of the fourth controllable switch is correspondingly replaced by the negative output end of the entire circuit.

[0018] Preferably, it further comprises: a second resistor and a fifth controllable switch;

[0019] Among them, the first end of the second resistor is connected to the second end of the first resistor, the second end of the second resistor is connected to the second end of the fifth controllable switch, the first end of the fifth controllable switch is connected to the first end of the fourth controllable switch, and the control end of the fourth controllable switch is connected to the control chip.

[0020] Preferably, it further comprises: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and a second capacitor;

[0021] The second end of the third resistor is respectively connected to the first end of the first capacitor, the first end of the fourth resistor and the control end of the first controllable switch, and the second end of the first capacitor and the second end of the fourth resistor are both connected to the second end of the first controllable switch; the control end of the second controllable switch is respectively connected to the first end of the fifth resistor, the first end of the second capacitor and the first end of the sixth resistor, and the second end of the second controllable switch, the second end of the fifth resistor and the second end of the second capacitor are all grounded;

[0022] Correspondingly, a first end of the third resistor is connected to the control chip, and a second end of the sixth resistor is connected to the output end of the level conversion module.

[0023] Preferably, it further comprises: a seventh resistor and a third capacitor;

[0024] Wherein, the first end of the seventh resistor is connected to the first end of the third capacitor, the second end of the seventh resistor is grounded, and the second end of the third capacitor is connected to the first end of the third resistor;

[0025] Correspondingly, the first end of the seventh resistor is connected to the control chip.

[0026] In order to solve the above technical problems, the utility model also provides a battery management system, including a protection device for a rechargeable battery as disclosed above.

[0027] Beneficial effect: In the rechargeable battery protection device provided in the present application, when the control chip is operating normally, if the analog chip detects that the operating state of the rechargeable battery is abnormal, the control chip will output a control signal to the first controllable switch to blow the three-terminal fuse, thereby achieving the purpose of protecting the rechargeable battery. When the control chip fails, if the analog chip detects that the operating state of the rechargeable battery is abnormal, the fault output pin of the analog chip will output a low-level signal, and the watchdog chip will also output a low-level signal because it detects that the control chip fails. In this case, the level conversion module will output a high-level signal and trigger the second controllable switch to blow the three-terminal fuse, thereby achieving the purpose of protecting the rechargeable battery. Obviously, the rechargeable battery protection device provided by the present application can further improve the safety of the rechargeable battery during operation. Correspondingly, a battery management system provided by the present application also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 A structural diagram of a protection device for a rechargeable battery provided by an embodiment of the utility model;

[0030] Figure 2 A structural diagram of another rechargeable battery protection device provided by an embodiment of the utility model;

[0031] Figure 3 This is a structural diagram of another rechargeable battery protection device provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] See also Figure 1 , Figure 1 The structure diagram of a protection device for a rechargeable battery provided by an embodiment of the utility model, the protection device comprises: an analog chip 101 for monitoring the operating state of a rechargeable battery 100, a control chip 102 communicatively connected to the analog chip 101, a watchdog chip 103 for monitoring the operating state of the control chip 102, a level conversion module 104 for outputting a high level signal only when two low level signals are received, a three-terminal fuse M, a first controllable switch Q1 and a second controllable switch Q2;

[0034] Wherein, a first end of the three-terminal fuse M is connected to the positive electrode B+ of the rechargeable battery 100, a third end of the three-terminal fuse M is respectively connected to the first end of the first controllable switch Q1 and the first end of the second controllable switch Q2, a second end of the first controllable switch Q1 and a second end of the second controllable switch Q2 are both connected to the negative electrode B- of the rechargeable battery 100, a control end of the first controllable switch Q1 is connected to the control chip 102, a control end of the second controllable switch Q2 is connected to the output end of the level conversion module 104, and two input ends of the level conversion module 104 are respectively connected to the fault output pin of the analog chip 101 and the output end of the watchdog chip 103;

[0035] Correspondingly, the second end of the three-terminal fuse M is the positive output end P+ of the entire circuit, and the negative electrode of the rechargeable battery 100 is the negative output end P- of the entire circuit.

[0036] In such Figure 1 In the protection device shown, the level conversion module 104 outputs a high level signal only when receiving two low level signals, and outputs a low level signal in other states. When the analog chip 101 detects that the rechargeable battery 100 is operating normally, if the control chip 102 is operating normally, the control chip 102 will output a low level signal, and the first controllable switch Q1 is in the off state. At the same time, the fault output pin NFAULT of the analog chip 101 outputs a high level signal, and the watchdog chip 103 also outputs a high level signal. When the fault output pin NFAULT of the analog chip 101 outputs a high level signal, and the watchdog chip 103 outputs a high level signal, the two will output a low level signal through the level conversion module 104, and the second controllable switch Q2 is in the off state.

[0037] When the analog chip 101 detects that the rechargeable battery 100 is operating abnormally, if the control chip 102 is operating normally, the control chip 102 will send a PWM (Pulsewidth modulation) wave to the first controllable switch Q1 to trigger the first controllable switch Q1 to turn on according to the information monitored by the analog chip 101. After the first controllable switch Q1 is turned on, the three-terminal fuse M will be blown, so that the purpose of protecting the rechargeable battery 100 can be achieved.

[0038] When the analog chip 101 detects that the rechargeable battery 100 is operating abnormally, if the control chip 102 fails, the fault output pin NFAULT of the analog chip 101 will output a low level signal. At the same time, the watchdog chip 103 will output a low level signal because it detects that the control chip 102 fails. When the fault output pin NFAULT of the analog chip 101 outputs a low level signal, and the watchdog chip 103 outputs a low level signal, both will output a high level signal through the level conversion module 104, and the second controllable switch Q2 will be in the on state, thereby triggering the three-terminal fuse M to melt, so that the purpose of protecting the rechargeable battery 100 can be achieved.

[0039] It should be noted that, when the analog chip 101 monitors the operating state of the rechargeable battery 100, the analog chip 101 will monitor the operating temperature and operating voltage of the rechargeable battery 100 in real time. Once the analog chip 101 detects that the operating temperature of the rechargeable battery 100 exceeds the first set value, and / or the analog chip 101 detects that the operating voltage of the rechargeable battery 100 exceeds the second set value, and / or the analog chip 101 cannot detect the operating temperature of the rechargeable battery 100, and / or the analog chip 101 cannot detect the operating voltage of the rechargeable battery 100, the analog chip 101 will determine that the operating state of the rechargeable battery 100 is abnormal.

[0040] Specifically, in practical applications, the rechargeable battery can be set to a lithium iron phosphate battery, a nickel cadmium battery, a nickel metal hydride battery, etc. In addition, the analog chip can be set to an MCU (Microcontroller Unit), an FPGA (Field Programmable Gate Array) or a CPU (Central Processing Unit), and the analog chip can be set to an AFE (Active Front End) chip.

[0041] In addition, in the prior art, sometimes multiple redundant control chips 102 are set in the circuit, the purpose of which is that when one of the control chips 102 fails, the other control chips 102 can trigger the three-terminal fuse M to melt to ensure the safe operation of the rechargeable battery 100. However, the setting cost of the control chip 102 is high, and when the rechargeable battery 100 is protected by this existing method, a large amount of cost investment is required. Compared with this method to protect the rechargeable battery 100, the protection device provided by the present application can greatly reduce the cost investment when protecting the rechargeable battery 100.

[0042] In the rechargeable battery protection device provided by the present application, when the control chip is operating normally, if the analog chip detects that the operating state of the rechargeable battery is abnormal, the control chip will output a control signal to the first controllable switch to blow the three-terminal fuse, thereby achieving the purpose of protecting the rechargeable battery. When the control chip fails, if the analog chip detects that the operating state of the rechargeable battery is abnormal, the fault output pin of the analog chip will output a low-level signal, and the watchdog chip will also output a low-level signal because it detects that the control chip fails. In this case, the level conversion module will output a high-level signal and trigger the second controllable switch to blow the three-terminal fuse, thereby achieving the purpose of protecting the rechargeable battery. Obviously, the rechargeable battery protection device provided by the present application can further improve the safety of the rechargeable battery during operation.

[0043] Based on the above embodiments, this embodiment further illustrates and optimizes the technical solution. As a preferred implementation, the level conversion module 104 is specifically a NAND gate circuit.

[0044] Specifically, in practical applications, the level conversion module 104 can be set as a NAND gate circuit. Because the control logic of the NAND gate circuit is consistent with the control logic of the level conversion module 104, and the NAND gate circuit has a low cost and a simple structure, when the level conversion module 104 is set as a NAND gate circuit, the cost investment and construction difficulty of building the protection device can be further reduced.

[0045] Obviously, the technical solution provided by this embodiment can not only reduce the structural complexity of the protection device, but also reduce the design cost of the protection device.

[0046] Based on the above embodiments, this embodiment further illustrates and optimizes the technical solution. As a preferred implementation, the first controllable switch Q1 and the second controllable switch Q2 are respectively the first NMOS transistor and the second NMOS transistor;

[0047] Correspondingly, the drain of the first NMOS tube is the first end of the first controllable switch Q1, the source of the first NMOS tube is the second end of the first controllable switch Q1, the gate of the first NMOS tube is the control end of the first controllable switch Q1, the drain of the second NMOS tube is the first end of the second controllable switch Q2, the source of the second NMOS tube is the second end of the second controllable switch Q2, and the gate of the second NMOS tube is the control end of the second controllable switch Q2.

[0048] Because the manufacturing cost of NMOS (N-Metal-Oxide-Semiconductor) tubes is lower, and in the protection device provided in the present application, the property characteristics of the NMOS tubes are more consistent with the logical actions of the first controllable switch Q1 and the second controllable switch Q2, and there is no need to set other electronic components in the circuit. Therefore, in practical applications, the first controllable switch Q1 and the second controllable switch Q2 can both be set as NMOS tubes.

[0049] Obviously, the technical solution provided by this embodiment can relatively reduce the structural complexity and cost investment of the protection device.

[0050] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. Figure 2 , Figure 2 This is a structural diagram of another rechargeable battery protection device provided by an embodiment of the utility model. As a preferred embodiment, the protection device further includes: a DC / DC conversion circuit 105 for supplying power to the control chip 102;

[0051] The input end of the DC / DC conversion circuit 105 is connected to the second end of the three-terminal fuse M, and the output end of the DC / DC conversion circuit 105 is connected to the control chip 102 .

[0052] In this embodiment, in order to ensure the stability and reliability of the control chip 102 during operation, a DC / DC (direct current / direct current) conversion circuit 105 for powering the control chip 102 may be provided in the protection device. The DC / DC conversion circuit 105 may convert the output voltage of the circuit where the rechargeable battery 100 is located into the power supply voltage required by the control chip 102 to provide an energy source for the control chip 102.

[0053] Because the output voltage of the circuit where the rechargeable battery 100 is located is higher than the power supply voltage required by the control chip 102, in practical applications, the DC / DC conversion circuit 105 can also be set as a BUCK (step-down) circuit to provide the required power supply voltage for the control chip 102. Since the DC / DC conversion circuit and the BUCK circuit are circuit structures well known to those skilled in the art, they are not described in detail here.

[0054] Obviously, the technical solution provided by this embodiment can further ensure the stability and reliability of the control chip during operation.

[0055] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. Figure 2 , Figure 2This is a structural diagram of another rechargeable battery protection device provided by an embodiment of the utility model. As a preferred implementation, the protection device further includes: a first resistor R1, a third controllable switch Q3 and a fourth controllable switch Q4;

[0056] Wherein, a first end of the first resistor R1 is connected to the negative electrode of the rechargeable battery, a second end of the first resistor R1 is connected to the second end of the third controllable switch Q3, and a first end of the third controllable switch Q3 is connected to a first end of the fourth controllable switch Q4;

[0057] Correspondingly, the control end of the third controllable switch Q3 and the control end of the fourth controllable switch Q4 are both connected to the control chip; the second end of the fourth controllable switch Q4 is correspondingly replaced by the negative output end P- of the entire circuit.

[0058] It is understandable that the rechargeable battery 100 is usually used to charge a load in practical applications. Therefore, in the protection device provided in this embodiment, the charge and discharge process of the rechargeable battery 100 can also be intervened by a controllable switch. Figure 2 In the protection device shown, the third controllable switch Q3 can be called a discharge tube, through which the rechargeable battery 100 can be discharged. The fourth controllable switch Q4 can be called a charging tube, through which the rechargeable battery 100 can be charged. The first resistor R1 is used to detect current.

[0059] In practical applications, the third controllable switch Q3 and the fourth controllable switch Q4 can be set as a third NMOS tube and a fourth NMOS tube, respectively. The gate of the third NMOS tube is the control end of the third controllable switch Q3, the drain of the third NMOS tube is the first end of the third controllable switch Q3, and the source of the third NMOS tube is the second end of the third controllable switch Q3. The gate of the fourth NMOS tube is the control end of the fourth controllable switch Q4, the drain of the fourth NMOS tube is the first end of the fourth controllable switch Q4, and the source of the fourth NMOS tube is the second end of the fourth controllable switch Q4.

[0060] It should be noted that, in actual application, if the analog chip 101 detects that the operating state of the rechargeable battery 100 is abnormal, the third controllable switch Q3 and the fourth controllable switch Q4 will be stuck. At this time, if the operating state of the control chip 102 is normal, the control chip 102 will output a PWM wave to trigger the first controllable switch Q1 to turn on and blow the three-terminal fuse M, so that the purpose of protecting the rechargeable battery 100 can be achieved. At this time, if the control chip 102 fails, the fault output pin NFAULT of the analog chip 101 will output a low-level signal, and the watchdog chip 103 will output a low-level signal because it detects that the control chip 102 fails. In this case, these two low-level signals will output a high-level signal through the level conversion module 104, and at this time the second controllable switch Q2 will be in a conducting state, thereby triggering the three-terminal fuse M to blow, so that the purpose of protecting the rechargeable battery 100 can be achieved.

[0061] Obviously, through the technical solution provided in this embodiment, the charging and discharging process of the rechargeable battery can be intervened, which can further broaden the application scope of the protection device provided in this application.

[0062] As a preferred implementation, the protection device further includes: a second resistor R2 and a fifth controllable switch Q5;

[0063] Among them, the first end of the second resistor R2 is connected to the second end of the first resistor R1, the second end of the second resistor R2 is connected to the second end of the fifth controllable switch Q5, the first end of the fifth controllable switch Q5 is connected to the first end of the fourth controllable switch Q4, and the control end of the fourth controllable switch Q4 is connected to the control chip 102.

[0064] It is understandable that if the charging voltage of the load is too large at the beginning of charging, the load is easily damaged. In order to avoid this situation, in this embodiment, a fifth controllable switch Q5 can also be set in the protection device. Among them, the fifth controllable switch Q5 can be regarded as a pre-charging tube, and the charging voltage of the load can be controlled by the fifth controllable switch Q5, so as to achieve the purpose of limiting the charging current.

[0065] Specifically, the fifth controllable switch Q5 can be set as a fifth NMOS tube, wherein the gate of the fifth NMOS tube is the control end of the fifth controllable switch Q5, the drain of the fifth NMOS tube is the first end of the fifth controllable switch Q5, and the source of the fifth NMOS tube is the second end of the fifth controllable switch Q5.

[0066] Obviously, the technical solution provided in this embodiment can ensure the safety and reliability of the load during the charging process.

[0067] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. Figure 3 , Figure 3 A structural diagram of another rechargeable battery protection device provided by an embodiment of the utility model. As a preferred embodiment, the protection device further includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1 and a second capacitor C2;

[0068] The second end of the third resistor R3 is respectively connected to the first end of the first capacitor C1, the first end of the fourth resistor R4 and the control end of the first controllable switch Q1, and the second end of the first capacitor C1 and the second end of the fourth resistor R4 are both connected to the second end of the first controllable switch Q1; the control end of the second controllable switch Q2 is respectively connected to the first end of the fifth resistor R5, the first end of the second capacitor C2 and the first end of the sixth resistor R6, and the second end of the second controllable switch Q2, the second end of the fifth resistor R5 and the second end of the second capacitor C2 are all grounded;

[0069] Correspondingly, a first end of the third resistor R3 is connected to the control chip 102 , and a second end of the sixth resistor R6 is connected to the output end of the level conversion module 104 .

[0070] exist Figure 3 In the circuit diagram shown, NAND represents a NAND gate circuit, nfault represents a level signal output by the fault output pin NFAULT of the analog chip 101, and w represents a level signal output by the watchdog chip 103. PWM represents a PWM wave output by the control chip 102.

[0071] In practical applications, in order to ensure the stability and reliability of the first controllable switch Q1 and the second controllable switch Q2 during operation, electronic components may be added between the control terminal and the second terminal of the first controllable switch Q1 to prevent the first controllable switch Q1 from being broken down when a large current flows through the first controllable switch Q1. That is, the purpose of adding the third resistor R3, the fourth resistor R4 and the first capacitor C1 around the first controllable switch Q1 is to buffer the large current flowing through the first controllable switch Q1, thereby achieving the purpose of protecting the first controllable switch Q1.

[0072] Similarly, the purpose of adding the fifth resistor R5, the sixth resistor R6 and the second capacitor C2 around the second controllable switch Q2 is also to buffer the large current flowing through the second controllable switch Q2, so as to protect the second controllable switch Q2.

[0073] As a preferred implementation, the protection device further includes: a seventh resistor R7 and a third capacitor C3;

[0074] The first end of the seventh resistor R7 is connected to the first end of the third capacitor C3, the second end of the seventh resistor R7 is grounded, and the second end of the third capacitor C3 is connected to the first end of the third resistor R3;

[0075] Correspondingly, a first end of the seventh resistor R7 is connected to the control chip 102 .

[0076] In this embodiment, the charging and discharging state of the third capacitor C3 can also be controlled by using PWM of a specific frequency, so as to achieve the purpose of controlling the on-off state of the first controllable switch Q1 and prevent the first controllable switch Q1 from being triggered by mistake.

[0077] Obviously, through the technical solution provided in this embodiment, the safety and reliability of the first controllable switch and the second controllable switch during operation can be further guaranteed.

[0078] Correspondingly, an embodiment of the utility model further provides a battery management system, including a protection device for a rechargeable battery as disclosed above.

[0079] A battery management system provided by an embodiment of the utility model has the beneficial effects of the aforementioned rechargeable battery protection device.

[0080] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A protection device for a rechargeable battery, characterized in that: include: An analog chip for monitoring the operating state of a rechargeable battery, a control chip communicatively connected to the analog chip, a watchdog chip for monitoring the operating state of the control chip, a level conversion module for outputting a high level signal only when two low level signals are received, a three-terminal fuse, a first controllable switch, and a second controllable switch; Wherein, the first end of the three-terminal fuse is connected to the positive electrode of the rechargeable battery, the third end of the three-terminal fuse is respectively connected to the first end of the first controllable switch and the first end of the second controllable switch, the second end of the first controllable switch and the second end of the second controllable switch are both connected to the negative electrode of the rechargeable battery, the control end of the first controllable switch is connected to the control chip, the control end of the second controllable switch is connected to the output end of the level conversion module, and the two input ends of the level conversion module are respectively connected to the fault output pin of the analog chip and the output end of the watchdog chip; Correspondingly, the second end of the three-terminal fuse is the positive output end of the entire circuit, and the negative electrode of the rechargeable battery is the negative output end of the entire circuit.

2. A protection device for a rechargeable battery according to claim 1, characterized in that: The level conversion module is specifically a NAND gate circuit.

3. A protection device for a rechargeable battery according to claim 1, characterized in that: The first controllable switch and the second controllable switch are respectively a first NMOS tube and a second NMOS tube; Correspondingly, the drain of the first NMOS tube is the first end of the first controllable switch, the source of the first NMOS tube is the second end of the first controllable switch, the gate of the first NMOS tube is the control end of the first controllable switch, the drain of the second NMOS tube is the first end of the second controllable switch, the source of the second NMOS tube is the second end of the second controllable switch, and the gate of the second NMOS tube is the control end of the second controllable switch.

4. A protection device for a rechargeable battery according to claim 1, characterized in that: Also includes: A DC / DC conversion circuit for supplying power to the control chip; Wherein, the input end of the DC / DC conversion circuit is connected to the second end of the three-terminal fuse, and the output end of the DC / DC conversion circuit is connected to the control chip.

5. A protection device for a rechargeable battery according to claim 4, characterized in that: The DC / DC conversion circuit is specifically a BUCK circuit.

6. A protection device for a rechargeable battery according to claim 1, characterized in that: Also includes: a first resistor, a third controllable switch and a fourth controllable switch; Wherein, the first end of the first resistor is connected to the negative electrode of the rechargeable battery, the second end of the first resistor is connected to the second end of the third controllable switch, and the first end of the third controllable switch is connected to the first end of the fourth controllable switch; Correspondingly, the control end of the third controllable switch and the control end of the fourth controllable switch are both connected to the control chip; and the second end of the fourth controllable switch is correspondingly replaced by the negative output end of the entire circuit.

7. A protection device for a rechargeable battery according to claim 6, characterized in that: Also includes: a second resistor and a fifth controllable switch; Among them, the first end of the second resistor is connected to the second end of the first resistor, the second end of the second resistor is connected to the second end of the fifth controllable switch, the first end of the fifth controllable switch is connected to the first end of the fourth controllable switch, and the control end of the fourth controllable switch is connected to the control chip.

8. The protection device for a rechargeable battery according to claim 1, characterized in that: Also includes: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, and a second capacitor; The second end of the third resistor is respectively connected to the first end of the first capacitor, the first end of the fourth resistor and the control end of the first controllable switch, and the second end of the first capacitor and the second end of the fourth resistor are both connected to the second end of the first controllable switch; the control end of the second controllable switch is respectively connected to the first end of the fifth resistor, the first end of the second capacitor and the first end of the sixth resistor, and the second end of the second controllable switch, the second end of the fifth resistor and the second end of the second capacitor are all grounded; Correspondingly, a first end of the third resistor is connected to the control chip, and a second end of the sixth resistor is connected to the output end of the level conversion module.

9. A protection device for a rechargeable battery according to claim 8, characterized in that: Also includes: a seventh resistor and a third capacitor; Wherein, the first end of the seventh resistor is connected to the first end of the third capacitor, the second end of the seventh resistor is grounded, and the second end of the third capacitor is connected to the first end of the third resistor; Correspondingly, the first end of the seventh resistor is connected to the control chip.

10. A battery management system, characterized in that: A protection device for a rechargeable battery comprising the device described in any one of claims 1 to 9.

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