A lithium ion battery protection circuit

Abstract

The present application relates to a lithium-ion battery protection circuit, which is used in a power storage device. The circuit includes a main control chip, a first protection circuit, and a second protection circuit. The first protection circuit and the second protection circuit are both connected to the power supply circuit of the power storage device. The main control chip is provided with a first control terminal and a second control terminal. The first control terminal is connected to the first protection circuit, and the second control terminal is connected to the second protection circuit. The main control chip controls the on-off of the power supply circuit of the power storage device by controlling the on-off of the first protection circuit and the protection circuit. Its beneficial effect is that when the lithium-ion battery exceeds the safe voltage range and the safe temperature range during use, the circuit automatically cuts off the battery power supply circuit, and no longer charges or discharges the lithium-ion battery, thereby ensuring the safety of the user.

Description

Technical Field

[0001] The present application relates to the technical field of battery management systems, and in particular to a lithium-ion battery protection circuit. Background Art

[0002] At present, with the increase in the application fields of lithium-ion batteries, they are widely used in smart phones, mobile power banks, power tools, and vacuum cleaners. However, due to their relatively high energy and high storage energy density, if lithium-ion batteries are over-charged and discharged during the charging and discharging process, the lithium-ion battery body will generate a lot of heat, which will lead to safety problems such as explosion and fire of lithium-ion batteries. The safety of lithium-ion batteries is a key concern for consumers. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a lithium-ion battery protection circuit, which is applied to a power storage device. The circuit includes a main control chip, a first protection circuit, and a second protection circuit.

[0004] The first protection circuit and the second protection circuit are both connected to the power supply circuit of the power storage device; the main control chip is provided with a first control end and a second control end, the first control end is connected to the first protection circuit, and the second control end is connected to the second protection circuit;

[0005] The main control chip controls the on and off of the power supply circuit of the power storage device by controlling the first protection circuit and the on and off of the protection circuit.

[0006] Optionally, the first protection circuit includes a first trigger circuit and a switch circuit.

[0007] The switch circuit is connected to the power supply loop, and the switch circuit is connected to the first control end through a first trigger circuit.

[0008] Optionally, the switch circuit includes a first MOS tube, a first resistor, and a second resistor.

[0009] The gate of the first MOS tube is connected to the first trigger circuit through a first resistor, and the source and drain are respectively connected to the two ends of the power supply loop; the second resistor is respectively connected between the gate and source of the first MOS tube.

[0010] Optionally, the second protection circuit includes a second trigger circuit and a fuse circuit.

[0011] The fuse circuit is connected to the power supply circuit, and the fuse circuit is connected to the second control end through a second trigger circuit.

[0012] Optionally, the fusing circuit includes a fuse and a third resistor.

[0013] The control end of the fuse is connected to the second trigger circuit through a third resistor, and the two connection ends of the fuse are respectively connected to the power supply circuit.

[0014] Optionally, the first trigger circuit includes a second MOS tube, a fourth resistor, a fifth resistor, a first capacitor, and a first diode;

[0015] The gate of the second MOS tube is connected to the first control end through a fourth resistor, the drain is connected to the switch circuit through a first diode, and the source is grounded; the fifth resistor and the first capacitor are both connected between the gate of the second MOS tube and the power ground.

[0016] Optionally, it further includes a power supply circuit, wherein the power supply circuit includes a power supply chip, a sixth resistor, and a second capacitor.

[0017] The power input end of the power chip is connected to the power supply circuit through a sixth resistor, and the power output end of the power chip is connected to the power supply end of the main control chip through a filter circuit.

[0018] Optionally, the filtering circuit includes a seventh resistor and a third capacitor, the power output terminal of the power chip is connected to the power supply through the seventh resistor, and the third capacitor is connected between the power supply terminal and the power ground.

[0019] Optionally, it also includes a temperature detection circuit, which includes a temperature sensor connected to the temperature detection end of the main control chip and an eighth resistor, the other end of the eighth resistor is connected to the power output end of the power chip, and the other end of the temperature sensor is grounded.

[0020] Optionally, the main control chip is further provided with at least one voltage monitoring terminal, and the voltage monitoring terminal is connected to the battery of the power storage device through a ninth resistor.

[0021] A lithium-ion battery protection circuit of the present application has the beneficial effect that: the present application performs multi-faceted detection of the battery through temperature detection and voltage monitoring. At the same time, a first protection circuit and a second protection circuit are used. When the lithium-ion battery exceeds a safe voltage range and a safe temperature range during use, the circuit automatically cuts off the battery power supply circuit and no longer charges or discharges the lithium-ion battery, thereby ensuring user safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a circuit schematic diagram of the communication activation circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer definition of the protection scope of the present application.

[0024] In such Figure 1 In the illustrated embodiment, the present application provides a lithium-ion battery protection circuit, which is applied to a power storage device. The circuit includes a main control chip U1, a first protection circuit, and a second protection circuit. The first protection circuit and the second protection circuit are both connected to the power supply circuit of the power storage device; the main control chip U1 is provided with a first control terminal U1_CO and a second control terminal U1_FUSE. The first control terminal U1_CO is connected to the first protection circuit, and the second control terminal U1_FUSE is connected to the second protection circuit; the main control chip U1 controls the on-off of the power supply circuit of the power storage device by controlling the on-off of the first protection circuit and the protection circuit. The present application performs multi-faceted detection of the battery through temperature detection and voltage monitoring. At the same time, the first protection circuit and the second protection circuit are used. When the lithium-ion battery exceeds the safe voltage range and the safe temperature range during use, the circuit automatically cuts off the battery power supply circuit, and no longer charges or discharges the lithium-ion battery, thereby ensuring the safety of the user. Among them, the power storage device can be a battery or a battery pack. The main control chip can be a chip with the model number ML62Q1345.

[0025] In some embodiments, the first protection circuit includes a first trigger circuit 3 and a switch circuit 1. The switch circuit 1 is connected to the power supply circuit, and the switch circuit 1 is connected to the first control terminal U1_CO through the first trigger circuit 3. Specifically, the switch circuit 1 includes a first MOS tube Q1, a first resistor R1, and a second resistor R2. The gate of the first MOS tube Q1 is connected to the first trigger circuit 3 through the first resistor R1, and the source and drain are respectively connected to the two ends of the power supply circuit B+ - P+; the second resistor R2 is respectively connected between the gate and the source of the first MOS tube Q1. In this embodiment, the switch circuit 1 receives the signal of the first control terminal U1_CO through the first trigger circuit 3 to control the on and off of the power supply circuit B+ - P+ of the power storage device; the first resistor R1 and the second resistor R2 are used for voltage division. The first trigger circuit 3 includes a second MOS tube Q2, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, and a first diode D1; the gate of the second MOS tube Q2 is connected to the first control terminal U1_CO through the fourth resistor R4, the drain is connected to the switch circuit 1 through the first diode D1, and the source is grounded; the fifth resistor R5 and the first capacitor C1 are both connected between the gate of the second MOS tube Q2 and the power ground. Among them, the fourth resistor R4 and the fifth resistor R5 are used for voltage division, the first capacitor C1 is used for filtering, and the first diode D1 is used for circuit protection; when the cell voltage of the power storage device is higher than the cell voltage protection voltage threshold or the cell temperature protection voltage threshold, the first control terminal U1_CO outputs a high level, passes through the first trigger circuit 3 to the first MOS tube Q1, the second MOS tube Q2 is turned on, and the first MOS tube Q1 is turned off. When the cell voltage of the power storage device is lower than the cell voltage protection voltage threshold or the cell temperature protection voltage threshold, the low level of the first control terminal U1_CO controls the gate of the first MOS tube Q1 to turn on through its first trigger circuit 3, the battery pack is charged normally, and normal charging operation protection is achieved.

[0026] In some embodiments, the second protection circuit includes a second trigger circuit and a fuse circuit 2. The fuse circuit 2 is connected to the power supply circuit B+ - P+. The fuse circuit 2 is connected to the second control terminal U1_FUSE through the second trigger circuit. Specifically, the fuse circuit 2 includes a fuse FUSE and a third resistor R3. The control terminal of the fuse FUSE is connected to the second trigger circuit through the third resistor R3, and the two connection terminals of the fuse FUSE are respectively connected to the power supply circuit B+ - P+. In this embodiment, the fuse circuit 2 receives the signal of the second control terminal U1_FUSE through the second trigger circuit to control the power supply circuit B+ - P+ of the power storage device to be fused; the third resistor R3 is used for voltage division. The circuit structure of the second trigger circuit is consistent with that of the first trigger circuit, and its specific function can refer to the first trigger circuit. The fuse FUSE has three terminals: a control terminal and two connection terminals. The two connection terminals are respectively connected to the two ends of the circuit, and the control terminal is connected to the second trigger circuit. When the cell voltage of the power storage device is working normally, the second control terminal U1_FUSE outputs a low level, passes through the MOS tube to the fuse FUSE, the MOS tube is cut off, the control end of the fuse FUSE is high level, and the charging current charges the battery pack normally through the fuse FUSE. When the cell voltage is higher than the cell safety voltage range or the cell temperature is higher than the safety temperature range, the second control terminal U1_FUSE outputs a high level, the MOS tube is turned on, and the control end of the fuse FUSE is pulled low, so that the fuse FUSE element is blown, and the battery pack is disconnected from the charger and the load, thereby realizing self-fusing safety protection. The fuse FUSE can be a fuse with model WPF05A7R.

[0027] In some embodiments, a power supply circuit 4 is also included, and the power supply circuit 4 includes a power supply chip U2, a sixth resistor R6, and a second capacitor C2. The power input terminal of the power supply chip U2 is connected to the power supply circuit B+-P+ through the sixth resistor R6, and the power output terminal VCC of the power supply chip U2 is connected to the power supply terminal of the main control chip U1 through the filtering circuit. In this embodiment, the power supply circuit 4 converts the power supply of the power supply circuit B+-P+ into a power supply suitable for the working voltage of the main control chip U1, which is used to power the main control chip U1. The sixth resistor R6 is used for voltage division and the second capacitor C2 is used for filtering. Among them, the power supply chip can be a power supply chip with a model of TLV70433.

[0028] In some embodiments, the filter circuit includes a seventh resistor R7 and a third capacitor C3. The power output terminal VCC of the power chip U2 is connected to the power supply through the seventh resistor R7, and the third capacitor C3 is connected between the power supply terminal and the power ground. The seventh resistor R7 is used for voltage division, and the third capacitor C3 is used for filtering; the filter circuit protects the circuit.

[0029] In some embodiments, a temperature detection circuit 5 is also included. The temperature detection circuit 5 includes a temperature sensor TH1 and an eighth resistor R8 connected to the temperature detection end of the main control chip U1. The other end of the eighth resistor R8 is connected to the power output end VCC of the power chip U2, and the other end of the temperature sensor TH1 is grounded. The temperature sensor can be a 10K NTC temperature sensor. The main control chip U1 is also provided with at least one voltage monitoring end, and the voltage monitoring end is connected to the battery of the power storage device through the ninth resistor R9; the main control chip can be provided with multiple voltage monitoring ends connected to multiple batteries for monitoring the voltages of multiple batteries. The present application performs multi-faceted detection of the battery through temperature detection and voltage monitoring. At the same time, the first protection circuit and the second protection circuit are used. When the lithium-ion battery exceeds the safe voltage range and the safe temperature range during use, the circuit automatically cuts off the battery power supply circuit, and no longer charges or discharges the lithium-ion battery, thereby ensuring the safety of the user.

[0030] The implementation modes of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present application.

Claims

1. A lithium-ion battery protection circuit, characterized in that: Applied in a power storage device, the circuit includes a main control chip, a first protection circuit, and a second protection circuit. The first protection circuit and the second protection circuit are both connected to the power supply circuit of the power storage device; the main control chip is provided with a first control end and a second control end, the first control end is connected to the first protection circuit, and the second control end is connected to the second protection circuit; The main control chip controls the on / off of the power supply circuit of the power storage device by controlling the first protection circuit and the on / off of the protection circuit; The first protection circuit includes a first trigger circuit and a switch circuit. The switch circuit is connected to the power supply circuit. The switch circuit is connected to the first control terminal through the first trigger circuit. The switch circuit includes a first MOS tube, a first resistor, and a second resistor. The gate of the first MOS tube is connected to the first trigger circuit through a first resistor, and the source and drain are respectively connected to the two ends of the power supply loop; the second resistor is respectively connected between the gate and the source of the first MOS tube; The second protection circuit includes a second trigger circuit and a fuse circuit. The fuse circuit is connected to the power supply circuit and is connected to the second control terminal through the second trigger circuit. The fuse circuit includes a fuse and a third resistor. The control end of the fuse is connected to the second trigger circuit through a third resistor, and the two connection ends of the fuse are respectively connected to the power supply circuit; the first trigger circuit includes a second MOS tube, a fourth resistor, a fifth resistor, a first capacitor, and a first diode; The gate of the second MOS tube is connected to the first control terminal through a fourth resistor, the drain is connected to the switch circuit through a first diode, and the source is grounded; the fifth resistor and the first capacitor are both connected between the gate of the second MOS tube and the power ground; The main control chip is further provided with at least one voltage monitoring terminal, and the voltage monitoring terminal is connected to the battery of the power storage device through a ninth resistor.

2. A lithium-ion battery protection circuit according to claim 1, characterized in that: It also includes a power supply circuit, which includes a power supply chip, a sixth resistor, and a second capacitor. The power input end of the power chip is connected to the power supply circuit through a sixth resistor, and the power output end of the power chip is connected to the power supply end of the main control chip through a filter circuit.

3. A lithium-ion battery protection circuit according to claim 2, characterized in that: The filtering circuit includes a seventh resistor and a third capacitor. The power output terminal of the power chip is connected to the power supply through the seventh resistor, and the third capacitor is connected between the power supply terminal and the power ground.

4. A lithium-ion battery protection circuit according to claim 2, characterized in that: It also includes a temperature detection circuit, which includes a temperature sensor connected to the temperature detection end of the main control chip and an eighth resistor, the other end of the eighth resistor is connected to the power output end of the power chip, and the other end of the temperature sensor is grounded.

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