Multi-battery series output battery pack protection circuit

Abstract

The utility model relates to the technical field of battery power supply circuits, in particular to a multi-battery series output battery pack protection circuit, which comprises a power supply module, a driving switch module, a control module, a temperature detection module, a load and charging detection module and a battery voltage detection module, the power supply module comprises a battery pack formed by combining and connecting a plurality of single batteries and a power supply management chip connected with the output end of the battery pack, the temperature detection module is used for detecting the temperature of a protection circuit and a battery body, and the load and charging detection module is used for detecting a load and the battery pack. The battery voltage detection module detects a single battery and a whole battery pack, the input end of the driving switch module is connected with the output end of the power management chip, the output end of the driving switch module is connected with a load, and the control module is connected with the load and the control end of the charging detection module and the control end of the driving switch module. According to the utility model, control and safety detection of the battery pack can be realized.

Description

Technical Field

[0001] This utility model relates to the field of battery power circuit technology, specifically to a multi-cell series output battery pack protection circuit. Background Technology

[0002] In recent years, with the development of battery material technology, battery capacity has been significantly increased, and its application range has expanded from low-power electronic devices to high-power electrical devices, such as power tools. This allows power tools using high-rate batteries to be used anytime, anywhere, freeing them from the constraints of cables. To improve utilization, these batteries are typically rechargeable, such as nickel-cadmium (NiCd) batteries, nickel-metal hydride (NiMH) batteries, and lithium-ion (L-ion) batteries.

[0003] To increase capacity, existing battery packs typically incorporate multiple batteries. An integrated microprocessor (MCU) is used to collect the output voltage and current of the entire battery pack and determine if they meet requirements, thereby protecting the entire battery pack from discharge. However, due to the high integration of the MCU, when used solely for over-discharge or over-current protection, the utilization rate of functions other than over-discharge and over-current detection is low. Furthermore, it cannot accurately and completely detect the charging status, which can easily lead to battery damage or failure to promptly identify individual battery malfunctions. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a multi-battery series output battery pack protection circuit.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a multi-cell series output battery pack protection circuit, comprising a power supply module, a drive switch module, a control module, a temperature detection module, a load and charging detection module, and a battery voltage detection module. The power supply module includes a battery pack composed of multiple single cells connected together and a power management chip connected to the output terminal of the battery pack. The power management chip supplies power to the control module and the temperature detection module. The temperature detection module detects the temperature of the protection circuit and the battery body, with its detection terminals respectively located at the protection circuit board and the battery body, and its signal output terminal connected to the input terminal of the control module. The detection terminals of the load and charging detection module are respectively connected to the power supply terminal of the load and the charging port of the battery pack, and its signal terminal is connected to the input terminal of the control module. The battery voltage detection module is connected to detect individual cells and the entire battery pack, and its signal terminal is connected to the input terminal of the control module. The input terminal of the drive switch module is connected to the output terminal of the power management chip, and the output terminal of the drive switch module is connected to the load. The control module is connected to the control terminals of the load and charging detection module and the drive switch module.

[0006] In some embodiments, the control module is an MCU processor.

[0007] In some embodiments, the drive switch module includes a transistor 1, a transistor 2, and a voltage regulator. The base of transistor 1 is connected to the output terminal of the control module, the emitter of transistor 1 is grounded, the collector of transistor 1 is connected to the base of transistor 2, the emitter of transistor 2 is connected to the power output terminal of the battery pack, the collector of transistor 2 is connected to the input terminal of the voltage regulator, and the output terminal of the voltage regulator is connected to the load.

[0008] In some embodiments, the first transistor is an NPN transistor, the second transistor is a PNP transistor, and a resistor is connected in series between the emitter and base of the second transistor.

[0009] In some embodiments, the temperature detection module includes a temperature sensor one and a temperature sensor two, with the detection ends of temperature sensor one and temperature sensor two respectively located at the protection circuit board and the battery body, and the signal ends of temperature sensor one and temperature sensor two respectively connected to the input end of the control module.

[0010] In some embodiments, the load and charging detection module includes a load detection circuit and a charging detection circuit. The detection terminal of the load detection circuit is connected to the power supply terminal on the load, and the output terminal of the load detection circuit is connected to the input terminal of the control module. The input terminal of the charging detection circuit is connected to an external charger, the output terminal is connected to the power supply terminal of the battery pack, and the control terminal is connected to the output terminal of the control module.

[0011] In some embodiments, the load detection circuit includes a detection resistor, a filter capacitor, a transistor, and a diode. The detection resistor is connected in series between the power supply terminal of the load and the input terminal of the control module. One end of the filter capacitor is connected to the detection resistor and the control module, and the other end of the filter capacitor is grounded. The power output terminal of the power management chip is connected to the negative terminal of the diode. The positive terminal of the diode is connected to the collector of the transistor and the connection point of the detection resistor and the filter capacitor, respectively. The base of the transistor is connected to the output terminal of the control module, and the emitter of the transistor is grounded.

[0012] In some embodiments, the charging detection circuit includes transistors four, five, six, and seven, MOSFET one and MOSFET two.

[0013] The emitter of transistor 4 is connected to the positive terminal of the external charger, the collector of transistor 4 is connected to the base of transistor 5, the emitter of transistor 5 is grounded, and the collector of transistor 5 is connected to the input terminal of the control module.

[0014] The bases of transistors six and seven are connected to one output terminal of the control module, and the emitters of both transistors six and seven are connected to the power output terminal of the power management chip. The collector of transistor six is ​​connected to the gate of MOSFET one, and the collector of transistor seven is connected to the gate of MOSFET two.

[0015] The positive terminal of the external charger is connected to the positive terminal of the battery pack, the negative terminal of the external charger is connected to the source of MOSFET 1, the drain of MOSFET 1 is connected to the source of MOSFET 2, and the drain of MOSFET 2 is connected to the negative terminal of the battery pack.

[0016] In some embodiments, transistor five is an NPN transistor, and transistors four, six, and seven are all PNP transistors. A resistor is connected in series between the base and emitter of transistors four, six, and seven.

[0017] In some embodiments, the battery voltage detection module consists of N detection units, the total number of detection units being the number of all single batteries in the power module plus one. One detection unit is connected to the power supply terminal of the battery pack, and the remaining detection units are connected to each single battery in the power module in a one-to-one correspondence. The detection unit is a MOSFET, the gate of which is connected to the output terminal of the control module, the drain of which is connected to the power supply terminal of the corresponding battery, and the source of which is connected to the input terminal of the control module.

[0018] Compared with the prior art, the beneficial effects of this utility model are: it can determine whether the battery pack and individual batteries are in an abnormal state, and provide protection for the battery pack based on the determination result, so as to ensure the normal operation of the battery pack.

[0019] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0020] Figure 1 This is a module diagram of the present utility model;

[0021] Figure 2 This is the circuit schematic diagram of this utility model;

[0022] Figure 3 This is a schematic diagram of the power module circuit of this utility model;

[0023] Figure 4 This is the circuit schematic diagram of the control module of this utility model;

[0024] Figure 5 This is a circuit schematic diagram of the drive switch module and temperature detection module of this utility model;

[0025] Figure 6 This is a circuit schematic diagram of the load and charging detection module of this utility model;

[0026] Figure 7 This is a circuit diagram of the battery voltage detection module of this utility model.

[0027] In the diagram: 1. Power supply module; 2. Drive switch module; 3. Control module; 4. Temperature detection module; 5. Load and charging detection module; 6. Battery voltage detection module; 7. Load detection circuit; 8. Charging detection circuit. Detailed Implementation

[0028] 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.

[0029] Please see Figure 1-2This utility model provides a technical solution: a multi-cell series output battery pack protection circuit, including a power supply module, a drive switch module, a control module, a temperature detection module, a load and charging detection module, and a battery voltage detection module. The power supply module includes a battery pack composed of multiple single cells connected together and a power management chip connected to the output terminal of the battery pack. The power management chip supplies power to the control module and the temperature detection module. The temperature detection module is used to detect the temperature of the protection circuit and the battery body. Its detection terminals are respectively set at the protection circuit board and the battery body, and its signal output terminal is connected to the input terminal of the control module. The detection terminals of the load and charging detection module are respectively connected to the power supply terminal of the load and the charging port of the battery pack, and its signal terminal is connected to the input terminal of the control module. The battery voltage detection module is connected to detect individual cells and the entire battery pack. The signal terminal of the battery voltage detection module is connected to the input terminal of the control module. The input terminal of the drive switch module is connected to the output terminal of the power management chip, and the output terminal of the drive switch module is connected to the load. The control module is connected to the control terminals of the load and charging detection module and the drive switch module.

[0030] like Figure 3 As shown, in the actual application, the power module is equipped with 5 single batteries (B1-B5), and the 5 single batteries are connected in series to form a battery pack (BAT). The power output of the battery pack is stepped down to 12V after passing through the voltage regulator U1 to provide driving power for the load MOS. Then, it is stepped down to 5V through the resistor R2 and the power management chip U4 to provide power for the MCU and temperature sensor circuit. The protection resistor F3 and diode D3 are TVS protection tube and reverse diode, respectively, to provide overvoltage protection for the power circuit.

[0031] like Figure 4 As shown, the control module is an MCU processor. The MCU microcontroller U6 in the figure is the MCU circuit, and a wake-up button is set in the circuit to connect to the microcontroller. The MCU processor U6 is model CH547, and its 16M operating frequency effectively reduces current consumption. J2 is a serial port interface, which is used as the entry point for burning programming source programs. S3 is a wake-up button. When the button is pressed, the MCU can be woken up, and then the system will start working immediately. LED1-3 are three LED indicator lights used to indicate the remaining battery power.

[0032] like Figure 3 and Figure 5As shown, the drive switch module includes transistor Q1, transistor Q2, and voltage regulator U1. The base of transistor Q1 is connected to the output terminal of the control module, the emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to the base of transistor Q2, the emitter of transistor Q2 is connected to the power output terminal of the battery pack, the collector of transistor Q2 is connected to the input terminal of the voltage regulator, and the output terminal of the voltage regulator is connected to the load. Transistor Q1 is an NPN transistor, transistor Q2 is a PNP transistor, and a resistor is connected in series between the emitter and base of transistor Q2.

[0033] When the drive voltage enable IO is high, NPN transistor Q1 and PNP transistor Q2 will be turned on, thereby turning on the drive voltage of 12V. This enables the battery switch and motor start-up circuit to work normally and provide power output to the load.

[0034] like Figure 5 As shown, the temperature detection module includes temperature sensor one J3 and temperature sensor two P16. The detection ends of temperature sensor one and temperature sensor two are respectively set at the protection circuit board and the battery body. The signal ends of temperature sensor one and temperature sensor two are respectively connected to the input end of the control module.

[0035] J3 and P6 are both temperature sensor interfaces used for temperature detection of the MOSFET and the battery itself. Once the temperature exceeds the alarm value, the drive voltage enable will be immediately turned off, shutting down the power output to protect the battery and the circuit itself from overheating and failure.

[0036] like Figure 6 As shown, the load and charging detection module includes a load detection circuit and a charging detection circuit. The detection terminal of the load detection circuit is connected to the power supply terminal on the load, and the output terminal of the load detection circuit is connected to the input terminal of the control module. The input terminal of the charging detection circuit is connected to an external charger, the output terminal is connected to the power supply terminal of the battery pack, and the control terminal is connected to the output terminal of the control module.

[0037] The load detection circuit includes a detection resistor R63, a filter capacitor C31, a transistor Q15, and a diode D5. The detection resistor is connected in series between the power supply terminal of the load and the input terminal of the control module. One end of the filter capacitor is connected to the detection resistor and the control module, and the other end of the filter capacitor is grounded. The power output terminal of the power management chip is connected to the negative terminal of the diode. The positive terminal of the diode is connected to the collector of the transistor and the connection point between the detection resistor and the filter capacitor. The base of the transistor is connected to the output terminal of the control module, and the emitter of the transistor is grounded.

[0038] When the load is turned on, transistor Q15 conducts, and the load current passes through R15, then is filtered by capacitor C31 and enters the microcontroller's AD port, which can detect the real-time load current.

[0039] The charging detection circuit includes transistors Q5 (four), Q17 (five), Q4 (six), Q20 (seven), U3 (one), and U5 (two). The emitter of transistor Q4 is connected to the positive terminal of the external charger, the collector of transistor Q4 is connected to the base of transistor Q5, the emitter of transistor Q5 is grounded, and the collector of transistor Q5 is connected to the input terminal of the control module. The bases of transistors six and seven are respectively connected to one output terminal of the control module, and the emitters of transistors six and seven are both connected to the power output terminal of the power management chip. The collector of transistor six is ​​connected to the gate of MOSFET one, the collector of transistor seven is connected to the gate of MOSFET two, the positive terminal of the external charger is connected to the positive terminal of the battery pack, the negative terminal of the external charger is connected to the source of MOSFET one, the drain of MOSFET one is connected to the source of MOSFET two, and the drain of MOSFET two is connected to the negative terminal of the battery pack. Transistor five is an NPN transistor, and transistors four, six, and seven are all PNP transistors. A resistor is connected in series between the base and emitter of transistors four, six, and seven.

[0040] When the charger is plugged in, transistors Q5 and Q17 are turned on, and the load wake-up IO will notify the microcontroller. When the microcontroller detects that the battery needs to be charged, it will turn on the charging enable IO, so that the charger voltage can be input to the battery to complete the charging function.

[0041] like Figure 7 As shown, the battery voltage detection module consists of N detection units. The total number of detection units is equal to the total number of individual batteries in the power module plus one. One detection unit is connected to the power supply terminal of the battery pack, and the remaining detection units are connected one-to-one with each individual battery in the power module. Each detection unit is a MOSFET. In this embodiment, six detection units are used, and the MOSFETs are Q7, Q10, Q13, Q8, Q11, and Q14.

[0042] The gate of MOSFET 3 is connected to the output terminal of the control module. The drain of MOSFET 3 is connected to the power supply terminal of the corresponding battery after being connected in series with a step-down resistor. The source of MOSFET 3 is connected to the input terminal of the control module. At the same time, an RC circuit is connected to the source of MOSFET 3. The detected voltage is filtered and regulated by a filter resistor and a filter capacitor before being input into the MCU.

[0043] Because the batteries are used in series, the voltage difference between individual cells cannot be too large. Therefore, it is necessary to accurately detect the voltage of each battery. This requires that the voltage detection circuit of each battery be independent. When BatAD is enabled, the corresponding NMOS transistor 2N7002 will turn on. The voltage of the battery is divided by two resistors and then enters the microcontroller to complete the voltage detection function. When sleep mode is required, BatAD is disabled, the detection circuit does not conduct, does not consume current, and enters a low-power mode to minimize the overall power consumption of the circuit.

[0044] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-cell series output battery pack protection circuit, characterized by: The application relates to a battery protection circuit, which comprises a power module, a driving switch module, a control module, a temperature detection module, a load and charging detection module and a battery voltage detection module, wherein the power module comprises a battery pack composed of a plurality of single batteries and a power management chip connected with an output end of the battery pack, the power management chip is used for supplying power to the control module and the temperature detection module, the temperature detection module is used for detecting the protection circuit and the battery body temperature, detection ends of the temperature detection module are arranged at the protection circuit board and the battery body respectively, a signal output end of the temperature detection module is connected with an input end of the control module, detection ends of the load and charging detection module are connected with a power supply end of a load and a charging port of the battery pack respectively, a signal end of the load and charging detection module is connected with an input end of the control module, the battery voltage detection module is connected with single batteries and the whole battery pack respectively, a signal end of the battery voltage detection module is connected with an input end of the control module, an input end of the driving switch module is connected with an output end of the power management chip, an output end of the driving switch module is connected with the load, and the control module is connected with control ends of the load and charging detection module and the driving switch module respectively.

2. A multi-cell series output battery pack protection circuit according to claim 1, wherein: The control module is an MCU processor.

3. The multi-cell series output battery pack protection circuit of claim 1, wherein: The driving switch module comprises a triode one, a triode two and a voltage stabilizer, a base of the triode one is connected with an output end of the control module, an emitter of the triode one is grounded, a collector of the triode one is connected with a base of the triode two, an emitter of the triode two is connected with a power supply output end of the battery pack, a collector of the triode two is connected with an input end of the voltage stabilizer, and an output end of the voltage stabilizer is connected with the load.

4. The multi-cell series output battery pack protection circuit of claim 3, wherein: The triode one is an NPN triode, the triode two is a PNP triode, and a resistor is connected in series between the emitter and the base of the triode two.

5. The multi-cell series output battery pack protection circuit of claim 1, wherein: The temperature detection module comprises temperature sensors one and two, the detection ends of the temperature sensors one and two are arranged at the protection circuit board and the battery body respectively, and the signal ends of the temperature sensors one and two are connected with the input end of the control module.

6. The multi-cell series output battery pack protection circuit of claim 1, wherein: The load and charging detection module comprises a load detection circuit and a charging detection circuit, the detection end of the load detection circuit is connected with the power supply end of the load, the output end of the load detection circuit is connected with the input end of the control module, the input end of the charging detection circuit is connected with an external charger, the output end of the charging detection circuit is connected with the power supply end of the battery pack, and the control end of the charging detection circuit is connected with the output end of the control module.

7. A multi-cell series output battery pack protection circuit according to claim 6, wherein: The load detection circuit comprises a detection resistor, a filter capacitor, a triode three and a diode, the detection resistor is connected in series between the power supply end of the load and the input end of the control module, one end of the filter capacitor is connected with the detection resistor, the other end of the filter capacitor is grounded, the power supply output end of the power management chip is connected with the negative electrode end of the diode, the positive electrode end of the diode is connected with the collector of the triode three and the connection point of the detection resistor and the filter capacitor respectively, the base of the triode three is connected with the output end of the control module, and the emitter of the triode three is grounded.

8. The multi-cell series output battery pack protection circuit of claim 6, wherein: The charging detection circuit comprises a triode four, a triode five, a triode six, a triode seven, a MOS tube one and a MOS tube two, The emitter of the fourth transistor is connected with the positive terminal of the external charger, the collector of the fourth transistor is connected with the base of the fifth transistor, the emitter of the fifth transistor is connected with the ground, and the collector of the fifth transistor is connected with the input terminal of the control module; The base of the sixth transistor and the seventh transistor is connected with the output terminal of the control module respectively, the emitter of the sixth transistor and the seventh transistor is connected with the power output terminal of the power management chip, the collector of the sixth transistor is connected with the gate of the first MOS transistor, and the collector of the seventh transistor is connected with the gate of the second MOS transistor, The positive terminal of the external charger is connected with the positive pole of the battery pack, the negative terminal of the external charger is connected with the source of the first MOS transistor, the drain of the first MOS transistor is connected with the source of the second MOS transistor, and the drain of the second MOS transistor is connected with the negative pole of the battery pack.

9. A multi-cell series output battery pack protection circuit according to claim 8, wherein: The fifth transistor is an NPN transistor, the fourth transistor, the sixth transistor and the seventh transistor are PNP transistors, and a resistor is connected between the base and the emitter of the fourth transistor, the sixth transistor and the seventh transistor.

10. The multi-cell series output battery pack protection circuit of claim 1, wherein: The battery voltage detection module is composed of N detection units, the number of all the detection units is the number of all the single batteries in the power module plus one, one detection unit is connected with the power terminal of the battery pack, and the remaining detection units are connected with all the single batteries in the power module one by one, the detection unit is a third MOS transistor, the gate of the third MOS transistor is connected with the output terminal of the control module, the drain of the third MOS transistor is connected with the power terminal of the corresponding battery, and the source of the third MOS transistor is connected with the input terminal of the control module.

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