CN218335314U - Protection circuit applied to the battery module - Google Patents

Abstract

The utility model discloses a protection circuit applied to a battery module, which includes a self-control protector, a switch element and a voltage clamping circuit; the self-control protector includes a fuse unit and a heater; when the switch element receives a control signal, the switch element will be turned on; when the switching element is turned on, the voltage clamping circuit provides a clamping voltage, and the working current through the self-control protector is clamped within the current range of the fusible fuse unit through the clamp voltage; thus, the self-control protector The fuse unit will be blown by heating the heater with the operating current.

Description

Protection circuit applied to the battery module

technical field

The utility model relates to a protection circuit applied to a battery module, in particular to a protection circuit capable of blowing a fuse of a self-control protector when the voltage of the battery module is in a high voltage state or a low voltage state.

Background technique

In today's battery management system, on the charging path, in addition to overcharging protection through MOSFET switching elements, self-control protectors (SCP) with fuses are also used for overcharging protection.

Furthermore, in the past, self-controlled protectors were only designed for overcharge (or overvoltage) protection, and the fuse of the self-controlled protector was blown in conjunction with the action of the overcharge protection IC. Since the self-control protector is usually only used for overcharge protection, the action voltage range in which the fuse of the self-control protector can be blown is usually outside the voltage of the battery module when the capacity is low. Therefore, if the voltage of the battery module is in a low-voltage state and the self-control protector is used as protection for other abnormalities (such as over-discharge), it will be because the power carried by the heater of the self-control protector is insufficient, for example: the battery If the voltage of the module is too low, the current flowing through the impedance of the heater will become smaller, and the power (P=I ² R) will become smaller, resulting in insufficient power carried by the heater and insufficient heat generation, so that the fusing time of the fuse will be reduced. It is too long or there is a problem that it cannot be fused.

In view of this, the utility model proposes an innovative protection circuit for the battery module. When the voltage of the battery module is in a low voltage state, if the battery module is abnormal (such as over-temperature, over-charging or over-discharging), the protection circuit will still The fuse of the self-control protector can be blown smoothly so as to protect the battery module, which will be the purpose of the present utility model.

Utility model content

The purpose of the utility model is to provide a protection circuit applied to a battery module, the protection circuit includes a self-control protector, a switch element and a voltage clamping circuit. The self-control protector includes a fuse unit and a heater. When the battery module operates in an abnormal state, such as overcharge, overdischarge or overtemperature, the switch element will receive a control signal and be turned on. When the switching element is turned on, the voltage clamping circuit provides a clamping voltage, through which the working current on the heater passing through the self-controlling protector is clamped within the current range of the fusible fuse unit or the voltage across the self-controlling protection The operating voltage on the heater heater is clamped within the voltage range of the blowable fuse unit. In this way, regardless of whether the total voltage of the battery module is in a high voltage state or a low voltage state, the voltage clamping circuit can clamp the operating current or operating voltage on the heater of the self-control protector to the current range or voltage range of the fusible fuse unit Within, so that when the battery module is in an abnormal state of overcharge, overdischarge or overtemperature, the fuse unit can be blown smoothly within a limited time.

In order to achieve the above purpose, the utility model provides a protection circuit applied to the battery module. The battery module includes a plurality of battery cells connected in series. The protection circuit includes: a self-control protector, including a fuse unit and a heater, and a fuse The unit is connected to the positive terminal of the power supply of the battery module, and one end of the heater is connected to the fuse unit; the switch element, when the switch element receives the control signal, the switch element will be turned on; and the voltage clamping circuit, connected to the battery module, self-control protector and switch Components; wherein, when the switching element is turned on, the voltage clamping circuit forms a clamping voltage, and the clamping voltage will clamp the working current through the self-control protector within the current range of the fuse unit, then the fuse unit of the self-control protector The heater is heated by the operating current and is fused.

Preferably, the voltage clamping circuit includes: a first voltage dividing element, one end of which is connected to the positive power terminal of the battery module, and the other end is connected to the first node; a second voltage dividing element, one end of which is connected to the first node, and the other end Connect the negative pole of the power supply of the battery module through the switch element; the voltage clamping element is connected in parallel with the first voltage dividing element; and the power transistor includes a first terminal, a second terminal and a control terminal, the first terminal of the power transistor is connected to the negative pole of the power supply of the battery module, The second terminal of the power transistor is connected to the other terminal of the heater, and the control terminal of the power transistor is connected to the first node; wherein, when the switching element is turned on, the voltage clamping circuit is between the positive terminal of the power supply of the battery module and the control terminal of the power transistor form the clamping voltage.

Preferably, the self-control protector specification has the operating voltage range of the fuse unit, and the voltage clamping circuit forms an operating voltage on the heater, the operating voltage is the voltage difference between the clamping voltage and the conduction voltage of the power transistor, and the operating voltage Clamped by the voltage clamping element within the operating voltage range of the blown fuse unit.

Preferably, the voltage clamping circuit includes a first voltage dividing element and a second voltage dividing element which are respectively resistors, and the resistance of the first voltage dividing element is greater than the resistance of the second voltage dividing element.

Preferably, the voltage clamping element is a Zener diode, and the power transistor is a P-channel metal-oxide-semiconductor field-effect crystal. Preferably, the first terminal of the power transistor is connected to the negative pole of the power supply of the battery module through a power resistor.

In an embodiment of the present invention, the number of strings of battery cells in the battery module is M strings, and the self-control protector is a self-control protector suitable for the specification of the number of strings of N strings of battery cells, where N<M.

Preferably, the switch element is connected to an overcharge protection chip, and when the overcharge protection chip senses that the battery module is in an overcharge state, the overcharge protection chip outputs a control signal to the switch element.

Further, the protection circuit applied to the battery module also includes a microprocessor and an operating parameter sampling chip, the microprocessor is connected to the switching element and the operating parameter sampling chip, and the microprocessor uses the operating parameter sampling chip to control the battery module or the charging and discharging path Sampling at least one operating parameter, and analyzing the operating parameter to determine whether the battery module is operating in an abnormal state, and sending a control signal to the switch element when the battery module is operating in an abnormal state.

Preferably, the operation parameter sampling chip is a chip for sampling current parameters, voltage parameters or temperature parameters.

Description of drawings

Fig. 1 is a circuit block diagram of an embodiment of the utility model protection circuit.

Fig. 2 is a circuit block diagram of another embodiment of the protection circuit of the present invention.

Description of reference signs: 100-battery module; 11-battery core; 13-power input and output port; 200-protection circuit; 201-protection circuit; 21-self-control protector; 211-fuse unit; 2111-first fuse; 2112-second fuse; 213-heater; 23-switching element; 25-voltage clamping circuit; 251-first voltage dividing element; 2511-first node; 252-second voltage dividing element; 253-voltage clamping element; 254-power transistor; 255-power resistor; 27-overcharge protection chip; 270-control signal; 28-microprocessor; 280-control signal; 29-operating parameter sampling chip.

detailed description

Please refer to FIG. 1 , which is a circuit block diagram of an embodiment of the protection circuit of the present invention. As shown in FIG. 1 , the protection circuit 200 of the present invention is applied on the battery module 100 to protect the safety of the battery module 100 during operation. The battery module 100 includes a plurality of battery cells 11 connected in series, the total voltage of which is V _BAT . In an embodiment of the present invention, the number of battery cells 11 connected in series is M series.

The protection circuit 200 includes a self-control protector 21 , a switching element 23 and a voltage clamping circuit 25 . The self-control protector 21 includes a fuse unit 211 and a heater 213 . The fuse unit 211 includes a first fuse 2111 and a second fuse 2112 . One end of the first fuse 2111 is connected to the positive power end of the battery module 100 , one end of the second fuse 2112 is connected to the other end of the first fuse 2111 and the other end is connected to the power input/output port 13 of the battery module 100 . One end of the heater 213 is connected to a connection point between the first fuse 2111 and the second fuse 2112 .

The switching element 23 can also be a transistor switch, which is arranged between the voltage clamping circuit 25 and the negative power supply terminal of the battery module 100 . When the switch element 23 receives the control signal 270 , it will be controlled to conduct by the control signal 270 .

The voltage clamping circuit 25 is connected to the battery module 100 , the self-control protector 21 and the switch element 23 . When the switching element 23 is turned on, the voltage clamping loop 25 provides a clamping voltage V _C . When the switch element 23 is turned on, the self-control protector 21 will pass the working current I _H , and the clamping voltage V _C provided by the voltage clamping circuit 25 will clamp the working current I1 within the current range of the fusible fuse unit 211 .

Further, the voltage clamping circuit 25 includes a first voltage dividing element 251 , a second voltage dividing element 252 , a voltage clamping element 253 and a power transistor 254 . One end of the first voltage dividing element 251 is connected to the positive power end of the battery module 100 , and the other end is connected to the first node 2511 . One end of the second voltage dividing element 252 is connected to the first node 2511 , and the other end is connected to the negative electrode of the battery module 100 through the switch element 23 . The voltage clamping element 253 can also be a Zener diode, which is connected in parallel with the first voltage dividing element 251 . The power transistor 254 includes a first terminal, a second terminal and a control terminal. The first terminal is connected to the negative electrode of the battery module 100 , the second terminal is connected to the other terminal of the heater 213 , and the control terminal is connected to the first node 2511 . In the present invention, the power transistor 254 is a P-channel metal oxide semiconductor field effect transistor (P-MOSFET) or a P-channel field effect transistor (JFET). The first terminal of the power transistor 254 is a drain terminal, the second terminal is a source terminal, and the control terminal is a gate terminal.

The first voltage dividing element 251 and the second voltage dividing element 252 are resistors respectively. The resistance of the first voltage dividing element 251 is greater than the resistance of the second voltage dividing element 252 . When the switch element 23 is turned on, the total voltage V _BAT of the battery module 100 will be divided into a first voltage V1 and a second voltage V2 on the first voltage dividing element 251 and the second voltage dividing element 252 respectively, wherein V1> V2.

Through the constant voltage characteristic of the voltage clamping element 253, the first voltage V1 applied to the self-control protector 21 and the power transistor 254 will be clamped to a fixed clamping voltage V _C , and the clamping voltage VC will be formed in the battery module 100 Between the positive terminal of the power supply and the control terminal of the power transistor 254. Furthermore, the self-control protector 21 regulates the operating voltage range of the fusible fuse unit 211 . The voltage clamping circuit 25 forms an operating voltage V _H on the heater 213 . The working voltage V _H is the voltage difference between the clamping voltage V _C and the conduction voltage (VSG) of the power transistor 254 . The working voltage V _H will be clamped by the voltage clamping element 253 within the operating voltage range of the fusible fuse unit 211 . Then, when the switch element 23 is turned on, the working voltage V _H will be pressed across the heater 213 to pass the working current I _H of the fusible fuse unit 211 through the impedance of the heater 213 .

Then, using the voltage clamping function of the voltage clamping circuit 25, the operating voltage V _H across the heater 213 of the self-control protector 21 is clamped within the operating voltage range of the fusible fuse unit 211, so that the heater 213 The operating current I _H of the fusible fuse unit 211 can be smoothly heated to a sufficient temperature to blow the fuse unit 211 within a limited time.

In an embodiment of the present invention, the power transistor 254 can also be a high-power transistor. The voltage difference (V _BAT −V _H ) between the total voltage V _BAT of the battery module 100 and the self-control protector 21 will be across the power transistor 254, and the energy generated by the voltage difference (V _BAT −V _H ) will be generated by the power Transistor 254 sustains.

Alternatively, in another embodiment of the present invention, the first terminal of the power transistor 254 is connected to the negative pole of the power supply of the battery module 100 through the power resistor 255 . The voltage difference (V _BAT −V _H ) between the total voltage V _BAT of the battery module 100 and the self-control protector 21 will be across the power transistor 254 and the power resistor 255 . In this way, the power resistor 255 can share part of the energy of the voltage difference (V _BAT −V _H ) between the total voltage V _BAT of the battery module 100 and the self-control protector 21, so as to prevent the power transistor 254 from bearing the load of the battery module 100 alone. All the energy of the voltage difference (V _BAT −V _H ) between the total voltage V _BAT and the self-controlling protector 21 poses a risk of being burned out.

Next, various models of self-control protectors (SCP) 21 are designed with different specifications. For example: A type of self-control protector is designed to be suitable for 6-9 series of battery cells and the operating voltage range is 20.2-46.3V; B-type self-control protector is designed for 10-14 series of batteries cell and the operating voltage range is 28.0-62.0V; or, the C-type self-control protector is designed to be suitable for 15-17 series battery cells and the operating voltage range is 39.6-72.0V. Therefore, if a self-control protector 21 with a high number of battery cell strings is selected, the operable voltage range of the fuse unit 211 will be relatively high; relatively, if a self-control protector 21 with a low battery cell string number is selected, The operable voltage range of the fuse unit 211 is relatively low.

In the present invention, the protection circuit 200 will select a self-control protector 21 whose number of strings of battery cells is lower than the actual number of strings of battery cells 11 to protect the battery module 100 . For example, the number of battery cells 11 in the battery module 100 can also be M strings, and the protection circuit 200 selects the self-control protector 21 with N strings of battery cells, where N<M. Then, the self-control protector 21 with a low number of battery cell strings will be applied to the battery module 100 with a higher number of battery cells 11 in series, so that the battery modules 100 with different higher numbers of battery cells 11 in series can all use the same The self-controlled protector 21 of the specification of low number of strings of battery cells is used for protection. For example, a battery module 100 with 10 or more battery cells 11 in series can be protected by a self-control protector 21 with a specification of 6 to 9 battery cell strings.

As mentioned above, regardless of whether the total voltage V _BAT of the battery module 100 is in a high voltage state or a low voltage state, the voltage clamping circuit 25 of the protection circuit 200 can self-control the working voltage V _H on the heater 213 of the protector 21 It is clamped within the action voltage range of the fusible fuse unit 211 , so that the fuse unit 211 can be blown smoothly within a limited time when the battery module 100 is overcharged, overdischarged or overheated. Moreover, the voltage difference (V _BAT -V _H ) between the total voltage V _BAT of the battery module 100 and the self-control protector 21 is borne by the power transistor 254 and/or the power resistor 255, so that it will avoid affecting the The fusing action of the fuse unit 211 of the protector 21 is self-controlled.

Further, the protection circuit 200 also includes an overcharge protection chip 27 connected to the switch element 23 . The overcharge protection chip 27 is connected to the battery module 100 for sensing whether the battery module 100 is in an overcharge (or overvoltage) state. When the overcharge protection chip 27 senses that the battery module 100 is in an overcharge state, the overcharge protection chip 27 will send a control signal 270 to the switch element 23 to control the switch element 23 to conduct. After the switching element 23 is turned on, the voltage clamping circuit 25 will provide a clamping voltage V _C , and the working current I _H or working voltage V _H of the self-control protector 21 is clamped to the fuse unit 211 through the clamping voltage V _C Within the current range or within the voltage range, the fuse unit 211 of the self-control protector 21 can be blown smoothly, preventing the battery module 100 from continuing to charge and discharge through the power input and output ports 13 .

Please refer to the circuit block diagram of another embodiment of the protection circuit of the present invention. As shown in FIG. 2 , the protection circuit 201 of this embodiment further includes a microprocessor 28 and an operating parameter sampling chip 29 . The switch element 23 is connected to the microprocessor 28, and the microprocessor 28 is connected to the operation parameter sampling chip 29 through a connection line (such as a connection line of RS232 standard, UART standard or I2C standard). The operating parameter sampling chip 29 is an Analog Front End (AFE) chip connected to the battery module 100 or the charging and discharging path for sampling current parameters, voltage parameters or temperature parameters of the battery module 100 or the charging and discharging path.

The microprocessor 28 samples at least one operating parameter for the battery module 100 or the charging and discharging path through the operating parameter sampling chip 29, such as sampling the current on the charging and discharging path, sampling the voltage of the battery module 100, or sampling the temperature of the battery module 100, and by analyzing Operating parameters to determine whether the battery module 100 is operating abnormally, for example: whether the battery module 100 is overcharged, overdischarged or overheated, and when the battery module is operating abnormally, send a control signal 280 to the switch element 23 to control the switch element 23 to perform conduction. After the switching element 23 is turned on, the voltage clamping circuit 25 will provide a clamping voltage V _C to clamp the operating current I _H or the operating voltage V _H of the self-control protector 21 to the fusible fuse unit 211 through the clamping voltage V _C Within the current range or voltage range, the fuse unit 211 of the self-control protector 21 can be blown smoothly, preventing the battery module 100 from continuing to charge and discharge through the power input and output ports 13 .

The above is only an embodiment of the utility model, and is not used to limit the implementation scope of the utility model, that is, all equivalent changes made according to the shape, structure, characteristics and spirit of the utility model claims are the same as those described in the claims of the utility model. Modifications should be included in the protection scope of the claims of the present utility model.

Claims (10)

1. A protection circuit applied to a battery module, the battery module comprising a plurality of battery cells connected in series, characterized in that the protection circuit comprises: A self-control protector, including a fuse unit and a heater, the fuse unit is connected to the positive power terminal of the battery module, and one end of the heater is connected to the fuse unit; a switch element, connected to the negative power supply terminal of the battery module, for being turned on when the switch element receives a control signal; and a voltage clamping circuit, connected to the battery module, the self-control protector and the switching element; Wherein, when the switching element is turned on, the voltage clamping circuit forms a clamping voltage, and the clamping voltage clamps the working current passing through the self-control protector within the current range of fusing the fuse unit, Then the fuse unit of the self-control protector is blown by heating the heater by the working current. 2. The protection circuit according to claim 1, wherein the voltage clamping circuit comprises: a first voltage dividing element, one end of which is connected to the positive end of the power supply of the battery module, and the other end is connected to the first node; a second voltage dividing element, one end of which is connected to the first node, and the other end is connected to the negative pole of the power supply of the battery module through the switching element; a voltage clamping element connected in parallel to the first voltage dividing element; and A power transistor, including a first terminal, a second terminal and a control terminal, the first terminal of the power transistor is connected to the negative pole of the power supply of the battery module, and the second terminal of the power transistor is connected to the heater the other end of the power transistor, and the control end of the power transistor is connected to the first node; Wherein, when the switching element is turned on, the voltage clamping circuit forms the clamping voltage between the positive power supply terminal of the battery module and the control terminal of the power transistor. 3. The protection circuit according to claim 2, wherein the self-control protector specification has an operating voltage range for fusing the fuse unit, and the voltage clamping circuit forms an operating voltage on the heater, The working voltage is the voltage difference between the clamping voltage and the turn-on voltage of the power transistor, and the working voltage is clamped by the voltage clamping element within the range of the action voltage for blowing the fuse unit. 4. The protection circuit according to claim 2, wherein the voltage clamping circuit comprises that the first voltage dividing element and the second voltage dividing element are resistors respectively, and the first voltage dividing element The resistance value is greater than the resistance value of the second voltage dividing element. 5 . The protection circuit according to claim 2 , wherein the voltage clamping element is a Zener diode, and the power transistor is a P-channel metal oxide semiconductor field effect transistor or a P-channel field effect transistor. 6. The protection circuit according to claim 2, wherein the first end of the power transistor is connected to the negative pole of the power supply of the battery module through a power resistor. 7. The protection circuit according to claim 1, wherein the number of battery cell strings of the battery module is M strings, and the self-control protector is a self-controlling device suitable for the specification of N strings of battery cell strings. Protector, N<M. 8. The protection circuit according to claim 1, wherein the switching element is connected to an overcharge protection chip, and when the overcharge protection chip senses that the battery module is in an overcharge state, the overcharge The charging protection chip outputs the control signal to the switch element. 9. The protection circuit according to claim 1, further comprising a microprocessor and an operating parameter sampling chip, the microprocessor is connected to the switching element and the operating parameter sampling chip, and the microprocessor Sampling at least one operating parameter for the battery module or the charging and discharging path through the operating parameter sampling chip, and analyzing the at least one operating parameter to judge whether the battery module is operating in an abnormal state, and The module sends out the control signal to the switch element when the module operates in the abnormal state. 10. The protection circuit according to claim 9, wherein the operating parameter sampling chip is a chip for sampling current parameters, voltage parameters or temperature parameters.

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