CN119070439A

CN119070439A - Battery pack protection circuit, battery pack

Info

Publication number: CN119070439A
Application number: CN202411255360.6A
Authority: CN
Inventors: 焦岩浩; 钟棣林; 黄锋
Original assignee: Innosecco Shenzhen Semiconductor Co ltd
Current assignee: Innosecco Shenzhen Semiconductor Co ltd
Priority date: 2024-09-09
Filing date: 2024-09-09
Publication date: 2024-12-03

Abstract

The invention discloses a protection circuit of a battery pack and the battery pack. The battery pack comprises a first battery connecting end and a second battery connecting end, wherein each battery connecting end is correspondingly provided with at least one external connecting end, at least one external connecting end is correspondingly provided with a bidirectional conducting device, each bidirectional conducting device comprises at least one bidirectional transistor, the battery connecting ends are electrically connected with the external connecting ends through the bidirectional transistors, the protection circuit comprises at least one driving module which corresponds to the bidirectional conducting devices one by one and comprises a protection input end, a conducting voltage input end and a driving output end, the protection input end is used for inputting protection signals, the conducting voltage input end is used for inputting conducting voltages, the driving output end is electrically connected with the control end of the bidirectional transistors, the conducting voltages are used for bidirectionally conducting the bidirectional transistors, and the driving module is used for responding to the protection signals and controlling the conducting voltage input end and the driving output end to be conducted or disconnected. The invention can drive the bidirectional conduction transistor in the battery pack.

Description

Protection circuit of battery pack and battery pack

Technical Field

The invention relates to the technical field of battery pack charge and discharge protection, in particular to a protection circuit of a battery pack and the battery pack.

Background

The battery pack plays an important role in new energy technology and has wide application in the field of new energy. It is also increasingly important how to protect the charge and discharge process of the battery pack.

In the related art, the battery pack is controlled to be turned on and off in both directions by using two silicon-based MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) connected in series, both of which are controlled to be charged or discharged. And the two silicon-based MOSFETs connected in series are adopted, so that more components are arranged in the battery pack, and the whole volume of the battery pack is larger. In the related art, the use of one bi-directional pass transistor instead of two MOSFETs in series reduces the overall volume of the battery pack. However, the related art lacks a driving circuit for the bidirectional on transistor.

Disclosure of Invention

The invention provides a protection circuit of a battery pack and the battery pack so as to drive a bidirectional conduction transistor in the battery pack.

According to an aspect of the present invention, there is provided a protection circuit for a battery pack, wherein the battery pack includes a first battery connection terminal and a second battery connection terminal, each of the battery connection terminals is provided with at least one external connection terminal, at least one of the external connection terminals is provided with a bidirectional conduction device, the bidirectional conduction device includes at least one bidirectional transistor, and the battery connection terminal is electrically connected with the external connection terminal through the bidirectional transistor;

The protection circuit includes:

At least one driving module corresponding to the bidirectional conduction devices one by one, wherein the driving module comprises a protection input end, a conduction voltage input end and a driving output end;

The protection input end is used for inputting a protection signal, the conduction voltage input end is used for inputting a conduction voltage, the driving output end is electrically connected with the control end of the bidirectional transistor, the conduction voltage is used for conducting the bidirectional transistor in a bidirectional mode, and the driving module is used for responding to the protection signal and controlling time delay conduction or time delay disconnection between the conduction voltage input end and the driving output end.

Optionally, the driving module further comprises a pull-down input end, wherein the pull-down input end is used for inputting a pull-down signal, and the driving module is further used for responding to the protection signal and controlling the connection or disconnection between the pull-down input end and the driving output end.

Optionally, the driving module further comprises a main switch unit, a first delay control unit, a second delay control unit and a pull-down switch unit;

the first end of the main switch unit is electrically connected with the conducting voltage input end, and the second end of the main switch unit is electrically connected with the driving output end;

The first input end of the first delay control unit is electrically connected with the protection input end, and the output end of the first delay control unit is electrically connected with the control end of the main switch unit; the first delay control unit is used for switching on the main switch unit after a first delay when the protection signal is at a first level, and switching off the main switch unit after a second delay when the protection signal is at a second level;

The first end of the pull-down switch unit is electrically connected with the driving output end, the second end of the pull-down switch unit is electrically connected with the pull-down input end, the first input end of the second delay control unit is electrically connected with the protection input end, the output end of the second delay control unit is electrically connected with the control end of the pull-down switch unit, the second delay control unit is used for switching off the pull-down switch unit after a third delay when the protection signal is at a first level, and switching on the pull-down switch unit after a fourth delay when the protection signal is at a second level;

the first delay is larger than the third delay, the second delay is smaller than the fourth delay, and the first level is different from the second level in height.

Optionally, the first delay unit includes a first resistor, a first diode, a second resistor, a second diode, a first capacitor, and a first transistor;

the first end of the first resistor is electrically connected with the protection input end, the second end of the first resistor is electrically connected with the anode of the first diode, and the cathode of the first diode is electrically connected with the first end of the first capacitor;

the first end of the second resistor is electrically connected with the protection input end, the second end of the second resistor is electrically connected with the cathode of the second diode, and the anode of the second diode is electrically connected with the first end of the first capacitor;

The first electrode of the first transistor is electrically connected with the control end of the main switch unit, the second electrode of the first transistor is electrically connected with the pull-down input end, and the control electrode of the first transistor is electrically connected with the first end of the first capacitor;

the second delay unit comprises a third resistor, a fourth resistor, a second capacitor, a third diode, a fourth diode and a second transistor;

the first end of the third resistor is electrically connected with the protection input end, and the second end of the third resistor is electrically connected with the anode of the third diode;

The first end of the fourth resistor is electrically connected with the protection input end, the second end of the fourth resistor is electrically connected with the cathode of the fourth diode, and the anode of the fourth diode is electrically connected with the first end of the second capacitor;

The first end of the second transistor is connected with a preset voltage, the second pole of the second transistor is electrically connected with the pull-down input end, the control pole of the second transistor is electrically connected with the first end of the second capacitor, the second end of the second capacitor is electrically connected with the pull-down input end, and the first pole of the second transistor is electrically connected with the control pole of the pull-down switch unit;

the first capacitor is equal to the second capacitor, the first resistance is larger than the third resistance, and the second resistance is smaller than the fourth resistance.

Optionally, the first delay control unit includes a first controller, and the second delay control unit includes a second controller.

Optionally, each battery connection end is correspondingly provided with two external connection ends, namely a charging connection end and a discharging connection end, the battery pack comprises a first bidirectional conduction device and a second bidirectional conduction device, the first bidirectional conduction device corresponds to the charging connection end, and the second bidirectional conduction device corresponds to the discharging connection end;

The protection circuit comprises a first driving module and a second driving module, wherein the protection input end of the first driving module is used for inputting a charging protection signal, and the driving output end of the first driving module is electrically connected with the control electrode of the bidirectional transistor in the second bidirectional conduction device;

The protection input end of the second driving module is used for inputting a discharge protection signal, and the driving output end of the second driving module is electrically connected with the control electrode of the bidirectional transistor in the first bidirectional conduction device.

Optionally, the fourth resistance in the first driving module is smaller than the fourth resistance in the second driving module.

Optionally, the protection circuit further includes:

The recharging protection module is electrically connected with the first driving module and the control electrode of the bidirectional transistor in the second bidirectional conduction device; the recharging protection module is used for responding to a first level of recharging protection signals, turning off a first transistor and a pull-down switch unit in the first driving module after a fifth delay, and conducting electric connection between a control electrode of a bidirectional transistor in the second bidirectional conduction device and a unidirectional conduction voltage input end after a sixth delay, wherein the unidirectional conduction voltage input end is used for inputting unidirectional conduction voltage, the unidirectional conduction voltage is used for controlling the bidirectional transistor in the second bidirectional conduction device to be conducted unidirectionally from the battery connection end to the external connection end, and the fifth delay is smaller than the sixth delay;

The recharging protection module is also used for responding to a second level of the recharging protection signal, turning off the output to the first transistor and the pull-down switch unit in the first driving module after a seventh delay, turning off the electric connection between the control electrode of the bidirectional transistor in the second bidirectional conduction device and the unidirectional conduction voltage input end after an eighth delay, and the seventh delay is larger than the eighth delay.

Optionally, the recharging protection module includes:

a fifth resistor, a sixth resistor, a fifth diode, a sixth diode, a third capacitor, a third transistor, and a fourth transistor;

The first end of the fifth resistor is electrically connected with a recharging protection signal input end, the recharging protection signal input end is used for inputting the recharging protection signal, the second end of the fifth resistor is electrically connected with the anode of the fifth diode, the cathode of the fifth diode is electrically connected with the first end of the third capacitor, the first end of the sixth resistor is electrically connected with the recharging protection signal input end, the second end of the sixth resistor is electrically connected with the cathode of the sixth diode, the anode of the sixth diode is electrically connected with the first end of the third capacitor, the second end of the third capacitor is electrically connected with the pull-down input end, the control electrode of the third transistor is electrically connected with the first end of the third capacitor, the first electrode of the third transistor is electrically connected with the control electrode of the first transistor in the first driving module, the second electrode of the third transistor is electrically connected with the pull-down input end, the control electrode of the fourth transistor is electrically connected with the first end of the fourth transistor;

the recharging protection module further comprises a seventh resistor, an eighth resistor, a seventh diode, an eighth diode, a fourth capacitor, a fifth transistor, a sixth transistor and a seventh transistor;

The first end of the seventh resistor is electrically connected with the anode of the seventh diode, the cathode of the seventh diode is electrically connected with the first end of the fourth capacitor, the first end of the eighth resistor is electrically connected with the cathode of the eighth diode, the anode of the eighth diode is electrically connected with the first end of the fourth capacitor, the second end of the fifth transistor is electrically connected with the pull-down input terminal, the control electrode of the fifth transistor is electrically connected with the first end of the fourth capacitor, the first electrode of the fifth transistor is electrically connected with the control electrode of the sixth transistor and the control electrode of the seventh transistor;

The seventh resistance is greater than the fifth resistance, and the sixth resistance is greater than the eighth resistance.

According to another aspect of the present invention, there is provided a battery pack including the protection circuit of the battery pack as described above;

The battery pack comprises a battery unit, wherein the first battery connecting end is electrically connected with the positive electrode of the battery unit, and the second battery connecting end is electrically connected with the negative electrode of the battery unit;

The first battery connecting end is correspondingly provided with the protection circuit.

According to the technical scheme, the adopted protection circuit of the battery pack comprises at least one driving module corresponding to the bidirectional conduction devices one by one, the driving module comprises a protection input end, a conduction voltage input end and a driving output end, the protection input end is used for inputting protection signals, the conduction voltage input end is used for inputting conduction voltages, the driving output end is electrically connected with a control end of the bidirectional transistor, the conduction voltages are used for bidirectionally conducting the bidirectional transistor, and the driving module is used for responding to the protection signals and controlling delay conduction or delay disconnection between the conduction voltage input end and the driving output end. The protection circuit not only can control the on and off of the bidirectional transistor, but also can enable the protection signal to adopt lower voltage because the protection signal does not directly drive the bidirectional transistor, and is easier to realize.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic circuit diagram of a protection circuit of a battery pack according to an embodiment of the present invention;

Fig. 2 is a schematic circuit diagram of a battery pack according to an embodiment of the present invention;

Fig. 3 is a schematic circuit diagram of a protection circuit of a battery pack according to another embodiment of the present invention;

fig. 4 is a schematic circuit diagram of a first driving module according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a second driving module according to an embodiment of the present invention;

Fig. 6 is a schematic circuit diagram of another battery pack according to an embodiment of the present invention;

fig. 7 is a schematic circuit diagram of a recharging protection module according to an embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements that are expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic circuit diagram of a protection circuit of a battery pack according to an embodiment of the present invention, and fig. 2 is a schematic circuit diagram of a battery pack according to an embodiment of the present invention, referring to fig. 1 and fig. 2. The battery pack comprises a first battery connecting end BAT+ and a second battery connecting end BAT-, wherein each battery connecting end is correspondingly provided with at least one external connecting end, at least one external connecting end is correspondingly provided with a bidirectional conducting device, each bidirectional conducting device comprises at least one bidirectional transistor T, the battery connecting end is electrically connected with the external connecting end through the bidirectional transistor T, the protection circuit 1 comprises at least one driving module 11 which is in one-to-one correspondence with the at least one bidirectional conducting device, the driving module 11 comprises a protection input end DG, a conducting voltage input end VPUMP and a driving output end OUT, the protection input end DG is used for inputting a protection signal, the conducting voltage input end VPUMP is used for inputting a conducting voltage, the driving output end OUT is electrically connected with a control end of the bidirectional transistor T, the driving module 11 is used for responding to the protection signal and controlling delay conduction or delay disconnection between the conducting voltage input end VPUMP and the driving output end OUT.

Specifically, the protection circuit 1 of the battery pack may be applied to the battery pack to protect the charging and/or discharging process of the battery pack. The battery pack comprises a battery unit 3, and a plurality of battery cells connected in series and/or in parallel are arranged inside the battery unit 3. In this embodiment, the battery pack includes a first battery connection terminal bat+ and a second battery connection terminal bat—two battery connection terminals. The first battery connection terminal bat+ may be connected to the positive electrode of the battery cell 3, and the second battery connection terminal BAT-may be connected to the negative electrode of the battery cell 3. Each battery connection terminal corresponds to at least one external connection terminal, and the external connection terminals may include at least one charging connection terminal and at least one discharging connection terminal. The charging connection is used for connecting a charging loop so as to charge the battery unit 3, and the discharging connection is used for connecting a load loop so as to enable the battery unit 3 to supply power for the load loop. Illustratively, as shown in fig. 2, the first battery connection terminal corresponds to a charging connection terminal c+ and a discharging connection terminal p+.

At least one external connection terminal is electrically connected with the corresponding battery connection terminal through a bidirectional transistor. For example, the charging connection terminal c+ may be electrically connected to the first battery connection terminal bat+ through a bidirectional transistor, the discharging connection terminal p+ may be electrically connected to the first battery connection terminal bat+ through two unidirectional transistors connected in series, the charging connection terminal c+ may be electrically connected to the first battery connection terminal bat+ through two unidirectional transistors connected in series, and the discharging connection terminal p+ may be electrically connected to the first battery connection terminal bat+ through a bidirectional transistor, preferably, as shown in fig. 2, the charging connection terminal c+ is electrically connected to the first battery connection terminal bat+ through a first bidirectional conduction device, and the discharging connection terminal p+ is electrically connected to the first battery connection terminal bat+ through a second bidirectional conduction device. Each bidirectional conduction device comprises at least one bidirectional transistor, and when the bidirectional conduction device is applied to a scene with lower voltage, the bidirectional conduction device can be provided with one bidirectional transistor, and when the bidirectional conduction device is applied to a scene with higher voltage, the bidirectional conduction device can be provided with at least two bidirectional transistors connected in parallel. The bidirectional transistor is, for example, a gallium nitride transistor or the like.

Each bidirectional conduction device corresponds to one driving module 11, that is, when the battery pack includes n bidirectional conduction devices, the protection circuit includes n driving modules 11, where n is an integer greater than or equal to 1. The driving module 11 is electrically connected with the corresponding bidirectional conduction device and is used for controlling all bidirectional transistors in the bidirectional conduction device to be turned on or turned off in a delayed manner according to the protection signal.

The protection signal is output by the processing unit 2, for example, and the processing unit 2 can control the charge and discharge states of the battery pack according to parameters such as current and voltage of the battery unit 3. The processing unit 2 is, for example, an AFE (Active Front End) chip. The AFE chip may output the charge protection signal CHG and the discharge protection signal DSG.

When the external connection terminal and the battery connection terminal are connected by the silicon-based MOSFET, the charging protection signal CHG and the discharging protection signal DSG need to directly drive the control electrodes of the corresponding silicon-based MOSFETs. On the one hand, the charging protection signal CHG and the discharging protection signal DSG are required to be turned on to the corresponding silicon-based MOSFETs, and on the other hand, the high-level values of the charging protection signal CHG and the discharging protection signal DSG are required to be larger than the value of the first battery connection terminal bat+ for the high side of the battery pack, i.e., for the protection circuit to be applied between the first battery connection terminal and the external connection terminal, on the other hand, the charging protection signal CHG and the discharging protection signal DSG are required to have a faster response speed and can be timely adjusted according to the state of the battery pack, and the AFE chip required to meet the above two aspects is smaller in selectivity and higher in implementation difficulty.

In this embodiment, after the protection signal (the charge protection signal CHG or the discharge protection signal DSG) passes through the driving module 11, the corresponding bidirectional transistor is controlled in a delay manner. For example, when the protection signal is at the first level, it indicates that conduction is required between the battery connection terminal and the corresponding external connection terminal, so that the battery pack is charged or discharged. When the protection signal is at the second level, the battery connection end and the corresponding external connection end need to be turned off, so as to protect the battery pack. The first level is different from the second level in height, for example, the first level is a high level, and the second level is a low level, or the first level is a low level, and the second level is a high level. In this embodiment, the first level is a high level, and the second level is a low level. When the protection signal is at the first level, the driving module 11 delays and turns on the turn-on voltage input terminal VPUMP and the driving output terminal OUT, so that the turn-on voltage can be output to the control electrode of the corresponding bidirectional transistor. When the protection signal is at the second level, the driving module 11 delays and turns off the path between the on voltage input terminal VPUMP and the driving output terminal OUT, so that the on voltage cannot be output to the control electrode of the bidirectional transistor, and the bidirectional transistor is turned off. In this embodiment, the state of the bidirectional transistor is controlled by the delay, and the driving module 11 has more time to perform additional control on the control electrode of the bidirectional transistor, so that the control on the bidirectional transistor does not occur simultaneously, and thus a short circuit occurs between the on voltage input terminal and the additionally arranged module, so that the safety is higher.

As can be seen from the above analysis, the protection circuit in this embodiment is provided with the driving module, so that the protection signal does not need to directly drive the bidirectional transistor. The first level of the guard signal may be small relative to a direct drive silicon-based MOSFET. Under the requirements of the first level of the protection signal is smaller and the response speed of the protection signal is high, the AFE chip is more in selection and lower in implementation difficulty. For the on-voltage, the on-voltage is only required to be larger than a certain threshold value with the voltage of the corresponding battery connection terminal, and the faster response speed is not required. In other words, the protection signal in this embodiment only needs to satisfy the faster response speed, and does not need to satisfy the condition that the first level is larger. Therefore, the protection circuit of the present embodiment is easier to implement.

According to the technical scheme, the battery pack protection circuit comprises at least one driving module corresponding to the bidirectional conduction devices one by one, the driving module comprises a protection input end, a conduction voltage input end and a driving output end, the protection input end is used for inputting protection signals, the conduction voltage input end is used for inputting conduction voltages, the driving output end is electrically connected with a control end of the bidirectional transistor, the conduction voltages are used for bidirectionally conducting the bidirectional transistor, and the driving module is used for responding to the protection signals and controlling delay conduction or delay disconnection between the conduction voltage input end and the driving output end. The protection circuit not only can control the on and off of the bidirectional transistor, but also can enable the protection signal to adopt lower voltage because the protection signal does not directly drive the bidirectional transistor, and is easier to realize.

In the above embodiment, the first pole of the bidirectional transistor is electrically connected to the battery connection terminal, and the second pole of the bidirectional transistor is electrically connected to the external connection terminal. The first pole and the second pole of the bidirectional transistor are respectively two drains of the bidirectional transistor, and the control of the bidirectional transistor is the grid electrode of the bidirectional transistor.

Illustratively, as shown in fig. 1, the driving module 11 includes a main switching unit Q1, a first terminal of the main switching unit Q1 is electrically connected to the on-voltage input terminal VPUMP, a second terminal of the main switching unit Q1 is electrically connected to the driving output terminal OUT, and a control terminal of the main switching unit Q1 is electrically connected to the protection input terminal DG. The control terminal of the main switch unit Q1 may be directly electrically connected to the protection input terminal DG, and preferably the control terminal of the main switch unit Q1 is indirectly electrically connected to the protection input terminal DG through a first delay control unit (to be described later). In addition, the following description will be given by taking an example in which the first bidirectional conduction device includes a first bidirectional transistor T1, and the second bidirectional conduction device includes a second bidirectional transistor T2.

Optionally, fig. 3 is a schematic circuit diagram of a protection circuit of another battery pack according to an embodiment of the present invention, and refer to fig. 3. The driving module 11 further includes a pull-down input terminal DGND for inputting a pull-down signal, and the driving module 11 is further configured to control on or off between the pull-down input terminal DGND and the driving output terminal OUT in response to the protection signal.

Specifically, the pull-down signal input from the pull-down input terminal DGND may pull the potential of the driving output terminal OUT low, i.e., the potential of the control electrode of the bidirectional transistor. When the protection signal controls the turn-off between the turn-on voltage input terminal VPUMP and the driving output terminal OUT, the bidirectional transistor needs to be turned off. However, since the control electrode of the bidirectional transistor has no potential input and the potential thereof may be unstable, the embodiment turns on the pull-down input terminal DGND and the driving output terminal OUT when the bidirectional transistor needs to be turned off by setting the pull-down input terminal DGND, thereby ensuring that the bidirectional transistor can be effectively turned off. The pull-down input DGND may be connected to the second battery connection BAT-.

Illustratively, as shown in fig. 3, the driving module 11 includes a pull-down switching unit Q2, a first terminal of the pull-down switching unit Q2 is electrically connected to the driving output terminal OUT, a second terminal of the pull-down switching unit Q2 is electrically connected to the pull-down input terminal DGND, and a control terminal of the pull-down switching unit Q2 is electrically connected to the protection input terminal DG. The pull-down switching unit Q2 is turned off in response to a first level of the protection signal and turned on in response to a second level of the protection signal. It should be noted that, of course, the control terminal of the pull-down switch unit Q2 may be directly electrically connected to the protection input terminal DG, or may be indirectly electrically connected to the second delay control unit (to be described later).

For convenience of explanation, the following will take the example that the protection circuit is applied to the high side of the battery pack. The protection circuit includes two driving modules 11, i.e., a first driving module 11A and a second driving module 11B, where the first driving module 11A is used for driving the bidirectional crystal in the second bidirectional conduction device, i.e., driving the second bidirectional transistor T2, and the second driving module 11B is used for driving the bidirectional transistor in the first bidirectional conduction device, i.e., driving the first bidirectional transistor T1. Fig. 4 is a schematic circuit diagram of a first driving module according to an embodiment of the present invention, and fig. 5 is a schematic circuit diagram of a second driving module according to an embodiment of the present invention. Referring to fig. 2,4 and 5, the driving module 11 includes a main switching unit (a first main switching unit Q25 in fig. 4, a second main switching unit Q32 in fig. 5), a first delay control unit (a first delay control unit 111A in fig. 4, a second first delay control unit 111B in fig. 5), a second delay control unit (a first second delay control unit 112A in fig. 4, a second delay control unit 112B in fig. 5) and a pull-down switching unit (a first pull-down switching unit Q28 in fig. 4, a second pull-down switching unit Q35 in fig. 5). The first input end of the first delay control unit is electrically connected with the protection input end, the output end of the first delay control unit is electrically connected with the control end of the main switch unit, the first delay control unit is used for conducting the main switch unit after the first delay when the protection signal is at a first level, switching off the main switch unit after the second delay when the protection signal is at a second level, the first input end of the second delay control unit is electrically connected with the protection input end, the output end of the second delay control unit is electrically connected with the control end of the pull-down switch unit, the second delay control unit is used for switching off the pull-down switch unit after the third delay when the protection signal is at the first level, and conducting the pull-down switch unit after the fourth delay when the protection signal is at the second level, wherein the first delay is greater than the third delay, and the second delay is less than the fourth delay.

Specifically, the working principles of the first driving module and the second driving module are the same, and this embodiment is described by taking the working principle of the first driving module as an example. For the first driving module, the protection input terminal is a discharge protection input terminal DDSG, which is connected to the discharge protection signal DSG output by the processing unit, and the pull-down input terminals in this embodiment are all connected to the second battery connection terminal BAT-. When the discharge protection signal DSG transitions from the first level (high level) to the second level (low level), it indicates that the second bidirectional transistor T2 needs to be turned off. In this embodiment, after the signal at the discharge protection input DDSG jumps to the low level, the first main switch unit Q25 is not turned off directly, but the first delay control unit 111A turns off the first main switch unit Q25 after the second delay, and similarly, the first pull-down switch unit Q28 is not turned on directly, but the first pull-down switch unit Q28 is turned on after the fourth delay by the first second delay control unit 112A. The second delay is smaller than the fourth delay, that is, after the signal at the discharge protection output DDSG jumps to a low level, the first delay control unit turns off the first main switching unit Q25, cuts off the path between the on voltage input terminal VPUMP and the driving output terminal (the first driving output terminal vgate_q2 in fig. 4), and then turns on the first pull-down switching unit Q28 by the first second delay control unit 112A, so that the first driving output terminal vgate_q2 and the pull-down input terminal are turned on, and the second bidirectional transistor is completely turned off, thereby realizing discharge protection. When the discharge protection is released, that is, the discharge protection signal DSG transitions from the low level to the high level, the first delay control unit 111A turns on the first main switch unit Q25 after a first delay, and the first second delay control unit 112A turns on the first pull-down switch unit Q28 after a third delay. The first delay is greater than the third delay, that is, when the discharge protection signal DSG transitions from low level to high level, the first pull-down switch unit Q28 is turned off by the first second delay control unit 112A, the pull-down path of the first driving output terminal vgate_q2 is cut off, and then the first main switch unit Q25 is turned on by the first delay control unit 111A, so that the on voltage input terminal VPUMP is turned on with the first driving output terminal vgate_q2 again. According to the setting of the embodiment, the conduction voltage input end VPUMP does not have the moment of being conducted with the pull-down input end, so that the two input ends are prevented from being short-circuited.

Optionally, with continued reference to fig. 4 and 5, the first delay unit includes a first resistor, a first diode, a second resistor, a second diode, a first capacitor and a first transistor, where a first end of the first resistor is electrically connected to the protection input terminal, a second end of the first resistor is electrically connected to an anode of the first diode, a cathode of the first diode is electrically connected to a first end of the first capacitor, a first end of the second resistor is electrically connected to the protection input terminal, a second end of the second resistor is electrically connected to a cathode of the second diode, an anode of the second diode is electrically connected to a first end of the first capacitor, a first pole of the first transistor is electrically connected to a control end of the main switch unit, a second pole of the first transistor is electrically connected to a pull-down input terminal, a control pole of the first transistor is electrically connected to a first end of the first capacitor, a second end of the first capacitor is electrically connected to a pull-down input terminal of the first capacitor, a second end of the second capacitor is electrically connected to a second end of the first resistor, a second resistor is electrically connected to a second end of the second resistor, a second end of the second resistor is electrically connected to a pull-down input terminal of the second resistor, a second end of the second resistor is electrically connected to a pull-down input terminal of the second resistor, the first electrode of the second transistor is electrically connected with the control electrode of the pull-down switch unit, the first capacitor is equal to the second capacitor, the first resistance is larger than the third resistance, and the second resistance is smaller than the fourth resistance.

Specifically, taking fig. 4 as an example, in the first driving module, the first resistor is a resistor R123, the first diode is a diode D13, the second resistor is a resistor R127, the second diode is a diode D16, the first capacitor is a capacitor C53, the first transistor is a transistor Q29, the preset voltage is 5V, the third resistor is a resistor R124, the third diode is a diode D14, the fourth resistor is a resistor R128, the fourth diode is a diode D17, the second capacitor is a capacitor C54, and the second transistor is a transistor Q30.

When the discharge protection signal DSG is at a low level, the capacitor C53 is discharged faster than the capacitor C54 because the resistor R127 is smaller than the resistor R128 and the capacitor C53 is equal to the capacitor C54. The delay loop consisting of the resistor R127, the diode D16 and the capacitor C53 pulls the voltage of the gate electrode of the transistor Q29 low, so that the transistor Q29 is turned off, and the path between the first main switching unit Q25 and the pull-down input terminal is turned off, and the first main switching unit Q25 is turned off, so that the path between the on voltage input terminal VPUMP and the first driving output terminal vgate_q2 is cut off. Subsequently, the delay loop composed of the resistor R128, the diode D17 and the capacitor C54 pulls the potential of the transistor Q30 low, and the transistor Q30 is turned off, so that the preset voltage is written into the control terminal of the first pull-down switch unit Q28, and the first pull-down switch unit Q28 is turned on, so that the first driving output terminal vgate_q2 is turned on with the pull-down input terminal.

When the discharge protection signal DSG is at a high level, since the resistor R123 is larger than the resistor R124, the charging speed of the capacitor C53 is smaller than the charging speed of the capacitor C54. Therefore, the delay circuit composed of the resistor R124, the diode D14 and the capacitor C54 pulls the potential of the gate electrode of the transistor Q30 high, and the transistor Q30 is turned on, so that the potential of the control end of the first pull-down unit Q28 is pulled down, the first pull-down unit Q28 is turned off, and the path between the first driving output end vgate_q2 and the pull-down input end is cut off. The delay loop composed of the resistor R123, the diode D13 and the capacitor C53 pulls up the potential of the control electrode of the transistor Q29, so that the transistor Q29 is turned on, the pull-down input end is turned on with the first main switch unit Q25, and the first main switch unit Q25 is turned on, and the turn-on voltage input end VPUMP is turned on with the first driving output end vgate_q2.

The main switch unit may be a PNP triode, the pull-down switch unit may be an NMOS tube, and the first transistor and the second transistor may be NMOS tubes.

Optionally, as shown in fig. 4, the first driving module further includes a resistor R112, a capacitor C40, a resistor R113, a resistor R131, a resistor R132, a resistor R120, a resistor R122, a resistor R126, and a resistor R118, which are used to form a peripheral circuit of the first driving module, and may be used for filtering, current limiting, etc., and the specific connection structure is shown in fig. 4 and will not be repeated here.

It should be noted that, referring to fig. 5, in the second driving module, the first resistor is a resistor R144, the first diode is a diode D28, the second resistor is a resistor R151, the second diode is a diode D35, the first capacitor is a capacitor C57, the first transistor is a transistor Q36, the preset voltage is 5V, the third resistor is a resistor R145, the third diode is a diode D33, the fourth resistor is a resistor R152, the fourth diode is a diode D36, the second capacitor is a capacitor C58, and the second transistor is a transistor Q37. The protection input is a charging protection input DCHG, which is connected to the charging protection signal CHG output by the processing unit. The driving output terminal is a second driving output terminal vgate_q1, which is electrically connected to the control electrode of the first bidirectional transistor T1.

The second driving module further includes a resistor R133, a capacitor C55, a resistor R136, a resistor R134, a resistor R141, a resistor R155, a resistor R180, a resistor R142, a resistor R143, a resistor R147, and a resistor R140, which are used to form a peripheral circuit of the first driving module, and may be used for filtering, current limiting, etc., and the specific connection structure is shown in fig. 4 and will not be repeated here.

As can be seen from the above analysis, the protection circuit of the present embodiment can realize normal charge and discharge (the discharge protection signal is at a high level, the charge protection signal is at a high level), discharge protection (the charge protection signal is at a high level, the discharge protection signal is at a low level), and charge protection (the charge protection signal is at a low level, the discharge protection signal is at a high level) and other operation modes.

Optionally, in some other embodiments, the first delay control unit includes a first controller and the second delay control unit includes a second controller. In this embodiment, the delay control unit is implemented by using a controller, so that the delay time can be controlled by programming or the like. The controller is, for example, a single chip microcomputer or an FPGA (Field Programmable GATE ARRAY ) or the like.

Optionally, the fourth resistance in the first driving module is smaller than the fourth resistance in the second driving module. The second capacitance in the first driving module is equal to the second capacitance in the second driving module. More preferably, the parameters of other corresponding components in the first driving module and the second driving module are equal. So set up for when discharge protection signal and the protection signal that charges are the low level, discharge protection's action is faster, and first drive output VGate_Q2 promptly is pulled down more soon promptly, avoids first drive output and second drive output to be pulled down simultaneously the interference scheduling problem that appears each other.

Of course, in other embodiments, the fourth resistance in the first driving module may be set equal to the fourth resistance in the second driving module.

Optionally, fig. 6 is a schematic circuit diagram of another battery pack according to an embodiment of the present invention, fig. 7 is a schematic circuit diagram of a recharging protection module according to an embodiment of the present invention, and referring to fig. 6 and fig. 7, the protection circuit further includes a recharging protection module 12. The recharging protection module 12 is electrically connected with the first driving module 11A and the control electrode of the bidirectional transistor in the second bidirectional conduction device (namely, the control electrode of the second bidirectional transistor T2), the recharging protection module 12 is used for responding to the first level of the recharging protection signal, turning off the first transistor in the first driving module 11A and the pull-down switch unit after a fifth delay, conducting the electrical connection between the control electrode of the bidirectional transistor in the second bidirectional conduction device and the unidirectional voltage input end b+ after a sixth delay, wherein the unidirectional voltage input end b+ is used for inputting unidirectional voltage, the unidirectional voltage is used for controlling the bidirectional transistor in the second bidirectional conduction device to be unidirectional conducted from the battery connection end to the external connection end, the fifth delay is smaller than the sixth delay, the recharging protection module 12 is also used for responding to the second level of the recharging protection signal, turning off the output of the first transistor in the first driving module 11A and the pull-down switch unit after a seventh delay, turning off the control electrode of the bidirectional transistor in the second bidirectional conduction device and the unidirectional voltage input end b+ after a eighth delay, and the unidirectional voltage input end b+ is larger than the eighth delay.

Specifically, in the recharging protection mode, the second bidirectional transistor T2 is controlled to be in a unidirectional conduction state, so that the battery unit is unidirectional conducted between the discharging connection terminals p+, and the discharging connection terminals p+ cannot recharge the battery unit. The recharging protection signal may be input by the recharging protection signal input terminal ReP, and the recharging protection signal may be output by the processing unit 2. The unidirectional conduction voltage input terminal b+ may be directly connected to the first battery connection terminal bat+ of the battery cell 3, and the unidirectional conduction voltage is smaller than the conduction voltage input from the conduction voltage input terminal VPUMP. When the unidirectional conduction voltage is applied to the control electrode of the second bidirectional transistor T2, the second bidirectional transistor T2 is equivalent to a diode, thereby achieving unidirectional conduction.

In this embodiment, when the recharging protection is needed, the recharging protection module 12 turns off the first transistor after the fifth delay, thereby turning off the first main switch unit, and turns off the pull-down switch unit after the fifth delay, that is, turns off the path between the voltage input terminal VPUMP and the first driving output terminal vgate_q2 and the path between the first driving output terminal vgate_q2 and the pull-down input terminal in the first driving module after the fifth delay, and turns on the path between the unidirectional voltage input terminal and the control electrode of the second bidirectional transistor after the sixth delay. When the recharging protection is released, the recharging protection module 12 turns off the path between the unidirectional voltage input end and the control electrode of the second bidirectional transistor after the eighth delay, and turns off the output to the first transistor and the first pull-down switch unit after the seventh delay, so that the first main switch unit can be driven to be conducted by other signals, and the pull-down switch unit can also be driven to be conducted by other signals after the seventh delay. The first transistor and the pull-down transistor can be controlled to be turned on or off by the discharge protection signal DSG after the seventh delay. During recharging protection, the first transistor and the pull-down transistor are both turned on no matter what state the discharging protection signal is. In the arrangement of this embodiment, the unidirectional conduction voltage input terminal, the conduction voltage input terminal VPUMP and the pull-down input terminal are not conducted simultaneously, so as to avoid a short circuit between the input terminals.

Illustratively, as shown in FIG. 6, the recharging protection module 12 comprises a fifth resistor R137, a sixth resistor R139, a fifth diode D23, a sixth diode D27, a third capacitor C56, a third transistor Q33 and a fourth transistor Q34, wherein a first end of the fifth resistor R137 is electrically connected with a recharging protection signal input end ReP, the recharging protection signal input end ReP is used for inputting a recharging protection signal, a second end of the fifth resistor R137 is electrically connected with an anode of the fifth diode D23, a cathode of the fifth diode D23 is electrically connected with a first end of a third capacitor C56, a first end of the sixth resistor R139 is electrically connected with the recharging protection signal input end ReP, a second end of the sixth resistor R139 is electrically connected with a cathode of the sixth diode D27, an anode of the sixth diode D27 is electrically connected with a first end of the third capacitor C56, a second end of the third capacitor C56 is electrically connected with a pull-down input end, a control electrode of the third transistor Q33 is electrically connected with a control electrode of the third capacitor C56, a control electrode of the third transistor Q33 is electrically connected with a control electrode of the third capacitor C33, a third end of the third resistor D33 is electrically connected with a third end of the third capacitor C56, a third transistor Q1 is electrically connected with a third end of the third transistor Q33;

the recharging protection module further comprises a seventh resistor R125, an eighth resistor R130, a seventh diode D15, an eighth diode D20, a fourth capacitor C52, a fifth transistor Q31, a sixth transistor Q26 and a seventh transistor Q27;

The sixth transistor Q26 and the seventh transistor Q27 are connected in series between the unidirectional conduction voltage input terminal B+ and the control electrode of the bidirectional transistor in the second bidirectional conduction device, the first end of the seventh resistor R125 is electrically connected with the recharging protection signal input terminal ReP, the second end of the seventh resistor R125 is electrically connected with the anode of the seventh diode D15, the cathode of the seventh diode D15 is electrically connected with the first end of the fourth capacitor C52, the first end of the eighth resistor R130 is electrically connected with the recharging protection signal input terminal ReP, the second end of the eighth resistor R130 is electrically connected with the cathode of the eighth diode D20, the anode of the eighth diode D20 is electrically connected with the first end of the fourth capacitor C52, the second end of the fourth capacitor C52 is electrically connected with the pull-down input terminal, the control electrode of the fifth transistor Q31 is electrically connected with the first end of the fourth capacitor C52, the first electrode of the fifth transistor Q31 is electrically connected with the control electrode of the sixth transistor Q26 and the seventh transistor Q27, and the fifth transistor Q31 is electrically connected with the pull-down input terminal. The third capacitor is equal to the fourth capacitor, the seventh resistor R125 is greater than the fifth resistor R137, and the sixth resistor R139 is greater than the eighth resistor R130.

When the recharging protection signal is at a high level, the delay loop formed by the fifth resistor R137, the fifth diode D23 and the third capacitor C56 turns on the third transistor Q33 and the fourth transistor Q34 first, so that the control poles of the first transistor and the pull-down switch unit in the first driving module are pulled down, thereby turning off the first main switch unit and the pull-down switch unit, and turning off the path between the on voltage input terminal VPUMP and the first driving output terminal vgate_q2. Then, the delay loop formed by the seventh resistor R125, the seventh diode D15, and the fourth capacitor C52 turns on the sixth transistor Q26 and the seventh transistor Q27, and turns on the path between the control electrode of the second bidirectional transistor and the unidirectional-conduction voltage input terminal b+, and the second bidirectional transistor turns on unidirectionally.

When the recharging protection is released, the fifth transistor Q31 is turned off through the delay loop formed by the eighth resistor R130, the eighth diode D20 and the fourth capacitor C52, so that the sixth transistor Q26 and the seventh transistor Q27 are also turned off, that is, the path between the control electrode of the second bidirectional transistor and the unidirectional voltage input terminal b+ is turned off. The delay loop formed by the sixth resistor R139, the sixth diode D27, and the third capacitor C56 then turns off the third transistor Q33 and the fourth transistor Q34, so that the path between the first pole DDSG of the third transistor Q33 and the pull-down input terminal is turned off, the first transistor may be turned on or off by the discharge protection signal, and the path between the first pole DDSG of the fourth transistor Q34 and the pull-down input terminal is turned off, and the first pull-down switching unit may be turned on or off by the discharge protection signal.

Optionally, as shown in fig. 7, the recharging protection module further includes a capacitor C37, a resistor R116, a zener diode D12, a resistor R115, a resistor R129, a capacitor C51, and a resistor R138, which form a current limiting or filtering structure, and the specific connection manner is shown in fig. 7 and will not be described herein.

The embodiment of the invention also provides a battery pack, as shown in fig. 2, the battery pack comprises the protection circuit of the battery pack provided by any embodiment of the invention, the battery pack further comprises a battery unit 3, a first battery connecting end is electrically connected with the positive electrode of the battery unit, a second battery connecting end is electrically connected with the negative electrode of the battery unit, and the first battery connecting end is correspondingly provided with the protection circuit. The battery pack provided by the embodiment of the invention comprises the protection circuit of the battery pack provided by any embodiment of the invention, so that the battery pack has the same beneficial effects and is not repeated here.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.

The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. The protection circuit of the battery pack is characterized in that the battery pack comprises a first battery connecting end and a second battery connecting end, at least one external connecting end of at least one external connecting end is correspondingly arranged on each battery connecting end, a bidirectional conduction device is correspondingly arranged on at least one external connecting end, the bidirectional conduction device comprises at least one bidirectional transistor, and the battery connecting end is electrically connected with the external connecting end through the bidirectional transistor;

The protection circuit includes:

2. The protection circuit of the battery pack according to claim 1, wherein the driving module further comprises a pull-down input terminal for inputting a pull-down signal, and wherein the driving module is further configured to control on or off between the pull-down input terminal and the driving output terminal in response to the protection signal.

3. The protection circuit of the battery pack according to claim 2, wherein the driving module further comprises a main switching unit, a first delay control unit, a second delay control unit, and a pull-down switching unit;

4. The protection circuit of the battery pack according to claim 3, wherein the first delay unit includes a first resistor, a first diode, a second resistor, a second diode, a first capacitor, and a first transistor;

5. The protection circuit of the battery pack according to claim 3, wherein the first delay control unit includes a first controller, and the second delay control unit includes a second controller.

6. The protection circuit of a battery pack according to claim 4, wherein each battery connection terminal is provided with two external connection terminals of a charging connection terminal and a discharging connection terminal, the battery pack includes a first bidirectional conduction device and a second bidirectional conduction device, the first bidirectional conduction device corresponds to the charging connection terminal, and the second bidirectional conduction device corresponds to the discharging connection terminal;

7. The protection circuit of the battery pack of claim 6, wherein a fourth resistance in the first drive module is less than a fourth resistance in the second drive module.

8. The protection circuit of the battery pack according to claim 6, further comprising:

9. The protection circuit of the battery pack according to claim 8, wherein the recharging protection module comprises:

10. A battery pack, characterized in that the battery pack comprises the protection circuit of the battery pack according to any one of claims 1 to 9;