A section-by-section charging control circuit for a battery pack

Abstract

The utility model provides a kind of charging control circuit for battery pack, its technical scheme main point includes: a plurality of settings in battery pack and series connection battery, and charging interface for external charger, switch circuit for conducting or disconnecting the electric connection between each battery anode and charging interface anode is equipped, switch circuit is electrically connected with time sequence control circuit, for when charging interface external charger, in turn and cyclically to each battery corresponding switch circuit is carried out on-off control, so that the switch circuit of some battery corresponding in battery pack is in conducting state, the switch circuit of remaining battery corresponding in battery pack is in off state, to each battery in battery pack is carried out cyclically charging by section;The utility model can avoid the power safety hazard generated by using wrong charger, solve the problem that charger of different model battery pack is difficult to share, facilitate charging to battery pack in practical application.

Description

Technical Field

[0001] This utility model relates to the field of charging management technology, and in particular to a cell-by-cell charging control circuit for a battery pack. Background Technology

[0002] Battery packs are widely used in portable power supplies and various portable power tools, such as electric drills, electric screwdrivers, and portable chainsaws. A typical battery pack structure includes a casing, several batteries connected in series, and a circuit board usually housed within the casing for charge and discharge management. Because existing battery packs require different output voltages from the charger depending on the number of batteries connected in series, and because current battery pack chargers typically use a boost circuit to match the voltage of the corresponding battery pack model to ensure the charger's output voltage matches the battery pack's rated charging voltage, dedicated chargers are usually required for different battery pack models, making it difficult to use chargers for different battery pack models interchangeably.

[0003] In practical applications of battery packs, dedicated chargers are easily forgotten, and the difficulty in replacing them with commonly used chargers, such as mobile phone chargers, leads to charging inconvenience and affects the use of power tools. Furthermore, human error in using the wrong charger can create electrical safety hazards. Since battery packs typically use lithium batteries, with a single lithium battery cell generally having a voltage of 4.2V, while mobile phone chargers typically output 5V, charging the batteries in the pack cell by cell, even with a mobile phone charger, is possible. Therefore, charging each cell individually standardizes the charger's voltage output requirements, avoiding charging inconvenience and electrical safety hazards caused by using the wrong charger in practical applications. Utility Model Content

[0004] To facilitate battery pack charging in practical applications, avoid electrical safety hazards caused by using the wrong charger, and solve the problem of incompatibility of chargers for different battery pack models, this utility model provides a cell-by-cell charging control circuit for battery packs, the technical solution of which is as follows: A cell-by-cell charging control circuit for a battery pack includes: a plurality of batteries disposed in the battery pack and connected in series, and a charging interface for connecting an external charger. A switching circuit for connecting or disconnecting the electrical connection between the positive terminal of each battery and the positive terminal of the charging interface is provided. The switching circuit is electrically connected to a timing control circuit, which sequentially and cyclically controls the switching circuits corresponding to each battery when an external charger is connected to the charging interface, so that when the switching circuit corresponding to a certain battery is in the conducting state, the switching circuits corresponding to the other batteries in the battery pack are in the disconnected state, so as to cyclically charge each battery in the battery pack.

[0005] Preferably, the switching circuit includes MOSFETs Q1, Q2, Q3, and Q4; the gates G of MOSFETs Q1 and Q2 are electrically connected to the timing control circuit; the source S of MOSFET Q1 is grounded; the drain D of MOSFET Q1 is electrically connected to the drain D of MOSFET Q2; and the source S of MOSFET Q2 is electrically connected to the negative terminal of the corresponding battery. The gates G of MOSFETs Q3 and Q4 are both electrically connected to the drain D of MOSFET Q2; the source S of MOSFET Q3 is electrically connected to the positive terminal of the charging interface; the drain D of MOSFET Q3 is electrically connected to the drain D of MOSFET Q4; and the source S of MOSFET Q4 is electrically connected to the positive terminal of the corresponding battery.

[0006] Preferably, MOSFET Q1 is of the same type as MOSFET Q2, MOSFET Q3 is of the same type as MOSFET Q4, MOSFET Q1 is of the opposite type to MOSFET Q3, MOSFET Q1 and MOSFET Q2 are N-channel MOSFETs, and MOSFET Q3 and MOSFET Q4 are P-channel MOSFETs.

[0007] Preferably, the switching circuit includes MOSFET Q5, MOSFET Q6, diode D1, and diode D2; the gate G of MOSFET Q5 is electrically connected to the timing control circuit, the source S of MOSFET Q5 is grounded, the drain D of MOSFET Q5 is electrically connected to the negative terminal of diode D1, and the positive terminal of diode D1 is electrically connected to the negative terminal of the corresponding battery; the gate G of MOSFET Q6 is electrically connected to the drain D of MOSFET Q5, the source S of MOSFET Q6 is electrically connected to the positive terminal of the charging interface, the drain D of MOSFET Q6 is electrically connected to the positive terminal of diode D2, and the negative terminal of diode D2 is electrically connected to the positive terminal of the corresponding battery.

[0008] Preferably, the types of MOSFET Q5 and MOSFET Q6 are opposite; MOSFET Q5 is an N-channel MOSFET, and MOSFET Q6 is a P-channel MOSFET.

[0009] Preferably, the timing control circuit is a monostable trigger circuit, including a plurality of monostable triggers. The battery, the switching circuit and the monostable triggers are respectively in one-to-one correspondence. The output terminal of each monostable trigger is electrically connected to the corresponding switching circuit. The input terminals and output terminals of all monostable triggers are connected in series in sequence. The output terminal of the last monostable trigger is electrically connected to the input terminal of the first monostable trigger to form a cyclic control structure.

[0010] Preferably, the timing control circuit can also employ a microcontroller control circuit, a bistable trigger circuit, a delay circuit, or a time control circuit.

[0011] Preferably, the segment-by-segment charging control circuit is an integrated circuit, which is integrated on the original circuit board inside the battery pack and electrically connected to the charging circuit of the battery pack; or the segment-by-segment charging control circuit is separately integrated on a circuit board and electrically connected to the charging circuit of the battery pack.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model features a simple structure and reliable function. Compared with the charging circuit structure of existing battery packs, it incorporates a timing control circuit and a switching circuit between the positive terminal of each battery and the positive terminal of the charging interface. When an external charger is connected to the charging interface, the timing control circuit sequentially and cyclically controls the on / off state of the switching circuits corresponding to each battery. This ensures that when the switching circuit corresponding to one battery is in a conducting state, the switching circuits corresponding to the other batteries in the battery pack are in a de-energized state, thus cyclically charging each battery in the battery pack. This effectively unifies the voltage output requirements of the charger, solves the problem of incompatibility between chargers for different battery pack models, avoids electrical safety hazards caused by using the wrong charger, and allows users to replace the dedicated charger for the battery pack with a common mobile phone charger when they forget to bring their own. This facilitates charging the battery pack in practical applications. Attached Figure Description

[0013] The objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts in the description, wherein: Figure 1 This is a block diagram of the step-by-step charging control circuit; Figure 2 The circuit diagram of the step-by-step charging control circuit is shown when the switching circuit is the first embodiment. Figure 3 The circuit diagram of the step-by-step charging control circuit is shown in the second embodiment when the switching circuit is used. In the diagram: 1 is the battery; 2 is the charging interface; 3 is the switching circuit; 4 is the timing control circuit. Detailed Implementation

[0014] The technical features of this utility model will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can understand them.

[0015] A cell-by-cell charging control circuit for a battery pack, the circuit structure of which is as follows: Figures 1-3As shown, the device includes: several batteries 1 arranged in series within a battery pack, and a charging interface 2 for connecting an external charger. A switching circuit 3 is provided between the positive terminal of each battery 1 and the positive terminal of the charging interface 2 to connect or disconnect the electrical connection between them. The switching circuit 3 is electrically connected to a timing control circuit 4, which sequentially and cyclically controls the on / off state of the switching circuit 3 corresponding to each battery 1 when an external charger is connected to the charging interface 2. This ensures that when the switching circuit 3 corresponding to a certain battery 1 is in the on state, the switching circuits 3 corresponding to the remaining batteries 1 in the battery pack are in the off state, thus controlling the on / off state of each battery in the battery pack sequentially. Battery 1 is cyclically charged; the timing control circuit 4 sequentially controls the switching circuit 3 corresponding to each battery 1 to be turned on for a period of time and then return to the off state. During the on period of time, a charging circuit is formed to realize cyclic charging of each battery. This solves the problem that chargers for different battery pack models are difficult to use together, avoids electrical safety hazards caused by using the wrong charger, and allows users to replace the dedicated charger of the battery pack with a commonly used low-voltage charger, such as a mobile phone charger, to cyclically charge several batteries 1 in the battery pack, so that users can charge the battery pack in actual use.

[0016] Specifically, the first embodiment of the switching circuit 3 is, for example... Figure 2 As shown, the switching circuit 3 includes MOSFETs Q1, Q2, Q3, and Q4. The gates G of MOSFETs Q1 and Q2 are electrically connected to the timing control circuit 4. The source S of MOSFET Q1 is grounded, and the drain D of MOSFET Q1 is electrically connected to the drain D of MOSFET Q2. The source S of MOSFET Q2 is electrically connected to the negative terminal of the corresponding battery 1. The gates G of MOSFETs Q3 and Q4 are electrically connected to the drain D of MOSFET Q2. The source S of MOSFET Q3 is electrically connected to the positive terminal of the charging interface 2, and the drain D of MOSFET Q3 is electrically connected to the drain D of MOSFET Q4. The source S of MOSFET Q4 is electrically connected to the positive terminal of the corresponding battery 1. The function of MOSFETs Q2 and Q4 is to prevent damage to the battery 1 and the sequential charging control circuit when the positive and negative terminals of the charger are reversed.

[0017] Furthermore, MOSFET Q1 is of the same type as MOSFET Q2, and MOSFET Q3 is of the same type as MOSFET Q4. The types of MOSFET Q1 and MOSFET Q3 are opposite. MOSFETs Q1 and Q2 are N-channel MOSFETs, while MOSFETs Q3 and Q4 are P-channel MOSFETs. When the gate G of MOSFETs Q1 and Q2 is high, their source S and drain D are connected; when the gate G is low, they are cut off. When the gate G of MOSFETs Q3 and Q4 is low, their source S and drain D are connected; when the gate G is high, they are cut off.

[0018] Specifically, when the switching circuit 3 is the first embodiment, the operation process of the step-by-step charging control circuit is as follows: When the charging interface 2 is normally connected to the charger, a pulse is generated at the moment of power-on as the initial trigger signal of the timing control circuit 4, causing the timing control circuit 4 to start. At this time, the switching circuit 3 corresponding to the first battery 1 receives the control signal, and the gates G of MOSFETs Q1 and Q2 turn high, turning on MOSFETs Q1 and Q2. At the same time, the gates G of MOSFETs Q3 and Q4 turn low, turning on MOSFETs Q3 and Q4, forming a complete charging circuit, and the charger charges the first battery 1. When the charging period ends, in the switching circuit 3 corresponding to the first battery 1, the gates G of MOSFETs Q1 and Q2 turn low, turning off MOSFETs Q1 and Q2, and the charging circuit is disconnected. Similarly, when the timing control circuit 4 outputs control signals to the switching circuit 3 corresponding to the next battery 1 in sequence, the corresponding battery 1 is connected to the charger, forming a complete charging circuit. This cycle can be repeated to achieve the sequential charging control of the battery pack.

[0019] Specifically, a second embodiment of the switching circuit 3 is, for example... Figure 3 As shown, the switching circuit 3 includes MOSFETs Q5 and Q6, diodes D1 and D2; the gate G of MOSFET Q5 is electrically connected to the timing control circuit 4, the source S of MOSFET Q5 is grounded, the drain D of MOSFET Q5 is electrically connected to the negative terminal of diode D1, and the positive terminal of diode D1 is electrically connected to the negative terminal of the corresponding battery 1; the gate G of MOSFET Q6 is electrically connected to the drain D of MOSFET Q5, the source S of MOSFET Q6 is electrically connected to the positive terminal of the charging interface 2, the drain D of MOSFET Q6 is electrically connected to the positive terminal of diode D2, and the negative terminal of diode D2 is electrically connected to the positive terminal of the corresponding battery 1; the function of diodes D1 and D2 is to prevent damage to the battery 1 and the sequential charging control circuit when the positive and negative terminals of the charger are reversed.

[0020] Furthermore, the types of MOSFETs Q5 and Q6 are opposite; MOSFET Q5 is an N-channel MOSFET, while MOSFET Q6 is a P-channel MOSFET. When the gate G of MOSFET Q5 is high, its source S and drain D are connected, and it is cut off when the gate G is low. When the gate G of MOSFET Q6 is low, its source S and drain D are connected, and it is cut off when the gate G is high.

[0021] Specifically, when the switching circuit 3 is the second embodiment, the operation process of the step-by-step charging control circuit is as follows: When the charging interface 2 is normally connected to the charger, a pulse is generated at the moment of power-on as the initial trigger signal of the timing control circuit 4, causing the timing control circuit 4 to start. At this time, the switching circuit 3 corresponding to the first battery 1 receives the control signal, causing the gate G of MOSFET Q5 to turn high, MOSFET Q5 to conduct, and the gate G of MOSFET Q6 to turn low, MOSFET Q6 to conduct, forming a complete charging circuit, and the charger charges the first battery 1. When the charging period ends, in the switching circuit 3 corresponding to the first battery 1, the gate G of MOSFET Q5 turns low, causing MOSFET Q5 to turn off, and the charging circuit is disconnected. Similarly, when the timing control circuit 4 outputs control signals to the switching circuit 3 corresponding to the next battery 1 in sequence, the corresponding battery 1 is connected to the charger, forming a complete charging circuit. This cycle can be repeated to achieve the sequential charging control of the battery pack.

[0022] Specifically, such as Figure 2 or Figure 3 As shown, the first embodiment of the timing control circuit 4 employs a monostable trigger circuit, including several monostable triggers. A monostable trigger, also known as a monostable multivibrator or monostable pulse generator, is a trigger with two stable states. When the input of a monostable trigger receives a trigger signal, it can transition from one stable state to another and maintain this new state for a period of time, called the steady-state width or pulse width. Then, it automatically returns to the initial stable state. Moreover, this steady-state width is fixed and independent of the width of the trigger signal. The battery 1, the switching circuit 3, and the monostable triggers are respectively in one-to-one correspondence. The output of each monostable trigger is electrically connected to the corresponding switching circuit 3. The inputs and outputs of all monostable triggers are connected in series. The output of the last monostable trigger is electrically connected to the input of the first monostable trigger to form a cyclic control structure.

[0023] In addition, the timing control circuit 4 can also adopt a microcontroller control circuit, a bistable trigger circuit, a delay circuit, a time control circuit, etc. The function of the timing control circuit is to sequentially control the switching circuit 3 to turn on and off with delay, and to form a charging circuit for a single battery cell 1 during the delay period, so as to realize the battery pack's cell-by-cell charging control.

[0024] Specifically, the segment-by-segment charging control circuit is an integrated circuit, which is integrated on the existing circuit board inside the battery pack and electrically connected to the charging circuit of the battery pack. Alternatively, the segment-by-segment charging control circuit can be independently integrated on a separate circuit board and electrically connected to the charging circuit of the battery pack. Different application designs can be selected according to the shape, structure, and volume requirements of the battery pack. The method of independently integrating the segment-by-segment charging control circuit on a separate circuit board can facilitate the modification of the charging circuit of the existing battery pack during production, so as to promote the application of the segment-by-segment charging control circuit.

[0025] The embodiments described herein are merely preferred embodiments of the present invention and are not limited to the precise structures described above and shown in the accompanying drawings. Various modifications and changes can be made without departing from the scope of protection of the present invention. Any variations and improvements made by engineers in the art to the technical solutions of the present invention without departing from the design concept of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A cell-by-cell charging control circuit for a battery pack, characterized in that: The battery pack includes several batteries (1) connected in series within the battery pack, and a charging interface (2) for connecting an external charger. A switch circuit (3) for connecting or disconnecting the electrical connection between the positive terminal of each battery (1) and the positive terminal of the charging interface (2) is provided. The switch circuit (3) is electrically connected to a timing control circuit (4) for sequentially and cyclically controlling the switching circuit (3) corresponding to each battery (1) when an external charger is connected to the charging interface (2). This ensures that when the switch circuit (3) corresponding to a certain battery (1) is in the conducting state, the switch circuit (3) corresponding to the other batteries (1) in the battery pack is in the disconnected state, so as to cyclically charge each battery (1) in the battery pack.

2. The cell-by-cell charge control circuit for a battery pack of claim 1, wherein: The switching circuit (3) includes MOS transistors Q1, Q2, Q3, and Q4; the gates G of MOS transistors Q1 and Q2 are electrically connected to the timing control circuit (4), the source S of MOS transistor Q1 is grounded, the drain D of MOS transistor Q1 is electrically connected to the drain D of MOS transistor Q2, and the source S of MOS transistor Q2 is electrically connected to the negative terminal of the corresponding battery (1); the gates G of MOS transistors Q3 and Q4 are electrically connected to the drain D of MOS transistor Q2, the source S of MOS transistor Q3 is electrically connected to the positive terminal of the charging interface (2), the drain D of MOS transistor Q3 is electrically connected to the drain D of MOS transistor Q4, and the source S of MOS transistor Q4 is electrically connected to the positive terminal of the corresponding battery (1).

3. The cell-by-cell charging control circuit for a battery pack of claim 2, wherein: MOSFET Q1 is of the same type as MOSFET Q2, MOSFET Q3 is of the same type as MOSFET Q4, and MOSFET Q1 is of the opposite type to MOSFET Q3. MOSFETs Q1 and Q2 are N-channel MOSFETs, while MOSFETs Q3 and Q4 are P-channel MOSFETs.

4. The cell-by-cell charging control circuit for a battery pack of claim 1, wherein: The switching circuit (3) includes a MOS transistor Q5, a MOS transistor Q6, a diode D1, and a diode D2; the gate G of the MOS transistor Q5 is electrically connected to the timing control circuit (4), the source S of the MOS transistor Q5 is grounded, the drain D of the MOS transistor Q5 is electrically connected to the negative terminal of the diode D1, and the positive terminal of the diode D1 is electrically connected to the negative terminal of the corresponding battery (1); the gate G of the MOS transistor Q6 is electrically connected to the drain D of the MOS transistor Q5, the source S of the MOS transistor Q6 is electrically connected to the positive terminal of the charging interface (2), the drain D of the MOS transistor Q6 is electrically connected to the positive terminal of the diode D2, and the negative terminal of the diode D2 is electrically connected to the positive terminal of the corresponding battery (1).

5. The cell-by-cell charging control circuit for a battery pack of claim 4, wherein: The types of MOSFET Q5 and MOSFET Q6 are opposite; MOSFET Q5 is an N-channel MOSFET, while MOSFET Q6 is a P-channel MOSFET.

6. The cell-by-cell charging control circuit for a battery pack according to claim 1, characterized in that: The timing control circuit (4) is a monostable trigger circuit, which includes several monostable triggers. The battery (1), the switching circuit (3) and the monostable triggers are respectively in one-to-one correspondence. The output terminal of each monostable trigger is electrically connected to the corresponding switching circuit (3). The input and output terminals of all monostable triggers are connected in series in sequence. The output terminal of the last monostable trigger is electrically connected to the input terminal of the first monostable trigger to form a cyclic control structure.

7. The section-by-section charge control circuit for a battery pack of claim 1, wherein: The timing control circuit (4) can also employ a microcontroller control circuit, a bistable trigger circuit, a delay circuit, and a time control circuit.

8. The cell-by-cell charging control circuit for a battery pack of any one of claims 1 to 7, wherein: The segment-by-segment charging control circuit is an integrated circuit, which is integrated on the original circuit board inside the battery pack and electrically connected to the charging circuit of the battery pack, or the segment-by-segment charging control circuit is independently integrated on a circuit board and electrically connected to the charging circuit of the battery pack.

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