Detection circuit of battery protection board, battery management system and battery pack

Abstract

The utility model belongs to the technical field of battery protection, and particularly relates to a detection circuit of a battery protection board, a battery management system and a battery pack. The detection circuit comprises a chip, a plurality of detection ends, a plurality of switch units and an output end, the detection ends are electrically connected with pins of the chip and used for detecting voltage and battery temperature and transmitting the voltage and the battery temperature to the chip, the switch units are connected in series, the switch units are electrically connected with the pins of the chip, each switch unit comprises an MOS tube, and the output end is electrically connected with the chip. Parts of the switch units are connected in parallel with resistors, and the output end is connected with the multiple switch units. Each switch unit can receive a level signal of the chip so as to control the on or off of the MOS tube, so that the current output by the output end passes through or does not pass through the resistor, and the voltage output by the output end is further changed. According to the utility model, detection and output of a plurality of fault detection signals are realized through a single output end, so that the design of the battery protection board is more concise and efficient.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery protection, and in particular relates to a detection circuit of a battery protection board, a battery management system and a battery pack. Background Art

[0002] In the prior art, battery protection boards are used to monitor multiple parameters of battery packs, including but not limited to battery voltage, current, temperature, etc., to ensure safe operation of the battery. These protection boards usually require multiple signal ports to transmit different monitoring signals, which makes the design of battery packs and related equipment complicated and increases costs. In addition, as power tools and other battery-driven devices have higher requirements for efficiency and performance, higher requirements are placed on the integration and intelligence level of battery management systems (BMS). Utility Model Content

[0003] The purpose of the utility model is to at least solve the problem of how to output multiple protection signals through one port. This purpose is achieved through the following technical solutions:

[0004] The first aspect of the utility model provides a detection circuit of a battery protection board, comprising:

[0005] chip;

[0006] A plurality of detection terminals, wherein the plurality of detection terminals are electrically connected to the chip;

[0007] A plurality of switch units, wherein the plurality of switch units are connected in series with each other, the plurality of switch units are electrically connected to the chip, the switch units include MOS tubes, and some of the switch units are connected in parallel with resistors;

[0008] An output end is electrically connected to the plurality of switch units.

[0009] According to the detection circuit of the utility model, the detection circuit electrically connects multiple detection terminals to the chip, and multiple switch units to the chip, each switch unit includes a MOS tube (MOSFET, i.e., a metal oxide semiconductor field effect transistor), and some switch units are connected in parallel with resistors, so that the detection circuit can flexibly detect and respond to different states of the battery according to whether the resistor divides the voltage. Specifically, when the voltage between the gate (the gate is the control terminal) and the source (the source is the input or output terminal of the current) of the MOS tube is less than the threshold voltage, the MOS tube is closed. At this time, the semiconductor channel is non-conductive, and the current from the drain (the drain is the output or input terminal of the current) to the source is blocked. The MOS tube is in a cut-off state, and the current passes through the resistor. Conversely, when the voltage between the gate and the source is greater than the threshold voltage, the MOS tube is opened. In this state, the electric field causes the semiconductor material to form a conductive channel between the source and the drain, allowing current to flow. When the MOS tube is in the cut-off state, the current passes through the resistor, and the voltage at the output end changes. The value of the changing voltage can be used to know how many resistors have passed through, so as to understand which switch unit's MOS tube is in the cut-off state, and thus determine that the detection signal of the detection end connected to the switch unit is abnormal, and there are problems such as overcharging, over-discharging or over-high charging temperature. The utility model realizes the output of multiple fault detection signals through a single output end, making the design of the battery protection board more concise and efficient.

[0010] In addition, the detection circuit according to the utility model may also have the following additional technical features:

[0011] In some embodiments of the present invention, the chip includes a first output pin, the switch unit includes a first switch unit, and the first output pin is electrically connected to the first switch unit through a transistor.

[0012] In some embodiments of the present invention, the chip further includes a plurality of output pins, and the plurality of output pins are connected to the switch units in a one-to-one correspondence.

[0013] In some embodiments of the present invention, the detection end is connected to a thermistor, and the thermistor is used to detect the temperature of the battery.

[0014] In some embodiments of the present invention, the detection end is respectively connected to the positive electrode or the negative electrode of the battery.

[0015] In some embodiments of the present invention, a variable resistor is connected between the output end and the switch unit.

[0016] In some embodiments of the present invention, the output end is connected to a ground wire.

[0017] In some embodiments of the present invention, the chip is connected to a ground line.

[0018] A second aspect of the utility model provides a battery management system, including the detection circuit of the battery protection board mentioned above.

[0019] A third aspect of the present invention provides a battery pack, comprising the above-mentioned battery management system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0021] Figure 1 The circuit structure diagram of the detection circuit according to the embodiment of the utility model is schematically shown.

[0022] The reference numerals are as follows:

[0023] 100, detection circuit; 10, chip; 20, detection end; 30, switch unit; 31, first MOS tube; 32, second MOS tube; 33, third MOS tube; 34, first resistor; 35, second resistor;

[0024] 40. Thermistor; 50. Transistor; 60. Output terminal. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0026] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0027] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0028] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both above and below orientations.

[0029] like Figure 1As shown, according to an embodiment of the utility model, a detection circuit 100 of a battery protection board is proposed, and the detection circuit 100 includes a chip 10, multiple detection terminals 20 (including a detection terminal 20 for detecting voltage and a detection terminal 20 connected to a thermistor 40 for detecting temperature), multiple switch units 30 and an output terminal 60, wherein the detection terminal 20 for detecting voltage among the multiple detection terminals 20 is electrically connected to the pin of the chip 10 for detecting voltage and transmitting it to the chip 10, the detection terminal 20 connected to the thermistor 40 among the multiple detection terminals 20 is used to detect temperature and transmit it to the chip 10, and the multiple switch units 30 are connected in series with each other, and the multiple switch units 30 are electrically connected to the pin of the chip 10. Specifically, the plurality of switch units 30 include three, each of which includes a MOS tube, which corresponds to the first MOS tube 31 (Q3), the second MOS tube 32 (Q4) and the third MOS tube 33 (Q5), and some of the switch units 30 are connected in parallel with the first resistor 34 (R13), specifically, the second MOS tube 32 (Q4) and the third MOS tube 33 (Q5) are connected in parallel with the first resistor 34 (R13), and the output end 60 is connected to the plurality of switch units 30. Each switch unit 30 can receive the level signal of the chip 10 to control the conduction or cutoff of the first MOS tube 31 (Q3), the second MOS tube 32 (Q4) or the third MOS tube 33 (Q5), so that the current output by the output end 60 passes through or does not pass through the first resistor 34 (R13), thereby causing the resistance value to ground output by the output end 60 to change.

[0030] According to the detection circuit 100 of the present embodiment, the detection circuit 100 electrically connects a plurality of detection terminals 20 to the chip 10, and a plurality of switch units 30 to the chip 10. Since each switch unit 30 includes a first MOS tube 31 (Q3), a second MOS tube 32 (Q4) and a third MOS tube 33 (Q5), and the second MOS tube 32 (Q4) and the third MOS tube 33 (Q5) are connected in parallel with a first resistor 34 (R13), the chip 10 detects different protection states and turns off, and the output terminal 60 outputs different resistance values ​​for the charger or tool control board to flexibly detect and respond to different states of the battery pack. The specific method is, for example, the gate of the first MOS tube 31 (Q3) (the gate is a control terminal, which controls the current flow between the source and the drain. In the first MOS tube 31 (Q3), the first MOS tube 31 can be regarded as an electrical switch. When a positive voltage is applied between the gate and the source of the first MOS tube 31, its switch is turned on. When turned on, the current can flow from the drain to the source through the switch.

[0031] It can be understood that the chip 10 includes a first output pin, the switch unit 30 includes a first switch unit 30, the first output pin is electrically connected to the first switch unit 30 through a transistor 50 (Q2), and the transistor 50 (Q2) is a PNP transistor. The first output pin here outputs an overcharge signal, the base of the transistor 50 (Q2) receives the overcharge signal from the first output pin of the chip 10, its collector is connected to the gate of the first MOS tube 31 (Q3) of the first switch unit 30, and the emitter is connected to the positive electrode of the battery. Using the transistor 50 (Q2) as an intermediary, rapid control of the first MOS tube 31 (Q3) can be achieved, which means that when the battery is overcharged or the overcharge temperature is high, the circuit can respond quickly and start the protection measures in time to avoid damage to the battery. At the same time, the risk of battery damage caused by overcharging is avoided, and the safety of the entire system is improved.

[0032] It can be understood that, based on the above embodiment, the chip 10 further includes a plurality of output pins, and the plurality of output pins are connected to the switch units 30 in a one-to-one correspondence. By respectively controlling the plurality of output pins to control different switch units 30, such as the first switch unit (having the first MOS tube 31 (Q3)), the second switch unit (having the second MOS tube 32 (Q4)) and the third switch unit (having the third MOS tube 33), the chip 10 can manage the charging and discharging process of the battery in a more refined and personalized manner, allowing the current flow direction of each battery cell or circuit part to be independently controlled, thereby improving the flexibility and efficiency of the charging and discharging process.

[0033] It is understandable that the detection end 20 is connected to a thermistor 40, which is used to detect the temperature of the battery. The thermistor 40 is electrically connected to one or more input pins of the chip 10 for real-time monitoring of the temperature change of the battery. The resistance of the thermistor 40 changes with temperature, and this change is converted into a temperature reading by the chip 10. According to the temperature state of the battery, the chip 10 can adjust the charge and discharge strategy and activate the corresponding protection mechanism. By monitoring the battery temperature in real time, this embodiment can take timely measures when the battery temperature is too high or too low, such as adjusting the charge and discharge rate or directly cutting off the charge and discharge path, to prevent battery damage caused by abnormal temperature.

[0034] It is understandable that the detection terminal 20 is connected to the positive or negative pole of the battery, respectively. These detection terminals 20 are connected to the positive and negative poles of the battery, respectively, and possible other intermediate nodes (for the case of multiple battery cells connected in series), so that the voltage of each battery cell can be accurately measured. In addition, appropriate isolation and protection circuits (such as isolation amplifiers, voltage dividers, overvoltage protection circuits, etc.) can be introduced between the detection terminal 20 and the chip 10 to ensure safe transmission and accurate reading of signals while avoiding potential damage to the battery cell or chip 10. By connecting the detection terminals 20 of the positive and negative poles of the battery, respectively, the circuit can more accurately monitor the voltage and charging state of the battery, provide more comprehensive battery information, and help implement more effective battery management strategies.

[0035] It is understandable that a second resistor 35 (Ra, which is a variable resistor) is connected between the output terminal 60 and the switch unit 30. The second resistor 35 (Ra) selects different resistance values ​​according to the different capacities of the batteries during production and assembly. Specifically, the resistance values ​​of the second resistor 35 (Ra) of different sizes can be selected according to the required battery pack capacity during production. The charger or tool control board can more accurately control the charge and discharge current according to the resistance value of the second resistor 35 to avoid overcharging or over-discharging of the battery, thereby optimizing the charge and discharge process and improving the battery efficiency and cycle life.

[0036] It is understandable that the output terminal 60 is connected to a ground wire. In the detection circuit 100 of the battery protection board, by grounding the output terminal 60, it can be ensured that the entire detection circuit 100 system has a common potential reference point. This configuration helps to reduce ground noise in the detection circuit 100 and improve the stability and accuracy of the signal. Grounding the output terminal 60 helps to stabilize the voltage level in the detection circuit 100, especially when multiple detection terminals 20 and switch units 30 are working, which can effectively reduce the voltage fluctuations and interference caused by the complexity of the detection circuit 100, thereby improving the overall performance and reliability of the detection circuit 100. By providing a stable ground potential reference for the detection circuit 100, the noise and interference of the detection circuit 100 are reduced, ensuring that the signal transmission from the detection terminal 20 to the output terminal 60 is more stable and reliable.

[0037] It is understandable that the chip 10 is connected to a ground line. In the detection circuit 100 of the battery protection board, the design includes a dedicated output pin, which is directly connected to the common ground line of the detection circuit 100. Such a configuration ensures that the chip 10 can process the battery monitoring signal based on a stable and consistent potential reference. By grounding a pin of the chip 10, the power management and signal processing modules inside the chip 10 can use this stable ground potential reference, thereby improving the accuracy of signal processing and the overall stability of the system. This configuration helps to reduce errors caused by potential fluctuations and optimize the performance of the detection circuit 100.

[0038] In some embodiments, the switch unit 30 includes three, namely, a first switch unit (having a first MOS tube 31 (Q3)), a second switch unit (having a second MOS tube 32 (Q4)) and a third switch unit (having a third MOS tube 33 (Q5)), and the detection end 20 includes a first detection end, a second detection end, a third detection end, a fourth detection end and a fifth detection end, and these five detection ends 20 are specifically used to detect overcharge, overdischarge and over-high charging temperature of five groups of batteries. When overcharge, overdischarge and over-high charging temperature or over-high discharging temperature occur. Through the first switch unit (having a first MOS tube 31 (Q3)), the second switch unit (having a second MOS tube 32 (Q4)) and the third switch unit (having a third MOS tube 33 (Q5)), and the second MOS tube 32 (Q4) and the third MOS tube 33 (Q5) are connected in parallel with a first resistor 34 (R13), these switch units 30 enable the battery protection board to accurately monitor and respond to the above four key battery states through their unique configuration. The first MOS tube 31 (Q3) of the first switch unit, the second MOS tube 32 (Q4) of the second switch unit, and the third MOS tube 33 (Q5) of the third switch unit are controlled through the output pin of the chip 10. The second switch unit and the third switch unit are both used to judge the overcharge state or the overcharge temperature state, while the third switch unit is used to judge the over-discharge and over-discharge temperature state. When the battery is overcharged, over-discharged, or the charging temperature is too high, or the discharging temperature is too high, the corresponding detection end 20 (including the detection end 20 for detecting voltage and the detection end 20 connected to the thermistor 40 for detecting temperature) will detect this state and send a signal to the chip 10 through its corresponding pin. The chip 10 controls the conduction and cutoff of the corresponding first MOS tube 31 (Q3), the second MOS tube 32 (Q4), and the third MOS tube 33 (Q5) according to the received signal. By monitoring the overcharge and over-discharge of the battery through a dedicated detection terminal 20 and the over-high charging temperature and over-high discharging temperature states connected to the thermistor 40, this solution can accurately identify the key safety risks of the battery and provide reliable data support for battery protection.

[0039] In this embodiment, the working principle of the detection circuit 100 is that, first, the detection end 20 monitors the voltage of the battery in real time and the detection end 20 (the detection end connected to the thermistor 40) monitors the battery temperature and other parameters in real time, and converts this information into an electrical signal and sends it to the chip 10. Secondly, the chip 10 receives the signal from the detection end 20 and determines whether the battery state is normal according to the preset threshold and logic. For example, if the battery temperature exceeds the safety threshold, the chip 10 will identify the state of excessive charging temperature. Afterwards, once an abnormal battery state is detected (such as overcharge, overdischarge or overcharge temperature, overdischarge temperature is too high), the chip 10 performs an action by controlling the first MOS tube 31 (Q3) of the corresponding first switch unit, the second MOS tube 32 (Q4) of the second switch unit, and the third MOS tube 33 (Q5) of the third switch unit. For example, the second MOS transistor 32 (Q4) and the third MOS transistor 33 (Q5) are turned off, and current passes through the first resistor 34 (R13) connected in parallel with the second MOS transistor 32 (Q4) and the third MOS transistor 33 (Q5). The first resistor 34 (R13) performs voltage division, thereby causing the voltage of the output terminal 60 to change.

[0040] In a specific embodiment, Figure 1As shown, when the detection signals of the detection terminals are normal, the charger or tool control board inputs a 5V voltage through the output terminal 60 (P1), and the current flows through the second resistor 35 (Ra) (the resistance of the second resistor 35 (Ra) is determined by the capacity of the battery pack) to the third MOS tube 33 (Q5) of the third switch unit, then to the second MOS tube 32 (Q4) of the second switch unit, and then to the first MOS tube 31 (Q3) of the first switch unit, and then flows into the ground terminal to form a loop. The PCDR pin (pin 16) and NCDR pin (pin 15) of the chip 10 are both overcharge signal and overcharge temperature driving pins. When the chip 10 detects that any group of cells reaches the overcharge voltage threshold or the cell temperature reaches the protection value, the 16 pin will drive the transistor 50 (Q2) to cut off the third MOS tube 33 (Q5) of the third switch unit, and the 15 pin will drive the second MOS tube 32 (Q4) of the second switch unit to cut off. Assuming that the charger detects the output terminal 60 (P1 terminal) signal at this time, the charger inputs a 5V voltage. Due to the cut-off of the second MOS tube 32 (Q4) and the third MOS tube 33 (Q5), the current passes through the second resistor 35 (Ra) (the resistance value is determined by the battery pack capacity) and the first resistor 34 (R13), and then passes through the first MOS tube 31 (Q3) of the first switch unit and flows into the ground terminal. The first resistor 34 (R13) and the second resistor 35 (Ra) are connected in series to generate a voltage drop (voltage division). The charger samples different voltage changes and performs corresponding actions. The NDDR pin (pin 13) of chip 10 is an over-discharge signal and over-discharge temperature driving pin, which is connected to the first MOS tube 31 (Q3) of the first switch unit. As long as it is detected that any group of battery cells reaches the over-discharge voltage threshold or the over-discharge temperature protection value, the first MOS tube 31 (Q3) is cut off and the circuit is disconnected. At this time, the output terminal 60 is suspended, its resistance is infinite, and the voltage of the output terminal 60 approaches 5V. When the tool control board samples this signal, it executes the corresponding action.

[0041] In a specific embodiment, the VTC pin (pin 9) and the VTD pin (pin 10) of the chip 10 detect the battery cell temperature signal, including the overcharge temperature and the overdischarge temperature.

[0042] It is understandable that the external charger can select the charging current size according to the output signal of the output terminal 60 (P1) and collect the overcharge and overcharge temperature signals of the battery pack to perform protection. The tool control board can understand the capacity of the battery pack according to the output signal of the output terminal 60 (P1) to select the appropriate discharge current size and collect the over-discharge and over-discharge temperature signals of the battery pack to perform protection.

[0043] This embodiment also proposes a battery management system, including the above detection circuit 100. The battery management system integrates a highly integrated detection circuit 100, which is specially designed for real-time monitoring and protection of battery packs, and ensures that the battery operates in a safe and efficient state by intelligently processing detection signals.

[0044] This embodiment also provides a battery pack, including the above-mentioned battery management system.

[0045] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A detection circuit for a battery protection board, characterized in that: include: chip; A plurality of detection terminals, wherein the plurality of detection terminals are electrically connected to the chip; A plurality of switch units, wherein the plurality of switch units are connected in series with each other, the plurality of switch units are electrically connected to the chip, the switch units include MOS tubes, and some of the switch units are connected in parallel with resistors; An output end is electrically connected to the plurality of switch units.

2. The detection circuit of the battery protection board according to claim 1, characterized in that: The chip includes a first output pin, the switch unit includes a first switch unit, and the first output pin is electrically connected to the first switch unit through a transistor.

3. The detection circuit of the battery protection board according to claim 2, characterized in that: The chip further includes a plurality of output pins, and the plurality of output pins are connected to the switch units in a one-to-one correspondence.

4. The detection circuit of the battery protection board according to claim 1, characterized in that: The detection end is connected to a thermistor, and the thermistor is used to detect the temperature of the battery.

5. The detection circuit of the battery protection board according to claim 1, characterized in that: The detection ends are respectively connected to the positive electrode or the negative electrode of the battery.

6. The detection circuit of the battery protection board according to claim 1, characterized in that: A variable resistor is connected between the output end and the switch unit.

7. The detection circuit of the battery protection board according to claim 1, characterized in that: The output end is connected with a ground wire.

8. The detection circuit of the battery protection board according to claim 1, characterized in that: The chip is connected to a ground line.

9. A battery management system, characterized in that: A detection circuit comprising a battery protection board according to any one of claims 1 to 8.

10. A battery pack, characterized in that: Comprising a battery management system according to claim 9.

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