A disconnection protection circuit based on split battery pack

Abstract

The present invention relates to the technical field of battery packs, and in particular to a disconnection protection circuit based on a split battery pack, comprising a first battery, a second battery, a positive output port, a negative output port, a diode AD46, a diode AD47, a diode AD49, a diode AD50, a resistor AR35, a resistor AR36, a resistor AR60, a capacitor AC53, a trigger element, a first switch module, a MOS tube MD1, a second switch module and a MOS tube MC1; the trigger element comprises a control unit and a switch unit. In the present invention, when the series line between the first battery and the second battery is disconnected during the charging process and the discharging process, the MOS tube MC1 and the MOS tube MD1 can be turned off in time, so that the battery pack stops charging or discharging, and damage to each device can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of battery packs, and in particular to a disconnection protection circuit based on a split battery pack. Background Art

[0002] In today's science and technology and energy fields, lithium batteries are widely used in many industries and equipment due to their many advantages such as high energy density and long cycle life. From electric vehicles to various portable electronic devices, their market demand has shown a sustained and rapid growth trend. With the continuous expansion of application scenarios and the increasing requirements for performance such as battery life, the demand for large-capacity battery cells has become more urgent.

[0003] In the actual production and application process, when some battery cells are too large, battery pack manufacturers often adopt a sub-packaging strategy to overcome difficulties in transportation and other links. For example, a common 48V battery pack is split into two 24V battery packs, and a protection board is installed on the negative battery pack. This method does have significant advantages. It can effectively reduce the overall weight and transportation volume, thus greatly facilitating long-distance transportation and deployment between different sites.

[0004] After the battery pack arrives at the destination, the two 24V battery packs are assembled and connected together with the help of external series wires to restore the working voltage to 48V. However, this method of assembly relying on external series wires has serious drawbacks. Due to the uneven technical level of the installers, many problems are prone to occur during the actual installation operation. On the one hand, the series wire may be too long. The excessively long wire will significantly increase the internal resistance of the line. During the charging and discharging process, the excessive internal resistance will cause additional heat loss, reducing the overall efficiency of the battery system. At the same time, it will also affect the voltage consistency of the battery pack, causing abnormal fluctuations in the voltage of a battery in series, thereby affecting the performance and safety of the entire battery pack. On the other hand, what is more serious is that improper installation may cause poor contact problems and even wire shedding. When the wire falls off, due to the effect of the equivalent circuit composed of the charger, load, etc., a negative pressure will be generated at the detection foot of the battery that has fallen off. The generation of this negative pressure is very likely to damage the protection board of the battery pack. The protection board is a key component to ensure the safe operation of the battery. Once damaged, it may cause the battery pack to lose basic protection functions such as overcharging, over-discharging, and short circuit, and then cause more serious safety accidents such as battery overheating, fire, or even explosion, posing a huge threat to the safety of life and property as well as the surrounding environment. Summary of the invention

[0005] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and provide a line break protection circuit based on a split battery pack.

[0006] The object of the present invention is achieved through the following technical solutions: A disconnection protection circuit based on a split battery pack, comprising a first battery, a second battery, a positive output port, a negative output port, a diode AD46, a diode AD47, a diode AD49, a diode AD50, a resistor AR35, a resistor AR36, a resistor AR60, a capacitor AC53, a trigger element, a first switch module, a MOS tube MD1, a second switch module and a MOS tube MC1;

[0007] The trigger element includes a control part and a switch part;

[0008] A series line is provided between the positive electrode of the first battery and the negative electrode of the second battery; the positive electrode of the diode AD46 and the negative electrode of the diode AD49 are respectively connected to the negative electrode of the second battery; the positive electrode of the diode AD47 and the negative electrode of the diode AD50 are respectively connected to the positive electrode of the first battery; the negative electrode of the diode AD46 and the negative electrode of the diode AD47 are respectively connected to one end of the control unit through the resistor AR35 and the resistor AR36; the positive electrode of the diode AD49 and the positive electrode of the diode AD50 are respectively connected to the other end of the control unit; the resistor AR60 is provided between the two ends of the control unit; the resistor AR60 is connected in parallel with the capacitor AC53;

[0009] One end of the switch part is grounded; the other end of the switch part is connected to the control end of the MOS tube MD1 through the first switch module; the other end of the switch part is connected to the control end of the MOS tube MC1 through the second switch module; the positive output port, the switch end of the MOS tube MD1, the switch end of the MOS tube MC1 and the negative output port are connected in series.

[0010] The present invention is further configured that the first switch module includes a transistor AQ12, a transistor AQ13 and a transistor AQ9;

[0011] The other end of the switch part is connected to the base of the transistor AQ12; the emitter of the transistor AQ12 is connected to the power supply; the collector of the transistor AQ12 is connected to the base of the transistor AQ13; the emitter of the transistor AQ13 is grounded; the emitter of the transistor AQ13 is connected to the base of the transistor AQ9; the collector of the transistor AQ9 is grounded; the emitter of the transistor AQ9 is connected to the control end of the MOS tube MD1.

[0012] The present invention is further configured as follows: the first switch module also includes a transistor AQ6 and a transistor AQ8; the collector of the transistor AQ6 and the collector of the transistor AQ8 are respectively connected to the power supply; the emitter of the transistor AQ6 is connected to the collector of the transistor AQ8; the emitter of the transistor AQ8 is connected to the control end of the MOS tube MD1; the base of the transistor AQ8 is connected to the base of the transistor AQ9.

[0013] The present invention is further configured as follows: the first switch module also includes a control port, a diode AD12, a diode AD13 and a resistor AR80; the control port is connected to the cathode of the diode AD12 through the resistor AR80; the anode of the diode AD12 is connected to the base of the transistor AQ6; the anode of the diode AD12 is connected to the cathode of the diode AD13; the anode of the diode AD13 is connected to the base of the transistor AQ8.

[0014] The present invention is further configured such that the line break protection circuit based on the split battery pack also includes an MCU controller; the other end of the switch part and the control port are respectively connected to the MCU controller.

[0015] The present invention is further configured as follows: the second switch module includes a transistor AQ7, a transistor AQ5 and a transistor AQ4; the base of the transistor AQ7 is connected to the other end of the switch part; the emitter of the transistor AQ7 is grounded; the collector of the transistor AQ7 is connected to the base of the transistor AQ5; the collector of the transistor AQ5 is connected to a power supply; the collector of the transistor AQ5 is connected to the collector of the transistor AQ4; the base of the transistor AQ4 is connected to the emitter of the transistor AQ5; the emitter of the transistor AQ4 is connected to the power supply; the collector of the transistor AQ4 is connected to the control end of the MOS tube MC1.

[0016] The present invention is further configured such that the second switch module also includes a transistor AQ11 and a transistor AQ10; the collector of the transistor AQ10 is grounded; the base of the transistor AQ10 is connected to the collector of the transistor AQ4; the emitter of the transistor AQ10 is connected to the base of the transistor AQ11; the collector of the transistor AQ11 is grounded; and the emitter of the transistor AQ11 is connected to the control end of the MOS tube MC1.

[0017] The present invention is further configured such that the positive output port is connected to the source of the MOS tube MD1; the drain of the MOS tube MD1 is connected to the drain of the MOS tube MC1; and the source of the MOS tube MC1 is connected to the negative output port.

[0018] The present invention is further configured such that the trigger element is an optical coupler AU3.

[0019] Beneficial effects of the present invention: During the charging process and the discharging process, when the series line between the first battery and the second battery is disconnected, the MOS tube MC1 and the MOS tube MD1 can be turned off in time, so that the battery pack stops charging or discharging, which can avoid damage to various components. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0021] Figure 1 It is a circuit schematic diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of the battery pack when it is charging;

[0023] Figure 3 It is a schematic diagram of the battery pack when it is discharged;

[0024] Among them: 1. first battery; 2. second battery; 3. series line; 41. positive output port; 42. negative output port; 51. control unit; 52. switch unit; 6. control port. DETAILED DESCRIPTION

[0025] The present invention is further described in conjunction with the following examples.

[0026] Depend on Figures 1 to 3It can be seen that the disconnection protection circuit based on the split battery pack described in this embodiment includes a first battery, a second battery, a positive output port, a negative output port, a diode AD46, a diode AD47, a diode AD49, a diode AD50, a resistor AR35, a resistor AR36, a resistor AR60, a capacitor AC53, a trigger element, a first switch module, a MOS tube MD1, a second switch module and a MOS tube MC1; the trigger element includes a control unit and a switch unit; a series line is provided between the positive electrode of the first battery and the negative electrode of the second battery; the positive electrode of the diode AD46 and the negative electrode of the diode AD49 are respectively connected to the negative electrode of the second battery; the positive electrode of the diode AD47 and the negative electrode of the diode AD50 are respectively connected to the first The positive electrode of the battery is connected; the negative electrode of the diode AD46 and the negative electrode of the diode AD47 are connected to one end of the control unit through the resistor AR35 and the resistor AR36 respectively; the positive electrode of the diode AD49 and the positive electrode of the diode AD50 are connected to the other end of the control unit respectively; the resistor AR60 is arranged between the two ends of the control unit; the resistor AR60 is connected in parallel with the capacitor AC53; one end of the switch unit is grounded; the other end of the switch unit is connected to the control end of the MOS tube MD1 through the first switch module; the other end of the switch unit is connected to the control end of the MOS tube MC1 through the second switch module; the positive output port, the switch end of the MOS tube MD1, the switch end of the MOS tube MC1 and the negative output port are connected in series. In the disconnection protection circuit based on the split battery pack described in this embodiment, the positive output port is connected to the source of the MOS tube MD1; the drain of the MOS tube MD1 is connected to the drain of the MOS tube MC1; the source of the MOS tube MC1 is connected to the negative output port.

[0027] Specifically, in the disconnection protection circuit based on the split battery pack described in this embodiment, during normal use, the voltage difference between the first battery and the second battery will not exceed 4.2V.

[0028] When the battery pack is in discharge, the positive output port and the negative output port are connected to the load respectively. If the series line is disconnected, the positive electrode of the second battery will be connected in series to the negative electrode of the first battery through the load, which is equivalent to the voltage of the BC7 port being higher than the voltage of the BC8 port. If the voltage of the BC7 port is higher than the voltage of the BC8 port by more than a certain value, the switch part of the trigger element is turned on, and the MOS tube MD1 is disconnected through the first switch module, and the MOS tube MC1 is disconnected through the second switch module, so that the positive output port is disconnected from the negative output port;

[0029] In addition, when the battery pack is being charged, the positive output port and the negative output port are connected to the charger respectively, and the charging current flows from the BC8 port to the BC7 port. When the series line is disconnected, the voltage of the BC8 port is higher than the voltage of the BC7 port. Due to the voltage division of the resistors AR35, AR36 and AR60, the voltage difference between the BC8 port and the BC7 port is lower than 4.2V and will not operate. When the voltage difference between the BC8 port and the BC7 port is higher than the set value, the switch part of the trigger element is turned on, and the MOS tube MD1 is disconnected by the first switch module, and the MOS tube MC1 is disconnected by the second switch module, thereby disconnecting the positive output port from the negative output port.

[0030] This embodiment uses MOS transistor MC1 and MOS transistor MD1 as switch elements between the positive output port and the negative output port, which has the advantages of high input impedance, fast switching speed and strong stability. However, the MOS transistor has a parasitic diode. This embodiment sets two MOS transistors in series to ensure that during the charging and discharging process, after the series line is disconnected, the positive output port and the negative output port are disconnected.

[0031] In addition, in this embodiment, the values ​​of resistors AR35, AR36 and AR60 can be adjusted to match the voltage value to be triggered; the action delay can be adjusted to avoid false triggering of protection by adjusting the value of capacitor AC53.

[0032] This embodiment can promptly shut down the MOS tube MC1 and the MOS tube MD1 during the charging and discharging process when the series line between the first battery and the second battery is disconnected, thereby stopping the charging or discharging of the battery pack and avoiding damage to various components.

[0033] The present embodiment describes a line break protection circuit based on a split battery pack, wherein the first switch module includes a transistor AQ12, a transistor AQ13 and a transistor AQ9; the other end of the switch unit is connected to the base of the transistor AQ12; the emitter of the transistor AQ12 is connected to a power supply; the collector of the transistor AQ12 is connected to the base of the transistor AQ13; the emitter of the transistor AQ13 is grounded; the emitter of the transistor AQ13 is connected to the base of the transistor AQ9; the collector of the transistor AQ9 is grounded; and the emitter of the transistor AQ9 is connected to the control end of the MOS tube MD1. In the present embodiment, a line break protection circuit based on a split battery pack is described, wherein the first switch module also includes a transistor AQ6 and a transistor AQ8; the collector of the transistor AQ6 and the collector of the transistor AQ8 are respectively connected to a power supply; the emitter of the transistor AQ6 is connected to the collector of the transistor AQ8; the emitter of the transistor AQ8 is connected to the control end of the MOS tube MD1; and the base of the transistor AQ8 is connected to the base of the transistor AQ9.

[0034] Specifically, in the line break protection circuit based on the split battery pack described in this embodiment, when the battery pack is in discharge, the positive output port and the negative output port are respectively connected to the load. If the series line is disconnected, the positive electrode of the second battery will be connected in series to the negative electrode of the first battery through the load, which is equivalent to the voltage of the BC7 port being higher than the voltage of the BC8 port. If the voltage of the BC7 port is higher than the voltage of the BC8 port by more than a certain value, the switch part of the trigger element is turned on, thereby turning on the transistor AQ12, the transistor AQ13 and the transistor AQ9 in turn, so that the control end of the MOS tube MD1 loses voltage and the switch end of the MOS tube MD1 is disconnected.

[0035] When the battery pack is being charged, the positive output port and the negative output port are connected to the charger respectively, and the charging current flows from the BC8 port to the BC7 port. When the series line is disconnected, the voltage of the BC8 port is higher than the voltage of the BC7 port. Due to the voltage division of the resistors AR35, AR36 and AR60, the voltage difference between the BC8 port and the BC7 port is lower than 4.2V and will not act. When the voltage difference between the BC8 port and the BC7 port is higher than the set value, the switch part of the trigger element is turned on, thereby turning on the transistor AQ12, the transistor AQ13 and the transistor AQ9 in turn, so that the control end of the discharge switch tube MD1 loses voltage and the switch end of the MOS tube MD1 is disconnected.

[0036] The present embodiment describes a disconnection protection circuit based on a split battery pack, wherein the first switch module further includes a control port, a diode AD12, a diode AD13, and a resistor AR80; the control port is connected to the cathode of the diode AD12 through the resistor AR80; the anode of the diode AD12 is connected to the base of the transistor AQ6; the anode of the diode AD12 is connected to the cathode of the diode AD13; the anode of the diode AD13 is connected to the base of the transistor AQ8. Through the above settings, the user can send a signal to the control port through the MUC controller, thereby directly disconnecting the switch end of the MOS tube MD1, so that the positive output port is disconnected from the negative output port.

[0037] The present embodiment describes a disconnection protection circuit based on a split battery pack, and the disconnection protection circuit based on a split battery pack further includes an MCU controller; the other end of the switch part and the control port are respectively connected to the MCU controller; the MCU controller is not shown in the figure. When the switch part of the trigger element is turned on, the MCU controller can sense the signal, thereby effectively detecting the disconnection of the series line.

[0038] The present embodiment describes a line-break protection circuit based on a split battery pack, wherein the second switch module includes a transistor AQ7, a transistor AQ5 and a transistor AQ4; the base of the transistor AQ7 is connected to the other end of the switch unit; the emitter of the transistor AQ7 is grounded; the collector of the transistor AQ7 is connected to the base of the transistor AQ5; the collector of the transistor AQ5 is connected to a power supply; the collector of the transistor AQ5 is connected to the collector of the transistor AQ4; the base of the transistor AQ4 is connected to the emitter of the transistor AQ5; the emitter of the transistor AQ4 is connected to a power supply; the collector of the transistor AQ4 is connected to the control end of the MOS tube MC1. In the present embodiment, a line break protection circuit based on a split battery pack is described, wherein the second switch module further includes a transistor AQ11 and a transistor AQ10; the collector of the transistor AQ10 is grounded; the base of the transistor AQ10 is connected to the collector of the transistor AQ4; the emitter of the transistor AQ10 is connected to the base of the transistor AQ11; the collector of the transistor AQ11 is grounded; and the emitter of the transistor AQ11 is connected to the control end of the MOS tube MC1.

[0039] Specifically, in the line break protection circuit based on the split battery pack described in this embodiment, when the battery pack is in discharge, the positive output port and the negative output port are respectively connected to the load. If the series line is disconnected, the positive electrode of the second battery will be connected in series to the negative electrode of the first battery through the load, which is equivalent to the voltage of the BC7 port being higher than the voltage of the BC8 port. If the voltage of the BC7 port is higher than the voltage of the BC8 port by more than a certain value, the switch part of the trigger element is turned on, thereby turning on the transistor AQ7, the transistor AQ5 and the transistor AQ4 in turn, so that the control end of the MOS tube MC1 loses voltage and the switch end of the MOS tube MC1 is disconnected.

[0040] When the battery pack is being charged, the positive output port and the negative output port are connected to the charger respectively, and the charging current flows from the BC8 port to the BC7 port. When the series line is disconnected, the voltage of the BC8 port is higher than the voltage of the BC7 port. Due to the voltage division of the resistors AR35, AR36 and AR60, the voltage difference between the BC8 port and the BC7 port is lower than 4.2V and will not operate. When the voltage difference between the BC8 port and the BC7 port is higher than the set value, the switch part of the trigger element is turned on, thereby turning on the transistor AQ7, the transistor AQ5 and the transistor AQ4 in turn, so that the control end of the MOS tube MC1 loses voltage and the switch end of the MOS tube MC1 is disconnected.

[0041] In the disconnection protection circuit based on the split battery pack described in this embodiment, the trigger element is the optical coupler AU3. The above arrangement makes the overall structure stable and reliable.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A disconnection protection circuit based on a split battery pack, characterized in that: It includes a first battery, a second battery, a positive output port, a negative output port, a diode AD46, a diode AD47, a diode AD49, a diode AD50, a resistor AR35, a resistor AR36, a resistor AR60, a capacitor AC53, a trigger element, a first switch module, a MOS tube MD1, a second switch module and a MOS tube MC1; The trigger element includes a control part and a switch part; A series line is provided between the positive electrode of the first battery and the negative electrode of the second battery; the positive electrode of the diode AD46 and the negative electrode of the diode AD49 are respectively connected to the negative electrode of the second battery; the positive electrode of the diode AD47 and the negative electrode of the diode AD50 are respectively connected to the positive electrode of the first battery; the negative electrode of the diode AD46 and the negative electrode of the diode AD47 are respectively connected to one end of the control unit through the resistor AR35 and the resistor AR36; the positive electrode of the diode AD49 and the positive electrode of the diode AD50 are respectively connected to the other end of the control unit; the resistor AR60 is provided between the two ends of the control unit; the resistor AR60 is connected in parallel with the capacitor AC53; One end of the switch part is grounded; the other end of the switch part is connected to the control end of the MOS tube MD1 through the first switch module; the other end of the switch part is connected to the control end of the MOS tube MC1 through the second switch module; the positive output port, the switch end of the MOS tube MD1, the switch end of the MOS tube MC1 and the negative output port are connected in series.

2. According to claim 1, a disconnection protection circuit based on a split battery pack is characterized in that: The first switch module includes a transistor AQ12, a transistor AQ13 and a transistor AQ9; The other end of the switch part is connected to the base of the transistor AQ12; the emitter of the transistor AQ12 is connected to the power supply; the collector of the transistor AQ12 is connected to the base of the transistor AQ13; the emitter of the transistor AQ13 is grounded; the emitter of the transistor AQ13 is connected to the base of the transistor AQ9; the collector of the transistor AQ9 is grounded; the emitter of the transistor AQ9 is connected to the control end of the MOS tube MD1.

3. According to claim 2, a disconnection protection circuit based on a split battery pack is characterized in that: The first switch module also includes a transistor AQ6 and a transistor AQ8; the collector of the transistor AQ6 and the collector of the transistor AQ8 are respectively connected to the power supply; the emitter of the transistor AQ6 is connected to the collector of the transistor AQ8; the emitter of the transistor AQ8 is connected to the control end of the MOS tube MD1; the base of the transistor AQ8 is connected to the base of the transistor AQ9.

4. A disconnection protection circuit based on a split battery pack according to claim 3, characterized in that: The first switch module also includes a control port, a diode AD12, a diode AD13 and a resistor AR80; the control port is connected to the cathode of the diode AD12 through the resistor AR80; the anode of the diode AD12 is connected to the base of the transistor AQ6; the anode of the diode AD12 is connected to the cathode of the diode AD13; the anode of the diode AD13 is connected to the base of the transistor AQ8.

5. A disconnection protection circuit based on a split battery pack according to claim 4, characterized in that: The disconnection protection circuit based on the split battery pack also includes an MCU controller; the other end of the switch part and the control port are respectively connected to the MCU controller.

6. A disconnection protection circuit based on a split battery pack according to claim 1, characterized in that: The second switch module includes transistor AQ7, transistor AQ5 and transistor AQ4; the base of the transistor AQ7 is connected to the other end of the switch part; the emitter of the transistor AQ7 is grounded; the collector of the transistor AQ7 is connected to the base of the transistor AQ5; the collector of the transistor AQ5 is connected to the power supply; the collector of the transistor AQ5 is connected to the collector of the transistor AQ4; the base of the transistor AQ4 is connected to the emitter of the transistor AQ5; the emitter of the transistor AQ4 is connected to the power supply; the collector of the transistor AQ4 is connected to the control end of the MOS tube MC1.

7. A disconnection protection circuit based on a split battery pack according to claim 6, characterized in that: The second switch module also includes a transistor AQ11 and a transistor AQ10; the collector of the transistor AQ10 is grounded; the base of the transistor AQ10 is connected to the collector of the transistor AQ4; the emitter of the transistor AQ10 is connected to the base of the transistor AQ11; the collector of the transistor AQ11 is grounded; and the emitter of the transistor AQ11 is connected to the control end of the MOS tube MC1.

8. The disconnection protection circuit based on a split battery pack according to claim 1, characterized in that: The positive output port is connected to the source of the MOS transistor MD1; the drain of the MOS transistor MD1 is connected to the drain of the MOS transistor MC1; the source of the MOS transistor MC1 is connected to the negative output port.

9. The disconnection protection circuit based on a split battery pack according to claim 1, characterized in that: The trigger element is an optical coupler AU3.

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