Battery pack open circuit detection circuit

Abstract

The utility model relates to the technical field of battery packs, in particular to a battery pack circuit break detection circuit, which comprises 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 and a charging and discharging switch tube MD1. The trigger element comprises a control part and a switch part. According to the utility model, in the charging process and the discharging process, after the series connection line between the first battery and the second battery is disconnected, the charging and discharging switch tube MD1 can be closed in time, so that the battery pack stops charging or discharging, and the damage of each device can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of battery pack technology, and specifically to a battery pack open circuit detection circuit. Background Technology

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

[0003] In actual production and application, when some battery cells are too large, battery pack manufacturers often adopt a repackaging strategy to overcome difficulties in transportation and other aspects. 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 allocation between different sites.

[0004] After the battery pack arrives at its destination, the two 24V battery packs are connected together using an external series cable to restore the operating voltage to 48V. However, this assembly method relying on an external series cable has serious drawbacks. Due to varying skill levels among installers, numerous problems can easily arise during actual installation. Firstly, the series cable may become excessively long. Excessive cable length significantly increases internal resistance, leading to additional heat loss during charging and discharging, reducing the overall efficiency of the battery system. It also affects voltage consistency, causing abnormal voltage fluctuations in any connected cell, thus impacting the overall performance and safety of the battery pack. Secondly, and more seriously, improper installation can cause poor contact or even cable detachment. When a cable detaches, the equivalent circuit formed by the charger and load creates a negative voltage at the detection pin of the detached cell. The generation of this negative pressure is very likely to damage the protection board of the battery pack. As a key component to ensure the safe operation of the battery, once the protection board is damaged, it may cause the battery pack to lose its basic protection functions such as overcharging, over-discharging, and short circuit, which may lead to more serious safety accidents such as battery overheating, fire or even explosion, posing a huge threat to the safety of people's lives and property and the surrounding environment. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing a battery pack open circuit detection circuit.

[0006] The purpose of this utility model is achieved through the following technical solution: a battery pack open circuit detection circuit, including a first battery, a second battery, a positive output port, a negative output port, diodes AD46, AD47, AD49, and AD50, resistors AR35, AR36, and AR60, a capacitor AC53, a trigger element, a first switch module, and a charge / discharge switch transistor MD1.

[0007] The triggering element includes a control unit and a switching unit;

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

[0009] One end of the switch is grounded; the other end of the switch is connected to the control terminal of the charge / discharge switch tube MD1 via the first switch module; the switch terminals of the charge / discharge switch tube MD1 are connected to the positive output port and the negative output port, respectively.

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

[0011] The other end of the switch is connected to the base of transistor AQ12; the emitter of transistor AQ12 is connected to the power supply; the collector of transistor AQ12 is connected to the base of transistor AQ13; the emitter of transistor AQ13 is grounded; the emitter of transistor AQ13 is connected to the base of transistor AQ9; the collector of transistor AQ9 is grounded; the emitter of transistor AQ9 is connected to the control terminal of charge / discharge switch MD1.

[0012] The present invention is further configured such that the first switching module further includes transistors AQ6 and AQ8; the collectors of transistors AQ6 and AQ8 are respectively connected to a power supply; the emitter of transistor AQ6 is connected to the collector of transistor AQ8; the emitter of transistor AQ8 is connected to the control terminal of charge / discharge switch MD1; and the base of transistor AQ8 is connected to the base of transistor AQ9.

[0013] The present invention is further configured such that the first switch module includes a control port, diode AD12, diode AD13, and resistor AR80; the control port is connected to the negative terminal of diode AD12 through resistor AR80; the positive terminal of diode AD12 is connected to the base of transistor AQ6; the positive terminal of diode AD12 is connected to the negative terminal of diode AD13; and the positive terminal of diode AD13 is connected to the base of transistor AQ8.

[0014] The present invention is further configured such that the battery pack open circuit detection circuit also includes an MCU controller; the other end of the switch and the control port are respectively connected to the MCU controller.

[0015] The present invention is further configured such that the triggering element is an optocoupler AU3.

[0016] The beneficial effects of this utility model are as follows: During the charging and discharging process, when the series line between the first battery and the second battery is broken, the charging and discharging switch MD1 can be turned off in time, thereby stopping the battery pack from charging or discharging and avoiding damage to various components. Attached Figure Description

[0017] The utility model will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present utility model. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0018] Figure 1 This is the circuit schematic diagram of this utility model;

[0019] Figure 2 This is a diagram illustrating the charging process of the battery pack.

[0020] Figure 3 This is a schematic diagram of the battery pack discharging.

[0021] 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 Implementation

[0022] The present invention will be further described in conjunction with the following embodiments.

[0023] Depend on Figures 1 to 3As can be seen, the battery pack open circuit detection circuit described in this embodiment includes a first battery 1, a second battery 2, a positive output port 41, a negative output port 42, diodes AD46, AD47, AD49, and AD50, resistors AR35, AR36, and AR60, a capacitor AC53, a trigger element, a first switch module, and a charge / discharge switch transistor MD1.

[0024] The triggering element includes a control unit 51 and a switch unit 52;

[0025] A series line 3 is provided between the positive terminal of the first battery 1 and the negative terminal of the second battery 2; the positive terminal of diode AD46 and the negative terminal of diode AD49 are respectively connected to the negative terminal of the second battery 2; the positive terminal of diode AD47 and the negative terminal of diode AD50 are respectively connected to the positive terminal of the first battery 1; the negative terminals of diode AD46 and diode AD47 are respectively connected to one end of the control unit 51 through resistors AR35 and AR36; the positive terminals of diode AD49 and diode AD50 are respectively connected to the other end of the control unit 51; resistor AR60 is disposed between the two ends of the control unit 51; resistor AR60 is connected in parallel with capacitor AC53;

[0026] One end of the switch section 52 is grounded; the other end of the switch section 52 is connected to the control terminal of the charge / discharge switch tube MD1 after passing through the first switch module; the switch terminal of the charge / discharge switch tube MD1 is connected to the positive output port 41 and the negative output port 42 respectively; wherein the positive output port 41 and the negative output port 42 are the positive electrode and the negative electrode of the entire battery pack, respectively.

[0027] Specifically, in the battery pack open circuit detection circuit described in this embodiment, the voltage difference between the first battery 1 and the second battery 2 will not exceed 4.2V during normal use.

[0028] When the battery pack is discharging, the positive output port 41 and the negative output port 42 are connected to the load respectively. If the series line 3 is disconnected, the positive terminal of the second battery 2 will be connected in series to the negative terminal of the first battery 1 through the load. This is equivalent to the voltage at port BC7 being higher than the voltage at port BC8. If the voltage at port BC7 is higher than the voltage at port BC8 by a certain value, the switching part 52 of the trigger element will be turned on, and the charge / discharge switch MD1 will be disconnected through the first switching module. The charge / discharge switch MD1 can be a transistor.

[0029] Additionally, when the battery pack is charging, the positive output port 41 and the negative output port 42 are connected to the charger respectively. The charging current flows from the BC8 port to the BC7 port. When the series line 3 is disconnected, the voltage at the BC8 port is higher than the voltage at the BC7 port. Due to the voltage division of resistors AR35, AR36 and AR60, the voltage difference between the BC8 port and the BC7 port is less than 4.2V and will not activate. When the voltage difference between the BC8 port and the BC7 port is higher than the set value, the switching part 52 of the trigger element is turned on, and the charging and discharging switch tube MD1 is disconnected through the first switching module.

[0030] In addition, this embodiment can match the required trigger voltage value by adjusting the values ​​of resistors AR35, AR36, and AR60; and adjust the action delay by adjusting the value of capacitor AC53 to avoid false triggering of the protection.

[0031] This embodiment can promptly shut down the charge / discharge switch MD1 when the series line 3 between the first battery 1 and the second battery 2 is disconnected during charging and discharging, thereby stopping the battery pack from charging or discharging and preventing damage to various components.

[0032] This embodiment describes a battery pack open circuit detection circuit. The first switching module includes transistors AQ12, AQ13, and AQ9. The other end of the switching unit 52 is connected to the base of transistor AQ12. The emitter of transistor AQ12 is connected to the power supply. The collector of transistor AQ12 is connected to the base of transistor AQ13. The emitter of transistor AQ13 is grounded. The emitter of transistor AQ13 is connected to the base of transistor AQ9. The collector of transistor AQ9 is grounded. The emitter of transistor AQ9 is connected to the control terminal of the charge / discharge switch MD1. The battery pack open circuit detection circuit described in this embodiment includes a first switching module that further comprises transistors AQ6 and AQ8; the collectors of transistors AQ6 and AQ8 are respectively connected to a power supply; the emitter of transistor AQ6 is connected to the collector of transistor AQ8; the emitter of transistor AQ8 is connected to the control terminal of charge / discharge switch MD1; and the base of transistor AQ8 is connected to the base of transistor AQ9.

[0033] Specifically, in the battery pack open circuit detection circuit described in this embodiment, when the battery pack is discharging, the positive output port 41 and the negative output port 42 are connected to the load respectively. If the series line 3 is disconnected, the positive terminal of the second battery 2 will be connected in series to the negative terminal of the first battery 1 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 a certain value, the switching part 52 of the trigger element will be turned on, thereby sequentially turning on the transistors AQ12, AQ13, and AQ9, thereby causing the control terminal of the discharge switch transistor MD1 to lose voltage and the switching terminal of the discharge switch transistor MD1 to be disconnected, so that the positive output port 41 and the negative output port 42 are disconnected.

[0034] When the battery pack is charging, the positive output port 41 and the negative output port 42 are connected to the charger respectively. The charging current flows from the BC8 port to the BC7 port. When the series line 3 is disconnected, the voltage of the BC8 port is higher than the voltage of the BC7 port. Due to the voltage division of resistors AR35, AR36 and AR60, the voltage difference between the BC8 port and the BC7 port is less than 4.2V and will not activate. When the voltage difference between the BC8 port and the BC7 port is higher than the set value, the switching part 52 of the trigger element is turned on, thereby turning on transistors AQ12, AQ13 and AQ9 in sequence. This causes the control terminal of the discharge switch MD1 to lose voltage, and the switching terminal of the discharge switch MD1 is turned off, so that the positive output port 41 and the negative output port 42 are disconnected.

[0035] This embodiment describes a battery pack open-circuit detection circuit. The first switching module further includes a control port 6, diodes AD12 and AD13, and a resistor AR80. The control port 6 is connected to the negative terminal of diode AD12 via resistor AR80. The positive terminal of diode AD12 is connected to the base of transistor AQ6. The positive terminal of diode AD12 is connected to the negative terminal of diode AD13. The positive terminal of diode AD13 is connected to the base of transistor AQ8. With this configuration, the user can send a signal to the control port 6 via the MUC controller, directly causing the switching terminal of the discharge switch MD1 to open, thus disconnecting the positive output port 41 from the negative output port 42.

[0036] This embodiment describes a battery pack open circuit detection circuit, which also includes an MCU controller. The other end of the switch 52 and the control port 6 are connected to the MCU controller; however, the MCU controller is not shown in the figure. When the switch 52 of the trigger element is turned on, the MCU controller can sense the signal, thereby effectively detecting the disconnection of the series wire 3.

[0037] The battery pack open circuit detection circuit described in this embodiment uses an optocoupler AU3 as the triggering element. This configuration ensures a stable and reliable overall structure.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A battery pack open-circuit detection circuit, characterized by: The first battery (1), the second battery (2), the positive output (41), the negative output (42), diode AD46, diode AD47, diode AD49, diode AD50, resistor AR35, resistor AR36, resistor AR60, capacitor AC53, a trigger element, a first switch module and charge-discharge switch tube MD1 are included. The trigger element includes a control part (51) and a switch part (52). The positive pole of the first battery (1) and the negative pole of the second battery (2) are provided with a series line (3); the positive pole of diode AD46 and the negative pole of diode AD49 are connected with the negative pole of the second battery (2) respectively; the positive pole of diode AD47 and the negative pole of diode AD50 are connected with the positive pole of the first battery (1) respectively; the negative pole of diode AD46 and the negative pole of diode AD47 are connected with one end of the control part (51) through resistor AR35 and resistor AR36 respectively; the positive pole of diode AD49 and the positive pole of diode AD50 are connected with the other end of the control part (51) respectively; the resistor AR60 is arranged between the two ends of the control part (51); the resistor AR60 is connected with the capacitor AC53 in parallel; One end of the switch part (52) is grounded; the other end of the switch part (52) is connected with the control end of the charge-discharge switch tube MD1 through the first switch module; the switch end of the charge-discharge switch tube MD1 is connected with the positive output (41) and the negative output (42) respectively.

2. The battery pack open-circuit detection circuit of claim 1, wherein: The first switch module includes triode AQ12, triode AQ13 and triode AQ9; The other end of the switch part (52) is connected with the base of triode AQ12; the emitter of triode AQ12 is connected with the power supply; the collector of triode AQ12 is connected with the base of triode AQ13; the emitter of triode AQ13 is grounded; the emitter of triode AQ13 is connected with the base of triode AQ9; the collector of triode AQ9 is grounded; the emitter of triode AQ9 is connected with the control end of the charge-discharge switch tube MD1.

3. The battery pack open-circuit detection circuit of claim 2, wherein: The first switch module further includes triode AQ6 and triode AQ8; the collector of triode AQ6 and the collector of triode AQ8 are connected with the power supply respectively; the emitter of triode AQ6 is connected with the collector of triode AQ8; the emitter of triode AQ8 is connected with the control end of the charge-discharge switch tube MD1; the base of triode AQ8 is connected with the base of triode AQ9.

4. The battery pack open-circuit detection circuit of claim 3, wherein: The first switch module further includes a control port (6), diode AD12, diode AD13 and resistor AR80; the control port (6) is connected with the negative pole of diode AD12 through resistor AR80; the positive pole of diode AD12 is connected with the base of triode AQ6; the positive pole of diode AD12 is connected with the negative pole of diode AD13; the positive pole of diode AD13 is connected with the base of triode AQ8.

5. The battery pack open-circuit detection circuit of claim 4, wherein: The battery pack open circuit detection circuit also includes an MCU controller; the other end of the switch (52) and the control port (6) are respectively connected to the MCU controller.

6. The battery pack open-circuit detection circuit of claim 1, wherein: The triggering element is an optocoupler AU3.

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