Intelligent grounding switching charging and discharging circuit and aging cabinet

Abstract

The invention relates to the technical field of battery testing, and discloses an intelligent grounding switching charging and discharging circuit and an aging cabinet. The voltage identification module is used for identifying the charging and discharging state of the battery to be tested and outputting a control signal; the switching module comprises at least two grounding branches with different resistance values, and the control unit selectively enables any grounding branch resistor to be electrically connected with the identification port according to a control signal, so that the battery management system identifies the charging and discharging states; when a battery to be tested is normally connected to the intelligent grounding switching charging and discharging circuit, the anode of the battery is electrically connected with the anode main line, the cathode of the battery is electrically connected with the cathode main line, and the control device identifies whether the anode main line is correctly and electrically connected with the anode of the battery to be tested. The on-off of the switch unit is controlled according to the identification result; on the premise of not needing complex circuit and program control, intelligent adjustment of the charging and discharging states of the battery to be tested is achieved, and potential safety hazards caused by the fact that the charging and discharging states cannot be recognized or are mistakenly recognized are effectively eradicated.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to an intelligent grounding switching charging and discharging circuit and an aging cabinet. Background Art

[0002] In the field of new energy battery testing, the aging cabinet is a core device and its function is crucial. It not only needs to realize the automatic switching of charging and discharging, but also must meet diverse requirements such as multi-protocol compatibility, wide voltage range adaptation, and complex grounding logic control. With the widespread application of new chemical systems such as lithium batteries and solid-state batteries, the intelligence level of battery management systems (BMS) continues to improve, and more refined requirements are also put forward for charging identification logic. Some products need to identify different resistance grounding before they can perform charging and discharging operations. The charging and discharging logic of a certain product is as follows:

[0003] (1) Charging stage: It needs to be connected to ground through a 4.7kΩ±5% precision resistor (as required by the Infineon CPT003 protocol) to trigger the charging handshake signal.

[0004] (2) Discharge stage: 0Ω is required to be directly grounded to eliminate voltage division loss and ensure that the discharge BMS can correctly identify the discharge signal.

[0005] In the application of battery management systems (BMS) and burn-in cabinets, traditional technology primarily relies on manually operated mechanical switches to adjust the grounding resistor to suit the battery's charge and discharge status. Furthermore, some burn-in cabinets employ fixed resistor designs to simplify the equipment structure. Other companies are experimenting with controlling the charge and discharge processes of the burn-in cabinets through specialized test procedures, achieving a degree of automation. At the same time, some companies are upgrading their burn-in cabinets to incorporate new equipment that supports multiple resistance value switching to meet diverse testing needs.

[0006] In existing technology, when a battery management system (BMS) is paired with equipment from different manufacturers, it is usually necessary to switch between grounding resistors of different values ​​according to the charge and discharge phases. However, traditional burn-in cabinets have some limitations in this application scenario.

[0007] 1. Rigid switching mechanism: Relying on mechanical switches or fixed resistors, it cannot automatically switch resistance values ​​according to charge and discharge status, resulting in poor device compatibility.

[0008] 2. Lack of dynamic control: Traditional on-off control methods require manual switching and are unsuitable for mass production scenarios. In some cases, specialized test procedures are used for aging testing, but this method carries risks because the test procedures are inconsistent with the actual factory procedures, which can lead to unexpected situations and even dangerous overcharge protection failures. Furthermore, excessive reliance on manual or simple circuit designs and a lack of intelligent adjustment mechanisms can result in the battery management system (BMS) being unable to effectively adapt to changes in battery status, affecting charging and discharging performance and even posing safety risks.

[0009] 3. Safety hazards: The aging cabinet has a long working time, and the equipment may lack maintenance. It may still carry a small voltage (<20V) when not charging, which can easily cause false triggering or battery damage. When the battery is abnormal, it may discharge reversely into the aging cabinet, and there is no quick disconnection mechanism.

[0010] 4. Cost and compatibility conflict: In addition, purchasing a new burn-in cabinet to support multi-resistance switching is expensive and difficult to cover diverse testing scenarios.

[0011] Therefore, there is an urgent need for intelligent grounding switching charging and discharging circuits and aging cabinets to overcome the above defects. Summary of the Invention

[0012] The object of the present invention is to provide an intelligent grounding switching charging and discharging circuit and an aging cabinet to solve or at least partially solve the technical problems existing in the prior art.

[0013] To achieve this object, the present invention adopts the following technical solutions:

[0014] In a first aspect, the present invention provides an intelligent grounding switching charging and discharging circuit, which includes a positive main line, a negative main line, an identification port, a voltage identification module, a switching module, an anti-reverse connection module and a power supply module, wherein the negative main line is grounded, the power supply module supplies power to the voltage identification module and the switching module respectively, and the identification port is used to electrically connect to the battery management system of the battery to be tested;

[0015] The voltage identification module is used to collect the input voltage of the positive main line and compare it with a reference voltage to identify the charge and discharge status of the battery to be tested, and output a control signal according to the charge and discharge status;

[0016] The switching module includes a control unit and at least two grounding branches with different resistance values. The control unit selectively connects the resistor of any one of the grounding branches to the identification port according to the control signal, so that the battery management system can identify the charge and discharge status of the battery to be tested based on the currently connected grounding branch.

[0017] The anti-reverse connection module includes a control device and a switch unit. The switch unit is connected in series to the positive main line. When the battery to be tested is normally connected to the intelligent grounding switching charge and discharge circuit, the positive electrode of the battery is electrically connected to the positive main line, and the negative electrode is electrically connected to the negative main line. The control device identifies whether the positive main line is correctly electrically connected to the positive electrode of the battery to be tested, and controls the on and off of the switch unit according to the identification result.

[0018] Preferably, the voltage identification module includes a voltage divider unit, a reference unit and a voltage comparison unit. The voltage divider unit and the reference unit are connected in parallel and connected between the positive main line and the negative main line. The non-inverting input end of the voltage comparison unit is electrically connected to the reference unit, the inverting input end is electrically connected to the voltage divider unit, the output end is electrically connected to the switching module, the positive power supply end is connected to the power supply module, and the negative power supply end is electrically connected to the negative main line. The voltage divider unit outputs a divided voltage to the voltage comparison unit based on the voltage relationship between the positive main line and the negative main line. The reference unit outputs a reference voltage to the voltage comparison unit based on the voltage relationship between the positive main line and the negative main line. The voltage comparison unit outputs the control signal to the switching module based on the divided voltage and the reference voltage.

[0019] Specifically, the voltage divider unit includes a first resistor, a third resistor and a fifth resistor, the reference unit includes a second resistor, the first resistor, the third resistor and the fifth resistor are connected in series in sequence, the end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive main line, the end of the fifth resistor away from the third resistor is electrically connected to the negative main line, the second end of the second resistor is electrically connected to the negative main line, the non-inverting input end of the voltage comparison unit is electrically connected between the second end of the second resistor and the negative main line, and the inverting input end is electrically connected between the third resistor and the fifth resistor.

[0020] More specifically, the voltage identification module further includes a fifth anti-reverse diode, the reference unit further includes a first zener diode, the second end of the second resistor is electrically connected to the negative main line through the first zener diode, and the anode of the first zener diode is electrically connected to the second end of the second resistor, and the cathode is grounded, and the non-inverting input terminal of the voltage comparison unit is electrically connected between the second end of the second resistor and the anode of the first zener diode;

[0021] One end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive main line through the fifth anti-reverse diode, and one end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive electrode of the fifth anti-reverse diode.

[0022] Preferably, the switching module includes a first grounding branch and a second grounding branch, the control unit includes a relay, a third transistor, a first gate resistor, a second gate resistor, a sixth resistor and an eleventh resistor, the first grounding branch includes a fourth resistor, the second grounding branch includes a first anti-reverse diode, the common end of the relay is electrically connected to the identification port, the normally closed end is electrically connected to the negative electrode of the first anti-reverse diode, the normally open end is electrically connected to the negative main line through the fourth resistor, the positive power supply end is electrically connected to the collector of the third transistor, and the negative power supply end is grounded, the first gate resistor, the second gate resistor and the eleventh resistor are connected in series in sequence, and the end of the first gate resistor away from the second gate resistor is electrically connected to the power supply in parallel with the first end of the sixth resistor, the end of the eleventh resistor away from the second gate resistor is connected to the output end of the voltage comparison unit, the second end of the sixth resistor is electrically connected to the emitter of the third transistor, and the base of the third transistor is connected between the first gate resistor and the second gate resistor.

[0023] Specifically, the switching module further includes a third anti-reverse diode and an acceleration circuit, wherein the anode of the third anti-reverse diode is connected between the positive power supply terminal of the relay and the collector of the third transistor, the cathode is grounded, and the cathode power supply terminal of the relay is connected between the cathode of the third anti-reverse diode and the ground;

[0024] The acceleration circuit is used to accelerate the closing of the relay. The acceleration circuit is arranged in parallel with the sixth resistor. The acceleration circuit includes an acceleration capacitor and a fourteenth resistor arranged in parallel.

[0025] Preferably, the control device includes a first transistor, a second transistor, a ninth resistor and a tenth resistor, the switching unit includes a field effect transistor, the field effect transistor is connected in series to the positive main line, the emitter of the first transistor is electrically connected to the drain of the field effect transistor, the collector is grounded through the ninth resistor, the base is connected in parallel with the base of the second transistor and then connected between the collector of the first transistor and the ninth resistor, the emitter of the second transistor is electrically connected to the source of the field effect transistor, the collector is grounded through the tenth resistor, and the gate of the field effect transistor is connected between the collector of the second transistor and the tenth resistor.

[0026] Specifically, the control device further includes a second anti-reverse diode, a fourth anti-reverse diode, a second voltage-stabilizing diode, an eighth resistor, and a thirteenth resistor. The emitter of the second transistor is electrically connected to the source of the field-effect transistor through the second anti-reverse diode, and the emitter of the second transistor is connected to the anode of the second anti-reverse diode. The emitter of the first transistor is electrically connected to the drain of the field-effect transistor through the fourth anti-reverse diode, and the emitter of the first transistor is connected to the anode of the fourth anti-reverse diode. The gate of the field-effect transistor is connected between the collector of the second transistor and the tenth resistor through the eighth resistor. The anode of the second voltage-stabilizing diode is electrically connected to the positive main line and is located between the anode of the second anti-reverse diode and the source of the field-effect transistor, and the cathode is electrically connected between the gate of the field-effect transistor and the eighth resistor. One end of the thirteenth resistor is electrically connected to the positive main line and is located between the source of the field-effect transistor and the anode of the second voltage-stabilizing diode. The other end is connected in parallel with the cathode of the second voltage-stabilizing diode and then connected between the gate of the field-effect transistor and the eighth resistor.

[0027] Preferably, the first transistor, the second transistor and the third transistor are triodes of the same type, the field effect tube is a PMOS field effect tube, the voltage comparison unit is a voltage comparator, and the power supply module can adapt to a wide input voltage of 6V to 100V.

[0028] In a second aspect, the present invention further provides a burn-in cabinet, which includes the intelligent grounding switching charging and discharging circuit as described above.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The voltage identification module identifies the charge and discharge status of the battery under test, and controls the switching module to switch to the grounding branch corresponding to the current charge and discharge status, so that the battery management system of the battery under test can identify the charge and discharge status of the battery under test according to the currently connected grounding branch. Without the need for complex circuits and program control, it realizes intelligent adjustment of the charge and discharge status of the battery under test, effectively avoiding the battery management system of the battery under test from being unable to effectively adapt to the changes in the charge and discharge status of the battery under test, which affects the charge and discharge effect, and effectively eliminates the safety hazards caused by the inability to identify or misidentify the charge and discharge status;

[0031] 2. By setting up an anti-reverse connection module, the control device identifies whether the positive main line is correctly electrically connected to the positive electrode of the battery to be tested. If it is correctly connected, the control switch unit is turned on, and the device charges or discharges the battery to be tested. If it is incorrectly connected (such as the positive and negative poles of the battery to be tested are reversely connected to the positive main line and the negative main line), the control switch unit is disconnected, and the device does not charge or discharge the battery to be tested, thereby ensuring that the battery to be tested will not reversely discharge to the device under abnormal circumstances, effectively avoiding safety hazards caused by reverse discharge of the battery to be tested.

[0032] The present invention has other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain certain principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 4 is a circuit diagram of an intelligent grounding switching charging and discharging circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0036] See also Figure 1 The burn-in cabinet of the present invention includes an intelligent grounding switching charge-discharge circuit suitable for performing charge-discharge aging tests on a battery under test (not shown). Of course, the intelligent grounding switching charge-discharge circuit can also be applied to other devices involving battery charging and discharging. The batteries under test here are primarily rechargeable and dischargeable batteries such as lithium batteries or solid-state batteries. The circuit structure of the intelligent grounding switching charge-discharge circuit of the present invention will be described in detail below.

[0037] See also Figure 1The intelligent grounding switching charging and discharging circuit of the present invention includes a positive main line 10, a negative main line 20, an identification port 30, a voltage identification module 40, a switching module 50, an anti-reverse connection module 60 and a power supply module 70, wherein the negative main line 20 is grounded, the power supply module 70 supplies power to the voltage identification module 40 and the switching module 50 respectively, and the identification port 30 is used to electrically connect to the battery management system of the battery to be tested.

[0038] It is understood that when the battery under test needs to be charged or discharged, the battery under test is placed in the aging cabinet, with the positive electrode of the battery under test electrically connected to the positive main line 10, the negative electrode electrically connected to the negative main line 20, and its battery management system electrically connected to the identification port 30. By adjusting the voltage difference between the positive main line 10 and the negative main line 20, the charging and discharging actions of the aging cabinet on the battery under test can be switched in real time without adjusting the position of the battery under test or other parameters of the aging cabinet.

[0039] Preferably, the power supply module 70 can accommodate a wide input voltage range of 6V to 100V, adapting to low-voltage and industrial-grade high-voltage applications, greatly meeting the needs of a wider range of application scenarios. Specifically, the power supply module 70 can use a power supply model LM5163DDAR to meet the wide input voltage requirements of 6V to 100V and stably provide 12V power to the voltage identification module 40 and the switching module 50.

[0040] The voltage identification module 40 is used to collect the input voltage of the positive main line 10 and compare it with a reference voltage to identify the charge and discharge status of the battery under test and output a control signal based on the charge and discharge status. Because the negative main line 20 is grounded, the collected input voltage of the positive main line 10 is the voltage between the positive and negative main lines 10 and 20.

[0041] The switching module 50 includes a control unit 51 and at least two grounding branches with different resistance values. The switching module 50 receives a control signal fed back from the voltage identification module 40. The control unit 51 selectively connects the resistance of any grounding branch to the identification port 30 according to the control signal, so that the battery management system can identify the charge and discharge status of the battery to be tested based on the currently connected grounding branch.

[0042] For example, if the battery to be tested in the embodiment is placed in an aging cabinet for charging and discharging, only two grounding branches with different resistance values ​​are needed to meet the requirements, corresponding to the current resistance standard for the battery management system on the market to identify battery charging and discharging. A grounding branch with a resistance of 4.7kΩ can be used by the battery management system to identify that the battery is in a charging state, and a grounding branch with a resistance of 0Ω can be used by the battery management system to identify that the battery is in a discharging state.

[0043] Of course, if it is necessary to identify more states of the battery under test in the aging cabinet, such as standby state, overcharge state, over-discharge state, thermal protection state, balance state, self-discharge state, etc., a grounding branch with a corresponding resistance value can be added to meet the identification needs of more states. I will not go into details here.

[0044] The anti-reverse connection module 60 includes a control device and a switch unit. The switch unit is connected in series to the positive main line 10. When the battery to be tested is normally connected to the intelligent grounding switching charge and discharge circuit, the positive pole of the battery is electrically connected to the positive main line 10, and the negative pole is electrically connected to the negative main line 20. The control device identifies whether the positive main line 10 is correctly electrically connected to the positive pole of the battery to be tested, and controls the on and off of the switch unit according to the identification result.

[0045] For the situation where the battery to be tested is not normally connected to the intelligent grounding switching charging and discharging circuit, it is mainly because the battery to be tested is reversely connected to the intelligent grounding switching charging and discharging circuit, that is, the positive pole of the battery is electrically connected to the negative pole main line 20, and the negative pole is electrically connected to the positive pole main line 10. When the battery to be tested is reversely connected, the intelligent grounding switching charging and discharging circuit will cause the battery to be tested to be unable to charge and discharge, and the circuit will also be damaged due to the reverse connection of the battery to be tested. The anti-reverse connection module 60 can effectively avoid circuit damage caused by reverse connection.

[0046] Of course, if the battery to be tested is not properly connected to the intelligent grounding switching charging and discharging circuit due to reasons such as not being placed in place or having poor contact, the voltage identification module 40 will detect that the voltage is unstable or smaller than expected, and will not be able to output an effective control signal, and the aging cabinet will not charge or discharge the battery to be tested.

[0047] Preferably, the voltage identification module 40 includes a voltage divider unit 41, a reference unit 42, and a voltage comparison unit 43. The voltage divider unit 41 and the reference unit 42 are connected in parallel and connected between the positive main line 10 and the negative main line 20. Preferably, the voltage comparison unit 43 here is a voltage comparator, such as a voltage comparator of model LM393BIDR. The non-inverting input terminal of the voltage comparison unit 43 is electrically connected to the reference unit 42, the inverting input terminal is electrically connected to the voltage divider unit 41, the output terminal is electrically connected to the switching module 50, the positive power supply terminal is connected to the power supply module 70, and the negative power supply terminal is electrically connected to the negative main line 20. The voltage divider unit 41 outputs a divided voltage to the voltage comparison unit 43 based on the voltage relationship between the positive main line 10 and the negative main line 20. The reference unit 42 outputs a reference voltage to the voltage comparison unit 43 based on the voltage relationship between the positive main line 10 and the negative main line 20. The voltage comparison unit 43 outputs a control signal to the switching module 50 based on the divided voltage and the reference voltage.

[0048] Specifically, the voltage divider unit 41 includes a first resistor R1, a third resistor R3 and a fifth resistor R5, and the reference unit 42 includes a second resistor R2. The first resistor R1, the third resistor R3 and the fifth resistor R5 are connected in series in sequence. The end of the first resistor R1 away from the third resistor R3 is connected in parallel with the first end of the second resistor R2 and is electrically connected to the positive main line 10. The end of the fifth resistor R5 away from the third resistor R3 is electrically connected to the negative main line 20. The second end of the second resistor R2 is electrically connected to the negative main line 20. The non-inverting input end of the voltage comparison unit 43 is electrically connected between the second end of the second resistor R2 and the negative main line 20, and the inverting input end is electrically connected between the third resistor R3 and the fifth resistor R5.

[0049] More specifically, the voltage identification module 40 further includes a fifth anti-reverse diode D5, the reference unit 42 further includes a first Zener diode DZ1, the second end of the second resistor R2 is electrically connected to the negative main line 20 through the first Zener diode DZ1, and the anode of the first Zener diode DZ1 is electrically connected to the second end of the second resistor R2, and the cathode is grounded. The non-inverting input terminal of the voltage comparison unit 43 is electrically connected between the second end of the second resistor R2 and the anode of the first Zener diode DZ1;

[0050] One end of the first resistor R1 away from the third resistor R3 is connected in parallel with the first end of the second resistor R2 and then electrically connected to the positive main line 10 through the fifth anti-reverse diode D5. The other end of the first resistor R1 away from the third resistor R3 is connected in parallel with the first end of the second resistor R2 and then electrically connected to the anode of the fifth anti-reverse diode D5.

[0051] Taking the reference voltage of 20V as an example, the parameters of each component are matched. At this time, the first voltage regulator diode DZ1 model is BZT55C5V1-CM, the first resistor R1 resistance is 51KΩ, the second resistor R2 resistance is 100Ω, the second resistor R3 resistance is 51KΩ, the fifth resistor R5 resistance is 36KΩ, and the fifth anti-reverse diode D5 model is IN4148WS.

[0052] The first resistor R1 , the third resistor R3 and the fifth resistor R5 together form a voltage divider network, and the second resistor R2 and the first voltage stabilizing diode DZ1 work together to obtain a voltage reference of 5.1V.

[0053] Preferably, the switching module 50 includes a first grounding branch 521 and a second grounding branch 522, the control unit 51 includes a relay KA, a third transistor Q3, a first gate resistor RG1, a second gate resistor RG2, a sixth resistor R6 and an eleventh resistor R11, the first grounding branch 521 includes a fourth resistor R4, the second grounding branch 522 includes a first anti-reverse diode D1, the common end of the relay KA is electrically connected to the identification port 30, the normally closed end is electrically connected to the cathode of the first anti-reverse diode D1, the normally open end is electrically connected to the negative main line 20 through the fourth resistor R4, and the positive power supply end is electrically connected to the negative main line 20. The collector of the third transistor Q3 is connected, the negative power supply terminal is grounded, the first gate resistor RG1, the second gate resistor RG2, and the eleventh resistor R11 are connected in series in sequence, and the end of the first gate resistor RG1 away from the second gate resistor RG2 is connected in parallel with the first end of the sixth resistor R6 and then electrically connected to the power supply. The end of the eleventh resistor R11 away from the second gate resistor RG2 is connected to the output terminal of the voltage comparison unit 43. The second end of the sixth resistor R6 is electrically connected to the emitter of the third transistor Q3. The base of the third transistor Q3 is connected between the first gate resistor RG1 and the second gate resistor RG2.

[0054] Specifically, the switching module 50 further includes a third anti-reverse diode D3 and an acceleration circuit 53. The anode of the third anti-reverse diode D3 is connected between the positive power supply terminal of the relay KA and the collector of the third transistor Q3, and the cathode is grounded. The negative power supply terminal of the relay KA is connected between the cathode of the third anti-reverse diode D3 and the ground.

[0055] The acceleration circuit 53 is used to accelerate the closing of the relay KA. The acceleration circuit 53 is connected in parallel with the sixth resistor R6. The acceleration circuit 53 includes an acceleration capacitor EC and a fourteenth resistor R14 connected in parallel.

[0056] It's understandable that relay KA initially requires a higher current to conduct, but the current decreases after stabilization. However, when acceleration capacitor EC is powered on, the circuit is instantly nearly conductive, and relay KA closes. Therefore, adding acceleration circuit 53 reduces the power consumption of the circuit, allowing relay KA to conduct normally even with a larger resistor.

[0057] The switching module 50 switches between the 4.7KΩ and 0Ω grounding states via relay KA. When the burn-in cabinet input voltage (i.e., the voltage between the positive main line 10 and the negative main line 20) is greater than 20V, the third transistor Q3 turns on, energizing the coil of relay KA, short-circuiting the common terminal and the normally open terminal, and the battery under test recognizes the 4.7KΩ resistor grounding signal.

[0058] Specifically, when the input voltage of the positive main line 10 acquired by the voltage identification module 40 is 20V, the fifth resistor R5 is 5V, and when the non-inverting input terminal and the inverting input terminal of the voltage comparison unit 43 are both within the common mode range:

[0059] a. If the voltage of the inverting input terminal is higher than the voltage of the non-inverting input terminal and the offset voltage, the output terminal of the voltage comparison unit 43 outputs a low level, and the third transistor Q3 of the switching module 50 will inject current;

[0060] b. If the voltage at the inverting input terminal is lower than the voltage at the non-inverting input terminal and the offset voltage, the output terminal of the voltage comparison unit 43 outputs a high impedance, and the third transistor Q3 of the switching module 50 is not turned on.

[0061] It is worth noting that the offset voltage here refers to the voltage difference between the input terminals where the output voltage just jumps (from low to high or from high to low) when the voltages at the non-inverting input terminal and the inverting input terminal of the voltage comparison unit 43 are completely equal. The typical offset voltage of the voltage comparator model LM393BIDR is ±0.37mV.

[0062] The following table shows the relationship among the input voltage, the voltage comparison unit 43, the relay KA, the grounding resistance, and the battery identification mode:

[0063]

[0064] Preferably, the control device includes a first transistor Q1, a second transistor Q2, a ninth resistor R9, and a tenth resistor R10. The switch unit includes a field-effect transistor MC, which is connected in series with the positive main line 10. The emitter of the first transistor Q1 is electrically connected to the drain of the field-effect transistor MC, the collector is grounded via the ninth resistor R9, the base is connected in parallel with the base of the second transistor Q2, and is connected between the collector of the first transistor Q1 and the ninth resistor R9. The emitter of the second transistor Q2 is electrically connected to the source of the field-effect transistor MC, the collector is grounded via the tenth resistor R10, and the gate of the field-effect transistor MC is connected between the collector of the second transistor Q2 and the tenth resistor R10. Preferably, the field-effect transistor MC is a PMOS field-effect transistor, and the first transistor Q1, the second transistor Q2, and the third transistor Q3 are transistors of the same type, all of which are PNP transistors.

[0065] Specifically, the control device further includes a second anti-reverse diode D2, a fourth anti-reverse diode D4, a second voltage stabilizing diode DZ2, an eighth resistor R8, and a thirteenth resistor R13. The emitter of the second transistor Q2 is electrically connected to the source of the field effect transistor MC through the second anti-reverse diode D2, and the emitter of the second transistor Q2 is connected to the anode of the second anti-reverse diode D2. The emitter of the first transistor Q1 is electrically connected to the drain of the field effect transistor MC through the fourth anti-reverse diode D4, and the emitter of the first transistor Q1 is connected to the anode of the fourth anti-reverse diode D4. The gate of the field effect transistor MC is connected to the anode of the fourth anti-reverse diode D4. Resistor R8 is connected between the collector of the second transistor Q2 and the tenth resistor R10. The anode of the second voltage-stabilizing diode DZ2 is electrically connected to the positive main line 10 and is located between the anode of the second anti-reverse diode D2 and the source of the field-effect transistor MC. The cathode is electrically connected between the gate of the field-effect transistor MC and the eighth resistor R8. One end of the thirteenth resistor R13 is electrically connected to the positive main line 10 and is located between the source of the field-effect transistor MC and the anode of the second voltage-stabilizing diode DZ2. The other end is connected in parallel with the cathode of the second voltage-stabilizing diode DZ2 and then connected between the gate of the field-effect transistor MC and the eighth resistor R8.

[0066] It can be understood that in this embodiment, the first transistor Q1, the second transistor Q2, the field-effect transistor MC and peripheral electronic components are used to construct an ideal diode to replace the traditional diode, thereby reducing the forward voltage drop to below 0.1V, greatly reducing the loss of charging current passing through the ideal diode, and significantly improving the energy conversion efficiency.

[0067] During reverse polarity protection, when the power supply voltage is normal (i.e., the battery under test is properly connected to the intelligent grounding switching charge and discharge circuit), the base voltage (Vb) of the second transistor Q2 is determined by subtracting the base-emitter voltage (Vbe) from the power supply voltage (i.e., the voltage at its emitter). For example, if the battery under test voltage is 5V, the power supply voltage is 5V, and Vbe is -0.7V, then Vb = 5V - 0.7V = 4.3V.

[0068] Since the first transistor Q1 and the second transistor Q2 are transistors of the same model and their bases are connected, the base voltage of the second transistor Q2 is also equal to 4.3 V. At this time, the emitter currents of the first transistor Q1 and the second transistor Q2 form a mirror current through the ninth resistor R9 and the tenth resistor R10, so that the current flowing through the first transistor Q1 is almost equal to the current flowing through the second transistor Q2.

[0069] The calculation process of the mirror current formed by the emitter current of the first transistor Q1 and the second transistor Q2 through the ninth resistor R9 and the tenth resistor R10 is as follows:

[0070] Since the first transistor Q1 and the second transistor Q2 are the same type of transistor, the base current Ib1 ≈ Ib2. The currents flowing through the collectors of the first transistor Q1 and the second transistor Q2 are Ic1 and Ic2, respectively. The current flowing through the ninth resistor R9, Ir1 = Ic1 + Ib1 + Ib2 = βIb1 + Ib1 + Ib2. Assuming β = 100, then Ir1 = 102Ib1 = 102Ib2. Since βIb2 = Ic2, the current flowing through the tenth resistor R10 is almost equal to the current Ir1 flowing through the ninth resistor R9. This means that the current flowing through the first transistor Q1 is mirrored to the second transistor Q2, forming a mirrored current source.

[0071] At this point, the gate-source voltage (Vgs) of FET MC is clamped to -18V by the voltage regulator, turning on FET MC and allowing current to flow from the power source through FET MC to the load. At this point, FET MC's body diode (a diode naturally formed between the source and drain of FET MC due to its structural characteristics, known as the body diode) is short-circuited, and current flows primarily through FET MC's channel, similar to the forward conduction state of an ideal diode.

[0072] When the power supply voltage is reversed (i.e., the positive and negative poles of the battery under test are reversed in the intelligent ground switching charge and discharge circuit), the gate-source voltage (Vgs) of the FET MC becomes positive, and the FET MC cannot conduct. At this time, the body diode of the FET MC also does not conduct, thus preventing the reverse flow of current and eliminating damage to the device caused by reverse connection of the battery under test.

[0073] Combine Figure 1 , the present invention has the following beneficial effects:

[0074] 1. The voltage identification module 40 identifies the charge and discharge status of the battery under test, thereby controlling the switching module 50 to switch to the grounding branch corresponding to the current charge and discharge status. This allows the battery management system of the battery under test to identify the charge and discharge status of the battery under test based on the currently connected grounding branch. This achieves intelligent adjustment of the charge and discharge status of the battery under test without the need for complex circuits and program control, effectively avoiding the impact on the charge and discharge effect caused by the battery management system of the battery under test being unable to effectively adapt to changes in the charge and discharge battery status, and effectively eliminating safety hazards caused by the inability to identify or misidentify the charge and discharge status.

[0075] 2. By setting up an anti-reverse connection module 60, the control device identifies whether the positive main line 10 is correctly electrically connected to the positive electrode of the battery to be tested. If it is correctly connected, the switch unit is controlled to be turned on, and the device charges or discharges the battery to be tested. If it is incorrectly connected (such as the positive and negative poles of the battery to be tested are reversely connected to the positive main line 10 and the negative main line 20), the switch unit is controlled to be disconnected, and the device does not charge or discharge the battery to be tested, thereby ensuring that the battery to be tested will not discharge reversely to the device under abnormal circumstances, effectively avoiding safety hazards caused by reverse discharge of the battery to be tested.

[0076] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent ground switching charging and discharging circuit, characterized in that: It includes a positive main line, a negative main line, an identification port, a voltage identification module, a switching module, an anti-reverse connection module and a power supply module. The negative main line is grounded. The power supply module supplies power to the voltage identification module and the switching module respectively. The identification port is used to electrically connect to the battery management system of the battery to be tested; The voltage identification module is used to collect the input voltage of the positive main line and compare it with a reference voltage to identify the charge and discharge status of the battery to be tested, and output a control signal according to the charge and discharge status; The switching module includes a control unit and at least two grounding branches with different resistance values. The control unit selectively connects the resistor of any one of the grounding branches to the identification port according to the control signal, so that the battery management system can identify the charge and discharge status of the battery to be tested based on the currently connected grounding branch. The anti-reverse connection module includes a control device and a switch unit. The switch unit is connected in series to the positive main line. When the battery to be tested is normally connected to the intelligent grounding switching charge and discharge circuit, the positive electrode of the battery is electrically connected to the positive main line, and the negative electrode is electrically connected to the negative main line. The control device identifies whether the positive main line is correctly electrically connected to the positive electrode of the battery to be tested, and controls the on and off of the switch unit according to the identification result.

2. The intelligent grounding switching charging and discharging circuit according to claim 1, wherein: The voltage identification module includes a voltage divider unit, a reference unit and a voltage comparison unit. The voltage divider unit and the reference unit are connected in parallel and connected between the positive main line and the negative main line. The non-inverting input end of the voltage comparison unit is electrically connected to the reference unit, the inverting input end is electrically connected to the voltage divider unit, the output end is electrically connected to the switching module, the positive power supply end is connected to the power supply module, and the negative power supply end is electrically connected to the negative main line. The voltage divider unit outputs a divided voltage to the voltage comparison unit based on the voltage relationship between the positive main line and the negative main line. The reference unit outputs a reference voltage to the voltage comparison unit based on the voltage relationship between the positive main line and the negative main line. The voltage comparison unit outputs the control signal to the switching module based on the divided voltage and the reference voltage.

3. The intelligent grounding switching charging and discharging circuit according to claim 2, wherein: The voltage divider unit includes a first resistor, a third resistor and a fifth resistor, and the reference unit includes a second resistor. The first resistor, the third resistor and the fifth resistor are connected in series in sequence. An end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive main line. An end of the fifth resistor away from the third resistor is electrically connected to the negative main line, and the second end of the second resistor is electrically connected to the negative main line. The non-inverting input end of the voltage comparison unit is electrically connected between the second end of the second resistor and the negative main line, and the inverting input end is electrically connected between the third resistor and the fifth resistor.

4. The intelligent grounding switching charging and discharging circuit according to claim 3, wherein: The voltage identification module further includes a fifth anti-reverse diode, the reference unit further includes a first zener diode, the second end of the second resistor is electrically connected to the negative main line through the first zener diode, and the anode of the first zener diode is electrically connected to the second end of the second resistor, and the cathode is grounded, and the non-inverting input terminal of the voltage comparison unit is electrically connected between the second end of the second resistor and the anode of the first zener diode; One end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive main line through the fifth anti-reverse diode, and one end of the first resistor away from the third resistor is connected in parallel with the first end of the second resistor and then electrically connected to the positive electrode of the fifth anti-reverse diode.

5. The intelligent grounding switching charging and discharging circuit according to claim 2, wherein: The switching module includes a first grounding branch and a second grounding branch, the control unit includes a relay, a third transistor, a first gate resistor, a second gate resistor, a sixth resistor and an eleventh resistor, the first grounding branch includes a fourth resistor, the second grounding branch includes a first anti-reverse diode, the common end of the relay is electrically connected to the identification port, the normally closed end is electrically connected to the negative electrode of the first anti-reverse diode, the normally open end is electrically connected to the negative main line through the fourth resistor, the positive power supply end is electrically connected to the collector of the third transistor, and the negative power supply end is grounded, the first gate resistor, the second gate resistor and the eleventh resistor are connected in series in sequence, and the end of the first gate resistor away from the second gate resistor is connected in parallel with the first end of the sixth resistor and then electrically connected to the power supply, the end of the eleventh resistor away from the second gate resistor is connected to the output end of the voltage comparison unit, the second end of the sixth resistor is electrically connected to the emitter of the third transistor, and the base of the third transistor is connected between the first gate resistor and the second gate resistor.

6. The intelligent grounding switching charging and discharging circuit according to claim 5, characterized in that: The switching module further includes a third anti-reverse diode and an acceleration circuit, wherein the anode of the third anti-reverse diode is connected between the positive power supply terminal of the relay and the collector of the third transistor, the cathode is grounded, and the cathode power supply terminal of the relay is connected between the cathode of the third anti-reverse diode and the ground; The acceleration circuit is used to accelerate the closing of the relay. The acceleration circuit is arranged in parallel with the sixth resistor. The acceleration circuit includes an acceleration capacitor and a fourteenth resistor arranged in parallel.

7. The intelligent grounding switching charging and discharging circuit according to claim 5, characterized in that: The control device includes a first transistor, a second transistor, a ninth resistor and a tenth resistor. The switching unit includes a field effect transistor, which is connected in series to the positive main line. The emitter of the first transistor is electrically connected to the drain of the field effect transistor, the collector is grounded through the ninth resistor, the base is connected in parallel with the base of the second transistor and then connected between the collector of the first transistor and the ninth resistor, the emitter of the second transistor is electrically connected to the source of the field effect transistor, the collector is grounded through the tenth resistor, and the gate of the field effect transistor is connected between the collector of the second transistor and the tenth resistor.

8. The intelligent grounding switching charging and discharging circuit according to claim 7, characterized in that: The control device also includes a second anti-reverse diode, a fourth anti-reverse diode, a second voltage-stabilizing diode, an eighth resistor, and a thirteenth resistor. The emitter of the second transistor is electrically connected to the source of the field-effect transistor via the second anti-reverse diode, and the emitter of the second transistor is connected to the anode of the second anti-reverse diode. The emitter of the first transistor is electrically connected to the drain of the field-effect transistor via the fourth anti-reverse diode, and the emitter of the first transistor is connected to the anode of the fourth anti-reverse diode. The gate of the field-effect transistor is connected between the collector of the second transistor and the tenth resistor via the eighth resistor. The anode of the second voltage-stabilizing diode is electrically connected to the positive main line and is located between the anode of the second anti-reverse diode and the source of the field-effect transistor, and the cathode is electrically connected between the gate of the field-effect transistor and the eighth resistor. One end of the thirteenth resistor is electrically connected to the positive main line and is located between the source of the field-effect transistor and the anode of the second voltage-stabilizing diode. The other end is connected in parallel with the cathode of the second voltage-stabilizing diode and is connected between the gate of the field-effect transistor and the eighth resistor.

9. The intelligent grounding switching charging and discharging circuit according to claim 8, characterized in that: The first transistor, the second transistor and the third transistor are triodes of the same type, the field effect tube is a PMOS field effect tube, the voltage comparison unit is a voltage comparator, and the power supply module can adapt to a wide input voltage of 6V to 100V.

10. An aging cabinet, characterized by: The intelligent ground switching charging and discharging circuit comprises the intelligent ground switching charging and discharging circuit according to any one of claims 1 to 9.

Images