Battery parallel low-temperature protection circuit suitable for cathode charging protection system

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By designing a battery parallel low-temperature protection circuit suitable for negative electrode charging protection system, the microprocessor chip and a specific MOS tube and photocoupler combination control the heating film when the battery is connected in parallel, solving the problem of mutual discharge at low temperatures when the battery is used in parallel, and achieving effective utilization of battery power.

CN222884374UActive Publication Date: 2025-05-16SHANGHAI PYTES ENERGY CO LTD

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Patent Information

Application Number: CN202421774693.5
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-07-25
Publication Date: 2025-05-16
Estimated Expiration: 2034-07-25

AI Technical Summary

Technical Problem

When batteries are used in parallel, the problem of discharge between batteries at low temperatures leads to excessive power consumption.

Method used

A battery parallel low-temperature protection circuit suitable for negative electrode charging protection system is designed. Through the combination of microprocessor chip, external power supply, specific MOS tube and photocoupler, the heating film is controlled to ensure that heating is only turned on when the external power supply voltage is higher than a certain value of the battery voltage, and avoid mutual discharge between batteries.

Benefits of technology

It effectively avoids the problem of mutual discharge at low temperatures when batteries are connected in parallel, ensures the effective utilization of battery power, and consumes battery capacity only when necessary.

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Abstract

The utility model relates to the technical field of battery protection circuits, in particular to a battery parallel low-temperature protection circuit suitable for a cathode charging protection system. A battery parallel low-temperature protection circuit suitable for a cathode charging protection system is characterized in that a battery cathode interface is respectively connected with one end of a first current-limiting resistor and a drain electrode of a first MOS tube, the other end of the first current-limiting resistor is connected with an anode of a photoelectric coupler, and a cathode of the photoelectric coupler is connected with an anode of a diode; and an emitting electrode of the photoelectric coupler is respectively connected with a source electrode of the second MOS tube, one end of the filter capacitor and a battery cathode interface. Compared with the prior art, when the voltage of the external power supply is higher than a certain value of the voltage of the batteries, it is considered that the external power supply is connected, a DCIN signal is added into a judgment condition for starting the heating film, and even if the voltage difference between the batteries is higher than a set value and the heating film is started, only a small part of capacity is consumed, and the electric quantity of the batteries cannot be consumed any more.

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Description

Technical Field

[0001] The utility model relates to the technical field of battery protection circuits, in particular to a battery parallel low-temperature protection circuit suitable for a negative electrode charging protection system. Background Art

[0002] 70% of the capacity of the energy storage battery is in the voltage plateau period, that is, the voltage is almost unchanged. The energy storage battery cannot be charged but can be discharged when it is below zero degrees. However, there is a market demand for use below zero degrees, so a heating function is added to the energy storage battery. The battery is heated to a temperature above zero before use. The heating film is powered by an external power supply. Otherwise, leaving the battery at low temperature will consume the battery power. Therefore, one of the conditions for turning on the heating is that the external power supply is in place. In actual applications, many energy storage batteries will be used in parallel to achieve the purpose of capacity expansion.

[0003] Defects and deficiencies in practical applications: The battery has a heating function. Multiple (2 or more) batteries are connected in parallel and left to stand at a low temperature (the temperature required to turn on the heating). Assuming that the voltage of battery A is higher than that of battery B, battery A is equivalent to the external power supply of battery B, and battery A will supply power to the heating film of battery B; when the voltage of battery A is lower than that of battery B, and the heating of battery B is finished, battery B is equivalent to the external power supply of battery A, and battery B will supply power to the heating film of battery A. In this way, the power of battery A and battery B will be consumed by the heating film. Summary of the invention

[0004] The utility model overcomes the shortcomings of the prior art and provides a battery parallel low temperature protection circuit suitable for a negative electrode charging protection system, which solves the problem of mutual discharge of batteries in parallel at low temperatures at a low cost.

[0005] To achieve the above purpose, a battery parallel low-temperature protection circuit suitable for a negative electrode charging protection system is designed, comprising a microprocessor chip and an external power supply, characterized in that: the battery negative electrode interface is respectively connected to one end of a first current limiting resistor and a drain electrode of a first MOS tube, the other end of the first current limiting resistor is connected to the positive electrode of a photoelectric coupler, the negative electrode of the photoelectric coupler is connected to the anode of a diode, the emitter of the photoelectric coupler is respectively connected to the source of a second MOS tube, one end of a filter capacitor, and the battery negative electrode interface; the collector of the photoelectric coupler is respectively connected to one end of a second current limiting resistor and a gate of a second MOS tube, and the second MO The drain electrode of the S tube is respectively connected to one end of the third current limiting resistor, the other end of the filter capacitor, and port 5 of the microprocessor chip; the other end of the second current limiting resistor and the other end of the third current limiting resistor are combined and connected to the VCC power supply; port 6 of the microprocessor chip is respectively connected to the gate of the third MOS tube and one end of the voltage dividing resistor, and the source of the third MOS tube is respectively connected to the other end of the voltage dividing resistor, the cathode of the diode, the source of the first MOS tube, and the negative electrode interface of the external power supply; the drain electrode of the third MOS tube is connected to one end of the heating resistor, and the other end of the heating resistor is respectively connected to the positive electrode interface of the battery and the positive electrode interface of the external power supply.

[0006] Port No. 5 of the microprocessor chip is connected to an external power supply presence detection signal.

[0007] Port No. 6 of the microprocessor chip is connected to the heating enable signal.

[0008] The microprocessor chip is provided with a plurality of IO interfaces, and the microprocessor chip is a stm32 series microprocessor chip.

[0009] The second MOS tube and the third MOS tube are MOS power tubes or triodes.

[0010] The third MOS tube is a heating control MOS tube.

[0011] The first MOS tube is a MOS power tube or a contactor.

[0012] The first MOS tube is a charging protection device.

[0013] The photoelectric coupler is a photoelectric coupler or a relay.

[0014] Compared with the prior art, the utility model provides a battery parallel low-temperature protection circuit suitable for a negative electrode charging protection system. When the external power supply voltage is higher than a certain value of the battery voltage, it is considered that the external power supply is connected, and a DCIN signal is added to the judgment condition for turning on the heating film. When the batteries are connected in parallel, the heating film will not be turned on if the voltage difference between the batteries is lower than the set value, and they will not discharge each other at this time. Since most of the capacity of the energy storage battery is in the voltage platform period, that is, the voltage change is very small, even if the voltage difference between the batteries is higher than the set value and the heating film is turned on, only a small part of the capacity will be consumed and the battery power will not continue to be consumed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the circuit connection of the utility model. DETAILED DESCRIPTION

[0016] The utility model is further described below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, the battery negative electrode interface BAT- is respectively connected to one end of the first current limiting resistor R1 and the drain electrode of the first MOS tube Q2, the other end of the first current limiting resistor R1 is connected to the positive electrode of the photoelectric coupler U1, the negative electrode of the photoelectric coupler U1 is connected to the anode of the diode D1, the emitter of the photoelectric coupler U1 is respectively connected to the source of the second MOS tube Q1, one end of the filter capacitor C1, and the battery negative electrode interface BAT-; the collector of the photoelectric coupler U1 is respectively connected to one end of the second current limiting resistor R2 and the gate of the second MOS tube Q1, the drain electrode of the second MOS tube Q1 is respectively connected to one end of the third current limiting resistor R3 and the other end of the filter capacitor C1. One end of the second current limiting resistor R2 and the other end of the third current limiting resistor R3 are combined and connected to the VCC power supply; the No. 6 port of the microprocessor chip U2 is respectively connected to the gate of the third MOS tube Q3 and one end of the voltage dividing resistor R4, and the source of the third MOS tube Q3 is respectively connected to the other end of the voltage dividing resistor R4, the cathode of the diode D1, the source of the first MOS tube Q2, and the external power supply negative electrode interface PACK-; the drain electrode of the third MOS tube Q3 is connected to one end of the heating resistor R5, and the other end of the heating resistor R5 is respectively connected to the battery positive electrode interface BAT+ and the external power supply positive electrode interface PACK+.

[0018] Port 5 of the microprocessor chip U2 is connected to an external power supply presence detection signal.

[0019] Port 6 of the microprocessor chip U2 is connected to the heating enable signal.

[0020] The microprocessor chip U2 is provided with a plurality of IO interfaces, and the microprocessor chip U2 is a stm32 series microprocessor chip.

[0021] The second MOS tube Q1 and the third MOS tube Q3 are MOS power tubes or triodes.

[0022] The third MOS tube Q3 is a heating control MOS tube.

[0023] The first MOS tube Q2 is a MOS power tube or a contactor.

[0024] The first MOS tube Q2 is a charging protection device.

[0025] The photocoupler U1 is a photocoupler or a relay.

[0026] like Figure 1 As shown, the utility model adopts a battery system with negative charging protection. BAT+ is the positive electrode interface of the battery, BAT- is the negative electrode interface of the battery, PACK+ is the positive electrode interface of the external power supply, and PACK- is the negative electrode interface of the external power supply. When the batteries are connected in parallel, the PACK+ of all the batteries are connected together, and the PACK- of all the batteries are connected together. VCC is the output voltage of the battery voltage after passing through the power chip, which is connected to port 5 of the microprocessor chip U2. HEATEN is the heating enable signal, which is connected to port 6 of the microprocessor chip U2. The first current limiting resistor R1 prevents the voltage difference between the battery negative electrode interface BAT- and the external power supply negative electrode interface PACK- from being too large, resulting in excessive current and damaging the photocoupler U1. The photocoupler U1 is an optocoupler or a relay, which is used as an isolating switch. The microprocessor chip U2 is an MCU, that is, a circuit board microprocessor. The diode D1 prevents the photocoupler U1 from being damaged when the voltage of the external power supply negative electrode interface PACK- is greater than the voltage of the battery negative electrode interface BAT-. The second current limiting resistor The resistor R2 prevents the photocoupler U1 from being turned on and the current flowing through the emitter and collector of the photocoupler U1 is too large, thereby damaging the photocoupler U1. The second MOS tube Q1 is a MOS tube or a triode. The third current limiting resistor R3 prevents the second MOS tube Q1 from being turned on and the current flowing through the source and drain electrodes of the second MOS tube Q1 is too large, thereby damaging the second MOS tube Q1. The filter capacitor C1 and the third current limiting resistor R3 form a filter circuit to filter out part of the DCIN interference signal. The first MOS tube Q2 is a charging protection device, which can be a MOS or a contactor, etc. The third MOS tube Q3 is a heating control MOS tube to control whether the heating circuit is turned on. The heating resistor R5 is a heating film used to heat the battery. R4 is a voltage divider resistor to maintain the HEATEN level.

[0027] When the first MOS tube Q2 is turned on, the battery is directly connected to the external power supply and can be charged and discharged; when the first MOS tube Q2 is turned off, the external power supply cannot charge the battery, so the first MOS tube Q2 is a charging protection device.

[0028] When the external power supply voltage is not higher than a certain value of the battery voltage (here, 1.5V is taken as an example, and this value is jointly determined by the first current limiting resistor R1, the photocoupler U1, and the diode D1, and is calculated by multiplying the first current limiting resistor R1 by the on-current of the photocoupler U1 plus the on-voltage of the photocoupler U1 plus the on-voltage of the diode D1) or the first MOS tube Q2 is turned on, the photocoupler U1 is in a non-conducting state, that is, the emitter and collector of the photocoupler U1 are in a disconnected state. At this time, the gate voltage of the second MOS tube Q1 is VCC, the source voltage of the second MOS tube Q1 is 0V, the GS voltage of the second MOS tube Q1 is VCC, the source and drain electrodes of the second MOS tube Q1 are turned on, and the DCIN signal is connected to 0V through the source and drain electrodes of the second MOS tube Q1. When the microprocessor chip U2 detects that the DCIN signal is 0V, it will pull down the HEATEN signal, and the GS voltage of the third MOS tube Q3 is 0V, and the third MOS tube Q3 is disconnected, thereby disconnecting the heating circuit or keeping the heating circuit disconnected; when the external power supply voltage is not higher than a certain value of the battery voltage (here, 1.5V is taken as an example, and this value is jointly determined by the first current limiting resistor R1, the photocoupler U1, and the diode D1, and the diode D1 is jointly determined by the first current limiting resistor R1, and the photocoupler U1 is in a non-conducting state, that is, the emitter and collector of the photocoupler U1 are in a disconnected state, and the gate voltage of the second MOS tube Q1 is VCC, the source voltage of the second MOS tube Q1 is 0V, the GS voltage of the second MOS tube Q1 is VCC, the source and drain electrodes of the second MOS tube Q1 are turned on, and the When the power supply voltage is higher than a certain value of the battery voltage (here taking 1.5V as an example, the first current limiting resistor R1, the photocoupler U1, and the diode D1 jointly determine it, which is calculated by multiplying the first current limiting resistor R1 by the on-current of the photocoupler U1 plus the on-voltage of the photocoupler U1 plus the on-voltage of the diode D1) and the first MOS tube Q2 is disconnected, the photocoupler U1 is in the on-state, that is, the emitter and collector of the photocoupler U1 are in the on-state, at this time, the gate voltage of the second MOS tube Q1 is 0V, the source voltage of the second MOS tube Q1 is 0V, the GS voltage of the second MOS tube Q1 is 0V, the source and drain electrodes of the second MOS tube Q1 are disconnected, the DCIN signal is connected to VCC through the third current limiting resistor R3, and when the microprocessor chip U2 detects that the DCIN signal is VCC and other conditions for starting heating are met, the HEATEN signal will be pulled high, the GS voltage of the third MOS tube Q3 is the on-voltage, and the third MOS tube Q3 is turned on, thereby turning on the heating circuit or keeping the heating circuit turned on.

[0029] The utility model considers that the external power supply is connected only when the voltage of the external power supply is higher than a certain value of the battery voltage, and adds the DCIN signal to the judgment condition for turning on the heating film. When the batteries are connected in parallel, the heating film will not be turned on if the voltage difference between the batteries is lower than the set value, and they will not discharge each other at this time. Since most of the capacity of the energy storage battery is in the voltage plateau period, that is, the voltage changes very little, even if the voltage difference between the batteries is higher than the set value and the heating film is turned on, only a small part of the capacity will be consumed and the battery power will not continue to be consumed.

Claims

1. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system, comprising a microprocessor chip and an external power supply, characterized in that: The battery negative electrode interface (BAT-) is respectively connected to one end of the first current limiting resistor (R1) and the drain electrode of the first MOS tube (Q2); the other end of the first current limiting resistor (R1) is connected to the positive electrode of the photoelectric coupler (U1); the negative electrode of the photoelectric coupler (U1) is connected to the anode of the diode (D1); the emitter of the photoelectric coupler (U1) is respectively connected to the source of the second MOS tube (Q1), one end of the filter capacitor (C1), and the battery negative electrode interface (BAT-); the collector of the photoelectric coupler (U1) is respectively connected to one end of the second current limiting resistor (R2) and the gate of the second MOS tube (Q1); the drain electrode of the second MOS tube (Q1) is respectively connected to one end of the third current limiting resistor (R3), the other end of the filter capacitor (C1), and the collector of the photoelectric coupler (U1). The first MOS tube (Q3) is connected to a first MOS tube (Q4) and a second MOS tube (Q5) connected to a first MOS tube (Q6) and a second MOS tube (Q7) connected to a first MOS tube (Q8) and a second MOS tube (Q9) connected to a first MOS tube (Q10) and a second MOS tube (Q11) connected to a second MOS tube (Q12) and a second MOS tube (Q13) connected to a first MOS tube (Q14) and a second MOS tube (Q20) connected to a first MOS tube (Q21) and a second MOS tube (Q30) connected to a first MOS tube (Q15) and a second MOS tube (Q20) connected to a first MOS tube (Q16) and a second MOS tube (Q20) connected to a second MOS tube (Q17) and a second MOS tube (Q20) connected to a first MOS tube (Q18) and a second MOS tube (Q20) connected to a first MOS tube (Q19) and a second MOS tube (Q20) connected to a second MOS tube (Q19) and a second MOS tube (Q20) connected to a first MOS tube (Q11) and a second MOS tube (Q20) connected to a first MOS tube (Q12) and a second MOS tube (Q20) connected to a second MOS tube (Q13) and a second MOS tube (Q14) connected to a first MOS tube (Q15) and a second MOS tube (Q20) connected to a first MOS tube (Q16) and a second MOS tube (Q17) connected to a first MOS tube (Q18) and a second MOS tube (Q19) connected to a first MOS tube (Q19) and a second MOS tube (Q19) connected to a first MOS tube (Q19) and a second MOS tube (Q19) connected to a first MOS tube (Q11) and a second MOS tube (Q19) connected 2. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, characterized in that: Port 5 of the microprocessor chip (U2) is connected to an external power supply presence detection signal.

3. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, characterized in that: Port 6 of the microprocessor chip (U2) is connected to the heating enable signal.

4. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, 2 or 3, characterized in that: The microprocessor chip (U2) is provided with a plurality of IO interfaces, and the microprocessor chip (U2) is a stm32 series microprocessor chip.

5. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, characterized in that: The second MOS tube (Q1) and the third MOS tube (Q3) are MOS power tubes or triodes.

6. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1 or 5, characterized in that: The third MOS tube (Q3) is a heating control MOS tube.

7. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, characterized in that: The first MOS tube (Q2) is a MOS power tube or a contactor.

8. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1 or 7, characterized in that: The first MOS tube (Q2) is a charging protection device.

9. A battery parallel low temperature protection circuit suitable for a negative electrode charging protection system according to claim 1, characterized in that: The photoelectric coupler (U1) is a photoelectric coupler or a relay.