A heating control circuit for a battery management system

Abstract

The utility model discloses a kind of heating control circuit of battery management system, including battery microprocessor, heating switch control circuit, heating switch and battery pack output end negative pole connected in turn;Battery microprocessor is also respectively connected with charger detection circuit and hall current acquisition circuit, the heating switch control circuit is also connected with the hall current acquisition circuit;Three-terminal fuse is connected between the hall current acquisition circuit and battery pack positive pole / charger positive pole, and three-terminal fuse control circuit is connected between three-terminal fuse and battery microprocessor. Utilize the heating control circuit provided by the utility model, can greatly protect the heating safety of battery, avoid the occurrence of safety accident caused by heating failure in some specific conditions, such as can effectively prevent the possible circuit short circuit, battery overheating or even thermal runaway etc. safety hazard caused by charger reverse connection.

Description

Technical Field

[0001] This utility model relates to the field of battery management system technology, and specifically to a heating control circuit for a battery management system. Background Technology

[0002] Lithium-ion batteries suffer from reduced activity and increased internal resistance at low temperatures, leading to a significant decline in discharge performance and severely limiting their application in cold regions. Therefore, battery management systems (BMS) typically require heating methods to raise the battery temperature and restore performance.

[0003] Traditional heating solutions typically use a BMS current sampling circuit (such as a sampling resistor or operational amplifier) ​​to collect the current signal of the heating circuit and control the heating power accordingly. However, this solution has the following drawbacks:

[0004] (1) Control logic conflict when the charger is connected: When an external charger is connected, the system stops collecting heating current by default and only relies on the charger to charge the battery, which forces the heating function to be turned off. This not only reduces the charging efficiency in low temperature environments, but may also cause charging abnormalities due to insufficient battery temperature.

[0005] (2) Safety risks when the charger is reversed: If the charger polarity is accidentally reversed, traditional solutions may misjudge it as a normal charging state due to the lack of an independent detection mechanism, causing the heating circuit to continue to work. At this time, the superposition of the reversed charger and the heating current may cause a short circuit, battery overheating or even thermal runaway, which poses a serious safety hazard.

[0006] Therefore, existing heating solutions are inadequate in terms of safety and urgently need improvement. Utility Model Content

[0007] The purpose of this invention is to provide a heating control circuit for a battery management system to solve at least one technical problem in the prior art.

[0008] The technical solution provided by this utility model is as follows:

[0009] A heating control circuit for a battery management system includes a battery microprocessor, a heating switch control circuit, a heating switch, and a negative terminal of the battery pack connected in sequence.

[0010] The battery microprocessor is also connected to a charger detection circuit and a Hall current acquisition circuit, and the heating switch control circuit is also connected to the Hall current acquisition circuit.

[0011] The Hall current acquisition circuit is connected to the positive terminal of the battery pack / charger via a three-terminal fuse, and a three-terminal fuse control circuit is connected between the three-terminal fuse and the battery microprocessor.

[0012] Furthermore, a charger reverse connection protection circuit is connected between the heating switch control circuit and the heating switch.

[0013] Specifically, the reverse connection protection circuit of the charger includes a transistor HR2 and a Zener diode HZ3. The emitter and collector of the transistor HR2 are both connected to the heating switch control circuit. The base of the transistor HR2 is connected to the emitter of the transistor HR2 and the cathode of the Zener diode HZ3 through resistors. The anode of the Zener diode HZ3 is connected to the negative terminal of the battery pack output.

[0014] Furthermore, a temperature switch is provided between the positive terminal of the battery pack / charger and the three-terminal fuse.

[0015] Preferably, the Hall current acquisition circuit includes a Hall current acquisition chip, a Hall chip power control circuit, and a current acquisition output circuit. The Hall chip power control circuit is connected to both the Hall current acquisition chip and the heating switch control circuit. The current acquisition output circuit is connected between the battery microprocessor and the Hall current acquisition chip.

[0016] Preferably, the Hall chip power control circuit includes a field-effect transistor switching control circuit.

[0017] Preferably, the Hall current acquisition chip is model CC6937.

[0018] Preferably, the heating switch control circuit includes two or more transistor switch control circuits.

[0019] Preferably, the heating switch is a field-effect transistor switch.

[0020] Preferably, the three-terminal fuse control circuit includes one or more field-effect transistor switch control circuits, and / or

[0021] The charger detection circuit includes a transistor switch control circuit.

[0022] Compared with the prior art, the heating control circuit provided by this utility model has the following beneficial effects:

[0023] Applying the aforementioned heating control circuit to the battery management system can greatly protect the heating safety of the battery and avoid safety accidents caused by heating failure in certain situations. For example, it can effectively prevent safety hazards such as short circuits, battery overheating, or even thermal runaway caused by reverse connection of the charger. In addition, the control circuit can use the battery's electrical energy to heat the battery, or it can use the charger's electrical energy to heat the battery, thereby effectively improving charging efficiency in low-temperature environments and effectively preventing charging abnormalities caused by insufficient battery temperature. Attached Figure Description

[0024] Figure 1 A schematic block diagram of the heating control circuit described in this embodiment of the present invention;

[0025] Figure 2 This is a detailed circuit diagram of the heating control circuit described in the embodiments of this utility model;

[0026] Figure 3 This is a detailed circuit diagram of the heating switch control circuit, the heating switch, and the charger reverse connection protection circuit described in this embodiment of the utility model.

[0027] Figure 4 This is a detailed circuit diagram of the Hall current acquisition circuit described in the embodiments of this utility model;

[0028] Figure 5 This is a detailed circuit diagram of the three-terminal fuse control circuit, the three-terminal fuse, and the temperature switch described in this embodiment of the utility model.

[0029] Figure 6 This is a detailed circuit diagram of the charger detection circuit described in this embodiment of the present invention.

[0030] The attached diagrams are labeled as follows: 10. Heating switch control circuit; 11. Heating switch; 20. Charger reverse connection protection circuit; 30. Hall current acquisition circuit; 31. Hall current acquisition chip; 32. Hall chip power control circuit; 33. Current acquisition output circuit; 40. Three-terminal fuse control circuit; 50. Three-terminal fuse; 60. Charger detection circuit; 70. Temperature switch. Detailed Implementation

[0031] To better understand the purpose, technical solution, and technical effects of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will provide further explanation. It should also be stated that the embodiments described below are for illustrative purposes only and are not intended to limit the scope of this utility model. Example

[0032] like Figure 1 As shown, a heating control circuit for a battery management system includes a battery microprocessor, a heating switch control circuit, a heating switch, and a negative terminal of the battery pack connected in sequence.

[0033] The battery microprocessor is also connected to a charger detection circuit and a Hall current acquisition circuit, and the heating switch control circuit is also connected to the Hall current acquisition circuit.

[0034] The Hall current acquisition circuit is connected to the positive terminal of the battery pack / charger via a three-terminal fuse, and a three-terminal fuse control circuit is connected between the three-terminal fuse and the battery microprocessor.

[0035] In a preferred embodiment, the heating switch is a field-effect transistor switch; the heating switch control circuit includes two or more transistor switch control circuits; the three-terminal fuse control circuit includes one or more field-effect transistor switch control circuits; and the charger detection circuit includes a transistor switch control circuit.

[0036] In a preferred embodiment, the Hall current acquisition circuit includes a Hall current acquisition chip, a Hall chip power control circuit, and a current acquisition output circuit. The Hall chip power control circuit is connected to both the Hall current acquisition chip and the heating switch control circuit. The current acquisition output circuit is connected between the battery microprocessor and the Hall current acquisition chip. Preferably, the Hall chip power control circuit includes a field-effect transistor switch control circuit; the Hall current acquisition chip is a CC6937.

[0037] In this embodiment, the Hall current acquisition circuit is used to acquire the heating current and transmit the acquired heating current to the battery microprocessor for processing. The charger detection circuit is used to detect whether the charger is connected, so that the battery microprocessor outputs a corresponding switch signal to control the heating switch control circuit to turn the heating switch on or off. When the battery microprocessor detects that the heating current can still be greater than a preset value after the heating switch is turned off, the battery microprocessor outputs a corresponding control signal (switch signal) to control the three-terminal fuse control circuit, so that the three-terminal fuse burns out, thereby effectively protecting the safety of the entire heating control circuit.

[0038] In a preferred embodiment, a charger reverse connection protection circuit is connected between the heating switch control circuit and the heating switch.

[0039] By setting up the reverse connection protection circuit of the charger, when the reverse connection of the charger is detected, the reverse connection protection circuit outputs a corresponding switch signal to turn off the heating switch, thereby effectively avoiding safety hazards such as short circuit, battery overheating or even thermal runaway that may be caused by the reverse connection of the charger.

[0040] In a preferred embodiment, a temperature switch is provided between the positive terminal of the battery pack / charger and the three-terminal fuse.

[0041] By setting a temperature switch, the circuit will be cut off when the temperature of the circuit exceeds the safety threshold, which can effectively prevent the circuit or battery from overheating and causing thermal runaway.

[0042] The following describes the patent application solution in detail with specific embodiments. The specific circuit of the heating control circuit in this embodiment is shown in the attached figure. Figures 2-6 As shown. In this specific embodiment, the battery microprocessor is omitted. (See attached diagram.) Figures 2-6In this circuit, BATT+ is the positive terminal of the battery pack or the positive terminal of the charger; HP is the positive terminal of the heating port; C- is the negative terminal of the battery pack output; HM1 and HM2 are heating switches; HU1 is a Hall current detection chip; HF2 is a three-terminal fuse; HPTC1 is a temperature switch; S_HCP is the battery microprocessor control pin of the three-terminal fuse; WK_CHG is the charger detection pin of the battery microprocessor; HC_EN is the heating control pin of the battery microprocessor; VREG is the system voltage, typically 3.3V. It should be noted that the heating control circuit in this patent application is based on a protection scheme for the negative terminal of the battery, meaning the protection switch is connected to the negative terminal of the battery.

[0043] Specifically, as shown in the attached document Figure 3 As shown, the reverse connection protection circuit 20 of the charger includes a transistor HR2 and a Zener diode HZ3. The emitter (E) and collector (C) terminals of transistor HR2 are both connected to the heating switch control circuit 10. The base (B) terminal of transistor HR2 is connected to both the emitter (E) terminal of transistor HR2 and the cathode of Zener diode HZ3 via resistors. The anode of Zener diode HZ3 is connected to the negative terminal of the battery pack output. The specific circuit composition and connections are shown in the attached figure. Figure 3 As shown. The heating switches 11 are field-effect transistor switches HM1 and HM2.

[0044] The heating switch control circuit 10 includes transistors HQ1, HQ2, and HQ3, diodes HD1 and HD4, and Zener diodes HZ2 and HZ1. The specific circuit composition and connection relationships of the heating switch control circuit are shown in the attached figure. Figure 3 As shown, it will not be elaborated further here.

[0045] Details are as attached Figure 4 As shown, the Hall current acquisition circuit 30 includes a Hall current acquisition chip 31, a Hall chip power control circuit 32, and a current acquisition output circuit 33. In this embodiment, the Hall current acquisition chip is a CC6937, and the Hall chip power control circuit 32 mainly includes a MOSFET HX1 and a diode HD5. The specific composition and connection relationship are shown in the attached figure. Figure 4 As shown, it will not be elaborated further here.

[0046] Details are as attached Figure 5 As shown, the three-terminal fuse control circuit 40 includes MOSFETs HM3 and HM4, Zener diodes HZ4, HZ5, and HD2, etc. The specific components and connections are shown in the attached figure. Figure 5 As shown, it will not be elaborated further here.

[0047] Details are as attached Figure 6As shown, the charger detection circuit 60 includes transistor EQ1, diodes ED1, ED2, and ED3, etc., and their specific components and connections are shown in the attached figure. Figure 6 As shown, it will not be elaborated further here.

[0048] The following is a brief description of the working process or working principle of the heating control circuit provided in this embodiment:

[0049] As attached Figures 1-6 As shown, when the battery microprocessor controls the HC_EN pin to be high, heating switches HM1 and HM2 are turned on. At this time, the power supply to the Hall current detection chip HU1 is also normally conducted. The heating current flows from the positive terminal HP of the heating port, through the three-terminal fuse HF2, the Hall current detection chip HU1, heating switch HM2, and back to the negative terminal C- of the battery pack output. After the signal from the Hall current acquisition circuit is processed by the battery microprocessor, the heating current information can be obtained. If the heating current is detected to be too large or the temperature of the heating cell is detected to be too high, the battery microprocessor will turn off heating switches HM1 and HM2. If the heating current is still detected to be greater than a certain value after heating switches HM1 and HM2 are turned off, it can be considered that the control switches of heating switches HM1 and HM2 have failed. At this time, the battery microprocessor can control the control pin S_HCP of the three-terminal fuse to output a high level, causing the three-terminal fuse HF2 to burn out, thereby ensuring the safety of the circuit.

[0050] When the battery discharge MOSFET is off, and heating is required using a charger, if the charger's power is less than the heating circuit's power, the voltage of the entire heating circuit will be pulled down. After a certain point, the driving voltage of the heating MOSFET will also be pulled down, causing the MOSFET to operate in the variable resistance region, potentially burning it out. Therefore, in existing technologies, to prevent MOSFET burnout, the battery management system defaults to stopping the collection of heating current when an external charger is connected, relying solely on the charger to charge the battery, thus forcibly shutting down the heating function. In other words, existing technologies cannot use the charger's power to heat the battery. In this patented solution, to utilize the charger's power for battery heating, a charger detection circuit is added. The battery microprocessor can detect whether the charging voltage is pulled down through the charger detection pin WK_CHG. When a low charger voltage is detected during heating, the battery microprocessor will not detect a high-level input to WK_CHG, at which point it can turn off the heating MOSFET. Therefore, by adding a charger detection circuit in this solution, there is no risk of burning out the MOSFET when the charger is used for heating. In summary, the heating control circuit provided by this patent solution can heat the battery using either the battery's electrical energy or the charger's electrical energy, thereby effectively improving charging efficiency in low-temperature environments and effectively avoiding charging abnormalities caused by insufficient battery temperature.

[0051] When the charger's reverse connection protection circuit detects that the charger has been accidentally connected in reverse, the presence of transistor HR2 can shut down the heating switch control circuit, thereby immediately stopping the heating. This effectively avoids the safety hazards that may be caused by the superposition of reverse connection of electrical appliances and heating current, such as short circuit, battery overheating, or even thermal runaway.

[0052] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A heating control circuit of a battery management system, characterized by, It includes a battery microprocessor, a heating switch control circuit, a heating switch, and the negative terminal of the battery pack output, which are connected in sequence. The battery microprocessor is also connected to a charger detection circuit and a Hall current acquisition circuit, and the heating switch control circuit is also connected to the Hall current acquisition circuit. The Hall current acquisition circuit is connected to the positive terminal of the battery pack / charger via a three-terminal fuse, and a three-terminal fuse control circuit is connected between the three-terminal fuse and the battery microprocessor.

2. The heating control circuit of claim 1, wherein, A charger reverse connection protection circuit is connected between the heating switch control circuit and the heating switch.

3. The heating control circuit of claim 2, wherein, The reverse connection protection circuit of the charger includes a transistor HR2 and a Zener diode HZ3. The emitter and collector of transistor HR2 are both connected to the heating switch control circuit. The base of transistor HR2 is connected to the emitter of transistor HR2 and the cathode of Zener diode HZ3 through resistors. The anode of Zener diode HZ3 is connected to the negative terminal of the battery pack output.

4. The heating control circuit of claim 1, wherein, A temperature switch is installed between the positive terminal of the battery pack / charger and the three-terminal fuse.

5. The heating control circuit of claim 1, wherein, The Hall current acquisition circuit includes a Hall current acquisition chip, a Hall chip power control circuit, and a current acquisition output circuit. The Hall chip power control circuit is connected to both the Hall current acquisition chip and the heating switch control circuit. The current acquisition output circuit is connected between the battery microprocessor and the Hall current acquisition chip.

6. The heating control circuit according to claim 5, characterized in that, The Hall chip power control circuit includes a field-effect transistor switching control circuit.

7. The heating control circuit according to claim 1, characterized in that, The Hall current acquisition chip is model CC6937.

8. The heating control circuit according to claim 1, characterized in that, The heating switch control circuit includes two or more transistor switch control circuits.

9. The heating control circuit according to claim 1, characterized in that, The heating switch is a field-effect transistor switch.

10. The heating control circuit according to claim 1, characterized in that, The three-terminal fuse control circuit includes one or more field-effect transistor switching control circuits, and / or The charger detection circuit includes a transistor switch control circuit.

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