Lithium battery charging and discharging loop control circuit
By designing the lithium battery charge and discharge circuit control circuit, and using the voltage comparator and logic gate circuit to independently control the charge and discharge function, the complex problem of charging and discharge circuit design in the existing technology is solved, and independent control and safety improvement is achieved.
Patent Information
- Application Number
- CN202422135620.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-09-02
AI Technical Summary
The charging and discharging circuit design of lithium batteries in existing BMS systems cannot be independently controlled, resulting in complex control functions or defects.
A lithium battery charge and discharge circuit control circuit is designed to realize independent control of charge and discharge functions through voltage comparator and logic gate circuit, and the MCU's GPIO port outputs control signals to manage the charge and discharge circuit.
Without increasing costs, independent control of charge and discharge functions is achieved, the control logic of the BMS system is simplified, and the safety and efficiency of the battery are improved.
Smart Images
Figure CN223168057U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium batteries, and specifically relates to a control circuit for a lithium battery charge and discharge circuit. Background Art
[0002] Nowadays, there are mainly two types of energy storage batteries used in the new energy market. One is the ternary battery, and the other is the lithium iron phosphate battery. The ternary battery has a high density, a large unit electric energy, and a strong endurance ability. However, its stability is poor, and the ignition point is relatively low when it is impacted or at high temperature. Compared with the ternary battery, the lithium iron phosphate battery has been continuously improved, with more stable safety, a cycle life that can reach more than 6,000 times, high temperature resistance, and no environmental pollution. In recent years, the Chinese government has clear goals for energy conservation and emissions reduction and strongly supports it. Therefore, the lithium iron phosphate battery is the most ideal power battery so far. It can not only be used as the power battery of electric vehicles but also be used as power storage in combination with secondary energy sources such as solar energy and wind energy.
[0003] In use, when users use electrical energy, they need to discharge the battery, and when the battery power is low, they need to charge the battery. During the entire life cycle of the battery, its actual use state is dynamically cycled between charging and discharging. Lithium batteries generally manage and control the charge and discharge state of the battery through the BMS system. At the same time, the BMS system is also part of the lithium battery safety and protection system. When using a lithium battery, once factors such as overvoltage, undervoltage, overheating, and underheating that may pose a danger to the safety of the lithium battery occur, on the one hand, the BMS system should be able to control the battery to stop charging or discharging to ensure the safety of the battery. On the other hand, it should not affect the normal use of the battery as much as possible. For example, when the battery voltage is too high, the BMS should prohibit charging the battery but allow the battery to discharge. Conversely, when the battery voltage is too low or the battery power is insufficient, the battery should be prohibited from discharging, but charging the battery should be allowed.
[0004] To achieve the above goals, the charge and discharge circuits in the BMS system should be as independent as possible, that is, the control of the charging and discharging functions of the battery does not affect each other. However, in the current actual application of the BMS system, the design of the charge and discharge circuits generally cannot be completely independently controlled, resulting in too complex control functions of the BMS or application defects. Summary of the Invention
[0005] The utility model aims to overcome the deficiencies of the prior art and provides a control circuit for a lithium battery charge and discharge circuit, which can realize the independent control ability of the charge and discharge functions on the premise of not increasing the cost as much as possible.
[0006] To achieve the above object, a control circuit for a lithium battery charge and discharge circuit is designed, including a PACK terminal, a battery terminal, and an MCU. It is characterized in that: the voltage input signals of the PACK terminal and the battery terminal are respectively connected to the input terminals of a voltage comparator, and the output terminal of the voltage comparator is respectively connected to the input terminal of an inverter and the input terminal A of a first AND gate; the output terminal of the inverter is connected to the input terminal A of a second AND gate, the input terminal B of the second AND gate is connected to the discharge control signal terminal of the MCU, and the output terminal of the second AND gate is connected to one end of a first switch. The other end of the first switch is respectively connected to one end of a second switch and the discharge circuit of the battery terminal; the other end of the second switch is respectively connected to the output terminal of the first AND gate and the charging circuit of the battery terminal; the input terminal B of the first AND gate is connected to the charging control signal terminal of the MCU.
[0007] A PACK terminal is connected between the other end of the first switch and one end of the second switch.
[0008] The MCU is an embedded chip, and the model of the MCU is one of the STM32 series of STMicroelectronics and the GD32 series of GigaDevice Semiconductor Inc.
[0009] The discharge control signal terminal and the charging control signal terminal of the MCU are output by GPIO ports.
[0010] The first switch and the second switch are MOS field effect transistors or contactors.
[0011] Compared with the prior art, the present invention provides a control circuit for a lithium battery charge and discharge circuit, which realizes the independent control ability of the charge and discharge functions on the premise of minimizing cost increase. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a circuit diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0013] The following further describes the present invention with reference to the drawings.
[0014] As Figure 1As shown, the voltage input signal VP of the PACK terminal P and the voltage input signal VB of the battery terminal B are respectively connected to the input terminals of the voltage comparator U. The output terminal of the voltage comparator U is respectively connected to the input terminal of the inverter N and the input terminal A of the first AND gate Y2. The output terminal of the inverter N is connected to the input terminal A of the second AND gate Y1. The input terminal B of the second AND gate Y1 is connected to the discharge control signal terminal of the MCU. The output terminal of the second AND gate Y1 is connected to one end of the first switch K1. The other end of the first switch K1 is respectively connected to one end of the second switch K2 and the discharge circuit of the battery terminal B. The other end of the second switch K2 is respectively connected to the output terminal of the first AND gate Y2 and the charging circuit of the battery terminal B. The input terminal B of the first AND gate Y2 is connected to the charging control signal terminal of the MCU.
[0015] A PACK terminal P is connected between the other end of the first switch K1 and one end of the second switch K2.
[0016] The MCU is an embedded chip, and the model of the MCU is one of the STM32 series of STMicroelectronics and the GD32 series of GigaDevice Semiconductor Inc.
[0017] The discharge control signal terminal and the charging control signal terminal of the MCU are output by GPIO ports.
[0018] The first switch K1 and the second switch K2 are MOS field effect transistors or contactors.
[0019] The MCU generally uses an embedded processing chip, and mainstream embedded chips on the market, such as the STM32 series of STMicroelectronics and the GD32 series of GigaDevice Semiconductor Inc., etc., can all support it.
[0020] The circuit schematic diagram of the present utility model is as Figure 1 shown:
[0021] 1. The MCU is the control unit, P is the PACK terminal, and B is the battery terminal; VB is the voltage of the battery terminal B, and VP is the voltage of the PACK terminal P.
[0022] 2. The voltage comparator U compares the voltage VB of the battery terminal B with the voltage VP of the PACK terminal P, and outputs a voltage control signal. After being ANDed with the charging control signal output by the MCU, it controls the second switch K2 in the charging circuit. After being inverted, this voltage control signal is ANDed with the discharge control signal output by the MCU to control the first switch K1 in the discharge circuit.
[0023] 3. During charging, when the voltage VP of the PACK terminal P is greater than the voltage VB of the battery terminal B, the discharge circuit is always in an open state, and whether charging is allowed can be controlled by the charging control signal output by the MCU.
[0024] 4. During discharge, when the voltage VP at the PACK terminal P is less than the voltage VB at the battery terminal B, the charging circuit is always in an open state, and whether to allow discharge can be controlled by the discharge control signal output by the MCU.
[0025] The present utility model realizes the control of the charge and discharge circuits by comparing the voltage differences on the circuit through a voltage comparator. When charging, the external voltage is greater than the internal voltage, and when discharging, the internal voltage is lower than the external voltage, thereby realizing the one-way conduction control of the charge and discharge circuits.
Claims
1. A control circuit for a lithium battery charging and discharging circuit, including a PACK terminal, a battery terminal, and an MCU, characterized in that: The voltage input signal (VP) at the PACK terminal (P) and the voltage input signal (VB) at the battery terminal (B) are respectively connected to the input terminals of a voltage comparator (U). The output terminal of the voltage comparator (U) is respectively connected to the input terminal of an inverter (N) and the input terminal A of a first AND gate (Y2). The output terminal of the inverter (N) is connected to the input terminal A of a second AND gate (Y1). The input terminal B of the second AND gate (Y1) is connected to the discharge control signal terminal of the MCU. The output terminal of the second AND gate (Y1) is connected to one end of a first switch (K1). The other end of the first switch (K1) is respectively connected to one end of a second switch (K2) and the discharge circuit of the battery terminal (B). The other end of the second switch (K2) is respectively connected to the output terminal of the first AND gate (Y2) and the charging circuit of the battery terminal (B). The input terminal B of the first AND gate (Y2) is connected to the charging control signal terminal of the MCU.
2. The control circuit for the charge and discharge loop of a lithium battery according to claim 1, wherein: The PACK terminal (P) is connected between the other end of the first switch (K1) and one end of the second switch (K2).
3. The control circuit for the charging and discharging circuit of a lithium battery according to claim 1, wherein: The MCU is an embedded chip, and the model of the MCU is one of the STM32 series of STMicroelectronics and the GD32 series of GigaDevice Semiconductor Inc.
4. The control circuit for a lithium battery charge and discharge loop according to claim 1 or 2, characterized in that: The discharge control signal terminal and the charging control signal terminal of the MCU are output by GPIO ports.
5. The control circuit for a lithium battery charge and discharge circuit according to claim 1, wherein: The first switch (K1) and the second switch (K2) are MOS field effect transistors or contactors.