Lithium battery protection circuit and method based on multi-parameter cooperative control

Abstract

The invention discloses a lithium battery protection circuit and method based on multi-parameter cooperative control. The lithium battery protection circuit comprises a main control module, a voltage sampling module, a temperature monitoring module, a battery temperature monitoring module, a current detection module, an equalization module, a communication module and a thermal management module, and the main control module performs weight analysis on the voltage, the temperature, the current, the internal resistance and the environment humidity through a fuzzy logic algorithm, dynamically adjusts a protection threshold value and triggers a protection action. A multi-parameter collaborative protection mechanism is adopted, and a dynamic protection threshold model is established by collecting the voltage, temperature, current, internal resistance and environment humidity of a single battery pack in real time. And carrying out weight analysis on multiple parameters by adopting a fuzzy logic algorithm, and triggering a protection action. According to the invention, an adaptive active equalization technology is adopted, and an equalization strategy is dynamically adjusted by combining SOC and SOH. The high-SOC battery is preferentially balanced at the last stage of charging, and the low-SOC battery is preferentially balanced at the last stage of discharging, so that the balancing efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery protection, and in particular to a lithium battery protection circuit and method based on multi-parameter coordinated control. Background Art

[0002] Lithium batteries are widely used in electric vehicles, energy storage systems, consumer electronics and other fields due to their high energy density, long cycle life and low self-discharge rate. However, lithium batteries are prone to thermal runaway under abnormal conditions such as overcharge, overdischarge, high temperature and short circuit, leading to combustion or explosion.

[0003] Traditional lithium battery protection circuits have the following defects: 1. Limitations of single parameter protection: Relying only on voltage or temperature as a single parameter to trigger protection, it is easy to cause misjudgment or missed judgment due to parameter fluctuations.

[0004] 2. Low balancing efficiency: Passive balancing consumes high energy, and active balancing circuits are complex and costly.

[0005] 3. Lack of fault prediction: Lack of real-time monitoring and early warning of battery internal resistance and capacity attenuation.

[0006] 4. Poor communication compatibility: The data interaction protocol with the entire vehicle or energy storage system is not unified. Summary of the invention

[0007] The purpose of the present invention is to solve the above problems and provide a high-precision lithium battery protection circuit and method based on multi-parameter coordinated control.

[0008] The technical solution of the present invention is: A lithium battery protection circuit based on multi-parameter coordinated control includes a main control module and a voltage sampling module, a temperature monitoring module, a battery temperature monitoring module, a current detection module, a balancing module, a communication module, and a thermal management module connected thereto; wherein: Voltage sampling module, real-time collection of voltage data of each lithium battery cell; Temperature monitoring module, monitoring lithium battery temperature; Current detection module, real-time collection of lithium battery charging and discharging current data; The main control module executes the multi-parameter coordinated protection algorithm and fault diagnosis; The balancing module dynamically adjusts the energy transfer strategy; Communication module, used to interact with external system data; Thermal management module, linked to the battery cooling system; The main control module performs weight analysis on voltage, temperature, current, internal resistance and ambient humidity through fuzzy logic algorithm, dynamically adjusts the protection threshold, and triggers the protection action.

[0009] Preferably, the balancing module includes a bidirectional DC-DC circuit based on SIC MOSFET, supports a maximum balancing current of 5A, prioritizes balancing high SOC batteries at the end of charging, and prioritizes balancing low SOC batteries at the end of discharging.

[0010] Preferably, the thermal management module dynamically adjusts the charge and discharge current according to the temperature distribution, and starts the liquid cooling or air cooling system when the temperature exceeds a set threshold.

[0011] Preferably, the main control module adopts a dual-core MCU architecture, the main core runs a multi-parameter collaborative protection algorithm, and the sub-core performs fault diagnosis and redundant communication switching.

[0012] Preferably, the communication module supports redundant communication channels and switches to a backup module when the main control unit fails.

[0013] A lithium battery protection method based on multi-parameter coordinated control includes the following steps: Real-time collection of battery cell voltage, temperature, current, internal resistance and ambient humidity parameters; Fuzzy logic algorithm is used to integrate and analyze multiple parameters and dynamically generate protection thresholds; Triggering protection actions based on analysis results, including cutting off the charge and discharge circuits, and starting the equalization or cooling system; Active balancing based on bidirectional DC-DC converter, adjusting energy transfer strategy according to SOC difference and battery health status; The long short-term memory network (LSTM) is used to predict the battery internal resistance growth trend and short circuit risk, and generate fault warnings.

[0014] Preferably, the active balancing strategy includes: in the charging stage, when the SOC difference exceeds 5%, the energy of the high SOC battery is preferentially transferred; in the static stage, when the internal resistance difference exceeds 10%, maintenance balancing is triggered.

[0015] Preferably, the specific triggering condition of the protection action is: When the single cell voltage exceeds 4.25V and lasts for 10 seconds, the charging circuit is cut off; When the cell voltage is lower than 2.8V and the SOC is lower than 5%, the discharge circuit is cut off; When the temperature exceeds 60°C, the charge and discharge current is reduced, and when it exceeds 70°C, the circuit is cut off.

[0016] Preferably, the method further comprises a periodic self-checking step: detecting the internal resistance of the battery daily, analyzing the capacity decay rate weekly and generating a state of health (SOH) report.

[0017] Preferably, the thermal management strategy includes: predicting the risk of local overheating through a temperature gradient sensor, and dynamically adjusting the heat dissipation intensity through a linkage cooling system.

[0018] The advantages of the present invention are: 1. The present invention adopts a multi-parameter coordinated protection mechanism, and establishes a dynamic protection threshold model by real-time acquisition of battery cell voltage, temperature, current, internal resistance and ambient humidity. Fuzzy logic algorithm is used to perform weight analysis on multiple parameters to trigger protection actions, such as cutting off the charge and discharge circuit and starting the cooling system.

[0019] 2. The present invention adopts adaptive active balancing technology, realizes energy transfer active balancing based on bidirectional DC-DC converter, and dynamically adjusts the balancing strategy by combining SOC (state of charge) and SOH (state of health). At the end of charging, high SOC batteries are prioritized for balancing, and at the end of discharging, low SOC batteries are prioritized for balancing, thereby improving balancing efficiency.

[0020] 3. The present invention adopts thermal-electric coupling management, integrates temperature gradient sensor and electrochemical impedance spectroscopy (EIS) detection module to predict local overheating risk, dynamically adjusts charging and discharging current according to temperature distribution, and links liquid cooling / air cooling system.

[0021] 4. The present invention adopts fault prediction and fault-tolerant control, analyzes historical data through long short-term memory network (LSTM), predicts the growth trend of battery internal resistance and potential short circuit risk. It supports redundant communication channels (CAN FD + Ethernet) and switches to the backup module when the main control unit fails.

[0022] Combining the above technologies, the present invention reduces the false protection rate to less than 1%, increases the equalization efficiency to 90%, extends the battery life by more than 20%, and advances the thermal runaway warning time by 5 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the lithium battery protection circuit of the present invention; Figure 2 It is a logic flow chart of multi-parameter coordinated protection; Figure 3 This is the topology diagram of the active balancing circuit; Figure 4 Schematic diagram of thermal management linkage control. DETAILED DESCRIPTION

[0024] like Figure 1 As shown, the present invention proposes a lithium battery protection circuit based on multi-parameter coordinated control, including a main control module and a voltage sampling module, a temperature monitoring module, a battery temperature monitoring module, a current detection module, a balancing module, a communication module, and a thermal management module connected thereto; wherein: A main control module, which is used to execute a multi-parameter coordinated protection algorithm and fault diagnosis. The main control module performs a weight analysis on the single cell voltage, temperature, current, internal resistance and ambient humidity parameters of the battery pack through a fuzzy logic algorithm, dynamically generates a protection threshold and triggers a protection action; The voltage sampling module is connected to the main control module and is used to collect voltage data of each cell of the battery pack in real time with a sampling accuracy of ±1mV. This embodiment uses the TI BQ76952 chip.

[0025] The temperature monitoring module is connected to the main control module and is used to detect the temperature data of each cell of the battery pack with a detection accuracy of ±0.5°C. This embodiment uses a PT1000 sensor.

[0026] A balancing module, which implements active balancing by energy transfer based on a bidirectional DC-DC converter. The balancing module dynamically adjusts the balancing strategy according to the state of charge (SOC) and state of health (SOH) of the battery pack; Communication module, supporting CAN FD, RS485 and wireless Bluetooth 5.0 protocols, for data interaction with external systems; Thermal management module, which integrates temperature gradient sensor and electrochemical impedance spectroscopy (EIS) detection module, is used to predict local overheating risk and dynamically adjust the charge and discharge current according to the temperature distribution, linking the liquid cooling or air cooling system; The fault prediction module analyzes historical data through the long short-term memory network (LSTM), predicts the growth trend of battery internal resistance and potential short-circuit risk, and generates a health status (SOH) report.

[0027] The main control module performs weight analysis on voltage, temperature, current, internal resistance and ambient humidity through fuzzy logic algorithm, dynamically adjusts the protection threshold, and triggers the protection action. This embodiment adopts a dual-core MCU (such as Infineon TC397), the main core runs the protection algorithm, and the secondary core is responsible for fault diagnosis.

[0028] The balancing module includes a bidirectional DC-DC circuit based on SIC MOSFET, supports a maximum 5A balancing current, prioritizes balancing high SOC batteries at the end of charging, and prioritizes balancing low SOC batteries at the end of discharging.

[0029] The thermal management module dynamically adjusts the charge and discharge current according to the temperature distribution, and starts the liquid cooling or air cooling system when the temperature exceeds a set threshold.

[0030] The main control module adopts a dual-core MCU architecture, the main core runs a multi-parameter collaborative protection algorithm, and the secondary core performs fault diagnosis and redundant communication switching.

[0031] The communication module supports redundant communication channels and switches to a backup module when the main control unit fails.

[0032] like Figure 2 As shown, the present invention also proposes a lithium battery protection method based on multi-parameter coordinated control, comprising the following steps: Real-time collection of battery cell voltage, temperature, current, internal resistance and ambient humidity parameters; Fuzzy logic algorithm is used to integrate and analyze multiple parameters and dynamically generate protection thresholds; Triggering protection actions based on analysis results, including cutting off the charge and discharge circuits, and starting the equalization or cooling system; Active balancing based on bidirectional DC-DC converter, adjusting energy transfer strategy according to SOC difference and battery health status; The long short-term memory network (LSTM) is used to predict the battery internal resistance growth trend and short circuit risk, and generate fault warnings.

[0033] like Figure 3 As shown, the active balancing strategy includes: in the charging stage, when the SOC difference exceeds 5%, the high SOC battery energy is transferred preferentially; in the static stage, when the internal resistance difference exceeds 10%, maintenance balancing is triggered.

[0034] The specific triggering conditions of the protection action are: When the single cell voltage exceeds 4.25V and lasts for 10 seconds, the charging circuit is cut off; When the cell voltage is lower than 2.8V and the SOC is lower than 5%, the discharge circuit is cut off; When the temperature exceeds 60°C, the charge and discharge current is reduced, and when it exceeds 70°C, the circuit is cut off.

[0035] The method also includes a periodic self-checking step: daily testing of the battery internal resistance, weekly analysis of the capacity decay rate and generation of a state of health (SOH) report.

[0036] like Figure 4 As shown, the thermal management strategy includes: predicting the risk of local overheating through a temperature gradient sensor, and dynamically adjusting the heat dissipation intensity through a linked cooling system.

[0037] The present invention adopts a multi-parameter coordinated protection mechanism, establishes a dynamic protection threshold model by real-time acquisition of battery cell voltage, temperature, current, internal resistance and ambient humidity, and uses a fuzzy logic algorithm to perform weight analysis on multiple parameters to trigger protection actions, such as cutting off the charge and discharge circuit and starting the cooling system.

[0038] The present invention adopts adaptive active balancing technology, realizes energy transfer active balancing based on bidirectional DC-DC converter, and dynamically adjusts the balancing strategy by combining SOC (state of charge) and SOH (state of health). At the end of charging, high SOC batteries are prioritized for balancing, and at the end of discharging, low SOC batteries are prioritized for balancing, thereby improving balancing efficiency.

[0039] The present invention adopts thermal-electric coupling management, integrates temperature gradient sensor and electrochemical impedance spectroscopy (EIS) detection module to predict local overheating risk, dynamically adjusts charging and discharging current according to temperature distribution, and links liquid cooling / air cooling system.

[0040] The present invention adopts fault prediction and fault-tolerant control, analyzes historical data through long short-term memory network (LSTM), predicts the growth trend of battery internal resistance and potential short-circuit risk. It supports redundant communication channels (CAN FD + Ethernet) and switches to the backup module when the main control unit fails.

[0041] Combining the above technologies, the present invention reduces the false protection rate to less than 1%, increases the equalization efficiency to 90%, extends the battery life by more than 20%, and advances the thermal runaway warning time by 5 minutes.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any modifications made according to the spirit of the main technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A lithium battery protection circuit based on multi-parameter coordinated control, characterized in that: It includes the main control module and its connected voltage sampling module, temperature monitoring module, battery temperature monitoring module, current detection module, balancing module, communication module, and thermal management module; among which: Voltage sampling module, real-time collection of voltage data of each lithium battery cell; Temperature monitoring module, monitoring lithium battery temperature; Current detection module, real-time collection of lithium battery charging and discharging current data; The main control module executes the multi-parameter coordinated protection algorithm and fault diagnosis; The balancing module dynamically adjusts the energy transfer strategy; Communication module, used to interact with external system data; Thermal management module, linked to the battery cooling system; The main control module performs weight analysis on voltage, temperature, current, internal resistance and ambient humidity through fuzzy logic algorithm, dynamically adjusts the protection threshold, and triggers the protection action.

2. The lithium battery protection circuit according to claim 1, characterized in that: The balancing module includes a bidirectional DC-DC circuit based on SICMOSFET, supports a maximum 5A balancing current, prioritizes balancing high SOC batteries at the end of charging, and prioritizes balancing low SOC batteries at the end of discharging.

3. The lithium battery protection circuit according to claim 1, characterized in that: The thermal management module dynamically adjusts the charge and discharge current according to the temperature distribution, and starts the liquid cooling or air cooling system when the temperature exceeds a set threshold.

4. The lithium battery protection circuit according to claim 1, characterized in that: The main control module adopts a dual-core MCU architecture, the main core runs a multi-parameter collaborative protection algorithm, and the secondary core performs fault diagnosis and redundant communication switching.

5. The lithium battery protection circuit according to claim 1, characterized in that: The communication module supports redundant communication channels and switches to a backup module when the main control unit fails.

6. A lithium battery protection method based on multi-parameter coordinated control, characterized in that: The following steps are involved: Real-time collection of battery cell voltage, temperature, current, internal resistance and ambient humidity parameters; Fuzzy logic algorithm is used to integrate and analyze multiple parameters and dynamically generate protection thresholds; Triggering protection actions based on analysis results, including cutting off the charge and discharge circuits, and starting the equalization or cooling system; Active balancing based on bidirectional DC-DC converter, adjusting energy transfer strategy according to SOC difference and battery health status; The long short-term memory network (LSTM) is used to predict the battery internal resistance growth trend and short circuit risk, and generate fault warnings.

7. The method according to claim 6, characterized in that The active balancing strategy includes: in the charging stage, when the SOC difference exceeds 5%, the energy of the high SOC battery is transferred first; in the static stage, when the internal resistance difference exceeds 10%, maintenance balancing is triggered.

8. The method according to claim 6, characterized in that The specific triggering conditions of the protection action are: When the single cell voltage exceeds 4.25V and lasts for 10 seconds, the charging circuit is cut off; When the cell voltage is lower than 2.8V and the SOC is lower than 5%, the discharge circuit is cut off; When the temperature exceeds 60°C, the charge and discharge current is reduced, and when it exceeds 70°C, the circuit is cut off.

9. The method according to claim 6, characterized in that The method also includes a periodic self-checking step: daily testing of the battery internal resistance, weekly analysis of the capacity decay rate and generation of a state of health (SOH) report.

10. The method according to claim 6, characterized in that The thermal management strategy includes: predicting the risk of local overheating through a temperature gradient sensor, and linking the cooling system to dynamically adjust the heat dissipation intensity.

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