Lithium battery system thermal runaway emergency risk avoiding device and risk avoiding method

Abstract

The invention discloses a lithium battery system thermal runaway emergency risk avoiding device which comprises a detection module, a judgment module and an execution module. The detection module comprises a temperature sensor and a deformation sensor, and the temperature sensor and the deformation sensor are used for detecting surface temperature information and deformation information of each single battery in the battery module and sending the surface temperature information and the deformation information to the judgment module; the judgment module is used for calculating whether the control is out of control through a BP neural network model based on the surface temperature information and the deformation information, and controlling the execution module to act when the control is out of control; the execution module is arranged on each single battery and comprises a change-over switch and a conductive bypass, the change-over switches are arranged on the positive electrode and the negative electrode of the single battery, and when the execution module acts, the power supply circuit connected with the positive electrode and the negative electrode of the single battery is disconnected from the single battery and connected to the conductive bypass. The invention further discloses a risk avoiding method achieved through the risk avoiding device. According to the invention, the single batteries with out-of-control risks are eliminated without interrupting power before the thermal runaway of the power battery occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of battery measurement and control, and in particular to a thermal runaway emergency avoidance device and a method for avoiding thermal runaway of a lithium battery system. Background Art

[0002] Lithium batteries are widely used in electronic products, transportation power sources, power storage equipment, etc., especially new energy vehicles, due to their advantages of being green, environmentally friendly and having a long service life. The rise of new energy vehicles has brought many conveniences to people. However, during the use of such vehicles, safety accidents caused by thermal runaway of batteries frequently occur, which greatly endangers the lives of people on board.

[0003] When a lithium battery experiences thermal runaway in a single cell during use, it will quickly cause the temperature of other single cells in the same circuit to rise immediately, causing the entire battery to experience thermal runaway, or even combustion or explosion.

[0004] At present, the monitoring of thermal runaway of battery systems in new energy vehicles is mainly through the collection and analysis of information on gas, temperature, and volume changes, and then reminding the owner of the thermal runaway of the battery system. However, the above methods only serve as reminders and cannot control the single battery that causes thermal runaway without stopping the operation of the vehicle's power battery. Summary of the invention

[0005] In response to the above technical needs, the present invention provides a lithium battery system thermal runaway emergency avoidance device. The present invention also provides a method for preparing the lithium battery system thermal runaway emergency avoidance device to solve the problem of how to monitor the battery condition in real time before thermal runaway occurs in the power battery and eliminate the heat source without terminating the operation of the vehicle power battery.

[0006] The technical solution of the present invention is as follows: A thermal runaway emergency avoidance device for a lithium battery system, comprising a detection module, a discrimination module and an execution module;

[0007] The detection module includes a temperature sensor and a deformation sensor, and the temperature sensor and the deformation sensor are used to detect the surface temperature information and deformation information of each single battery in the battery module and send them to the discrimination module;

[0008] The discrimination module is used to calculate whether it is out of control through a BP neural network model based on the surface temperature information and deformation information, and control the execution module to act when out of control;

[0009] The execution module is arranged at each single cell, and comprises a switching switch and a conductive bypass. The switching switch is arranged at the positive and negative poles of the single cell. When the execution module is actuated, the power supply circuit connected to the positive and negative poles of the single cell is disconnected from the single cell and connected to the conductive bypass.

[0010] Furthermore, a display module is included, and the display module is used to display surface temperature information and deformation information.

[0011] Furthermore, it comprises an alarm module, which generates an alarm message when the determination module obtains a result of out-of-control through calculation, and the display module is used to display the alarm message.

[0012] Furthermore, the deformation sensor comprises a first boundary layer, a piezoelectric ceramic layer and a second boundary layer stacked in sequence to form a sheet structure, and the deformation sensor surrounds and covers the surface of the single battery.

[0013] Furthermore, the temperature sensor is a sheet-shaped thermocouple, and the temperature sensor is arranged outside the deformation sensor.

[0014] Furthermore, each single battery is arranged in a battery slot, the conductive bypass is arranged in a side wall of the battery slot, and the switching switch is installed at both ends of the battery slot.

[0015] Another technical solution of the present invention is as follows: A thermal runaway avoidance method for a lithium battery system emergency avoidance device, comprising the steps of: a temperature sensor and a deformation sensor detect the surface temperature information and deformation information of each single cell in real time and send them to a discrimination module, the discrimination module calculates whether it is out of control based on the surface temperature information and deformation information through a BP neural network model, and when the calculation result is out of control, the control execution module acts by the switching switch of the corresponding single cell to cut off the connection between the power supply circuit connected to the positive and negative poles of the single cell and the single cell and connect it to a conductive bypass.

[0016] Furthermore, the surface temperature information and deformation information detected in real time by the temperature sensor and the deformation sensor are sent to the display module for display, and the surface temperature information and deformation information both include the position information of the single battery.

[0017] Furthermore, when the determination module obtains a calculation result indicating that the system is out of control, the alarm module generates an alarm message and sends it to the display module, and the display module displays the alarm message.

[0018] Furthermore, the BP neural network has an input layer, a hidden layer and an output layer. The number of nodes in the input layer is 2, the number of nodes in the hidden layer is 2, and the number of nodes in the output layer is 2.

[0019] The advantages of the present invention compared with the prior art are:

[0020] A temperature sensor and a deformation sensor are set for each single cell, and the switch and the conductive bypass are used to decide whether the single cell is connected to the power supply circuit as the power supply source. The surface temperature and deformation information obtained by the temperature sensor and the deformation sensor are used to judge the single cell with the risk of runaway using the BP neural network, and exclude it from the power supply circuit, ensuring the effective control of thermal runaway and the normal operation of the vehicle battery, thereby improving the safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a module of a thermal runaway emergency avoidance device for a lithium battery system according to an embodiment.

[0022] Figure 2 This is a schematic diagram of the structure of the temperature sensor and deformation sensor installed on the single battery.

[0023] Figure 3 This is a schematic diagram of the structure of the execution module set on the single battery.

[0024] Figure 4 This is a schematic diagram of the structure in which a single battery cell with a risk of thermal runaway in a battery module is removed from the working circuit. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments, but are not intended to limit the present invention.

[0026] Please combine Figure 1 As shown, the lithium battery system thermal runaway emergency avoidance device involved in this embodiment includes a detection module 100, a determination module 200, an execution module 300, a display module 400 and an alarm module 500.

[0027] Please combine Figure 2As shown, the detection module 100 mainly includes a temperature sensor and a deformation sensor, which are used to obtain the surface temperature information and deformation information of the single battery in real time, and send the surface temperature information and deformation information to the discrimination module 200 for processing. The deformation sensor 101 covers the circumferential surface of each single battery, and the two are in close contact. The size of the deformation sensor 101 matches the size of the battery, has a certain ductility and flexibility, and can be rolled into a cylindrical shape around the single battery to wrap the single battery. The structure of the deformation sensor 101 is a three-layer structure, the first boundary layer 101a and the second boundary layer 101c are low thermal resistance layers made of pure copper, and piezoelectric ceramics are used in the middle as the crystal layer 101b, and the signal line is led out from the middle crystal layer 101b. When the battery is deformed, the crystal layer 101b is squeezed, the spacing between the crystals changes, which causes the number of electrons therein to change. The deformation of the battery surface can be monitored through electronic signal conversion, and a deformation signal is generated. The structure of the temperature sensor 102 also adopts a three-layer structure, the upper and lower layers are boundary layers 102a, and the middle layer is a temperature sensing thermocouple 102b. Due to the temperature difference, the thermal resistance of the temperature sensing metal in the temperature sensor 102 changes. The temperature change of the battery surface can be monitored through electronic signal conversion and a surface temperature signal can be generated.

[0028] The single cell battery is divided into battery units according to a single cell or multiple cells, and then the single cell or multiple battery units are divided into battery modules, and multiple battery modules constitute the entire power battery. The surface temperature information and deformation information obtained by the temperature sensor 102 and the deformation sensor 101 are also divided according to the division logic of the single cell battery, so as to facilitate the identification of the specific single cell battery position that generates the risk of thermal runaway.

[0029] The discrimination module 200 is mainly used to receive surface temperature information and deformation information to determine whether there is a risk of thermal runaway of the battery. The discrimination module 200 can be integrated into the existing vehicle controller. The discrimination module 200 uses a BP neural network as a discrimination model for thermal runaway. The BP neural network consists of an input layer, a hidden layer, and an output layer. The number of nodes in the input layer, hidden layer, and output layer are 2, 2, and 2, respectively. The two nodes of the input layer are the battery surface temperature (K) and the battery deformation information (%). The two nodes of the output layer input 1 and 0 respectively. When there is a risk of thermal runaway of the battery, the output is 1; when there is no risk of thermal runaway, the output is 0. When the output is 1, that is, there is a risk of thermal runaway of the battery, the discrimination module 200 controls the execution module 300 to act based on the corresponding single cell position information. In addition, in this embodiment, an alarm module 500 is also configured. When the output of the judgment module 200 is 1, the alarm module 500 generates an alarm message to provide feedback to the driver, and at the same time sends the thermal runaway alarm message to the display module 400 to remind the driver that the car is at risk of electromagnetic thermal runaway.

[0030] Please combine Figure 3 and Figure 4 As shown, the execution module 300 is a battery card slot 301 with a conductive bypass 303, which is arranged on each single battery. The battery card slot 301 is a frame-type structure, and the outermost layer is a heat-insulating protective layer. While protecting the battery from external impact, it can also isolate the thermal impact of the battery heat generation on the surrounding batteries, and reduce the impact of external heat on the battery in the battery card slot 301. The inner layer is also a heat-insulating protective layer, which can separate the circuit accessories of the conductive bypass 303 from the working battery, and reduce the thermal impact of the battery heat generation on the conductive bypass 303. A switching switch 302 is installed at both ends of the positive and negative poles of the battery card slot 301. The switching switch 302 can be a micro relay. The moving contacts of the relay are respectively connected to the positive and negative poles of the battery and the two ends of the conductive bypass 303, and the static contacts of the relay are connected to the power supply circuit. By controlling the switching switch 302 by PLC, the power supply circuit where the battery is located can be disconnected, and the power supply circuit on the single battery connected in series can be connected to the conductive bypass 303, and the conductive bypass 303 can be disconnected to restore the power supply circuit where the working battery is located. The conductive bypass 303 is arranged between the inner and outer insulation protection layers. When the battery is in thermal runaway, the battery with the risk of thermal runaway is removed from the working circuit 600, and the thermal runaway battery no longer participates in the operation of the circuit. At the same time, the conductive bypass 303 is connected to control the battery with the risk of thermal runaway while ensuring the normal operation of the power battery. The conductive bypass 303 uses a low-resistance metal as a circuit conductor, and the outer layer of the conductor has an insulating protective layer. The positive and negative contacts of the conductive bypass 303 are installed at the positive and negative poles of the battery card slot 301; the space for installing the conductive bypass 303 has a certain space, which is convenient for the gas flow in the battery system and is conducive to heat dissipation.

[0031] The display module 400 is connected to the detection module 100 and the alarm module 500, receives surface temperature information, deformation information and alarm information, and displays the temperature and deformation status of each single battery by position through the position division logic of the surface temperature information and deformation information, so that the driver can understand the battery status at any time, and displays the alarm information when the alarm information is obtained to further remind the driver of the thermal runaway risk of the battery.

[0032] The risk avoidance method of the thermal runaway emergency avoidance device of the lithium battery system is that the temperature sensor 102 and the deformation sensor 101 detect the single battery in real time, and send the measured surface temperature information and deformation information to the judgment module 200 and the display module 400; the display unit displays all the received surface temperature information and deformation information according to the position according to the preset position division logic (that is, the battery module is displayed in the form of a diagram, and the surface temperature information and deformation information are displayed at the corresponding diagram position) to intuitively display the temperature and deformation of each single battery. At the same time, the judgment module 200 judges the risk of runaway for the received surface temperature information and deformation information according to each single battery according to the pre-trained BP neural network model. When the surface temperature information and deformation information of a single battery are judged to have a risk of thermal runaway by the judgment module 200, the alarm module 500 forms an alarm message to alarm, and sends the alarm information to the display module 400 at the same time, and the display module 400 displays the alarm information. Through the alarm information, it is possible to track which single battery surface temperature information and deformation information generate the risk of thermal runaway, and then the display module 400 can also display the alarm information at the corresponding position.

[0033] In addition, when the identification module 200 determines that a single cell battery has a risk of thermal runaway, it will control the execution module 300 corresponding to the single cell battery to operate, and the relay will perform a switching action to switch the connection between the working circuit 600 and the single cell battery to a connection with the conductive bypass 303. In this way, the battery with a risk of thermal runaway will be removed from the working circuit to prevent it from continuing to work and causing uncontrollable hazards.

Claims

1. A thermal runaway emergency avoidance device for a lithium battery system, characterized in that: It includes a detection module, a discrimination module and an execution module; The detection module includes a temperature sensor and a deformation sensor, and the temperature sensor and the deformation sensor are used to detect the surface temperature information and deformation information of each single battery in the battery module and send them to the discrimination module; The discrimination module is used to calculate whether it is out of control through a BP neural network model based on the surface temperature information and deformation information, and control the execution module to act when out of control; The execution module is arranged at each single cell, and comprises a switching switch and a conductive bypass. The switching switch is arranged at the positive and negative poles of the single cell. When the execution module is actuated, the power supply circuit connected to the positive and negative poles of the single cell is disconnected from the single cell and connected to the conductive bypass.

2. The thermal runaway emergency avoidance device for a lithium battery system according to claim 1, characterized in that: A display module is included, and the display module is used to display surface temperature information and deformation information.

3. The thermal runaway emergency avoidance device for a lithium battery system according to claim 2, characterized in that: It includes an alarm module, which generates alarm information when the determination module obtains a result of out-of-control through calculation, and the display module is used to display the alarm information.

4. The thermal runaway emergency avoidance device for a lithium battery system according to claim 1, characterized in that: The deformation sensor comprises a first boundary layer, a piezoelectric ceramic layer and a second boundary layer stacked in sequence to form a sheet structure, and the deformation sensor surrounds and covers the surface of the single battery.

5. The thermal runaway emergency avoidance device for a lithium battery system according to claim 4, characterized in that: The temperature sensor is a sheet-shaped thermocouple, and the temperature sensor is arranged outside the deformation sensor.

6. The thermal runaway emergency avoidance device for a lithium battery system according to claim 1, characterized in that: Each single battery is arranged in a battery slot, a side wall of the battery slot is provided with the conductive bypass, and both ends of the battery slot are provided with the switching switch.

7. A method for avoiding thermal runaway emergency avoidance of a lithium battery system according to any one of claims 1 to 6, characterized in that: include: The temperature sensor and deformation sensor detect the surface temperature information and deformation information of each single cell in real time and send them to the discrimination module. The discrimination module calculates whether it is out of control based on the surface temperature information and deformation information through the BP neural network model. When the calculation result is out of control, the control execution module acts by the switching switch of the corresponding single cell to cut off the connection between the power supply circuit connected to the positive and negative poles of the single cell and the single cell and connect it to the conductive bypass.

8. A method for avoiding thermal runaway emergency avoidance of a lithium battery system as claimed in claim 2 or 3, characterized in that: include: The temperature sensor and the deformation sensor detect the surface temperature information and deformation information of each single cell in real time and send them to the discrimination module. The discrimination module calculates whether it is out of control through the BP neural network model based on the surface temperature information and deformation information. When the calculation result is out of control, the control execution module acts by the switching switch of the corresponding single cell to cut off the connection between the power supply circuit connected to the positive and negative poles of the single cell and the single cell and connect it to the conductive bypass. The surface temperature information and deformation information detected in real time by the temperature sensor and the deformation sensor are sent to the display module for display, and the surface temperature information and deformation information both include the position information of the single cell.

9. The risk avoidance method of the thermal runaway emergency avoidance device for a lithium battery system according to claim 8, characterized in that: When the determination module obtains a calculation result indicating that the system is out of control, the alarm module generates an alarm message and sends it to the display module, and the display module displays the alarm message.

10. The risk avoidance method of the thermal runaway emergency avoidance device for a lithium battery system according to claim 7 or 8, characterized in that: The BP neural network has an input layer, a hidden layer and an output layer. The number of nodes in the input layer is 2, the number of nodes in the hidden layer is 2, and the number of nodes in the output layer is 2.

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