Thermal runaway extremely early warning system based on expansive force-strain signal

Abstract

The invention relates to a thermal runaway extremely early warning system based on expansive force-strain signals. The thermal runaway extremely early warning system comprises a data acquisition unit, a data monitoring unit and an early warning unit, the data acquisition unit is used for acquiring real-time data of the battery; wherein the real-time data comprises a battery module expansion force signal and a battery cell strain signal; the data monitoring unit is used for monitoring and analyzing the expansion force signal of the battery module and the strain signal of the side surface of the battery, acquiring a thermal runaway fire risk level corresponding to the signals, and positioning a fault; and the early warning unit is used for carrying out early warning in different responses on different levels of thermal runaway fire risk levels. According to the thermal runaway extremely early warning system based on the expansive force-strain signal, the thermal runaway risk can be researched and judged according to the expansive force signal, the fault cell can be positioned according to the expansive force-strain signal corresponding relation, and thermal runaway extremely early warning can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal runaway warning for lithium-ion batteries, and in particular to an extremely early warning system for thermal runaway based on expansion force-strain signals. Background Art

[0002] The new energy sector has seen a booming development, with lithium-ion batteries playing a core role in energy storage power stations, electric vehicles and many other fields due to their excellent energy storage performance. However, when lithium-ion batteries are faced with extreme conditions such as thermal abuse, mechanical abuse and electrical abuse, thermal runaway may occur, leading to safety accidents such as fires or even explosions.

[0003] At present, the fire warning system of electrochemical energy storage stations mainly relies on temperature detection and characteristic gas detection technology. However, temperature detection requires the installation of sensors for each battery cell, which not only increases the cost of modification, but also the time difference for the internal temperature of the battery to be transmitted to the surface also leads to the lag of the warning. Although characteristic gas detection can detect the gas released after the battery safety valve is opened, it also has the problem of warning lag and inability to accurately locate abnormal batteries. In addition, other warning technologies such as implantable sensor warning and acoustic signal warning are also difficult to be widely used due to their high cost or limitations such as warning lag and difficult positioning. Most of the above warning signals cannot reflect the internal conditions of the battery in a timely and accurate manner, and their reliability for different thermal runaway processes needs to be considered.

[0004] Therefore, there is an urgent need to solve two core problems: one is to find a reliable source of early warning signals to improve the reliability of early warnings; the other is how to accurately identify and locate abnormal battery cells while issuing early warnings. Summary of the invention

[0005] The purpose of the present invention is to propose an extremely early warning system for thermal runaway based on expansion force-strain signals to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A thermal runaway early warning system based on expansion force-strain signals, comprising: a data acquisition unit, a data monitoring unit and an early warning unit;

[0008] The data acquisition unit is used to collect real-time data of the battery; wherein the real-time data includes: battery module expansion force signal and battery cell strain signal;

[0009] The data monitoring unit is used to monitor and analyze the battery module expansion force signal and the battery side strain signal, obtain the thermal runaway fire risk level corresponding to the signal, and locate the fault;

[0010] The early warning unit is used to provide early warnings with different responses for different levels of thermal runaway fire risk levels.

[0011] Optionally, the data acquisition unit includes: a force sensor and a strain sensor;

[0012] The force sensor is used to collect the expansion force signal of the battery module in real time;

[0013] The strain sensor is arranged on the side of the battery cell and is used to collect the strain signal of the battery cell in real time.

[0014] Optionally, the force sensor is arranged at a central position of a side surface of the battery module.

[0015] Optionally, the strain sensor is arranged at the center of the side surface of the battery cell and coincides with the center point of the side surface; wherein one strain sensor is arranged for a plurality of battery cells.

[0016] Optionally, the thermal runaway fire risk level corresponding to the signal acquired by the data monitoring unit includes:

[0017] Conduct thermal runaway experiments on batteries and obtain expansion force signals of battery modules in the experiments;

[0018] Based on the battery module expansion force signal in the experiment, the risk of thermal runaway fire is divided into several levels;

[0019] The battery module expansion force signal collected in real time is compared and analyzed with the battery module expansion force signal in the experiment after risk level classification to obtain the thermal runaway fire risk level corresponding to the real-time signal.

[0020] Optionally, the data monitoring unit performing fault location includes:

[0021] When the monitored battery module expansion force signal and the strain signal of the battery cell are in the same interval corresponding to the same thermal runaway fire risk level, the battery cell corresponding to the strain sensor that collects the abnormal signal is the faulty battery cell;

[0022] When the monitored battery module expansion force signal and the battery cell strain signal are not within the interval corresponding to the same thermal runaway fire risk level, the location of the faulty battery cell is determined according to different intervals of the thermal runaway fire risk level corresponding to the strain signal.

[0023] Optionally, the warning unit includes: a warning signal light and a controller;

[0024] The warning signal light is connected to a controller, and when the data acquisition unit reaches the warning threshold, the controller controls the warning signal light to operate.

[0025] The beneficial effects of the present invention are:

[0026] The present invention proposes a thermal runaway early warning system based on expansion force-strain signals, which uses a data acquisition unit to collect real-time data of the battery; uses a data monitoring unit to monitor and analyze the battery module expansion force signal and the battery side strain signal, obtains the thermal runaway fire risk level corresponding to the signal, and locates the fault; uses an early warning unit to give different response early warnings for different levels of thermal runaway fire risk levels. The thermal runaway early warning system based on expansion force-strain signals provided by the present invention can judge the thermal runaway risk based on the expansion force signal, and locate the faulty battery cell based on the corresponding relationship between the expansion force-strain signal, so as to achieve a very early warning of thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 It is a structural schematic diagram of a thermal runaway very early warning system based on expansion force-strain signals according to an embodiment of the present invention;

[0029] Figure 2 is a curve of expansion force and strain change rate of an embodiment of the present invention;

[0030] Figure 3 A thermal runaway expansion force and strain curve diagram of a battery cell in a thermal runaway very early warning system based on an expansion force-strain signal according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of locating a faulty battery cell in a thermal runaway early warning system based on expansion force-strain signals according to an embodiment of the present invention;

[0032] Among them, 1-host computer, 2-battery module housing, 3-battery module, 4-force sensor, 5-strain gauge, 6-data acquisition module, 7-warning signal light, 8-controller. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] This embodiment proposes a thermal runaway very early warning system based on expansion force-strain signals, including: a data acquisition unit, a data monitoring unit and a warning unit;

[0036] A data acquisition unit is used to collect real-time data of the battery; the real-time data includes: battery module expansion force signal and battery cell strain signal;

[0037] A data monitoring unit is used to monitor and analyze the battery module expansion force signal and the battery side strain signal, obtain the thermal runaway fire risk level corresponding to the signal, and locate the fault;

[0038] The early warning unit is used to provide early warnings with different responses for different levels of thermal runaway fire risk.

[0039] Furthermore, the data acquisition unit includes: a force sensor 3 and a strain sensor; wherein the strain sensor adopts a strain gauge 5 .

[0040] Force sensor 3, used for collecting battery module expansion force signals in real time;

[0041] The strain sensor is arranged on the side of the battery cell to collect the strain signal of the battery cell in real time.

[0042] Furthermore, the force sensor 3 is arranged at the center of the side surface of the battery module.

[0043] Furthermore, the strain sensor is arranged at the center of the side surface of the battery cell and coincides with the center point of the side surface; wherein one strain sensor is arranged for a plurality of battery cells.

[0044] Specifically, in this embodiment, Figure 1 As shown, the system mainly consists of a host computer 1, a force sensor 3, a strain sensor, a data acquisition module 6, a warning signal light 7 and a controller 8. The force sensor 3 and the strain sensor transmit the detected current and voltage signals to the data acquisition module 6 in real time, and the data acquisition module 6 performs preliminary data processing and then transmits the data to the host computer 1. The controller 8 is connected to the warning signal light 7 and the host computer 1. The host computer 1 displays the safety status of the battery module in real time and has a secondary warning function before the safety valve is opened.

[0045] The battery module in this embodiment is arranged in a battery module housing 2 and is composed of a plurality of battery cells.

[0046] The force sensor 3 of the present invention is arranged on the side of the battery module, monitors the overall expansion force of the module in real time, and is connected to the data acquisition module 6. The degree of thermal runaway fire risk can be determined based on the expansion force of the module.

[0047] The strain sensor of this embodiment can be a strain gauge 5 or an optical fiber sensor, etc. In this embodiment, the strain gauge 5 is taken as an example. The strain gauge 5 is arranged horizontally at the center of the side of the battery cell. One strain gauge 5 is arranged for every three battery cells. The strain size of the corresponding battery cell is monitored in real time, and the signal is transmitted to the data acquisition module 6 for preliminary processing before being transmitted to the host computer 1. More specifically, the strain gauge 5 is arranged horizontally at the center of the side of the battery cell, where the strain gauge 5 and the center point of the side coincide; the force sensor 3 is arranged on one side of the module, which is also the center position; the controller 8 and the data acquisition module 6 can be arranged in the module shell without any position requirements, and the warning signal light 7 is arranged outside the module.

[0048] The warning signal light 7 of this embodiment is connected to the controller 8. When the signal collected by the data acquisition module 6 reaches the warning threshold, the controller 8 controls the warning signal light 7 to operate.

[0049] Furthermore, the thermal runaway fire risk level corresponding to the signal obtained by the data monitoring unit includes:

[0050] Conduct thermal runaway experiments on batteries and obtain expansion force signals of battery modules in the experiments;

[0051] Based on the battery module expansion force signal in the experiment, the risk of thermal runaway fire is divided into several levels;

[0052] The battery module expansion force signal collected in real time is compared and analyzed with the battery module expansion force signal in the experiment after risk level classification to obtain the thermal runaway fire risk level corresponding to the real-time signal.

[0053] Furthermore, the data monitoring unit performs fault location including:

[0054] When the monitored battery module expansion force signal and the strain signal of the battery cell are in the same interval corresponding to the same thermal runaway fire risk level, the battery cell corresponding to the strain sensor that collects the abnormal signal is the faulty battery cell;

[0055] When the monitored battery module expansion force signal and the battery cell strain signal are not within the interval corresponding to the same thermal runaway fire risk level, the location of the faulty battery cell is determined according to different intervals of the thermal runaway fire risk level corresponding to the strain signal.

[0056] Further, the warning unit includes: a warning signal light 7 and a controller 8;

[0057] The warning signal light 7 is connected to the controller 8. When the data acquisition unit reaches the warning threshold, the controller 8 controls the warning signal light 7 to operate.

[0058] The system has a very early warning function for thermal runaway based on expansion force-strain signals. Figure 2 The figure shows the thermal runaway expansion force-strain curve of a battery cell. The superscript represents the expansion force interval and the subscript represents the strain interval. 0 is the normal operating range. Since the expansion force reflects the overall status of the module, the system divides the risk of thermal runaway fire into three levels based on the expansion force signal. 1 The first level warning will be triggered if it continues to rise to L 2 , a second-level warning will be triggered. In different warning intervals, the controller 8 will receive a signal to control the warning light 7 to operate. As the warning level increases, the flashing frequency of the warning light 7 increases.

[0059] In addition, the system can locate the faulty cell based on the corresponding relationship between the expansion force and the strain signal, such as Figure 4 There are two cases for fault location. If the expansion force and strain signal monitoring data are in the same corresponding interval, for example, the expansion force signal is in L 1 If the corresponding strain signal is within the L1 interval, the cell corresponding to the strain gauge 5 that collected the abnormal signal is the faulty cell; in the second case, if the expansion force and strain signal monitoring data are not within the same corresponding interval, as shown in the attached Figure 3 As shown, if the expansion force signal is at L 2 If the signal of strain gauge 51 is in the L0 range and the signal of strain gauge 52 is in the L1 range, the faulty cell is the cell between strain gauge 51 and strain gauge 52 and close to strain gauge 52. When the warning is triggered, the host computer 1 will display the thermal runaway fire risk warning level and the location of the faulty cell. Based on this, the extremely early warning of the thermal runaway fire risk and the precise location of the faulty cell can be achieved.

[0060] The present embodiment discloses an extremely early warning system for thermal runaway based on an expansion force-strain signal, comprising a battery module, a module housing, a strain sensor, a force sensor, a data collector, a controller, an early warning signal light and a host computer. The force sensor is arranged on the side of the battery module to monitor and collect the expansion force signal of the module in real time. The strain sensor is arranged at the center of the surface in the thickness direction of the battery cell, and a strain sensor is arranged for every three battery cells to monitor and collect the strain signal on the side of the battery in real time. The strain sensor and the force sensor are connected to the data acquisition module, which is connected to the controller, the host computer and the early warning signal light, and transmits the data to the host computer in real time. The extremely early warning system for thermal runaway based on the expansion force-strain signal provided by the present invention can judge the risk of thermal runaway based on the expansion force signal, and locate the faulty battery cell based on the corresponding relationship between the expansion force-strain signal, so as to achieve extremely early warning of thermal runaway.

[0061] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A thermal runaway early warning system based on expansion force-strain signal, characterized in that: include: Data collection unit, data monitoring unit and early warning unit; The data acquisition unit is used to collect real-time data of the battery; The real-time data includes: battery module expansion force signal and battery cell strain signal; The data monitoring unit is used to monitor and analyze the battery module expansion force signal and the battery side strain signal, obtain the thermal runaway fire risk level corresponding to the signal, and locate the fault; The early warning unit is used to provide early warnings with different responses for different levels of thermal runaway fire risk levels.

2. The thermal runaway early warning system based on expansion force-strain signal according to claim 1, characterized in that: The data acquisition unit includes: a force sensor and a strain sensor; The force sensor is used to collect the expansion force signal of the battery module in real time; The strain sensor is arranged on the side of the battery cell and is used to collect the strain signal of the battery cell in real time.

3. The thermal runaway early warning system based on expansion force-strain signal according to claim 2 is characterized in that: The force sensor is arranged at the center of the side surface of the battery module.

4. The thermal runaway early warning system based on expansion force-strain signal according to claim 2, characterized in that: The strain sensor is arranged at the center of the side surface of the battery cell and coincides with the center point of the side surface; wherein, one strain sensor is arranged for a plurality of battery cells.

5. The thermal runaway early warning system based on expansion force-strain signal according to claim 1, characterized in that: The thermal runaway fire risk level corresponding to the signal obtained by the data monitoring unit includes: Conduct thermal runaway experiments on batteries and obtain expansion force signals of battery modules in the experiments; Based on the battery module expansion force signal in the experiment, the risk of thermal runaway fire is divided into several levels; The battery module expansion force signal collected in real time is compared and analyzed with the battery module expansion force signal in the experiment after risk level classification to obtain the thermal runaway fire risk level corresponding to the real-time signal.

6. The thermal runaway early warning system based on expansion force-strain signal according to claim 2, characterized in that: The data monitoring unit performs fault location including: When the monitored battery module expansion force signal and the strain signal of the battery cell are in the same interval corresponding to the same thermal runaway fire risk level, the battery cell corresponding to the strain sensor that collects the abnormal signal is the faulty battery cell; When the monitored battery module expansion force signal and the battery cell strain signal are not within the interval corresponding to the same thermal runaway fire risk level, the location of the faulty battery cell is determined according to different intervals of the thermal runaway fire risk level corresponding to the strain signal.

7. The thermal runaway early warning system based on expansion force-strain signal according to claim 1, characterized in that: The early warning unit includes: an early warning signal light and a controller; The warning signal light is connected to a controller, and when the data acquisition unit reaches the warning threshold, the controller controls the warning signal light to operate.

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