A lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing

Abstract

The utility model discloses a kind of lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable type temperature sensing, belong to lithium battery thermal runaway early warning device technical field, including module shell, the detachable installation of module cover plate is positioned at the top of module shell, its inside detachably fixedly connected with electric core support, multiple square shell electric core are connected with the detachable installation of jack in the electric core support, safety valve is installed in the exhaust port of square shell electric core, acoustic sensor is installed in the both sides of module shell;Adjacent two square shell electric core are clamped and installed with composite sensor.In the utility model, through temperature, pressure, deformation, gas and acoustic five-dimensional collaborative monitoring, in combination with the exclusive acoustic fingerprint of miniature sawtooth flow guide groove and time difference positioning technology, fault electric core can be accurately locked, and through multi-signal linkage judgment thermal runaway grade, solve the problem that traditional single-dimension monitoring is easy to misreport, miss report.

Description

Technical Field

[0001] This utility model belongs to the technical field of lithium battery thermal runaway early warning devices, and particularly relates to a lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing. Background Technology

[0002] Lithium-ion batteries, with their outstanding advantages such as high energy density, long cycle life, and no memory effect, have become the core energy carrier for new energy vehicles, energy storage systems, and portable electronic devices, profoundly driving the transformation of energy structure and the upgrading of electronic devices. However, under charge-discharge cycles, long-term storage, or abnormal operating conditions, lithium-ion batteries are prone to thermal runaway reactions due to problems such as cell overheating, internal short circuits, and overcharging / over-discharging. This can rapidly release toxic pyrolysis gases such as CO and HF, while simultaneously causing a sudden increase in internal pressure and temperature within the cell. In severe cases, this can lead to battery fires and explosions, posing a significant threat to personal safety, property safety, and the public environment. In existing technologies, a structure consisting of a lithium battery charging and discharging structure, a sealed chamber, temperature and pressure sensors, and an early warning unit is used. This structure monitors the temperature change rate and pressure of the inert gas inside the sealed chamber to provide early warning of thermal runaway. It also detects sensor malfunctions and leaks in the sealed chamber. However, this approach relies solely on two-dimensional temperature and pressure monitoring, which does not cover cell deformation, characteristic gases, and acoustic signals. Furthermore, it cannot accurately locate faulty cells, resulting in a single early warning dimension and insufficient positioning accuracy. Summary of the Invention

[0003] The purpose of this invention is to propose a lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing, in order to solve the problem that traditional technologies rely only on two-dimensional temperature and pressure monitoring and do not cover cell deformation, characteristic gases, and acoustic signals.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing includes a module housing, a module cover plate is detachably installed on the top of the module housing, a cell bracket is detachably fixed inside the cover plate, multiple square-shell cells are snapped into the cell bracket, a safety valve is installed at the exhaust port of the square-shell cells, and acoustic sensors are installed on both sides of the module housing. A composite sensor is clamped and installed between two adjacent square-shell cells. The composite sensor includes a pressure sensor, a deformation strain gauge, and a micro electrochemical gas sensing unit. The bottom of the module cover plate has a continuous channel that extends along the arrangement direction of the square-shell battery cells and is equipped with a temperature-sensing fiber optic sensor.

[0005] Preferably, mounting bases are installed on both sides of the module housing, and a protective shell is fixedly connected inside the mounting base. The acoustic sensor is installed inside the protective shell, and sound-absorbing cotton is filled between the protective shell and the acoustic sensor.

[0006] Preferably, the exhaust port edge of the square-shell battery cell is provided with a micro-serrated guide groove. The tooth pitch of the micro-serrated guide groove is not consistent on different square-shell battery cells. An exhaust guide edge is integrally formed on the outer side of the exhaust port of the square-shell battery cell to guide the gas flowing through the safety valve to the acoustic sensor.

[0007] Preferably, the composite sensor includes a substrate, the pressure sensor is mounted in the middle of the substrate, two strain gauges are mounted on opposite sides of the substrate, the side of the strain gauge away from the substrate is attached to the sidewall of the same side of the square-shell battery cell, the sensing end of the pressure sensor is connected to one strain gauge, and two micro electrochemical gas sensing units are mounted on opposite sides of the substrate, with a selectively permeable membrane fixedly connected to the side of the micro electrochemical gas sensing unit away from the substrate.

[0008] Preferably, the continuous channel covers multiple safety valve areas, and a heat-conducting layer, an embedding layer, and a heat dissipation layer are fixedly attached to the inside of the continuous channel from bottom to top, and the temperature-sensing fiber optic sensor is embedded inside the embedding layer.

[0009] Preferably, a control circuit is installed on the module housing, and the control circuit is electrically connected to the acoustic sensor, pressure sensor, deformation strain gauge, micro electrochemical gas sensing unit and temperature-sensing fiber optic sensor.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. In this utility model, by coordinating five-dimensional monitoring of temperature, pressure, deformation, gas and acoustics, combined with the exclusive acoustic fingerprint and time difference positioning technology of the micro-serrated guide groove, the faulty battery cell can be accurately located. At the same time, the thermal runaway level can be judged by multi-signal linkage, which solves the problem of false alarm and missed alarm in traditional single-dimensional monitoring.

[0011] 2. In this utility model, the exhaust guide edge is oriented to guide the gas along the vertical electrode connection line to avoid short circuits and corrosion caused by pyrolysis gas contacting the electrode; the selectively breathable membrane of the composite sensor and the protective shell and sound-absorbing cotton design of the acoustic sensor not only ensure the stability of the sensor, but also prevent the accumulation of thermal runaway gas and improve the operational safety of the module. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of a lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing proposed in this utility model. Figure 2This is a vertical sectional view of a lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing proposed in this utility model. Figure 3 for Figure 2 Enlarged diagram of part A in the middle; Figure 4 This is a schematic diagram of the cell support and square cell structure of a lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing proposed in this utility model. Figure 5 This is a cross-sectional view of the substrate portion of a lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing proposed in this utility model. Figure 6 This is a block diagram of a lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing proposed in this utility model.

[0013] In the diagram: 1. Module housing, 2. Module cover plate, 3. Cell bracket, 4. Square-shell cell, 5. Safety valve, 6. Protective shell, 7. Sound-absorbing cotton, 8. Acoustic sensor, 9. Miniature serrated guide groove, 10. Exhaust guide edge, 11. Substrate, 12. Pressure sensor, 13. Deformation strain gauge, 14. Miniature electrochemical gas sensing unit, 15. Selective breathable membrane, 16. Continuous channel, 17. Temperature-sensing fiber optic sensor, 18. Thermal conductive layer, 19. Embedding layer, 20. Heat dissipation layer, 21. Control circuit. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0015] Reference Figures 1-6 A lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable temperature sensing includes a module housing 1, a module cover plate 2 detachably installed on the top of the module housing 1, a cell bracket 3 detachably fixedly connected inside the cover plate 2, a plurality of square-shell cells 4 are snapped into the cell bracket 3, a safety valve 5 is installed at the exhaust port of the square-shell cells 4, and acoustic sensors 8 are installed on both sides of the module housing 1.

[0016] The module housing 1 is the core load-bearing structure of the device. It is made of flame-retardant engineering plastic in one piece to prevent external moisture and dust from entering.

[0017] The module cover plate 2 is detachably connected to the module housing 1 by bolts, which facilitates the later maintenance of the sensor and battery cell.

[0018] The cell bracket 3 adopts a hollow design, which not only ensures the stable connection of the square-shell cell 4, but also provides a heat dissipation channel.

[0019] Multiple square-shell battery cells 4 are arranged side by side along the length of the module to form a standardized battery cell module.

[0020] Safety valve 5 is a pressure relief structure built into the square-shell battery cell 4. It automatically opens to release gas when the internal pressure of the battery cell exceeds the standard. Acoustic sensor 8 is used to accurately capture the acoustic signal when the gas is released.

[0021] Mounting bases are installed on both sides of the module housing 1. A protective shell 6 is fixedly connected inside the mounting base. An acoustic sensor 8 is installed inside the protective shell 6. Sound-absorbing cotton 7 is filled between the protective shell 6 and the acoustic sensor 8.

[0022] The mounting base is a metal bracket welded to the inner wall of the module housing 1. Its position is aligned with the height of the safety valve 5 of the square-shell battery cell 4 to ensure that the acoustic sensor 8 can receive the directional acoustic signal.

[0023] The protective shell 6 is made of high-temperature resistant material, which provides physical protection for the acoustic sensor 8, preventing it from being corroded by pyrolysis gas or damaged by external impact.

[0024] The sound-absorbing cotton 7 is made of high-temperature resistant glass wool, which can filter the background noise inside the module, such as the noise of the battery cell cooling fan and slight vibration noise, and improve the signal recognition accuracy of the acoustic sensor 8.

[0025] The exhaust port edge of the square-shell battery cell 4 is provided with a micro-serrated guide groove 9. The tooth pitch of the micro-serrated guide groove 9 on different square-shell battery cells 4 is not consistent. An exhaust guide edge 10 is integrally formed on the outer side of the exhaust port of the square-shell battery cell 4, which is used to guide the gas flowing through the safety valve 5 to the acoustic sensor 8.

[0026] The miniature serrated guide groove 9 is integrally stamped into the top cover plate of the square battery cell 4. The tooth pitch is designed differently for adjacent battery cells, so that each square battery cell 4 forms a unique acoustic fingerprint when it discharges gas, which makes it easy for the acoustic sensor 8 to distinguish faulty battery cells.

[0027] The exhaust guide edge 10 is set in a direction perpendicular to the line connecting the two electrodes of the square battery cell 4. It can guide the pyrolysis gas discharged from the safety valve 5 laterally to the acoustic sensors 8 on both sides of the module housing 1, while preventing the pyrolysis gas from rushing towards the electrodes of the square battery cell 4 or adjacent square battery cells 4, thus eliminating the risk of short circuit and corrosion.

[0028] A composite sensor is clamped between two adjacent square-shell cells 4. The composite sensor includes a pressure sensor 12, a deformation strain gauge 13, and a miniature electrochemical gas sensing unit 14.

[0029] The overall thickness of the composite sensor is precisely matched with the gap between the adjacent square-shell battery cells 4. Stable clamping is achieved through the arrangement pressure of the adjacent square-shell battery cells 4 themselves. No additional fasteners are required, making installation convenient. It integrates three monitoring functions: pressure, deformation, and gas. It can simultaneously capture pressure changes, bulging deformation, and characteristic gas release in the early stage of thermal runaway of the square-shell battery cells 4, realizing multi-dimensional collaborative early warning.

[0030] The composite sensor includes a substrate 11, a pressure sensor 12 mounted in the middle of the substrate 11, two strain gauges 13 mounted on opposite sides of the substrate 11, the side of the strain gauge 13 away from the substrate 11 being attached to the side wall of the same side square-shell battery cell 4, the sensing end of the pressure sensor 12 being connected to one strain gauge 13, and two miniature electrochemical gas sensing units 14 mounted on opposite sides of the substrate 11, with a selectively permeable membrane 15 fixedly connected to the side of the miniature electrochemical gas sensing unit 14 away from the substrate 11.

[0031] The substrate 11 is made of flexible epoxy resin, which has a certain degree of elasticity and can adapt to the slight expansion and deformation of the square-shell cell 4 without damage.

[0032] The deformation strain gauge 13 is a metal foil strain gauge. After being attached to the side wall of the square-shell cell 4, it can capture the minute deformation caused by the bulging of the square-shell cell 4 in real time and convert the deformation into an electrical signal.

[0033] Pressure sensor 12 is a miniature piezoresistive sensor that captures pressure changes in the prismatic battery cell 4.

[0034] The miniature electrochemical gas sensing unit 14 is specifically designed to detect characteristic gases of thermal runaway, such as CO and HF.

[0035] The selectively breathable membrane 15 is a special composite membrane in the prior art that allows only characteristic gases to pass through while blocking water vapor and dust from entering, thus extending the service life of the micro electrochemical gas sensing unit 14.

[0036] The bottom of the module cover plate 2 has a continuous channel 16, which extends along the arrangement direction of the square-shell battery cell 4, and a temperature-sensing fiber optic sensor 17 is installed inside.

[0037] The continuous channel 16 is an integrally formed groove structure at the bottom of the module cover plate 2, ensuring full coverage of the safety valve 5 area of ​​all square-shell cells 4.

[0038] The temperature-sensing fiber optic sensor 17 is a distributed fiber optic cable, which can realize real-time temperature monitoring of each square-shell cell 4 and accurately locate the square-shell cell 4 that is in thermal runaway.

[0039] The continuous channel 16 covers multiple safety valve 5 areas. The continuous channel 16 has a heat-conducting layer 18, an embedding layer 19 and a heat dissipation layer 20 fixedly attached from bottom to top. The temperature-sensing fiber optic sensor 17 is embedded inside the embedding layer 19.

[0040] The thermal conductive layer 18 is a flexible graphite sheet, and its bottom is closely attached to the safety valve 5 area on the top of the square-shell battery cell 4, which can quickly conduct the heat in the early stage of thermal runaway of the battery cell to the temperature-sensing fiber optic sensor 17.

[0041] The mounting layer 19 is made of high-temperature resistant silicone and has an internal fiber optic groove adapted to the temperature-sensing fiber optic sensor 17. The groove is filled with thermally conductive silicone, which not only fixes the position of the fiber optic cable but also improves the heat conduction efficiency.

[0042] The heat dissipation layer 20 is an aluminum alloy honeycomb panel, which can quickly dissipate the heat accumulated in the channel and avoid local heat accumulation affecting the temperature measurement accuracy.

[0043] A control circuit 21 is installed on the module housing 1. The control circuit 21 is electrically connected to the acoustic sensor 8, pressure sensor 12, deformation strain gauge 13, micro electrochemical gas sensing unit 14 and temperature-sensing fiber optic sensor 17.

[0044] The control circuit 21 is integrated in the waterproof box outside the module housing 1. It has a built-in main control chip and algorithm firmware, which can synchronously receive monitoring signals from various sensors. It can accurately locate the faulty square-shell cell 4 through acoustic fingerprint matching and time difference positioning technology. It can realize the first-level (physical bulging), second-level (precursor to thermal runaway), and third-level (thermal runaway outbreak) graded early warning through the linkage judgment of multiple signals such as temperature, pressure, deformation and gas. The control circuit 21 has a reserved CAN bus interface, which can communicate with the battery management system (BMS) to realize the real-time uploading of early warning signals.

[0045] When the square-shell battery cell 4 is running, the temperature-sensing fiber optic sensor 17 captures the temperature of the area of ​​the safety valve 5 through the heat-conducting layer 18. The deformation strain gauge 13 and pressure sensor 12 of the composite sensor simultaneously monitor the side wall deformation and bulging pressure of the square-shell battery cell 4. The micro electrochemical gas sensing unit 14 senses the characteristic gas of pyrolysis. The acoustic sensor 8 is always on standby, and the sound-absorbing cotton 7 filters the background noise.

[0046] If the square-shell battery cell 4 shows signs of thermal runaway (abnormal temperature, excessive deformation pressure, or release of characteristic gas), or if the safety valve 5 opens to release gas, each sensor will quickly collect the corresponding signal and transmit it to the control circuit 21.

[0047] The control circuit 21 uses acoustic fingerprint matching and time difference positioning to locate the faulty square-shell battery cell 4, and combines temperature, pressure and gas multi-signal linkage to determine the thermal runaway level.

[0048] The control circuit 21 outputs a level 1 (physical bulge), level 2 (precursor to thermal runaway), or level 3 (thermal runaway outbreak) warning signal, and simultaneously uploads it to the BMS via the CAN bus to complete the warning closed loop.

[0049] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A lithium battery thermal runaway early warning device based on gas pressure, battery deformation and cable-type temperature sensing, comprising a module housing (1), wherein a module cover plate (2) is detachably installed on the top of the module housing (1), and a cell bracket (3) is detachably fixedly connected inside the cover plate (2), wherein multiple square-shell cells (4) are snapped into the cell bracket (3), and a safety valve (5) is installed at the exhaust port of the square-shell cells (4), characterized in that, Acoustic sensors (8) are installed on both sides of the module housing (1); A composite sensor is clamped between two adjacent square-shell cells (4). The composite sensor includes a pressure sensor (12), a deformation strain gauge (13), and a micro electrochemical gas sensing unit (14). The module cover plate (2) has a continuous channel (16) at the bottom. The continuous channel (16) extends along the arrangement direction of the square shell cell (4) and is equipped with a temperature-sensing fiber optic sensor (17).

2. The lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing according to claim 1, characterized in that, Mounting seats are installed on both sides of the module housing (1). A protective shell (6) is fixedly connected inside the mounting seat. The acoustic sensor (8) is installed inside the protective shell (6). Sound-absorbing cotton (7) is filled between the protective shell (6) and the acoustic sensor (8).

3. The lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing according to claim 2, characterized in that, The exhaust port edge of the square-shell battery cell (4) is provided with a micro-serrated guide groove (9). The tooth pitch of the micro-serrated guide groove (9) on different square-shell battery cells (4) is not consistent. An exhaust guide edge (10) is integrally formed on the outer side of the exhaust port of the square-shell battery cell (4) to guide the gas flowing through the safety valve (5) to the acoustic sensor (8).

4. A lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing according to claim 1, characterized in that, The composite sensor includes a substrate (11), a pressure sensor (12) mounted in the middle of the substrate (11), two strain gauges (13) mounted on opposite sides of the substrate (11), the strain gauge (13) away from the substrate (11) attached to the sidewall of the same side square-shell cell (4), the sensing end of the pressure sensor (12) being connected to one strain gauge (13), two micro electrochemical gas sensing units (14) mounted on opposite sides of the substrate (11), and a selectively permeable membrane (15) fixedly connected to the side of the micro electrochemical gas sensing unit (14) away from the substrate (11).

5. A lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing according to claim 1, characterized in that, The continuous channel (16) covers multiple safety valve (5) areas. The continuous channel (16) is fixedly attached with a heat-conducting layer (18), an embedding layer (19) and a heat dissipation layer (20) from bottom to top. The temperature-sensing fiber optic sensor (17) is embedded inside the embedding layer (19).

6. A lithium battery thermal runaway early warning device based on gas pressure, battery deformation, and cable-type temperature sensing according to claim 1, characterized in that, The module housing (1) is equipped with a control circuit (21), which is electrically connected to the acoustic sensor (8), pressure sensor (12), strain gauge (13), micro electrochemical gas sensing unit (14) and temperature-sensing fiber optic sensor (17).

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