A marine shaking cable driven containment battery thermal runaway test system and method

Abstract

The present application relates to the technical field of lithium ion battery safety testing, in particular to a marine oscillating cable driven closed battery thermal runaway test system and method, the system comprising a support frame, a six-degree-of-freedom flexible cable driving module, a confined space closed test cabin and an upper computer motion control system. The closed test cabin is a sealable rigid cabin body, six active flexible cables are arranged in space and connected with the cabin body external lugs, forming an edge mounting topology, and the flexible cables are located outside the cabin body and do not pass through the cabin wall. The present application uses flexible cable driving to realize large-stroke heave, roll, pitch and coupled motion, simulating marine oscillation dynamic load; the cabin body adopts static sealing design, reducing the risk of high-pressure toxic smoke leakage through the moving sealing part; the cross-topology structure improves the anti-yaw ability of the cabin body under the recoil of thermal runaway ejecta, solving the contradiction between large-stroke marine environment simulation and high-pressure closed safety, and being suitable for thermal runaway dynamic testing of battery monomers, modules or small energy storage components.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery safety testing technology, specifically a marine swaying cable-driven sealed battery thermal runaway testing system and method. Background Technology

[0002] With the rapid development of new energy ships, the safety issues of large-capacity lithium-ion batteries in extreme deep-sea environments are becoming increasingly prominent. When ships encounter severe sea conditions, the complex dynamic loads such as violent turbulence, rolling, and weightlessness caused by giant waves can lead to electrolyte sloshing, electrode misalignment, and structural stress concentration inside the battery, which can easily induce or accelerate thermal runaway. To study this coupling mechanism, an experimental system capable of reproducing the marine rolling environment in a confined space is urgently needed. The marine rolling environment described in this invention refers to the single-degree-of-freedom or multi-degree-of-freedom coupled dynamic load environment generated by ships, offshore platforms, or offshore energy storage equipment under the action of waves, including roll, pitch, bow, heave, sway, and sway. The marine rolling environment can be generated by regular waves, irregular waves, target wave spectra, or preset motion parameters, and transformed into the spatial posture motion of a confined space test chamber through a cable-driven closed experimental system.

[0003] In existing technologies, mainstream lithium-ion battery thermal runaway testing devices mostly employ static, sealed containers, such as constant-volume incendiary bombs or explosion-proof boxes. These are primarily used to study temperature rise, pressure buildup, and gas generation behavior under conditions without dynamic loads. However, they are insufficient to simulate the disturbance effects of inertial forces on internal short circuits, the trajectory of thermal runaway ejecta, and the high-pressure flue gas field under ocean swaying conditions. Some studies have attempted to mount the test chamber on a Stewart rigid six-degree-of-freedom platform, but such platforms are limited by the physical length of the pushrods, resulting in a limited heave stroke. This makes it difficult to reproduce large heaves and transient weightlessness conditions, and the rigid linkages are susceptible to additional loads under deflagration impacts.

[0004] While cable-driven parallel robots offer the advantage of long stroke, their application in driving sealed pressure chambers often requires the load-bearing flexible cables or moving parts to pass through the chamber walls, creating potential points of dynamic seal failure. Furthermore, thermal runaway of lithium-ion batteries generates high-temperature, high-pressure fumes containing harmful components. Traditional cable-driven dynamic seals are at risk of failure under high-frequency reciprocating friction of the steel cables, leading to toxic gas leaks. In addition, the wiring in traditional cable-driven systems is mostly suspended externally, making them prone to interference and entanglement with the load-bearing cables during violent multi-dimensional swaying, and potentially causing yaw or motion coupling errors due to the recoil of thermal runaway ejecta.

[0005] Therefore, existing technologies present a contradiction between "simulating large-stroke marine swaying environment" and "high-pressure toxic confined space". There is a lack of a dynamic testing system and method for lithium-ion batteries that can simultaneously realize large-stroke six-degree-of-freedom dynamic load reproduction, closed pressure safety testing, thermal runaway parameter acquisition, and safe handling of toxic gases after the experiment. Summary of the Invention

[0006] The purpose of this invention is to provide a marine swaying cable-driven sealed battery thermal runaway testing system and method to solve the problem that existing lithium-ion battery thermal runaway testing devices cannot simultaneously achieve long-stroke marine dynamic load reproduction, high-pressure toxic product sealed safety testing, and dynamic thermal runaway parameter acquisition.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A marine swaying cable-driven sealed battery thermal runaway testing system includes:

[0009] Supporting framework;

[0010] The six-degree-of-freedom flexible cable drive module includes six servo motors fixedly installed on the top of the support frame and six active flexible cables driven by them;

[0011] The confined space sealed test chamber is a sealable rigid chamber with six connecting lugs on the upper edge of its external top surface or side wall.

[0012] The host computer motion control system is used to generate the hull motion trajectory based on the target ocean swaying environment and to calculate the length commands of the six active flexible cables.

[0013] The six active flexible cables are led out through fixed pulleys installed at the top corners of the support frame, arranged in a cross pattern in space and connected to the six connecting lugs respectively, forming a spatial cross-edge mounting topology; all six active flexible cables are located outside the confined space sealed test chamber and do not pass through the walls of the closed rigid chamber.

[0014] As a further aspect of the present invention: the bottom center of the confined space sealed test chamber is provided with a statically sealed explosion-proof cable sealing joint, and a flexible dynamic signal pipe passes through the joint to connect the sensors inside the chamber with the external data acquisition equipment.

[0015] As a further aspect of the present invention: the top of the confined space sealed test chamber is provided with a pressure relief explosion-proof plate and an exhaust port with a manual ball valve.

[0016] As a further aspect of the present invention: the pressure relief and explosion-proof disc is an arched metal rupture disc, and the static burst pressure threshold is set to 0.15 MPa to 0.3 MPa.

[0017] As a further embodiment of the present invention: the height of the support frame is 2.0 m to 3.0 m, and the confined space sealed test chamber is a cube or near-cube structure with a side length of 0.3 m to 1.0 m.

[0018] As a further aspect of the present invention: the active flexible cable is a high-strength flexible cable with a diameter of 3 mm to 5 mm.

[0019] As a further aspect of the present invention: the servo motor in the six-degree-of-freedom flexible cable drive module has a rated power of 400 W to 750 W, and is equipped with a planetary reducer with a reduction ratio of 1:10 to 1:30.

[0020] As a further aspect of the present invention: the confined space sealed test chamber is provided with a battery mounting base, a thermal runaway trigger component mounting position, a temperature sensor mounting position, a pressure sensor interface, and a voltage acquisition interface.

[0021] The present invention also provides a method for testing the thermal runaway of a lithium-ion battery using the marine rocking cable-driven sealed battery thermal runaway test system described above, comprising the following steps:

[0022] Step 1: Fix the lithium-ion battery under test and its thermal runaway triggering device in a confined space sealed test chamber, connect the sensor cable to the flexible dynamic signal pipeline, seal the chamber and check the airtightness.

[0023] Step 2: The host computer generates a six-degree-of-freedom motion trajectory command based on the target ocean swaying environment parameters or the target wave spectrum;

[0024] Step 3: The target pose is converted into the length commands of the six active flexible cables in real time through the inverse kinematics algorithm, which drive the servo motor to move the cabin to reproduce the ocean swaying motion;

[0025] Step 4: Trigger thermal runaway of the lithium-ion battery under dynamic load, and simultaneously collect the pressure, temperature, battery voltage and thermal runaway process parameters inside the chamber;

[0026] Step 5: After the experiment, exhaust the remaining toxic gases in the chamber to the washing device through the exhaust port.

[0027] As a further aspect of the present invention: the target wave spectrum in step two is the JONSWAP irregular wave spectrum, and the six-degree-of-freedom motion trajectory of roll, pitch, yaw, heave, sway and sway in the time domain is generated using the amplitude response operator.

[0028] As a further aspect of the present invention: after the toxic gas described in step five is washed and absorbed by the alkaline washing device, the door can only be opened after a preset negative pressure state is formed in the chamber and the concentration of harmful gas is lower than a preset safety threshold.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. Improved compatibility between long-stroke ocean rolling environment simulation and closed-loop safety testing: This invention uses flexible cable drive instead of rigid linkage to simulate heave, roll, pitch, and their coupled motions under ocean rolling conditions. Simultaneously, the closed-loop test chamber adopts a completely statically sealed design, leaving no penetration holes for any moving components. The active flexible cable only pulls on the outside of the chamber, reducing the risk of high-pressure toxic fumes leaking through the moving sealing parts, thus resolving the contradiction between "long-stroke simulation" and "closed-loop safety" in existing technologies.

[0031] 2. Improved anti-yaw capability under the recoil of thermal runaway ejecta: The present invention adopts a topology of six active flexible cables with spatial cross-edge mounting. The cables are X-shaped when projected on the horizontal plane, which converts axial tension into tangential torsional force. The initial yaw torsional stiffness is higher than that of the traditional parallel suspension scheme, which can reduce the risk of large-scale rotational loss of control of the cabin caused by the recoil of thermal runaway ejecta.

[0032] 3. Ensuring reliable data transmission and system security under extreme environments: The flexible dynamic signal pipeline exits through the static sealing joint at the bottom of the compartment, avoiding dynamic seal wear and failure while also accommodating significant bending in six degrees of freedom. A pressure relief and explosion-proof diaphragm is installed at the top of the compartment, which can release pressure when the internal pressure exceeds a set threshold to reduce the risk of overpressure deformation of the compartment. After the experiment, residual toxic gases can be treated by connecting a scrubbing device through the exhaust port. Attached Figure Description

[0033] Figure 1 This is a diagram showing the overall spatial structure and operating status of the marine rocking cable-driven sealed battery thermal runaway test system of the present invention.

[0034] Figure 2 This is an enlarged schematic diagram of the external structure and safety components of a confined space sealed test chamber.

[0035] Figure 3 This is a top view of the topology of the flexible cable space intersecting edges.

[0036] In the diagram: 1. Support frame; 2. Six-DOF flexible cable drive module; 3. Active flexible cable; 4. Confined space sealed test chamber; 41. Chamber metal shell; 42. Connecting lugs; 43. Pressure relief explosion-proof plate; 44. Exhaust port; 5. Flexible dynamic signal pipeline. Detailed Implementation

[0037] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0039] like Figure 1 As shown, the marine swaying cable-driven sealed battery thermal runaway test system of this embodiment includes a support frame 1, a six-degree-of-freedom flexible cable drive module 2, a confined space sealed test chamber 4, a flexible dynamic signal pipeline 5, and a host computer motion control system.

[0040] The support frame 1 is constructed from heavy-duty industrial aluminum profiles and is positioned on the outermost side of the entire system as an external load-bearing structure. In this embodiment, its dimensions are 2.0m × 2.0m × 2.5m. The six-degree-of-freedom flexible cable drive module 2 comprises six AC servo motors and their matching reducers, all fixedly installed on the outer top layer of the support frame 1. Six active flexible cables 3 are led out through ceramic fixed pulleys installed at the top corners of the frame.

[0041] like Figure 1 and Figure 3 As shown, the confined space sealed test chamber 4 is a sealable rigid chamber. In this embodiment, it is a cubic structure with a side length of 0.5m, welded from 1.5mm thick 316L stainless steel. Six connecting lugs 42 are provided on the outer top edge of the chamber. Six active flexible cables 3 are arranged in a crisscross pattern in space and connected to the six connecting lugs 42 respectively, forming a spatial crisscross edge mounting topology. Figure 3 As can be seen from the top view, the projections of the six active flexible cables 3 on the horizontal plane form an X-shaped intersection. This edge mounting design, which is far from the geometric center of the cabin, can generate a large anti-torsional arm.

[0042] like Figure 2 As shown, the metal outer shell 41 of the confined space sealed test chamber 4 is completely sealed, leaving no penetration holes for any moving components. A statically sealed explosion-proof cable sealing joint is provided at the center of the bottom of the chamber. The flexible dynamic signal pipe 5 passes through this joint to export the signals of the internal thermocouples and voltage sensors to the external data acquisition equipment, realizing "external drive and static sealing of the bottom surface".

[0043] The top of the chamber is equipped with a pressure relief and explosion-proof disc 43 and an exhaust port 44 with a manual ball valve. The pressure relief and explosion-proof disc 43 is an arched metal rupture disc made of 316L stainless steel, with a static burst pressure threshold set at 0.2 MPa. This threshold is used to maintain airtightness in the early stages of battery thermal runaway. When the pressure inside the chamber exceeds the set threshold, it ruptures to release pressure, thereby reducing the risk of overpressure deformation of the chamber. The exhaust port 44 is used to connect a vacuum scrubbing pump after the experiment to extract and scrub the toxic fumes containing hydrofluoric acid.

[0044] Dynamic Operation: The host computer generates position and attitude commands based on target ocean rolling environment parameters, such as significant wave height, spectral peak period, roll amplitude, pitch amplitude, and heave amplitude. It then uses an inverse kinematics algorithm to calculate the length changes of the six active flexible cables 3 in real time, driving servo motors to propel the confined space sealed test chamber 4 to reproduce the six-degree-of-freedom ocean rolling motion in the air. Due to the combination of a 2.5m frame and a 0.5m chamber, the system has an effective heave stroke of approximately 0.8m to 0.9m. The active flexible cables 3 only experience tension and friction outside the chamber, preventing the high-pressure, high-temperature mixed gas generated by internal thermal runaway from directly contacting the load-bearing cables.

[0045] Example 1 (Small size, suitable for single-cell batteries)

[0046] The support frame 1 measures 1.5m × 1.5m × 2.0m. The confined space sealed test chamber 4 is a cubic structure with sides of 0.3m, welded from 1.5mm thick 316L stainless steel, and the chamber is completely sealed. Six active flexible cables 3 are made of 3mm diameter ultra-high molecular weight polyethylene fiber rope. Six servo motors, each with a rated power of 400W, are paired with planetary reducers with a reduction ratio of 1:15. The pressure relief and explosion-proof disc 43 has a burst pressure set at 0.15MPa. This configuration has a low moment of inertia and is suitable for simulating high-frequency marine swaying response conditions for lithium-ion battery cell thermal runaway testing.

[0047] Example 2 (Preferred size, suitable for small modules)

[0048] This refers to the embodiment described in the specific implementation plan above. The support frame 1 has dimensions of 2.0m × 2.0m × 2.5m, and the confined space sealed test chamber 4 is a cubic structure with a side length of 0.5m. The six active flexible cables 3 are made of ultra-high molecular weight polyethylene fiber rope with a diameter of 4mm and an outer sheath covered with a high-temperature resistant and flame-retardant sheath. The sheath has a temperature resistance of not less than 300℃ and a flame retardant rating of UL94V-0. The servo motor has a rated power of 750W and is equipped with a planetary reducer with a reduction ratio of 1:20. The burst pressure of the pressure relief and explosion-proof disc 43 is set at 0.2MPa. This configuration achieves a good balance between low-frequency large-amplitude ocean rolling motion and high-frequency small-amplitude vibration response simulation, with an effective heave stroke of approximately 0.8m to 0.9m.

[0049] Example 3 (Large size, suitable for large-capacity energy storage modules)

[0050] The support frame 1 measures 4.0m × 4.0m × 3.0m, and the confined space sealed test chamber 4 is a cubic structure with sides of 1.0m. Six active flexible cables 3 are made of 5mm diameter fine steel wire ropes covered with flame-retardant sheaths. Each servo motor has a rated power of 750W and is paired with a planetary reducer with a reduction ratio of 1:30. The pressure relief and explosion-proof disc 43 has a burst pressure set at 0.3MPa. This configuration is suitable for simulating low-frequency roll, pitch, and heave conditions on ocean-going vessels or offshore energy storage equipment.

[0051] Explanation of the anti-yawing torque principle of the cross-topology: Taking the 0.5m cabin of Example 2 as an example, the six active flexible cables 3 are projected in an X-shape on the horizontal plane. When the thermal runaway ejecta jet or flame jet generates transient yawing torque, due to the cross arrangement, the axial tension of each active flexible cable 3 will generate a tangential component in the horizontal direction. This tangential component multiplied by the cross span forms a restoring torque that resists yawing. Theoretical calculations show that the initial yawing torsional stiffness of the topology of this invention is higher than that of the traditional parallel suspension scheme (the traditional scheme only relies on the gravity swing angle to provide a weak restoring torque, which is usually less than 1 N·m / rad). The cross-topology also helps to reduce cabin yawing and motion coupling errors, allowing the cabin to move according to a preset wave spectrum.

[0052] Specific operating steps of the lithium-ion battery thermal runaway test method (taking Example 2 as an example)

[0053] Step 1: Fix the lithium-ion battery cell, module, or small energy storage component under test and its thermal runaway triggering device to the bottom plate of the sealed test chamber. In this embodiment, the test object is an 18650 type lithium-ion battery, and the thermal runaway triggering method is heating triggering. Connect the K-type thermocouple and voltage acquisition line to the flexible dynamic signal pipeline 5, and lead it out to the data acquisition card through the bottom explosion-proof gland. Close the chamber door and fill it with 0.05MPa compressed air to check for leaks. After confirming that there is no pressure drop, restore it to normal pressure.

[0054] Step 2: The host computer generates motion input based on the target ocean swaying environment parameters. In this embodiment, the host computer introduces the JONSWAP irregular wave spectrum with an effective wave height of 3m and a peak period of 6s. It uses the ship amplitude response operator to generate motion trajectories with six degrees of freedom in the time domain, including roll, pitch, bow, heave, sway, and pitch, with a sampling frequency of 100Hz.

[0055] Step 3: The inverse kinematics algorithm is used to convert the target pose at each moment into the target length of the six active flexible cables in real time. Pulses are sent to the servo drive through EtherCAT communication to control the cabin to move along the preset trajectory. The roll angle can reach ±30° and the heave amplitude can reach ±0.4m.

[0056] Step 4: Under continuous dynamic load, the heating device (100W power) is activated to heat the bottom of the battery. Once the thermocouple detects that the battery surface temperature exceeds 150°C, the rapid temperature rise phase of thermal runaway begins. Simultaneously, data on cabin pressure, multi-point temperature, battery voltage, and deflection of the thermal runaway ejecta jet or flame are collected. The externally mounted active flexible cables 3 continuously provide torsional stiffness, and the cabin yaw response can be controlled within a preset range.

[0057] Step 5: After the thermal runaway reaction ends, the chamber is lowered to the bottom buffer seat. The vacuum cleaning pipeline (containing sodium hydroxide solution, concentration 10wt%) is connected to the exhaust port 44 on the top of the chamber, and the vacuum pump is turned on to remove residual gas from the chamber. The chamber door can only be opened to extract the battery debris after the internal pressure reaches the preset negative pressure range and the concentration of harmful gases is below the preset safety threshold. In this embodiment, the cleaning pipeline contains sodium hydroxide solution with a concentration of 10wt%; the vacuum flow rate is 5L / min; and the harmful gas detection targets include HF gas.

[0058] Comparison Results: The anti-yaw performance of the traditional parallel suspension topology and the X-type cross topology of this invention was compared and analyzed using theoretical mechanics and spatial geometric kinematics. The results show that the traditional scheme has an "under-constrained" defect in the yaw direction, with torsional stiffness approximately zero (relying only on the weak restoring torque provided by the gravity swing angle), resulting in significant rotational runaway under transient torsion. In contrast, the cross topology of this invention directly converts the axial tension of the flexible cable into a tangential force to resist horizontal rotation, thereby improving yaw stiffness, suppressing transient torsional displacement response, and providing clear forward and inverse kinematic solutions for the six degrees of freedom, making it less prone to significant coupling interference between the motions.

[0059] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A test system for thermal runaway of a marine swaying cable-driven sealed battery, characterized in that, include: Supporting framework; The six-degree-of-freedom flexible cable drive module includes six servo motors fixedly installed on the top of the support frame and six active flexible cables driven by them; The confined space sealed test chamber is a sealable rigid chamber with six connecting lugs on the upper edge of its external top surface or side wall. The host computer motion control system is used to generate the hull motion trajectory based on the target ocean swaying environment and to calculate the length commands of the six active flexible cables. The six active flexible cables are led out through fixed pulleys installed at the top corners of the support frame, arranged in a cross pattern in space and connected to the six connecting lugs respectively, forming a spatial cross-edge mounting topology; all six active flexible cables are located outside the confined space sealed test chamber and do not pass through the walls of the closed rigid chamber.

2. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 1, characterized in that, The confined space sealed test chamber has a statically sealed explosion-proof cable sealing joint at the bottom center, through which a flexible dynamic signal pipe connects the sensors inside the chamber to the external data acquisition equipment.

3. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 1, characterized in that, The top of the confined space sealed test chamber is equipped with a pressure relief explosion-proof plate and an exhaust port with a manual ball valve.

4. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 3, characterized in that, The pressure relief and explosion-proof disc is an arched metal rupture disc, and the static burst pressure threshold is set to 0.15 MPa to 0.3 MPa.

5. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 1, characterized in that, The height of the support frame is 2.0 m to 3.0 m, and the confined space sealed test chamber is a cube or near-cube structure with a side length of 0.3 m to 1.0 m.

6. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 1, characterized in that, The active flexible cable is a high-strength flexible cable with a diameter of 3 mm to 5 mm.

7. The marine rocking cable-driven sealed battery thermal runaway testing system according to claim 1, characterized in that, The servo motors in the six-degree-of-freedom flexible cable drive module have a rated power of 400 W to 750 W each, and are paired with planetary reducers with a reduction ratio of 1:10 to 1:

30.

8. The marine rocking cable-driven sealed battery thermal runaway test system according to claim 1, characterized in that, The confined space sealed test chamber is equipped with a battery mounting base, a thermal runaway trigger component mounting position, a temperature sensor mounting position, a pressure sensor interface, and a voltage acquisition interface.

9. A method for testing the thermal runaway of a lithium-ion battery using the marine rocking cable-driven sealed battery thermal runaway test system according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Fix the lithium-ion battery to be tested and its triggering device in a confined space sealed test chamber, connect the sensor cable to the flexible dynamic signal pipeline, seal the chamber and check the airtightness. Step 2: The host computer generates a six-degree-of-freedom motion trajectory command based on the target ocean swaying environment parameters or the target wave spectrum; Step 3: The target pose is converted into the length commands of the six active flexible cables in real time through the inverse kinematics algorithm, which drive the servo motor to move the cabin to reproduce the ocean swaying motion; Step 4: Trigger thermal runaway of the lithium-ion battery under dynamic load, and simultaneously collect the pressure, temperature, battery voltage and thermal runaway process parameters inside the chamber; Step 5: After the experiment, exhaust the remaining toxic gases in the chamber to the washing device through the exhaust port.

10. The lithium-ion battery thermal runaway test method according to claim 9, characterized in that, The target wave spectrum mentioned in step two is the JONSWAP irregular wave spectrum, which uses the amplitude response operator to generate six-degree-of-freedom motion trajectories in the time domain, namely roll, pitch, yaw, heave, sway, and sway.

11. The lithium-ion battery thermal runaway test method according to claim 9, characterized in that, After the toxic gas described in step five is absorbed and treated by the alkaline washing device, the hatch can only be opened after a preset negative pressure is formed inside the chamber and the concentration of harmful gas is lower than a preset safety threshold.

Images