In-situ correlation testing device for internal temperature field and crystal structure evolution of soft package battery

Abstract

The utility model discloses in-situ correlation testing device of soft package battery internal temperature field and crystal structure evolution belongs to the testing and safety technical field of secondary battery, including test cavity, and the X-ray transmission window of coaxial alignment is set up on the side wall of opposite two sides of test cavity, and the inside of test cavity is centrally provided with sample bearing clamp, and the surface of sample bearing clamp is provided with a plurality of recesses of temperature sensor shape matching, and the inner wall of test cavity is provided with temperature control regulator, and X-ray diffraction subassembly and electrochemistry workstation of being set up with the electrode of soft package battery through electric connection are provided outside test cavity. The utility model is applicable to in the electrochemistry cycle process, and the space-time coupling relation between the microcosmic process of formation, evolution and electrode material phase change, structure damage etc. of battery internal temperature field is monitored synchronously and in-situ.

Description

Technical Field

[0001] This utility model relates to the field of testing and safety technology for secondary batteries, and in particular to an in-situ correlation testing device for the internal temperature field and crystal structure evolution of pouch batteries. Background Technology

[0002] The performance, lifespan, and safety of a battery fundamentally depend on its complex multiphysics coupling behavior, among which the interaction between the thermal field and the crystal structure is particularly critical. During charging and discharging, a complex temperature field forms inside the battery due to electrochemical reactions, latent heat of phase transition, and ohmic heat. Local overheating can accelerate material phase transitions, cause unstable growth and rupture of interfacial films, cracking of active material particles, and even eventual thermal runaway. In-situ X-ray diffraction (XRD) is a powerful microscopic detection method for real-time observation of the dynamic evolution of the crystal structure of electrode materials. However, existing technologies have significant limitations: on the one hand, conventional in-situ XRD testing lacks the ability to measure the true internal temperature of the battery, especially the spatial distribution of the temperature field, relying mostly on limited external temperature measurement points and failing to reflect the formation and evolution of internal hot spots; on the other hand, independent battery thermal imaging or temperature measurement techniques are difficult to synchronize and correlate accurately in time and space with XRD structural analysis that can penetrate the battery package and achieve crystal-scale resolution.

[0003] Therefore, developing an integrated device and analysis method that can synchronously correlate in-situ monitoring of the internal temperature field distribution of a battery with in-situ observation of crystal structure evolution under controlled environmental conditions is of vital scientific and engineering value for fundamentally understanding the coupling chain of "heat generation-heat transfer-structural response" inside a battery, identifying microstructural precursors of thermal runaway, and establishing accurate thermal management models. Utility Model Content

[0004] The purpose of this invention is to provide an in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch battery, solving the problems in the background technology. It is suitable for synchronously and in-situ monitoring the spatiotemporal coupling relationship between the formation and evolution of the internal temperature field of the battery and microscopic processes such as phase transitions and structural damage of electrode materials during electrochemical cycling.

[0005] To achieve the above objectives, this invention provides an in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch battery. The device includes a test chamber with coaxially aligned X-ray transmission windows on its side walls on opposite sides. A sample holder is centrally located inside the test chamber, and its surface has several grooves matching the shape of a temperature sensor. A temperature controller is located on the inner wall of the test chamber. Additionally, an X-ray diffraction assembly and an electrochemical workstation electrically connected to the pouch battery electrodes are located outside the test chamber. This electrochemical workstation is used to execute charge / discharge procedures and collect electrochemical data.

[0006] Preferably, the temperature sensor is a thin-film thermocouple, a thin-film resistance temperature detector, or a fiber Bragg grating temperature sensor; the detection end of the temperature sensor is located in the groove, and multiple temperature sensors are electrically connected to an external temperature acquisition instrument.

[0007] Preferably, the test chamber wall is provided with a heat insulation layer, which is an aerogel layer, a vacuum heat insulation plate layer, or a low thermal conductivity composite ceramic material layer.

[0008] Preferably, the temperature controller is a Peltier thermoelectric cooler, an embedded resistance heating film, or a microchannel liquid cooling circulation system.

[0009] Preferably, the grooves on the sample carrier fixture for fixing the temperature sensor are positioned to match the tab area, electrode center area, and electrode edge area corresponding to the soft-pack battery when it is clamped.

[0010] Preferably, the sealing sheet for the X-ray transmission window is a graphene film sealing sheet, a beryllium film sealing sheet, a polyimide film sealing sheet, or an aluminum-plastic film sealing sheet, which is fixedly sealed at the opening of the X-ray incident window of the test cavity.

[0011] Preferably, it also includes a multi-channel control computer; the multiple output ports of the multi-channel control computer are respectively connected to the control terminal of the temperature controller and the control terminal of the X-ray diffraction component via cables.

[0012] Preferably, the test chamber has several through holes on its wall, through which the signal lines of the temperature sensor, the control lines of the temperature controller, and the electrode connection lines of the pouch battery pass through the walls of the test chamber.

[0013] Therefore, the in-situ correlation testing device for the internal temperature field and crystal structure evolution of the soft-pack battery described above has the following beneficial effects:

[0014] 1. This invention employs an integrated testing chamber design, directly integrating distributed temperature sensors into preset positions on the sample-carrying fixture. Simultaneously, a temperature controller is integrated into the chamber wall, and a dedicated X-ray transmission window is provided. This allows the battery sample's internal temperature signal, external X-ray diffraction signal, and electrochemical signal to be acquired from the same location and at the same time reference under a controlled temperature environment. In particular, the use of an external multi-channel control computer to uniformly trigger the hardware of each acquisition device ensures strict spatiotemporal consistency of all data, providing a reliable foundation for subsequent correlation analysis.

[0015] 2. This invention features temperature sensor mounting positions on the sample carrier fixture, matched to the key battery regions at the tabs, center, and edges. This allows the temperature sensors to directly monitor the thermal state changes of specific micro-regions within the battery. The temperature signal corresponds in real-time with the crystal structure information of the same micro-region obtained through accurately aligned X-ray windows. This enables the device to directly capture the dynamic correlation between localized overheating and specific crystal structure changes during battery charging and discharging, thus providing an irreplaceable experimental method for analyzing the local origins of battery failure.

[0016] 3. By integrating the heat insulation layer into the test chamber wall and combining it with an active temperature controller, this device can provide a stable, uniform, and isolated temperature environment for the battery sample during the experiment, greatly reducing the impact of external thermal interference on the accuracy of in-situ measurements and ensuring the authenticity and validity of the collected data.

[0017] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the test chamber of this utility model;

[0019] Figure 2 This is a schematic diagram showing the arrangement of the array of temperature sensors in this utility model;

[0020] Figure 3 This is an integrated schematic diagram of the present invention;

[0021] Figure 4 The device of this invention is used to detect the XRD feature patterns of a battery during the charging and discharging stages.

[0022] Figure 5 The device of this invention detects the voltage curve and internal temperature of the battery during the same time period of the charging and discharging phase. (a) is the voltage curve of the battery during the charging and discharging phase, and (b) is the internal temperature of the battery during the charging and discharging phase.

[0023] Annotation instructions:

[0024] 1. Test chamber; 2. X-ray transmission window; 3. Sample holder; 4. Wire hole; 5. Temperature controller; 6. Insulation layer; 7. Temperature sensor; 8. Soft-pack battery; 9. Multi-channel control computer; 10. Electrochemical workstation; 11. X-ray diffraction assembly; 111. X-ray source; 112. Two-dimensional detector; 12. Temperature acquisition instrument. Detailed Implementation

[0025] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] The mechanical assembly and fixing of each component in this utility model device are achieved using conventional mechanical connection methods in the art, such as bolt connections and welding. Electrical wiring is led out through lead-in holes in the cavity wall and treated with standard sealed connectors. Various devices (such as computers, temperature controllers, and X-ray diffraction components) are connected via their standard interfaces using conventional cables. Those skilled in the art can select specific components and standard connection methods of conventional models according to actual needs, without changing the structure defined by this utility model.

[0028] like Figure 1 As shown, this invention provides an in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell 8, the core of which is a test chamber 1. This test chamber 1 is typically made of metal, and two coaxially aligned openings are precisely machined on its opposite side walls, serving as X-ray transmission windows 2. The X-ray transmission windows 2 are fixedly sealed with sealing sheets that have low X-ray absorption, such as beryllium sheets, polyimide films, or aluminum-plastic films, to ensure that X-rays can efficiently penetrate the chamber walls.

[0029] Inside the test chamber 1, a sample holder 3 is centrally located to hold and fix the pouch cell 8 to be tested. Several regularly shaped grooves are machined on the surface of the sample holder 3, for example, at specific locations on the upper and / or lower surfaces. The shape of these grooves matches the shape of the probe end of the temperature sensor 7 to be installed. The positions of the grooves ensure that, after the battery is clamped and fixed, they correspond to the tab connection area, the electrode center area, and the electrode edge area on the battery surface, respectively. The wires connecting the electrodes of the pouch cell 8 are led out through the wire hole 4 to the outside of the test chamber 1 and connected to an external electrochemical workstation 10. The electrochemical workstation 10 is used to perform programmed charge and discharge and simultaneously acquire voltage, current, and capacity data.

[0030] Temperature sensor 7 is installed in the aforementioned groove, presenting as follows: Figure 2 The array arrangement is shown. The temperature sensor 7 can be a miniature sensing element such as a thin-film thermocouple, a thin-film resistance temperature detector, or a fiber Bragg grating temperature sensor. The probe end of the temperature sensor 7 is attached to the groove, allowing for stable thermal contact with the battery casing surface when the battery is clamped by the sample carrier 3. The signal lines of the temperature sensor 7 converge and are led out of the chamber through a dedicated wire hole 4 on the wall of the test chamber 1. One of the data lines of the temperature sensor 7 is connected to a temperature acquisition instrument 12.

[0031] The electrodes of the clamped pouch cell 8 are connected to an electrochemical workstation 10 via wires. The test leads of the workstation are also led out to the outside of the test chamber 1 through the wire hole 4 or a separate sealed interface.

[0032] A temperature controller 5, such as a Peltier thermoelectric cooler, an embedded resistance heating film, or an integrated microfluidic liquid cooling circulation system, is fixedly installed on the inner wall of the test chamber 1 to directly heat or cool the environment inside the chamber. To improve the thermal stability of the chamber and reduce external environmental interference, a thermal insulation layer 6 is laminated inside the wall structure of the test chamber 1. This thermal insulation layer 6 can be made of aerogel, vacuum insulation plate, or composite ceramic material with low thermal conductivity.

[0033] An X-ray diffraction assembly 11 is provided outside the test chamber 1. The assembly includes an X-ray source 111 and a two-dimensional detector 112, both of which are precisely aligned with the X-ray transmission window 2.

[0034] To achieve synchronous control of the actions of multiple devices throughout the testing process, this device also includes an external multi-channel control computer 9, as shown in the overall integration diagram. Figure 3As shown. The multi-channel control computer 9 integrates a high-precision hardware synchronization controller based on FPGA (Field Programmable Gate Array) as the core clock reference for the entire system. The panel of the multi-channel control computer 9 is equipped with multiple physical output ports, including a BNC coaxial interface, an RS485 serial port, and an RJ45 Ethernet port. The multiple output ports of the multi-channel control computer 9 are physically connected to the control signal input terminal of the temperature controller 5, the control terminal of the external X-ray diffraction component 11, the input and output terminals of the temperature sensor 7, and the electrochemical workstation 10 in a one-to-one manner through shielded cables or coaxial cables. It outputs TTL level pulse signals as hardware trigger signals, combined with Modbus RTU or SCPI (Programmable Instrument Standard Command) software communication protocols, and uses the high-frequency reference sampling clock generated by the internal hardware synchronization controller to coordinate the response timing of each external component. This ensures that the single or continuous scanning action of the X-ray diffraction component 11, the specific potential / capacity trigger point of the electrochemical workstation 10, and the high-speed sampling clock of the temperature sensor 7 maintain sub-second time synchronization accuracy.

[0035] After completing the above hardware connections, this device can be operated for testing as follows:

[0036] 1. Test Preparation and Device Connection. First, prepare the device of this invention, the core of which is a test chamber. Coaxially aligned X-ray transmission windows are opened on both sides of the chamber, and the windows are sealed with beryllium plates or polyimide films. A sample carrier fixture is centrally located inside the chamber, and the surface of the sample carrier fixture is machined with several grooves, the positions of which correspond to the battery's tabs, center, and edge areas.

[0037] A pouch cell was used as the test sample. In this embodiment, the pouch cell was held in a sample holder. The pouch cell was assembled into a full cell by matching an NCM811 positive electrode aluminum foil current collector with a graphite negative electrode. A grid-like array of thin-film thermocouples was attached to the groove of the sample holder. In this embodiment, the thin-film thermocouple array was placed on the back side of the NCM811 positive electrode aluminum foil current collector.

[0038] The battery is installed and clamped in the sample holder, with the battery electrodes connected to wires extending from the cavity's through-hole. These wires are then externally connected to an electrochemical workstation. Simultaneously, the thin-film thermocouple signal wire on the back of the battery is also led out through a through-hole in the cavity wall and connected to an external temperature acquisition instrument.

[0039] The Peltier thermoelectric cooler fixed to the inner wall of the cavity and the aerogel insulation layer composited within the cavity wall are prepared. Finally, an external multi-channel control computer is connected via cables to the external trigger ports of the Peltier thermoelectric cooler, the two-dimensional detector, the electrochemical workstation, and the temperature acquisition instrument.

[0040] 2. Test execution and data synchronization acquisition. After completing the hardware connection, operate the device according to the following steps:

[0041] Environmental settings: The ambient temperature inside the test chamber was set and stabilized at 45°C using a Peltier semiconductor cooling chip.

[0042] Synchronous program startup: The operation control computer sends a unified trigger signal. Under this signal:

[0043] The electrochemical workstation began performing a programmed charge-discharge cycle at a 2C rate on the battery.

[0044] The X-ray diffraction assembly begins a continuous two-dimensional diffraction scan of the battery's positive electrode region at a preset high time resolution (1 frame / minute).

[0045] The temperature acquisition instrument begins to synchronously record the temperature time sequence data of all measuring points of the thin-film thermocouple array.

[0046] 3. Data Output and Observable Phenomena. Through the above process, the device synchronously outputs a three-dimensional data stream with a strictly unified time reference: voltage-current curves, temperature change curves at multiple points in the internal space, and a sequence of two-dimensional X-ray diffraction patterns of the cathode material.

[0047] The results of the correlation analysis of these synchronized data are as follows: Figure 4 as well as Figure 5 As shown, the following phenomena can be observed: Figure 5 As shown in (a), when charged to approximately 4.2V, Figure 5 The synchronous data in (b) reveals a distinct localized temperature pulse within the battery. Simultaneously, the X-ray diffraction pattern sequence at this moment is as follows: Figure 4 The results show that the intensity of the characteristic diffraction peaks corresponding to the H2-H3 phase transition in NCM811 material is weakened and broadened. These simultaneously observed phenomena indicate that the device can effectively and directly correlate the thermal behavior of phase transition reaction heat with the structural evolution of crystal structure damage in space and time, providing intuitive experimental evidence for understanding the failure mechanism of materials at high temperatures and high potentials.

[0048] It should be noted that the specific battery material (NCM811), test temperature (45℃), charge / discharge rate (2C), and observed phenomena mentioned above are merely examples. The testing device claimed in this utility model is versatile in that, through the integrated hardware structure and synchronous triggering connection method described above, it can be applied to perform similar in-situ, synchronous, multi-physics field observations of different types of batteries under various operating conditions.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. An in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell, characterized in that, The test chamber includes a test chamber with coaxially aligned X-ray transmission windows on its side walls on opposite sides; a sample holder is centrally located inside the test chamber, and several grooves matching the shape of the temperature sensor are provided on the surface of the sample holder; a temperature controller is provided on the inner wall of the test chamber. X-ray diffraction components are located outside the test chamber; An electrochemical workstation electrically connected to the electrodes of a pouch cell.

2. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a soft-pack battery according to claim 1, characterized in that, The temperature sensor is a thin-film thermocouple, a thin-film resistance temperature detector, or a fiber Bragg grating temperature sensor; the detection end of the temperature sensor is located in the groove, and multiple temperature sensors are electrically connected to an external temperature acquisition instrument.

3. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a soft-pack battery according to claim 1, characterized in that, The test chamber is equipped with a heat insulation layer in its wall, which can be an aerogel layer, a vacuum insulation board layer, or a low thermal conductivity composite ceramic material layer.

4. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell according to claim 1, characterized in that, The temperature controller is a Peltier semiconductor refrigeration chip and an embedded resistance heating film.

5. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell according to claim 1, characterized in that, The grooves on the sample carrier fixture used to fix the temperature sensor are positioned to match the tab area, electrode center area, and electrode edge area corresponding to the soft-pack battery when it is clamped.

6. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell according to claim 1, characterized in that, The sealing sheet for the X-ray transmission window is a graphene film sealing sheet, a beryllium film sealing sheet, a polyimide film sealing sheet, or an aluminum-plastic film sealing sheet, which is fixedly sealed at the X-ray entrance window opening of the test chamber.

7. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell according to claim 1, characterized in that, It also includes a multi-channel control computer; the multiple output ports of the multi-channel control computer are connected to the control terminal of the temperature controller and the control terminal of the X-ray diffraction component via cables.

8. The in-situ correlation testing device for the internal temperature field and crystal structure evolution of a pouch cell according to claim 1, characterized in that, Several wire holes are provided on the wall of the test chamber. The signal wires of the temperature sensor, the control wires of the temperature controller, and the electrode connection wires of the soft-pack battery pass through the wire holes to the wall of the test chamber.

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