Observation device for in-situ working condition reaction of lithium battery

Abstract

An observation device for in-situ working condition reaction of a lithium battery comprises an outer shell with an outer shell opening in the upper part; the observation cover is arranged on the opening of the outer shell and is provided with a transparent observation window; the battery placing device comprises a lower base, an internal connection tab, a connecting piece, an upper base and an inner shell, the connecting piece is sequentially connected with the lower base, one end part of the internal connection tab and the upper base, the lithium battery section block tab is arranged above the upper base and is in contact connection with the connecting piece, the upper base is connected with the inner shell, and the inner shell is hollow and is used for placing the lithium battery section block; the other end part of the internal connection tab is arranged at the outer side part of the inner shell; an avoiding hole is formed in the side part of the outer shell, and the external tab penetrates through the avoiding hole and is in contact connection with the other end part of the internal tab; the method can realize in-situ working condition observation of an actual battery, has the advantages of high reliability, long-time observation, multi-modal observation and the like, and can deeply explore complex multi-scale and multi-modal characteristic evolution in the actual battery charging and discharging process.

Description

Technical Field

[0001] The present invention relates to the technical field of material testing, and in particular to an observation device for in-situ working condition reactions of a lithium battery. Background Art

[0002] In the context of the increasing depletion of traditional fossil energy and the great changes in energy structure, lithium batteries with advantages such as high energy density, long cycle life, low cost, and green recyclability have been widely used in transportation, consumer electronics, energy storage systems, smart wearables and other life and production fields. In recent years, with the rapid development of battery manufacturing technology and battery characterization technology, the correlation research on the macro performance and micro reaction mechanism of lithium batteries has gradually deepened. A deep understanding of the various reaction behaviors and related mechanisms occurring within the lithium battery system can promote revolutionary progress in lithium battery manufacturing technology.

[0003] As an important type of energy storage and conversion device, lithium battery is essentially a special chemical reactor. As a whole chemical system, the battery also has special "three transmissions and one reverse" behavior during use: ion transmission, electron transmission, heat transfer and electrochemical reaction. In addition, from the perspective of materials, lithium batteries are composed of four key materials, namely positive electrode, negative electrode, diaphragm and electrolyte, and other functional structural parts. Therefore, the working process of the battery system is actually a "three transmissions and one reverse" behavior occurring in the four three-dimensional spaces of positive electrode, negative electrode, diaphragm and electrolyte. There are changes in multiple physical and chemical elements such as element composition, crystal structure, spatial morphology, element valence state, mechanical stress, thermal field, electric field, etc. in the multi-scale space of particle-electrode-battery. A deep understanding of the multi-factor structure-activity relationship between the above microscopic-mesoscopic-macroscopic multi-factors and the overall performance of the battery system is the key to the research on the mechanism of lithium batteries and the design, development and manufacturing of batteries. Currently, there are a variety of ex-situ and in-situ characterization techniques to study the various behaviors of various elements in lithium batteries, mainly reflected in the element valence and morphology structure research on the synchrotron radiation platform, the morphology-element composition-crystal structure ex-situ research on the scanning-transmission electron microscope platform, the phase structure research on the Raman optical platform, the phase change research on the X-ray diffraction platform, and the three-dimensional structure research on the computed tomography imaging platform and the synchrotron radiation X-ray platform.

[0004] However, for the same actual battery reaction system, it is necessary to simultaneously observe and characterize the multi-factor behavior of the battery reaction and construct a multi-factor structure-activity relationship under in-situ conditions to understand the correlation between the microscopic reaction mechanism and the macroscopic battery performance. There are very few studies and characterization technologies in this area, and the analysis of the structure-activity relationship of multi-factor factors is even more challenging. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a novel structured observation device for in-situ working condition reactions of lithium batteries.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] An observation device for in-situ working condition reaction of a lithium battery, comprising:

[0008] An outer shell, wherein the outer shell is hollow and has an outer shell opening at the top;

[0009] An observation cover, which is arranged on the opening of the outer shell, and the observation cover has a transparent observation window;

[0010] A battery placement device, comprising: a lower base, an inner pole ear, a connector, an upper base, and an inner shell, wherein the connector sequentially connects the lower base, one end of the inner pole ear, and the upper base, a pole ear of a lithium battery cross-section block can be arranged above the upper base and contact and connect with the connector, the upper base is connected to the inner shell, the inner shell is hollow and is used to place a lithium battery cross-section block, and the other end of the inner pole ear is arranged on the outer side of the inner shell;

[0011] The external pole ear is provided with a clearance hole on the side of the outer shell, and the external pole ear is passed through the clearance hole to contact and connect with the other end of the internal pole ear.

[0012] In one embodiment, it also includes an upper nut, which is arranged above the upper base and connected to the connecting piece, and the lithium battery cross-section block tab can be arranged between the upper nut and the upper base.

[0013] In one embodiment, it further includes an upper gasket, which is arranged above the upper base and in contact with the upper base, and the lithium battery cross-section block tab can be arranged between the upper gasket and the upper nut.

[0014] In one embodiment, it further includes a lower nut, which is arranged below the lower base and connected to the connecting member, and one end of the internally connected pole ear is arranged between the lower nut and the lower base.

[0015] In one embodiment, it further includes a lower gasket, which is arranged above the lower base and in contact with the lower base, and one end of the internally connected pole ear is arranged between the lower gasket and the lower nut.

[0016] In one embodiment, one end of the internally connected tab has a tab through hole, and the connecting member passes through the tab through hole.

[0017] In one embodiment, it further includes a lifting seat, the lifting seat includes a lifting nut and a lifting seat body, the lifting nut is screwed under the lifting seat body, and the lifting seat body is connected to the lower base.

[0018] In one embodiment, the observation cover includes an observation cover upper portion, a transparent observation window and an observation cover lower portion, and the transparent observation window is arranged between the observation cover upper portion and the observation cover lower portion.

[0019] In one embodiment, it also includes an observation cover upper sealing ring, which is arranged between the upper part of the observation cover and the transparent observation window, and / or, it also includes an observation cover lower sealing ring, which is arranged between the lower part of the observation cover and the transparent observation window.

[0020] In one embodiment, it also includes a first sealing ring of the outer shell, which is arranged between the upper part of the outer shell and the observation cover, and / or, it also includes a second sealing ring of the outer shell, which is arranged between the side of the outer shell and the external pole ear.

[0021] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0022] The present invention discloses an observation device for in-situ working condition reactions of lithium batteries for in-situ synchronous detection of reactions of lithium battery cross-section blocks. By arranging a battery placement device, stable placement of the battery block of the lithium battery cross-section inside an outer shell is ensured, laying a foundation for subsequent observations. In-situ working condition dynamic observations can be performed on the macroscopic, mesoscopic and microscopic organizational morphology, charge and discharge behavior, structure and composition and other physical and chemical characteristics of the lithium battery as a whole, especially the overall cross-section of the lithium battery, at multiple scales of battery, electrode and particle, which provides conditions for in-depth exploration of the overall reaction behavior of the battery system, especially the electrode reaction process, and can systematically understand the multi-scale and multi-element structure-activity factor relationships of multiple reaction behaviors of the battery system throughout its life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of an observation device for in-situ working condition reaction of a lithium battery in one embodiment of the present invention during in-situ working condition observation;

[0024] Figure 2 It is a three-dimensional schematic diagram of an observation device for in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0025] Figure 3 A front view of an observation device for in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0026] Figure 4 A cross-sectional view of an observation device for an in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0027] Figure 5 An exploded view of an observation device for an in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0028] Figure 6 The first week charge and discharge curve of a lithium battery cross-section block installed in the observation device for the in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0029] Figure 7 A battery cycle life diagram of a lithium battery cross-section block installed in an observation device for an in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0030] Figure 8 An optical microscope image of a fully charged battery state in which a lithium battery cross-section block is installed in an observation device for the in-situ working condition reaction of a lithium battery in one embodiment of the present invention;

[0031] Fig. 9 This is an in-situ Raman result diagram of a battery charged to a specified capacity when a lithium battery cross-section block is installed in an observation device for in-situ operating reaction of a lithium battery in one embodiment of the present invention.

[0032] In the figure:

[0033] 1-outer shell; 2-observation cover; 21-transparent observation window; 22-upper part of observation cover; 23-lower part of observation cover; 31-lower base; 32-internal pole ear; 321-one end of internal pole ear; 322-other end of internal pole ear; 33-connecting piece; 34-upper base; 35-inner shell; 36-upper nut; 37-lower nut; 38-lower gasket; 4-external pole ear; 51-lifting nut; 52-lifting seat body; 61-upper sealing ring of observation cover; 62-lower sealing ring of observation cover; 63-first sealing ring of outer shell; 64-second sealing ring of outer shell; 7-lithium battery cross-section block; 81-high magnification microscope / (or) high magnification confocal Raman microscope; 82-optical imaging / (or) spectral test system; 83-battery test control system; 84-battery test equipment. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0035] like Figure 1-5 As shown, the present invention provides an observation device for the in-situ working condition reaction of a lithium battery. In one embodiment, the observation device for the in-situ working condition reaction of a lithium battery comprises an outer shell 1, an observation cover 2, a battery placement device, an external pole ear 4, and a lifting seat, wherein:

[0036] The outer shell 1 is hollow and has an outer shell opening at its upper part. The observation cover 2 is arranged on the outer shell opening. The observation cover 2 has a transparent observation window 21. Specifically, in one embodiment, the observation cover 2 includes an observation cover upper part 22, a transparent observation window 21 and an observation cover lower part 23. The transparent observation window 21 is arranged between the observation cover upper part 21 and the observation cover lower part 23. The material of the transparent observation window 21 can be specifically set to quartz.

[0037] The battery placement device includes: a lower base 31, an inner pole ear 32, a connecting member 33, an upper base 34, an inner shell 35, an upper nut 36, an upper gasket (not shown in the figure), a lower nut 37, and a lower gasket 38. The connecting member 33 is specifically a bolt in one embodiment. Two inner pole ears 32 are provided, and one end 321 of the inner pole ear and the other end 322 of the inner pole ear are respectively provided in the upper and lower directions. The inner pole ear 32 is specifically "L"-shaped, and one end 321 of the inner pole ear is bent inwardly and has a pole ear through hole (not shown in the figure). The other end 322 of the internal pole ear extends in the up-down direction. The two internal pole ears 33 are respectively used to communicate with the positive electrode and the negative electrode of the lithium battery cross-sectional block 7. A groove for embedding one end 321 of the internal pole ear is provided on the lower base 31. The lower base 31, the lower gasket 38, the one end 321 of the internal pole ear, the lower nut 37, the upper base 34, the upper gasket, the lithium battery cross-sectional block pole ear (not shown in the figure), and the upper nut 36 are arranged in sequence. In one embodiment, the connector 33 is connected to the lower The base 31, the lower gasket 38, the end 321 of the inner pole ear, the lower nut 37, the upper base 34, the upper gasket, the lithium battery cross-section block pole ear, and the upper nut 36. In other embodiments, it can also be configured that the connecting member 33 sequentially connects the lower base 31, the lower gasket 38, the end 321 of the inner pole ear, the lower nut 37, the upper base 34, the upper gasket, the upper nut 36, and the lithium battery cross-section block pole ear. In other embodiments, the upper gasket and / or the lower gasket 38 can be omitted. By setting the upper gasket and / or the lower gasket 38 , which can increase friction and prevent the connector 33 from loosening, so as to avoid the lithium battery cross-section block pole ear and the internal pole ear 32 from being unable to communicate. The upper base 34 is connected to the inner shell 35. Specifically, in one embodiment, the two can be connected by snapping. The inner shell 35 is hollow and is used to place the lithium battery cross-section block 7. The other end 322 of the internal pole ear is set on the outer side of the inner shell. Specifically, in one embodiment, the outer side of the inner shell 35 is slightly concave inward, and the other end 322 of the internal pole ear is embedded in the concave area to prevent displacement. The upper opening of the inner shell 35 is convenient for cooperating with the transparent observation window to observe the cross section of the lithium battery cross-section block 7.

[0038] A clearance hole is provided on the side of the outer shell 1, and the external connection tab 4 is passed through the clearance hole to contact and connect with the other end of the internal connection tab 32, so as to be connected with an external device.

[0039] The lifting seat includes a lifting nut 51 and a lifting seat body 52. ​​The lifting nut 51 is screwed under the lifting seat body 52. ​​The lifting seat body 52 is connected to the lower base 31. Specifically in one embodiment, the lifting seat body 52 and the lower base can be engaged through a protrusion. By screwing the lifting nut 51 in and out, it can be suitable for lithium battery cross-sectional blocks of different sizes, and the observation height of the lithium battery cross-sectional block 7 can also be adjusted.

[0040] In order to prevent external air from entering the observation device for the in-situ operating reaction of the lithium battery and also to prevent leakage of the battery electrolyte, the observation device for the in-situ operating reaction of the lithium battery of the present invention may further include a sealing ring. Specifically, in one embodiment, it includes an observation cover upper sealing ring 61, and the observation cover upper sealing ring 61 is arranged between the observation cover upper part 22 and the transparent observation window 21. In one embodiment, it also includes an observation cover lower sealing ring 62, and the observation cover lower sealing ring 62 is arranged between the observation cover lower part 23 and the transparent observation window 21. In one embodiment, it also includes an outer shell first sealing ring 63, and the outer shell first sealing ring 63 is arranged between the upper part of the outer shell 1 and the observation cover 2. In one embodiment, it also includes an outer shell second sealing ring 64, and there are two outer shell second sealing rings 64, which are respectively arranged between the side of the outer shell 1 and the external pole ear 4.

[0041] In one embodiment, in order to stably place the lithium battery cross-sectional block 7 in the inner shell 35, a fixing piece may be screwed into the inner shell, and the lithium battery cross-sectional block 7 is arranged inside the fixing piece.

[0042] In the inert atmosphere of the glove box, the lithium battery cross-section block 7 is injected with liquid and left to stand in vacuum for 60 minutes, so that the electrolyte fully penetrates into the positive and negative electrode plates and the diaphragm inside the lithium battery. After the lithium battery cross-section block 7 is installed in the observation device for the in-situ working condition reaction of the lithium battery of the present invention, Figure 1 As shown, the lithium battery in-situ working condition reaction observation device of the present invention is taken into the atmosphere, connected to the battery test control system 23 through the electrode connection line, and the battery is formed at a rate of 0.2C, with a cut-off voltage of 4.3V. Then other required charge and discharge tests are carried out.

[0043] The observation device for the in-situ working condition reaction of the lithium battery is taken into the atmospheric environment and placed directly under the objective lens of the high-magnification optical microscope system / (or) high-magnification confocal Raman microscope system to realize the in-situ morphology observation / in-situ Raman spectrum test of the cross-section battery during the in-situ charge and discharge process. The optical microscope system / (or) high-magnification confocal Raman microscope system includes a high-magnification microscope / high-magnification confocal Raman microscope 81 and a high-magnification microscope / high-magnification confocal Raman microscope control and optical imaging / (or) spectrum test system 82. In one embodiment, the first week charge and discharge curve of the lithium battery cross-section block is as follows: Figure 6 As shown by Figure 6 It can be seen that the coulombic efficiency of the lithium battery cross-section block in the first week of 3.0-4.45V charging and discharging range is 90.0%, which is consistent with the first week efficiency of the actual battery; this shows that the observation device for the in-situ working condition reaction of the lithium battery has good airtightness, and the lithium battery cross-section block can be charged and discharged normally in the first week. Furthermore, the long-term cycle life of the battery is as follows Figure 7 As shown by Figure 7It can be seen that the capacity retention rate of the lithium battery cross-section block is 90.7% after 500 weeks when the battery is charged and discharged slowly (0.5C charging, 0.5C rate discharging, N9); the capacity retention rate of the cross-section battery is 70.2% after 500 weeks when the battery is charged and discharged quickly (2C charging, 2C rate discharging, N11). Figure 7 The experimental results fully demonstrate that the observation device for the in-situ working condition reaction of the lithium battery of the present invention can realize the long-term stable cycle of the lithium battery cross-section block. In one embodiment, Figure 8 The figure shows the in-situ optical microscopic observation of the battery charge and discharge process in the first week, in which the positive electrode, negative electrode and separator of the battery can be clearly distinguished, and the charge and discharge state of the particles can be judged by the color change. In one embodiment, Fig. 9 As shown, the Raman image can be used to observe the crystal structure of lithium battery materials and different materials.

[0044] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A lithium battery in-situ operating reaction observation device, characterized in that: include: An outer shell, wherein the outer shell is hollow and has an outer shell opening at the top; An observation cover, which is arranged on the opening of the outer shell, and the observation cover has a transparent observation window; A battery placement device, comprising: a lower base, an inner pole ear, a connector, an upper base, and an inner shell, wherein the connector sequentially connects the lower base, one end of the inner pole ear, and the upper base, a pole ear of a lithium battery cross-section block can be arranged above the upper base and contact and connect with the connector, the upper base is connected to the inner shell, the inner shell is hollow and is used to place a lithium battery cross-section block, and the other end of the inner pole ear is arranged on the outer side of the inner shell; The external pole ear is provided with a clearance hole on the side of the outer shell, and the external pole ear is passed through the clearance hole to contact and connect with the other end of the internal pole ear.

2. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: It also includes an upper nut, which is arranged above the upper base and connected to the connecting piece, and the lithium battery cross-section block pole ear can be arranged between the upper nut and the upper base.

3. The observation device for in-situ working condition reaction of a lithium battery according to claim 2, characterized in that: It also includes an upper gasket, which is arranged above the upper base and in contact with the upper base, and the lithium battery cross-section block tab can be arranged between the upper gasket and the upper nut.

4. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: It also includes a lower nut, which is arranged below the lower base and connected to the connecting piece, and one end of the internally connected pole ear is arranged between the lower nut and the lower base.

5. The observation device for in-situ working condition reaction of a lithium battery according to claim 4, characterized in that: It also includes a lower gasket, which is arranged above the lower base and in contact with the lower base, and one end of the inner pole ear is arranged between the lower gasket and the lower nut.

6. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: One end of the internally connected pole lug is provided with a pole lug through hole, and the connecting member is passed through the pole lug through hole.

7. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: It also includes a lifting seat, which includes a lifting nut and a lifting seat body. The lifting nut is screwed under the lifting seat body, and the lifting seat body is connected to the lower base.

8. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: The observation cover comprises an observation cover upper part, a transparent observation window and an observation cover lower part, and the transparent observation window is arranged between the observation cover upper part and the observation cover lower part.

9. The observation device for in-situ working condition reaction of a lithium battery according to claim 8, characterized in that: It also includes an observation cover upper sealing ring, which is arranged between the upper part of the observation cover and the transparent observation window, and / or it also includes an observation cover lower sealing ring, which is arranged between the lower part of the observation cover and the transparent observation window.

10. The observation device for in-situ working condition reaction of a lithium battery according to claim 1, characterized in that: It also includes a first sealing ring of the outer shell, which is arranged between the upper part of the outer shell and the observation cover, and / or it also includes a second sealing ring of the outer shell, which is arranged between the side of the outer shell and the external pole ear.

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