Secondary battery, preparation method of secondary battery, energy storage system and electric equipment

Abstract

The invention relates to the technical field of energy storage, and discloses a secondary battery, a preparation method of the secondary battery, an energy storage system and electric equipment.The secondary battery comprises a shell, electrolyte and at least one battery cell assembly, the shell is provided with a containing space, and the containing space is used for containing the electrolyte and the at least one battery cell assembly; each battery cell assembly is at least partially immersed in the electrolyte; the battery cell assembly comprises a positive pole piece, a negative pole piece, a diaphragm and a first scintillator layer; the diaphragm is positioned between the positive pole piece and the negative pole piece; the negative pole piece comprises a negative current collector and a negative active material layer; the first scintillator layer is coated on one side, close to the negative pole piece, of the diaphragm, or the first scintillator layer is arranged between the negative current collector and the negative active material layer, or the first scintillator layer is coated on one side, close to the diaphragm, of the negative pole piece; the first scintillator layer generates a first optical signal under the irradiation of the radiation source. Therefore, the detection accuracy of the secondary battery is improved, and the safety of the secondary battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and particularly relates to a secondary battery, a preparation method of the secondary battery, an energy storage system, and an electrical device. Background Art

[0002] In the field of energy storage, the high energy density of energy storage batteries poses potential safety hazards. Traditional detection methods such as electrochemical tests, voltage monitoring, or electron microscopes are difficult to achieve non-destructive and dynamic monitoring of internal structure changes.

[0003] However, the current monitoring solutions for the interior of energy storage batteries still have problems with poor detection effects, leading to significant safety hazards for energy storage batteries. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a secondary battery, a preparation method of the secondary battery, an energy storage system, and an electrical device. By providing a first scintillator layer in the secondary battery, the accuracy of detecting the secondary battery is improved, and the safety of the secondary battery is enhanced.

[0005] To solve the above technical problems, an embodiment of the present application provides a secondary battery, including: a housing, an electrolyte, and at least one cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one cell assembly, and each cell assembly is at least partially immersed in the electrolyte; the cell assembly includes: a positive electrode plate, a negative electrode plate, a separator, and a first scintillator layer; the separator is located between the positive electrode plate and the negative electrode plate; the negative electrode plate includes a negative current collector and a negative active material layer; the first scintillator layer is coated on one side of the separator close to the negative electrode plate, or the first scintillator layer is disposed between the negative current collector and the negative active material layer, or the first scintillator layer is coated on one side of the negative electrode plate close to the separator; the first scintillator layer is configured to generate a first optical signal under the irradiation of a radiation source.

[0006] An embodiment of the present application further provides a preparation method of a secondary battery for preparing the above secondary battery. The preparation method of the secondary battery includes: after the secondary battery is filled with liquid and sealed, irradiating the secondary battery with the radiation source to enable the first scintillator layer to generate the first optical signal; collecting the first optical signal through an optical sensor and converting the first optical signal into a first digital image; extracting first internal structure information of the secondary battery from the first digital image; and determining whether the secondary battery is qualified according to the first internal structure information.

[0007] An embodiment of the present application further provides an energy storage system, including: a plurality of secondary batteries as described above.

[0008] Embodiments of the present application further provide an electrical device, including: the energy storage system as described above.

[0009] In some embodiments, the secondary battery further includes a second scintillator layer; the positive electrode plate includes a positive current collector and a positive active material layer; the second scintillator layer is coated on one side of the separator close to the positive electrode plate, or the second scintillator layer is disposed between the positive current collector and the positive active material layer, or the second scintillator layer is coated on one side of the positive electrode plate close to the separator; the second scintillator layer is configured to generate a second optical signal under the irradiation of the radiation source.

[0010] In some embodiments, a first protective film covers the first scintillator layer; when the first scintillator layer is disposed between the negative current collector and the negative active material layer, the negative active material layer covers the first protective film; a second protective film covers the second scintillator layer; when the second scintillator layer is disposed between the positive current collector and the positive active material layer, the positive active material layer covers the second protective film.

[0011] In some embodiments, when the first scintillator layer is coated on one side of the separator close to the negative electrode plate, the material of the first protective film is silicon carbide or aluminum oxide, and / or, the thickness of the first protective film is 2 μm to 5 μm; when the first scintillator layer is disposed between the negative current collector and the negative active material layer, the material of the first protective film is silicon carbide or aluminum oxide, and / or, the thickness of the first protective film is 2 μm to 5 μm; when the first scintillator layer is coated on one side of the negative electrode plate close to the separator, the material of the first protective film is silicon carbide or aluminum oxide, and / or, the thickness of the first protective film is 2 μm to 5 μm; when the second scintillator layer is coated on one side of the separator close to the positive electrode plate, the material of the second protective film is silicon carbide or aluminum oxide, and / or, the thickness of the second protective film is 2 μm to 5 μm; when the second scintillator layer is disposed between the positive current collector and the positive active material layer, the material of the second protective film is silicon carbide or aluminum oxide, and / or, the thickness of the second protective film is 2 μm to 5 μm; when the second scintillator layer is disposed on one side of the positive electrode plate close to the separator, the material of the second protective film is silicon carbide or aluminum oxide, and / or, the thickness of the second protective film is 2 μm to 5 μm.

[0012] In some embodiments, when the first scintillator layer is coated on one side of the separator close to the negative electrode plate, the thickness of the first scintillator layer is 3 μm to 8 μm; when the first scintillator layer is disposed between the negative current collector and the negative active material layer, the thickness of the first scintillator layer is 3 μm to 8 μm; when the first scintillator layer is coated on one side of the negative electrode plate close to the separator, the thickness of the first scintillator layer is 3 μm to 8 μm; when the second scintillator layer is coated on one side of the separator close to the positive electrode plate, the thickness of the second scintillator layer is 3 μm to 8 μm; when the second scintillator layer is disposed between the positive current collector and the positive active material layer, the thickness of the second scintillator layer is 3 μm to 8 μm; when the second scintillator layer is disposed on one side of the positive electrode plate close to the separator, the thickness of the second scintillator layer is 3 μm to 8 μm.

[0013] In some embodiments, the material of the first scintillator layer is different from that of the second scintillator layer; the material of the first scintillator layer is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS; the material of the second scintillator layer is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS.

[0014] The technical solution provided by the embodiments of the present application has at least the following advantages: In the embodiments of the present application, by providing a first scintillator layer in the secondary battery, when the secondary battery is irradiated by a radiation source, after the radiation passes through the housing and penetrates the internal structure of the secondary battery, it reaches the first scintillator layer, so that the first scintillator layer generates a first optical signal, and the first optical signal has the internal structure information of the secondary battery. The accurate internal structure information of the secondary battery can be obtained without damaging the secondary battery, improving the accuracy of the detection of the secondary battery and the safety of the secondary battery; moreover, the internal structure information of the secondary battery in the embodiments of the present application can be obtained only by irradiating with a radiation source, which also reduces the cost of detecting the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are illustrated by way of example in the accompanying drawings, which do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the figures do not constitute a scale limitation.

[0016] Figure 1 is a schematic structural diagram of a core component of a secondary battery according to an embodiment of the present application; Figure 2 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to an embodiment of the present application; Figure 3 It is a structural schematic diagram of a cell assembly of a secondary battery according to another embodiment of the present application; Figure 4 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to another embodiment of the present application; Figure 5 It is a structural schematic diagram of a cell assembly of a secondary battery according to still another embodiment of the present application; Figure 6 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to still another embodiment of the present application; Figure 7 It is a structural schematic diagram of a cell assembly of a secondary battery according to yet another embodiment of the present application; Figure 8 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to yet another embodiment of the present application; Figure 9 It is a structural schematic diagram of a cell assembly of a secondary battery according to another embodiment of the present application; Figure 10 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to another embodiment of the present application; Figure 11 It is a structural schematic diagram of a cell assembly of a secondary battery according to still another embodiment of the present application; Figure 12 It is a specific structural schematic diagram of a cell assembly of a secondary battery according to still another embodiment of the present application; Figure 13 It is a flow schematic diagram of a preparation method of a secondary battery according to an embodiment of the present application; Figure 14 It is a flow schematic diagram of another preparation method of a secondary battery according to an embodiment of the present application. Detailed Embodiments

[0017] As can be seen from the background art, the detection effect of the existing secondary battery is poor, resulting in a large potential safety hazard for the secondary battery.

[0018] Through analysis and research, it is found that: the high energy density of the secondary battery poses a large potential safety hazard for the secondary battery, such as problems like lithium dendrite growth leading to short circuits and thermal runaway. Traditional detection means such as electrochemical tests and voltage monitoring are difficult to achieve the function of non-destructively and dynamically monitoring the internal structure changes of the secondary battery. Therefore, at present, there are some non-destructive monitoring methods for secondary batteries, such as microscopic imaging technology, in-situ monitoring technology, and spectroscopy and gas analysis technology.

[0019] Microscopic imaging techniques include electron microscopy imaging and cryo-electron microscopy imaging. Electron microscopy imaging obtains high-resolution (sub-micron to nano-scale) dendritic morphology images by scanning or penetrating the sample with a high-energy electron beam. Cryo-electron microscopy imaging directly observes the true morphology of lithium dendrites and the SEI (Solid Electrolyte Interphase) layer by cryo-freezing and fixing the internal structure of the battery to avoid electron beam damage.

[0020] In-situ monitoring techniques include in-situ electrochemical atomic force microscopy, intelligent separator detection, and voltage signal analysis method. In-situ electrochemical atomic force microscopy (Atomic Force Microscopy, AFM) combines electrochemical control and AFM imaging to real-time observe the dynamic growth process of dendrites on the electrode surface, but requires a flat sample and is difficult to penetrate the electrolyte. Intelligent separator detection loads magnetic metal compounds on the separator surface and indirectly monitors dendrite growth through magnetic field changes, without the need to disassemble the battery and with real-time performance, but the sensitivity and positioning accuracy are limited. The voltage signal analysis method monitors the change of the negative electrode potential through a three-electrode system and correlates the terminal voltage fluctuation to judge lithium deposition and dendrite formation, which is suitable for online monitoring but depends on the accuracy of the model.

[0021] Spectral and gas analysis techniques include stimulated Raman scattering and hydrogen capture method. Stimulated Raman scattering identifies dendrites based on the vibration characteristics of chemical bonds, which is non-destructive but the equipment is complex and the cost is high. The hydrogen capture method indirectly reflects dendrite growth by detecting the hydrogen production of the battery and can achieve in-situ monitoring but requires special devices.

[0022] It can be seen that the above-mentioned related technologies still have the technical problem of poor detection accuracy of secondary batteries, resulting in great safety hazards for secondary batteries, and there is also a problem of high detection cost for secondary batteries at present.

[0023] To solve the above technical problems, an embodiment of the present application provides a secondary battery, including: a housing, an electrolyte, and at least one cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one cell assembly, and each cell assembly is at least partially immersed in the electrolyte. The cell assembly includes: a positive electrode plate, a negative electrode plate, a separator, and a first scintillator layer. The separator is located between the positive electrode plate and the negative electrode plate. The negative electrode plate includes a negative current collector and a negative active material layer. The first scintillator layer is coated on one side of the separator close to the negative electrode plate, or the first scintillator layer is disposed between the negative current collector and the negative active material layer, or the first scintillator layer is coated on one side of the negative electrode plate close to the separator. The first scintillator layer is configured to generate a first optical signal under the irradiation of a radiation source.

[0024] In an embodiment of the present application, by providing a first scintillator layer in the secondary battery, when the secondary battery is irradiated by a radiation source, after the radiation passes through the housing and penetrates the internal structure of the secondary battery, it reaches the first scintillator layer, causing the first scintillator layer to generate a first optical signal. This first optical signal has the internal structure information of the secondary battery, enabling accurate internal structure information of the secondary battery to be obtained without damaging the secondary battery, improving the accuracy of the detection of the secondary battery and enhancing the safety of the secondary battery. Moreover, the internal structure information of the secondary battery in the embodiment of the present application can be obtained only by irradiating with a radiation source, which also reduces the cost of detecting the secondary battery.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will elaborate on each embodiment of the present application with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of the present application, many technical details are provided to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented. The following division of each embodiment is for convenience of description and should not constitute any limitation on the specific implementation manner of the present application. Each embodiment can be combined and cross-referenced with each other on the premise of no contradiction.

[0026] An embodiment of the present application relates to a secondary battery. The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0027] Refer to Figure 1 , which is a schematic structural diagram of the battery cell assembly of the secondary battery according to an embodiment of the present application. Figure 1 Only a partially simplified positive electrode tab 10, negative electrode tab 20, and separator 30 of the battery cell assembly of the secondary battery are shown, facilitating the understanding of the solution.

[0028] The battery cell assembly includes: a positive electrode tab 10, a negative electrode tab 20, a separator 30, and a first scintillator layer 40; the separator 30 is located between the positive electrode tab 10 and the negative electrode tab 20; the first scintillator layer 40 is coated on the side of the separator 30 close to the negative electrode tab 20; the first scintillator layer 40 is configured to generate a first optical signal under the irradiation of a radiation source.

[0029] In practical applications, during the process of detecting the internal structure of a secondary battery, the secondary battery is irradiated by a radiation source, such as an X-ray source. After the first scintillator layer 40 receives the X-rays, the first scintillator layer 40 responds and generates a first optical signal. The first optical signal is collected by an optical sensor, and the optical sensor converts the first optical signal into a first digital image. The first digital image contains image information of all the internal structures of the secondary battery, including the image information of the positive electrode plate 10, the negative electrode plate 20, and the separator 30. Since the closer the structure is to the first scintillator layer 40, the more complete the information captured by the first scintillator layer 40 is. Therefore, in this embodiment, the first scintillator layer 40 is disposed close to the negative electrode plate 20 and the separator 30, so that the internal structure of the accurate negative electrode plate 20 and the internal structure of the separator 30 can be obtained. After that, in order to obtain the internal structure of the accurate negative electrode plate 20 and the internal structure of the separator 30, the first internal structure information of the secondary battery is extracted from the first digital image. The first internal structure information can be the internal structure information of the negative electrode plate 20 and the internal structure information of the separator 30. The internal structure information of the negative electrode plate 20 includes the growth condition of lithium dendrites, and the internal structure information of the separator 30 includes the deformation condition of the separator 30.

[0030] In this embodiment, the thickness of the first scintillator layer 40 is 3 μm to 8 μm. For example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm.

[0031] Since the microporous structure in the separator 30 allows ions (including lithium ions or other ions) in the electrolyte to pass through, thereby realizing ion conduction during the charge and discharge process of the secondary battery, and the ion conduction performance of the separator 30 directly affects the charge and discharge efficiency and rate performance of the secondary battery. Therefore, in this embodiment, by setting the thickness of the first scintillator layer 40 within this range, on the one hand, it can be avoided that the relatively thick thickness of the first scintillator layer 40 affects the ion conductivity of the separator 30 itself, ensuring that the separator 30 has good ion conductivity and ensuring that the secondary battery has good charge and discharge efficiency and rate performance. On the other hand, it can be avoided that the relatively thin first scintillator layer 40 results in a weak first optical signal being obtained, and the accurate internal information of the secondary battery cannot be captured, thereby improving the accuracy of secondary battery detection and the safety of the secondary battery. In order to further balance the ion conduction of the separator 30 and the accuracy of secondary battery detection, the thickness of the first scintillator layer 40 can be further set to 4 μm to 6 μm. For example: 4 μm, 5 μm, 6 μm.

[0032] In some embodiments, a first protective film is covered on the first scintillator layer 40.

[0033] Reference Figure 2 , is a schematic diagram of the specific structure of the core component of the secondary battery of this embodiment. Figure 2Only a partially simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the cell assembly of the secondary battery are shown schematically for easy understanding of the solution.

[0034] In the secondary battery of this embodiment, the first scintillator layer 40 is coated on one side of the separator 30 close to the negative electrode plate 20, the first protective film 50 covers the surface of the first scintillator layer 40 away from the separator 30, and the negative electrode plate 20 covers the first protective film 50.

[0035] In this embodiment, by covering the first scintillator layer 40 with the first protective film 50, the setting of the first protective film 50 can not only enhance the mechanical stability of the separator 30, so as to improve the imaging contrast of low atomic number (such as lithium element) when the secondary battery is irradiated by a radiation source, but also prevent the first scintillator layer 40 from reacting with the electrolyte, improve the stability of the first scintillator layer 40, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0036] In some embodiments, the first protective film 50 is deposited on the first scintillator layer 40 by atomic layer deposition (ALD). Atomic layer deposition can form a nanoscale first protective film 50 on the first scintillator layer 40, and the thickness of the first protective film 50 is uniform and has good compactness, improving the corrosion resistance of the first protective film 50 and the stability of the first scintillator layer 40.

[0037] In some embodiments, the thickness of the first protective film 50 is less than the thickness of the first scintillator layer 40.

[0038] In this embodiment, by setting the thickness of the first protective film 50 to be less than the thickness of the first scintillator layer 40, on the one hand, the first protective film 50 can protect the first scintillator layer 40 and prevent the first scintillator layer 40 from reacting with the electrolyte, improving the stability of the first scintillator layer 40; on the other hand, when the secondary battery is irradiated by a radiation source, the closer the structure is to the first scintillator layer 40, the more accurate the first scintillator layer 40 captures the information of the structure. When detecting the secondary battery, the main purpose of setting the first scintillator layer 40 is to obtain the internal structure information of the negative electrode plate 20 to monitor the dendrite growth at the negative electrode plate 20. Therefore, in this embodiment, the thickness of the first protective film 50 is set to be relatively thin, so that the first scintillator layer 40 is closer to the negative electrode plate 20. Thus, when the secondary battery is irradiated by a radiation source, the first scintillator layer 40 can obtain accurate internal structure information of the negative electrode plate 20, improving the accuracy of secondary battery detection and thus the safety of the secondary battery. In addition, the problem that the thickness of the first protective film 50 is too thick affects the ion conductivity of the separator 30 is also avoided, ensuring that the separator 30 has good ion conductivity.

[0039] In some embodiments, to ensure that the separator 30 has good ionic conductivity, the porosity of the separator 30 is greater than or equal to 40%, ensuring that lithium ions or other ions can be normally transmitted and improving the ionic conductivity of the separator 30.

[0040] The thickness of the first protective film 50 in this embodiment is 2 μm to 5 μm, such as 2 μm, 3 μm, 4 μm, 5 μm. By setting the thickness of the first protective film 50 within this range, on the one hand, it can avoid the problem that the first protective film 50 is too thin to prevent the first scintillator layer 40 from reacting with the electrolyte, and can prevent the first scintillator layer 40 from reacting with the electrolyte, improving the stability of the first scintillator layer 40; on the other hand, it also avoids the problem that the first protective film 50 is too thick and the resolution of the first digital image obtained when the secondary battery is irradiated by the radiation source is poor, thereby improving the accuracy of secondary battery detection and the safety of the secondary battery; at the same time, it can also ensure that the thickness of the first protective film 50 does not affect the ionic conductivity of the separator 30, making the separator 30 have good ionic conductivity.

[0041] In some embodiments, the material of the first protective film 50 is silicon carbide or alumina.

[0042] Since silicon carbide or alumina has strong anti-electrolyte corrosion ability, while isolating the first scintillator layer 40 from the electrolyte, it also avoids the first protective film 50 from being corroded by the electrolyte, improving the stability of the first scintillator layer 40, the accuracy of secondary battery detection, and thus the safety of the secondary battery.

[0043] In some embodiments, the material of the first scintillator layer 40 is any one of the following: Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS.

[0044] Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS are all submicron-level materials. During the detection of the secondary battery, submicron-level detection of the internal structure of the secondary battery can be achieved. After the first optical signal is converted into the first digital image by the optical sensor, the resolution of the converted first digital image is relatively high and can reach the submicron level.

[0045] In the related art, there is a solution to detect the internal structure of a secondary battery by disposing a scintillator layer outside the secondary battery. When performing detection, the secondary battery is placed between a radiation source and the scintillator layer. Thus, after the radiation source irradiates the secondary battery, imaging is performed through the scintillator layer. However, this solution is lower than the solution of the present application that disposes the scintillator layer inside the secondary battery in terms of spatial resolution, detection sensitivity, and dynamic response speed.

[0046] Referring to Table 1, it is a comparison table of the effects of disposing the scintillator layer outside the secondary battery in the related art and disposing the scintillator layer inside the secondary battery in this embodiment.

[0047] Table 1

[0048] It can be seen that compared with the related art, in this embodiment, the spatial resolution, detection sensitivity, and dynamic response speed have all been greatly improved. The spatial resolution has been improved from the micron level to the sub-micron level, the detection sensitivity for light elements has been enhanced, and the dynamic response speed has been improved from the millisecond level to the microsecond level.

[0049] Another embodiment of the present application relates to a secondary battery. The difference between this embodiment and the previous embodiment is that the first scintillator layer of this embodiment is disposed between the negative electrode current collector and the negative electrode active material layer.

[0050] The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0051] Refer to Figure 3 , which is a schematic structural diagram of the battery cell assembly of the secondary battery according to another embodiment of the present application. Figure 3 Only the partially simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the battery cell assembly of the secondary battery are schematically shown for easy understanding of the solution.

[0052] The battery cell assembly of this embodiment includes: a positive electrode plate 10, a negative electrode plate 20, a separator 30, and a first scintillator layer 40; the separator 30 is located between the positive electrode plate 10 and the negative electrode plate 20; the negative electrode plate 20 includes a negative electrode current collector 21 and a negative electrode active material layer 22; the first scintillator layer 40 is disposed between the negative electrode current collector 21 and the negative electrode active material layer 22; the first scintillator layer 40 is configured to generate a first optical signal under the irradiation of a radiation source.

[0053] In this embodiment, the thickness of the first scintillator layer 40 is from 3 μm to 8 μm, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm. Since the first scintillator layer 40 of this embodiment is disposed between the negative current collector 21 and the negative active material layer 22 of the negative electrode plate 20, the thickness of the first scintillator layer 40 will affect the thickness of the negative electrode plate 20, and the thickness of the negative electrode plate 20 will affect the performance of the secondary battery. Because although an increase in the thickness of the negative electrode plate 20 can improve the energy density, it will simultaneously bring problems of mechanical instability and sluggish electron-ion transport kinetics, resulting in a decrease in the rate performance and capacity retention rate of the secondary battery.

[0054] Therefore, in this embodiment, by setting the thickness of the first scintillator layer 40 within this range, on the one hand, it is possible to avoid the problem that a relatively thick first scintillator layer 40 affects the thickness of the negative electrode plate 20, resulting in a decrease in the rate performance and capacity retention rate of the secondary battery, and improve the performance of the secondary battery; on the other hand, it is possible to avoid the problem that a relatively thin first scintillator layer 40 results in a weak first optical signal being obtained and the accurate internal information of the secondary battery cannot be captured, improve the accuracy of secondary battery detection, and improve the safety of the secondary battery.

[0055] Since the first scintillator layer 40 of this embodiment is disposed between the negative current collector 21 and the negative active material layer 22 of the negative electrode plate 20, the thickness of the negative electrode plate 20 will affect the rate performance and capacity retention rate of the secondary battery. Therefore, in order to ensure that the secondary battery has good rate performance and capacity retention rate, the first scintillator layer 40 of this embodiment can be set to be relatively thinner than the previous embodiment, and the thickness of the first scintillator layer 40 can be further set within the range of 3 μm to 5 μm, for example, 3 μm, 4 μm, 5 μm. Thus, when setting the first scintillator layer 40, the thickness of the negative electrode plate 20 can be reduced as much as possible, the rate performance and capacity retention rate of the secondary battery can be improved, and the performance of the secondary battery can be improved.

[0056] Since the negative electrode plate 20 will undergo a large volume change during charge and discharge, even if the first scintillator layer 40 is disposed between the negative current collector 21 and the negative active material layer 22, the first scintillator layer 40 can adapt to this volume change. At the same time, the first scintillator layer 40 can also be protected from the mechanical stress of the electrode material, improving the stability of the first scintillator layer 40. In addition, the interface between the negative current collector 21 and the negative active material layer 22 is a key factor in battery performance. By disposing the first scintillator layer 40 between the negative current collector 21 and the negative active material layer 22, a buffer layer between the negative current collector 21 and the negative active material layer 22 can be formed, reducing the interfacial stress between the negative current collector 21 and the negative active material layer 22, and improving the interfacial stability.

[0057] In some embodiments, a first protective film 50 is covered on the first scintillator layer 40; refer to Figure 4 , which is a schematic structural diagram of the core component of the secondary battery in this embodiment, Figure 4 only the partial simplified positive electrode plate 10, negative electrode plate 20 and separator 30 of the core component of the secondary battery are shown, which is convenient for understanding the solution.

[0058] In the secondary battery of this embodiment, the first scintillator layer 40 is coated on one side of the negative electrode current collector 21 close to the negative electrode active material layer 22, the first protective film 50 covers the surface of the first scintillator layer 40 away from the negative electrode current collector 21, the negative electrode active material layer 22 covers the first protective film 50, and the separator 30 covers the negative electrode active material layer 22.

[0059] In this embodiment, by covering the first protective film 50 on the first scintillator layer 40, the setting of the first protective film 50 can not only enhance the mechanical stability of the negative electrode plate 20, so as to improve the imaging contrast of low atomic number (lithium element) when the secondary battery is irradiated by a radiation source, but also prevent the first scintillator layer 40 from reacting with the electrolyte, improve the stability of the first scintillator layer 40, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0060] In some embodiments, the thickness of the first protective film 50 is less than the thickness of the first scintillator layer 40, and the thickness of the first protective film 50 is 2 μm to 5 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm. Through this setting, on the one hand, the thickness of the first protective film 50 can achieve the protection effect on the first scintillator layer 40, prevent the first scintillator layer 40 from reacting with the electrolyte, and improve the stability of the first scintillator layer 40. On the other hand, the thickness of the first protective film 50 is set relatively thin, so that the overall thickness of the negative electrode plate 20 increases less, ensuring that the secondary battery has good rate performance and capacity retention rate, and improving the performance of the secondary battery.

[0061] In some embodiments, the material of the first protective film 50 is silicon carbide or alumina. Silicon carbide or alumina has strong anti-electrolyte corrosion ability. While isolating the first scintillator layer 40 from the electrolyte, it also prevents the first protective film 50 from being corroded by the electrolyte, improves the stability of the secondary battery, improves the accuracy of secondary battery detection, and thus improves the safety of the secondary battery.

[0062] In some embodiments, the material of the first scintillator layer 40 is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS. Gd2O2S:Eu 3+, Lu6O5F8:15Tb, and CsI:Tl-PDMS are all sub-micron materials. During the detection of secondary batteries, sub-micron detection of the internal structure of secondary batteries can be achieved. After the first optical signal is converted into a first digital image by an optical sensor, the resolution of the converted first digital image is relatively high and can reach the sub-micron level.

[0063] Another embodiment of the present application relates to a secondary battery. The difference between this embodiment and the previous embodiment is that the first scintillator layer of this embodiment is coated on the side of the negative electrode plate close to the separator.

[0064] The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0065] Reference Figure 5 , is a schematic structural diagram of the battery cell assembly of the secondary battery in another embodiment of the present application. Figure 5 Only a partial simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the battery cell assembly of the secondary battery are shown for easy understanding of the solution.

[0066] The battery cell assembly of this embodiment includes: a positive electrode plate 10, a negative electrode plate 20, a separator 30, and a first scintillator layer 40; the separator 30 is located between the positive electrode plate 10 and the negative electrode plate 20; the first scintillator layer 40 is coated on the side of the negative electrode plate 20 close to the separator 30; the first scintillator layer 40 is configured to generate a first optical signal under the irradiation of a radiation source.

[0067] Specifically, the negative electrode plate 20 includes a negative current collector and a negative active material layer; the negative active material layer is closer to the separator 30 than the negative current collector, and the first scintillator layer 40 is coated on the side of the negative active material layer close to the separator 30.

[0068] In this embodiment, the thickness of the first scintillator layer 40 is 3 μm to 8 μm, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm. Since the first scintillator layer 40 of this embodiment is provided on the side of the negative electrode plate 20 close to the separator 30, the thickness of the first scintillator layer 40 will affect the thickness of the negative electrode plate 20, and the thickness of the negative electrode plate 20 will affect the performance of the secondary battery. Because although an increase in the thickness of the negative electrode plate 20 can improve the energy density, it will also bring problems such as mechanical instability and sluggish electron-ion transport kinetics, resulting in a decrease in the rate performance and capacity retention rate of the secondary battery.

[0069] Therefore, in this embodiment, by setting the thickness of the first scintillator layer 40 within this range, on the one hand, it is possible to avoid the problem that a relatively thick thickness of the first scintillator layer 40 affects the thickness of the negative electrode plate 20, resulting in a decline in the rate performance and capacity retention rate of the secondary battery, and improve the performance of the secondary battery; on the other hand, it is possible to avoid the problem that a relatively thin first scintillator layer 40 results in a weak first optical signal obtained and an inability to capture accurate internal information of the secondary battery, improve the accuracy of secondary battery detection, and improve the safety of the secondary battery.

[0070] Since the first scintillator layer 40 of this embodiment is coated on the side of the negative electrode plate 20 close to the separator 30, the thickness of the negative electrode plate 20 will affect the rate performance and capacity retention rate of the secondary battery. Therefore, in order to ensure that the secondary battery has good rate performance and capacity retention rate, the first scintillator layer 40 of this embodiment can be set relatively thinner compared to the previous embodiment. The thickness of the first scintillator layer 40 of this embodiment can be further set within the range of 3 μm to 5 μm, such as 3 μm, 4 μm, 5 μm, so as to reduce the thickness of the negative electrode plate 20 and improve the rate performance and capacity retention rate of the secondary battery.

[0071] In some embodiments, a first protective film 50 is covered on the first scintillator layer 40; refer to Figure 6 , which is a schematic diagram of the specific structure of the cell assembly of the secondary battery of this embodiment, Figure 6 only the partial simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the cell assembly of the secondary battery are shown, facilitating the understanding of the solution.

[0072] In the secondary battery of this embodiment, the first scintillator layer 40 is coated on the side of the negative electrode plate 20 close to the separator 30, the first protective film 50 covers the surface of the first scintillator layer 40 away from the negative electrode plate 20, and the separator 30 covers the first protective film 50.

[0073] In this embodiment, by covering the first scintillator layer 40 with the first protective film 50, the setting of the first protective film 50 can not only enhance the mechanical stability of the negative electrode plate 20, thereby improving the imaging contrast of low atomic number (lithium element) when the secondary battery is irradiated by a radiation source, but also prevent the first scintillator layer 40 from reacting with the electrolyte, improve the stability of the first scintillator layer 40, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0074] In some embodiments, the thickness of the first protective film 50 is less than that of the first scintillator layer 40. The thickness of the first protective film 50 is 2 μm to 5 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm. With this arrangement, on the one hand, the thickness of the first protective film 50 can protect the first scintillator layer 40, preventing the first scintillator layer 40 from reacting with the electrolyte and improving the stability of the first scintillator layer 40. On the other hand, the thickness of the first protective film 50 is set relatively thin, so that the overall thickness of the negative electrode plate 20 increases less, ensuring that the secondary battery has good rate performance and capacity retention rate, and improving the performance of the secondary battery.

[0075] In some embodiments, the material of the first protective film 50 is silicon carbide or aluminum oxide. Silicon carbide or aluminum oxide has strong resistance to electrolyte corrosion. While isolating the first scintillator layer 40 from the electrolyte, it also prevents the first protective film 50 from being corroded by the electrolyte, improves the stability of the secondary battery, improves the accuracy of secondary battery detection, and thus improves the safety of the secondary battery.

[0076] In some embodiments, the material of the first scintillator layer 40 is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS. Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS are all sub-micron materials. During the detection of the secondary battery, sub-micron detection of the internal structure of the secondary battery can be achieved. After the first optical signal is converted into a first digital image by the optical sensor, the resolution of the converted first digital image is relatively high and can reach the sub-micron level.

[0077] Another embodiment of the present application relates to a secondary battery. The difference between this embodiment and the previous embodiment is that the secondary battery further includes a second scintillator layer.

[0078] The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0079] Refer to Figure 7 , which is a schematic structural diagram of the battery cell assembly of the secondary battery according to another embodiment of the present application. Figure 7 Only a partial simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the battery cell assembly of the secondary battery are shown, which is convenient for understanding the solution.

[0080] The battery cell assembly of this embodiment includes: a positive electrode tab 10, a negative electrode tab 20, a separator 30, a first scintillator layer 40, and a second scintillator layer 60; the separator 30 is located between the positive electrode tab 10 and the negative electrode tab 20; the first scintillator layer 40 is coated on the side of the negative electrode tab 20 close to the separator 30; the first scintillator layer 40 is configured to generate a first optical signal under the irradiation of a radiation source; the second scintillator layer 60 is coated on the side of the separator 30 close to the positive electrode tab 10; the second scintillator layer 60 is configured to generate a second optical signal under the irradiation of a radiation source.

[0081] It should be noted that Figure 7 in this embodiment, the first scintillator layer 40 is coated on the side of the negative electrode tab 20 close to the separator 30 for illustration, but the specific position of the first scintillator layer 40 is not limited. The first scintillator layer 40 can also be coated on the side of the separator 30 close to the negative electrode tab 20 (refer to Figure 1 , Figure 2 ), and the first scintillator layer 40 can also be disposed between the negative current collector 21 and the negative active material layer 22 (refer to Figure 3 , Figure 4 ). Moreover, the relevant technical details mentioned in the above embodiments are still valid in this embodiment. To avoid repetition, they will not be elaborated here.

[0082] In practical applications, during the process of detecting the internal structure of a secondary battery, the secondary battery is irradiated by a radiation source such as an X-ray source. After the first scintillator layer 40 receives the X-rays, the first scintillator layer 40 responds and generates a first optical signal. After the second scintillator layer 60 receives the X-rays, the second scintillator layer 60 responds and generates a second optical signal. The first optical signal and the second optical signal are collected by an optical sensor. The optical sensor converts the first optical signal into a first digital image and the second optical signal into a second digital image. The first digital image contains image information of all the internal structures of the secondary battery, including the image information of the positive electrode tab 10, the negative electrode tab 20, and the separator 30. The second digital image also contains image information of all the internal structures of the secondary battery, including the image information of the positive electrode tab 10, the negative electrode tab 20, and the separator 30.

[0083] Since the closer a structure is to the first scintillator layer 40, the more complete the information captured by the first scintillator layer 40, and the closer a structure is to the second scintillator layer 60, the more complete the information captured by the second scintillator layer 60; therefore, in this embodiment, the first scintillator layer 40 is disposed close to the negative electrode plate 20 and the separator 30, and the second scintillator layer 60 is disposed close to the positive electrode plate 10. The first digital image after the conversion of the first optical signal contains the internal structure of the precise negative electrode plate 20 and the internal structure information of the separator 30, and the second digital image after the conversion of the second optical signal contains the internal structure of the precise positive electrode plate 10 and the internal structure information of the separator 30; thereafter, the first internal structure information of the secondary battery is extracted from the first digital image. The first internal structure information may be the internal structure information of the negative electrode plate 20 and the internal structure information of the separator 30. The internal structure information of the negative electrode plate 20 includes the growth condition of lithium dendrites, and the internal structure information of the separator 30 includes the deformation condition of the separator 30; the second internal structure information of the secondary battery is extracted from the second digital image. The second internal structure information may be the internal structure information of the positive electrode plate 10, including the material cracks and interface peeling conditions of the positive electrode plate 10.

[0084] In this embodiment, the thickness of the second scintillator layer 60 is 3 μm to 8 μm; for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm. Since the microporous structure in the separator 30 allows ions (including lithium ions or other ions) in the electrolyte to pass through, thereby realizing the conduction of ions during the charge and discharge process of the secondary battery, and the ionic conductivity of the separator 30 directly affects the charge and discharge efficiency and rate performance of the secondary battery. Therefore, by setting the thickness of the second scintillator layer 60 within this range in this embodiment, on the one hand, it is possible to avoid the influence of the relatively thick thickness of the second scintillator layer 60 on the ionic conductivity of the separator 30 itself, ensure that the separator 30 has good ionic conductivity, and ensure that the secondary battery has good charge and discharge efficiency and rate performance; on the other hand, it is also possible to avoid the problem that the relatively thin second scintillator layer 60 results in a weak second optical signal obtained and the inability to capture the precise internal information of the secondary battery, thereby improving the accuracy of the secondary battery detection and the safety of the secondary battery.

[0085] Since the volume change of the positive electrode plate 10 is relatively small during the charge and discharge process, and its electrochemical reaction mainly occurs inside the positive electrode plate 10. Disposing the second scintillator layer 60 between the positive electrode plate 10 and the separator 30 can better monitor the interfacial reaction between the positive electrode plate 10 and the electrolyte 30, such as the processes of lithium ion diffusion and charge transfer at the interface. In addition, it can also protect the separator 30 from the side reactions of the positive electrode material.

[0086] In some embodiments, a second protective film 70 is covered on the second scintillator layer 60; such as Figure 8As shown, it is a specific structural schematic diagram of the battery cell assembly of the secondary battery in this embodiment. Figure 8 Only a partial simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the battery cell assembly of the secondary battery are shown, facilitating the understanding of the solution.

[0087] In the secondary battery of this embodiment, the second scintillator layer 60 is coated on one side of the separator 30 close to the positive electrode plate 10, the second protective film 70 covers the surface of the second scintillator layer 60 away from the separator 30, and the positive electrode plate 10 covers the second protective film 70.

[0088] In this embodiment, by covering the second scintillator layer 60 with the second protective film 70, the setting of the second protective film 70 can not only enhance the mechanical stability of the separator 30, thereby improving the imaging contrast of low atomic number elements (such as lithium) when the secondary battery is irradiated by a radiation source, but also prevent the second scintillator layer 60 from reacting with the electrolyte, improve the stability of the second scintillator layer 60, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0089] In some embodiments, the second protective film 70 is deposited on the second scintillator layer 60 by atomic layer deposition (ALD). Atomic layer deposition can form a nanoscale second protective film 70 on the second scintillator layer 60, and the second protective film 70 has a uniform thickness and good compactness, improving the corrosion resistance of the second protective film 70 and the stability of the second scintillator layer 60.

[0090] In some embodiments, the thickness of the second protective film 70 is less than the thickness of the second scintillator layer 60. By setting the thickness of the second protective film 70 to be less than the thickness of the second scintillator layer 60 in this embodiment, on the one hand, the second protective film 70 can protect the second scintillator layer 60 and prevent the second scintillator layer 60 from reacting with the electrolyte, improving the stability of the second scintillator layer 60; on the other hand, when the secondary battery is irradiated by a radiation source, the closer the structure is to the second scintillator layer 60, the more accurate the second scintillator layer 60 can obtain the information of the structure. When detecting the secondary battery, the main purpose of setting the second scintillator layer 60 is to obtain the internal structure information of the positive electrode plate 10 to monitor the material cracks and interface peeling at the positive electrode plate 10. Therefore, in this embodiment, the thickness of the second protective film 70 is set to be relatively thin, making the second scintillator layer 60 closer to the positive electrode plate 10. Thus, when the secondary battery is irradiated by a radiation source, the second scintillator layer 60 can obtain accurate internal structure information of the positive electrode plate 10, improving the accuracy of secondary battery detection and thus improving the safety of the secondary battery. In addition, the problem that the thick thickness of the second protective film 70 affects the ion conductivity of the separator 30 is also avoided, ensuring that the separator 30 has good ion conductivity.

[0091] In some embodiments, to ensure that the separator 30 has good ionic conductivity, the porosity of the separator 30 is greater than or equal to 40%, ensuring that lithium ions or other ions can be normally transmitted and improving the ionic conductivity of the separator 30.

[0092] The thickness of the second protective film 70 in this embodiment is 2 μm to 5 μm, such as 2 μm, 3 μm, 4 μm, 5 μm. By setting the thickness of the second protective film 70 within this range, on the one hand, it can avoid the problem that the second protective film 70 is too thin to prevent the second scintillator layer 60 from reacting with the electrolyte well, and can prevent the first scintillator layer 40 from reacting with the electrolyte, improving the stability of the second scintillator layer 60; on the other hand, it also avoids the problem that the second protective film 70 is too thick and the internal structure information of the positive electrode sheet 10 obtained when the secondary battery is irradiated by the radiation source is poor, thereby improving the accuracy of secondary battery detection, improving the safety of the secondary battery. At the same time, it can also ensure that the thickness of the second protective film 70 does not affect the ionic conductivity of the separator 30, making the separator 30 have good ionic conductivity.

[0093] In some embodiments, the material of the second protective film 70 is silicon carbide or alumina. Silicon carbide or alumina has strong anti-corrosion ability against the electrolyte. While isolating the second scintillator layer 60 from the electrolyte, it also avoids the second protective film 70 from being corroded by the electrolyte, improving the stability of the secondary battery, improving the accuracy of secondary battery detection, and thus improving the safety of the secondary battery.

[0094] In some embodiments, the material of the second scintillator layer 60 is any one of the following: Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS. Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS are all submicron-level materials. During the detection of the secondary battery, submicron-level detection of the internal structure of the secondary battery can be realized. After the second optical signal is converted into a second digital image by the optical sensor, the resolution of the converted second digital image is relatively high and can reach the submicron level.

[0095] In some embodiments, the material of the first scintillator layer 40 is different from that of the second scintillator layer 60. In this embodiment, by setting the materials of the first scintillator layer 40 and the second scintillator layer 60 to be different, the first scintillator layer 40 and the second scintillator layer 60 can generate optical signals in different wavelength bands when irradiated by the radiation source, so as to distinguish the first optical signal generated by the first scintillator layer 40 and the second optical signal generated by the second scintillator layer 60 according to the wavelength band, improving the accuracy of secondary battery detection.

[0096] For example, the material of the first scintillator layer 40 is set to Gd2O2S:Eu 3+ , after the secondary battery is irradiated with X-rays, Gd2O2S:Eu 3+ generates a first optical signal that is red light, and the wavelength is mainly concentrated at 610 nm; the material of the second scintillator layer 60 is CsI:Tl-PDMS. After the secondary battery is irradiated with X-rays, the second optical signal generated by CsI:Tl-PDMS is blue light, and the wavelength is mainly concentrated at 430 nm; the first optical signal and the second optical signal are distinguished according to the optical signals with different wavelengths generated by the first scintillator layer 40 and the second scintillator layer 60. Thus, the internal structure information of the negative electrode tab 20 and the internal structure information of the separator 30 can be obtained accurately according to the first digital image converted from the first optical signal, and the internal structure information of the positive electrode tab 10 can be obtained accurately according to the second digital image converted from the second optical signal, improving the accuracy of the secondary battery detection and the safety of the secondary battery.

[0097] Another embodiment of the present application relates to a secondary battery. The difference between this embodiment and the previous embodiment is that in the secondary battery of this embodiment, the positive electrode tab includes a positive current collector and a positive active material layer, and the second scintillator layer is disposed between the positive current collector and the positive active material layer.

[0098] The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has a receiving space for receiving the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0099] Reference Figure 9 , which is a schematic structural diagram of the battery cell assembly of the secondary battery according to another embodiment of the present application. Figure 9 Only a partially simplified positive electrode tab 10, negative electrode tab 20, and separator 30 of the battery cell assembly of the secondary battery are shown, facilitating the understanding of the solution.

[0100] The battery cell assembly of this embodiment includes: a positive electrode tab 10, a negative electrode tab 20, a separator 30, and a first scintillator layer 40; the separator 30 is located between the positive electrode tab 10 and the negative electrode tab 20; the first scintillator layer 40 is coated on the side of the negative electrode tab 20 close to the separator 30; the first scintillator layer 40 is configured to generate a first optical signal under the irradiation of a radiation source; the positive electrode tab 10 includes a positive current collector 11 and a positive active material layer 12, and a second scintillator layer 60 is disposed between the positive current collector 11 and the positive active material layer 12, and the second scintillator layer 60 is configured to generate a second optical signal under the irradiation of a radiation source.

[0101] It should be noted that Figure 9The description is made with the first scintillator layer 40 coated on the side of the negative electrode tab 20 close to the separator 30, but the specific position of the first scintillator layer 40 is not limited. The first scintillator layer 40 can also be coated on the side of the separator 30 close to the negative electrode tab 20 (refer to Figure 1 , Figure 2 ). The first scintillator layer 40 can also be disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 (refer to Figure 3 , Figure 4 ). Moreover, the relevant technical details mentioned in the above embodiments are still valid in this embodiment. To avoid repetition, they will not be elaborated here.

[0102] In this embodiment, the thickness of the second scintillator layer 60 is 3 μm to 8 μm; for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm.

[0103] Since the second scintillator layer 60 of this embodiment is disposed between the positive electrode current collector 11 and the positive electrode active material layer 12 of the positive electrode tab 10, the thickness of the second scintillator layer 60 will affect the thickness of the positive electrode tab 10, and the thickness of the positive electrode tab 10 will affect the performance of the secondary battery. Because although an increase in the thickness of the positive electrode tab 10 can improve the energy density, it will simultaneously reduce the rate performance, capacity retention rate, cycle life, and increase the internal resistance and self-discharge rate, resulting in a decline in the performance of the secondary battery.

[0104] Therefore, in this embodiment, by setting the thickness of the second scintillator layer 60 within this range, on the one hand, it is possible to avoid the problem that the relatively thick thickness of the second scintillator layer 60 affects the thickness of the positive electrode tab 10, resulting in a decline in the performance of the secondary battery, thereby improving the performance of the secondary battery; on the other hand, it is possible to avoid the problem that the relatively thin second scintillator layer 60 results in a weak second optical signal obtained and an inability to capture accurate internal information of the secondary battery, improving the accuracy of secondary battery detection and the safety of the secondary battery.

[0105] Since the second scintillator layer 60 of this embodiment is disposed between the positive electrode current collector of the positive electrode tab 10 and the positive electrode active material layer, the thickness of the positive electrode tab 10 will affect the performance of the secondary battery. Therefore, in order to ensure that the secondary battery has good performance, the second scintillator layer 60 of this embodiment can be set to be relatively thinner compared to the previous embodiment, and the thickness of the second scintillator layer 60 can be further set within the range of 3 μm to 5 μm, for example, 3 μm, 4 μm, 5 μm, so as to reduce the thickness of the positive electrode tab 10 and improve the performance of the secondary battery.

[0106] In some embodiments, a second protective film 70 is covered on the second scintillator layer 60; as Figure 10 shown, it is a schematic structural diagram of the cell assembly of the secondary battery of this embodiment, Figure 10Only a partially simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the cell assembly of the secondary battery are shown schematically for easy understanding of the solution.

[0107] In the secondary battery of this embodiment, the second scintillator layer 60 is coated on one side of the positive current collector 11 close to the positive active material layer 12, the second protective film 70 covers the surface of the second scintillator layer 60 away from the positive current collector 11, the positive active material layer 12 covers the second protective film 70, and the separator 30 covers the positive active material layer 12.

[0108] In this embodiment, by covering the second scintillator layer 60 with the second protective film 70, the setting of the second protective film 70 can not only enhance the mechanical stability of the positive electrode plate 10, so as to improve the imaging contrast of the obtained second digital image when the secondary battery is irradiated by a radiation source, but also prevent the second scintillator layer 60 from reacting with the electrolyte, improve the stability of the second scintillator layer 60, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0109] In some embodiments, the thickness of the second protective film 70 is less than the thickness of the second scintillator layer 60, and the thickness of the second protective film 70 is 2 μm to 5 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm. Through this setting, on the one hand, the thickness of the second protective film 70 can achieve the protection effect on the second scintillator layer 60, prevent the second scintillator layer 60 from reacting with the electrolyte, and improve the stability of the second scintillator layer 60. On the other hand, the thickness of the second protective film 70 is set relatively thin, so that the overall thickness of the positive electrode plate 10 increases less, ensuring that the secondary battery has better performance.

[0110] In some embodiments, the material of the second protective film 70 is silicon carbide or aluminum oxide. Silicon carbide or aluminum oxide has strong anti-electrolyte corrosion ability. While isolating the second scintillator layer 60 from the electrolyte, it also prevents the second protective film 70 from being corroded by the electrolyte, improves the stability of the secondary battery, improves the accuracy of secondary battery detection, and thus improves the safety of the secondary battery.

[0111] In some embodiments, the material of the second scintillator layer 60 is any one of the following: Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS. Gd2O2S:Eu 3+ 、Lu6O5F8:15Tb、CsI:Tl-PDMS are all submicron-level materials. During the detection of the secondary battery, submicron-level detection of the internal structure of the secondary battery can be achieved. After the second optical signal is converted into a second digital image by the optical sensor, the resolution of the converted second digital image is relatively high and can reach the submicron level.

[0112] In some embodiments, the material of the first scintillator layer 40 is different from that of the second scintillator layer 60. By setting the materials of the first scintillator layer 40 and the second scintillator layer 60 to be different in this embodiment, light signals of different wavelength bands can be generated when irradiated by a radiation source, so as to distinguish the first light signal generated by the first scintillator layer 40 and the second light signal generated by the second scintillator layer 60, thereby improving the detection accuracy.

[0113] Another embodiment of the present application relates to a secondary battery. The difference between this embodiment and the previous embodiment is that the second scintillator layer is coated on the side of the positive electrode plate close to the separator.

[0114] The secondary battery of this embodiment includes: a housing, an electrolyte, and at least one battery cell assembly. The housing has an accommodation space for accommodating the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte.

[0115] Reference Figure 11 , is a schematic structural diagram of the battery cell assembly of the secondary battery according to another embodiment of the present application. Figure 11 Only a partially simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the battery cell assembly of the secondary battery are shown, which is convenient for understanding the solution.

[0116] The battery cell assembly of this embodiment includes: a positive electrode plate 10, a negative electrode plate 20, a separator 30, and a first scintillator layer 40; the separator 30 is located between the positive electrode plate 10 and the negative electrode plate 20; the first scintillator layer 40 is coated on the side of the negative electrode plate 20 close to the separator 30; the first scintillator layer 40 is configured to generate a first light signal under the irradiation of a radiation source; the second scintillator layer 60 is coated on the side of the positive electrode plate 10 close to the separator 30, and the second scintillator layer 60 is configured to generate a second light signal under the irradiation of a radiation source.

[0117] It should be noted that Figure 11 the description is made with the first scintillator layer 40 coated on the side of the negative electrode plate 20 close to the separator 30, but the specific position of the first scintillator layer 40 is not limited. The first scintillator layer 40 can also be coated on the side of the separator 30 close to the negative electrode plate 20 (reference Figure 1 ), and the first scintillator layer 40 can also be disposed between the negative current collector 21 and the negative active material layer 22 (reference Figure 3 ). Moreover, the relevant technical details mentioned in the above embodiments are still valid in this embodiment. To avoid repetition, they will not be elaborated here.

[0118] In this embodiment, the thickness of the second scintillator layer 60 is from 3 μm to 8 μm; for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm. Since the second scintillator layer 60 of this embodiment is disposed on the side of the positive electrode plate 10 close to the separator 30, the thickness of the second scintillator layer 60 affects the thickness of the positive electrode plate 10, and the thickness of the positive electrode plate 10 affects the performance of the secondary battery. Because although an increase in the thickness of the positive electrode plate 10 can improve the energy density, it will simultaneously reduce the rate performance, capacity retention rate, cycle life, and increase the internal resistance and self-discharge rate, resulting in a decline in the performance of the secondary battery.

[0119] Therefore, in this embodiment, by setting the thickness of the second scintillator layer 60 within this range, on the one hand, it is possible to avoid the problem that the thickness of the second scintillator layer 60 being too thick affects the thickness of the negative electrode plate 20, resulting in a decline in the performance of the secondary battery, thereby improving the performance of the secondary battery; on the other hand, it is possible to avoid the problem that the second scintillator layer 60 being too thin results in a weak second optical signal obtained, and the accurate internal information of the secondary battery cannot be captured, improving the accuracy of the secondary battery detection and the safety of the secondary battery.

[0120] Since the second scintillator layer 60 of this embodiment is coated on the side of the positive electrode plate 10 close to the separator 30, the thickness of the positive electrode plate 10 affects the performance of the secondary battery. Therefore, in order to ensure that the secondary battery has good performance, the second scintillator layer 60 of this embodiment can be set relatively thinner compared to the previous embodiment, and the thickness of the second scintillator layer 60 of this embodiment can be further set within the range of 3 μm to 5 μm, for example, 3 μm, 4 μm, 5 μm, so as to reduce the thickness of the positive electrode plate 10 and improve the performance of the secondary battery.

[0121] In some embodiments, a second protective film covers the second scintillator layer 60; as Figure 12 shown, it is a schematic structural diagram of the cell assembly of the secondary battery of this embodiment, Figure 12 only showing a partially simplified positive electrode plate 10, negative electrode plate 20, and separator 30 of the cell assembly of the secondary battery, facilitating the understanding of the solution.

[0122] In the secondary battery of this embodiment, the second scintillator layer 60 is coated on the side of the positive electrode plate 10 close to the separator 30, that is, on the positive active material layer of the positive electrode plate 10, and the second protective film 70 covers the surface of the second scintillator layer 60 away from the positive electrode plate 10, and the separator 30 covers the second protective film 70.

[0123] In this embodiment, a second protective film 70 is covered on the second scintillator layer 60. The setting of the second protective film 70 can not only enhance the mechanical stability of the positive electrode plate 10, thereby improving the imaging contrast of the obtained second digital image when the secondary battery is irradiated by a radiation source, but also prevent the second scintillator layer 60 from reacting with the electrolyte, improve the stability of the second scintillator layer 60, improve the accuracy of secondary battery detection, and thus improve the safety of the secondary battery.

[0124] In some embodiments, the thickness of the second protective film 70 is less than the thickness of the second scintillator layer 60, and the thickness of the second protective film 70 is 2 μm to 5 μm. For example, 2 μm, 3 μm, 4 μm, 5 μm. With this setting, on the one hand, the thickness of the second protective film 70 can achieve the protection effect on the second scintillator layer 60, prevent the second scintillator layer 60 from reacting with the electrolyte, and improve the stability of the second scintillator layer 60. On the other hand, the thickness of the second protective film 70 is set to be relatively thin, so that the overall thickness of the positive electrode plate 10 increases less, ensuring that the secondary battery has better performance.

[0125] In some embodiments, the material of the second protective film 70 is silicon carbide or alumina. Silicon carbide or alumina has strong anti-electrolyte corrosion ability. While isolating the second scintillator layer 60 from the electrolyte, it also prevents the second protective film 70 from being corroded by the electrolyte, improves the stability of the secondary battery, improves the accuracy of secondary battery detection, and thus improves the safety of the secondary battery.

[0126] In some embodiments, the material of the second scintillator layer 60 is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS. Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS are all sub-micron materials. During the detection of the secondary battery, sub-micron detection of the internal structure of the secondary battery can be achieved. After the second optical signal is converted into a second digital image by the optical sensor, the resolution of the converted second digital image is relatively high and can reach the sub-micron level.

[0127] In some embodiments, the material of the first scintillator layer 40 is different from the material of the second scintillator layer 60. In this embodiment, by setting the material of the first scintillator layer 40 to be different from the material of the second scintillator layer 60, optical signals of different wavelength bands can be generated when irradiated by a radiation source, so as to distinguish the first optical signal generated by the first scintillator layer 40 and the second optical signal generated by the second scintillator layer 60, and improve the accuracy of detection.

[0128] One embodiment of the present application further relates to a method for manufacturing a secondary battery, which is used to manufacture the secondary battery of the above embodiment. Refer to Figure 13 , which is a schematic flow chart of the method for manufacturing the secondary battery of this embodiment. The method for manufacturing the secondary battery includes: Step 101: After the secondary battery is filled with liquid and sealed, irradiate the secondary battery with a radiation source to make the first scintillator layer generate a first optical signal.

[0129] Step 102: Collect the first optical signal through an optical sensor and convert the first optical signal into a first digital image.

[0130] Step 103: Extract the first internal structure information of the secondary battery from the first digital image.

[0131] Step 104: Judge whether the secondary battery is qualified according to the first internal structure information of the secondary battery.

[0132] If it is judged that the secondary battery is qualified, go to Step 105 to manufacture the next secondary battery. If it is judged that the secondary battery is unqualified, go to Step 106 to screen out the unqualified secondary battery and manufacture the next secondary battery.

[0133] Step 105: Manufacture the next secondary battery.

[0134] Step 106: Screen out the unqualified secondary battery and manufacture the next secondary battery.

[0135] In this embodiment, by arranging a first scintillator layer in the secondary battery, when the secondary battery is irradiated by the radiation source, after the radiation passes through the housing and penetrates the internal structure of the secondary battery, it reaches the first scintillator layer, so that the first scintillator layer generates a first optical signal. This first optical signal has the internal structure information of the secondary battery. Then, the first optical signal is collected through an optical sensor and converted into a first digital image, and the first internal structure information of the secondary battery is extracted from the first digital image, thereby judging whether the secondary battery is qualified and completing the manufacturing process of the secondary battery; accurate internal structure information of the secondary battery can be obtained without damaging the secondary battery throughout the process, improving the accuracy of the detection of the secondary battery and the safety of the secondary battery; moreover, the internal structure information of the secondary battery in the embodiment of the present application can be obtained only by irradiating with a radiation source, which also reduces the manufacturing cost of the secondary battery.

[0136] In some embodiments, the radiation source is an X-ray source, the X-ray energy of the radiation source is from 10 keV to 15 keV, such as 10 keV, 11 keV, 12 keV, 13 keV, 14 keV, 15 keV, the X-ray dose is from 10 µGy / min to 15 µGy / min, such as 10 µGy / min, 11 µGy / min, 12 µGy / min, 13 µGy / min, 14 µGy / min, 15 µGy / min, and the exposure time is from 1 s to 10 s, such as 1 s, 2 s, 4 s, 6 s, 8 s, 10 s.

[0137] In some embodiments, the focal spot size of the radiation source is from 10 µm to 30 µm, such as 10 µm, 15 µm, 20 µm, 25 µm, 30 µm, the power of the radiation source is from 100 W to 1000 W, such as 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W, 800 W, 900 W, 1000 W, the beam angle of the radiation source is in the range of 10° to 45°, for example, 10°, 20°, 30°, 40°, 45°, the distance from the focal point of the radiation source to the object FOD (Focus-to-Object Distance, the distance from the focal point of the X-ray source to the object to be detected) is from 10 mm to 50 mm, such as 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, the pulse width of the radiation source is from 10 ns to 100 ns, such as 10 ns, 20 ns, 30 ns, 40 ns, 50 ns, 60 ns, 70 ns, 80 ns, 90 ns, 100 ns, and the pulse frequency of the radiation source is from 10 kHz to 100 kHz, for example, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, 100 kHz.

[0138] In practical applications, the radiation source can irradiate the secondary battery unidirectionally or at multiple angles, so that the optical sensor can perform single or continuous imaging; in the case where the radiation source irradiates the secondary battery at multiple angles (for example, the angles are 10°, 20°, 30°, 40°, 45° respectively), the optical sensor performs continuous imaging, converts multiple first optical signals into first digital images, and thus obtains the internal structure information of the secondary battery by the obtained multiple first digital images, improving the accuracy of the obtained internal structure information of the secondary battery and the accuracy of the secondary battery detection.

[0139] Specifically, the optical sensor in this embodiment can be a CCD (Charge-Coupled Device Detector) or a CMOS (Complementary Metal-Oxide-Semiconductor Detector). The CCD detector is very sensitive to light and can detect very weak light signals. Moreover, the CCD detector can be designed into an array with a high pixel density, thereby achieving high-resolution imaging and improving the accuracy of secondary battery detection. The CMOS detector has the advantages of low power consumption, high-speed readout, and high integration. It can reduce the cost of secondary battery detection while taking into account the accuracy of secondary battery detection.

[0140] It is not difficult to find that this embodiment is a method embodiment corresponding to the above-mentioned structural embodiment of the secondary battery. The relevant technical details mentioned in the above embodiment are still valid in this embodiment. To avoid repetition, they will not be elaborated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the above embodiment.

[0141] An embodiment of the present application also relates to a method for preparing a secondary battery, which is used to prepare the secondary battery in the above embodiment. Refer to Figure 14 , which is a schematic flowchart of the method for preparing the secondary battery in this embodiment. The method for preparing the secondary battery includes: Step 201, after the secondary battery is filled with liquid and sealed, irradiate the secondary battery with a radiation source to make the first scintillator layer generate a first optical signal and the second scintillator layer generate a second optical signal.

[0142] Step 202, collect the first optical signal and the second optical signal through an optical sensor, and convert the first optical signal into a first digital image and the second optical signal into a second digital image.

[0143] Step 203, extract the first internal structure information of the secondary battery from the first digital image and extract the second internal structure information of the secondary battery from the second digital image.

[0144] Step 204, judge whether the secondary battery is qualified according to the first internal structure information and the second internal structure information of the secondary battery.

[0145] When it is judged that the secondary battery is qualified, proceed to step 205 to prepare the next secondary battery. When it is judged that the secondary battery is unqualified, proceed to step 206 to screen out the unqualified secondary battery and prepare the next secondary battery.

[0146] Step 205, prepare the next secondary battery.

[0147] Step 206: Screen out unqualified secondary batteries and prepare the next secondary battery.

[0148] In the secondary battery of this embodiment, a first scintillator layer and a second scintillator layer are provided. When the secondary battery is irradiated by a radiation source, after the radiation passes through the housing and penetrates the internal structure of the secondary battery, it reaches the first scintillator layer and the second scintillator layer, causing the first scintillator layer to generate a first optical signal and the second scintillator layer to generate a second optical signal. Both the first optical signal and the second optical signal carry the internal structure information of the secondary battery. Then, the first optical signal and the second optical signal are collected by an optical sensor, the first optical signal is converted into a first digital image, and the second optical signal is converted into a second digital image. The first internal structure information of the secondary battery is extracted from the first digital image, and the second internal structure information of the secondary battery is extracted from the second digital image, thereby determining whether the secondary battery is qualified and completing the preparation process of the secondary battery. Throughout the process, accurate internal structure information of the secondary battery can be obtained without damaging the secondary battery. The design of the two scintillator layers can further improve the accuracy of the detection of the secondary battery and enhance the safety of the secondary battery. Moreover, the internal structure information of the secondary battery in the embodiment of the present application can be obtained only by irradiating with a radiation source, which also reduces the cost of manufacturing the secondary battery.

[0149] In practical applications, the radiation source can irradiate the secondary battery unidirectionally or at multiple angles, enabling the optical sensor to perform single or continuous imaging. When the radiation source irradiates the secondary battery at multiple angles (for example, angles of 10°, 20°, 30°, 40°, 45°), the optical sensor performs continuous imaging, converting multiple first optical signals into a first digital image and multiple second optical signals into a second digital image. Thus, more accurate internal structure information of the negative electrode plate and the separator can be obtained from the multiple first digital images obtained, and more accurate internal structure information of the positive electrode plate can be obtained from the multiple second digital images obtained, improving the accuracy of the internal structure information of the secondary battery obtained and the accuracy of the detection of the secondary battery.

[0150] An embodiment of the present application also relates to an energy storage system, including a plurality of secondary batteries of the above embodiments.

[0151] In the secondary battery included in the energy storage system of the embodiment of the present application, a first scintillator layer is provided, so that accurate internal structure information of the secondary battery of the energy storage system can be obtained without damaging the energy storage system, improving the accuracy of the detection of the energy storage system and enhancing the safety of the energy storage system.

[0152] An embodiment of the present application also relates to an electrical device, including the above energy storage system.

[0153] The electrical device of the embodiment of the present application includes the energy storage system of the above embodiment, so that the internal structure information of the secondary battery of the electrical device can be obtained without damaging the electrical device, improving the accuracy of the detection of the electrical device and the safety of the electrical device.

[0154] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the present application.

Claims

1. A secondary battery, characterized in that, Comprising: a housing, an electrolyte, and at least one battery cell assembly, wherein the housing has a receiving space for receiving the electrolyte and at least one battery cell assembly, and each battery cell assembly is at least partially immersed in the electrolyte; The battery cell assembly includes: a positive electrode plate, a negative electrode plate, a separator, and a first scintillator layer; The separator is located between the positive electrode plate and the negative electrode plate; the negative electrode plate includes a negative current collector and a negative active material layer; The first scintillator layer is coated on one side of the separator close to the negative electrode plate, or the first scintillator layer is disposed between the negative current collector and the negative active material layer, or the first scintillator layer is coated on one side of the negative electrode plate close to the separator; the first scintillator layer is configured to generate a first optical signal under the irradiation of a radiation source.

2. The secondary battery according to claim 1, wherein The secondary battery further includes a second scintillator layer; the positive electrode plate includes a positive current collector and a positive active material layer; The second scintillator layer is coated on one side of the separator close to the positive electrode plate, or the second scintillator layer is disposed between the positive current collector and the positive active material layer, or the second scintillator layer is coated on one side of the positive electrode plate close to the separator; the second scintillator layer is configured to generate a second optical signal under the irradiation of the radiation source.

3. The secondary battery according to claim 2, wherein, A first protective film covers the first scintillator layer; when the first scintillator layer is disposed between the negative current collector and the negative active material layer, the negative active material layer covers the first protective film; A second protective film covers the second scintillator layer; when the second scintillator layer is disposed between the positive current collector and the positive active material layer, the positive active material layer covers the second protective film.

4. The secondary battery according to claim 3, characterized in that, When the first scintillator layer is coated on one side of the separator close to the negative electrode plate, the material of the first protective film is silicon carbide or aluminum oxide, and / or the thickness of the first protective film is 2 μm to 5 μm; When the first scintillator layer is disposed between the negative current collector and the negative active material layer, the material of the first protective film is silicon carbide or aluminum oxide, and / or the thickness of the first protective film is 2 μm to 5 μm; When the first scintillator layer is coated on one side of the negative electrode plate close to the separator, the material of the first protective film is silicon carbide or aluminum oxide, and / or the thickness of the first protective film is 2 μm to 5 μm; When the second scintillator layer is coated on one side of the separator close to the positive electrode plate, the material of the second protective film is silicon carbide or aluminum oxide, and / or the thickness of the second protective film is 2 μm to 5 μm; When the second scintillator layer is disposed between the positive current collector and the positive active material layer, the material of the second protective film is silicon carbide or aluminum oxide, and / or the thickness of the second protective film is 2 μm to 5 μm; When the second scintillator layer is disposed on the side of the positive electrode plate close to the separator, the material of the second protective film is silicon carbide or aluminum oxide, and / or, the thickness of the second protective film is 2 μm to 5 μm.

5. The secondary battery according to any one of claims 2 to 4, characterized in that, When the first scintillator layer is coated on the side of the separator close to the negative electrode plate, the thickness of the first scintillator layer is 3 μm to 8 μm; When the first scintillator layer is disposed between the negative current collector and the negative active material layer, the thickness of the first scintillator layer is 3 μm to 8 μm; When the first scintillator layer is coated on the side of the negative electrode plate close to the separator, the thickness of the first scintillator layer is 3 μm to 8 μm; When the second scintillator layer is coated on the side of the separator close to the positive electrode plate, the thickness of the second scintillator layer is 3 μm to 8 μm; When the second scintillator layer is disposed between the positive current collector and the positive active material layer, the thickness of the second scintillator layer is 3 μm to 8 μm; When the second scintillator layer is disposed on the side of the positive electrode plate close to the separator, the thickness of the second scintillator layer is 3 μm to 8 μm.

6. The secondary battery according to claim 2, characterized in that, The material of the first scintillator layer is different from that of the second scintillator layer; the material of the first scintillator layer is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS; The material of the second scintillator layer is any one of the following: Gd2O2S:Eu 3+ , Lu6O5F8:15Tb, CsI:Tl-PDMS.

7. A method for preparing a secondary battery, characterized in that For preparing the secondary battery according to claim 1, the preparation method of the secondary battery includes: After the secondary battery is filled with electrolyte and sealed, irradiate the secondary battery with the radiation source so that the first scintillator layer generates the first optical signal; Collect the first optical signal through the optical sensor and convert the first optical signal into a first digital image; extract the first internal structure information of the secondary battery from the first digital image; determine whether the secondary battery is qualified according to the first internal structure information.

8. The manufacturing method of the secondary battery according to claim 7, wherein, The secondary battery further includes a second scintillator layer; the positive electrode plate includes a positive current collector and a positive active material layer; the second scintillator layer is coated on the side of the separator close to the positive electrode plate, or, the second scintillator layer is disposed between the positive current collector and the positive active material layer, or, the second scintillator layer is disposed on the side of the positive electrode plate close to the separator; the preparation method of the secondary battery further includes: When irradiating the secondary battery with the radiation source, the second scintillator layer generates a second optical signal; Collect the second optical signal through the optical sensor and convert the second optical signal into a second digital image; extract the second internal structure information of the secondary battery from the second digital image; The determining whether the secondary battery is qualified according to the first internal structure information includes: Determine whether the secondary battery is qualified according to the first internal structure information and the second internal structure information.

9. The manufacturing method of the secondary battery according to claim 8, characterized in that, The radiation source is an X-ray source, the X-ray energy of the radiation source is 10 keV to 15 keV, the X-ray dose is 10 µGy / min to 15 µGy / min, and the exposure time is 1 s to 10 s; the focal spot size of the radiation source is 10 µm to 30 µm, the power of the radiation source is 100 W to 1000 W, the beam angle of the radiation source is 10° to 45°, the distance from the focal spot of the radiation source to the object is 10 mm to 50 mm, the pulse width of the radiation source is 10 ns to 100 ns, and the pulse frequency of the radiation source is 10 kHz to 100 kHz.

10. A energy storage system, characterized in that, Comprising: A plurality of secondary batteries according to any one of claims 1 to 6.

11. An electrical device, characterized in that, Comprising: An energy storage system according to claim 10.

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