WO2024026848A1

WO2024026848A1 - Battery cell

Info

Publication number: WO2024026848A1
Application number: PCT/CN2022/110628
Authority: WO
Inventors: 陈文汉; 王少飞
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2024-02-08
Also published as: CN118435426A

Abstract

The present application provides a battery cell, comprising a housing, an electrode assembly and at least one light-transmitting member, wherein the housing is provided with at least one observation window; the electrode assembly is accommodated in the housing, and the electrode assembly is provided with a positive electrode sheet, a separator and a negative electrode sheet, which are sequentially distributed, the positive electrode sheet being provided with a positive-electrode active material layer, the negative electrode sheet being provided with a negative-electrode active material layer, and the positive-electrode active material layer and/or the negative-electrode active material layer being an active material layer to be tested; and each light-transmitting member seals one observation window, and each light-transmitting member is arranged corresponding to the surface of one active material layer to be tested. The battery cell can be subjected to a spectrum test in situ when the actual working environment condition of an energy battery is provided, such that the problem of there being a big gap between a test situation and the actual working condition of an energy battery can be ameliorated.

Description

a battery cell

Technical field

The present application relates to the technical field of electrochemical testing, specifically to a battery cell.

Background technique

At present, when electrochemical cells designed based on spectroscopic technology are analyzed for electrode surface interfaces and electrolyte components, there is a big gap between the test results and the actual working conditions of the energy cells.

Contents of the invention

In view of the above problems, this application provides a battery cell that can improve the problem of a large gap between the test conditions and the actual working conditions of the energy battery.

The first embodiment of the application is implemented as follows:

Embodiments of the present application provide a battery cell, including: a casing, which is provided with at least one observation window; and an electrode assembly, which is accommodated in the casing. The electrode assembly is provided with a positive electrode plate, an isolation film and a negative electrode plate distributed in sequence. , the positive electrode piece is provided with a positive active material layer, the negative electrode piece is provided with a negative active material layer, the positive active material layer and/or the negative active material layer is the active material layer to be measured; and at least one light-transmitting member, each light-transmitting member The components seal an observation window, and each light-transmitting component is arranged corresponding to the surface of an active material layer to be measured.

In the technical solution of the embodiment of the present application, the battery cell is configured with a sealed casing and an electrode assembly contained in the casing, which can provide environmental conditions for the actual operation of the energy battery. On this basis, an observation window is opened in the shell, and a light-transmitting part corresponding to the surface of the active material layer to be measured is arranged in the observation window, so as to facilitate in-situ inspection of the surface interface of the active material layer to be measured and the electrolyte through the light-transmitting part. Spectral detection. Therefore, the battery cell provided by this application can perform spectral detection in situ while providing the environmental conditions for the actual working conditions of the energy battery, thereby improving the problem of a large gap between the test situation and the actual working condition of the energy battery.

In some embodiments, the light-transmitting member is configured to be close to the surface of the corresponding active material layer to be measured under the action of external force. In this embodiment, the light-transmitting member can be close to the surface of the active material layer to be measured under the action of external force, so that the thickness of the liquid film between the light-transmitting member and the surface of the active material layer to be measured can be adjusted according to the detection needs, which can better achieve Spectral detection of the surface interface of the active material layer to be measured and the electrolyte.

In some embodiments, the light-transmitting member is fixedly connected to the edge of the observation window; the housing is configured to: when the light-transmitting member approaches the surface of the corresponding active material layer to be measured under the action of external force, the light-transmitting member can move along with the movement of the light-transmitting member. deformation. In this embodiment, the position of the light-transmitting component relative to the surface of the active material layer to be measured is adjusted through the deformation of the housing, which facilitates the fixed connection between the light-transmitting component and the edge of the observation window and ensures good sealing of the housing.

In some embodiments, the thickness of the shell wall of the housing ranges from 30 μm to 60 μm. In this embodiment, the shell wall of the shell has a suitable thickness, which can better realize the position adjustment of the light-transmitting member relative to the surface of the active material layer to be measured through the deformation of the shell.

In some embodiments, the light-transmitting member is slidably and sealably disposed through the observation window. In this embodiment, the position of the light-transmitting part relative to the surface of the active material layer to be measured is adjusted by sliding the light-transmitting part in the observation window, so that the housing and the light-transmitting part can be configured separately, which facilitates the overall configuration of the battery cells. and assembly.

In some embodiments, among the positive active material layer and the negative active material layer, one is the active material layer to be tested and the other is the preset active material layer; the active material layer to be tested is located on the electrode piece close to the separator. One side; in the observation window and light-transmitting part corresponding to each active material layer to be measured, the observation window is located on the side of the shell corresponding to the preset active material layer, and the light-transmitting part penetrates the isolation film and the preset active material layer. of pole piece. In this embodiment, the light-transmitting member penetrates the isolation film and the pole piece where the preset active material layer is located, and the isolation film and the pole piece where the preset active material layer is located have a limiting effect on the light-transmitting member in the lateral direction, so that the light-transmitting member The movement when close to the surface of the corresponding active material layer to be measured is more stable and controllable, which is beneficial to ensuring the convenience of operation and the accuracy of detection.

In some embodiments, the negative active material layer is the active material layer to be measured and is located on the side of the negative electrode piece close to the isolation film; the casing is provided with an observation window, and the observation window is located on the side of the casing corresponding to the positive electrode piece. ; There is a light-transmitting part inside the battery cell, and the light-transmitting part can movably penetrate the isolation film and the positive electrode piece, so that the light-transmitting part corresponds to the negative active material layer and can be close to the surface of the negative active material layer under the action of external force . In this embodiment, the light-transmitting member is corresponding to the surface of the inner active material layer in the negative electrode piece, and is used to realize spectral detection of the surface interface of the inner active material layer in the negative electrode piece and the electrolyte. Among them, the light-transmitting member penetrates the isolation film and the positive electrode piece, and the isolation film and the positive electrode piece limit the light-transmitting member in the transverse direction, so that the movement of the light-transmitting member is close to the surface of the inner active material layer in the negative electrode piece. It is more stable and controllable, which helps ensure the convenience of operation and the accuracy of detection.

In some embodiments, a portion of each light-transmissive member is contained within the housing and a portion is located outside the housing. In this embodiment, the part of the light-transmitting component is located outside the casing, so that force can be exerted on the light-transmitting component outside the battery cell to adjust the position.

In some embodiments, each light-transmitting member includes a first light-transmitting section and a second light-transmitting section connected to each other, and the first light-transmitting section is located on a side of the second light-transmitting section close to the surface of the active material layer to be measured; The first light-transmitting segment is in the shape of a column, and at least part of it is accommodated in the housing. The second light-transmitting segment is in the shape of a spherical cover and is located outside the housing. In this embodiment, the second light-transmitting section located outside the shell is configured in a spherical cover shape, which has a better light reflection effect during spectrum detection, which is beneficial to signal collection during spectrum detection. When the second light-transmitting section is configured in the shape of a spherical cover, the first light-transmitting section is configured in a columnar shape, which facilitates the overall manufacturing of the light-transmitting part; since at least a part of the first light-transmitting section is accommodated in the housing, the first light-transmitting section The light segment is configured in a columnar shape and is convenient for sealing with the observation window.

In some embodiments, the first light-transmitting segment is cylindrical, and the light-transmitting member meets at least one of the following conditions (a) to (c); (a) the diameter of the first light-transmitting segment is 5 mm to 12 mm; ( b) The diameter of the first light-transmitting segment is 6mm~8mm; (c) The arc of the second light-transmitting segment is 0.7~1.5. In this embodiment, the first light-transmitting section is controlled to have an appropriate size to ensure that the light-transmitting part has a better light-transmitting effect, which is conducive to light excitation during spectrum detection; at the same time, the light-transmitting part is positioned on the electrode assembly corresponding to The area has an appropriate proportion, for example, when the light-transmitting member is configured to penetrate the isolation film and the pole piece where the preset active material layer is located, so that the electrolyte can better wet the electrode assembly. Controlling the second light-transmitting section to have an appropriate curvature ensures that the light-transmitting part has a better light reflection effect, which is beneficial to signal collection during spectrum detection.

In some embodiments, each light-transmitting member is disposed corresponding to the middle surface of an active material layer to be measured. In this embodiment, the light-transmitting member is aligned with the middle surface of the active material layer to be measured, and the detected area can more accurately reflect the changes in the overall interface and the electrolyte, making the detection results more accurate.

In some embodiments, the electrode assembly is in the form of a laminate. In this embodiment, in the stacked electrode assembly, the surface of the active material layer to be measured is flat, the light-transmitting component can easily correspond to the surface of the active material layer to be measured, the structural configuration of the battery cell is simple, and the spectral detection is reliable. Good sex.

In some embodiments, the light-transmitting component is made of calcium fluoride, silicon dioxide, silicon nitride, polytetrafluoroethylene, glass or quartz. In this embodiment, the light-transmitting component is made of a specific material to ensure better light-transmitting and light-reflecting effects, which is beneficial to light excitation and signal collection during spectrum detection.

In some embodiments, the housing is an aluminum plastic film. In this embodiment, a specific material is selected for the shell, which can better meet usage requirements such as strength and corrosion resistance; at the same time, the position of the light-transmitting component relative to the surface of the active material layer to be measured is adjusted through the deformation of the shell. In this case, the position adjustment of the light-transmitting member can also be better achieved through the deformation of the housing.

In some embodiments, the battery cell further includes a reference electrode. The reference electrode is provided on an isolation film. The reference electrode and the positive electrode piece are separated by the isolation film, and the reference electrode and the negative electrode piece are separated by an isolation film. membrane separated. In this embodiment, the set reference electrode can directly detect the change of the pole piece, and the battery cell can realize spectrum detection and reference detection at the same time, making the testing method of the battery cell more flexible. When the two testing methods are combined, the test information is more accurate. Comprehensive and more accurate test results.

In some embodiments, the reference electrode is made of copper, Li ₄ Ti ₅ O ₁₂ , LiVO ₂ , Li _x MoO ₂ , LiWO ₂ , Li ₆ Fe ₂ O ₃ or LiNb ₂ O ₅ . In this embodiment, the reference electrode is made of a specific material, which has good lithium insertion performance and stability, ensuring long-term stable and efficient reference detection.

The above description is only an overview of the technical solutions of the present application. In order to have a clearer understanding of the technical means of the present application, they can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable. , the specific implementation methods of the present application are specifically listed below.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a first structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 2 is a first partial axial schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 3 is a first partial cross-sectional schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 4 is a schematic cross-sectional view of an electrode assembly provided by an embodiment of the present application;

Figure 5 is a second structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 6 is a third structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 7 is a fourth structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 8 is a fifth structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 9 is a schematic diagram of the sixth structure of a battery cell provided by an embodiment of the present application;

Figure 10 is a seventh structural schematic diagram of a battery cell provided by an embodiment of the present application;

Figure 11 is a second partial axial side view of a battery cell provided by an embodiment of the present application;

Figure 12 is a second partial cross-sectional schematic diagram of a battery cell provided by an embodiment of the present application.

icon:

10-battery cell;

100-shell; 110-observation window;

200-electrode assembly; 210-positive electrode piece; 220-isolation film; 230-negative electrode piece;

211-positive electrode current collector; 212-positive electrode active material layer; 213-positive electrode tab;

231-negative electrode current collector; 232-negative electrode active material layer; 233-negative electrode tab;

240-active material layer to be tested; 250-preset active material layer;

300-Light-transmitting part; 310-First light-transmitting section; 320-Second light-transmitting section;

400-Reference electrode.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and are therefore only used as examples and cannot be used to limit the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field belonging to this application; the terms used herein are for the purpose of describing specific embodiments only and are not intended to be used in Limitation of this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

In the description of the embodiments of this application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. A specific order or priority relationship.

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description. It is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of this application, unless otherwise clearly stated and limited, technical terms such as "installation", "connection", "connection" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection or a removable connection. Disassemble and connect, or integrate; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

Reference herein to "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of simplicity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the height, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall height, length and width of the integrated device, are only illustrative illustrations and should not constitute any limitation on the present application. .

Currently, electrochemical cells are designed to study the changes in electrode materials and electrolytes during electrochemical charge and discharge. Among them, spectroscopic technology can collect spectral information while obtaining electrical information, and understand the structure and properties of the electrode surface in real time as they change with the electrochemical environment. changes resulting from changes.

The applicant noted that at present, when analyzing the electrode surface interface and electrolyte composition of an electrochemical cell designed based on spectroscopic technology, whether it is in internal reflection mode or external reflection mode, it must be carried out in a glass cell containing electrolyte. , and conduct electrochemical reaction studies by inserting electrodes. Due to the large gap between the test environment and the actual working environment of the energy battery, there is a large gap between the test conditions and the actual working conditions of the energy battery.

Based on this, this application designs a battery cell 10 that can meet the actual working needs of energy batteries based on spectral technology detection. Therefore, it can provide in-situ spectral detection under the environmental conditions for the actual working of energy batteries, thereby improving There is a big gap between the test conditions and the actual working conditions of the energy battery.

Next, the battery cell 10 proposed in the embodiment of the present application will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1 to 3 , the present application provides a battery cell 10 , including a casing 100 , an electrode assembly 200 and a light-transmitting member 300 . The housing 100 is provided with at least one observation window 110 . The electrode assembly 200 is accommodated in the casing 100. The electrode assembly 200 is provided with a positive electrode piece 210, an isolation film 220 and a negative electrode piece 230 distributed in sequence. The positive electrode piece 210 is provided with a positive active material layer 212, and the negative electrode piece 230 is provided with a negative electrode. The active material layer 232 , the positive active material layer 212 and/or the negative active material layer 232 is the active material layer 240 to be tested. There is at least one light-transmitting member 300 , each light-transmitting member 300 seals an observation window 110 , and each light-transmitting member 300 is arranged corresponding to the surface of an active material layer 240 to be measured.

The battery cell 10 refers to the smallest unit used for electrochemical testing and may include a casing 100, an electrode assembly 200 and an electrolyte. The electrode assembly 200 and the electrolyte are both housed in the casing 100.

The casing 100 is a shell structure capable of sealing the electrode assembly 200 and the electrolyte inside, and has a sealed space inside for accommodating the electrode assembly 200 and the electrolyte. The housing 100 can be of various shapes and sizes. The shape and size of the housing 100 can be determined according to the specific shape and size of the electrode assembly 200 . For example, the shape can be a cuboid, a cylinder, a hexagonal prism, etc. The housing 100 can be made of various materials, such as but not limited to copper, iron, aluminum, stainless steel, aluminum alloy and other metals.

The observation window 110 is an opening opened in the shell wall of the housing 100 , which penetrates the shell wall and communicates with the internal sealed space. The observation window 110 can be of various shapes and sizes. The shape and size of the observation window 110 can be determined according to the specific shape and size of the light-transmitting member 300 . For example, the shape can be circular, elliptical, etc.

The electrode assembly 200 may be composed of a positive electrode piece 210 , a negative electrode piece 230 and a separator 220 . The battery cell 10 mainly relies on the movement of metal ions between the positive electrode piece 210 and the negative electrode piece 230 to work. The form of the electrode assembly 200 is not limited, and may be a rolled structure or a laminated structure.

Referring to Figure 4, the positive electrode sheet 210 includes a positive electrode current collector 211 and a positive electrode active material layer 212. Taking the lithium ion battery cell 10 as an example, the material of the positive electrode current collector 211 can be aluminum; the positive electrode active material layer 212 can be disposed on the positive electrode. The cathode active material in the cathode active material layer 212 may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganate, or the like.

The material of the isolation film 220 may be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.

Referring to FIG. 4 , the negative electrode sheet 230 includes a negative electrode current collector 231 and a negative electrode active material layer 232 . Taking the lithium ion battery cell 10 as an example, the material of the negative electrode current collector 231 can be copper; the negative electrode active material layer 232 can be disposed on two surfaces or one of the surfaces of the negative electrode current collector 231 that are relatively distributed along the thickness direction. The negative active material in layer 232 may be carbon, silicon, etc.

The light-transmitting member 300 refers to a structure that can allow light for spectral detection to pass through. The light that it allows to pass through is, for example, visible light, infrared light, ultraviolet light, Raman light, X-rays, etc.

Each light-transmitting member 300 is arranged corresponding to the surface of an active material layer 240 to be measured, which means that the surface of the side of the light-transmitting member 300 close to the active material layer 240 to be measured is opposite to the surface of the active material layer 240 to be measured. The two surfaces are illustratively parallel to each other, and the two surfaces may be in a relative position relationship in contact with each other, or may be in a relative position relationship with a certain gap.

The active material layer 240 to be tested is an active material layer whose surface is arranged corresponding to the light-transmitting member 300. It is used to illustrate the arrangement of the light-transmitting member 300 in the battery cell 10. The active material layer 240 to be tested may be a positive electrode active material. Layer 212 may also be a negative active material layer 232, and its materials and specifications may be designed with reference to conventional active material layers.

The positive active material layer 212 and/or the negative active material layer 232 is the active material layer to be tested 240 , which means that in the battery cell 10 , only the light-transmitting member 300 corresponding to the negative active material layer 232 can be configured, as shown in FIG. 1 As shown in FIG. 5 , only the light-transmitting member 300 corresponding to the positive active material layer 212 may be configured, as shown in FIG. 5 ; the light-transmitting member 300 corresponding to the negative active material layer 232 and the positive active material layer 212 may also be configured at the same time. The corresponding light-transmitting member 300 is shown in FIG. 6 and FIG. 7 .

In the technical solution of the embodiment of the present application, the battery cell 10 is configured with a sealed casing 100 and an electrode assembly 200 contained in the casing 100, which can provide environmental conditions for the actual operation of the energy battery. On this basis, an observation window 110 is opened in the housing 100, and a light-transmitting member 300 corresponding to the surface of the active material layer 240 to be measured is arranged in the observation window 110, so that the active material layer 240 to be measured can be in situ through the light-transmitting member 300. The surface interface and the electrolyte are subjected to spectral detection. Therefore, the battery cell 10 provided by the present application can perform spectral detection in situ while providing the environmental conditions for the actual working conditions of the energy battery, thereby improving the problem of a large gap between the test conditions and the actual working conditions of the energy battery.

In some embodiments, the light-transmitting member 300 is configured to be close to the surface of the corresponding active material layer 240 to be measured under the action of external force.

The way in which the light-transmitting member 300 moves close to the surface of the corresponding active material layer 240 to be measured is not limited. For example, the housing 100 may be deformed with the movement of the light-transmitting member 300 , or the light-transmitting member 300 may be moved relative to the observation window 110 way of movement.

The light-transmitting member 300 can be close to the surface of the corresponding active material layer 240 to be measured under the action of external force. Of course, when the force is lost, the light-transmitting member 300 can also maintain the adjusted position (for example, the light-transmitting member 300 moves relative to the observation window 110 way) or away from the surface of the corresponding active material layer 240 to be measured (for example, the way in which the housing 100 deforms with the movement of the light-transmitting member 300); when receiving a reverse force, the light-transmitting member 300 can also move away from the corresponding surface to be measured. The surface of the active material layer 240 is measured.

The light-transmitting member 300 can move under the action of external force. The light-transmitting member 300 may be directly stressed. For example, a part of the light-transmitting member 300 may protrude from the observation window 110 , as shown in FIGS. 1 and 8 . It shows that when performing spectrum detection through the light-transmitting member 300, force can be directly applied to the part of the light-transmitting member 300 that protrudes from the observation window 110; the force-bearing mode of the light-transmitting member 300 can be indirect force, for example, the light-transmitting member 300 can be subjected to indirect force. The member 300 is flush with the observation window 110. As shown in FIG. 9, by exerting a deformation force on the housing 100, the light-transmitting member 300 receives an indirect force and moves along with the deformation of the housing 100.

As an example, in order to ensure the accuracy of the moving distance of the light-transmitting member 300, external force is provided to the light-transmitting member 300 through, for example, a driving structure connected to a micrometer. When driving, for example, the side of the housing 100 with the observation window 110 is facing down, and then the other side of the driving housing 100 opposite to the observation window 110 is pressed downward through the driving structure connected with a micrometer (that is, in this state the upper surface).

When the light-transmitting member 300 moves close to the surface of the corresponding active material layer 240 to be measured, it has at least a partial velocity along the thickness direction of the electrode assembly 200. For example, the light-transmitting member 300 can be configured to move close to the corresponding surface along the thickness direction of the electrode assembly 200. On the surface of the active material layer 240 to be measured, the movement direction of the light-transmitting member 300 may also form a certain angle with the thickness direction of the electrode assembly 200 .

In this embodiment, the light-transmitting member 300 can be close to the surface of the active material layer 240 to be measured under the action of external force, so that the thickness of the liquid film between the light-transmitting member 300 and the surface of the active material layer 240 to be measured can be adjusted according to detection needs. The spectral detection of the surface interface of the active material layer 240 to be measured and the electrolyte is better realized.

In some embodiments, the light-transmitting member 300 is fixedly connected to the edge of the observation window 110; the housing 100 is configured to: when the light-transmitting member 300 approaches the surface of the corresponding active material layer 240 to be measured under the action of external force, it can The movement of the optical component 300 causes deformation.

The edge fixed connection between the light-transmitting member 300 and the observation window 110 means that the two are relatively fixed, for example, through sealing structures such as sealant and sealing rings.

In this embodiment, the position of the light-transmitting member 300 relative to the surface of the active material layer 240 to be measured is adjusted through the deformation of the housing, which facilitates the fixed connection between the light-transmitting member 300 and the edge of the observation window 110 and ensures that the housing 100 has better Sealing.

In some embodiments, the thickness of the shell wall of the housing 100 is 30 μm˜60 μm.

The thickness of the shell wall of the shell 100 refers to the size of the shell wall of the shell 100 in a direction perpendicular to its surface.

As an example, the thickness is, for example, but not limited to, any one point value of 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm and 60 μm or any range value between the two. If the thickness is small, the strength of the housing 100 is relatively low; if the thickness is large, it is not conducive to the deformation of the housing 100 .

In this embodiment, the shell wall of the shell 100 has a suitable thickness, which can better realize the position adjustment of the light-transmitting member 300 relative to the surface of the active material layer 240 to be measured through the deformation of the shell.

In some embodiments, the light-transmitting member 300 is slidably and sealably disposed through the observation window 110 .

In this embodiment, the light-transmitting member 300 is configured to be able to seal and slide relative to the observation window 110 under the action of external force, so as to be close to the surface of the corresponding active material layer 240 to be measured.

The fact that the light-transmitting member 300 is slidably and sealably disposed through the observation window 110 means that the two can move relative to each other in a sealed state, for example, a sealing ring is nested between the two to allow relative movement.

In this embodiment, the position of the light-transmitting part 300 relative to the surface of the active material layer 240 to be measured is adjusted by sliding the light-transmitting part 300 in the observation window 110, so that the housing and the light-transmitting part 300 can be configured separately, which is convenient for the battery. The overall configuration and assembly of the unit 10.

In some embodiments, one of the positive active material layer 212 and the negative active material layer 232 is the active material layer to be tested 240 and the other is the preset active material layer 250; the active material layer to be tested 240 is located on the electrode where it is located. The side of the sheet close to the isolation film 220; in the observation window 110 and the light-transmitting member 300 corresponding to each active material layer 240 to be measured, the observation window 110 is located on the side of the housing 100 corresponding to the preset active material layer 250. The optical component 300 penetrates the isolation film 220 and the pole piece where the preset active material layer 250 is located.

The preset active material layer 250 is an active material layer in the pole piece adjacent to the active material layer 240 to be measured. It is used to illustrate the arrangement of the light-transmitting member 300 in the battery cell 10. The preset active material layer 250 It can be the positive active material layer 212 or the negative active material layer 232, and its materials and specifications can be designed with reference to conventional active material layers.

In this application, the light-transmitting member 300 can pass through a part of the structure of the electrode assembly 200 so as to be disposed corresponding to the surface of the active material layer 240 to be measured located inside the electrode assembly 200, as shown in Figure 1; the light-transmitting member 300 can also be placed on The exterior of the electrode assembly 200 is disposed corresponding to the surface of the active material layer 240 to be measured located outside the electrode assembly 200, as shown in FIGS. 7 and 10 .

In the embodiment shown in FIG. 1 , the light-transmitting member 300 is inserted through the isolation film 220 and the pole piece where the preset active material layer 250 is located, and the isolation film 220 and the pole piece where the preset active material layer 250 is located are opposite to each other laterally. The limiting function of the light-transmitting member 300 makes the movement of the light-transmitting member 300 when close to the corresponding surface of the active material layer 240 to be measured more stable and controllable, which is beneficial to ensuring the convenience of operation and the accuracy of detection.

Referring to Figure 1, in some embodiments, the negative active material layer 232 is the active material layer 240 to be measured, and is located on the side of the negative electrode piece 230 close to the isolation film 220; the casing 100 is provided with an observation window 110, and the observation window 110 is located on The side of the casing 100 corresponding to the positive electrode piece 210; a light-transmitting member 300 is provided in the battery cell 10, and the light-transmitting member 300 can movablely penetrate the isolation film 220 and the positive electrode piece 210, so that the light-transmitting member 300 It corresponds to the negative electrode active material layer 232 and can be close to the surface of the negative electrode active material layer 232 under the action of external force.

The negative active material layer 232 is the active material layer to be measured 240 , that is to say, the positive active material layer 212 is the preset active material layer 250 .

In this embodiment, the light-transmitting member 300 is corresponding to the surface of the inner active material layer in the negative electrode piece 230 to achieve spectral detection of the surface interface of the inner active material layer in the negative electrode piece 230 and the electrolyte. Among them, the light-transmitting member 300 penetrates the isolation film 220 and the positive electrode piece 210. The isolation film 220 and the positive electrode piece 210 limit the light-transmitting member 300 in the lateral direction, so that the light-transmitting member 300 is close to the inner side of the negative electrode piece 230. The movement on the surface of the active material layer is more stable and controllable, which is beneficial to ensuring the convenience of operation and the accuracy of detection.

Referring to FIGS. 1 and 8 , in some embodiments, a portion of each light-transmitting member 300 is accommodated within the housing 100 , and a portion is located outside the housing 100 .

A part of the light-transmitting member 300 is accommodated in the housing 100 , which means that the light-transmitting member 300 has a portion that is accommodated in the sealed space of the housing 100 . The part of the light-transmitting member 300 located outside the housing 100 means that the light-transmitting member 300 has a portion protruding from the observation window 110 , as shown in FIGS. 1 and 8 .

In this application, the light-transmitting member 300 may include parts located outside the housing 100, as shown in FIGS. 1 and 8; or may not include parts located outside the housing 100, as shown in FIG. 9.

In the embodiment shown in FIGS. 1 and 8 , part of the light-transmitting member 300 is located outside the housing 100 , which facilitates position adjustment by exerting force on the light-transmitting member 300 outside the battery cell 10 .

Referring to Figure 1, in some embodiments, each light-transmitting member 300 includes a first light-transmitting section 310 and a second light-transmitting section 320 that are connected to each other. The first light-transmitting section 310 is located near the second light-transmitting section 320 to be measured. On one side of the surface of the active material layer 240 , the first light-transmitting section 310 is in the shape of a column, and at least a part of it is accommodated in the housing 100 . The second light-transmitting section 320 is in the shape of a spherical cover and is located outside the housing 100 .

The first light-transmitting section 310 and the second light-transmitting section 320 refer to different parts of the light-transmitting member 300, and they are connected integrally, for example.

In this application, the shape of the first light-transmitting segment 310 is not limited, such as but not limited to cylindrical shape, elliptical cylindrical shape, prism shape, etc. The shape of the second light-transmitting segment 320 is not limited. In addition to the spherical cap shape, it may also be cylindrical (as shown in FIG. 8 ).

As shown in FIG. 1 , in this embodiment, the second light-transmitting section 320 located outside the housing 100 is configured in a spherical cover shape, which has a better light reflection effect during spectrum detection, which is beneficial to signal collection during spectrum detection. When the second light-transmitting section 320 is configured in a spherical cover shape, the first light-transmitting section 310 is configured in a columnar shape to facilitate the overall manufacturing of the light-transmitting component 300; since at least a part of the first light-transmitting section 310 is accommodated in the housing 100 Inside, the first light-transmitting section 310 is configured in a columnar shape to facilitate sealing cooperation with the observation window 110 .

In some embodiments, the first light-transmitting segment 310 is cylindrical, and the light-transmitting member 300 meets at least one of the following conditions (a) to (c); (a) the diameter of the first light-transmitting segment 310 is 5 mm to 5 mm. 12mm; (b) the diameter of the first light-transmitting section 310 is 6mm~8mm; (c) the arc of the second light-transmitting section 320 is 0.7~1.5.

Based on (a) and (b), the diameter of the first light-transmitting segment 310 is, for example, but not limited to, any one of 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm and 12mm or any value between the two. range value.

In condition (c), radian is the measurement unit of angle, the unit abbreviation is rad, and the central angle subtended by an arc whose arc length is equal to the radius is 1 radian. The radian of the second light-transmitting section 320 is, for example, but not limited to, any one point value among 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4 and 1.5 or any range value between the two.

In this embodiment, conditions (a) and (b) control the first light-transmitting section 310 to have an appropriate size, ensuring that the light-transmitting member 300 has a better light-transmitting effect, which is beneficial to light excitation during spectrum detection; at the same time, so that The light-transmitting member 300 has an appropriate proportion of the corresponding area on the electrode assembly 200. For example, when the light-transmitting member 300 is configured to penetrate the isolation film 220 and the pole piece where the preset active material layer 250 is located, the electrolyte solution The electrode assembly 200 can be well wetted. Condition (c) controls the second light-transmitting section 320 to have an appropriate curvature to ensure that the light-transmitting part 300 has a better light reflection effect, which is beneficial to signal collection during spectrum detection.

Referring to FIG. 1 , in some embodiments, each light-transmitting member 300 is disposed corresponding to the middle surface of an active material layer 240 to be measured.

The middle surface of the active material layer to be measured 240 refers to an area close to the center of the surface of the active material layer to be measured 240 , for example, a certain area passing through the center point of the surface of the active material layer to be measured 240 .

In this application, the light-transmitting member 300 is not limited to being disposed corresponding to the middle part of the surface of the active material layer 240 to be measured. It may also be disposed corresponding to the portion close to the edge of the surface of the active material layer 240 to be measured.

As shown in FIG. 1 , in this embodiment, the light-transmitting member 300 corresponds to the middle surface of the active material layer 240 to be measured. The detected area can more accurately reflect the changes in the overall interface and the electrolyte, making the detection results more accurate.

In some embodiments, electrode assembly 200 is an assembly in the form of a laminate.

In this embodiment, in the electrode assembly 200 in the form of a laminate, the surface of the active material layer 240 to be measured is a plane, and the light-transmitting member 300 can easily correspond to the surface of the active material layer 240 to be measured. The structural configuration of the battery cell 10 Simple and reliable spectral detection.

In some embodiments, the light-transmitting member 300 is made of calcium fluoride, silicon dioxide, silicon nitride, polytetrafluoroethylene, glass or quartz.

In this embodiment, a specific material is selected for the light-transmitting component 300 to ensure better light-transmitting and light-reflecting effects, which is beneficial to light excitation and signal collection during spectrum detection.

In some embodiments, the housing 100 is an aluminum plastic film.

In this embodiment, a specific material is selected for the shell 100, which can better meet the usage requirements such as strength and corrosion resistance. At the same time, the deformation of the shell realizes the deformation of the light-transmitting member 300 relative to the surface of the active material layer 240 to be measured. In the case of position adjustment, the position adjustment of the light-transmitting member 300 can also be better achieved through the deformation of the housing.

Referring to Figures 11 and 12, in some embodiments, the battery cell 10 further includes a reference electrode 400. The reference electrode 400 is provided on the isolation film 220. The reference electrode 400 and the positive electrode plate 210 are separated by the isolation film 220. open, and the reference electrode 400 and the negative electrode piece 230 are separated by the isolation film 220 .

The reference electrode 400 is an electrode used as a reference for comparison when measuring the potential of the negative electrode piece 230 and the like. It can have a variety of materials, shapes, etc.

The arrangement form of the reference electrode 400 is not limited. For example, the reference electrode 400 is arranged in the isolation in a manner similar to the tab 213 in the manner in which the positive electrode tab 213 is arranged in the positive electrode piece 210 (or the negative electrode tab 233 is arranged in the negative electrode tab 230). Membrane 220.

In this embodiment, the reference electrode 400 is configured to directly detect the change of the pole piece, and the battery cell 10 can simultaneously implement spectral detection and reference detection, making the testing method of the battery cell 10 more flexible. When the two testing methods are combined The test information is more comprehensive and the test results are more accurate.

In some embodiments, the reference electrode 400 is made of copper, Li ₄ Ti ₅ O ₁₂ , LiVO ₂ , Li _x MoO ₂ , LiWO ₂ , Li ₆ Fe ₂ O ₃ or LiNb ₂ O ₅ .

In this embodiment, the reference electrode 400 is made of a specific material, which has good lithium embedding performance and stability, ensuring long-term stable and efficient reference detection.

According to some embodiments of the present application, referring to FIGS. 1 and 11 , the electrode assembly 200 is an assembly in the form of a laminate, and the battery cell 10 further includes a reference electrode 400 . The negative active material layer 232 is the active material layer to be tested 240 and is located on the side of the negative electrode piece 230 close to the isolation film 220 . The housing 100 is provided with an observation window 110 , and the observation window 110 is located on the side of the housing 100 corresponding to the positive electrode piece 210 . There is a light-transmitting member 300 inside the battery cell 10. The light-transmitting member 300 can movably penetrate the isolation film 220 and the positive electrode plate 210. The light-transmitting member 300 includes a first light-transmitting section 310 and a second light-transmitting section 310 connected to each other. In the light section 320, the first light-transmitting section 310 is in the shape of a column, and the second light-transmitting section 320 is in the shape of a spherical cover.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. The scope shall be covered by the claims and description of this application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any way. The application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell including:

A housing with at least one observation window;

Electrode assembly, the electrode assembly is accommodated in the casing, the electrode assembly is provided with a positive electrode piece, an isolation film and a negative electrode piece distributed in sequence, the positive electrode piece is provided with a positive active material layer, and the negative electrode The sheet is provided with a negative active material layer, and the positive active material layer and/or the negative active material layer is the active material layer to be tested; and

At least one light-transmitting member, each of the light-transmitting members seals one of the observation windows, and each of the light-transmitting members is disposed corresponding to a surface of one of the active material layers to be measured.
The battery cell according to claim 1, wherein the light-transmitting member is configured to be close to the corresponding surface of the active material layer to be measured under the action of external force.
The battery cell according to claim 2, wherein the light-transmitting member is fixedly connected to an edge of the observation window; and the housing is configured such that when the light-transmitting member approaches the corresponding When the surface of the active material layer is to be measured, deformation may occur along with the movement of the light-transmitting member.
The battery cell according to claim 3, wherein the thickness of the shell wall of the outer shell is 30 μm to 60 μm.
The battery cell according to claim 2, wherein the light-transmitting member is slidably and sealably disposed through the observation window.
The battery cell according to any one of claims 1 to 5, wherein when one of the positive electrode active material layer and the negative electrode active material layer is the active material layer to be measured, the other is a predetermined active material layer. Assume an active material layer;

The active material layer to be measured is located on the side of the pole piece close to the isolation film; the observation window and the light-transmitting member corresponding to each active material layer to be measured are located in the observation window. On the side of the housing corresponding to the preset active material layer, the light-transmitting member penetrates the isolation film and the pole piece where the preset active material layer is located.
The battery cell according to any one of claims 1 to 6, wherein the negative active material layer is the active material layer to be measured and is located on the side of the negative electrode piece close to the isolation film; The casing is provided with an observation window, and the observation window is located on a side of the casing corresponding to the positive electrode piece; the battery cell is provided with one of the light-transmitting parts, and the transparent part is The light member can movably penetrate the isolation film and the positive electrode piece, so that the light-transmitting member corresponds to the negative electrode active material layer and can be close to the surface of the negative electrode active material layer under the action of external force.
The battery cell according to any one of claims 1 to 7, wherein a portion of each of the light-transmitting members is accommodated in the casing, and a portion is located outside the casing.
The battery cell according to any one of claims 1 to 8, wherein each of the light-transmitting members includes a first light-transmitting section and a second light-transmitting section connected to each other, and the first light-transmitting section is located at The second light-transmitting section is close to the side of the surface of the active material layer to be measured; the first light-transmitting section is columnar, and at least part of it is accommodated in the housing; the second light-transmitting section is a sphere Cover-shaped and located outside the housing.
The battery cell according to claim 9, wherein the first light-transmitting section is cylindrical, and the light-transmitting member satisfies at least one of the following conditions (a) to (c);

(a) The diameter of the first light-transmitting segment is 5 mm to 12 mm;

(b) The diameter of the first light-transmitting segment is 6 mm to 8 mm;

(c) The second light-transmitting segment has an arc of 0.7 to 1.5.
The battery cell according to any one of claims 1 to 10, wherein each of the light-transmitting members is disposed corresponding to a middle surface of one of the active material layers to be measured.
The battery cell according to any one of claims 1 to 11, wherein the electrode assembly is a laminate-form assembly.
The battery cell according to any one of claims 1 to 12, wherein the light-transmitting member is made of calcium fluoride, silicon dioxide, silicon nitride, polytetrafluoroethylene, glass or quartz.
The battery cell according to any one of claims 1 to 13, wherein the outer casing is an aluminum plastic film.
The battery cell according to any one of claims 1 to 14, wherein the battery cell further includes a reference electrode, the reference electrode is provided on the isolation film, the reference electrode and the The positive electrode pieces are separated by the isolation film, and the reference electrode and the negative electrode piece are separated by the isolation film.
The battery cell according to claim 15, wherein the reference electrode is made of copper, Li 4 Ti 5 O 12 , LiVO 2 , Li x MoO 2 , LiWO 2 , Li 6 Fe 2 O 3 or LiNb 2 O5 .