Pouch battery cell structure and battery
By using foil and separator with high elongation and high tensile strength, combined with end-cap tape with low peel force, a cell structure is formed, which solves the safety problem of the battery under compression and heavy impact, and achieves a balance between high energy density and safety of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- EVE ENERGY CO LTD
- Filing Date
- 2025-03-27
- Publication Date
- 2026-06-09
AI Technical Summary
Existing batteries cannot simultaneously achieve high energy density and safety under compression and heavy impact. They are prone to short circuits, thermal runaway, and explosions due to compression deformation.
The battery cell structure is formed by using positive electrode sheets and negative electrode foils with high elongation and high tensile strength, as well as a separator with high tensile strength, combined with a finishing adhesive paper with low peel strength, thereby enhancing the battery's impact resistance.
This improves battery safety under compression and heavy impact, prevents foil breakage, and enhances the stability and safety of the battery structure.
Smart Images
Figure CN224342289U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to a pouch cell structure and battery. Background Technology
[0002] The battery crush test examines the safety of the battery under mechanical contact stress, which is the process by which the battery is deformed due to compression, leading to fire and explosion of the power battery.
[0003] During a compression test, as the pressure on the battery increases, the battery structure deforms. The positive and negative electrode plates inside the battery may puncture the separator, causing them to come into contact and resulting in a short circuit. This generates a large amount of Joule heat, causing the battery temperature to rise instantaneously. Chemical reactions occur between the positive and negative electrode materials, electrolyte, binder, and other materials, triggering thermal runaway and ultimately inducing a fire. The internal thermal reaction also produces a large amount of gas, which may explode upon reaching a certain pressure.
[0004] Currently available batteries cannot simultaneously achieve both high energy density and high withstand rates of compression and heavy impacts, resulting in low battery capacity and structural safety. Therefore, a novel technical solution is urgently needed to address these issues. Utility Model Content
[0005] This application provides a soft-pack battery cell structure and battery. The soft-pack battery cell structure can safely withstand compression and heavy object impacts, thereby improving battery safety.
[0006] This application provides a pouch cell structure, including:
[0007] A positive electrode, a separator, and a negative electrode are stacked in sequence, and the positive electrode, the separator, and the negative electrode are wound in the same direction to form a battery cell;
[0008] Wherein, the elongation of the foil of the positive electrode is greater than or equal to a first elongation, and the tensile strength of the foil of the positive electrode is greater than or equal to a first tensile strength, and / or; the elongation of the foil of the negative electrode is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode is greater than or equal to a second tensile strength, and the tensile strength of the separator is greater than or equal to a third tensile strength.
[0009] Optionally, in some embodiments of this application, the elongation of the foil of the positive electrode is greater than or equal to 2%, and the tensile strength of the foil of the positive electrode is greater than or equal to 200 MPa.
[0010] Optionally, in some embodiments of this application, the foil of the positive electrode sheet has an elongation of 3% and a tensile strength of 200 MPa.
[0011] Optionally, in some embodiments of this application, the elongation of the foil of the negative electrode sheet is greater than or equal to 5%, and the tensile strength of the foil of the negative electrode sheet is greater than or equal to 300 MPa.
[0012] Optionally, in some embodiments of this application, the foil of the negative electrode sheet has an elongation of 10% and a tensile strength of 300 MPa.
[0013] Optionally, in some embodiments of this application, the tensile strength of the diaphragm is greater than or equal to 300 MPa.
[0014] Optionally, in some embodiments of this application, the tensile strength of the diaphragm is 400 MPa;
[0015] Optionally, in some embodiments of this application, the positive electrode and the negative electrode each have an exposed current collector at their tail ends, wherein the tail end of the outermost exposed current collector has a finishing adhesive tape, and the peeling force of the finishing adhesive tape is less than 5 N / mm.
[0016] Optionally, in some embodiments of this application, the peel force of the finishing tape is 3 N / mm.
[0017] This application provides a soft-pack battery cell structure and battery, including: a positive electrode sheet, a separator, and a negative electrode sheet stacked sequentially, wherein the positive electrode sheet, the separator, and the negative electrode sheet are wound in the same direction to form a battery cell; wherein the elongation of the foil of the positive electrode sheet is greater than or equal to a first elongation, and the tensile strength of the foil of the positive electrode sheet is greater than or equal to a first tensile strength, and / or; the elongation of the foil of the negative electrode sheet is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode sheet is greater than or equal to a second tensile strength. The soft-pack battery cell structure provided in this application has a positive electrode foil with an elongation rate greater than or equal to a first elongation rate and a tensile strength greater than or equal to a first tensile strength, and / or a negative electrode foil with an elongation rate greater than or equal to a second preset value and a tensile strength greater than or equal to a second tensile strength, and the separator with a tensile strength greater than or equal to a third tensile strength. This structure can provide a buffer against external impacts on the core, preventing foil breakage. As a result, it can safely withstand compression and heavy object impacts, thus improving battery safety. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the soft-pack battery cell structure provided in the embodiments of this application.
[0020] Diagram description: 1-Positive electrode; 2-Negative electrode; 3-Separator; 4-Finishing adhesive tape. Detailed Implementation
[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.
[0022] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.
[0023] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.
[0024] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.
[0025] The following sections provide detailed descriptions of each example. It should be noted that the order in which the embodiments are described is not intended to limit the priority of the embodiments.
[0026] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the soft-pack battery cell provided in an embodiment of this application. The soft-pack battery cell structure includes a positive electrode 1, a separator 3, and a negative electrode 2 stacked sequentially, and the positive electrode 1, the separator 3, and the negative electrode 2 are wound in the same direction to form a battery cell;
[0027] Wherein, the elongation of the foil of the positive electrode 1 is greater than or equal to the first elongation, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to the first tensile strength, and / or; the elongation of the foil of the negative electrode 2 is greater than or equal to the second preset value, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to the second tensile strength, and the tensile strength of the separator 3 is greater than or equal to the third tensile strength.
[0028] Optionally, in some embodiments of this application, the elongation of the foil of the positive electrode 1 is greater than or equal to the first elongation, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to the first tensile strength.
[0029] Optionally, in some embodiments of this application, the elongation of the foil of the negative electrode 2 is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to a second tensile strength, and the tensile strength of the separator 3 is greater than or equal to a third tensile strength.
[0030] Optionally, the elongation of the foil of the positive electrode 1 is greater than or equal to a first elongation, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to a first tensile strength; and the elongation of the foil of the negative electrode 2 is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to a second tensile strength, and the tensile strength of the separator 3 is greater than or equal to a third tensile strength.
[0031] Elongation is an important indicator of a material's mechanical properties, describing the maximum degree of deformation a material can withstand in a tensile test. It reflects a material's ability to undergo plastic deformation and is a crucial parameter for measuring its toughness. In the design of battery foils (such as positive electrode aluminum foil and negative electrode copper foil), elongation is a critical characteristic because it directly affects the battery's safety and reliability under mechanical impact.
[0032] Tensile strength refers to the maximum stress a material can withstand in a tensile test, usually measured in megapascals (MPa). It reflects the strength and toughness of a material under tensile stress.
[0033] In this embodiment, the foil of the positive electrode 1 is a thin metal sheet used to support the positive electrode active material and provide a conductive path. It is typically aluminum foil because aluminum has good conductivity, low density, and good compatibility with positive electrode materials (such as lithium iron phosphate, ternary materials, etc.). In this embodiment, the elongation of the foil of the positive electrode 1 is greater than or equal to a first elongation, meaning that the aluminum foil can stretch by at least the first elongation when subjected to external force, thereby acting as a buffer when the battery is subjected to compression or other mechanical impacts; at the same time, the tensile strength of the foil of the positive electrode 1 is greater than or equal to a first tensile strength, meaning that the aluminum foil can withstand a tensile force of at least the first tensile strength without breaking, thereby maintaining structural integrity under mechanical stress.
[0034] The foil of the negative electrode 2 is a thin metal sheet used to support the negative electrode active material and provide a conductive path. In lithium-ion batteries, copper foil is typically used for the negative electrode foil because copper has excellent conductivity, good mechanical properties, and compatibility with negative electrode materials (such as graphite, silicon carbide, etc.). In the embodiments of this application, the elongation of the foil of the negative electrode 2 is greater than or equal to a second elongation, meaning that the copper foil can elongate by at least the second elongation when subjected to external force, thereby acting as a buffer when the battery is subjected to compression or other mechanical impacts; at the same time, the tensile strength of the foil of the negative electrode 2 is greater than or equal to a second tensile strength, meaning that the copper foil can withstand a tensile force of at least the second tensile strength without breaking, thereby maintaining structural integrity under mechanical stress.
[0035] Therefore, the soft-pack battery cell structure provided in this application has a foil elongation rate greater than or equal to a first elongation rate and a foil tensile strength greater than or equal to a first tensile strength, and a foil elongation rate greater than or equal to a second preset value and a foil tensile strength greater than or equal to a second tensile strength. This structure can provide a buffer against external impacts on the core, preventing foil breakage. As a result, it can safely withstand needle penetration and heavy object impacts, thus improving battery safety.
[0036] Optionally, in some embodiments of this application, the elongation of the foil of the positive electrode 1 is greater than or equal to 2%, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to 200 MPa.
[0037] Optionally, in some embodiments of this application, the elongation of the foil of the positive electrode 1 is 3%, and the tensile strength of the foil of the positive electrode is 200 MPa.
[0038] Optionally, in some embodiments of this application, the elongation of the foil of the negative electrode 2 is greater than or equal to 5%, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to 300 MPa.
[0039] Optionally, in some embodiments of this application, the foil of the negative electrode 2 has an elongation of 10% and a tensile strength of 300 MPa.
[0040] It should be noted that in the battery, the separator 3 serves to physically isolate the positive and negative electrodes, preventing them from coming into direct contact. At the same time, the separator can maintain the structural integrity of the battery when it is subjected to external impact, preventing it from breaking or deforming. Therefore, in order to further improve the safety of the battery, in some embodiments of this application, the tensile strength of the separator is greater than or equal to 300 MPa.
[0041] Optionally, in some embodiments of this application, the tensile strength of the diaphragm 3 is greater than or equal to 400 MPa.
[0042] In addition, it should be noted that the diaphragm 3 is coated with a ceramic coating to enhance its stability at high temperatures and prevent thermal runaway.
[0043] Therefore, in the soft-pack battery cell structure provided by this application, the elongation of the foil of the positive electrode 1 is greater than or equal to the first elongation, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to the first tensile strength; the elongation of the foil of the negative electrode 2 is greater than or equal to the second preset value, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to the second tensile strength; at the same time, the tensile strength of the separator is greater than or equal to 300MPa, which can play a buffering role in resisting external impacts on the core and prevent the foil from breaking. Thus, it can safely cope with squeezing and heavy object impacts, and can improve the safety of the battery.
[0044] Please continue reading. Figure 1 The positive electrode 1 and the negative electrode 2 each have exposed current collectors at their tails. The outermost exposed current collector has a tail tape 4 at its tail, and the peeling force of the tail tape 4 is less than 5 N / mm.
[0045] The sealing tape is a key material used in the structure of pouch batteries. Its main function is to provide fixation and protection on the outside of the battery core, while releasing stress under mechanical impact to prevent damage to the internal battery structure. In the embodiments of this application, in order to improve the safety and reliability of the battery, the peel force of the sealing tape 4 is less than 5 N / mm. This is because the low viscosity design allows the tape to release stress when subjected to external impact, rather than concentrating the stress and transferring it to the internal battery structure. When the battery is subjected to compression or other mechanical impacts, the low viscosity sealing tape 4 can release stress through its own deformation or sliding, thereby protecting the foil and separator 3 inside the battery from damage.
[0046] Optionally, in some embodiments of this application, the peel force of the finishing tape 4 is 3 N / mm.
[0047] Furthermore, the following experiments will verify the impact of different material combinations on the structure of pouch cells during extrusion testing, optimize material performance, and ensure high battery safety under mechanical impact, as detailed below:
[0048] Foil:
[0049] High-elongation aluminum foil (AF1, AF2): with different elongation and tensile strength respectively.
[0050] High-elongation copper foil (CF1, CF2): with different elongation and tensile strength respectively.
[0051] Diaphragm:
[0052] S1: Tensile strength is 400MPa.
[0053] S2: Tensile strength is 300MPa.
[0054] Finishing tape:
[0055] T1: The peel force of the steel plate is 3N / mm.
[0056] T2: The peel force of the steel plate is 5 N / mm.
[0057] The experiment was divided into three stages, with optimizations made for the foil, diaphragm 3, and finishing adhesive tape 4, respectively.
[0058]
[0059] Experimental Design:
[0060] Phase 1: To investigate the impact of different foil combinations on the cell extrusion effect, two types of aluminum foil (AF1, AF2) and two types of copper foil (CF1, CF2) were carefully selected and used to prepare cell samples, which were then rigorously subjected to extrusion tests. During the tests, key parameters such as the elongation and tensile strength of the aluminum foil and the elongation and tensile strength of the copper foil were recorded in detail. Based on the test data of four different foil combinations, Scheme 1, using AF1 aluminum foil and CF1 copper foil, with AF1 aluminum foil having an elongation of 3.0% and a tensile strength of 200 MPa, and CF1 copper foil having an elongation of 10% and a tensile strength of 300 MPa, failed 4 out of 10 extrusion tests (4 / 10 NG). Scheme 2, using AF2 aluminum foil and CF1 copper foil, with AF2 aluminum foil having an elongation of 2.0% and a tensile strength of 300 MPa, failed 5 out of 10 tests (5 / 10 NG). Scheme 3, using AF1 aluminum foil and CF2 copper foil, with CF2 copper foil having an elongation of 5% and a tensile strength of 400 MPa, failed 8 out of 10 tests (8 / 10 NG). Scheme 4, using AF2 aluminum foil and CF2 copper foil, failed a high number of 9 out of 10 tests (9 / 10 NG). In summary, high-elongation foils have a significant advantage in improving extrusion performance, and Scheme 1 performs better than the other schemes. Therefore, Scheme 1 was selected for the next stage of the experiment.
[0061] Next, the diaphragm was optimized for Scheme 1, and the effect of the tensile strength of different diaphragms (S1, S2) on the extrusion effect was tested.
[0062]
[0063] Based on Scheme 1 selected in the first phase, the focus was on optimizing diaphragm 3. Two different diaphragms (S1 and S2) were tested, and their tensile strength was closely monitored for its impact on the cell extrusion effect. Scheme 5 used the S1 diaphragm, with a tensile strength of 400 MPa, and failed 2 out of 10 extrusion tests (2 / 10 NG). Scheme 6 used the S2 diaphragm, with a tensile strength of 300 MPa, and failed 4 out of 10 extrusion tests (4 / 10 NG). Comparative analysis showed that high-strength foil was more advantageous in improving the extrusion effect, and the S1 diaphragm in Scheme 5 performed better. Therefore, Scheme 5 was selected as the basis for subsequent experiments.
[0064] Finally, based on scheme 5, different adhesive films (T1, T2) were wrapped around the outside of the core, and the extrusion effect was evaluated by testing the peel force of the steel plate.
[0065]
[0066] For Scheme 5, different types of adhesive tape (T1, T2) were wrapped around the core, and their impact on the cell extrusion effect was evaluated by precisely testing the steel plate peel force. Scheme 7, using T1 adhesive tape, had a steel plate peel force of 3 N / mm and passed all 10 extrusion tests (10 / 10 OK). Scheme 8, using T2 adhesive tape, had a steel plate peel force of 5 N / mm and passed only one test (1 / 10 NG). The test results clearly show that low-tack adhesive tape significantly improves the extrusion effect, and Scheme 7's overall performance far surpasses that of Scheme 8. After multiple rounds of rigorous experiments and detailed data analysis, the materials and processes involved in Scheme 7 were ultimately selected for cell fabrication, providing a practical solution for improving cell extrusion performance.
[0067] The soft-pack battery cell structure provided in this application embodiment includes: a positive electrode 1, a separator 3, and a negative electrode 2 stacked sequentially, wherein the positive electrode 1, the separator 3, and the negative electrode 2 are wound in the same direction to form a battery cell; wherein the elongation of the foil of the positive electrode 1 is greater than or equal to a first elongation, and the tensile strength of the foil of the positive electrode 1 is greater than or equal to a first tensile strength, and / or; the elongation of the foil of the negative electrode 2 is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode 2 is greater than or equal to a second tensile strength. The soft-pack battery cell structure provided in this application has an elongation rate of the foil of the positive electrode 1 that is greater than or equal to a first elongation rate and a tensile strength of the foil of the positive electrode 1 that is greater than or equal to a first tensile strength, and / or an elongation rate of the foil of the negative electrode 2 that is greater than or equal to a second preset value and a tensile strength of the foil of the negative electrode 2 that is greater than or equal to a second tensile strength. This structure can provide a buffer against external impacts to the core, preventing the foil from breaking. As a result, it can safely withstand needle penetration and heavy object impacts, thereby improving the safety of the battery.
[0068] That is, the above description is only an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, such as the combination of technical features between different embodiments, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of this application.
[0069] Furthermore, for structural elements with the same or similar characteristics, this application may use the same or different reference numerals for identification. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.
[0070] In this application, the word "for example" is used to mean "used as an example, illustration, or explanation." Any embodiment described as "for example" in this application is not necessarily to be construed as more preferred or advantageous than other embodiments. This application has been provided above to enable any person skilled in the art to make and use it. Various details are set forth in the above description for purposes of explanation.
[0071] It should be understood that those skilled in the art will recognize that this application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.
[0072] The above provides a detailed description of a soft-pack battery cell structure provided by the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A soft-pack battery cell structure, characterized by, include: A positive electrode, a separator, and a negative electrode are stacked in sequence, and the positive electrode, the separator, and the negative electrode are wound in the same direction to form a battery cell; Wherein, the elongation of the foil of the positive electrode is greater than or equal to a first elongation, and the tensile strength of the foil of the positive electrode is greater than or equal to a first tensile strength, and / or; the elongation of the foil of the negative electrode is greater than or equal to a second preset value, and the tensile strength of the foil of the negative electrode is greater than or equal to a second tensile strength, and the tensile strength of the separator is greater than or equal to a third tensile strength.
2. The pouch cell structure of claim 1, wherein, The elongation of the foil of the positive electrode is greater than or equal to 2%, and the tensile strength of the foil of the positive electrode is greater than or equal to 200 MPa.
3. The pouch cell structure of claim 2, wherein, The foil of the positive electrode has an elongation of 3% and a tensile strength of 200 MPa.
4. The pouch cell structure of claim 1, wherein, The foil of the negative electrode sheet has an elongation of 5% or more and a tensile strength of 300 MPa or more.
5. The soft-pack battery cell structure of claim 4, wherein, The foil of the negative electrode sheet has an elongation of 10% and a tensile strength of 300 MPa.
6. The pouch cell structure of any one of claims 1 to 5, wherein, The tensile strength of the diaphragm is greater than or equal to 300 MPa.
7. The soft-pack battery cell structure of claim 6, wherein, The tensile strength of the diaphragm is greater than or equal to 400 MPa.
8. The pouch cell structure of any one of claims 1 to 5, wherein, The positive electrode and the negative electrode each have exposed current collectors at their tail ends, wherein the outermost exposed current collector has a finishing adhesive tape at its tail end, and the peeling force of the finishing adhesive tape is less than 5 N / mm.
9. The soft-pack battery cell structure of claim 8, wherein, The peel strength of the finishing adhesive tape is 3 N / mm.
10. A battery, characterized by The soft-pack battery cell structure includes any one of claims 1-9.