Pole piece structure, battery cell and secondary battery
By setting stress-bearing areas, protrusion areas, and slot areas on the electrode current collector, and combining them with the design of open areas, the wettability and stability problems of lithium-ion battery electrode structures under high winding layers and thicknesses are solved, thereby improving the charge and discharge performance and safety of the cell.
Patent Information
- Application Number
- CN202423115975.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2034-12-17
AI Technical Summary
Increasing the number of winding layers and thickness of existing lithium-ion battery electrode structures leads to a decrease in the stability and safety of the cell structure, as well as a reduction in electrode wettability and rate charge/discharge performance.
A stress-bearing area, a raised area, and a groove area are set on the current collector of the electrode, and protrusions and grooves are added in the width direction. Combined with the design of the void area, the electrode structure is optimized to improve the electrolyte flow and the containment space, thereby enhancing the wettability and stability of the electrode.
It improves the wettability and rate charge/discharge performance of the electrode, enhances the structural stability and efficiency of the cell, and avoids problems such as electrode edge damage and insufficient electrolyte.
Smart Images
Figure CN223797345U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery technology, and in particular relates to an electrode structure, a battery cell and a secondary battery. Background Technology
[0002] Currently, countries around the world are vigorously developing green energy. Lithium-ion batteries, with their high energy density, long cycle life, and environmental friendliness, have become the main power source for consumer electronics and electric vehicles. As society continues to develop, people are placing increasingly higher demands on the capacity of lithium-ion batteries. The number of winding layers in the battery cell is increasing, and the thickness of the positive and negative electrode plates is also growing. This reduces the cell's rate charge / discharge performance and increases the risk of lithium plating during cycling; at the same time, making electrolyte wetting of the electrode plates a challenge.
[0003] Currently, most methods for improving rate performance and electrode wettability primarily rely on electrode embossing technology. Electrode embossing creates textured patterns on the electrode through opposing extrusion, producing electrolyte reservoir grooves to improve kinetic performance and address electrolyte wetting issues and rate charge / discharge performance. However, embossed electrode edges are prone to breakage and cracking, thus reducing the structural stability and safety of the electrode structure and the battery cell. Therefore, existing methods for improving rate performance and electrode wettability reduce cell structural stability and safety, and also affect the cell's rate charge / discharge performance. Utility Model Content
[0004] The purpose of this invention is to provide an electrode structure that addresses the shortcomings of existing technologies and solves the technical problems of low stability and safety in the cell structure of existing technologies.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] An electrode structure includes a current collector and an active material layer connected to at least one side of the current collector;
[0007] Along the length of the current collector, the active material layer has at least two stress-bearing regions; the active material layer also has an air-relief region; the air-relief region is located between two adjacent stress-bearing regions.
[0008] In the width direction of the current collector, the force-bearing area is provided with a raised area and a groove area; and the raised area is provided with at least one protrusion; the groove area is provided with at least one groove.
[0009] Preferably, there are two groove areas, and the groove areas are arranged on the upper and lower sides of the protrusion area along the width direction of the collector; and the side of the groove away from the protrusion area extends toward the edge of the collector.
[0010] Preferably, the width D of one of the slot areas 22 The width D of the other slot area 23 The relationship between the width D2 of the stressed region and the given width satisfies: D 22 +D 23 =D2*(5%~70%);
[0011] And / or, the width D of the protrusion region 201 21 The relationship between the width D2 of the force-bearing region 2 and the given width D2 satisfies: D 21 =D2*(30%~95%).
[0012] Preferably, the distance S2 between the groove near the edge of the current collector and the edge of the current collector satisfies: 0 < S2 ≤ 15 mm;
[0013] And / or, the distance between the groove near the edge of the raised area and the protrusion near the edge of the slot area is S1, where S1 satisfies: 0 < S1 ≤ 5 mm.
[0014] Preferably, the relationship between the width D2 of the force-bearing region and the width D1 of the current collector satisfies: D2 = D1 * (50% ~ 100%);
[0015] And / or, the relationship between the sum of the lengths of all the stress-bearing regions L1 and the length of the current collector L0 satisfies: L1 = L0 * (30% ~ 90%).
[0016] Preferably, the clearance area includes a tab assembly partition; the tab assembly partition is disposed between two adjacent stress areas.
[0017] Preferably, the clearance area further includes at least one blank area; the blank area and the tab assembly partition are arranged along the length direction of the current collector; the blank area is arranged between two adjacent stress areas and / or between the stress area and the edge of the current collector;
[0018] The relationship between the sum of the lengths of all the blank areas L2 and the length of the current collector L0 satisfies: L2 = L0 * (10% ~ 70%); and / or the number of blank areas M1 satisfies: M1 ≥ 1.
[0019] Preferably, the clearance area further includes at least one protective adhesive mounting partition; the protective adhesive mounting partition and the tab assembly partition are arranged along the length direction of the current collector; the protective adhesive mounting partition is located between two adjacent stress-bearing areas;
[0020] The number of protective adhesive installation zones, M2, satisfies the following condition: 4 ≥ M2 ≥ 1.
[0021] This utility model also discloses a battery cell, including the electrode structure described above.
[0022] This utility model also discloses a secondary battery, including the aforementioned battery cell.
[0023] The beneficial effects of this utility model are as follows: By adding several protrusions in the raised area and several grooves in the slot area along the width direction of the force-bearing area, the flow space and containment space of the electrolyte can be increased, thereby improving the wettability of the electrode and enhancing the rate charge and discharge performance of the battery cell; thus improving the efficiency and stability of use; In addition, by simultaneously providing protrusions in the raised area and grooves in the slot area, a certain space is reserved for the expansion of the electrode during the cycle, improving the rebound of the battery cell's cycle thickness, thereby improving the efficiency and stability of use; Furthermore, by adding a void area, the conductivity of the electrode structure is prevented from being affected by pressure or laser etching, thereby improving the efficiency and stability of use. Attached Figure Description
[0024] The following will refer to the appendix. Figures 1-4 This section describes the features, advantages, and technical effects of exemplary embodiments of the present invention.
[0025] Figure 1 This is a schematic diagram of the electrode structure according to an embodiment of the present invention;
[0026] Figure 2 This is a partially enlarged view of the electrode structure according to an embodiment of the present invention;
[0027] Figure 3 This is a schematic diagram of the electrode structure according to an embodiment of the present invention;
[0028] Figure 4 This is a partially enlarged view of the electrode structure according to an embodiment of the present invention.
[0029] In the diagram: 11-Current collector; 12-Active material layer; 2-Stress area; 21-Protrusion; 22-Groove; 201-Raised area; 202-Groove area; 3-Void area; 31-Electrode assembly zone; 311-Electrode groove; 312-Electrode body; 32-Protective adhesive installation zone; 321-Green adhesive; 4-White space. Detailed Implementation
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0031] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0033] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or multiple situations existing alone. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.
[0034] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0035] The following is in conjunction with the appendix Figures 1-4 The present invention will be described in further detail, but this is not intended to limit the scope of the present invention.
[0036] like Figure 1 and 2 As shown, in one embodiment of the present invention, the electrode structure includes a current collector 11 and an active material layer 12 connected to at least one side of the current collector 11.
[0037] Along the length of the current collector 11, the active material layer 12 is provided with at least two stress-bearing regions 2; the active material layer 12 is also provided with an air-avoiding region 3; the air-avoiding region 3 is disposed between two adjacent stress-bearing regions 2;
[0038] In the width direction of the current collector 11, the force-bearing area 2 is provided with a protrusion area 201 and a groove area 202; and the protrusion area 201 is provided with at least one protrusion 21; the groove area 202 is provided with at least one groove 22.
[0039] The technical solution of this utility model improves the flow space and containment space of the electrolyte by adding several protrusions in the raised area and several grooves in the slot area along the width direction of the force-bearing area, thereby improving the wettability of the electrode and enhancing the rate charge and discharge performance of the battery cell; thus improving the efficiency and stability. Furthermore, by simultaneously providing protrusions in the raised area and grooves in the slot area, a certain space is reserved for the expansion of the electrode during the cycle, improving the rebound of the battery cell's cycle thickness, thereby improving the efficiency and stability. In addition, by adding a void area, the conductivity of the electrode structure is prevented from being affected by pressure or laser etching, thereby improving the efficiency and stability.
[0040] The current collector 11 includes a first surface perpendicular to the electrode thickness direction and a second surface opposite to the first surface. The first surface has a raised area 201, and the second surface has a recessed area. The protrusions 21 of the raised area 201 contact the separator, providing support for the separator. When the electrode body expands, the protrusions 21 can still support the separator, so that there is space between the separator and the protrusions 21 to accommodate the electrolyte, preventing abnormalities such as insufficient electrolyte or poor wetting between the electrode structure and the separator due to expansion and compression.
[0041] Specifically, in some implementations, such as Figure 1 and 2 As shown, in the width direction of the current collector 11, there are two slot areas 202, respectively located on the upper and lower sides of the raised area 201; and the side of the groove 22 away from the raised area 201 extends towards the edge of the current collector 11. This structure reduces the difficulty of dust removal during etching and improves the K-value of the battery cell by providing slot areas only on the upper and lower sides of the raised area; it also avoids electrode breakage and cracking caused by embossing the edge of the current collector, thereby improving efficiency and stability. In addition, the protrusions in the raised area and the grooves in the slot areas provide a certain space for electrode expansion during the cycling process, improving the cycling thickness rebound of the battery cell, thereby improving efficiency and stability. In some embodiments, such as Figure 2 As shown, the width D of the raised area 201 21 The width D of slot area 20222 The width D of another slot area 202 23 The relationship between D and the width D2 of the force-bearing region 2 satisfies: D 22 +D 23 =D2*(5%~70%); and / or, D 21 =D²*(30%~95%). Where D can be... 22 +D 23 =D2*5%, D 22 +D 23 =D2*30%, D 22 +D 23 =D2*50%, D 22 +D 23 =D2*70% etc.; D 21 =D2*30%; D 21 =D2*50%; D 21 =D2*70; D 21 =D2*95%, etc. In other words, the groove 22 and the protrusion 21 respectively fill the interior of the stress area, so that the effect of improving the electrode wetting and rate charge and discharge performance is better; thereby improving the rate charge and discharge performance of the battery cell; and thus improving the efficiency and stability of use.
[0042] Specifically, in some implementations, such as Figure 1 and 2 As shown, grooves 22 are arranged side-by-side along the length of the current collector 11; and the grooves 22 can be a long rectangular strip, a dotted rectangular strip, a rhombus, or other shapes or combinations thereof. Protrusions 21 are arranged in an array along the length of the current collector 11; and the protrusions 21 can be dot-shaped, rhomboid, or other shapes or combinations thereof. That is, the grooves 22 and protrusions 21 can be installed simultaneously or in any order (the function of the electrode will not be affected by different process sequences); thus, a certain space is reserved for electrode expansion during the cycling process, improving the cell's cycling thickness rebound, thereby improving efficiency and stability.
[0043] Specifically, in some implementations, such as Figure 1 and 2 As shown in Figure 4, the distance S2 between the groove 22 near the edge of the current collector 11 and the edge of the current collector 11 satisfies: 0 < S2 ≤ 15 mm; S2 can be 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, 15 mm, etc.; preferably 1 mm. This structure, with a groove 22 of a certain appropriate value, can avoid etching through the side end of the current collector and cause damage, and can also ensure improved electrode wetting and rate charge / discharge performance.
[0044] Specifically, in some implementations, such as Figure 1 and2 As shown in Figure 4, the distance between the groove 22 near the edge of the raised area 201 and the protrusion 21 near the edge of the slot area 202 is S1, where S1 satisfies: 0 < S1 ≤ 5 mm; S2 can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.; preferably 1 mm. This structure, through the groove 22 and protrusion 21 in a suitable position, can ensure improved electrode wettability and rate charge / discharge performance.
[0045] Specifically, in some implementations, such as Figure 2 and 3 As shown, the relationship between the width D2 of the force-bearing region 2 and the width D1 of the current collector 11 satisfies: D2 = D1 * (50% ~ 100%). This can be: D2 = D1 * 50%, D2 = D1 * 60%, D2 = D1 * 70%, D2 = D1 * 80%, etc. Furthermore, the larger the proportion of the width of the force-bearing region 2, the better the improvement effect on electrode wetting and rate charge / discharge performance; thus improving the rate charge / discharge performance of the battery cell; and consequently improving its efficiency and stability.
[0046] Specifically, in some implementations, such as Figure 2 and 3 As shown, the relationship between the sum of the lengths of all stress-bearing regions 2 (the length of the protrusion region 201 or the length of the slot region 202) L1 and the length L0 of the current collector 11 satisfies: L1 = L0 * (30% ~ 90%). Specifically, L1 can be L0 * 30%; L1 = L0 * 40%; or L1 = L0 * 50%; L1 = L0 * 80%; L1 = L0 * 90%, etc. Furthermore, the larger the proportion of the length of the stress-bearing region 2, the better the improvement effect on electrode wetting and rate charge / discharge performance; thereby improving the rate charge / discharge performance of the battery cell; and further improving its efficiency and stability.
[0047] Specifically, in some of these implementations, such as Figure 1 and 3As shown, the clearance area 3 includes a tab assembly section 31, at least one protective adhesive installation section 32, and at least one blank area 4, arranged along the length of the current collector 11. The tab assembly section 31 is located between two adjacent stress areas 2. The protective adhesive installation section 32 is located between two adjacent stress areas 2. The tab assembly section 31 has a tab groove 311. The tab groove 311 has a tab body 312. The tab body 312 is connected to the current collector 11. The protective adhesive installation section 32 has green adhesive 321. The blank area 4 is located between two adjacent stress areas 2 and / or between the stress area 2 and the edge of the current collector 11. The blank area 4 consists only of the current collector 11 and the active material layer 12 connected to both sides of the current collector 11. The number of blank areas 4, M1, satisfies: M1≥1. The number of protective adhesive installation sections 32, M2, satisfies: 4≥M2≥1. This structure ensures the installation stability of the tab body 312 and guarantees the conductivity of the electrode structure by using tab assembly partitions 31, protective adhesive installation partitions 32, and blank areas 4 and stress areas 2 arranged in any combination and alternating along the length of the current collector 11 along the length of the electrode sheet. In some embodiments, (not shown in the figure) the blank area 3 includes tab assembly partitions 31 and at least one protective adhesive installation partition 32 arranged along the length of the current collector 11; the tab assembly partition 31 is located between two adjacent stress areas 2; the protective adhesive installation partition 32 is located between two adjacent stress areas 2; the tab assembly partition 31 has a tab groove 311; the tab groove 311 has a tab body 312; and the tab body 312 is connected to the current collector 11; the protective adhesive installation partition 32 has green adhesive 321. In some other embodiments, (not shown in the figure) the clearance area 3 includes an electrode assembly partition 31 arranged along the length of the current collector 11 and at least one blank area 4; the electrode assembly partition 31 is disposed between two adjacent force-bearing areas 2; the electrode assembly partition 31 is provided with an electrode groove 311; the electrode groove 311 is provided with an electrode body 312; and the electrode body 312 is connected to the current collector 11; the blank area 4 is disposed between two adjacent force-bearing areas 2 and / or between the edge of the force-bearing area 2 and the current collector 11; the blank area 4 is only the current collector 11 and the active material layer 12 connected to the two side surfaces of the current collector 11.
[0048] Specifically, in some implementations, such as Figure 1 and 3As shown, the relationship between the sum of the lengths L2 of all blank areas 4 and the length L0 of the current collector 11 satisfies: L2 = L0 * (10% ~ 70%); where L2 = L0 * (10% ~ 60%); further, it can be L2 = L0 * 10%, L2 = L0 * 20%, L2 = L0 * 30%, L2 = L0 * 40%, L2 = L0 * 50%, L2 = L0 * 60%, etc. In some embodiments, the relationship between the length L3 of the tab assembly section 31, the length L4 of all protective adhesive installation sections 32, and the length L0 of the current collector 11 satisfies: L3 + L4 =
[0049] L0*10%. This structure, through a certain proportion of tab assembly partitions 31, can prevent the tabs from being affected by pressure or laser etching, thus avoiding impact on conductivity; through a certain proportion of protective adhesive installation partitions, it can prevent the adhesive paper from falling off under pressure or losing its protective effect after being melted by laser etching.
[0050] This utility model also proposes a battery cell, which includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode; the positive electrode and / or the negative electrode are electrode structures, and the specific structure of the electrode structure is as described in the above embodiments. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.
[0051] The positive electrode includes a positive current collector and a positive active material layer, with the active material layer coated on the surface of the current collector. The current collector can be made of aluminum, and the active material layer includes the active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer, with the active material layer coated on the surface of the current collector. The current collector can be made of copper, and the active material layer includes the active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.
[0052] This utility model also proposes a secondary battery, which includes a battery cell. The specific structure of the battery cell is as described in the above embodiments. Since this secondary battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.
[0053] A rechargeable battery, also known as a secondary battery or accumulator battery, is a battery that can be recharged after discharge to reactivate its active materials and continue to be used. Utilizing the reversibility of chemical reactions, a new battery can be constructed; that is, after a chemical reaction converts into electrical energy, the electrical energy can be used to repair the chemical system, and then the chemical reaction can be converted back into electrical energy. Therefore, it is called a secondary battery (rechargeable battery). The main types of rechargeable batteries on the market include nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid (or lead-acid) batteries, lithium-ion batteries, and polymer lithium-ion batteries.
[0054] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0055] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on this utility model are within the protection scope of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.
Claims
1. An electrode structure, characterized in that: It includes a current collector and an active material layer connected to at least one side of the current collector; Along the length of the current collector, the active material layer has at least two stress-bearing regions; the active material layer also has an air-relief region; the air-relief region is located between two adjacent stress-bearing regions. In the width direction of the current collector, the force-bearing area is provided with a raised area and a groove area; and the raised area is provided with at least one protrusion; the groove area is provided with at least one groove.
2. The electrode structure according to claim 1, characterized in that: The number of groove areas is two, and the groove areas are arranged on the upper and lower sides of the protrusion area along the width direction of the collector; and the side of the groove away from the protrusion area extends toward the edge of the collector.
3. The electrode structure according to claim 2, characterized in that: The width D of the slot area mentioned above 22 The width D of the other slot area 23 The relationship between the width D2 of the stressed region and the given width satisfies: D 22 +D 23 =D2*(5%~70%); And / or, the width D of the protrusion area 21 The relationship between the width D2 of the stressed region and the given width satisfies: D 21 =D2*(30%~95%).
4. The electrode structure according to claim 1, 2, or 3, characterized in that: The distance S2 between the groove near the edge of the current collector and the edge of the current collector satisfies: 0 < S2 ≤ 15 mm; And / or, the distance between the groove near the edge of the raised area and the protrusion near the edge of the slot area is S1, where S1 satisfies: 0 < S1 ≤ 5 mm.
5. The electrode structure according to claim 1, 2, or 3, characterized in that: The relationship between the width D2 of the force-bearing region and the width D1 of the current collector satisfies: D2 = D1 * (50% ~ 100%). And / or, the relationship between the sum of the lengths of all the stress-bearing regions L1 and the length of the current collector L0 satisfies: L1 = L0 * (30% ~ 90%).
6. The electrode structure according to claim 1, 2, or 3, characterized in that: The clearance zone includes a tab assembly section; the tab assembly section is located between two adjacent stress zones.
7. The electrode structure according to claim 6, characterized in that: The clearance area also includes at least one blank area; the blank area and the electrode assembly partition are arranged along the length direction of the current collector; the blank area is arranged between two adjacent force-bearing areas and / or between the force-bearing area and the edge of the current collector; The relationship between the sum of the lengths of all the blank areas L2 and the length of the current collector L0 satisfies: L2 = L0 * (10% ~ 70%); and / or the number of blank areas M1 satisfies: M1 ≥ 1.
8. The electrode structure according to claim 6, characterized in that: The clearance area also includes at least one protective adhesive installation zone; the protective adhesive installation zone and the tab assembly zone are arranged along the length direction of the current collector; the protective adhesive installation zone is arranged between two adjacent stress zones; The number of protective adhesive installation zones, M2, satisfies the following condition: 4 ≥ M2 ≥ 1.
9. A battery cell, characterized in that: Includes the electrode structure described in any one of claims 1 to 8.
10. A secondary battery, characterized in that: Includes the battery cell described in claim 9.