Battery cell pole piece structure, battery cell and battery
By using the current collector with raised and concave structures in the lithium-ion cell electrode sheet, the problem of insufficient adhesion between the active layer and the current collector is solved, the assembly stability and cycling performance are improved, the cost is reduced and the use of the electrode is enhanced Security.
Patent Information
- Application Number
- CN202322470910.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-12
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2033-09-12
AI Technical Summary
During the drying and de-embedding process of the existing lithium-ion cell electrode sheet, the adhesion between the active layer and the current collector becomes worse, resulting in material layering or powder loss, which in turn affects the internal shortening and cycling performance of the cell.
The current collector with a concave structure formed by the projection and the main connecting body is adopted to increase the contact interface area between the active material layer and the current collector, improve assembly stability, and enhance the structural stability of the current collector through the concave-convex surface design.
The adhesion between the active material layer and the current collector is improved, separation and fracture phenomenon is avoided, costs are reduced, and the cyclic performance and structural stability of the electrode are improved.
Smart Images
Figure CN222190780U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of battery cores, and in particular relates to a battery core pole piece structure, a battery core and a battery. Background Art
[0002] The current lithium-ion battery cell contains positive and negative electrodes, electrolyte and protective shell. The positive and negative electrodes are respectively composed of active materials and current collectors. The current collector is responsible for connecting the circuit between the inside and the outside, and is also responsible for anchoring the electrode active materials and ensuring fast and stable transmission of electrons.
[0003] In most planar battery cell pole pieces, the active layer (solid layer derived from the electrode slurry liquid) is generally applied flat on the metal foil current collector. However, the shrinkage stress of the electrode slurry increases during the drying process and the lithium extraction process, and the adhesion between the active layer and the current collector becomes poor, which can easily cause the active material to delaminate or fall off, leading to hidden dangers such as internal short circuits and reduced cycle performance of the battery cell. Utility Model Content
[0004] The purpose of the utility model is to provide a battery core pole piece structure to improve the assembly stability between the current collector and the active material layer in view of the deficiencies in the prior art.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A battery cell pole piece structure, comprising:
[0007] A current collector, the current collector comprising a main connector and a protrusion disposed on at least one side end surface of the main connector; the number of the protrusions is at least two, and a depression is formed between two adjacent protrusions and the main connector;
[0008] and an active material layer, wherein the active material layer is respectively connected to the protrusion, the depression and the main connector.
[0009] Preferably, the main connecting body is provided with a first connecting surface and a second connecting surface which are arranged opposite to each other; the number of the protrusions is at least four, and they are respectively arranged on the first connecting surface and the second connecting surface;
[0010] Wherein, the protrusion arranged on the first connecting surface and the protrusion arranged on the second connecting surface are arranged symmetrically.
[0011] Preferably, the protrusion is provided with an outer end surface, and the outer end surface is arranged opposite to the first connecting surface; and the outer end surfaces of all the protrusions are arranged horizontally with each other.
[0012] Preferably, the relationship between the total coverage area S1 of the orthographic projections of all the protrusions on the main connector and the coverage area S2 of the orthographic projections of the main connector is S1=S2*A, wherein A is 40% to 60%.
[0013] Preferably, the relationship between the width W1 of the protrusion and the width W2 of the recess satisfies: W1=W2*B, wherein B is 1% to 50%.
[0014] Preferably, the relationship between the height L1 of the protrusion and the total height L2 of the current collector satisfies: L1 = L2*C, wherein C is 1% to 45%.
[0015] Preferably, the relationship between the height L1 of the protrusion and the height L3 of the main connector satisfies: L1=L3*D, wherein D is 40% to 100%.
[0016] Preferably, the protrusion is a block with a rectangular or square cross section;
[0017] And / or, a guide arc surface is provided at a side end of the protrusion, and the guide arc surfaces of two adjacent protrusions and the main connecting body form the recess.
[0018] The utility model also discloses a battery core, comprising the battery core pole piece structure.
[0019] The utility model also discloses a battery, comprising the battery core.
[0020] The beneficial effect of the utility model lies in that the technical scheme adopts protrusions and depressions formed by the protrusions and the main connector to form a current collector with alternating concave and convex surfaces, which can increase the area of the contact interface between the active material layer and the current collector, thereby improving the assembly stability of the current collector to the active material layer, and can also avoid the separation of the active material layer from the current collector during thermal stress and deintercalation, thereby improving the adhesion between the active material layer and the current collector, and can eliminate the primer design, and can also reduce costs and improve the cycle performance of the electrode; in addition, the structural stability of the current collector is improved by using the current collector with alternating concave and convex surfaces, avoiding the phenomenon of current collector breakage, which is beneficial to improving the cycle performance of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The following will refer to the attached Figures 1 to 4 To describe the features, advantages and technical effects of exemplary embodiments of the present utility model.
[0022] Figure 1 This is a schematic structural diagram of a battery cell electrode structure according to one embodiment of the utility model;
[0023] Figure 2This is a schematic structural diagram of a current collector according to an embodiment of the utility model;
[0024] Figure 3 This is a schematic structural diagram of a current collector according to an embodiment of the utility model;
[0025] Figure 4 It is a structural schematic diagram of a battery cell electrode structure according to another embodiment of the utility model.
[0026] In the figure: 1 - current collector; 11 - main connector; 111 - first connecting surface; 112 - second connecting surface; 113 - outer end surface; 12 - protrusion; 14 - guide arc surface; 2 - active material layer; 3 - depression. DETAILED DESCRIPTION
[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.
[0028] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.
[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0030] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship between the related objects of the description of the cell pole piece structure, the cell and the battery, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and multiple situations exist alone. In addition, the character " / " in this article generally indicates that the previous and next related objects are an "or" relationship between a cell pole piece structure, a cell and a battery.
[0031] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).
[0032] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.
[0033] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0034] The following is combined with Figure 1 to Figure 4 The utility model is further described in detail, but it is not intended to limit the utility model.
[0035] like Figure 1 and 2 As shown, in one embodiment of the utility model, the battery cell pole piece structure includes a current collector 1 and an active material layer 2; the current collector 1 includes a main connector 11 and a protrusion 12 disposed on at least one side end face of the main connector 11, the protrusion 12 is disposed protruding from the current collector 1 toward the outside; and the number of the protrusions 12 is at least two, and a recess 3 is formed between two adjacent protrusions 12 and the main connector 11; the active material layer 2 is respectively connected to the protrusion 12, the recess 3 and the main connector 11. Among them, the side end faces are the upper and lower surface end faces.
[0036] The technical solution of the utility model adopts protrusions and depressions formed by the protrusions and the main connector to form a current collector with alternating concave and convex surfaces, which can increase the area of the contact interface between the active material layer and the current collector, thereby improving the assembly stability between the current collector and the active material layer, and can also avoid the separation of the active material layer from the current collector during thermal stress and deintercalation, thereby improving the adhesion between the active material layer and the current collector, and can eliminate the primer design, avoid the occurrence of stratification or powder loss, and can also reduce costs and improve the cycle performance of the electrode; in addition, the current collector with alternating concave and convex surfaces can improve the structural stability of the current collector, avoid the occurrence of breakage of the current collector, which is beneficial to improving the cycle performance of the electrode.
[0037] Among them, in some embodiments, the battery cell pole piece structure is a positive electrode piece; the current collector 1 is an aluminum foil; and the active material layer 2 is made of a slurry containing lithium ions. In other embodiments, the battery cell pole piece structure is a negative electrode piece, the current collector 1 is a copper foil, and the active material layer 2 is made of a slurry such as graphite, silicon, silicon oxide, or graphite mixed with silicon. The current collector 1 of the negative electrode piece can be made into a concave morphology by passing through a specific morphology roller and repeatedly heat-treated and rolled; it can also be made by electrolysis, that is, in a special dissolution container and the electrolyte is electrodeposited under the action of direct current, and then surface treated. The current collector 1 of the positive electrode piece is made by passing through a specific morphology roller and repeatedly heat-treated and rolled.
[0038] Specifically, in some embodiments, Figure 2 and Figure 3 As shown, the main connector 11 is provided with a first connecting surface 111 and a second connecting surface 112 which are arranged opposite to each other; the number of protrusions 12 is at least four, and they are respectively arranged on the first connecting surface 111 and the second connecting surface 112. By respectively adding protrusions 12 on both sides of the main connector 11, the area of the contact interface on both sides of the main connector 11 can be increased, and the amount of electron transmission can be further increased and the rate of electron transmission can be improved; thus, it is beneficial to improve the cycle performance of the electrode.
[0039] Wherein, in some embodiments, Figure 3 As shown, the protrusions 12 arranged on the first connection surface 11 are symmetrically arranged with the protrusions 12 arranged on the second connection surface 112. The symmetrically arranged protrusions 12 at both ends can ensure the speed and orderliness of electron flow, which is beneficial to improving the cycle performance and safety of the electrode.
[0040] Specifically, in some embodiments, Figure 2As shown, on one side of the first connection surface 111 or on one side of the second connection surface 112; the protrusion 12 is provided with an outer end surface 113, and the outer end surface 113 is arranged opposite to the first connection surface 111; and the outer end surfaces 113 of all protrusions 12 are arranged horizontally. Figure 2 As shown, the outer end faces 113 of all protrusions 12 on the first connection surface 111 remain horizontal along the X-axis direction, thereby ensuring that the active material layer 2 disposed on one side of the first connection surface 111 also remains horizontal during assembly, thereby improving the surface flatness of the pole piece structure, which is beneficial to improving the cycle performance and safety of use of the electrode. Alternatively, the outer end faces 113 of all protrusions 12 on the second connection surface 112 remain horizontal along the X-axis direction, thereby ensuring that the active material layer 2 disposed on one side of the second connection surface 112 also remains horizontal during assembly, thereby improving the surface flatness of the pole piece structure, which is beneficial to improving the cycle performance and safety of use of the electrode.
[0041] Specifically, in some embodiments, the relationship between the orthographic projection coverage area S1 of all protrusions 12 on the main connector 11 and the total orthographic projection coverage area S2 of the main connector 11 satisfies: S1 = S2*A, and the value range of A is 40% to 60%. Preferably, S1 = S2*50%. In other words, the installation area of the protrusions 12 occupies 50% of the surface area of the main connector 11; thereby effectively ensuring the structural firmness of the current collector 1 itself, and also ensuring the stability of the assembly of the active material layer and the amount and rate of electrons passing through the protrusions; thereby helping to improve the cycle performance of the electrode and the safety of use.
[0042] Specifically, in some embodiments, Figure 2 As shown, the relationship between the width W1 of the protrusion 12 and the width W2 of the recess 3 satisfies: W1 = W2*B. Wherein, the value range of B is 1% to 50%. Preferably, W1 = 50% W2. By alternately arranging smaller protrusions 12 and larger recesses 3, the active material layer 2 can be applied as much as possible between the protrusion 11 and the main connector 12, thereby increasing the contact interface area between the active material layer 2 and the current collector 1, thereby improving the assembly stability between the active material layer 2 and the current collector 1, avoiding their separation, and helping to improve the cycle performance of the electrode. Wherein, as Figure 2 As shown, the width direction is the X-axis direction.
[0043] Specifically, in some embodiments, Figure 2As shown, the relationship between the height L1 of the protrusion 12 on one side of the main connector 11 and the total height L2 of the current collector 1 satisfies: L1 = L2 * C. Among them, the value range of C is 1% to 45%. Preferably, it is: L1 = 33% * L2. This structure can ensure the assembly adhesion of the active material layer 2 through the protrusion of reasonable specification value; it can also ensure the assembly stability of the battery cell formed by winding the battery cell pole sheet structure or other methods, thereby improving the stability and safety of use.
[0044] Specifically, in some embodiments, Figure 2 As shown, the relationship between the height L1 of the protrusion 12 on one side of the main connector 11 and the height L3 of the main connector 11 satisfies: L1 = L3 * D. Wherein, the value range of D is 40% to 100%. Preferably, L1 = L3. When the protrusion is set on one side of the main connector 11, the assembly adhesion of the active material layer 2 can be guaranteed by the protrusion with a reasonable specification value; it can also ensure the assembly stability of the battery cell formed by winding the battery cell pole sheet structure or other methods, thereby improving the stability and safety of use.
[0045] Among them, Figure 2 As shown, the height direction is the Z-axis direction.
[0046] Specifically, in some embodiments, the protrusion 12 is a block with a rectangular or square cross section. Figure 4 As shown, the side end of the protrusion 12 is provided with a guide arc surface 14, and the guide arc surfaces 14 of two adjacent protrusions 12 and the main connector 11 form the recess 3. In some embodiments, one side end of the guide arc surfaces 14 of two adjacent protrusions 12 is connected, and the guide arc surfaces 14 of two adjacent protrusions 12 and the main connector 11 form the recess 3. The guide arc surface 14 is set in an arc shape from the protrusion 12 to the outside. This structure can ensure that the material of the active material layer 2 can be assembled into the recess 3 as quickly as possible through the guide arc surface 14, thereby improving the assembly stability between the active material layer 2 and the current collector 1, and further improving the use safety of the pole piece structure.
[0047] The utility model also proposes a battery cell, which includes a battery cell pole piece structure and an isolation membrane. The specific structure of the battery cell pole piece structure refers to the above-mentioned embodiment. Since the battery cell adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.
[0048] The battery cell pole piece structure includes a cathode piece and an anode piece; the separator is arranged between the cathode piece and the anode piece. Furthermore, the cathode piece, the separator and the anode piece are wound to form a winding core structure.
[0049] The utility model also proposes a battery, which includes a battery cell. The specific structure of the battery cell refers to the above embodiments. Since the battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.
[0050] Among them, battery refers to a cup, trough or other container or part of a composite container that contains electrolyte solution and metal electrodes to generate current, and is a device that can convert chemical energy into electrical energy; the battery has positive and negative electrodes. With the advancement of science and technology, batteries generally refer to small devices that can generate electrical energy, such as solar cells. The performance parameters of batteries mainly include electromotive force, capacity, specific energy and resistance. Battery principle: In chemical batteries, the direct conversion of chemical energy into electrical energy is the result of spontaneous oxidation, reduction and other chemical reactions inside the battery, which are carried out on the two electrodes respectively. The negative electrode active material is composed of a reducing agent with a relatively negative potential and stable in the electrolyte, such as active metals such as zinc, cadmium, and lead, and hydrogen or hydrocarbons. The positive electrode active material is composed of an oxidizing agent with a relatively positive potential and stable in the electrolyte, such as metal oxides such as manganese dioxide, lead dioxide, and nickel oxide, oxygen or air, halogens and their salts, oxygen-containing acids and their salts, etc. The electrolyte is a material with good ionic conductivity, such as an aqueous solution of acid, alkali, or salt, an organic or inorganic non-aqueous solution, a molten salt, or a solid electrolyte.
[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
[0052] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.
Claims
1. A battery cell pole piece structure, characterized in that: include: A current collector, the current collector comprising a main connector and a protrusion disposed on at least one side end surface of the main connector; The number of the protrusions is at least two, and a depression is formed between two adjacent protrusions and the main connecting body; and an active material layer, wherein the active material layer is respectively connected to the protrusion, the depression and the main connector.
2. The battery cell electrode structure according to claim 1, characterized in that: The main connecting body is provided with a first connecting surface and a second connecting surface which are arranged opposite to each other; the number of the protrusions is at least four, and they are arranged on the first connecting surface and the second connecting surface respectively; Wherein, the protrusion arranged on the first connecting surface and the protrusion arranged on the second connecting surface are arranged symmetrically.
3. The battery cell electrode structure according to claim 2, characterized in that: The protrusions are provided with outer end surfaces, which are arranged opposite to the first connecting surface; and the outer end surfaces of all the protrusions are arranged horizontally with each other.
4. The battery cell electrode structure according to claim 1, characterized in that: The relationship between the total coverage area S1 of the orthographic projection of all the protrusions on the main connector and the coverage area S2 of the orthographic projection of the main connector satisfies: S1= S2*A, where A is 40% to 60%.
5. The battery cell electrode structure according to claim 1, characterized in that: The relationship between the width W1 of the protrusion and the width W2 of the depression satisfies: W1= W2*B, wherein B is 1% to 50%.
6. The battery cell electrode structure according to claim 1, characterized in that: The relationship between the height L1 of the protrusion and the total height L2 of the current collector satisfies: L1= L2* C, where C is 1% to 45%.
7. The battery cell electrode structure according to claim 1, characterized in that: The relationship between the height L1 of the protrusion and the height L3 of the main connecting body satisfies: L1=L3*D, wherein D is 40% to 100%.
8. The battery cell electrode structure according to claim 1, characterized in that: The protrusion is a block with a rectangular cross section; And / or, a guide arc surface is provided at a side end of the protrusion, and the guide arc surfaces of two adjacent protrusions and the main connecting body form the recess.
9. A battery cell, characterized in that: The invention comprises the battery cell electrode structure as described in any one of claims 1 to 8.
10. A battery, characterized in that: Comprising the battery cell as claimed in claim 9.