Battery cell pole piece, battery cell and secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell pole piece, a battery cell and a secondary battery. The battery cell pole piece comprises a heat conduction structure, a tab body, a current collector and an active material layer connected to at least one surface of the current collector, a tab groove is formed in the active material layer; the tab groove extends to the surface of one side of the current collector; the tab body is connected to the current collector in the tab groove; the heat conduction structure is arranged on the current collector at the tab groove; and in the thickness direction of the current collector, the heat conduction structure penetrates through the current collector. According to the utility model, thermal pressure generated by thermal expansion can be reduced; therefore, stress concentration is effectively relieved, the reliability of the current collector is improved, and the service life of the cell is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model belongs to battery technical field especially relates to a kind of electric core pole piece, electric core and secondary battery. BACKGROUND

[0002] After the commercial application of lithium ion battery, it has been widely used in portable consumer electronics and electric vehicles due to its high energy density and power density. With the increasing demand for the endurance of electronic products and electric vehicles, the requirement for energy density of lithium ion battery is also increasing. During the welding and hot pressing of the tab, excessive temperature can cause excessive expansion of the tab material, and shrinkage after cooling can generate a large stress; excessive pressure can also directly act on the tab, causing excessive strain inside the tab and forming a large stress, which can cause tab deformation and cracking, affecting the connection stability of the tab with the current collector, and increasing the internal resistance of the battery. And in the process of charging and discharging, it causes the internal heat of the battery to increase, affecting the efficiency of the battery. At the same time, it can cause the local temperature of the battery to be too high, which poses a safety hazard, such as causing the battery to short circuit, thermal runaway, and even causing fire, explosion and other serious consequences.

[0003] However, the current common solution is to use better heat dissipation materials to optimize the tab structure. However, this method has high cost and poor heat dissipation effect for internal heat, and the ability to buffer the hot pressure is also poor, which cannot ensure the stability of the overall use. UTILITY MODEL CONTENT

[0004] The utility model aims at the deficiencies of the prior art, and provides an electric core pole piece that can solve the poor heat dissipation effect of the prior art.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0006] An electric core pole piece includes a heat-conducting structure, a tab body, a current collector and an active material layer connected to at least one surface of the current collector; the active material layer is provided with a tab slot; the tab slot extends to one side surface of the current collector; the tab body is connected to the current collector in the tab slot; the heat-conducting structure is provided on the current collector at the tab slot; in the thickness direction of the current collector, the heat-conducting structure penetrates the current collector.

[0007] Preferably, the distance between two adjacent heat-conducting structures is d, and the d satisfies: 0.5mm≤d≤2mm.

[0008] Preferably, the heat-conducting structure is a first heat-conducting channel; the first heat-conducting channel is arranged between the active material layer and the tab body.

[0009] Preferably, the relationship between the depth h1 of the first heat-conducting channel and the thickness h2 of the current collector satisfies: 1pm≤h1=h2≤10pm.

[0010] Preferably, the distance between the first heat-conducting channel and the active material layer in the length direction and / or the width direction of the current collector is L1, satisfying: 0.5mm≤L1≤1.5mm.

[0011] Preferably, the distance between the first heat-conducting channel and the tab body in the length direction and / or the width direction of the current collector is L2, satisfying: 1.0mm≤L2≤3.0mm.

[0012] Preferably, the heat-conducting structure is a second heat-conducting channel; a projection of the second heat-conducting channel in the thickness direction of the current collector at least partially overlaps the tab body.

[0013] Preferably, the relationship between the depth h3 of the second heat-conducting channel and the thickness h2 of the current collector satisfies: 1pm≤h3=h2≤18pm.

[0014] The utility model discloses still a kind of battery, including the battery pole piece of above-mentioned.

[0015] The utility model discloses still a kind of secondary battery, including the battery of above-mentioned.

[0016] The utility model has the advantages that the heat generated by the heat-conducting structure to the current collector and the tab body is discharged, so that the heat dissipation is accelerated, the local temperature of the tab body and the current collector is reduced, the thermal stress caused by thermal expansion is reduced, the stress concentration is effectively alleviated, the reliability of the current collector is improved, and the service life of the battery is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0017] The features, advantages and technical effects of the exemplary embodiments of the utility model will be described below with reference to the accompanying drawings. Figures 1-4

[0018] Figure 1 It is the structure schematic view of battery pole piece of an embodiment of the utility model;

[0019] Figure 2 It is the sectional view of battery pole piece of an embodiment of the utility model;

[0020] Figure 3 It is the structure schematic view of battery pole piece of another embodiment of the utility model;

[0021] Figure 4 ​The utility model discloses another embodiment's sectional view of the electrode tab of the battery cell.

[0022] In the drawing: 1-collector; 11-blank area; 2-active material layer; 21-tab slot; 3-tab body; 4-heat conduction structure; 41-first heat conduction channel; 42-second heat conduction channel. DETAILED DESCRIPTION

[0023] 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 belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application; the use of the terms "including," "comprising," "having" and "with" in the specification and claims and the aforementioned description of embodiments of the application with respect to what is meant by "including" and "comprising" and their equivalents shall also be construed as open-ended, not excluding additional, unrecited elements or method steps.

[0024] In the description of the embodiments of the application, the technical terms "first", "second" and the like 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 application, the meaning of "multiple" is more than two, unless otherwise explicitly and specifically limited.

[0025] 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 application. The occurrence of the phrase in various places in the specification is not necessarily all referring to the same embodiment, nor is it necessarily referring to a separate or alternative embodiment to the other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with each other.

[0026] In the description of the embodiments of the application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and multiple cases exist alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0027] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanical connection, or it can be electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0028] The following will be described in detailFigures 1-4 The utility model makes further detailed description, but not as the limitation of the utility model.

[0029] As Figure 1 The utility model discloses an electrode tab body, the electrode tab body includes the heat conduction structure 4, the electrode tab body 3, the current collector 1 and the active material layer 2 connected to the surface of current collector 1 at least, is equipped with the tab slot 21 on the active material layer 2, the tab slot 21 extends to the one side surface of current collector 1 setting, the electrode tab body 3 is connected to the current collector 1 in the tab slot 21, the heat conduction structure 4 is set up in the current collector 1 of tab slot 21 place, in the thickness direction of the current collector 1, the heat conduction structure 4 penetrates the current collector 1.

[0030] The utility model discloses a technical scheme, and the heat generated by the heat conduction structure to the current collector and the electrode tab is conducted and is discharged, so that the heat dissipation can be accelerated, the local temperature of the electrode tab and the current collector is reduced, the thermal stress generated by thermal expansion is reduced, the excessive deformation of the electrode tab can be avoided, the stress concentration is effectively relieved, the reliability of the current collector is improved, and the service life of the battery cell is prolonged.

[0031] Specifically, in some embodiments, as Figure 1 The distance between the two adjacent heat conduction structures 4 is d, and the d satisfies: 0.5mm≤d≤2mm. Wherein, d can be 0.5μm, 1μm, 1.5μm, 2μm, etc. Preferably, d=2μm. The structure can improve the speed of heat dissipation by suitable spacing of the heat conduction structure 4, and ensure the support stress of the structure of the current collector, avoid damage to the current collector.

[0032] Specifically, in some embodiments, as Figure 1 And 2 The heat conduction structure 4 is a first heat conduction channel 41; the first heat conduction channel 41 penetrates the thickness of the current collector 1 and is arranged between the active material layer 2 and the electrode tab 3. That is, the projection of the electrode tab 3 towards the current collector 1 is arranged in a staggered manner with the first heat conduction channel 41. That is, the first heat conduction channel 41 is arranged on the inner edge of the electrode tab slot of the electrode tab welding slot, so as to accelerate the heat dissipation, thereby reducing the local temperature of the electrode tab and reducing the thermal stress generated by thermal expansion. At the same time, the first heat conduction channel 41 can also play a buffering role, when the electrode tab is heated and expanded, part of the pressure can be released through the through hole, avoiding excessive deformation of the electrode tab; thereby improving the reliability of the current collector 1 and the service life of the battery cell. In addition, the first heat conduction channel 41 can also play a role of limiting and positioning the welding position of the electrode tab, so as to facilitate accurate welding of the electrode tab to the current collector, thereby improving the production efficiency.

[0033] Specifically, in some embodiments, as shown in Figure 2 The relationship between the depth h1 of the first heat conduction channel 41 and the thickness h2 of the current collector 1 satisfies: 1 μm≤h1=h2≤10 μm. Wherein, h1 can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, etc. Preferably, 2 μm. That is, when the first heat conduction channel 41 is arranged in the inner edge of the tab slot of the tab welding groove, the first heat conduction channel 41 is processed according to the thickness of the current collector, so as to improve the speed of heat dissipation, effectively alleviate stress concentration, and improve the reliability of the current collector 1 and the service life of the battery cell.

[0034] Wherein, in some embodiments, the shape of the first heat conduction channel 41 can be circular, V-shaped or other suitable shape; and the number of the first heat conduction channel 41 is adjusted according to the actual processing needs. Further, the inner width M1 of the first heat conduction channel 41 satisfies: 70 μm≤M1≤90 μm; can be 70 μm, 75 μm, 80 μm, 85 μm, 88 μm, 90 μm, etc.; preferably 80 μm.

[0035] Specifically, in some embodiments, as shown in Figure 2 In the length direction and / or width direction of the current collector 1, the distance between the first heat conduction channel 41 and the active material layer 2 is L1, which satisfies: 0.5 mm≤L1≤1.5 mm; wherein, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc. can be selected; preferably 1.0 mm. That is, the first heat conduction channel 41 is uniformly distributed at a distance of 1.0 mm from the edge of the tab slot 21, so as to ensure that the hot-pressing stress can be effectively reduced without affecting the structural strength of the tab slot 21. Wherein, in the length direction and / or width direction of the current collector 1, the distance between the first heat conduction channel 41 and the tab body 3 is L2, which satisfies: 1.0 mm≤L2≤3.0 mm; wherein, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, etc. can be selected; preferably 2.0 mm. That is, the first heat conduction channel 41 is uniformly distributed at a distance of 2.0 mm from the edge of the tab slot 21, so as to ensure that the hot-pressing stress can be effectively reduced without affecting the assembly strength of the tab body 3.

[0036] Specifically, in some embodiments, as shown in Figure 1 and 2As shown, a blank area 11 is provided between the tab body 3 and the active material layer 2; and the relationship between the coverage area S1 of all the first heat-conducting channels 41 and the area S2 of the blank area 11 satisfies: S1 = (50%~75%)*S2. The structure can ensure the reduction of the thermal stress by means of the appropriate coverage area of the first heat-conducting channels 41, without affecting the assembly strength of the tab body 3; thereby improving the reliability of the current collector and prolonging the service life of the battery cell.

[0037] Specifically, in some embodiments, as shown in Figure 3 As shown, the heat-conducting structure 4 is a second heat-conducting channel 42; the second heat-conducting channel 42 is arranged through the thickness of the current collector 1; the projection of the second heat-conducting channel 42 in the thickness direction of the current collector 1 at least partially overlaps with the tab body 3 (i.e. the projection of the second heat-conducting channel 42 towards the tab body 3 is at least partially overlapped with the tab body 3). In some embodiments, the second heat-conducting channel 42 is completely arranged at the bottom of the tab body 3. In another part of the embodiments, part of the structure of the second heat-conducting channel 42 is arranged at the bottom of the tab body 3. Therefore, the second heat-conducting channel 42 arranged directly at the bottom of the tab body 3 can accelerate the heat dissipation, thereby reducing the local temperature of the tab body and reducing the thermal stress caused by thermal expansion. At the same time, the second heat-conducting channel 42 can also play a buffering role, when the tab body is expanded by heat, part of the pressure can be released through the through hole, avoiding excessive deformation of the tab; thereby improving the reliability of the current collector 1 and the service life of the battery cell.

[0038] Specifically, in some embodiments, as shown in Figure 3 and 4 As shown, the relationship between the depth h3 of the second heat-conducting channel 41 and the thickness h2 of the current collector 1 satisfies: 1 μm≤h3=h2≤18 μm. Wherein, h3 can be 1 μm, 2 μm, 3 μm, 8 μm, 18 μm, etc. Preferably, 8 μm. That is, when the second heat-conducting channel 42 is arranged below the tab body, the second heat-conducting channel 42 is processed according to the thickness of the current collector, thereby improving the speed of heat dissipation, effectively relieving stress concentration, and improving the reliability of the current collector 1 and the service life of the battery cell.

[0039] Wherein, in some embodiments, the shape of the second heat-conducting channel 42 can be circular, V-shaped or other suitable shape; and the number of the second heat-conducting channels 42 is adjusted according to the actual processing requirements. Further, the inner width M2 of the second heat-conducting channel 42 satisfies: 70 μm≤M2≤90 μm; which can be 70 μm, 75 μm, 80 μm, 85 μm, 88 μm, 90 μm, etc.; preferably, 80 μm.

[0040] The utility model discloses still propose a kind of electric core, the electric core includes electric core pole piece, the specific structure of the electric core pole piece refers to above-mentioned embodiment, since the electric core adopts all technical solutions of above-mentioned all embodiments, therefore at least have all beneficial effects brought by the technical scheme of above-mentioned embodiment, here no longer one by one elaboration.

[0041] The electric core includes a positive pole piece, a negative pole piece and a separator. The positive pole piece includes a positive current collector and a positive active material layer, and the positive active material layer is coated on the surface of the positive current collector. The positive current collector includes a positive coating area and a positive tab connected to the positive coating area. The material of the positive current collector can be aluminum. The positive active material layer includes a positive active material, which can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative pole piece includes a negative current collector and a negative active material layer, and the negative active material layer is coated on the surface of the negative current collector. The negative current collector includes a negative coating area and a negative tab connected to the negative coating area. The material of the negative current collector can be copper. The negative active material layer includes a negative active material, which can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0042] The utility model discloses still propose a kind of secondary battery, the specific structure of the electric core of the secondary battery refers to above-mentioned embodiment, since the secondary battery adopts all technical solutions of above-mentioned all embodiments, therefore at least have all beneficial effects brought by the technical scheme of above-mentioned embodiment, here no longer one by one elaboration.

[0043] The secondary battery (Rechargeable battery) is also called a rechargeable battery or a storage battery. It refers to a battery that can be activated by charging after discharging and continue to be used. By using the reversibility of chemical reaction, a new battery can be formed, that is, after a chemical reaction is converted into electric energy, the chemical system can be repaired by using electric energy, and then the chemical reaction is converted into electric energy, so it is called a secondary battery (rechargeable battery). The main rechargeable batteries on the market include nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid (or lead-acid) batteries, lithium-ion batteries, polymer lithium-ion batteries, etc. The most common secondary battery is a lead-acid battery, which is composed of two groups of grid-shaped plates arranged alternately. The positive plate is covered with PbO2, and the negative plate is covered with Pb. The electrolyte is H2SO4 solution.

[0044] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and the skilled in the art should understand 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.

[0045] According to the disclosure and teaching of the above description, those skilled in the art of the present application can also make changes and modifications to the above embodiments. Therefore, the present application is not limited to the above specific embodiments, and any obvious improvements, replacements or modifications made by those skilled in the art on the basis of the present application all belong to the protection scope of the present application. In addition, although some specific terms are used in the present specification, these terms are only for the convenience of description and do not constitute any limitation on the present application.

Claims

1. A battery cell electrode, characterized in that: It includes a thermally conductive structure, an electrode body, a current collector, and an active material layer connected to at least one surface of the current collector; the active material layer is provided with an electrode groove; the electrode groove extends to one side surface of the current collector; The tab body is connected to the current collector within the tab groove; the heat-conducting structure is disposed on the current collector at the tab groove; The thermally conductive structure extends through the current collector in the thickness direction of the current collector.

2. The cell electrode sheet according to claim 1, characterized in that: Multiple heat-conducting structures are provided, and the distance between two adjacent heat-conducting structures is d, wherein d satisfies: 0.5mm≤d≤2mm.

3. The cell electrode sheet according to claim 1 or 2, characterized in that: The thermally conductive structure is a first thermally conductive channel; the first thermally conductive channel is disposed between the active material layer and the tab body.

4. The cell electrode sheet according to claim 3, characterized in that: The relationship between the depth h1 of the first heat conduction channel and the thickness h2 of the current collector satisfies: 1μm≤h1=h2≤10μm.

5. The cell electrode sheet according to claim 3, characterized in that: The distance between the first heat-conducting channel and the active material layer in the length and / or width directions of the current collector is L1, which satisfies: 0.5mm≤L1≤1.5mm.

6. The cell electrode sheet according to claim 3, characterized in that: The distance between the first heat-conducting channel and the tab body in the length and / or width directions of the current collector is L2, which satisfies: 1.0mm≤L2≤3.0mm.

7. The cell electrode sheet according to claim 1 or 2, characterized in that: The heat-conducting structure is a second heat-conducting channel; the projection of the second heat-conducting channel in the thickness direction of the current collector at least partially overlaps with the tab body.

8. The cell electrode sheet according to claim 7, characterized in that: The relationship between the depth h3 of the second heat conduction channel and the thickness h2 of the current collector satisfies: 1μm≤h3=h2≤18μm.

9. A battery cell, characterized in that: Includes the cell electrode sheet as described in any one of claims 1 to 8.

10. A secondary battery, characterized in that: Includes the battery cell described in claim 9.

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