Composite current collector, pole piece, battery cell and secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a composite current collector, a pole piece, a battery cell and a secondary battery. Wherein the composite current collector comprises a first conductive layer, a base material and a second conductive layer which are sequentially stacked; a conductive connection layer is arranged between the first conductive layer and the second conductive layer; the top of the conductive connection layer is connected to the first conductive layer; the bottom of the conductive connection layer is connected to the second conductive layer; the conductive connection layer and the base material are arranged adjacently. According to the utility model, the conduction of the upper and lower conductive layers of the composite current collector can be realized, so that the active substances on the AB surfaces of the battery cell can be normally de-intercalated with lithium ions.

Description

TECHNICAL FIELD

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

[0002] As indispensable key material of lithium ion battery, current collector plays the role of bearing positive and negative materials and collecting, transmitting electron. Traditional current collector not only has high preparation cost, in addition, its tensile resistance is poor, and large size burr is easily generated, and it can pierce diaphragm, and it can cause safety accident by mixing positive and negative solution. Therefore, traditional current collector cannot meet the increasing demand of people. Composite current collector is composed of multiple layers, and it becomes the most potential new current collector material of lithium ion battery due to its good conductivity and low preparation cost.

[0003] The existing composite current collector adopts the structure of metal-polymer-metal, and the middle is a polymer, and both sides are plated with a certain thickness of conductive metal layer. But in the use process of this current collector, there are some problems: the middle polymer layer of the current collector is completely insulating and non-conductive, so the conductivity is reduced. UTILITY MODEL CONTENT

[0004] The utility model aims at: in view of the deficiency of prior art, provide a kind of composite current collector, can solve the technical problem of low conductivity of prior art.

[0005] In order to realize the above-mentioned purpose, the utility model adopts the following technical scheme:

[0006] A kind of composite current collector, first conductive layer, base material and second conductive layer are sequentially stacked;Conductive link layer is provided between the first conductive layer and the second conductive layer;And the top of the conductive link layer is connected to the first conductive layer;The bottom of the conductive link layer is connected to second conductive layer;The conductive link layer is adjacent to the base material.

[0007] Preferably, the number of the conductive link layer is at least one, and the conductive link layer is connected to the side surface of the base material.

[0008] Preferably, in the width direction of the same position in the composite current collector, the relationship between the width L1 of the first conductive layer or the second conductive layer, the sum L2 of the width of all the conductive link layers and the width L3 of the base material 1 satisfies: L2+L3≤L1.

[0009] Preferably, at least one mounting groove is provided on the side surface of the base material towards the conductive link layer;The mounting groove is recessed from the direction of the conductive link layer towards the base material;The conductive link layer is connected to the mounting groove.

[0010] Preferably, the conductive connecting layer comprises conductive connecting segments and limiting connecting segments which are connected to each other; the limiting connecting segments are connected to the mounting grooves; the upper and lower ends of the conductive connecting segments are connected to the first conductive layer and the second conductive layer respectively.

[0011] Preferably, a connecting adhesive is arranged between the conductive connecting layer and the base material.

[0012] Preferably, a conductive adhesive is arranged between the conductive connecting layer and the first conductive layer and / or between the conductive connecting layer and the second conductive layer.

[0013] Preferably, the base material is one of polyacrylamide, polyvinyl chloride and polyethylene terephthalate.

[0014] Preferably, the first conductive layer is a copper conductive material or an aluminum conductive material.

[0015] Preferably, the second conductive layer is a copper conductive material or an aluminum conductive material.

[0016] Preferably, the conductive connecting layer is a copper conductive material or an aluminum conductive material.

[0017] The utility model discloses a kind of pole piece, including pole piece current collector and the active material layer of at least one surface of pole piece current collector, which is the composite current collector described above.

[0018] The utility model discloses a kind of electric core, positive pole piece and negative pole piece and the isolation film of being arranged between positive pole piece and negative pole piece, positive pole piece and / or negative pole piece are the pole piece described above.

[0019] The utility model discloses a kind of secondary batteries, including the electric core described above.

[0020] The utility model has the advantages that the conductive connecting layer is arranged between the first conductive layer and the second conductive layer, to realize the conductive communication of the first conductive layer and the second conductive layer, so that the active substance on the surface of the electric core AB can normally de-embed lithium ions, and the conductive performance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] 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

[0022] Figure 1 ​Structure schematic view of the composite current collector of one embodiment of the present utility model;

[0023] Figure 2 Structure schematic view of the composite current collector of one embodiment of the present utility model;

[0024] Figure 3 Structure schematic view of the composite current collector of one embodiment of the present utility model;

[0025] Figure 4 Structure schematic view of the composite current collector of one embodiment of the present utility model.

[0026] In the figure: 1 - base material;11 - installation groove;2 - first conductive layer;3 - second conductive layer;4 - conductive connection layer;41 - conductive connection section;42 - limit connection section;5 - connecting adhesive;6 - conductive adhesive. DETAILED DESCRIPTION

[0027] 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 in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application; the use herein of terms such as "comprise", "comprises" and "comprising" or "have", "has" and "having" and any variations thereof are to be construed as not excluding the presence of other elements or features.

[0028] In the description of the embodiments of the present 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 present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0029] 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 appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of the present 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 can mean: A exists alone, A and B exist together, and multiple cases exist alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.

[0031] 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.

[0032] 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.

[0033] like Figure 1 As shown, in one embodiment of this utility model, the composite current collector includes a first conductive layer 2, a substrate 1, and a second conductive layer 3 stacked sequentially; a conductive connecting layer 4 is provided between the first conductive layer 2 and the second conductive layer 3; one surface of the conductive connecting layer 4 is connected to the first conductive layer 2; the other surface of the conductive connecting layer 4 is connected to the second conductive layer 3; and the conductive connecting layer 4 is disposed adjacent to the substrate 1.

[0034] The technical solution of this utility model achieves conductive connection between the first conductive layer and the second conductive layer through a conductive connecting layer between the upper and lower layers; thereby enabling the active material on the AB side of the battery cell to normally insert and extract lithium ions and improve conductivity; in addition, the conductive connecting layer is arranged adjacent to the substrate, with the first conductive layer and the second conductive layer located at the upper and lower ends of the conductive connecting layer, to ensure the stability of the overall structure and guarantee the normal insertion and extraction of lithium ions from the active material.

[0035] Specifically, in some embodiments, the substrate 1 can be one of polyacrylamide (PAM), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Polyacrylamide (PAM) can improve chemical stability. Polyvinyl chloride (PVC) has good mechanical properties and chemical stability. Polyethylene terephthalate (PET) also has good mechanical properties and chemical stability. The first conductive layer 2 can be a copper conductive material (Cu) or an aluminum conductive material (Al); the second conductive layer 3 can also be a copper conductive material (Cu) or an aluminum conductive material (Al). Because copper conductive materials (Cu) or aluminum conductive materials (Al) have high conductivity, they can improve the conductivity of the composite material, thereby ensuring the cycle performance of the electrode and the battery cell.

[0036] Specifically, in some embodiments, the conductive adapter layer 4 can be a copper conductive material (Cu) or an aluminum conductive material (Al). The conductive adapter layer 4 with the same or similar material as the first conductive layer 2 or the second conductive layer 3 can further improve the conductivity efficiency of the composite current collector and improve the circulation performance of conductive ions.

[0037] Specifically, in some embodiments, as shown in Figure 1 , the number of conductive adapter layers 4 is one, and one side surface of the substrate 1 in the length direction is provided with the conductive adapter layer 4. In other embodiments, as shown in Figure 2 , the number of conductive adapter layers 4 is two, and the two side surfaces of the substrate 1 in the length direction are provided with the conductive adapter layers 4. In the length direction of the substrate 1, any one or all of the left and right side surfaces of the substrate 1 are provided with the conductive adapter layer 4, and the upper and lower side ends of the conductive adapter layer 4 are connected to the first conductive layer 2 and the second conductive layer 3, respectively, to realize the conductive communication between the first conductive layer 2 and the second conductive layer 3, realize the upper and lower layer conduction of the composite current collector, and also ensure the overall structural stability and safety in use.

[0038] Specifically, in some embodiments, as shown in Figure 2 , in the width direction of the same position in the composite current collector, the relationship between the width L1 of the first conductive layer 2 or the second conductive layer 3, the sum L2 of the widths of all conductive adapter layers 4, and the width L3 of the substrate 1 satisfies: L2+L3≤L1. Preferably, L2+L3=L1. That is, the first conductive layer 2 or the second conductive layer 3 on the upper and lower sides can cover the conductive adapter layer 4 to ensure the flatness of the pole piece formed by the composite current collector and the overall structure of the battery cell.

[0039] Specifically, in some embodiments, as shown in Figure 2 , in the width direction of the same position in the composite current collector, the relationship between the sum L2 of the widths of all conductive adapter layers 4 and the width L3 of the substrate 1 satisfies: L3 / 5≤L2≤L3 / 3. This structure can ensure the smoothness of the conductive adapter through the conductive adapter layer 4 with a certain suitable size, and can ensure the orderly implementation of the support performance of the substrate 1.

[0040] Specifically, in some embodiments, as shown in Figure 2 , at least one mounting groove 11 is provided on one side surface of the substrate 1 facing the conductive adapter layer 4; the mounting groove 11 is recessed from the direction of the conductive adapter layer 4 facing the substrate 1; and the conductive adapter layer 4 is connected to the mounting groove 11. In some embodiments, as shown in Figure 2As shown, the conductive connecting layer 4 comprises conductive connecting segments 41 and limiting connecting segments 42 which are connected to each other at an inclination; the limiting connecting segments 42 are connected to the mounting groove 11; the upper and lower ends of the conductive connecting segments 41 are connected to the first conductive layer 2 and the second conductive layer 3 respectively. Further, the conductive connecting segments 41 and the limiting connecting segments 42 are arranged vertically to form a T-shaped structure. This structure further improves the assembly stability of the conductive connecting layer 4 through the mounting groove 11 and the T-shaped structure formed by the conductive connecting segments 41 and the limiting connecting segments 42, so as to ensure the smoothness of the conductive connection and the orderly implementation of the supporting performance of the base material 1.

[0041] Specifically, in some embodiments, as shown in Figs. 1-4, a connecting adhesive 5 is arranged between the conductive connecting layer 4 and the base material 1; and a conductive adhesive 6 is arranged between the conductive connecting layer 4 and the first conductive layer 2 and between the conductive connecting layer 4 and the second conductive layer 3. The connecting adhesive 5 is selected from an epoxy resin-based conductive adhesive or a polyimide resin-based conductive adhesive; and the conductive adhesive 6 is selected from an epoxy resin-based conductive adhesive, a carbon-based conductive adhesive or a polyimide resin-based conductive adhesive. This structure can improve the stability of the adhesion and also ensure the overall conductivity. Figure 2 3 Specifically, in some embodiments, as shown in Figs. 1-4, a connecting adhesive 5 is arranged between the conductive connecting layer 4 and the base material 1; and a conductive adhesive 6 is arranged between the conductive connecting layer 4 and the first conductive layer 2 and between the conductive connecting layer 4 and the second conductive layer 3. The connecting adhesive 5 is selected from an epoxy resin-based conductive adhesive or a polyimide resin-based conductive adhesive; and the conductive adhesive 6 is selected from an epoxy resin-based conductive adhesive, a carbon-based conductive adhesive or a polyimide resin-based conductive adhesive. This structure can improve the stability of the adhesion and also ensure the overall conductivity.

[0042] The utility model discloses still propose a kind of pole piece, the active material layer of at least one surface of the pole piece current collector is arranged, the specific structure of the pole piece current collector refers to above-mentioned embodiment, since the pole piece of the present application adopts all technical solutions of above-mentioned all embodiments, at least have all beneficial effects brought by the technical solution of above-mentioned embodiment, here no longer one by one elaboration.

[0043] The utility model discloses still propose a kind of electric core, the electric core includes positive pole piece and negative pole piece and the isolation film being arranged between positive pole piece and negative pole piece, and positive pole piece and negative pole piece are above-mentioned pole piece;The specific structure of the pole piece refers to above-mentioned embodiment, since the electric core of the present application adopts all technical solutions of above-mentioned all embodiments, at least have all beneficial effects brought by the technical solution of above-mentioned embodiment, here no longer one by one elaboration.

[0044] The positive pole piece includes positive pole current collector and positive pole active material layer, and the positive pole active material layer is coated on the surface of the positive pole current collector. The material of the positive pole current collector can be aluminum. The positive pole active material layer includes positive pole active material, which can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative pole piece includes negative pole current collector and negative pole active material layer, and the negative pole active material layer is coated on the surface of the negative pole current collector. The material of the negative pole current collector can be copper. The negative pole active material layer includes negative pole active material, which can be carbon or silicon, etc. The material of the isolation member can be PP (polypropylene) or PE (polyethylene), etc.​

[0045] The utility model discloses still a kind of secondary battery, the secondary battery includes battery core, the specific structure of the battery core refers to above-mentioned embodiment, since the secondary battery of the present application adopts all technical solutions of above-mentioned all embodiments, at least has all beneficial effects brought by the technical scheme of above-mentioned embodiment, here no longer one by one elaboration.

[0046] Among them, secondary battery (Rechargeab l e battery) is also called as rechargeable battery or battery, is to refer to the battery that active material is activated and continues to use by the way of charging after battery discharge.Utilize the reversibility of chemical reaction, can be built into a new battery, i.e.when a chemical reaction is converted into electric energy, chemical system can be repaired by electric energy, and then chemical reaction is converted into electric energy, so called secondary battery (rechargeable battery).Market mainly rechargeable battery has nickel-hydrogen battery, nickel-cadmium battery, lead-acid (or lead storage) battery, lithium ion battery, polymer lithium ion battery etc.

[0047] In addition, it should be understood that, although the present specification is described according to the embodiment, not every embodiment contains only one independent technical scheme, the description manner of the specification is only for the sake of clarity, the skilled in the art should be the whole specification, the technical scheme in each embodiment can also be combined appropriately, form other embodiments that the skilled in the art can understand.

[0048] According to the disclosure and teaching of the above description, the skilled in the art of the utility model can also change and modify the above-mentioned embodiment. Therefore, the utility model is not limited to the above-mentioned specific embodiment, any obvious improvement, replacement or modification made by the skilled in the art 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 the present specification, these terms are only for the convenience of description, and do not constitute any limitation on the utility model.

Claims

1. A composite current collector, characterized by: The composite current collector comprises a first conductive layer, a substrate and a second conductive layer which are sequentially stacked; a conductive connecting layer is arranged between the first conductive layer and the second conductive layer; the top of the conductive connecting layer is connected to the first conductive layer; the bottom of the conductive connecting layer is connected to the second conductive layer; and the conductive connecting layer is arranged adjacent to the substrate.

2. The composite current collector of claim 1, wherein: The number of the conductive connecting layers is at least one, and the conductive connecting layers are connected to the side surface of the substrate.

3. The composite current collector of claim 1, wherein: In the width direction of the same position in the composite current collector, the relationship among the width L1 of the first conductive layer or the second conductive layer, the sum L2 of the widths of all the conductive connecting layers, and the width L3 of the substrate (1) satisfies: L2+L3≤L1.

4. The composite current collector of claim 1, wherein: At least one mounting groove is arranged on the side surface of the substrate facing the conductive connecting layer; the mounting groove is recessed from the direction of the conductive connecting layer to the substrate; and the conductive connecting layer is connected to the mounting groove.

5. The composite current collector of claim 4, wherein: The conductive connecting layer comprises a conductive connecting section and a limiting connecting section which are connected to each other at an inclination; the limiting connecting section is connected to the mounting groove; and the upper and lower ends of the conductive connecting section are respectively connected to the first conductive layer and the second conductive layer.

6. The composite current collector of claim 1, wherein: A connecting adhesive is arranged between the conductive connecting layer and the substrate; And / or, a conductive adhesive is arranged between the conductive connecting layer and the first conductive layer and / or between the conductive connecting layer and the second conductive layer.

7. The composite current collector of claim 1, wherein: The substrate is one of polyacrylamide, polyvinyl chloride and polyethylene terephthalate; And / or, the first conductive layer is a copper conductive material or an aluminum conductive material; And / or, the second conductive layer is a copper conductive material or an aluminum conductive material; And / or, the conductive connecting layer is a copper conductive material or an aluminum conductive material.

8. A pole piece characterized by: The electrode sheet current collector comprises an electrode sheet current collector and an active material layer arranged on at least one surface of the electrode sheet current collector, and the electrode sheet current collector is the composite current collector according to any one of claims 1 to 7.

9. An electric cell characterized by: The positive electrode sheet and the negative electrode sheet and the separator arranged between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet and / or the negative electrode sheet is the electrode sheet according to claim 8.

10. A secondary battery characterized by comprising: The battery cell comprises the battery cell according to claim 9.

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