TW202046539A - Collector for lithium battery and electrode structure for lithium battery - Google Patents

Abstract

A collector for lithium battery and an electrode structure for lithium battery are provided. The collector for lithium battery includes a plastic substrate and two metal layers. The plastic substrate has two opposite surfaces. The two metal layers are respectively disposed on the two opposite surfaces of the plastic substrate and are connected with each other via a conductive structure. The electrode structure for lithium battery includes the collector and two electrode materials. The two electrode materials are respectively formed on the two metal layers of the collector.

Description

Current collector and electrode structure for lithium battery

The present invention relates to a current collector and electrode structure, in particular to a current collector and electrode structure for lithium batteries.

With the advancement of technology, the functions of electronic products have gradually diversified, but it has also resulted in electronic products requiring higher power to maintain their operational functions. In order to provide sufficient power, the selection of batteries is even more important. Compared with other rechargeable batteries, lithium batteries are widely used because of their high capacity and high voltage characteristics.

In actual use, the power that a single lithium battery can provide is limited. Therefore, in some high power consumption electronic products, multiple lithium batteries are connected in parallel to form a battery pack. However, as a result, the volume of the battery pack will be quite huge and the weight will also increase, on the contrary, it will affect the convenience of carrying electronic products, which goes against the goal of thinning electronic products. Therefore, in order to take into account the high capacity of the battery pack and the lightness and thinness of electronic products, in the prior art, efforts are made to reduce the size and weight of lithium batteries to maintain the advantages of lightness and thinness of electronic products.

The technical problem to be solved by the present invention is to provide a current collector and electrode structure for a lithium battery in view of the shortcomings of the prior art.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a current collector for lithium batteries. The current collector for a lithium battery includes a plastic substrate and two metal layers. The two metal layers are respectively disposed on two opposite surfaces of the plastic substrate, and the two metal layers are electrically connected to each other.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide an electrode structure for lithium batteries. The electrode structure for lithium batteries includes a current collector and two electrode materials. The current collector includes a plastic substrate and two metal layers. The two metal layers are respectively disposed on two opposite surfaces of the plastic substrate, and the two metal layers are electrically connected to each other. The two electrode materials are respectively formed on the two metal layers of the current collector.

One of the beneficial effects of the present invention is that the current collector and electrode structure for lithium batteries provided by the present invention can pass the technical features of "plastic substrate" and "two metal layers electrically connected to each other", So that the current collector of the present invention can replace the existing metal current collector, and has a lighter weight and a smaller volume, in response to the trend of thinner and lighter electronic products.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings about the present invention. However, the provided drawings are only for reference and description, and are not used to limit the present invention.

The following are specific examples to illustrate the implementation of the “current collector and electrode structure for lithium batteries” disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. . The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are merely schematic illustrations, and are not drawn according to actual dimensions, and are stated in advance. The following embodiments will further describe the related technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention.

It should be understood that the term "or" used in this document may include any one or a combination of more of the associated listed items depending on the actual situation.

First, please refer to Figure 1 and Figure 2. FIG. 1 is a three-dimensional schematic diagram of a lithium battery, and FIG. 2 is a side sectional view of the internal structure of the lithium battery. Specifically, the lithium battery in FIG. 1 is formed by winding the positive electrode 1, the separator 2 and the negative electrode 3. The positive electrode 1 and the negative electrode 3 in the lithium battery are arranged at intervals, and a separator 2 is provided between each positive electrode 1 and the negative electrode 3. The isolation film 2 is an insulating material, and the arrangement of the isolation film 2 can prevent the positive electrode 1 and the negative electrode 3 from contacting each other in the wound state, and avoid the short circuit of the positive electrode 1 and the negative electrode 3 due to the electrical connection. In addition, the rolled positive electrode 1, the separator 2 and the negative electrode 3 are covered and packaged with an insulator 4 to isolate them from the outside world. The insulator 4 is filled with electrolyte to help ion transfer and maintain charge balance.

For convenience of description, the positive electrode 1 and the negative electrode 3 are collectively referred to as electrode structures below. According to FIG. 2, the electrode structure (positive electrode 1 or negative electrode 3) includes a current collector C and an electrode material 5 arranged on the current collector C. When the lithium battery is charged and discharged, the current collector C can be used as a conductor of electrons, and the electrode material 5 can provide lithium ions participating in the reaction. In this embodiment, the current collector C of the positive electrode 1 is aluminum foil, and the current collector C of the negative electrode 3 is copper foil, but the current collector C can be selected from other conductive materials according to the required electrical characteristics. The manufacturing method of the electrode structure is to first uniformly coat the electrode material 5 on the current collector C, then dry the electrode material 5, and then make the electrode material 5 and the current collector C tightly contact by rolling. However, the above steps are only one of the feasible embodiments and are not intended to limit the present invention.

In order to make the capacity of the lithium battery meet expectations, and not affect the light and thin characteristics of electronic products. The current collector C and the electrode structure of the lithium battery of the present invention can not only have a lower volume and weight to meet the requirements of light and thin electronic products, but also have resistance characteristics that are not inferior to that of commercially available metal current collectors. Directly replace commercially available metal current collectors.

Please refer to FIG. 3, the current collector C of the present invention includes a plastic substrate 6 and two metal layers 7. By using the plastic substrate 6 and the metal layer 7 together, the present invention can have the advantages of light weight of the plastic substrate 6 and good conductive effect of the metal layer 7. In order to allow the electrons on opposite sides of the current collector C to move freely, two metal layers 7 are respectively disposed on two opposite surfaces of the plastic substrate 6, and the two metal layers 7 are electrically connected to each other through a conductive structure.

The material of the plastic substrate 6 can be Polyimide (PI), Polypropylene (PP), Liquid Crystal Polymer (LCP), Polyethylene Terephthalate (PET) , Polystyrene (PS), Polyethylene (PE), Polyvinyl Chloride (PVC), Polycarbonate (PC), Ethylene-vinyl Acetate Copolymer, EVA), Acrylonitrile Butadiene Styrene Copolymer (ABS) or polyurethane (PU), but not limited thereto. In this embodiment, the material of the plastic substrate 6 is preferably polyimide. In addition, the plastic substrate 6 may be a porous plastic substrate, and the material of the plastic substrate 6 may be polystyrene, polyethylene, polyvinyl chloride, polycarbonate, ethylene vinyl acetate copolymer, acrylonitrile butadiene styrene Copolymer or polyurethane.

The plastic substrate 6 has a lower density than metal. Therefore, for the current collector C of the same volume, the current collector C of the present invention includes the plastic substrate 6, so compared to the metal current collector, Has lighter weight and lower manufacturing cost. In this embodiment, the thickness of the plastic substrate 6 is 2 μm to 8 μm, but the invention is not limited to this.

The two metal layers 7 are respectively disposed on an upper surface 601 and a lower surface 602 of the plastic substrate 6 so that the electrons on both sides of the current collector C can move freely. The materials of the two metal layers 7 may be the same or different metals. In a preferred embodiment, the material of the two metal layers 7 is the same metal. When the current collector C is a negative electrode current collector, the material of the two metal layers 7 is copper. When the current collector C is a positive electrode current collector, the material of the two metal layers 7 is aluminum.

In order to electrically connect the two metal layers 7 to each other, the current collector C for a lithium battery of the present invention further includes a conductive structure. The conductive structure may be an outer conductive structure and/or an inner conductive structure. However, the difference in the names of the outer conductive structure and the inner conductive structure is only for convenience of description, and does not impose any substantial limitation on the conductive structure. Hereinafter, the detailed features of the conductive structure will be described in detail with examples.

In FIG. 3, the current collector C of this embodiment further includes an outer conductive structure 8 to provide an electrical conduction path between the two metal layers 7. Furthermore, the plastic substrate 6 has at least one side surface 603 connected between the upper surface 601 and the lower surface 602, and the outer conductive structure 8 is disposed adjacent to the side surface 603 of the plastic substrate 6. In one of the embodiments, the outer conductive structure 8 is disposed on the side surface 603 of the plastic substrate 6 and is in contact with the plastic substrate 6.

In another embodiment, the outer conductive structure 8 is adjacent to the side surface 603 of the plastic substrate 6 but not in contact with the plastic substrate 6. Regardless of whether the outer conductive structure 8 is in contact with the plastic substrate 6 or not, the outer conductive structure 8 is connected between the two metal layers 7 so that the two metal layers 7 separately provided are electrically connected. The outer conductive structure 8 may exist in the form of a sheet, a strip or a tape. As long as the two metal layers 7 can be electrically connected, the shape and structure of the outer conductive structure 8 are not limited.

Specifically, the outer conductive structure 8 has a first end, a second end, and a main body connected between the first end and the second end. The outer conductive structure 8 is connected to the two metal layers 7 through the first end portion and the second end portion respectively, and the main body portion is disposed adjacent to the side surface 603 of the plastic substrate 6 and can be bent and extended along the side surface 603 of the plastic substrate 6. In this way, the two separate metal layers 7 can be electrically connected and electrically connected to each other through the arrangement of the outer conductive structure 8, so as to achieve the effect of maintaining the same potential on both sides of the current collector C.

The materials of the outer conductive structure 8 and the two metal layers 7 of the present invention may be the same or different metals. In this embodiment, the materials of the outer conductive structure 8 and the two metal layers 7 are the same metal. In other words, when the current collector C is a negative electrode current collector, the material of the outer conductive structure 8 is copper. When the current collector C is a positive electrode current collector, the material of the outer conductive structure 8 is aluminum. In this embodiment, the two metal layers 7 and the outer conductive structure 8 can be formed in the same process step to reduce the number of process steps.

The metal layer 7 of the present invention is formed on the plastic substrate 6 by means of chemical plating, sputtering or evaporation, so the thickness of the metal layer 7 can be easily adjusted, but it is not limited thereto. Regarding the above-mentioned formation methods of electroless plating, sputtering or vapor deposition, the thinner the thickness of the metal layer 7 is, the lower the manufacturing cost of the current collector C and the shorter the production time. Moreover, since the density of plastic is lower than that of metal, for the current collector C of the same volume, when the thickness of the metal layer 7 is thinner, the current collector C can have a lighter weight.

As mentioned above, the two metal layers 7 and the outer conductive structure 8 can be formed in the same process step. In this way, the two metal layers 7 and the outer conductive structure 8 can be integrally formed, as shown in FIG. 3. In FIG. 3, the two metal layers 7 and the outer conductive structure 8 are integrally formed to completely cover the plastic substrate 6, but the present invention is not limited to this.

The outer conductive structure 8 in FIG. 3 is disposed on the entire side 603 of the plastic substrate 6, but the present invention is not limited to this. As long as the two metal layers 7 that are not originally connected can be electrically connected to each other, the outer conductive structure 8 can also only partially cover the side surface 603 of the plastic substrate 6, as shown in FIG. 4.

In FIG. 4, the outer conductive structure 8 is only adjacent to a part of the side surface 603 of the plastic substrate 6. The outer conductive structure 8 is also connected to the two metal layers 7 through the first end and the second end, respectively. The main body is bent and extends along the side 603 of the plastic substrate 6.

In addition, referring to FIG. 5, in another embodiment, the plastic substrate 6 of the present invention may be formed with a plurality of through holes 60, and the plurality of through holes 60 communicate with the upper surface 601 and the lower surface 602 of the plastic substrate 6. The via 60 on the plastic substrate 6 can be formed by laser processing, but it is not limited to this. It is worth noting that after the through holes 60 are formed on the plastic substrate 6, the weight of the current collector C can be reduced, the adhesion between the current collector C and the electrode material 5 can be improved, and the electrode material 5 that can be filled is increased. , And can achieve the effect of increasing the capacity of the lithium battery.

The current collector C in another embodiment of the present invention uses a plastic substrate 6 as shown in FIG. 5, and two metal layers 7 are also provided on the upper surface 601 and the lower surface 602 of the plastic substrate 6. Please refer to FIGS. 6 and 7 together. After a plurality of via holes 60 are formed, the current collector C of the present invention may further include an inner conductive structure 9 to provide electrical conduction between the two metal layers 7 path. The inner conductive structure 9 is disposed in the plurality of via holes 60 and is electrically connected to the two metal layers 7.

Specifically, the inner conductive structure 9 has a first end, a second end, and a main body connected between the first end and the second end. The inner conductive structure 9 is electrically connected to the two metal layers 7 through the first end portion and the second end portion, respectively, and the main body portion is disposed in the via hole 60 and can be bent and extended along the inner wall surface of the via hole 60. The main body of the inner conductive structure 9 can be completely or partially filled in the via hole 60, or it can be attached to the wall of the via hole 60 in a ring shape. In this way, the two metal layers 7 that are not originally connected can be mutually conductive and electrically connected through the arrangement of the inner conductive structure 9 so as to achieve the effect of maintaining the same potential on both sides of the current collector C.

The materials of the inner conductive structure 9 and the two metal layers 7 of the present invention may be the same or different metals. In this embodiment, the materials of the inner conductive structure 9 and the two metal layers 7 are the same metal. In this embodiment, when the current collector C is a negative electrode current collector, the material of the inner conductive structure 9 is copper. When the current collector C is a positive electrode current collector, the material of the inner conductive structure 9 is aluminum. Moreover, the two metal layers 7 and the inner conductive structure 9 can be formed in the same process step to reduce the number of process steps.

As mentioned above, the two metal layers 7 can be formed on the plastic substrate 6 by chemical plating, sputtering or evaporation. Therefore, the two metal layers 7 and the inner conductive structure 9 can be formed in the same process step to achieve the effect of simplifying the process steps. In this way, the two metal layers 7 and the inner conductive structure 9 can be integrally formed, that is, as shown in the structures of FIGS. 6 and 7.

In the embodiment of FIGS. 6 and 7, the current collector C also has an outer conductive structure 8 similar to the foregoing, and the two metal layers 7, the outer conductive structure 8 and the inner conductive structure 9 are formed in the same process step. In addition, the two metal layers 7, the outer conductive structure 8 and the inner conductive structure 9 are integrally formed to completely cover the plastic substrate 6, but the present invention is not limited to this. It is worth noting that the outer conductive structure 8 and the inner conductive structure 9 of the present invention do not need to exist at the same time, that is, the two metal layers 7 can be electrically connected to each other only through the outer conductive structure 8 or the inner conductive structure 9.

[Resistance test]

In order to compare the difference between the current collector C of the present invention and the commercially available copper foil, the present invention first prepared the current collector C as shown in FIG. 3 (there is no via 60 on the plastic substrate 6, the metal layer 7 and the outer conductive structure 8 The current collector C) completely covering the plastic substrate 6, forming a metal layer 7 of different thicknesses on the same plastic substrate 6. The detailed thickness of the metal layer 7 and the resistance result of the current collector C are shown in Table 1 below. For comparison with commercially available copper foil, the metal layer 7 in this test example is copper. In addition, the resistance measurement results of commercially available copper foils of different thicknesses are also listed in Table 1 below.

Table 1: Comparison of the resistance value of the current collector of the present invention and the commercially available copper foil. The current collector of the present invention Commercial copper foil Metal layer thickness (μm) Resistance value (Ohm/sq.) Copper foil thickness (μm) Resistance value (Ohm/sq.) 0.25 0.1450 - - 0.5 0.0201 - - 1 0.0146 - - 2 0.0088 2 0.0092 3 0.0059 - - 6 0.0031 6 0.0030 8 0.0023 - - 10 0.0018 10 0.0018 12 0.0015 12 0.0016

It can be seen from the content of Table 1 that the current collector C with the metal layer 7 formed on the plastic substrate 6 of the present invention has a resistance value similar to that of commercially available copper foil. That is, the current collector C of the present invention can directly replace the commercially available copper foil. Moreover, compared with the commercially available copper foil, the current collector C of the present invention has a lighter weight, which can effectively reduce the weight of the lithium battery, so as to achieve the effect of lightening and thinning of electronic products.

In this embodiment, the thickness of the metal layer 7 is preferably 0.2 μm to 3 μm, but it can be adjusted according to requirements in actual use, and is not limited to this. When the thickness of the regulating metal layer 7 is between 0.2 μm and 3 μm, the current collector C can have the characteristics of light weight and have a certain structural strength. It can avoid breaking or stretching deformation due to force when coating and rolling electrode material. According to the results in Table 1, when the thickness of the regulating metal layer 7 is between 0.2 μm and 3 μm, the resistance value of the current collector C is 0.15 Ohm/sq. or less than 0.15 Ohm/sq. To achieve the effect of collecting charges.

In addition, in terms of the manufacturing method, the present invention is to provide a metal layer 7 on the plastic substrate 6, which is more suitable for manufacturing a thinner metal layer 7 than the conventional method of providing the metal layer 7 by rolling. In detail, according to the content of the present invention, if the metal layer 7 with a thinner thickness is formed on the plastic substrate 6 by means of chemical plating, sputtering or evaporation, the manufacturing cost, the manufacturing time and the weight can be reduced. Moreover, since the metal layer 7 is disposed on the plastic substrate 6, the plastic substrate 6 can be used as a base material for forming the metal layer 7 to provide the metal layer 7 with a certain degree of tear strength. In this way, the metal layer 7 will not be damaged or broken due to force during subsequent manufacturing or processing due to its thin thickness. However, compared to the general method of using rolled copper foil or ultra-thin copper foil carried by a carrier to form a thinner metal layer 7, when the electrode material is continuously coated and arranged on a roll-to-roll basis, the thickness can only be extremely thin. The metal layer (approximately 5 microns to 6 microns) is used as a support, so the metal layer is prone to tearing, notch or extension deformation due to process tension, which leads to problems such as low yield, high manufacturing cost, and reduced battery performance.

[Beneficial effects of the embodiment]

One of the beneficial effects of the present invention is that the current collector C and electrode structure for lithium batteries provided by the present invention can be electrically connected to each other through the "plastic substrate 6" and the "two metal layers 7". The technical features are such that the current collector C of the present invention can replace the existing current collector, and has a lighter weight and a smaller volume to meet the trend of thinner and lighter electronic products.

Furthermore, the current collector C and electrode structure for lithium batteries provided by the present invention can reduce the damage of the current collector C through the technical feature of "the plastic substrate 6 is formed with multiple through holes 60" The weight, the adhesion between the current collector C and the electrode material 5 can be improved, and the electrode material 5 that can be filled can be increased to indirectly increase the electric capacity of the lithium battery.

Furthermore, the current collector C and electrode structure for lithium batteries provided by the present invention can be formed on the two metal layers 7 by means of chemical plating, sputtering or evaporation. The technical feature of "on the plastic substrate 6" forms a thinner metal layer 7 with a lower cost and shorter manufacturing time, which can reduce the weight and volume of the current collector C, and is compared with the use of rolled copper foil or carrier As far as the ultra-thin copper foil is used, it is more conducive to improving the manufacturing yield.

More specifically, the current collector C and electrode structure for lithium batteries provided by the present invention can pass through "the side surface 602 is provided with an outer conductive structure 8" or "the through hole 60 is provided with an inner The technical feature of the conductive structure 9" allows the two metal layers 7 to be electrically connected to each other to maintain the same potential on both sides of the current collector C.

The content disclosed above is only a preferred and feasible embodiment of the present invention, and does not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the description and schematic content of the present invention are included in the application of the present invention. Within the scope of the patent.

1: positive 2: Isolation film 3: negative electrode 4: Insulator 5: Electrode material 601: upper surface 602: lower surface 603: side 60: Via 7: Metal layer 8: External conductive structure 9: Internal conductive structure C: collector

FIG. 1 is a schematic diagram of the three-dimensional structure of the lithium battery of the present invention.

Fig. 2 is a schematic side sectional view of part of the lithium battery of the present invention.

Fig. 3 is a schematic side sectional view of the current collector of the present invention.

FIG. 4 is a schematic side sectional view of a current collector according to another embodiment of the invention.

FIG. 5 is a three-dimensional schematic diagram of the plastic substrate of the present invention.

FIG. 6 is a three-dimensional schematic diagram of a current collector according to another embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view of the VII-VII section of Fig. 6.

6: Plastic substrate

601: upper surface

602: lower surface

603: side

7: Metal layer

8: conductive structure

C: collector

Claims (12)

A current collector for a lithium battery, comprising: a plastic substrate with two opposite surfaces; and two metal layers, the two metal layers are respectively provided on two sides of the plastic substrate Are electrically connected to each other through a conductive structure. The current collector for lithium batteries as described in item 1 of the scope of patent application, wherein the material of the plastic substrate is polyimide, polypropylene, liquid crystal polymer, polyethylene terephthalate, poly Styrene, polyethylene, polyvinyl chloride, polycarbonate, ethylene vinyl acetate copolymer, acrylonitrile butadiene styrene copolymer or polyurethane. The current collector for a lithium battery according to the first item of the scope of patent application, wherein, when the material of the two metal layers is copper, the current collector for the lithium battery is a negative electrode current collector. The current collector for a lithium battery according to the first item of the scope of patent application, wherein, when the material of the two metal layers is aluminum, the current collector for the lithium battery is a positive electrode current collector. The current collector for a lithium battery according to the first item of the scope of patent application, wherein the plastic substrate has a side surface connecting two surfaces, the conductive structure is an outer conductive structure, and the outer conductive structure The structure is arranged adjacent to the side surface, and the outer conductive structure is electrically connected to the two metal layers. The current collector for a lithium battery according to item 5 of the scope of patent application, wherein the material of the outer conductive structure is the same as the material of the two metal layers. The current collector for a lithium battery as described in item 6 of the scope of patent application, wherein the outer conductive structure and the two metal layers are integrally formed. The current collector for a lithium battery according to claim 1, wherein the plastic substrate is formed with a plurality of through holes, and the plurality of through holes communicate with the two surfaces of the plastic substrate . The current collector for a lithium battery according to item 8 of the scope of patent application, wherein the conductive structure is an inner conductive structure, and each via hole is provided with an inner conductive structure, and the inner conductive structure is The two metal layers are electrically connected. The current collector for a lithium battery according to the first item of the scope of patent application, wherein the two metal layers are formed on the two plastic substrates by chemical plating, sputtering or evaporation. On the surface. The current collector for a lithium battery according to the first item of the scope of patent application, wherein the thickness of the metal layer is 0.2 to 3 microns, and the resistance value of the current collector is less than or equal to 0.15 Ohm/square . An electrode structure for a lithium battery, comprising: a current collector, which is the current collector for a lithium battery as described in any one of the first to 11 of the scope of patent application; and two electrode materials, two The two electrode materials are respectively formed on the two metal layers of the current collector.

Images