阅读说明：本技术 柔性电池及其折叠电芯和制作方法 (Flexible battery, folding battery core and manufacturing method thereof ) 是由 支春义 赵伟 唐子杰 李洪飞 朱加雄 于 2020-05-27 设计创作，主要内容包括：本发明公开了一种柔性电池及其折叠电芯和制作方法,通过间歇式或横/竖条纹挤压涂布方式在正、负极箔材上涂布电极材料,其中涂布有电极材料的位置形成单元区域,而空白位置形成间歇区域,然后对单元区域进行折叠或卷绕制成折叠电芯,制作方便,节省去传统模切工序,一体性好,封装方便；将折叠电芯封装成柔性电池,柔性电池中折叠或卷绕部分形成厚度较厚的储能单元作为能量储存点,保证电池能量密度,而柔性电池中厚度较薄的柔性单元作为电池弯曲点来提供电池柔性,确保柔性电池同时具有较好的柔性和能量密度。另外柔性电池还加设有缓冲结构,可以固定单元、减小间歇单元交界处应力,利于包膜整形封装,确保产品质量。(The invention discloses a flexible battery, a folding battery cell and a manufacturing method thereof.A positive foil and a negative foil are coated with electrode materials in an intermittent or horizontal/vertical stripe extrusion coating mode, wherein the position coated with the electrode materials forms a unit area, and a blank position forms an intermittent area; the folding battery core is packaged into a flexible battery, the folding or winding part of the flexible battery forms an energy storage unit with thicker thickness as an energy storage point, the energy density of the battery is ensured, the flexible unit with thinner thickness in the flexible battery serves as a battery bending point to provide the flexibility of the battery, and the flexible battery is ensured to have better flexibility and energy density at the same time. In addition, the flexible battery is additionally provided with a buffer structure, so that the unit can be fixed, the stress at the junction of the intermittent units can be reduced, the shaping and packaging of the coating can be facilitated, and the product quality can be ensured.)

1. A folding electric core comprises a positive plate, a diaphragm and a negative plate which are sequentially superposed, and is characterized in that the positive plate comprises a positive foil and an electrode material intermittently coated on the positive foil; the negative plate comprises a negative foil and an electrode material intermittently coated on the negative foil; the energy storage device comprises a positive electrode foil, a negative electrode foil, an energy storage unit and a flexible unit, wherein the positive electrode foil and the negative electrode foil are coated with electrode materials, part of the positive electrode foil and part of the negative electrode foil which are not coated with blank form a unit area, the unit area is folded or wound to form the energy storage unit, the flexible unit is formed in the intermittent area between every two adjacent energy storage units, and the flexible unit and the energy storage unit are of an integrated connection structure.

2. The folded battery cell of claim 1, wherein an inner buffer layer is formed at a connection transition of the flexible unit and the energy storage unit by an inner buffer material.

3. The folded battery cell of claim 1, wherein a surface of the positive foil is coated with an adhesion-promoting coating layer having a thickness of 1-5 μm.

4. The folded battery cell of claim 1, wherein a tackifying coating with a thickness of 1-5 μm is coated on the surface of the negative foil.

5. The folding battery cell of claim 1, wherein the number of the positive electrode sheets is one, the number of the negative electrode sheets is two, the number of the separators is two, and the negative electrode sheets, the separators, the positive electrode sheets, the separators and the negative electrode sheets are sequentially stacked.

6. The folded cell of claim 1, wherein the electrode material on the positive foil is aligned with the electrode material on the negative foil.

7. The folded battery cell of any of claims 1-6, wherein the energy storage unit has a cross-sectional profile that is one of circular, triangular, square, rectangular, trapezoidal, elliptical, and prismatic.

8. A manufacturing method of a folded battery cell is characterized in that an anode plate and a cathode plate are correspondingly manufactured by coating electrode materials on an anode foil and a cathode foil in an intermittent transfer coating or horizontal/vertical stripe extrusion coating mode, wherein the positions of the anode foil and the cathode foil coated with the electrode materials form unit areas, blank positions form intermittent areas, the anode plate, a diaphragm and the cathode plate are sequentially overlapped to form an anode plate group and a cathode plate group, the anode plate group and the cathode plate group are respectively folded or wound corresponding to the positions of the unit areas to form a plurality of energy storage units, and the intermittent areas between every two adjacent energy storage units form flexible units for bending.

9. A flexible battery, characterized in that it comprises a folded cell according to any of claims 1 to 7 and an envelope enclosing the folded cell.

10. The flexible battery according to claim 9, wherein the capsule forms a convex portion and a concave portion corresponding to the energy storage unit and the flexible unit, and an outer buffer material is arranged at a connecting transition between the outer concave portion and the outer convex portion to form an outer buffer layer.

Technical Field

The invention belongs to the technical field of flexible batteries, and particularly relates to a flexible battery, a folding battery cell and a manufacturing method thereof.

Background

In recent years, flexible electronic technology has attracted wide attention worldwide as an emerging technology, and more flexible electronic devices, such as flexible electronic displays, Organic Light Emitting Diodes (OLEDs), printed RFIDs, flexible health medical products, and the like, are emerging. This provides a wide development space for their energy supply devices.

The flexible battery can be repeatedly bent within a certain bending radius range without failure in the use process, and the industry people explore a lot in the aspects of electrode materials of the flexible battery, battery structures, battery thinning and the like, and some battery materials can reduce the problem of material falling at the bent part to a certain extent, but can not solve the problem fundamentally; the battery is thinned, so that the capacity of the battery is greatly limited; the improvement of the structure reduces the energy density of the battery and also affects the flexibility of the battery to some extent.

For example, publication No. CN106207195B entitled "a laminated flexible battery and a method for manufacturing the same" discloses a laminated flexible battery and a method for manufacturing the same, (1) punching a positive electrode current carrier; the anode current-carrying body comprises more than two anode current-carrying pieces, an anode connecting piece and an anode tab welding piece, and adjacent anode current-carrying pieces are connected in series through the anode connecting piece; (2) punching a negative electrode current carrier; the negative electrode current-carrying fluid comprises more than two negative electrode current-carrying pieces, a negative electrode connecting piece and a negative electrode tab welding piece, and adjacent negative electrode current-carrying pieces are connected in series through the negative electrode connecting piece; (3) coating a positive electrode material on the surface of the positive electrode current-carrying sheet, and coating a negative electrode material on the surface of the negative electrode current-carrying sheet; (4) stacking the positive current-carrying fluid, the negative current-carrying fluid and the diaphragm to form an electric core by using a stacking process, wherein the stacking positions of the positive current-carrying piece and the negative current-carrying piece are superposed, and the mutually overlapped positive current-carrying piece and negative current-carrying piece form an electric core monomer; (5) and (4) placing the battery core into an aluminum plastic film for packaging. According to the method, the pole piece with the required regular or irregular shape is obtained by die cutting and the like, and the poor processing such as burrs and the like are easy to occur in the die cutting process, so that the finished product rate of the battery is influenced finally; and moreover, the risk that the aluminum-plastic film is easy to break due to uneven concave parts is reduced through the corner seal, and the difficulty in manufacturing and packaging the battery cell is increased.

Disclosure of Invention

In view of the above disadvantages, the present invention provides a flexible battery, a folded battery cell thereof, and a manufacturing method thereof.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a folding electric core comprises a positive plate, a diaphragm and a negative plate which are sequentially superposed, wherein the positive plate comprises a positive foil and an electrode material intermittently coated on the positive foil; the negative plate comprises a negative foil and an electrode material intermittently coated on the negative foil; the energy storage device comprises a positive electrode foil, a negative electrode foil, an energy storage unit and a flexible unit, wherein the positive electrode foil and the negative electrode foil are coated with electrode materials, part of the positive electrode foil and part of the negative electrode foil which are not coated with blank form a unit area, the unit area is folded or wound to form the energy storage unit, the flexible unit is formed in the intermittent area between every two adjacent energy storage units, and the flexible unit and the energy storage unit are of an integrated connection structure.

As a preferable scheme of the invention, an inner buffer layer is formed by arranging an inner buffer material at the connecting transition of the flexible unit and the energy storage unit, so that the bending stress concentration is effectively reduced.

In a preferred embodiment of the present invention, a surface of the positive electrode foil is coated with a material capable of enhancing adhesion between the positive electrode material and the positive electrode foil, such as carbon, to form a tie coat layer having a thickness of 1 to 5 μm.

As a preferable scheme of the invention, materials which can enhance the binding property between the negative electrode material and the negative electrode foil, such as carbon, are coated on the inner surface of the negative electrode foil to form a tackifying coating with the thickness of 1-5 mu m; the outer surface of the negative electrode foil is coated with adhesive polymer material, such as PVDF, SBR, etc., with a thickness of 1-5 μm.

As a preferable scheme of the present invention, the number of the positive electrode sheets is one, the number of the negative electrode sheets is two, the number of the separators is two, and the negative electrode sheets, the separators, the positive electrode sheets, the separators and the negative electrode sheets are sequentially stacked to increase the battery capacity.

As a preferable aspect of the present invention, the electrode material on the positive electrode foil is aligned with the electrode material on the negative electrode foil, so that the cell region and the intermittent region can be clearly distinguished.

As a preferable solution of the present invention, the cross-sectional profile of the energy storage unit may be circular, triangular, square, rectangular, trapezoidal, elliptical, prismatic, etc. to meet specific requirements.

A method for manufacturing a folded battery cell comprises the steps of coating electrode materials on positive and negative foils in an intermittent transfer coating or horizontal/vertical stripe extrusion coating mode to obtain a positive plate and a negative plate correspondingly, wherein unit areas are formed at positions where the positive and negative foils are coated with the electrode materials, intermittent areas are formed at blank positions, the positive plate, a diaphragm and the negative plate are sequentially overlapped to form a positive plate group and a negative plate group, the positive plate group and the negative plate group are respectively folded or wound corresponding to the positions of the unit areas to form a plurality of energy storage units, and flexible units are formed in the intermittent areas between every two adjacent energy storage units and are used for bending.

A flexible battery comprises the folding battery core and a coating wrapping the folding battery core. Because the folded battery core is provided with the energy storage unit with thicker thickness and the flexible unit with thinner thickness, the flexible unit with thinner thickness is used as a bending point of the flexible battery. When the coating is wrapped, the coating correspondingly forms a convex part and a concave part corresponding to the energy storage unit and the flexible unit, and an outer buffer layer is formed by an outer buffer material arranged at the connecting transition position between the outer concave part and the outer convex part. The outer buffer material is macromolecule elastic glue with cohesiveness and elasticity after solidification, or finished silica gel, rubber, fiber material or other foaming material.

The invention has the beneficial effects that: coating electrode materials on the positive and negative electrode foils in an intermittent transfer coating or horizontal/vertical stripe extrusion coating mode to correspondingly prepare positive plates and negative plates, wherein the positions coated with the electrode materials form unit areas, and the blank positions form intermittent areas; the folding or winding part forms an energy storage unit with thicker thickness as an energy storage point to ensure the energy density of the battery, the other blank electrode-free material parts form flexible units with thinner thickness as a bending point of the battery to bear the stress generated by the deformation of the battery and provide the flexibility of the battery, the manufactured folding battery core has good integrity, the traditional die cutting process is saved, the process is simple, the bad process phenomena such as burrs and the like are reduced, an inner buffer layer is arranged at the connection transition part of the flexible units and the energy storage unit to play the roles of fixing the units, reducing the stress at the junction of each unit and being beneficial to shaping and packaging of a coating, and the phenomena of damage and leakage of the coating caused by the bending of the battery can be reduced; the folding battery cell is packaged into a flexible battery, the folding or winding part in the folding battery cell is used as an energy storage point to ensure the energy density of the battery, and the intermittent region with the thinner thickness is used as a bending point of the battery to provide the flexibility of the battery, so that the flexible battery is ensured to have better flexibility and energy density at the same time. An outer buffer layer is arranged at the connecting transition position between the outer concave part and the outer convex part of the envelope of the flexible battery, so that the stress concentration of the flexible battery in the bending process is effectively reduced, and the service life is prolonged. In practical application, according to the application scene of the flexible battery, the size of the energy storage unit and the size of the flexible unit are selected to achieve the best flexibility and the best energy density, and therefore the best economic benefit is achieved.

The invention is further illustrated by the following figures and examples.

Drawings

Fig. 1 is a perspective view of a flexible battery in embodiment 1 of the invention.

Fig. 2 is a schematic structural diagram of a folded battery cell in embodiment 1 of the present invention.

Fig. 3 is an enlarged schematic view of the structure of the portion a in fig. 2.

Fig. 4 is a schematic view of a folding structure of a unit region in embodiment 1 of the present invention.

FIG. 5 shows the position and shape of the inner buffer material in example 1 of the present invention.

FIG. 6 shows the position and shape of the outer cushion material in example 1 of the present invention.

Fig. 7 is a schematic view of the winding structure of the unit area in embodiment 2 of the present invention.

Detailed Description

Example 1:

the present embodiment provides a flexible battery 1, which includes a folded battery cell 10, an envelope 20 wrapping the folded battery cell, and an outer buffer layer 310.

The folded battery cell 10 is formed by alternately arranging and integrally connecting a plurality of convex energy storage units 100 and a plurality of concave flexible units 110. Namely, a flexible unit 110 is arranged between two adjacent energy storage units 100, and an energy storage unit 100 is arranged between two adjacent flexible units 110. Specifically, the positive plate and the negative plate are correspondingly prepared by coating electrode materials on the positive foil and the negative foil in an intermittent transfer coating mode, a horizontal stripe extrusion coating mode or a vertical stripe extrusion coating mode. The positions of the positive electrode foil and the negative electrode foil coated with the electrode materials form unit areas, the blank uncoated positions form intermittent areas, the positions of the electrode materials on the positive electrode foil are opposite to the positions of the electrode materials on the negative electrode foil, and the unit areas and the intermittent areas can be obviously distinguished. The positive plate, the diaphragm and the negative plate are sequentially overlapped to form a positive plate group and a negative plate group, the positive plate group and the negative plate group are respectively folded or wound corresponding to the position of each unit area to form a plurality of energy storage units 100, and the flexible unit 110 is formed in the intermittent area between every two adjacent energy storage units 100. In this embodiment, the folded battery cell 10 includes a positive plate, two negative plates, and two diaphragms 103, where the negative plate, the diaphragms 103, the positive plate, the diaphragms 103, and the negative plates are stacked in sequence. The energy storage unit 100 and the flexible unit 110 are all composed of the same layers of positive foil 105, negative foil 101 and diaphragm 103, and are of an integrally connected integral structure, and the difference is whether to coat electrode materials on the positive foil 101 and the negative foil 101. The electrode materials include a positive electrode material 104 and a negative electrode material 102, and the negative electrode material 102 is coated on the negative electrode foil 101, and the positive electrode material 104 is coated on the positive electrode foil 105. Specifically, carbon and other materials capable of enhancing the adhesion between the positive electrode material and the positive electrode foil are coated on the surface of the positive electrode foil 105, so that a first tackifying coating with the thickness of 1-5 μm is formed. Coating materials such as carbon and the like capable of enhancing the binding property between the negative electrode material and the negative electrode foil material on the inner surface of the negative electrode foil material 101 to form a second tackifying coating with the thickness of 1-5 mu m; and coating a high polymer material with adhesive property on the outer surface of the negative electrode foil to form a third tackifying coating, wherein the thickness of the third tackifying coating is 1-5 mu m, and the like, such as high polymer materials like PVDF (polyvinylidene fluoride) and PVA (polyvinyl acetate).

The energy storage unit 100 is obtained by folding the cell region, and fig. 4 i-iii illustrate three folding modes of the cell region, and it should be noted that the embodiment of the present invention is not limited to these illustrated folding modes, and any other suitable folding mode for the pole piece can be taken as a reasonable extension of the present invention. In the design process of the battery, the folding times can be selected according to the capacity and the application of the battery so as to meet the specific use requirement.

The flexible unit 110 includes blank positive and negative electrode sheets and separators, i.e., corresponding to positive and negative foils and separators, which are not coated with electrode materials, and the width dimensions of the flexible unit 110 and the energy storage unit 100 may be designed according to the battery capacity and the application.

Preferably, a buffer structure is additionally arranged. The buffer structure includes an inner buffer layer 300 and an outer buffer layer 310. An inner buffer material is arranged at the connecting transition of the flexible unit 110 and the energy storage unit 100 to form an inner buffer layer 300. Referring to fig. 5, the four schemes i to iv in fig. 5 are shown as the positions and the shapes of the inner buffer layer 300, but are not limited to these four schemes, and the bending stress concentration can be effectively reduced after the inner buffer layer 300 is coated or adhered.

And the outer buffer layer 310 is coated or adhered on the envelope 20. Specifically, after the envelope 20 wraps the folded battery cell 10, because the folded battery cell 10 has the energy storage unit 100 with a relatively thick thickness and the flexible unit 110 with a relatively thin thickness, the envelope 20 correspondingly forms a convex portion and a concave portion corresponding to the energy storage unit 100 and the flexible unit 110, and an outer buffer layer 310 is formed at a connection transition position between the outer concave portion and the outer convex portion by an outer buffer material. Referring to fig. 6, the six schemes i-vi in fig. 6 are shown in the position and shape of the outer buffer layer 310, but are not limited to these six schemes. The outer buffer material is a high-molecular elastic rubber with cohesiveness and elasticity after being cured, or a finished product of silica gel, rubber, fiber material or other foaming materials, and can effectively reduce the concentration of bending stress and prolong the bending life of the flexible battery after the outer buffer layer 310 is coated or adhered.

Example 2:

this embodiment 2 provides a flexible battery, which is different from embodiment 1 in that the energy storage unit 100 in the flexible battery has a different structure. As shown in fig. 7, the energy storage cell 100 is formed by winding a cell region, and the cross-sectional view of the wound shape is a square, triangle, or circle scheme as shown in fig. 7 i-iii, but is not limited thereto. In other embodiments, the cross-sectional profile of the energy storage unit 100 may also be elliptical, prismatic, etc., and it should be understood that embodiments of the present invention are not limited to these illustrated shapes, and any other shape suitable for the cross-section of the energy storage unit may be used as a reasonable extension of the present invention. In addition, the middle part of the winding can be empty, and a winding rod with the same shape can be reserved as a support body, and the like, and the invention is within the protection scope.

The flexible battery can obtain the optimal required battery by adjusting parameters such as the size of the energy storage unit, the number of layers of the positive and negative electrode plate groups in the unit area, the bending radius of the battery in the application process and the like, and meets different individual requirements.

The above example 1-2 is only a preferred embodiment of the present invention, and an intermittent coating process is performed to coat electrode materials on positive and negative foils to obtain positive and negative plates, where the positive and negative plates have unit regions and intermittent regions, the positive and negative plates, the separator, and the negative plate are sequentially stacked to form positive and negative plate groups, and then the positive and negative plate groups are folded or wound corresponding to the positions of the unit regions to form a folded battery cell, so that the manufacturing process is convenient, the conventional die cutting process is omitted, the integrity is good, and the packaging process is convenient; the folding or winding part in the folding battery core is used as an energy storage point to ensure the energy density of the battery, and the intermittent region with the smaller thickness is used as a bending point of the battery to provide the flexibility of the battery, so that the flexible battery is ensured to have better flexibility and energy density at the same time. The present invention is not intended to be limited to the embodiments shown, and all modifications and equivalents thereof can be made without departing from the scope of the present invention.

Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Other batteries, cells and methods of making the same, or similar methods and compositions as described in the above embodiments of the invention are within the scope of the invention.