[0026]Reference nowFigure 1A Some aspects of the disclosed subject matter include an energy storage device 100 having an axial structure 102. In some embodiments, the energy storage device 100 includes two or more rigid energy storage units 104 arranged along the axial structure 102. In some embodiments, the energy storage device 100 includes a plurality of energy storage units 104. In some embodiments, the conductive flexible member 106 separates adjacent rigid energy storage cells 104. Reference nowFigure 1B In some embodiments, the energy storage device 100 is configured such that L/a is between 0.30 and 1.0, where L is the length of the conductive flexible member 106, and a is the rigid energy storage unit 104 adjacent to the conductive flexible member. The length of energy storage.
[0027]Reference nowFigure 1C In some embodiments, the axial structure 102 includes multiple layers 108. In some embodiments, the plurality of layers includes an anode layer 110, a cathode layer 112, a first current collector layer 114, a second current collector layer 116, one or more separator layers 118, and one or more tape layers 120 Or a combination. In some embodiments, the anode layer 110 includes graphite. In some embodiments, the first current collector layer 114 is disposed above the anode layer 110. In some embodiments, the first collector layer 114 includes copper. In some embodiments, the first separator layer 118A is disposed between the anode layer 110 and the cathode layer 112. In some embodiments, the cathode layer 112 includes lithium. In some embodiments, the cathode layer 112 is composed of lithium metal, a lithium compound, or a chemically similar material or a combination thereof. In some embodiments, the cathode layer 112 is made of LiCoO2, Li(NixCoyMnz)O2, LiFePO4, Li4Ti5O12Or a combination thereof. In some embodiments, one or more separator layers 118 include polyethylene, polypropylene, or a combination thereof. In some embodiments, the second current collector layer 116 is disposed on the cathode layer 112. In some embodiments, the second current collector layer 116 is disposed between the cathode layer 112 and the second separator layer 118B. In some embodiments, the second current collector layer 116 includes aluminum. In some embodiments, the conductive flexible component 106 includes a metal layer disposed between the plurality of tape layers 120. In some embodiments, the conductive flexible component 106 includes a metal layer disposed between two tape layers 120.
[0028]Reference nowFigure 2A-Figure 2D In some embodiments, at least some of the layers 108 are folded into a stack to define a rigid energy storage unit 104. In these embodiments, the rigid energy storage unit 104 includes multiple folded layers 108'. In some embodiments, multiple folded layers 108' are folded versions of layer 108. In some embodiments, the plurality of folded layers 108' is a layer 108 that is folded onto itself. In some embodiments, the energy storage device 100 includes an axial backbone 122. In some embodiments, the axial backbone 122 includes a layer 108, a layer 108', or a combination thereof. In some embodiments, multiple folded layers 108' wrap around the axial backbone 122, which will be discussed in more detail below.
[0029]Now for specific referenceFigure 2B In some embodiments, the energy storage device 200B includes an axial structure 202B. The energy storage device 200B includes a plurality of rigid energy storage units 204B. The rigid energy storage unit 204B is composed of a plurality of folded layers 208B', which are folded, for example, by winding the layer 208B at least once around the axial backbone 222B. The rigid energy storage unit 204B may have any suitable shape, such as oval, circular, polyhedron, zigzag, etc. or a combination thereof. In some embodiments, multiple layers 208B are provided in a comb structure having one or more tooth portions 224B extending from the axial backbone 222B. In some embodiments, multiple layers 208B are first stacked to align the axial backbone 222B of adjacent layers. The tooth portion 224B is then wrapped around the axial backbone 222B to define the rigid energy storage unit 204B. In some embodiments, the conductive flexible member 206B is disposed between adjacent rigid energy storage units 204B. In some embodiments, the conductive flexible member 206B includes a metal layer disposed between multiple tape layers.
[0030]Now for specific referenceFigure 2C In some embodiments, the energy storage device 200C includes an axial structure 202C. The energy storage device 200C includes a plurality of rigid energy storage units 204C. The rigid energy storage unit 204C is composed of a plurality of folded layers 208C' folded onto each other. In some embodiments, multiple layers 208C are folded onto each other such that the energy storage device 200C adopts a generally zigzag configuration. In some embodiments, the conductive flexible member 206C is disposed between adjacent rigid energy storage units 204C. In some embodiments, the conductive flexible member 206C includes a metal layer disposed between one or more tape layers 220C.
[0031]Reference nowFigure 2D In some embodiments, the energy storage device 200D includes an axial structure 202D. The energy storage device 200D includes at least two rigid energy storage units 204D. As discussed above, the rigid energy storage unit 202D is composed of, for example, multiple folded layers 208D' assembled according to various embodiments discussed elsewhere in this disclosure. The rigid energy storage unit 204D may have any suitable shape, such as oval, circular, polyhedron, zigzag, etc. or a combination thereof. In some embodiments, the conductive flexible member 206D is disposed between adjacent rigid energy storage units 204D. In some embodiments, the conductive flexible member 206D includes a metal layer disposed between the plurality of tape layers 220D. In some embodiments, the conductive flexible member 206D includes one or more folds 226D, thereby enabling the conductive flexible member to be stretched from a first length to a second length.
[0032]Without wishing to be bound by theory, the stretchability of the energy storage device 100 depends on the relative size of the conductive flexible member 106 (stretched length, L) and the energy storage unit 104 (energy storage length, a). In the compressed state:
[0033]L=2Nr+2r
[0034]Where N is the number of cycles and r is the bending radius. The minimum value of N is 1.
[0035]In the stretched state, the length L of the conductive flexible member 206D is replaced by l.
[0036]l=πr(N+1)+N(h-4r)+2r(N-1)
[0037]Stretchability can be defined as:
[0038]
[0039]The relative energy density can be defined as:
[0040]
[0041]Maximum strain:
[0042]
[0043]Where t is the thickness of the conductive flexible member 106 having the tape layer 120. In some exemplary embodiments, t=0.270mm. When r is equal to 0.75 mm, ε = 18.0%, and when r is equal to 1 mm, ε = 13.5%.
[0044]By way of example, suppose that r can be 0.75 mm or 1 mm, a is 10 mm, and h is 5 mm. Then, N as an integer changes. useFigure 2D In the design shown in, the given bending radius r is equal to 0.75mm, and when the ratio of L/a is 0.30, the stretchability can reach about 29%, and the corresponding energy density is about 77% of that of a conventional packaged battery %.
[0045]Reference nowimage 3 The energy storage device 100 includes a housing 128 that surrounds two or more rigid energy storage units 104. In some embodiments, the housing 124 includes an electrolyte material, such as LiPF in ethylene carbonate/diethyl carbonate (1:1 volume/volume)6. In some embodiments, the housing 124 includes a bag. In some embodiments, the bag includes an aluminum layer.
[0046]Reference nowFigure 4 Some aspects of the present disclosure include a method 400 of manufacturing an energy storage device. At 402, an axial structure including multiple layers is formed. At 404, the multiple layers are folded onto themselves at the first position one or more times, thereby creating a rigid energy storage unit at the first position. At 406, multiple layers are folded one or more times onto themselves at additional locations to create additional rigid energy storage units at additional locations. In some embodiments, folding the layer one or more times onto itself at additional locations produces additional rigid energy storage units with adjacent flexible components in a zigzag configuration. As discussed above, in some embodiments, the conductive flexible member is adjacent to the rigid energy storage unit and connects the adjacent rigid energy storage unit. In some embodiments, at 408, adjacent flexible components are laminated with a tape layer. In some embodiments, the conductive flexible member includes a metal layer disposed between multiple (eg, at least two) tape layers. At 410, the axial structure is sealed in a housing (e.g., aluminized bag).
[0047]Reference nowFigure 5 In some embodiments, the method 500 includes providing at 502 an axial structure including a first electrode layer and a second electrode layer. As discussed above, in some embodiments, the first electrode layer is an anode layer including graphite, and the second electrode layer is a cathode layer including lithium. At 504, the axial structure is cut to create multiple branches extending from the axial backbone. At 506, the plurality of branches are wound around the axial backbone to provide two or more rigid energy storage units and a conductive flexible member that separates adjacent rigid energy storage units. At 508, the axial backbone is laminated at the conductive stretchable member with a tape layer. At 510, the axial structure is sealed in an aluminum-plated housing that includes an electrolyte material.
[0048]The advantages of the method and system of the present disclosure are that they exhibit high energy density (275Wh/L, which is 96.4% of their conventional counterparts) and high foldability by virtue of the folded rigid energy storage segments connected by conductive flexible parts. And excellent electrochemical performance. The conductive flexible component functions in a similar way to the soft marrow between the vertebrae in the spine, thereby providing excellent flexibility for the entire device. Even when various mechanical deformations are applied, stable cycles over multiple cycles can be achieved, and the initial discharge capacity is 151mAhg-1And the retention (retention) is 94.3%.
[0049]Foldable batteries with controllable geometry are easy to manufacture to be compatible with different devices. In addition, all the materials used in the manufacture of these batteries have proven to be inexpensive. In the end, the device has also withstood the test of continuous dynamic mechanical load testing, and therefore proved to be much more mechanically robust than conventional battery designs. Reference nowFigure 6The foldable battery according to some embodiments of the present disclosure has been shown to be powered by 17 LEDs, and even with continuous mechanical deformation during lighting, the brightness of the LED remains stable. Even with high current density (range 0.5C to 3C), the performance of the battery is very good.
[0050]The advantages of the systems of the present disclosure are also that they decouple the stretchable component from the energy storage component. Therefore, high energy density and high stretchability can be achieved at the same time. In some embodiments, the tape is only applied to the conductive flexible member, so it does not cause redundant volume in the energy storage unit, and has little effect on the volumetric energy density.
[0051]Although the disclosed subject matter has been described and illustrated with respect to the embodiments of the disclosed subject matter, those skilled in the art should understand that the features of the disclosed embodiments may be combined, rearranged, etc., to be within the scope of the present invention Additional embodiments are produced therein, and various other changes, omissions, and additions can be made therein and without departing from the spirit and scope of the present invention.
