Flexible batteries, circuit boards and electronic devices

Abstract

A flexible battery, a circuit board and an electronic device, belonging to the field of battery technology. The flexible battery comprises a flexible packaging structure (FES), a plurality of battery cells (100) and a crack detection trace (PCD). The flexible packaging structure (FES) comprises a battery area (AA) and a peripheral area (BB) surrounding the battery area (AA); the battery area (AA) comprises a plurality of rigid areas (A1) and a plurality of bending areas (A2) alternately arranged along a first direction (H1). The plurality of battery cells (100) are arranged in correspondence with the plurality of rigid areas (A1): in the corresponding rigid areas (A1), the battery cells (100) are enclosed in the flexible packaging structure (FES). The crack detection trace (PCD) is located in the peripheral area (BB) and at least partially extends along the first direction (H1); the crack detection trace (PCD) is enclosed in the flexible packaging structure (FES). The flexible battery facilitates the detection of micro cracks at the edge of the flexible battery.

Description

Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to a flexible battery, a circuit board and an electronic device. Background Art

[0002] The edges of flexible batteries are prone to microcracks due to bending, which can lead to failure of flexible battery packaging, leakage, swelling, etc. However, the size of microcracks is very small and cannot be quickly observed by the naked eye.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] The purpose of the present disclosure is to overcome the deficiencies of the above-mentioned prior art and to provide a flexible battery, a circuit board and an electronic device, which are convenient for detecting micro cracks on the edge of the flexible battery.

[0005] According to a first aspect of the present disclosure, there is provided a flexible battery, comprising:

[0006] A flexible packaging structure, comprising a battery area and a peripheral area surrounding the battery area; the battery area comprises a plurality of rigid areas and a plurality of bending areas alternately arranged along a first direction;

[0007] A plurality of battery cells are arranged corresponding to the plurality of rigid regions one by one; in the corresponding rigid regions, the battery cells are enclosed in the flexible packaging structure;

[0008] A crack detection line is located in the peripheral area and at least partially extends along the first direction; wherein the crack detection line is enclosed in the flexible packaging structure.

[0009] According to an embodiment of the present disclosure, the peripheral region includes a first peripheral region and a second peripheral region located on both sides of the battery region; the first peripheral region and the second peripheral region both extend along the first direction;

[0010] The crack detection line includes a first sub-detection line and a second sub-detection line electrically connected to each other; the first sub-detection line runs through the first peripheral area along the first direction, and the second sub-detection line runs through the second peripheral area along the first direction.

[0011] According to an embodiment of the present disclosure, the peripheral area further includes a third peripheral area, and the third peripheral area connects the first peripheral area and the second peripheral area;

[0012] The crack detection line further includes a third sub-detection line that passes through the third peripheral area, and the third sub-detection line connects the first sub-detection line and the second sub-detection line.

[0013] According to an embodiment of the present disclosure, the thickness of the crack detection line is in the range of 0.3 to 1.5 microns.

[0014] According to an embodiment of the present disclosure, the width of the crack detection line is in the range of 0.2 to 1.0 mm.

[0015] According to an embodiment of the present disclosure, the distance between the crack detection trace and the edge of the flexible packaging structure is in the range of 0.5 to 1.5 millimeters.

[0016] According to an embodiment of the present disclosure, the material of the crack detection wiring is a metal material.

[0017] According to an embodiment of the present disclosure, the flexible packaging structure includes a first flexible packaging layer and a second flexible packaging layer stacked in layers; the battery cell is disposed between the first flexible packaging layer and the second flexible packaging layer;

[0018] The crack detection trace is located in the first flexible packaging layer.

[0019] According to an embodiment of the present disclosure, the battery cells are arranged on one side of the first flexible packaging layer and are spaced apart along the first direction;

[0020] The second flexible packaging layer includes a protruding portion covering the battery cells, and includes a recessed portion located between adjacent battery cells.

[0021] According to an embodiment of the present disclosure, the elastic modulus of the first flexible encapsulation layer is greater than the elastic modulus of the second flexible encapsulation layer.

[0022] According to an embodiment of the present disclosure, the first flexible packaging layer is a steel-plastic film.

[0023] According to an embodiment of the present disclosure, the second flexible packaging layer is an aluminum-plastic film.

[0024] According to an embodiment of the present disclosure, along a direction away from the battery core, the first flexible packaging layer includes a first heat sealing layer, a first adhesive layer, a first metal layer, a second adhesive layer and a first protective layer stacked in sequence;

[0025] The crack detection wiring is sandwiched between the second adhesive layer and the first protective layer.

[0026] According to one embodiment of the present disclosure, the flexible battery further includes a flexible conductive layer, which is at least partially encapsulated in the flexible packaging structure and electrically connected to each of the battery cells;

[0027] The flexible conductive layer has a binding area located outside the flexible packaging structure; the binding area has a crack detection pad electrically connected to the crack detection trace.

[0028] According to a second aspect of the present disclosure, there is provided a circuit board, comprising:

[0029] A resistance detection circuit, used to be electrically connected to the crack detection trace of the above-mentioned flexible battery, and configured to be able to detect the resistance of the crack detection trace;

[0030] The bootstrap circuit is used to be electrically connected to the crack detection line, and is configured to receive a first voltage and output a second voltage to the crack detection line; the second voltage is higher than the first voltage.

[0031] According to an embodiment of the present disclosure, the bootstrap circuit includes a voltage boost subcircuit and a logic control subcircuit;

[0032] The boost subcircuit comprises:

[0033] A first capacitor, two ends of which are connected to a first node and a second node respectively;

[0034] A first switch, one end of which is electrically connected to the first node, and the other end of which is used to load a reference voltage;

[0035] a second switch, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the input terminal;

[0036] a third switch, one end of which is electrically connected to the input end, and the other end of which is electrically connected to the first node;

[0037] a fourth switch, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the output end;

[0038] A second capacitor, one end of which is electrically connected to the output end, and the other end of which is used to load the reference voltage;

[0039] The logic control subcircuit is configured to turn on the first switch and the second switch and turn off the third switch and the fourth switch during a charging phase; the logic control subcircuit is also configured to turn off the first switch and the second switch and turn on the third switch and the fourth switch during a discharging phase.

[0040] According to a third aspect of the present disclosure, there is provided an electronic device comprising the above-mentioned flexible battery.

[0041] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0043] Figure 1 The cross-sectional structure diagram of a flexible battery in one embodiment of the present disclosure.

[0044] Figure 2 It is a schematic top view of a flexible packaging structure in one embodiment of the present disclosure.

[0045] Figure 3 It is a schematic top view of each battery cell in one embodiment of the present disclosure.

[0046] Figure 4 It is a schematic diagram of the cross-sectional structure of the first flexible packaging layer in one embodiment of the present disclosure.

[0047] Figure 5 It is a schematic diagram of the cross-sectional structure of the second flexible packaging layer in one embodiment of the present disclosure.

[0048] Figure 6 A schematic diagram of the location of crack detection routing in one embodiment of the present disclosure.

[0049] Figure 7 It is a schematic diagram of the cross-sectional structure of the first flexible packaging layer in one embodiment of the present disclosure.

[0050] Figure 8 FIG. 1 is a schematic diagram of a structure of a circuit board and a crack detection line in cooperation with each other in one embodiment of the present disclosure. Figure 8 The crack detection pin and the crack detection pad are staggered and do not overlap.

[0051] Fig. 9 FIG. 1 is a schematic diagram of an equivalent circuit of a boost subcircuit in one embodiment of the present disclosure.

[0052] Fig.10 1 is a circuit diagram of a boost subcircuit in a charging stage in one embodiment of the present disclosure.

[0053] Fig.11 1 is a circuit diagram of a boost subcircuit in a discharge phase in one embodiment of the present disclosure.

[0054] Description of reference numerals:

[0055] 100, battery cell; 101, battery cell body; 102, positive electrode ear; 103, negative electrode ear; 200, flexible conductive layer; 201, first flexible conductive belt; 202, second flexible conductive belt; FES, flexible packaging structure; F100, first flexible packaging layer; F200, second flexible packaging layer; F301, protruding part; F302, concave part; F101, first heat sealing layer; F102, first adhesive layer; F103, first metal layer; F104, second adhesive layer; F105, first protective layer; F20 1. Second heat-sealing layer; F202. Third adhesive layer; F203. Second metal layer; F204. Fourth adhesive layer; F205. Second protective layer; AA. Battery area; A1. Rigid area; A2. Bending area; BB. Peripheral area; B1. First peripheral area; B2. Second peripheral area; B3. Third peripheral area; B4. Fourth peripheral area; PCD. Crack detection line; PCD1. First sub-detection line; PCD2. Second sub-detection line; PCD3. Third sub-detection line; H1. First direction; H2. Second direction. DETAILED DESCRIPTION

[0056] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0057] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0058] The terms "a", "an", "the" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first" and "second" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0059] The present disclosure provides a flexible battery, see Figure 1 The flexible battery includes a plurality of battery cells 100 arranged at intervals along a first direction H1 and a flexible packaging structure FES covering each of the battery cells 100 .

[0060] See also Figure 1 and Figure 2 , on the flexible packaging structure FES, the area corresponding to the battery cell 100 is the rigid area A1 (that is, the area overlapping with the battery cell 100 is the rigid area A1), and the area between the battery cells 100 is the bending area A2; each bending area A2 and each rigid area A1 constitute a battery area AA where the battery cells 100 are distributed. The flexible packaging structure FES may also include a peripheral area BB surrounding the battery area AA so as to achieve more effective packaging of each battery cell 100. In other words, in the flexible battery disclosed in the present invention, the flexible packaging structure FES has a battery area AA and a peripheral area BB surrounding the battery area AA; the battery area AA includes a plurality of rigid areas A1 and a plurality of bending areas A2 alternately arranged along a first direction H1. Among them, see Figure 2 , both ends of the battery area AA are rigid areas A1. Each battery cell 100 is arranged in a one-to-one correspondence with each rigid area A1; the battery cell 100 is arranged in the corresponding rigid area A1 and is encapsulated in the flexible packaging structure FES. In this way, in the flexible battery disclosed in the present invention, the battery cell 100 is arranged in the rigid area A1 and is encapsulated in the flexible packaging structure FES, and the flexible battery can be bent in the bending area A2. This allows the flexible battery disclosed in the present invention to be bent between adjacent battery cells 100, so that the flexible battery can achieve flexible forms such as bending, folding or twisting.

[0061] Alternatively, see Figure 1, the flexible packaging structure FES includes a first flexible packaging layer F100 and a second flexible packaging layer F200 which are stacked; the battery cell 100 is arranged between the first flexible packaging layer F100 and the second flexible packaging layer F200. In the rigid area A1, the first flexible packaging layer F100 and the second flexible packaging layer F200 are both connected to the battery cell 100 and isolated by the battery cell 100. In the peripheral area BB and the bending area A2, the first flexible packaging layer F100 and the second flexible packaging layer F200 are directly connected to close the rigid area A1. Furthermore, the inner surfaces of the first flexible packaging layer F100 and the second flexible packaging layer F200 are both provided with a heat sealing layer. In this way, in the rigid area A1, the first flexible packaging layer F100 and the second flexible packaging layer F200 are both bonded to the battery cell 100 to fix the battery cell 100. In the peripheral area BB and the bending area A2 , the first flexible packaging layer F100 and the second flexible packaging layer F200 are bonded to each other to achieve packaging of the battery cell 100 .

[0062] In some embodiments, see Figure 1 , the first flexible encapsulation layer F100 can be a flat encapsulation layer; the second flexible encapsulation layer F200 can be a concave-convex encapsulation layer. In this way, the flexible battery has a flat side and a pitted side arranged oppositely; the encapsulation layer of the flexible encapsulation structure FES on the flat side is the first flexible encapsulation layer F100, and the encapsulation layer on the pitted side is the second flexible encapsulation layer F200. When the flexible battery is in a flat state, the first flexible encapsulation layer F100 (flat encapsulation layer) can be laid flat as a plane, and each battery cell 100 is located on one side of the plane. In other words, in the flat state, the first flexible encapsulation layer F100 in the bending area A2 may not be bent into the gap between the battery cells 100. The second flexible encapsulation layer F200 (concave-convex encapsulation layer) may include a protruding portion F301 covering the battery cell 100, and a concave portion F302 located between adjacent battery cells 100. In other words, the morphology of the second flexible encapsulation layer F200 may fluctuate with the battery cell 100. In the rigid area A1, the second flexible packaging layer F200 covers the surface of the battery cell 100 (close to or away from the surface of the first flexible packaging layer F100) and protrudes from the surface of the first flexible packaging layer F100, which is the protruding portion F301 of the second flexible packaging layer F200. In the bending area A2, the second flexible packaging layer F200 is between adjacent battery cells 100 and directly covers the surface of the first flexible packaging layer F100, thus serving as the recessed portion F302 of the second flexible packaging layer F200. For further information, see Figure 1 The protruding portion F301 of the second flexible packaging layer F200 also covers the side surfaces of the battery cells (the surfaces where the battery cells are close to or away from each other). In a further embodiment, the protruding portion F301 of the second flexible packaging layer F200 also covers the end surfaces of the battery cells (the surfaces at both ends of the length direction of the battery cells).

[0063] Of course, in other embodiments of the present disclosure, the first flexible encapsulation layer F100 and the second flexible encapsulation layer F200 may both be concave-convex encapsulation layers.

[0064] Alternatively, see Figure 4 , along the direction away from the battery cell 100, the first flexible packaging layer F100 includes a first heat sealing layer F101, a first metal layer F103 and a first protective layer F105 stacked in sequence. The first heat sealing layer F101 is used to fix the first metal layer F103 and is used for heat sealing packaging. The first metal layer F103 is used to isolate water and oxygen. The first protective layer F105 is used to provide protection for the first flexible packaging layer F100.

[0065] Furthermore, a first adhesive layer F102 is provided between the first heat seal layer F101 and the first metal layer F103; and a second adhesive layer F104 is provided between the first metal layer F103 and the first protective layer F105. In this way, the first heat seal layer F101, the first metal layer F103 and the first protective layer F105 are connected by two adhesive layers. Furthermore, the materials of the first adhesive layer F102 and the second adhesive layer F104 may be different. Of course, in other embodiments of the present disclosure, the materials of the first adhesive layer F102 and the second adhesive layer F104 may also be the same.

[0066] In one embodiment of the present disclosure, the first heat sealing layer F101 may be a polypropylene layer, and in particular, may be a cast polypropylene layer.

[0067] In one embodiment of the present disclosure, the material of the first adhesive layer F102 may be modified polypropylene.

[0068] In one embodiment of the present disclosure, the material of the second adhesive layer F104 may be polyester or polyurethane.

[0069] In one embodiment of the present disclosure, the first protective layer F105 may be a nylon layer.

[0070] Optionally, the thickness of the first flexible encapsulation layer F100 may be in the range of 40 to 150 micrometers, for example, in the range of 80 to 120 micrometers, and for example, in the range of 45 to 55 micrometers.

[0071] Alternatively, see Figure 5 , along the direction away from the battery cell 100, the second flexible packaging layer F200 includes a second heat sealing layer F201, a second metal layer F203 and a second protective layer F205 stacked in sequence. The second heat sealing layer F201 is used to fix the second metal layer F203 and is used for heat sealing packaging. The second metal layer F203 is used to isolate water and oxygen. The second protective layer F205 is used to provide protection for the second flexible packaging layer F200.

[0072] Furthermore, a third adhesive layer F202 is provided between the second heat seal layer F201 and the second metal layer F203; and a fourth adhesive layer F204 is provided between the second metal layer F203 and the second protective layer F205. In this way, the second heat seal layer F201, the second metal layer F203, and the second protective layer F205 are connected by two adhesive layers. Furthermore, the materials of the third adhesive layer F202 and the fourth adhesive layer F204 may be different. Of course, in other embodiments of the present disclosure, the materials of the third adhesive layer F202 and the fourth adhesive layer F204 may also be the same.

[0073] In one embodiment of the present disclosure, the second heat sealing layer F201 may be a polypropylene layer, and in particular, may be a cast polypropylene layer.

[0074] In one embodiment of the present disclosure, the material of the third adhesive layer F202 may be modified polypropylene.

[0075] In one embodiment of the present disclosure, the material of the fourth adhesive layer F204 may be polyester or polyurethane.

[0076] In one embodiment of the present disclosure, the second protective layer F205 may be a nylon layer.

[0077] Optionally, the thickness of the second flexible encapsulation layer F200 may be in the range of 40 to 150 micrometers, for example, in the range of 80 to 120 micrometers, and for example, in the range of 45 to 55 micrometers.

[0078] Alternatively, see Figure 3 The battery cell 100 includes a battery cell body 101 and a positive electrode ear 102 and a negative electrode ear 103 located at both ends of the battery cell body 101. The multiple battery cell bodies 101 are arranged in sequence along the first direction H1, and there is a preset gap between two adjacent battery cells 100.

[0079] Alternatively, see Figure 3 ( Figure 3 The flexible packaging structure is not shown in the figure), the flexible battery may also include a flexible conductive layer 200, and the flexible conductive layer 200 is electrically connected to each battery cell 100. Among them, the portion of the flexible conductive layer 200 electrically connected to each battery cell 100 may be encapsulated in the flexible packaging structure. At least part of the flexible conductive layer 200 may extend out of the flexible packaging structure to be electrically connected to an external circuit (such as a circuit board). The flexible battery is electrically connected to the external circuit through the flexible conductive layer 200 for charging or discharging. In one embodiment of the present disclosure, the flexible conductive layer 200 is at least partially sandwiched between the first flexible packaging layer F100 and the second flexible packaging layer F200.

[0080] Optionally, the portion of the flexible conductive layer 200 extending out of the flexible packaging structure may have an end portion (the end away from the flexible packaging structure) provided with a binding region. In the binding region, the flexible conductive layer 200 may be provided with binding pads, which may include battery pads electrically connected to an external circuit. An external circuit, such as an external flexible circuit board, may be electrically connected to the flexible conductive layer 200 through the battery pads, thereby receiving power provided by the flexible battery or charging the flexible battery.

[0081] In one embodiment of the present disclosure, see Figure 3 The flexible conductive layer 200 includes a first flexible conductive tape 201 and a second flexible conductive tape 202. The first flexible conductive tape 201 is electrically connected to the positive electrode ears 102 of each battery cell 100, so that the positive electrodes of each battery cell 100 are connected in parallel. The second flexible conductive tape 202 is electrically connected to the negative electrode ears 103 of each battery cell 100, so that the negative electrodes of each battery cell 100 are connected in parallel.

[0082] Optionally, the battery cell may be a lithium battery structure. In one embodiment of the present disclosure, the battery cell has a first diaphragm, a negative electrode sheet, a second diaphragm, a positive electrode sheet, a negative electrode ear disposed on the negative electrode sheet, and a positive electrode ear disposed on the positive electrode sheet, which are stacked in sequence. In order to increase the capacity of the battery cell, the electrode sheets (positive electrode sheet, negative electrode sheet) and diaphragms (first diaphragm, second diaphragm) of the battery cell may be wound to form a rigid energy storage unit.

[0083] Alternatively, see Figure 3 The positive electrode tab 102 and the negative electrode tab 103 can be bent to the surface of the battery cell 100 (close to or away from the surface of the first flexible packaging layer F100) so as to be electrically connected to the flexible conductive layer 200. In one embodiment of the present disclosure, the flexible conductive layer 200 is disposed between the first flexible packaging layer F100 and the battery cell 100, and extends outside the flexible packaging structure along the first direction H1.

[0084] Optionally, in some embodiments, the spacing between two adjacent battery cells (the size of the spacing between two adjacent battery cells in the first direction) is not less than the thickness of the battery cell (the size between the upper and lower surfaces of the battery cell). In this way, the flexible battery can maintain greater flexibility. Of course, in other embodiments of the present disclosure, the spacing between two adjacent battery cells may also be less than the thickness of the battery cell.

[0085] In the related art, when the flexible battery is bent, stress concentration is prone to occur in the peripheral area BB. Specifically, stress concentration is prone to occur at the intersection of the extension line of the bending area A2 and the peripheral area BB, which in turn causes microcracks in the flexible packaging structure FES at this position. The microcracks may cause the flexible battery to fail, such as leakage, swelling, and bulging, and may cause safety hazards.

[0086] In the related art, since the size of microcracks is very small, the microcrack defects are often difficult to detect, especially cannot be quickly observed by naked eyes, which will lead to certain safety risks in flexible batteries.

[0087] In some embodiments of the present disclosure, see Figure 6 In order to efficiently detect microcracks at the edge of the flexible packaging structure FES, the flexible battery may be provided with a crack detection trace PCD. The crack detection trace PCD may be located in the peripheral area BB and at least partially extend along the first direction H1; wherein the crack detection trace PCD is enclosed in the flexible packaging structure FES. In this embodiment, when microcracks occur at the crack detection trace PCD position of the flexible packaging structure FES, the microcracks will damage the crack detection trace PCD, for example, causing the resistance of the crack detection trace PCD to increase at the microcrack (local rupture or thinning, etc., resulting in increased resistance) or rupture. Therefore, it is possible to determine whether microcracks exist by detecting the electrical state of the crack detection trace PCD (such as resistance size or whether it is open circuit).

[0088] In these embodiments, the crack detection trace PCD is covered and protected by the flexible packaging structure FES. In this way, the electrical state of the crack detection trace PCD is consistent with the state of the flexible packaging structure FES in the peripheral area BB, thereby improving the accuracy of crack detection. In the embodiments of the present disclosure, it is avoided to set the crack detection trace PCD outside the flexible packaging structure FES. If the crack detection trace PCD is set outside the flexible packaging structure FES, when non-microcrack factors cause the crack detection trace PCD to break, for example, when the crack detection trace PCD is corroded or scratched, the change in the electrical state of the crack detection trace PCD is inconsistent with the state of the flexible packaging structure FES; this is not conducive to accurately detecting microcracks in the flexible packaging structure FES.

[0089] Alternatively, see Figure 7 The crack detection trace PCD may be located in the first flexible packaging layer F100. In this way, the first flexible packaging layer F100 may provide protection for the crack detection trace PCD to prevent the crack detection trace PCD from being exposed to the outside and being scratched or corroded.

[0090] In one embodiment of the present disclosure, the crack detection line PCD can be located between the second adhesive layer F104 and the first protective layer F105. In this way, the crack detection line PCD can be protected by the first protective layer F105, and is insulated from the first metal layer F103 by the second adhesive layer F104. In addition, a film layer such as the first metal layer F103 is provided between the crack detection line PCD and the first heat sealing layer F101, thereby avoiding the influence of the melting and deformation of the first heat sealing layer F101 during heat sealing on the crack detection line PCD.

[0091] In some embodiments, see Figure 8 , the end of the crack detection trace PCD may be electrically connected to a crack detection pad (Pad1, Pad2), and the crack detection pad (Pad1, Pad2) is used to be electrically connected to an external circuit (such as a circuit board 300) so that the external circuit can detect whether the crack detection trace PCD is broken or damaged. In one embodiment of the present disclosure, the crack detection pad (Pad1, Pad2) may be directly connected to the end of the crack detection trace PCD. Of course, in other embodiments of the present disclosure, the crack detection pad may not be directly connected to the crack detection trace, but may be transferred through other conductive traces; that is, the crack detection pad and the crack detection trace may be indirectly connected through other conductive traces.

[0092] In some embodiments, the crack detection trace PCD may converge to one side of the flexible conductive layer 200 and extend to the binding area; the crack detection pad may be provided in the binding area. In this way, the various pads connected to the flexible battery and the outside can be brought together to improve the degree of integration and facilitate connection with the external circuit. Of course, in other embodiments of the present disclosure, the crack detection pad may be provided in the binding area, and the crack detection trace may not converge to the binding area, but may be electrically connected to the crack detection pad through other conductive traces connected to the binding area.

[0093] See also Figure 2 , the peripheral area BB may include a first peripheral area B1, a third peripheral area B3, a second peripheral area B2 and a fourth peripheral area B4 connected end to end in sequence. The first peripheral area B1 and the second peripheral area B2 are located on both sides of the battery area AA, and both extend along the first direction H1. The third peripheral area B3 and the fourth peripheral area B4 are located on both sides of the battery area AA, and both extend along the second direction H2. The second direction H2 is the extension direction of the battery cell 100. Furthermore, the first direction H1 is perpendicular to the second direction H2.

[0094] In one embodiment of the present disclosure, see Figure 6 , the crack detection trace PCD includes a first sub-detection trace PCD1 and a second sub-detection trace PCD2 which are electrically connected to each other; the first sub-detection trace PCD1 runs through the first peripheral area B1 along the first direction H1, and the second sub-detection trace PCD2 runs through the second peripheral area B2 along the first direction H1. When the flexible battery is bent, stress concentration easily occurs in the first peripheral area B1 and the second peripheral area B2, resulting in microcracks. In this embodiment, the crack detection trace PCD runs through the first peripheral area B1 and the second peripheral area B2 along the first direction H1, so microcracks in the first peripheral area B1 and the second peripheral area B2 can be effectively detected.

[0095] Furthermore, the crack detection trace PCD also includes a third sub-detection trace PCD3 that runs through the third peripheral area B3, and the third sub-detection trace PCD3 connects the first sub-detection trace PCD1 and the second sub-detection trace PCD2. In this way, the crack detection trace PCD can also detect microcracks located in the third peripheral area B3.

[0096] Of course, it can be understood that, in some embodiments, the crack detection trace PCD may further include a fourth detection sub-trace located in the fourth peripheral area B4 so as to detect microcracks located in the fourth peripheral area B4.

[0097] Optionally, the number of crack detection traces PCD may be one or more.

[0098] Optionally, the thickness of the crack detection trace PCD is in the range of 0.3 to 1.5 micrometers. The required crack detection trace PCD can be formed by printing, vapor deposition, magnetron sputtering, etc.

[0099] Optionally, the material of the crack detection trace PCD may be a metal material, which may include a metal layer or a plurality of stacked metal layers. For example, in one embodiment of the present disclosure, the crack detection trace PCD includes a titanium layer, an aluminum layer, and a titanium layer stacked in sequence. Of course, in other embodiments of the present disclosure, the crack detection trace PCD may also be made of other conductive materials, such as organic conductive materials or conductive metal oxides.

[0100] Optionally, the width of the crack detection line PCD is in the range of 0.2 to 1.0 mm; further, the width of the crack detection line PCD is in the range of 0.4 to 0.7 mm. Exemplarily, the width of the crack detection line PCD is 0.5 mm.

[0101] Optionally, the distance between the crack detection trace PCD and the edge of the flexible packaging structure FES is in the range of 0.5 to 1.5 mm. In this way, the crack detection trace PCD is set close to the edge of the flexible packaging structure FES, so as to timely reflect the micro-cracks at the edge of the flexible packaging structure FES. Furthermore, the distance between the crack detection trace PCD and the edge of the flexible packaging structure FES is in the range of 0.8 to 1.0 mm. Exemplarily, in one embodiment of the present disclosure, the distance between the crack detection trace PCD and the edge of the flexible packaging structure FES is 0.93 mm.

[0102] The present disclosure may also provide an external circuit connected to the flexible battery, for example, a circuit board. Figure 8The circuit board 300 includes a resistance detection circuit 310. The resistance detection circuit 310 is used to be electrically connected to the crack detection trace PCD of the flexible battery, and is configured to detect the resistance of the crack detection trace PCD. In this way, it can be determined whether there are microcracks on the edge of the flexible battery based on the resistance of the crack detection trace PCD.

[0103] Furthermore, the circuit board 300 may also include a bootstrap circuit 320. The bootstrap circuit 320 is used to be electrically connected to the crack detection trace PCD, and is configured to receive a first voltage and output a second voltage to the crack detection trace; the second voltage is higher than the first voltage. In this way, the bootstrap circuit 320 can output a higher voltage signal to the crack detection trace to accelerate the resistance change of the crack detection trace PCD at the microcrack, thereby improving the sensitivity of microcrack detection. Specifically, when microcracks appear at the edge of the flexible battery, the crack detection trace PCD at this position will become fragile and the resistance will increase; when a high voltage signal passes through, the heat generated by the crack detection trace PCD at this position will be higher than other positions, thereby accelerating the fracture of the crack detection trace PCD at this position.

[0104] Furthermore, the bootstrap circuit 320 may generate a high voltage pulse signal with a peak voltage being a second voltage, thereby generating a detection current on the crack detection trace PCD or burning the crack detection trace PCD at the crack.

[0105] See also Figure 8 The circuit board 300 may also include crack detection pins (Pin1, Pin2) for binding and connecting with the crack detection pads (Pad1, PAD2). In this way, the circuit board 300 can be electrically connected to the crack detection trace PCD, and then the resistance of the crack detection trace PCD can be detected, and whether microcracks are generated at the edge of the flexible battery can be determined based on the resistance of the crack detection trace PCD.

[0106] In one embodiment of the present disclosure, the bootstrap circuit 320 includes a boost subcircuit 321 and a logic control subcircuit 322. Fig. 9 , the boost sub-circuit 321 includes:

[0107] A first capacitor C1, two ends of which are connected to a first node N1 and a second node N2 respectively;

[0108] A first switch S1, one end of which is electrically connected to the first node N1, and the other end of which is used to load a reference voltage GND;

[0109] A second switch S2, one end of which is electrically connected to the second node N2, and the other end of which is connected to the input terminal Vin for loading the first voltage;

[0110] A third switch S3, one end of which is used to load the first voltage, and the other end of which is electrically connected to the first node N1;

[0111] A fourth switch S4, one end of which is connected to the second node N2, and the other end of which is connected to the output terminal Vout for outputting a second voltage;

[0112] The second capacitor C2 has one end for loading the reference voltage GND, and the other end connected to the output end Vout.

[0113] The logic control subcircuit 322 is used to control the on or off of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4. Specifically, the logic control subcircuit is configured to turn on the first switch S1 and the second switch S2, and turn off the third switch S3 and the fourth switch S4 during the charging stage. The logic control subcircuit 322 is also configured to turn off the first switch S1 and the second switch S2, and turn on the third switch S3 and the fourth switch S4 during the discharging stage.

[0114] In this embodiment, the working process of the bootstrap circuit 320 is as follows:

[0115] During the charging phase, see Fig.10 ,, the input terminal Vin is loaded with the first voltage V1. The first switch S1 and the second switch S2 are turned on, while the third switch S3 and the fourth switch S4 are turned off. At this time, at both ends of the first capacitor C1, the voltage of the first node N1 is 0V, and the voltage of the second node N2 is the first voltage V1. The potential difference between the second node N2 and the first node N1 is equal to the first voltage V1.

[0116] During the discharge phase, see Fig.11 , the input terminal Vin is loaded with the first voltage V1. The first switch S1 and the second switch S2 are closed, while the third switch S3 and the fourth switch S4 are opened. At this time, the voltage of the first node N1 is equal to the first voltage V1, and under the coupling effect of the first capacitor C1, the voltage of the second node N2 is bootstrapped to 2V1. The voltage of the second node N2 is output as the output voltage through the output terminal Vout. At this time, the voltage output by the output terminal Vout is the second voltage, and its magnitude is 2V1.

[0117] In some embodiments of the present disclosure, the risk of microcracks can be reduced by adjusting the flexible packaging structure FES. Figure 1, the first flexible encapsulation layer F100 may be a flat encapsulation layer. The second flexible encapsulation layer F200 may be a concave-convex encapsulation layer, which may include a convex portion F301 covering the battery cell 100, and a concave portion F302 located between adjacent battery cells 100. In this way, the flexible battery can be bent toward the concave-convex side. Among them, the elastic modulus of the first flexible encapsulation layer F100 may be greater than the elastic modulus of the second flexible encapsulation layer F200. In this way, by making the elastic modulus of the flat encapsulation layer larger, the neutral plane of the flexible encapsulation structure FES when bending can be adjusted so that the neutral plane is closer to the outer surface of the first flexible encapsulation layer F100 with a large elastic modulus. In this way, when bending, most of the flexible encapsulation structure FES is located on the side of the neutral layer close to the battery cell 100 and is subjected to compressive stress, and a small part of the flexible encapsulation structure FES is located on the side of the neutral layer away from the battery cell 100 and is subjected to tensile stress. For the part of the flexible encapsulation structure FES that is subjected to tensile stress, due to the offset of the neutral plane, the thickness of the part is small, so its tensile deformation is small. On the whole, the flexible packaging structure FES has a stronger tolerance to bending and is less likely to produce microcracks due to bending, which improves the bending resistance of the flexible battery.

[0118] The present invention conducts bending reliability tests (bending 50,000 times) on three different flexible batteries.

[0119] In the first flexible battery, the first flexible encapsulation layer F100 uses a flexible encapsulation layer with a high elastic modulus, and the second flexible encapsulation layer F200 also uses a flexible encapsulation layer with a high elastic modulus. The results show that the flexible encapsulation structure FES of the first flexible battery has creases at the bending position. This indicates that the first flexible battery has damage at the edge and cannot pass the bending reliability test.

[0120] In the second flexible battery, the first flexible encapsulation layer F100 uses a flexible encapsulation layer with a low elastic modulus, and the second flexible encapsulation layer F200 also uses a flexible encapsulation layer with a low elastic modulus. The results show that the flexible encapsulation structure FES of the second flexible battery has creases at the bending position. This indicates that the second flexible battery has damage at the edge and cannot pass the bending reliability test.

[0121] In the third flexible battery, the first flexible encapsulation layer F100 uses a flexible encapsulation layer with a high elastic modulus, and the second flexible encapsulation layer F200 uses a flexible encapsulation layer with a low elastic modulus. The results show that no creases are generated at the edge of the third flexible battery. This indicates that the flexible battery of the embodiment of the present disclosure has passed the bending reliability test, and the risk of microcracks is very low.

[0122] Optionally, the elastic modulus of the first metal layer may be greater than the elastic modulus of the second metal layer, thereby making the elastic modulus of the first flexible encapsulation layer F100 greater than the elastic modulus of the second flexible encapsulation layer F200.

[0123] Optionally, the elastic modulus of the first flexible encapsulation layer F100 is 6 to 11 times the elastic modulus of the second flexible encapsulation layer F200. In this way, the neutral plane of the flexible encapsulation structure FES can be effectively adjusted, thereby improving the bending reliability of the flexible battery.

[0124] In one embodiment of the present disclosure, the elastic modulus of the first flexible encapsulation layer F100 is in the range of 180 GPa to 220 GPa. Further, the first flexible encapsulation layer F100 is a steel plastic film. Exemplarily, the first metal layer F103 may be a stainless steel layer, for example, 304 stainless steel. It is understood that the first flexible encapsulation layer F100 may also be other flexible encapsulation layers with a high elastic modulus.

[0125] In one embodiment of the present disclosure, the Poisson's ratio of the first flexible encapsulation layer F100 may be between 0.35 and 0.45, for example, between 0.39 and 0.41.

[0126] In one embodiment of the present disclosure, the thickness of the first flexible encapsulation layer F100 may be between 40 and 60 micrometers, for example, between 45 and 55 micrometers.

[0127] In one embodiment of the present disclosure, the elastic modulus of the second flexible encapsulation layer F200 is in the range of 20 GPa to 30 GPa. Further, the second flexible encapsulation layer F200 is an aluminum-plastic film. Exemplarily, the second metal layer F203 may be an aluminum foil layer. It is understood that the second flexible encapsulation layer F200 may also be other flexible encapsulation layers with a low elastic modulus.

[0128] In one embodiment of the present disclosure, the Poisson's ratio of the second flexible encapsulation layer F200 may be between 0.35 and 0.45, for example, between 0.39 and 0.41.

[0129] In one embodiment of the present disclosure, the thickness of the second flexible encapsulation layer F200 may be between 40 and 60 micrometers, for example, between 45 and 55 micrometers.

[0130] The present disclosure also provides an electronic device, which includes any one of the flexible batteries described in the above flexible battery embodiments. The electronic device may be a smart watch, a smart phone, or other types of electronic devices; in particular, the electronic device may be a flexible portable electronic device, such as a flexible wearable device. Since the electronic device has any one of the flexible batteries described in the above flexible battery embodiments, it has the same beneficial effects, and the present disclosure will not be repeated here.

[0131] In one embodiment of the present disclosure, the electronic device further includes a display panel, and the flexible battery is used to supply power to the display panel.

[0132] In a further embodiment, the display panel is a flexible display panel. Thus, the electronic device uses a flexible battery and a flexible display panel, so that the electronic device as a whole is bendable.

[0133] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A flexible battery, comprising: A flexible packaging structure, comprising a battery area and a peripheral area surrounding the battery area; the battery area comprises a plurality of rigid areas and a plurality of bending areas alternately arranged along a first direction; A plurality of battery cells are arranged corresponding to the plurality of rigid regions one by one; in the corresponding rigid regions, the battery cells are enclosed in the flexible packaging structure; a crack detection line located in the peripheral area and extending at least partially along the first direction; wherein the crack detection line is enclosed in the flexible packaging structure; Wherein, the flexible packaging structure comprises a first flexible packaging layer and a second flexible packaging layer which are stacked; the battery cell is arranged between the first flexible packaging layer and the second flexible packaging layer; The second flexible packaging layer is an aluminum-plastic film; Along the direction away from the battery core, the first flexible packaging layer includes a first heat sealing layer, a first adhesive layer, a first metal layer, a second adhesive layer and a first protective layer stacked in sequence; The crack detection wiring is sandwiched between the second adhesive layer and the first protective layer; The flexible battery further comprises a flexible conductive layer, wherein the flexible conductive layer is at least partially encapsulated in the flexible packaging structure and is electrically connected to each of the battery cells; The flexible conductive layer has a binding area located outside the flexible packaging structure; the binding area has a crack detection pad electrically connected to the crack detection trace.

2. The flexible battery according to claim 1, wherein: The peripheral area includes a first peripheral area and a second peripheral area located on both sides of the battery area; the first peripheral area and the second peripheral area both extend along the first direction; The crack detection line includes a first sub-detection line and a second sub-detection line electrically connected to each other; the first sub-detection line runs through the first peripheral area along the first direction, and the second sub-detection line runs through the second peripheral area along the first direction.

3. The flexible battery according to claim 2, wherein: The peripheral area further includes a third peripheral area, the third peripheral area connecting the first peripheral area and the second peripheral area; The crack detection line further includes a third sub-detection line that passes through the third peripheral area, and the third sub-detection line connects the first sub-detection line and the second sub-detection line.

4. The flexible battery according to claim 1, wherein: The thickness of the crack detection line is in the range of 0.3 to 1.5 microns.

5. The flexible battery according to claim 1, wherein: The width of the crack detection line is in the range of 0.2 to 1.0 mm.

6. The flexible battery according to claim 1, wherein: The distance between the crack detection line and the edge of the flexible packaging structure is in the range of 0.5 to 1.5 mm.

7. The flexible battery according to claim 1, wherein: The material of the crack detection wiring is metal material.

8. The flexible battery according to claim 1, wherein: The battery cells are arranged on one side of the first flexible packaging layer and are spaced apart along the first direction; The second flexible packaging layer includes a protruding portion covering the battery cells, and includes a recessed portion located between adjacent battery cells.

9. The flexible battery according to claim 1, wherein: The elastic modulus of the first flexible encapsulation layer is greater than the elastic modulus of the second flexible encapsulation layer.

10. The flexible battery according to claim 1, wherein: The first flexible packaging layer is a steel-plastic film.

11. A circuit board, comprising: A resistance detection circuit, used to be electrically connected to the crack detection trace of the flexible battery according to any one of claims 1 to 10, and configured to detect the resistance of the crack detection trace; a bootstrap circuit, used to be electrically connected to the crack detection trace, and configured to receive a first voltage and output a second voltage to the crack detection trace; The second voltage is higher than the first voltage; Wherein, the bootstrap circuit includes a voltage boost subcircuit and a logic control subcircuit; The boost subcircuit comprises: A first capacitor, two ends of which are connected to a first node and a second node respectively; A first switch, one end of which is electrically connected to the first node, and the other end of which is used to load a reference voltage; a second switch, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the input terminal; a third switch, one end of which is electrically connected to the input end, and the other end of which is electrically connected to the first node; a fourth switch, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the output end; A second capacitor, one end of which is electrically connected to the output end, and the other end of which is used to load the reference voltage; The logic control subcircuit is configured to turn on the first switch and the second switch and turn off the third switch and the fourth switch during a charging phase; the logic control subcircuit is also configured to turn off the first switch and the second switch and turn on the third switch and the fourth switch during a discharging phase.

12. An electronic device comprising the flexible battery according to any one of claims 1 to 10.

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