Patent Publication Number: US-2023163430-A1

Title: Connecting member, flexible battery, electronic device, and manufacturing method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/CN2021/125643, filed on Oct. 22, 2021, which claims priority to China Patent Application No. 202011444771.1 filed on Dec. 11, 2020, the disclosure of both of which are incorporated by reference herein in entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a connecting member for a flexible battery, a flexible battery, an electronic device and a manufacturing method. 
     BACKGROUND 
     With the increasing demand for smart devices and electronic products, a series of products such as flexible electronic devices, wearable electronic devices, implantable biomedical systems, repairable biomedical systems, and electric vehicles are widely used, which inspires the unremitting pursuit for high-performance batteries having high energy density, shape diversity, deformation diversity and favorable mechanical properties. 
     SUMMARY 
     According to an aspect of embodiments of the present disclosure, a connecting member for a flexible battery is provided. The connecting member comprises: a first polymer layer; a flexible conductive layer on a surface of the first polymer layer, wherein the flexible conductive layer is in direct contact with the first polymer layer; a bonding layer on a side of the flexible conductive layer away from the first polymer layer; and a second polymer layer on a side of the bonding layer away from the flexible conductive layer. 
     In some embodiments, the flexible conductive layer is connected to a tab for an energy storage member, and the bonding layer covers at least a portion of the tab. 
     In some embodiments, a material of the flexible conductive layer comprises: at least one of metal, conductive polymer or non-conductive polymer with a treated metal surface. 
     In some embodiments, materials of the first polymer layer and the second polymer layer each comprise: at least one of polyimide, polyethylene terephthalate or polyvinylidene chloride. 
     In some embodiments, the bonding layer comprises: at least one of natural rubber, synthetic rubber, thermoplastic elastomer, polyacrylate, polyurethane, polyvinyl chloride or polyvinyl ether. 
     In some embodiments, the flexible conductive layer comprises: a first flexible conductive layer and a second flexible conductive layer spaced apart from the first flexible conductive layer. 
     According to another aspect of the embodiments of the present disclosure, a flexible battery is provided. The flexible battery comprises: the connecting member described above; and a plurality of energy storage members located on the connecting member, and electrically connected to the connecting member. 
     In some embodiments, the connecting member comprises a first flexible conductive layer and a second flexible conductive layer spaced apart from the first flexible conductive layer; and each of the plurality of energy storage members comprises a positive electrode tab and a negative electrode tab, wherein the positive electrode tab is connected to the first flexible conductive layer, and the negative electrode tab is connected to the second flexible conductive layer. 
     In some embodiments, extending directions of any two energy storage members of the plurality of energy storage members are parallel; an extending direction of the first flexible conductive layer is parallel to an extending direction of the second flexible conductive layer; and the extending direction of the first flexible conductive layer is perpendicular to an extending direction of any one of the plurality of energy storage members. 
     In some embodiments, the plurality of energy storage members are arranged at equal intervals along the extending direction of the first flexible conductive layer, and the first flexible conductive layer and the second flexible conductive layer are arranged along the extending direction of any one of the plurality of energy storage members. 
     In some embodiments, the flexible battery further comprises: a conductive member connected to the flexible conductive layer of the connecting member. 
     In some embodiments, the flexible battery further comprises: an encapsulation layer surrounding the connecting member and the plurality of energy storage members. 
     According to another aspect of embodiments of the present disclosure, an electronic device is provided. The electronic device comprises the flexible battery described above. 
     According to another aspect of the embodiments of the present disclosure, a manufacturing method of a connecting member for a flexible battery is provided. The manufacturing method comprises: forming a flexible conductive layer on a surface of a first polymer layer, wherein the flexible conductive layer is in direct contact with the first polymer layer; and adhering a second polymer layer to a side of the flexible conductive layer away from the first polymer layer by a bonding layer. 
     In some embodiments, the flexible conductive layer is formed on a surface of the first polymer layer by a deposition process. 
     In some embodiments, the deposition process comprises: at least one of a thermal evaporation process, a magnetron sputtering process, chemical vapor deposition, atomic layer deposition, electrodeposition, a spraying process, a chemical plating process, a spin coating method or a dip pulling method. 
     In some embodiments, the manufacturing method further comprises: welding a tab for an energy storage member on the flexible conductive layer before adhering the second polymer layer to the side of the flexible conductive layer away from the first polymer layer. 
     Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       The accompanying drawings which constitute part of this specification, illustrate the exemplary embodiments of the present disclosure, and together with this specification, serve to explain the principles of the present disclosure. 
       The present disclosure may be more explicitly understood from the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a schematic cross-sectional view showing a connecting member for a flexible battery according to an embodiment of the present disclosure; 
         FIG.  2    is a top view showing a connecting member for a flexible battery according to an embodiment of the present disclosure; 
         FIG.  3    is a top view showing a connecting member for a flexible battery according to another embodiment of the present disclosure; 
         FIG.  4    is a schematic cross-sectional view showing a connecting member for a flexible battery according to another embodiment of the present disclosure; 
         FIG.  5 A  is a top view showing a flexible battery according to an embodiment of the present disclosure; 
         FIG.  5 B  is a side view showing a flexible battery according to an embodiment of the present disclosure; 
         FIG.  5 C  is an enlarged schematic view showing a structure at block  301  of  FIG.  5 A ; 
         FIG.  5 D  is an enlarged schematic view showing a structure at block  302  of  FIG.  5 B ; 
         FIG.  6 A  is a top view showing a flexible battery according to another embodiment of the present disclosure; 
         FIG.  6 B  is a bottom view showing a flexible battery according to another embodiment of the present disclosure; 
         FIG.  6 C  is a schematic structural view showing an energy storage member of a flexible battery according to an embodiment of the present disclosure; 
         FIG.  7 A  is a top view showing a flexible battery according to another embodiment of the present disclosure; 
         FIG.  7 B  is a bottom view showing a flexible battery according to another embodiment of the present disclosure; 
         FIG.  8    is a flowchart showing a manufacturing method of a connecting member for a flexible battery according to an embodiment of the present disclosure; 
         FIG.  9 A  is a schematic cross-sectional view showing a structure at a stage during a manufacturing process of a connecting member for a flexible battery according to an embodiment of the present disclosure; 
         FIG.  9 B  is a schematic cross-sectional view showing a structure at another stage during a manufacturing process of a connecting member for a flexible battery according to an embodiment of the present disclosure; 
         FIG.  10 A  is a view showing a fatigue life test result of a connecting member for a flexible battery in the related art; 
         FIG.  10 B  is a view showing a fatigue life test result of a connecting member for a flexible battery according to an embodiment of the present disclosure. 
     
    
    
     It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn according to the actual scale. In addition, the same or similar reference signs are used to denote the same or similar components. 
     DETAILED DESCRIPTION 
     Various exemplary embodiments of the present disclosure will now be described in detail in conjunction with the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended as a limitation to the present disclosure, its application or use. The present disclosure may be implemented in many different forms, which are not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art. It should be noticed that: relative arrangement of components and steps, material composition, numerical expressions, and numerical values set forth in these embodiments, unless specifically stated otherwise, should be explained as merely illustrative, and not as a limitation. 
     The use of the terms “first”, “second” and similar words in the present disclosure do not denote any order, quantity or importance, but are merely used to distinguish between different parts. A word such as “comprise”, “include”, or the like means that the element before the word covers the element(s) listed after the word without excluding the possibility of also covering other elements. The terms “up”, “down”, “left”, “right”, or the like are used only to represent a relative positional relationship, and the relative positional relationship may be changed correspondingly if the absolute position of the described object changes. 
     In the present disclosure, when it is described that a particular device is located between the first device and the second device, there may be an intermediate device between the particular device and the first device or the second device, and alternatively, there may be no intermediate device. When it is described that a particular device is connected to other devices, the particular device may be directly connected to said other devices without an intermediate device, and alternatively, may not be directly connected to said other devices but with an intermediate device. 
     All the terms (comprising technical and scientific terms) used in the present disclosure have the same meanings as understood by those skilled in the art of the present disclosure unless otherwise defined. It should also be understood that terms as defined in general dictionaries, unless explicitly defined herein, should be interpreted as having meanings that are consistent with their meanings in the context of the relevant art, and not to be interpreted in an idealized or extremely formalized sense. 
     Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, these techniques, methods, and apparatuses should be considered as part of this specification. 
     For a flexible lithium battery, its key technical core is to obtain a favorable flexibility on the basis of maintaining the electrochemical property of traditional lithium batteries. It is a technical solution to realize a flexible battery by decoupling the energy storage unit and the flexible portion of a lithium battery. The battery may be separated into a rigid energy storage member and a flexible connecting member. Rigid energy storage members are connected by flexible connecting members. The flexibility of the battery is achieved by bending the flexible connecting member. 
     For example, a bamboo-shaped battery is an implementation solution to realize a flexible battery by decoupling the energy storage member and the flexible connecting member of the lithium battery. A structure of the bamboo-shaped battery comprises a plurality of energy storage members, which are connected by flexible connecting members. The energy storage member is compatible with the structure, material and process of traditional rigid lithium-ion batteries; and the flexible connecting member may be realized by adopting a diaphragm and an encapsulating material in a body structure of the lithium-ion battery or introducing a new flexible connection material such as a flexible circuit board or a flexible composite layer. The bamboo-shaped battery based on the decoupling of the energy storage member and the flexible connecting member of the lithium battery may be applied to a flexible product required to be bent, folded, or even twisted in shape, for example, a flexible bracelet, curled display, folded display, or the like. 
     In the related art, for a flexible battery (for example, a bamboo-shaped battery) comprising an energy storage member and a flexible connecting member, the flexible connecting member is a composite film structure formed by bonding the polymer film layer on the upper and lower sides of the flexible conductor layer through the adhesive material layer. That is, in the flexible connecting member of the related art, the upper and lower sides of the flexible conductor layer are attached with the polymer film layer through the adhesive material layer respectively. However, the inventors of the present disclosure have found that, the flexible connecting member of the flexible battery in the related art has a relatively short fatigue life. Here, the fatigue life refers to maximum bending times that can be achieved by the flexible connecting member before fracture during repeated bending tests under the condition of a certain bending radius. 
     In view of this, the embodiments of the present disclosure provide a connecting member for a flexible battery to improve the fatigue life of the connecting member. 
       FIG.  1    is a schematic cross-sectional view showing a connecting member for a flexible battery according to an embodiment of the present disclosure. 
     As shown in  FIG.  1   , the connecting member comprises a first polymer layer  101 . In some embodiments, the first polymer layer  101  is a polymer film layer. For example, a material of the first polymer layer comprises: at least one of polyimide, polyethylene terephthalate or polyvinylidene chloride. 
     As shown in  FIG.  1   , the connecting member further comprises a flexible conductive layer  110  on a surface of the first polymer layer  101 . The flexible conductive layer  110  is in direct contact with the first polymer layer  101 . For example, a material of the flexible conductive layer  110  comprises: at least one of metal, conductive polymer or non-conductive polymer with a treated metal surface. For example, the metal comprises at least one of stainless steel, aluminum, nickel, titanium, copper, or aluminum-cadmium alloy. For example, the stainless steel is a surface treated stainless steel with carbon, nickel, titanium, silver, gold, platinum, or the like. The flexible conductive layer is configured to realize the electrical connection between energy storage members of the flexible battery. 
     As shown in  FIG.  1   , the connecting member further comprises a bonding layer  120  on a side of the flexible conductive layer  110  away from the first polymer layer  101 . In some embodiments, the bonding layer  120  is an adhesive layer. For example, the bonding layer  120  comprises: at least one of natural rubber, synthetic rubber, thermoplastic elastomer, polyacrylate, polyurethane, polyvinyl chloride or polyvinyl ether. 
     As shown in  FIG.  1   , the connecting member further comprises a second polymer layer  102  on a side of the bonding layer  120  away from the flexible conductive layer  110 . In some embodiments, the second polymer layer  102  is a polymer film layer. For example, a material of the second polymer layer  102  comprises: at least one of polyimide, polyethylene terephthalate or polyvinylidene chloride. 
     So far, a connecting member for a flexible battery according to some embodiments of the present disclosure is provided. The connecting member is a flexible connecting member. The connecting member comprises: a first polymer layer; a flexible conductive layer on a surface of the first polymer layer, wherein the flexible conductive layer is in direct contact with the first polymer layer; a bonding layer on a side of the flexible conductive layer away from the first polymer layer; and a second polymer layer on a side of the bonding layer away from the flexible conductive layer. In the connecting member of the present disclosure, a lower surface of the flexible conductive layer is in direct contact with the first polymer layer. In the flexible connecting member of the related art, a lower surface of the flexible conductor layer is attached with a polymer film layer through an adhesive material layer. Therefore, compared with the flexible connecting member of the related art, the connecting member of the present disclosure reduces the number of contact interfaces, which can reduce the risk of peeling-off of the interfaces between different layers, thereby improving the fatigue life of the connecting member. 
       FIG.  2    is a top view showing a connecting member for a flexible battery according to an embodiment of the present disclosure. 
     It should be noted that, for the ease of illustration, the bonding layer  120  and the second polymer layer  102  are not shown in  FIG.  2   . However, those skilled in the art can understand that, as a matter of fact, the connecting member shown in  FIG.  2    comprises the bonding layer  120  and the second polymer layer  102 . 
     In some embodiments, as shown in  FIG.  2   , the flexible conductive layer  110  of the connecting member is connected with a conductive member  130 . The conductive member  130  can be used as a total tab to be electrically connected to another device (not shown in  FIG.  2   ). 
     In the connecting member shown in  FIG.  2   , the flexible conductive layer  110  may be connected to a positive electrode tab or a negative electrode tab of an energy storage member. In this way, the connection between the flexible conductive layer and the energy storage member is achieved. 
     So far, a connecting member for a flexible battery according to other embodiments of the present disclosure is provided. In the connecting member, the flexible conductive layer is an integral flexible conductive layer, and the flexible conductive layer is connected with a conductive member serving as a total tab. The conductive member may serve as part of the flexible battery manufactured and formed using the connecting member. 
       FIG.  3    is a top view showing a connecting member for a flexible battery according to another embodiment of the present disclosure. 
     It should be noted that, for the ease of illustration, the bonding layer  120  and the second polymer layer  102  are not shown in  FIG.  3   . However, those skilled in the art can understand that, as a matter of fact, the connecting member shown in  FIG.  3    comprises the bonding layer  120  and the second polymer layer  102 . 
     In some embodiments, as shown in  FIG.  3   , the flexible conductive layer  110  comprises: a first flexible conductive layer  111  and a second flexible conductive layer  112  spaced apart from the first flexible conductive layer  111 . For example, the first flexible conductive layer  111  and the second flexible conductive layer  112  are separated by the second polymer layer  102  (not shown in  FIG.  3   ). For example, the first flexible conductive layer may be configured to connect a positive electrode tab of an energy storage member (to be described later), and the second flexible conductive layer may be configured to connect a negative electrode tab of the energy storage member. In this way, the connection of the connecting member and the energy storage member is achieved. 
     In some embodiments, the flexible conductive layer  100  of the connecting member is connected with a conductive member. For example, the conductive member comprises a first conductive member  131  connected to the first flexible conductive layer  111  and a second conductive member  132  connected to the second flexible conductive layer  112 . Here, the first conductive member may serve as a first total tab, and the second conductive member may serve as a second total tab. 
     So far, a connecting member for a flexible battery according to other embodiments of the present disclosure is provided. In the connecting member, the flexible conductive layer comprises a first flexible conductive layer and a second flexible conductive layer, wherein the first flexible conductive layer is connected with a first conductive member, and the second flexible conductive layer is connected with a second conductive member. The first conductive member and the second conductive member may be part of a flexible battery manufactured and formed using the connecting member. 
       FIG.  4    is a schematic cross-sectional view showing a connecting member for a flexible battery according to another embodiment of the present disclosure. For example,  FIG.  4    may be a schematic cross-sectional view of a structure of a connecting member in  FIG.  6 B  taken along the line A-A′. 
     Similar to the connecting member shown in  FIG.  1   , the connecting member shown in  FIG.  4    comprises the first polymer layer  101 , the flexible conductive layer  110 , the bonding layer  120  and the second polymer layer  102 . 
     In some embodiments, as shown in  FIG.  4   , the flexible conductive layer  110  is connected to a tab  140  for an energy storage member. For example, the tab  140  may be welded on the flexible conductive layer  110 . The bonding layer  120  covers at least a portion of the tab  140 . In this way, the electrical connection between different energy storage members and the connecting member is achieved. 
       FIG.  5 A  is a top view showing a flexible battery according to an embodiment of the present disclosure.  FIG.  5 B  is a side view showing a flexible battery according to an embodiment of the present disclosure.  FIG.  5 C  is an enlarged schematic view showing a structure at block  301  of  FIG.  5 A .  FIG.  5 D  is an enlarged schematic view showing a structure at block  302  of  FIG.  5 B . 
     As shown in  FIGS.  5 A to  5 D , the flexible battery may comprise a connecting member  200  and a plurality of energy storage members  210 . The plurality of energy storage members  210  are located on the connecting member  200 , and electrically connected to the connecting member  200 . For example, the connecting member  200  is the connecting member as described above. Each energy storage member  210  can be connected to the connecting member  200  through a tab. The specific connection condition can be referred to as shown in  FIG.  6 A  to  FIG.  6 B . 
     In some embodiments, as shown in  FIG.  5 B , the flexible battery further comprises an encapsulation layer  250  surrounding the connecting member  200  and the plurality of energy storage members  210 . It should be noted that, for the ease of illustrating other structures, the encapsulation layer  250  is not shown in  FIGS.  5 A,  5 C and  5 D . 
       FIG.  6 A  is a top view showing a flexible battery according to another embodiment of the present disclosure.  FIG.  6 B  is a bottom view showing a flexible battery according to another embodiment of the present disclosure.  FIG.  6 C  is a schematic structural view showing an energy storage member of a flexible battery according to an embodiment of the present disclosure. 
     It should be noted that, for the ease of illustration, the bonding layer  120  and the first polymer layer  101  are not shown in  FIGS.  6 A and  6 B . However, those skilled in the art can understand that, as a matter of fact, the connecting member as shown in  FIGS.  6 A and  6 B  comprises the bonding layer  120  and the first polymer layer  101 .  FIG.  6 A  shows a front side of the flexible battery, and  FIG.  6 B  shows a back side of the flexible battery opposite to the front side. 
     In some embodiments, as shown in  FIGS.  6 A and  6 B , the connecting member  200  comprises a first flexible conductive layer  111  and a second flexible conductive layer  112  spaced apart from the first flexible conductive layer  111 . As shown in  FIG.  6 C , each of the plurality of energy storage members  210  comprises a positive electrode tab  141  and a negative electrode tab  142 . The positive electrode tab  141  and the negative electrode tab  142  may be located at two opposite edge positions of the energy storage member  210  respectively. The positive electrode tab  141  is connected to the first flexible conductive layer  111 , and the negative electrode tab  142  is connected to the second flexible conductive layer  112 . For example, the positive electrode tabs  141  of all the energy storage members are connected to the first flexible conductive layer  111 , and the negative electrode tabs  142  of all the energy storage members are connected to the second flexible conductive layer  112 . In this way, the plurality of energy storage members can be connected to the same connecting member to form a flexible battery. 
     In some embodiments, as shown in  FIG.  6 A , extending directions  601  of any two energy storage members of the plurality of energy storage members  210  are parallel. An extending direction  602  of the first flexible conductive layer  111  is parallel to an extending direction  602  of the second flexible conductive layer  112 . In some embodiments, the extending direction  602  of the first flexible conductive layer  111  is perpendicular to the extending direction  601  of any one of the plurality of energy storage members  210 . 
     In some embodiments, as shown in  FIG.  6 A , the plurality of energy storage members  210  are arranged at equal intervals along the extending direction  602  of the first flexible conductive layer  111 , and the first flexible conductive layer  111  and the second flexible conductive layer  112  are arranged along the extending direction  601  of any one of the plurality of energy storage members  210 . Through the arrangement of the above-mentioned plurality of energy storage members, the flexible battery can be conveniently rolled up. 
     In some embodiments, the flexible battery further comprises a conductive member connected to the flexible conductive layer of the connecting member. For example, the conductive member comprises a first conductive member  131  connected to the first flexible conductive layer  111  and a second conductive member  132  connected to the second flexible conductive layer  112 . 
     So far, the flexible battery shown in  FIGS.  6 A to  6 B  is described, wherein the flexible battery comprises, for example, the connecting member, the plurality of energy storage members, and the conductive member as shown in  FIG.  3   . 
       FIG.  7 A  is a top view showing a flexible battery according to another embodiment of the present disclosure.  FIG.  7 B  is a bottom view showing a flexible battery according to another embodiment of the present disclosure.  FIG.  7 A  shows a front side of the flexible battery, and  FIG.  7 B  shows a back side of the flexible battery opposite to the front side. 
     As shown in  FIGS.  7 A and  7 B , the flexible battery comprises a connecting member, a plurality of energy storage members  210  electrically connected to the connecting member, and a conductive member  130  connected to a flexible conductive layer  110  of the connecting member. The connecting member may comprise a first connecting member  201  and a second connecting member  202  spaced from the first connecting member  201 . The first connecting member  201  and the second connecting member  202  may be, for example, the connecting members shown in  FIG.  2    respectively. 
     As shown in  FIG.  7 B , each energy storage member  210  comprises a positive electrode tab  141  and a negative electrode tab  142 . The positive electrode tab  141  is connected to the flexible conductive layer  110  (which may be referred to as a first flexible conductive layer) of the first connecting member  201 , and the negative electrode tab  142  is connected to the flexible conductive layer  110  (which may be referred to as a second flexible conductive layer) of the second connecting member  202 . In this way, the plurality of energy storage members can be connected to two spaced connecting members. 
     In some embodiments of the present disclosure, an electronic device is also provided. The electronic device comprises the flexible battery as previously described (for example, the flexible battery as shown in  FIG.  6 A or  7 A ). For example, the electronic device may be a flexible electronic device or a wearable electronic device or the like. 
       FIG.  8    is a flowchart showing a manufacturing method of a connecting member for a flexible battery according to an embodiment of the present disclosure. As shown in  FIG.  8   , the manufacturing method comprises steps S 802  to S 804 . 
     In step S 802 , a flexible conductive layer is formed on a surface of a first polymer layer. The flexible conductive layer is in direct contact with the first polymer layer. 
     In some embodiments, the flexible conductive layer is formed on the surface of the first polymer layer by a deposition process. For example, the deposition process comprises: at least one of a thermal evaporation process, a magnetron sputtering process, chemical vapor deposition, atomic layer deposition, electrodeposition, a spraying process, a chemical plating process, a spin coating method or a dip pulling method. 
     In step S 804 , a second polymer layer is adhered to a side of the flexible conductive layer away from the first polymer layer by a bonding layer. 
     So far, a manufacturing method of a connecting member for a flexible battery according to some embodiments of the present disclosure is provided. The manufacturing method comprises: forming a flexible conductive layer on a surface of a first polymer layer, wherein the flexible conductive layer is in direct contact with the first polymer layer; and adhering a second polymer layer to a side of the flexible conductive layer away from the first polymer layer by a bonding layer. Since the flexible conductive layer is directly formed on the surface of the first polymer layer in the above-described manufacturing method, compared with the flexible connecting member in the related art, the connecting member formed by the manufacturing method of the present disclosure can reduce the number of contact interfaces, which can reduce the risk of peeling-off of the interfaces between different layers, thereby improving the fatigue life of the connecting member. 
     Further, the flexible conductive layer is formed on the surface of the first polymer layer by the deposition process, which can enhance an adhesive force between the flexible conductive layer and the first polymer layer, thereby further improving the fatigue life of the connecting member. 
     In some embodiments, the manufacturing method further comprises: welding a tab for an energy storage member on the flexible conductive layer before adhering the second polymer layer to the side of the flexible conductive layer away from the first polymer layer. In this way, the electrical connection between the connecting member and the energy storage member may be achieved. 
       FIGS.  9 A and  9 B  are schematic cross-sectional views showing structures at several stages during a manufacturing process of a connecting member for a flexible battery according to an embodiment of the present disclosure. The manufacturing process of the connecting member for the flexible battery according to some embodiments of the present disclosure will be described in detail below in conjunction with  FIGS.  9 A to  9 B  and  FIG.  4   . 
     First, as shown in  FIG.  9 A , a flexible conductive layer  110  is formed on a first polymer layer  101  by a deposition process. 
     Next, as shown in  FIG.  9 B , a tab  140  for an energy storage member is welded on the flexible conductive layer  110 . For example, the tab  140  can be welded on the flexible conductive layer  110  by ultrasonic waves. 
     In some embodiments, a plurality of energy storage members may be arranged in parallel at equal intervals, and directions of a positive electrode tab and a negative electrode tab of each energy storage member coincide with each other respectively; all the positive electrode tabs are welded on one flexible conductive layer (for example, the first flexible conductive layer), and all the negative electrode tabs are welded on another flexible conductive layer (for example, the second flexible conductive layer). 
     In addition, a conductive member may also be welded on the flexible conductive layer. For example, a first conductive member is welded on the first flexible conductive layer, and a second conductive member is welded on the second flexible conductive layer. 
     Next, as shown in  FIG.  4   , the second polymer layer  102  is adhered to a side of the flexible conductive layer  110  away from the first polymer layer  101  by the bonding layer  120 . The bonding layer  102  covers at least a portion of the tab  140 . 
     So far, a manufacturing method of a connecting member for a flexible battery according to some embodiments of the present disclosure is provided. The manufacturing method can improve the fatigue life of the connecting member. 
     In some embodiments, the second polymer layer  102  may have through holes exposing the tabs. During the subsequent process of manufacturing the flexible battery, other portions of the plurality of energy storage members than the tabs may be provided on the connecting member (for example, by way of adhesion), so that the other portions of the plurality of energy storage members are connected to the tabs through the above-described through holes, thereby manufacturing a flexible battery. 
     In other embodiments, after the flexible conductive layer  110  is formed on the first polymer layer  101 , the second polymer layer  102  may also be adhered to a side of the flexible conductive layer  110  away from the first polymer layer  101  by the bonding layer  120 , wherein the second polymer layer has through holes exposing a portion of the flexible conductive layer. In this way, the connecting member is formed. Then, during the subsequent process of manufacturing a flexible battery, a plurality of energy storage members are provided on the connecting member, and the tabs of the plurality of energy storage members are connected to the flexible conductive layer through the above-described through holes. In this way, a flexible battery is formed. 
     In some embodiments, the process of manufacturing a flexible battery further comprises: connecting a conductive member to the flexible conductive layer of the connecting member, for example, by a welding process. 
     In some embodiments, the process of manufacturing a flexible battery further comprises: forming an encapsulation layer surrounding the connecting member and the plurality of energy storage members. 
       FIG.  10 A  is a view showing a fatigue life test result of a connecting member for a flexible battery in the related art. 
     The fatigue life test is performed on the flexible connecting member in the related art. For example, the flexible connecting member is bent with a bending radius of 15 millimeters (mm), a bending angle of 0 to 180°, and a cycle rate of 2.6 s/cycle, and voltage-current tests are performed under a constant current condition of 0.2 C. Here, each cycle means that the flexible connecting member is bent back and forth once. 
     It should be noted that, 0.2 C represents the charge/discharge multiplier of the flexible battery, which indicates the speed of the charge and discharge. The charge/discharge multiplier is a ratio of a charge/discharge current to a rated capacity. For example: when a battery with a rated capacity of 100 Ah (ampere hour) is discharged with a current of 20 A (ampere), its discharge multiplier is 0.2 C. When the discharge of the used capacity is completed in one hour, it is referred to as 1 C discharge; when the discharge of the used capacity is completed in five hours, it is referred to as 0.2 C discharge. 
     In the fatigue life test of the flexible connecting member, when the flexible connecting member is fractured, the test circuit will be open, which results in a voltage surge. Therefore, it can be determined whether the flexible connecting member is fractured by observing a variation condition of the test curve. As shown in  FIG.  10 A , the voltage surge in about 13 hours, and it is obtained by calculation that: 13×3600s/2.6 s=18K times. That is, the fatigue life of the flexible connecting member in the related art is about 18K times. 
       FIG.  10 B  is a view showing a fatigue life test result of a connecting member for a flexible battery according to an embodiment of the present disclosure. 
     Here, for the connecting member according to some embodiments of the present disclosure, the same test condition as the fatigue life test of the flexible connecting member in the related art is used. As shown in  FIG.  10 B , there is still no voltage surge occurring until 72.5 hours in the test, which indicates that the connecting member according to the embodiments of the present disclosure can still work without fracture at least until 72.5 hours, that is, bending for 100K times (i.e., 72.5×3600 s/2.6 s≈100K times). By comparing the test results shown in  FIGS.  10 A and  10 B , it can be seen that, compared with the flexible connecting member in the related art, the connecting member according to the embodiments of the present disclosure has a better fatigue life. 
     Hereto, various embodiments of the present disclosure have been described in detail. Some details well known in the art are not described in order to avoid obscuring the concept of the present disclosure. According to the above description, those skilled in the art would fully understand how to implement the technical solutions disclosed here. 
     Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for the purpose of illustration but not for limiting the scope of the present disclosure. It should be understood by those skilled in the art that modifications to the above embodiments or equivalently substitution of part of the technical features may be made without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.