TWI639270B - Flexible battery - Google Patents

Abstract

The present invention relates to a flexible battery in which an electrochemical reaction structure system is directly bonded to an inner surface of a package structure by a polymer having a mercapto group, an imide group and a carbonyl group, and thus a linear polymer is conventionally known. Compared with the main polymer system, the electrochemical reaction structure disclosed in the present invention and the collector layer in the package structure can have better adhesion, and since the collector layer in the present invention is the package structure In some cases, therefore, the electrochemical reaction structure is replaced with a chemical bond between the package structure and a general physical fixing method, for example, vacuum coating, so that the battery is not easily separated from each other after bending. In order to improve the structural stability and safety of the battery.

Description

Flexible battery

The present invention relates to a flexible battery, and more particularly to a flexible battery that avoids bending and causes separation of the electrochemical reaction structure from the package structure.

Recently, various electronic devices have been created correspondingly. In order to make the electronic device more in line with the trend of thinness and lightness, space allocation in the electronic device has become an important issue, and a non-planar flexible battery can be solved for this problem. One of the strategies. However, in the process of bending, once the electrochemical reaction layer is peeled off from the collector layer, the destruction of the battery structure and safety problems are caused.

In terms of the characteristics of the battery, if the active material layer and the collector layer have better adhesion, the moving distance between the electron and the ion in the electrode layer can be effectively shortened, and the resistance inside the electrode layer is lowered, and the electrochemical is improved. Conversion efficiency. In more detail, when the active material layer and the collector layer are tightly bonded, the distance between electrons and ions migrates is shortened, and the interface between the layers is hindered from being lowered, thereby improving the coulombic efficiency and causing the battery to be charged and discharged after repeated charging. The capacity can still be maintained. In addition, the selection of the adhesive in the active material layer can not only significantly affect the adhesion state between the layers, but also directly determine the content and distribution of the active material in the active material layer, with the connection of the active material and the adhesive. The better the relationship, the better the active material content and arrangement in the active material layer, and of course the battery capacity can be increased.

As mentioned above, at present, in general lithium batteries, such as polyvinyl difluoroethylene (PVDF), polyvinylidene fluoride-co-trichloroethylene (PVDF-HFP), styrene butadiene rubber (styrene- Butadiene; SBR) and other highly flexible adhesives, which are structurally linear and therefore provide a relatively good adhesion in the XY axial direction, but the adhesive is heat treated or laminated. After the treatment, the polymer chain is crystallized by the influence of heat and pressure, in other words, the active material layer to which the above adhesive is added, At the interface between the collector layers, the adhesion at the interface is affected by the generation of crystallization after heat treatment or pressing treatment. In addition, since the structure or crystal structure of the adhesive itself is destroyed by external force, the activity is lowered. The adhesion ability of the material, so that the pole layer is prone to cracks after drying, and even the separation of the active material layer and the collector layer occurs, eventually leading to a decrease in electron conductivity, which is more serious except that the electrical efficiency of the battery is deteriorated. Affect the safety of the battery. On the other hand, if an adhesive having a three-dimensional structure such as Epoxy, Acrylic Acid, or polyacrylonitrile (PAN) is used in its entirety, the adhesion effect can be improved, but the polymer is used. The three-dimensional structure itself causes problems of excessive rigidity and insufficient flexibility, and it is difficult to achieve the requirement of battery bending.

In view of the above, the present invention has been directed to the absence of the above-described prior art and proposes a flexible battery to effectively overcome the above problems.

The main object of the present invention is to provide a flexible battery which utilizes a polymer of a mercapto group, an imido group and a carbonyl group to provide a high molecular bonding force and improve the electrochemical reaction structure and the collector layer. The weaker molecular bonding can avoid the collapse or separation of the electrochemical reaction structure and the collector layer after the flexible battery is bent, and ensure that the electronic conductivity of the flexible battery can be maintained after bending. status.

Another main object of the present invention is to provide a flexible battery which is disclosed in the contact surface of the electrochemical reaction structure and the package structure, which must contain a certain amount of the first high at the interface end of the electrochemical reaction structure. Molecules, and the first polymer accounts for 0.02 wt.% to 70 wt.% of the polymer system.

Another object of the present invention is to provide a flexible battery which uses a collector layer as a part of a package structure to bond the entire package structure and the electrochemical reaction structure into a single structure, so that the package is packaged. The interface between the structure and the electrochemical reaction structure is replaced by a general chemical bonding method by direct chemical bonding, so that the formed flexible battery can increase the degree of bending and the number of times.

A further object of the present invention is to provide a flexible battery by adding a polymer containing a mercapto group, an imido group and a carbonyl group to reduce the linear polymer alignment by a lattice specification after a hot process or a hot press process. A situation in which high crystallization occurs.

It is still another object of the present invention to provide a flexible battery which improves the resistance of an overall flexible battery to thermal energy by adding a polymer containing a mercapto group, an imine group and a carbonyl group, thereby enabling the flexible battery to The heat treatment temperature that can be withstood during the hot or hot press can be greater than 180 °C.

Still another object of the present invention is to provide a flexible battery in which the polymer containing a mercapto group, an imido group and a carbonyl group is not a linear polymer.

In order to achieve the above object, the present invention provides a flexible battery comprising a package structure and an electrochemical reaction structure directly adhered to the package structure, characterized by an electrochemical reaction structure and a package structure. At least one of the surfaces is directly bonded by the first polymer, wherein the first polymer has a mercaptoamine group, an imido group and a carbonyl group, and the first polymer accounts for 0.02% by weight of the polymer system. Wt.%~70wt.%. Therefore, compared with the conventional polymer system mainly based on a linear polymer, the electrochemical reaction structure and the package structure disclosed in the present invention can have better adhesion, so that the battery is less likely to cause the structures to be mutually bent after being bent. The separation is to improve the structural stability and safety of the battery.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

1‧‧‧Flexible battery

2‧‧‧Package structure

221‧‧‧ Collecting substrate

222‧‧‧ Collecting substrate

24‧‧‧ plastic frame

4‧‧‧Electrochemical reaction structure

421‧‧‧Active material layer

422‧‧‧Active material layer

44‧‧‧Electrical insulation

S‧‧‧Enclosed space

S _up ‧‧‧ inner surface

S _down ‧‧‧ inner surface

S _side ‧‧‧ side circumference

Fig. 1 is a schematic structural view showing an embodiment of a flexible battery of the present invention.

Please refer to Figure 1 first. The flexible battery 1 comprises an electrochemical reaction structure 4 and a package structure 2, and the package structure 2 is a sealed structure, and the aspect thereof may be a bag body, a box body or a shape of any container, and the package structure 2 includes There are two collector substrates 221, 222 and a plastic frame 24, the collector substrates 221, 222 are correspondingly arranged, and the plastic frame 24 is in the front projection direction along the periphery of at least one of the collector substrates 221 or 222 And disposed at the same time, directly or indirectly bonded to the two current collecting substrates 221 and 222, so that the plastic frame 24 is sandwiched between the two current collecting substrates 221 and 222 and the two current collecting substrates 221 and 222 are bonded to each other. According to the above configuration, in the region formed by the frame 24 and the two collector substrates 221 and 222, a sealing region is formed. Therefore, the inside of the package structure 2 has two inner surfaces S _up and S. _Down and a surrounding space S, wherein the top and bottom of the enclosed space S are the above two inner surfaces S _up and S _down , and the side periphery S _{side of} the enclosed space S is a partial plastic frame 24, It may for example be the inner edge surface of the plastic frame 24.

The inner surfaces S _up and S _down of the package structure 2 are part of the surfaces of the collector substrates 221 and 222, and their functions are for collecting the electrochemical reaction structure 4 . Since the plastic frame 24 must be able to completely seal the side periphery S _{side of the} package structure 2, the frame 24 is a continuous structure or a discontinuous structure without a break.

The electrochemical reaction structure 4 has a polymer system including a first polymer, and the first polymer is included at the interface between the electrochemical reaction structure 4 and the package structure 2, for example. When the interface between the electrochemical reaction structure 4 and the package structure 2 is an active material in the electrochemical reaction system, the first polymer is blended in the active material to form the active material layers 421, 422, for example: A positive electrode active material layer or a negative electrode active material layer. In addition, when the flexible battery 1 has a separate electrically insulating layer 44, the first polymer may also be blended therein as one of the adhesives in the electrically insulating layer 44, and the electrical insulation described herein. Layer 44 is, for example but not limited to, a ceramic barrier layer, a polymeric barrier layer, a nonwoven barrier layer, or a combination of the foregoing.

In a specific battery chemical system, such as a liquid electrolyte chemical system, the material of the frame is recommended to have a material that is opposite or repellent to the polarity of the electrolyte, such as silicone, acrylic or epoxy. The colloidal material can thereby repel the electrolyte by the characteristics of the material of the frame itself when the electrolyte is injected, and avoid the problem that the adhesiveness of the frame is deteriorated due to the contamination of the electrolyte.

Continuing, and in various battery systems, the invention can also be divided into applications in liquid battery systems, colloidal battery systems, and solid state battery systems, for example, for liquid battery systems and colloidal battery systems, The first polymer is mainly used in an electrical insulating layer as an adhesive, and for a colloidal battery system and a solid battery system, the first polymer in the polymer system can be applied not only to the electrical insulating layer. (especially colloidal battery systems and solids that specifically use the barrier layer Battery system), the more important application is the electrolyte in the colloidal battery system and the solid-state battery system, by adding the first polymer to increase the speed of ion movement in the electrolyte, thereby enhancing the colloidal electrolyte and the solid electrolyte. Ion conductivity.

Of course, taking all the above-mentioned aspects as an example, according to the characteristics and effects of different active materials, ceramic materials or polymer materials, in addition to the first polymer, in various battery systems, each of the electrochemical reaction structures The first polymer can be formulated in the same ratio or in different proportions to the other polymer to achieve the best effect, but most importantly, as shown in Fig. 1, in the package structure 2 On the contact surface (for example, the inner surfaces S _up , S _down ), the interface end of the electrochemical reaction structure 4 must contain a certain amount of the first polymer.

The first polymer disclosed in the present invention has a mercaptoamine group, an imido group and a carbonyl group, and the first polymer accounts for 0.02 wt.% to 70 wt.% of the polymer system, and the linear polymer In contrast, the first polymer is not classified as a linear polymer. In terms of structure, the first polymer is more similar to a branched polymer, a crosslinked polymer, a network polymer, a ladder polymer or the above polymer. a derivative, so for a polymer system in which a linear polymer and a first polymer are mixed, the amide group, the imine group, and the carbonyl group of the first polymer can make the molecules of the electrochemical reaction structure and the encapsulated structure The bonding force is increased. In more detail, the polymer system of the electrochemical reaction structure layer may include, in addition to the conventional linear polymer, for example, but not limited to, polyvinylidene fluoride (PVDF). The first polymer of the amide group, the imine group, and the carbonyl group may be, for example, but not limited to, a ladder polymer. Here, polyimide (PI) is exemplified. Therefore, when referring to FIG. 1 , when the electrochemical reaction structure 4 and the two current collector substrates 221 and 222 of the package structure 2 are to be bonded, the current collecting substrates 221 and 222 are metal substrates, and The metal may be, for example but not limited to, copper, aluminum, nickel, stainless steel, etc., on the bonding interface (internal surface S _up , S _down ) of the electrochemical reaction structure 4 and the collector substrates 221, 222 (for example, copper foil, aluminum foil) In addition to the molecular bonding of the fluorine atom of the linear polymer (for example, PVDF) to the current collecting substrates 221 and 222, the nitrogen atom and the guanamine bond of the ladder-like polymer are generated by the presence of the first polymer. The imine bond and the carbonyl bond have a positive and significant influence on the adhesion between the electrochemical reaction structure 4 and the collector substrates 221 and 222 in the package structure 2. Further, the above polyimide (PI) or a derivative thereof comprises a thermosetting polyimine, a thermoplastic polyimide or a mixture of the above materials.

Although the above description is based on a specific material, in reality, the linear polymer is characterized by being composed of a linear polymer having a certain degree of softness. Therefore, the material of the linear polymer may be selected from polydifluorocarbon. Polyvinylidene fluoride; PVDF, PVDF-HFP, Polytetrafluoroethene (PTFE), Acrylic Acid, Epoxy , polyoxyethylene (PEO), polyacrylonitrile (PAN), carboxymethyl cellulose (CMC), styrene-butadiene (SBR), polymethylacrylate ), polyacrylamide, polyvinylpyrrolidone (PVP), and combinations thereof.

Further, although the first polymer described above is a ladder-shaped polymer, when the first polymer is composed of a branched polymer, a crosslinked polymer, or a network polymer, the polymer material which can be referred to is selected. From epoxy resin (Epoxy), Acrylic Acid, polyacrylonitrile (PAN) and combinations thereof.

Further, in addition to the above-described first polymer mainly composed of a branched polymer, a crosslinked polymer, a network polymer or a ladder polymer, the adhesion of the electrochemical reaction structure 4 to the package structure 2 is improved. In addition, it is equally important that the flexible battery 1 disclosed in the present invention directly bonds the electrochemical reaction structure 4 to the package structure 2, in other words, the connection between the electrochemical reaction structure 4 and the package structure 2. The relationship is a chemical bond, and the collector substrates 221 and 222 are part of the package structure 2, compared with a conventional battery (not shown), and the conventional electrochemical reaction structure is also The current collecting substrate is bonded, but the packaging material is not integrated into the single structure of the current collecting substrate. Therefore, the connection relationship between the electrochemical reaction structure and the packaging material bonded to the current collecting substrate is achieved by vacuuming. The purpose of fixing the overall flexible battery structure, but obviously, since the structure of the flexible battery is only fixed in a vacuum manner in the conventional flexible battery structure, if the package state is not good, the bending angle is too large, and the number of bending times is excessive Under the influence of other factors, it is easy to damage the vacuum state of the packaging material. Responding to the electrical performance and safety requirements of the battery, and at the same time, the appearance of the battery will also produce significant wrinkles and breakage. In contrast, the flexible battery 1 disclosed in the present invention is directly bonded to the electrochemical reaction structure 4 The current collecting substrates 221 and 222 in the package structure 2 are bonded to the past physical connection by chemical bonding, and are mixed with a linear polymer or a branched polymer as compared with a polymer system containing a linear polymer alone. The polymer system of crosslinked polymer, network polymer or ladder polymer can provide stronger chemical molecular bonding force, and the bonding effect of the electrochemical reaction structure 4 and the package structure 2 is greatly improved.

In addition, the bonding between the electrochemical reaction structure and the package structure disclosed in the present invention can be performed by directly forming the electrochemical reaction structure directly on the package structure, and the electrochemical reaction structure can also be thermally processed. The pressing process or the hot pressing process is bonded to the package structure, but regardless of the bonding mode, if the polymer system in the electrochemical reaction structure is to be chemically bonded to the inner surface of the package structure, the electrochemical reaction Both the structure and the package structure must be subjected to a thermal process, a press process or a hot press process to enable the polymer material of the polymer system to be matured, and compared with the conventional polymer system, the conventional polymer system system Mainly linear polymers, so the curing temperature is usually low (usually 120 ~ 150 ° C), but because the polymer system of the present invention contains a nonlinear polymer, the heating temperature of the hot process can be increased to 150 °C, and the preferred heating temperature is between 180 and 220 ° C; in addition, in addition to the hot polymer process to cure the polymer system, the pressing process can be carried out simultaneously, wherein the pressing process The pressure value can be between 40 and 120 kilograms (kgf), and the preferred pressure value is between 65 and 110 kilograms (kgf); of course, depending on the material properties, the thermal process and the compression process are also Can be integrated into a single hot press, the temperature and pressure conditions are still the same as the above range.

In addition, another second polymer is further included in the electrochemical reaction structure, and the weight percentage of the second polymer in the polymer system of the electrochemical reaction structure is between 0.02 wt.% and 70 wt.%. Similar to the first polymer described above, the second polymer is not a linear polymer, but is mainly a branched polymer, a crosslinked polymer, a network polymer, a ladder polymer, a derivative of the above polymer or the above A combination of various materials, for example, the material of the second polymer is selected from epoxy resin (Epoxy), Acrylic acid, polyacrylonitrile (PAN) and combinations thereof, or ladder polymers selected from polyimide (PI) and derivatives thereof, wherein polyimine (polyimide, PI) and its derivatives may be thermosetting polyimine, thermoplastic polyimide or a mixture of the above.

When the first polymer and the second polymer are simultaneously included in the polymer system of the electrochemical reaction structure, since the first polymer and the second polymer are not linear polymers, they are different according to different electrochemical systems ( For example, the type of active material, the isolation system, etc., the first polymer and the second polymer in the polymer system may be the same polymer material, but the first polymer and the second polymer account for the weight of the polymer system. The percentages are not necessarily the same. Of course, the first polymer and the second polymer may also be different polymer materials, and the weight percentage of the two is not limited. Further, the conditions of the thermal processing and the press-bonding process of the second polymer are also the same as those of the first polymer described above.

Finally, all the structures, all materials and all processes disclosed in the present invention are applicable to various battery systems, for example, liquid batteries, colloidal batteries, solid batteries, liquid/colloidal hybrid batteries, liquid/solid hybrid batteries. Or a colloidal/solid-state hybrid battery, or a so-called flexible lithium battery, a flexible lithium ion battery, a flexible lithium polymer battery, a flexible lithium metal battery, a flexible lithium ceramic battery, or a flexible lithium cermet battery.

The above description is only for the preferred embodiment of the invention and is not intended to limit the scope of the invention. Therefore, any changes or modifications of the features and spirits of the present invention should be included in the scope of the present invention.

Claims (25)

A flexible battery comprising: an electrochemical reaction structure having a polymer system comprising a first polymer; and a package structure sealed to have two inner surfaces and one inside a surrounding space directly bonded to the electrochemical reaction structure, the enclosing space for accommodating the electrochemical reaction structure; characterized in that the electrochemical reaction structure and the package structure At least one of the inner surfaces is directly bonded by the first polymer, wherein the first polymer has a guanamine group, an imine group and a carbonyl group, and the first polymer occupies the polymer system The weight percentage is between 0.02 wt.% and 70 wt.%. The flexible battery of claim 1, wherein the inner surfaces collect current from the electrochemical reaction structure. The flexible battery of claim 1, wherein the package structure comprises: two collector substrates disposed correspondingly to each other; and a plastic frame attached to the periphery of at least one of the collector substrates in a right projection direction And the plastic frame is simultaneously bonded to the current collecting substrate, the plastic frame is sandwiched between the two current collecting substrates, and the two current collecting substrates are bonded to each other, and the plastic frame and the current collector are assembled. The substrate is sealed to enclose the enclosed space. The flexible battery of claim 3, wherein the top and bottom of the enclosed space are two inner surfaces, and the side periphery of the enclosed space is a portion of the plastic frame. The flexible battery of claim 3, wherein the electrochemical reaction structure is directly or indirectly connected to the plastic frame. The flexible battery of claim 3, wherein the plastic frame is a closed continuous structure or a discontinuous structure without a break. The flexible battery of claim 1, wherein the electrochemical reaction structure is formed directly on the inner surface of the package structure. The flexible battery according to claim 1, wherein the electrochemical reaction structure and the inner surface of the package structure are further cooked by the thermal process to the first polymer. The electrochemical reaction structure is adhered to the package structure. The flexible battery according to claim 8, wherein the heating temperature of the hot process is between 150 and 250 ° C, and the preferred heating temperature is between 180 and 220 ° C. The flexible battery according to claim 1, wherein the electrochemical reaction structure and the inner surface of the package structure are further bonded to the package structure by a pressing process. The flexible battery of claim 10, wherein the pressure value of the pressing process is between 40 and 120 kilograms (kgf), and the preferred pressure value is between 65 and 110 kilograms (kgf). The flexible battery according to claim 1, wherein the polymer system further comprises a linear polymer selected from the group consisting of polydifluoroethylene, polyvinylidene fluoride-co-trichloroethylene, and poly Tetrafluoroethylene, acrylic acid, epoxy resin, polyethylene oxide, polyacrylonitrile, sodium carboxymethyl cellulose, styrene butadiene rubber, polymethyl acrylate, polyacrylamide, polyvinylpyrrolidone and combinations thereof . The flexible battery according to claim 1, wherein the first polymer is not a linear polymer. The flexible battery according to claim 1, wherein the first polymer is selected from the group consisting of a branched polymer and a derivative thereof, a crosslinked polymer and a derivative thereof, a network polymer and a derivative thereof, and a ladder-like high Molecules and their derivatives and combinations thereof. The flexible battery according to claim 14, wherein the material of the first polymer is a network polymer selected from the group consisting of epoxy resin, acrylic resin, polyacrylonitrile, and the combination thereof. The flexible battery according to claim 14, wherein the first polymer is a ladder polymer of polyimine and a derivative thereof. The flexible battery according to claim 14, wherein the first polymer is a polyimine and a derivative thereof, and comprises a thermosetting polyimide, a thermoplastic polyimide or a mixture of the above materials. The flexible battery according to claim 1, wherein the electrochemical reaction structure further comprises another second polymer, wherein the second polymer accounts for 0.02 wt.% to 70 wt% of the polymer system. %. The flexible battery of claim 18, wherein the second polymer is not a linear polymer. The flexible battery according to claim 18, wherein the second polymer is selected from the group consisting of a branched polymer and a derivative thereof, a crosslinked polymer and a derivative thereof, a network polymer and a derivative thereof, and a ladder shape. Polymers and their derivatives and combinations thereof. The flexible battery according to claim 20, wherein the material of the second polymer is a network polymer selected from the group consisting of epoxy resins, acrylic resins, polyacrylonitriles, and combinations thereof. The flexible battery according to claim 20, wherein the second polymer is a ladder polymer of polyimine and a derivative thereof. The flexible battery according to claim 22, wherein the second polymer is a polyimine and a derivative thereof, and comprises a thermosetting polyimide, a thermoplastic polyimide or a mixture of the above materials. The flexible battery according to claim 1 is a liquid battery, a colloidal battery, a solid battery, a liquid/colloidal hybrid battery, a liquid/solid hybrid battery or a colloidal/solid hybrid battery. The flexible battery according to claim 1 is a flexible lithium battery, a flexible lithium ion battery, a flexible lithium polymer battery, a flexible lithium metal battery, a flexible lithium ceramic battery or a flexible lithium cermet battery.