CN105990610B - Flexible battery cell - Google Patents

Abstract

The present invention provides a flexible battery cell, which includes: a first pole piece, including a first current collector and a first active material layer; a second pole piece, including a second current collector and a second active material layer; a separator; and an electrolyte. The first current collector has a first peripheral blank area surrounding the first active material layer and not provided with the first active material layer; the second current collector has a second peripheral blank area surrounding the second active material layer and not provided with the second active material layer. The separator includes: an insulating layer; a first polyolefin layer bonded to one side of the insulating layer, facing the first active material layer; a second polyolefin layer bonded to the other side of the insulating layer, facing the second active material layer; the first peripheral blank area is bent and bonded to the first polyolefin layer; the second peripheral blank area is bent and bonded to the second polyolefin layer.

Description

Flexible battery

technical field

The invention relates to the field of energy storage devices, in particular to a flexible electric core.

Background technique

Due to the many advantages of lithium-ion batteries, such as high voltage, small size, light weight, high specific capacity, no memory effect, no pollution, small self-discharge and long cycle life, etc., its application in the field of mobile devices has been unprecedented. development, including mobile phones, video cameras, notebook computers, and other portable appliances. With the development of technology for mobile convenience devices and the increase in demand for them, the demand for secondary batteries as energy sources has increased dramatically. Among such secondary batteries, studies on lithium secondary batteries having high energy density and discharge voltage have been widely conducted, and are now widely used.

With the interest of consumers, electronic equipment tends to be smaller and thinner. In such battery designs, it is necessary to diversify the shape of the battery according to the shape of the device, and to efficiently use the internal space of the device, so many batteries need to be designed in a flexible manner.

The Chinese Patent Application Publication No. CN103247768A published on August 14, 2013 discloses a power supply unit and its ceramic isolation layer. The ceramic isolation layer is arranged between the first electrode substrate and the second electrode substrate. It is formed by adhering a plurality of ceramic particles by a double-adhesive system, which includes a linear polymer and a bridging polymer. The use of the ceramic separator is equivalent to a solid electrolyte, which can effectively prevent the short circuit caused by the contact of the positive and negative electrodes, but at the same time greatly reduces the kinetic performance of the battery, making it difficult for active ions to migrate back and forth; The reason is that ceramics are mainly metal oxides Al ₂ O ₃ , and it is difficult to form van der Waals force or effective chemical bonds with colloids, which will lead to the failure of the package. Therefore, ceramic components should be avoided in the package structure as adhesive layer.

The Chinese Patent Application Publication No. CN103187370A published on July 3, 2013 discloses a side package structure of an electronic module, which includes an upper substrate, a lower substrate and a sealing frame, and the sealing frame ring is set on the upper substrate The accommodating space is formed with the peripheral edge of the lower substrate, the upper substrate and the lower substrate, and the main body of the sealing frame is composed of a silica gel layer. However, affected by the flatness of the substrate, it is difficult to make the packaging interface tight no matter whether the silicone layer or other adhesive layer systems are used; and the use of the adhesive layer as the packaging material increases the material and manufacturing costs of the battery, which is not conducive to actual production and application.

Contents of the invention

In view of the problems existing in the background technology, the object of the present invention is to provide a flexible electric core, which can improve the packaging strength of the flexible electric core.

Another object of the present invention is to provide a flexible battery, which can increase the energy density of the flexible battery.

Another object of the present invention is to provide a flexible battery, which can improve the flexibility of the flexible battery.

In order to achieve the above object, the present invention provides a flexible electric core, which includes: a first pole piece, including a first current collector and a first active material layer disposed on only one surface of the first current collector; a second pole The sheet is opposite to the polarity of the first pole piece and stacked on top of each other, including a second current collector and a second active material layer disposed only on one surface of the second current collector opposite to the first current collector; the isolation film is located at Between the first pole piece and the second pole piece, covering and exceeding the first active material layer and the second active material layer; electrolyte solution. Wherein, the first current collector has a first peripheral blank area surrounding the first active material layer and not provided with the first active material layer; the second current collector has a first peripheral blank area surrounding the second active material layer and not provided with the second active material layer. The layer's second perimeter white space. The isolation film includes: an insulating layer; a first polyolefin layer bonded on one side of the insulating layer facing the first active material layer; and a second polyolefin layer bonded on the other side of the insulating layer facing the second active material layer. Two active material layers; wherein, the first peripheral blank area is bent and bonded to the first polyolefin layer of the separator; the second peripheral blank area is bent and bonded to the second polyolefin layer of the separator .

The beneficial effects of the present invention are as follows:

In the flexible electric core of the present invention, the first polyolefin layer and the second polyolefin layer of the separator are directly bonded to the first current collector and the second current collector respectively, and play a role in separating the first pole piece and the second pole piece. At the same time as the function of the dipole sheet, it is also used as the packaging material of the flexible electric core. Compared with the prior art, the packaging position of the present invention does not contain a ceramic layer, so that the isolation film can be combined with the first current collector and the second current collector. It is very firmly bonded together, and is not affected by the difference in flatness between the first current collector and the second current collector, because the lower the flatness of the first current collector and the second current collector, the lower the flatness of the first polyolefin layer and the first polyolefin layer respectively. The surface contact area of the polyolefin of the second polyolefin layer is larger and even forms a hook-shaped bond, which greatly improves the adhesion between objects and makes it more suitable for packaging flexible batteries, thereby improving the flexibility of flexible batteries. packaging strength. The higher the packaging strength, the lower the risk of liquid leakage, thereby improving the safety performance of the flexible battery. Because the first current collector and the second current collector are respectively bonded together with the first polyolefin layer and the second polyolefin layer to form a whole, the strength of the interface bond of the entire package of the flexible battery is greater, and the cohesion is also stronger. Strong, in other words, the external force needed to destroy this package structure needs to be greater, so the flexibility of the battery will be stronger. Because this packaging method is directly packaged with polyolefin substrate without adhesive tape, that is, it does not need to occupy the thickness space of the flexible battery, so its energy density is also higher. In the traditional gluing process, gluing needs to consider its positioning accuracy and control tolerance. From an engineering point of view, there is a great risk, and the efficiency will inevitably have a great impact. However, the present invention eliminates the The process of pasting glue is easier to realize in process. The invention directly uses the base material of the isolation film for packaging, without using other adhesive layers for packaging, effectively reduces the production material cost and manufacturing cost of the flexible battery, and is suitable for continuous production.

Description of drawings

Fig. 1 is a plan view of the first pole piece of the flexible battery according to the present invention during preparation;

Fig. 2 is a plan view of the first pole piece of the single flexible battery of Fig. 1;

Fig. 3 is a plan view of one side of the separator during preparation of the flexible battery according to the present invention;

Fig. 4 is a plan view of the isolation film of the single flexible battery of Fig. 3;

Fig. 5 is a plan view of the other side of the separator during the preparation of the flexible battery according to the present invention;

Fig. 6 is a plan view of the isolation film of the single flexible battery in Fig. 5;

Fig. 7 is a plan view of the second pole piece of the flexible battery according to the present invention during preparation;

Fig. 8 is a plan view of the second pole piece of the single flexible battery of Fig. 7;

Fig. 9 is a schematic diagram of the assembly of the flexible battery according to the present invention during preparation;

Fig. 10 is a sectional view of an embodiment of a flexible battery according to the present invention during preparation;

Fig. 11 is a sectional view of another embodiment of the flexible battery according to the present invention during preparation;

Fig. 12 is a sectional view of yet another embodiment of the flexible battery according to the present invention during preparation;

Fig. 13 is a sectional view of the flexible electric core of Fig. 7 after hot pressing during preparation and before cutting, in which three uncut flexible electric cores are shown;

Fig. 14 is a schematic perspective view of Fig. 13, showing three uncut flexible batteries;

Fig. 15 is a single flexible cell obtained in Fig. 14 .

Wherein, the reference signs are explained as follows:

1 First pole piece 3 Separator

11 First current collector 31 Insulation layer

111 First peripheral blank area 311 Microholes

12 first active material layer 32 first polyolefin layer

2 Second pole piece 33 Second polyolefin layer

21 Second Current Collector 34 First Coating Layer

211 Second perimeter blank area 35 Second coating layer

22 second active material layer

Detailed ways

The flexible battery cell according to the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIGS. 1 to 15 , the flexible battery cell according to the present invention includes: a first pole piece 1, including a first current collector 11 and a first active material layer 12 disposed only on one surface of the first current collector 11; The dipole sheet 2 is opposite in polarity to the first electrode sheet 1 and stacked on top of each other, including a second current collector 21 and a second active electrode disposed only on one surface of the second current collector 21 opposite to the first current collector 11 Material layer 22; separator 3, located between the first pole piece 1 and the second pole piece 2, and covering and exceeding the first active material layer 12 and the second active material layer 22; electrolyte (not shown, for Impregnation of the first active material layer 12, the second active material layer 22 and the separator 3). Wherein, the first current collector 11 has a first peripheral blank area 111 surrounding the first active material layer 12 and is not provided with the first active material layer 12; the second current collector 21 has a surrounding second active material layer 22 and is not provided A second peripheral blank area 211 is provided with the second active material layer 22 . Separator 3 includes: insulating layer 31; first polyolefin layer 32, bonded to one side of insulating layer 31, facing the first active material layer 12; and second polyolefin layer 33, bonded to the side of insulating layer 31 The other side faces the second active material layer 22; wherein, the first peripheral blank area 111 is bent and bonded with the first polyolefin layer 32 of the separator 3; the second peripheral blank area 211 is bent and bonded to the first polyolefin layer 32 of the separator 3; The second polyolefin layer 33 of the separator 3 is glued together.

In the flexible electric core of the present invention, the first polyolefin layer 32 and the second polyolefin layer 33 of the separator 3 are directly bonded to the first current collector 11 and the second current collector 21 respectively, and play a role in separating the first and second current collectors. While the role of the first pole piece 1 and the second pole piece 2, it is also used as the packaging material of the flexible electric core. Compared with the prior art, the packaging position of the present invention does not contain a ceramic layer, so the isolation film 3 can be combined with the second pole piece. The first current collector 11 and the second current collector 21 are very firmly bonded together, and are not affected by the difference in flatness between the first current collector 11 and the second current collector 21, because the first current collector 11 and the second current collector The lower the flatness of 21 is, the larger the surface contact area with the polyolefin of the first polyolefin layer 32 and the second polyolefin layer 33 is, and even a hook-shaped adhesive body is formed, which greatly improves the bonding force between objects, making It is more suitable for packaging flexible batteries, thereby improving the packaging strength of flexible batteries. The higher the packaging strength, the lower the risk of liquid leakage, thereby improving the safety performance of the flexible battery. Because the first current collector 11 and the second current collector 21 are respectively bonded together with the first polyolefin layer 32 and the second polyolefin layer 33 to form a whole, the strength of the interface bond of the entire package of the flexible electric core is greater , the cohesive force is also stronger, in other words, the external force needed to destroy this packaging structure needs to be greater, so the flexibility of the battery will be stronger. Because this packaging method is directly packaged with polyolefin substrate without adhesive tape, that is, it does not need to occupy the thickness space of the flexible battery, so its energy density is also higher. In the traditional gluing process, gluing needs to consider its positioning accuracy and control tolerance. From an engineering point of view, there is a great risk, and the efficiency will inevitably have a great impact. However, the present invention eliminates the The process of pasting glue is easier to realize in process. The invention directly uses the base material of the isolation film for packaging, without using other adhesive layers for packaging, effectively reduces the production material cost and manufacturing cost of the flexible battery, and is suitable for continuous production.

In an embodiment of the flexible battery cell according to the present invention, the electrolyte is a liquid electrolyte. Because the liquid electrolyte is filled in the gap of the active material of the pole piece, it does not occupy the thickness space of the flexible battery, so it has greater advantages in terms of kinetic performance, energy density and cost.

In one embodiment of the flexible electric core according to the present invention, referring to Fig. 1 and Fig. 2, Fig. 7 and Fig. 8, the size of the first current collector 11 and the second current collector 21 are the same; the distance between the first active material layer 12 and the second The distance between the edges of the surface of a current collector 11 is a ₁ , and a ₁ ≥ 4mm; the distance between the second active material layer 22 and the edges of the surface of the second current collector 21 is a ₂ , and a ₂ ≥ 4mm. a ₁ ≥ 4mm, a ₂ ≥ 4mm can ensure the packaging reliability and capacity of the flexible battery.

In an embodiment of the flexible electric core according to the present invention, referring to FIG. 10 to FIG. 13 , the dimensions of the first polyolefin layer 32, the second polyolefin layer 33 and the insulating layer 31 of the isolation film 3 are exactly the same and overlapped.

In an embodiment of the flexible electric core according to the present invention, the shape of the first active material layer 12 can be one of rectangle, circle and triangle; the shape of the second active material layer 22 can be rectangle, circle, One of the triangles.

In an embodiment of the flexible electric core according to the present invention, the first polyolefin layer 32 can be at least one of polyethylene, polypropylene, ethylene and propylene mixture; the second polyolefin layer 33 can be polyethylene, polypropylene At least one of propylene, ethylene and propylene mixtures.

In an embodiment of the flexible battery cell according to the present invention, the thickness of the first polyolefin layer 32 is ≥ 30 μm; the thickness of the second polyolefin layer 33 is ≥ 30 μm. When the thickness is less than 30 μm, the adhesive strength between the first polyolefin layer 32 and the first current collector 11 of the first pole piece 1 is insufficient, and the adhesion between the second polyolefin layer 33 and the second current collector 21 of the second pole piece 2 is insufficient. Insufficient connection strength affects the packaging reliability of flexible batteries.

In an embodiment of the flexible electric core according to the present invention, the material of the insulating layer 31 of the isolation film 3 can be polyamide (PI) and its composite, polyethylene terephthalate (PET) and its composite At least one of the materials, the material of the insulating layer 31 enables the isolation film 3 to combine the dual functions of insulation and high temperature resistance.

In an embodiment of the flexible electric core according to the present invention, referring to FIG. 12 , the insulating layer 31 of the isolation film 3 is on the first active material layer 12 of the corresponding first pole piece 1 and the second active material layer 12 of the second pole piece 2. Areas of the material layer 22 may be provided with through microholes 311 . The micropores 311 of the insulating layer 31 make the separator 3 beneficial to the penetration of the electrolyte and the transfer of lithium ions during the charge and discharge process of the flexible battery. When the material of the insulating layer 31 has high temperature resistance (such as the above-mentioned polyamide and its composite and/or polyethylene terephthalate and its composites), the micropores 311 of the insulating layer 31 further combine the dual functions of insulation and high temperature resistance.

In an embodiment of the flexible electric core according to the present invention, referring to Fig. 3, Fig. 4, Fig. 5, Fig. 6 and Fig. 9 to Fig. 13, the isolation film 3 may further include: a first coating layer 34 disposed The first polyolefin layer 32 of the film 3 is located within the scope of the first polyolefin layer 32, and correspondingly covers and exceeds the first active material layer 12; and the second coating layer 35 is arranged on the second side of the isolation film 3 On the polyolefin layer 33 and within the range of the second polyolefin layer 33, and correspondingly cover and exceed the second active material layer 22; wherein, the first peripheral blank area 111 is bent and connected to the first polyolefin layer of the isolation film 3 32 are bonded together; the second peripheral blank area 211 is bent and bonded with the second polyolefin layer 33 of the isolation film 3 . In one embodiment, the first coating layer 34 can be at least one of an inorganic particle coating, a polymer coating, and a mixed coating containing inorganic particles and a polymer; the second coating layer 35 can be an inorganic particle coating At least one of a layer, a polymer coating, and a hybrid coating containing inorganic particles and a polymer. Inorganic particles can effectively improve the thermal shrinkage of the separator, and the polymer can effectively improve the adhesion between the separator and the active material layer, thereby improving the heat resistance of the separator and the bonding strength of the interface.

In an embodiment of the flexible battery cell according to the present invention, the thickness of the first coating layer 34 may be 3 μm-20 μm; the thickness of the second coating layer 35 may be 3 μm-20 μm. When the thickness is less than 3 μm, the effective isolation and bonding effect between the active material in the active material layer and the separator 3 cannot be guaranteed, which affects the interface of the flexible battery. When the thickness is greater than 20 μm, it will affect the performance of the energy density of the flexible battery.

In an embodiment of the flexible electric core according to the present invention, with reference to FIGS. 3 and 4 and FIGS. 5 and 6 , the distance between the first coating layer 34 and each edge of the first polyolefin layer 32 of the isolation film 3 is d ₁ , and d ₁ ≥ 3 mm; the distance between the second coating layer 35 and each edge of the second polyolefin layer 33 of the isolation film 3 is d ₂ , and d ₂ ≥ 3 mm.

In an embodiment of the flexible electric core according to the present invention, the shape of the first coating layer 34 can be one of rectangle, circle and triangle corresponding to the shape of the first active material layer 12; the second coating layer The shape of 35 may be one of rectangle, circle and triangle corresponding to the shape of the second active material layer 22 .

The flexible battery cell of the present invention can be applied to watch straps, decorations, and wearable clothing, and is easy to carry and light.

Next, the preparation method of the flexible electric core according to the present invention is described, which is used to prepare the above-mentioned flexible electric core, which includes the steps: The first active material layer 12 and the second active material layer 22 are intermittently arranged on the opposite surface of the fluid 21 at a first predetermined distance b1 and a second predetermined distance b2, respectively, and the first current collector 11 has a structure surrounding the first active material layer 12. The first peripheral blank area 111 not provided with the first active material layer 12, the second current collector 21 has a second peripheral blank area 211 surrounding the second active material layer 22 without the second active material layer 22, stacked on top of each other The first pole piece 1 and the second pole piece 2 are not provided with the first active material layer 12 and the second active material layer 22 on the outer surface of the first current collector 11 and the second current collector 21 respectively (refer to FIG. 1 and Fig. 2, Fig. 3 and Fig. 4, Fig. 5 and Fig. 6 and Fig. 7 and Fig. 8); the first pole piece 1, the insulating layer 31 and the first pole piece bonded on the opposite sides of the insulating layer 31 Polyolefin layer 32 and the isolation film 3 of the second polyolefin layer 33, the second pole piece 2 are dried to remove water; On the first active material layer 12 and/or the second active material layer 22, spray electrolyte; The pole piece 1, the isolation film 3, and the second pole piece 2 are stacked on each other (refer to FIG. 9 and in conjunction with FIGS. 10 to 12);

The first peripheral blank area 111 on the surface of the first current collector 11 and the second peripheral blank area 211 on the surface of the second current collector 21 are respectively hot-pressed from the upper and lower sides, so that the first peripheral blank area 111 is bent And bond together with the first polyolefin layer 32 of the isolation film 3, and make the second peripheral blank area 211 bend and bond together with the second polyolefin layer 33 of the isolation film 3 (refer to FIG. 13 ), to Make a plurality of flexible electric cores (referring to Fig. 14); The positions where the second polyolefin layer 33 is bonded together correspond to vertical shearing, so as to make a single flexible battery (refer to FIG. 15 ).

In an embodiment of the preparation method of the flexible electric core according to the present invention, referring to Fig. 1 and Fig. 2, Fig. 7 and Fig. 8, the distance between the first active material layer 12 and each edge of the surface of the first current collector 11 is a ₁ , a ₁ ≥ 4mm; the distance between the second active material layer 22 and the edges of the surface of the second current collector 21 is a ₂ , and a ₂ ≥ 4mm; the first specified interval b1 is not less than 8mm; the second specified interval b2 is not Less than 8mm. a ₁ ≥ 4mm, a ₂ ≥ 4mm can effectively guarantee the seal width, ensure the reliability of the package, and eliminate the risk of short circuit and poor interface of the flexible battery; and the first specified distance b1 and the second specified distance b2 are not less than 8mm to protect The a ₁ ≥ 4mm and a ₂ ≥ 4mm of the single flexible cell obtained after cutting.

In an embodiment of the method for preparing a flexible battery according to the present invention, the drying temperature may be 60°C-120°C, and the drying time may be 4h-12h. Drying temperature and time are factors that affect each other. When the temperature and time are too low, water removal will not be sufficient, resulting in the failure of the flexible cell due to flatulence; when the temperature and time are too high, it will affect the performance of the active material in the active material layer. .

In an embodiment of the method for preparing a flexible battery according to the present invention, the humidity of drying and dehydration is not more than 2% RH. Controlling the humidity can prevent water vapor from entering the active material in the active material layer, and avoid the failure of the final flexible battery due to flatulence.

In an embodiment of the method for preparing a flexible battery cell according to the present invention, the amount of electrolyte sprayed may be 0.0020g/mAh-0.0030g/mAh. When the amount of electrolyte is less than 0.0020g/mAh, the dynamic performance of the flexible battery is reduced and it is difficult to exert sufficient capacity; when the amount of electrolyte is greater than 0.0030g/mAh, too much electrolyte will destroy the bonding of the interface To a certain extent, the flexibility of the flexible battery is reduced.

In an embodiment of the method for preparing a flexible electric core according to the present invention, the first pole piece 1, the separator 3 and the second pole piece 2 can be bonded together by hot pressing. In one embodiment, the temperature of the hot pressing may be 160°C-220°C, the pressure may be 0.2MPa-1MPa, and the time may be 1s-10s. Temperature, pressure and time are factors that affect each other. When the temperature, pressure and time are too low, the packaging effect of the packaging area is not good; when the temperature, pressure and time are too high, the isolation film 3 is easy to shrink, and there is a risk of short circuit. And the active material particles in the active material layer will fall off and affect the performance of the capacity.

In an embodiment of the method for preparing a flexible battery according to the present invention, the forming current is less than 0.1C. When the forming current is greater than 0.1C, the current density is not uniform, which will cause partial lithium deposition in the flexible battery and affect the capacity performance.

In an embodiment of the method for preparing a flexible electric core according to the present invention, the first polyolefin layer 32 of the separator 3 may be provided with: a first coating layer 34 located within the scope of the first polyolefin layer 32 and Correspondingly covering and exceeding the first active material layer 12 (refer to FIG. 3 and in conjunction with FIG. 8 to FIG. 10 ); the second polyolefin layer 33 of the isolation film 3 can be provided with: a second coating layer 35 located on the second polyolefin layer within the range of the layer 33 and correspondingly cover and exceed the second active material layer 22 (refer to FIG. 4 and in conjunction with FIG. 8 to FIG. 10 ); wherein, after hot pressing, the first peripheral blank area 111 is bent and aligned with the second active material layer of the isolation film 3 A polyolefin layer 32 is bonded together, and the second peripheral blank area 211 is bent and bonded together with the second polyolefin layer 33 of the isolation film 3 (refer to FIG. 11 ).

In an embodiment of the method for preparing a flexible battery cell according to the present invention, referring to FIG. 11 , the hot pressing adopts the back-shaped hot-pressing heads corresponding to the upper and lower sides, and the back-shaped hot-pressing heads on the upper side correspond to the hot-pressed front. The first peripheral blank area 111 of the back-type heat-pressed head corresponds to the second peripheral blank area 211 before heat-pressing. The width is not less than 2mm (in order to ensure the strength and reliability of the package), and the horizontal distance between the inner edge of the return-type head on the upper side and the lower side and the first coating layer 34 and the second coating layer 35 is not less than 1mm (In order to leave enough heat radiation area to prevent the active material in the active material layer from being affected by heat, resulting in the inability to effectively exert the capacity). Compared with the normal strip heat-pressed head, the return-shaped heat-pressed head can significantly improve the production efficiency.

In an embodiment of the method for preparing a flexible battery according to the present invention, referring to FIG. 3 and FIG. 4 , the first distance between adjacent first coating layers 34 is c _{1 ,} and c ₁ ≥ 6mm; The second distance between adjacent second coating layers 35 is c ₂ , and c ₂ ≥ 6mm. When c1 and c2<6mm, the single flexible cell obtained after cutting cannot guarantee the packaging reliability and capacity.

Claims (10)

1. A flexible electrical core comprising:

a first pole piece (1) comprising a first current collector (11) and a first active material layer (12) disposed on only one surface of the first current collector (11);

a second pole piece (2), opposite in polarity to the first pole piece (1) and superposed on each other, comprising a second current collector (21) and a second active material layer (22) provided only on one surface of the second current collector (21) opposite to the first current collector (11);

the isolation film (3) is positioned between the first pole piece (1) and the second pole piece (2) and covers and exceeds the first active material layer (12) and the second active material layer (22);

an electrolyte;

it is characterized in that the preparation method is characterized in that,

the first current collector (11) has a first peripheral blank region (111) surrounding the first active material layer (12) and not provided with the first active material layer (12);

the second current collector (21) has a second peripheral blank region (211) surrounding the second active material layer (22) and not provided with the second active material layer (22);

the separator (3) comprises:

an insulating layer (31);

a first polyolefin layer (32) adhered to one side of the insulating layer (31) to face the first active material layer (12); and

a second polyolefin layer (33) bonded to the other side of the insulating layer (31) facing the second active material layer (22);

wherein,

the first peripheral blank area (111) is bent and adhered with the first polyolefin layer (32) of the isolation film (3);

the second peripheral margin region (211) is folded and bonded to the second polyolefin layer (33) of the separator (3).

2. The flexible electrical core of claim 1,

the first current collector (11) and the second current collector (21) are the same in size;

the first active material layer (12) is at a distance a from each edge of the surface of the first current collector (11)₁And a is a₁≥4mm；

The distance between the second active material layer (22) and each edge of the surface of the second current collector (21) is a₂And a is a₂≥4mm。

3. The flexible electrical core of claim 1, wherein the first polyolefin layer (32), the second polyolefin layer (33), and the insulating layer (31) of the separator film (3) are of identical dimensions and overlap.

4. The flexible electrical core of claim 1,

the thickness of the first polyolefin layer (32) is more than or equal to 30 mu m;

the thickness of the second polyolefin layer (33) is not less than 30 μm.

5. The flexible electrical core according to claim 1, characterized in that the insulating layer (31) of the separator (3) is provided with through-going pores (311) in the regions corresponding to the first active material layer (12) of the first pole piece (1) and the second active material layer (22) of the second pole piece (2) that are adjacent.

6. The flexible electrical core of claim 1,

the separator (3) further comprises:

a first coating layer (34) which is arranged on the first polyolefin layer (32) of the isolation film (3) and is positioned in the range of the first polyolefin layer (32), and correspondingly covers and exceeds the first active material layer (12); and

a second coating layer (35) which is arranged on the second polyolefin layer (33) of the separation film (3), is positioned in the range of the second polyolefin layer (33), and correspondingly covers and exceeds the second active material layer (22);

wherein,

the first peripheral blank area (111) is bent and adhered with the first polyolefin layer (32) of the isolation film (3);

the second peripheral margin region (211) is folded and bonded to the second polyolefin layer (33) of the separator (3).

7. The flexible electrical core of claim 6,

the thickness of the first coating layer (34) is 3-20 μm;

the thickness of the second coating layer (35) is 3 μm to 20 μm.

8. The flexible electrical core of claim 6,

the first coating layer (34) is spaced from each edge of the first polyolefin layer (32) of the release film (3) by a distance d₁And d is₁≥3mm；

The second coating layer (35) is spaced from each edge of the second polyolefin layer (33) of the separator (3) by a distance d₂And d is₂≥3mm。

9. A method of making a flexible electrical core for use in making the flexible electrical core of any of claims 1-8, comprising the steps of:

a first active material layer (12) and a second active material layer (22) are intermittently provided at a first prescribed pitch b1 and a second prescribed pitch b2 on the facing surfaces of a first current collector (11) and a second current collector (21) of a first pole piece (1) and a second pole piece (2), respectively, the first current collector (11) has a first peripheral blank region (111) surrounding the first active material layer (12) without the first active material layer (12), the second current collector (21) has a second peripheral blank region (211) surrounding the second active material layer (22) without the second active material layer (22), the first pole piece (1) and the second pole piece (2) which are mutually overlapped are not provided with a first active material layer (12) and a second active material layer (22) on the surfaces, located on the outer sides, of the first current collector (11) and the second current collector (21) respectively;

drying and dewatering the first pole piece (1), the isolating film (3) provided with the insulating layer (31) and the first polyolefin layer (32) and the second polyolefin layer (33) which are adhered to the two opposite sides of the insulating layer (31), and the second pole piece (2);

spraying an electrolyte on the first active material layer (12) and/or the second active material layer (22);

mutually overlapping the first pole piece (1), the isolating film (3) and the second pole piece (2);

respectively carrying out hot pressing on a first peripheral blank area (111) on the surface of a first current collector (11) and a second peripheral blank area (211) on the surface of a second current collector (21) from the upper side and the lower side so as to enable the first peripheral blank area (111) to be bent and adhered with a first polyolefin layer (32) of the isolating membrane (3) and enable the second peripheral blank area (211) to be bent and adhered with a second polyolefin layer (33) of the isolating membrane (3) to manufacture a plurality of flexible battery cells; and

and (3) vertically shearing along the horizontal direction at the part where the first current collector (11) is adhered to the first polyolefin layer (32) of the isolating membrane (3) and at the part where the second current collector (21) is adhered to the second polyolefin layer (33) of the isolating membrane (3) correspondingly to form a single flexible battery core.

10. The method of making a flexible electrical core of claim 9,

the first polyolefin layer (32) of the separator (3) is provided with: a first coating layer (34) located within the first polyolefin layer (32) and correspondingly covering and extending beyond the first active material layer (12);

the second polyolefin layer (33) of the separator (3) is provided with: a second coating layer (35) located within the second polyolefin layer (33) and covering and exceeding the second active material layer (22) correspondingly;

after hot pressing, the first peripheral blank area (111) is bent and adhered to the first polyolefin layer (32) of the isolation film (3), and the second peripheral blank area (211) is bent and adhered to the second polyolefin layer (33) of the isolation film (3).