TWI900861B - A lithium ion battery cell - Google Patents

Abstract

The present invention relates to a lithium ion battery cell. The lithium ion battery cell includes at least a positive plate, at least a negative plate and a composite solid electrolyte film. The positive plate, the composite solid electrolyte film and the negative plate are sequentially stacked. Wherein the composite solid electrolyte film is a continuous membrane, and the composite solid electrolyte film includes a first composite solid electrolyte film and a second composite solid electrolyte film. The first composite solid electrolyte film is located between the positive plate and the negative positive plate, and the second composite solid electrolyte film is located on the side area of the lithium ion battery cell.

Description

Lithium-ion battery cells

The present invention relates to the field of lithium-ion battery technology, and in particular to a lithium-ion battery cell based on a solid electrolyte composite structure.

In the existing lithium-ion battery manufacturing process, the solid electrolyte is injected or coated in a fluid state onto the electrode surface. This requires flow control using a coating machine, making the manufacturing process complex and difficult to control.

Meanwhile, existing lithium-ion battery cells consist of a positive electrode, a negative electrode, and a separator. Existing technology often uses stacking equipment to alternately stack the pre-formed positive and negative electrodes with the separator in a fixed space. This process, without any surface bonding between the three, can easily cause wrinkles in the separator during stacking, leading to lithium deposition during charging and discharging, resulting in lithium dendrites and potentially causing safety accidents. Furthermore, the stacking process requires precise alignment of the positive and negative electrodes, as well as the separator, requiring high dimensional accuracy. Furthermore, the prepared lithium-ion battery cells are prone to interference with the aluminum foil packaging.

In view of this, it is necessary to provide a lithium-ion battery cell with a stable structure and high strength.

A lithium-ion battery cell includes at least one positive electrode and at least one negative electrode, the positive electrode and the negative electrode being spaced apart and stacked. At least one composite solid electrolyte membrane is disposed between the positive and negative electrodes. The composite solid electrolyte membrane is a continuous membrane structure comprising a first composite solid electrolyte membrane and a second composite solid electrolyte membrane. The first composite solid electrolyte membrane is located between the positive and negative electrodes and arranged parallel to the positive and negative electrodes. The second composite solid electrolyte membrane is located on a side surface of the lithium-ion battery cell.

Compared to prior art, the lithium-ion battery cell provided in this application includes a composite solid electrolyte membrane, with a portion of the composite solid electrolyte membrane structure disposed on the side of the lithium-ion battery cell. This structure facilitates the utilization of the internal battery space and enhances the side strength of the battery cell, preventing interference between the battery cell body and the battery packaging aluminum foil. This also improves the overall structural strength and stability of the battery cell, resulting in excellent cycling performance.

1: Positive electrode current collector

1”: Negative electrode fluid collector

10: Positive electrode

11: Cathode composite structure

12: Negative composite structure

2: Positive electrode material layer

2”: Negative material layer

20: Negative electrode

3: Composite solid electrolyte membrane

31: The first composite solid electrolyte membrane

32: Second composite solid electrolyte membrane

4: Battery cell prefabricated body

5: Transition layer

6: Battery cell molding device

61: Go to the platform

62: Get off the platform

63: Side trimming plate

64: Bottom folding plate

65: Sealing structure

7: Extreme Ears

100: Lithium-ion battery cell

Figure 1 is a schematic diagram of the relative positions of the cathode composite structure provided in one embodiment of this application.

Figure 2 is a schematic diagram showing the transition dimensions of the cathode composite structure provided in one embodiment of this application.

Figure 3 is a schematic diagram of the right side (non-ear side) of a battery cell preform formed by stacking the first composite structure and the second composite structure provided in an embodiment of the present application.

Figure 4 is a schematic diagram showing the front side (ear side) of a battery cell preform formed by stacking the first composite structure and the second composite structure provided in an embodiment of the present application.

Figure 5 is a flowchart of the preparation process for pressing, trimming, and fixing a battery cell preform (non-ear side) according to an embodiment of this application.

Figure 6 is a flowchart of the preparation process for pressing, trimming, and fixing a battery cell preform (on the lug side) according to an embodiment of this application.

Figure 7 is a schematic diagram of the completed lithium-ion battery cell provided in one embodiment of this application.

Figure 8 is a schematic cross-sectional view of a lithium-ion battery cell provided in accordance with an embodiment of this application.

Figure 9 is a schematic diagram of a completed lithium-ion battery cell comprising multiple positive electrode composite structures and multiple negative electrode composite structures provided in accordance with an embodiment of the present application.

Figure 10 is a schematic cross-sectional view of a lithium-ion battery cell comprising multiple positive electrode composite structures and multiple negative electrode composite structures, provided in accordance with one embodiment of the present application.

The following is a detailed description of the method for preparing a lithium-ion battery cell according to an embodiment of the present invention with reference to the accompanying figures.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the embodiments of this application pertain. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of this application.

Furthermore, terms such as "first," "second," and so on, used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referenced. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise explicitly and specifically specified.

The following, combined with the accompanying figures, provides a detailed description of some embodiments of this application. The following embodiments and features thereof may be combined with each other unless there is any conflict.

The first embodiment of the present application provides a method for preparing a lithium-ion battery cell, comprising the following steps: S1, providing a positive electrode sheet 10, and disposing a composite solid electrolyte membrane 3 on two opposing surfaces of the positive electrode sheet 10 to form a positive electrode composite structure 11; S2, providing a negative electrode sheet 20, and disposing the composite solid electrolyte membrane 3 on two opposing surfaces of the negative electrode sheet 20. The solid electrolyte membrane 3 is combined to form a negative electrode composite structure 12; S3, at least one positive electrode composite structure 11 and at least one negative electrode composite structure 12 are stacked to form a battery cell preform 4; S4, the battery cell preform 4 is pressed, and the composite solid electrolyte membrane 3 in the battery cell preform 4 is trimmed, shaped, and fixed to obtain the lithium-ion battery cell.

In step S1, the positive electrode sheet 10 includes a positive electrode current collector 1 and positive electrode material layers 2 disposed on two opposing surfaces of the positive electrode current collector, as shown in Figure 1. The positive electrode current collector 1 is a metal foil, such as an aluminum sheet or a copper sheet. The positive electrode material layer 2 includes a positive electrode material, which can be a commonly used positive electrode material. The positive electrode material can be at least one of a layered lithium-transition metal oxide, a spinel lithium-transition metal oxide, and an olivine lithium-transition metal oxide, such as olivine lithium iron phosphate, layered lithium cobalt oxide, layered lithium manganate, spinel lithium manganate, lithium nickel manganate oxide, and lithium nickel cobalt manganese oxide. The positive electrode material layer 2 can further include a conductor and a binder, both of which can be conventionally used in the prior art. The positive electrode material layer is formed by coating the positive electrode current collector with a slurry.

The composite solid electrolyte membrane 3 is laminated and disposed on the surface of the positive electrode material layer 2, distal from the positive electrode current collector 1, by heat pressing, thereby obtaining the positive electrode composite structure 11. The composite solid electrolyte membrane 3 is a formed layered structure, meaning that it is already an independent layered structure before being formed on the positive electrode material layer 2. The composite solid electrolyte membrane 3 can be directly laid flat on the surface of the positive electrode material layer 2, distal from the positive electrode current collector 1, rather than being formed by applying a coating of the composite solid electrolyte membrane 3 on the surface of the positive electrode material layer 2 and then drying it.

The composite solid electrolyte membrane 3 includes a polymer material and an inorganic solid electrolyte. Furthermore, the composite solid electrolyte membrane 3 can be a composite membrane composed of a polymer material and an inorganic solid electrolyte. The polymer material can be polyvinylidene fluoride, polymethyl methacrylate, polyethylene oxide, etc. The polymer material can soften due to heat, forming a localized softening on the surface, and has surface micro-adhesion and thermoplasticity. Therefore, the polymer material can also improve the ductility and toughness of the composite solid electrolyte membrane 3. The inorganic solid electrolyte can be lithium chromium zirconium oxide, lithium aluminum titanium phosphate, lithium chromium titanium oxide, etc. The inorganic solid electrolyte can improve ionic conductivity, prevent lithium dendrite penetration, and at the same time improve the mechanical strength of the composite solid electrolyte membrane 3. After heating, the composite solid electrolyte membrane 3 develops a slightly plastic and slightly sticky surface. During continued pressing, the composite solid electrolyte membrane 3 and the cathode material layer 2 achieve a transitional bond, achieving optimal adhesion without damaging the surface morphology of the cathode material layer 2 and maintaining its material properties. Furthermore, the composite solid electrolyte membrane 3 solidifies after cooling, facilitating subsequent manufacturing processes. Preferably, the thickness of the composite solid electrolyte membrane 3 is between 5 and 100 microns.

As shown in Figure 2, during the hot pressing process, a transition layer 5 is formed between the composite solid electrolyte membrane 3 and the cathode material layer 2. The transition layer 5 is formed by the interlocking uneven surface structure formed by the contact portions of the composite solid electrolyte membrane 3 and the cathode material layer 2 after the composite solid electrolyte membrane 3 is heated. This interlocking region is the transition layer 5.

During the hot pressing process of the composite solid electrolyte membrane 3 and the positive electrode material layer 2, the thickness of the transition layer 5 is 0.1 micron to 5.0 microns to ensure good bonding between the composite solid electrolyte membrane 3 and the adjacent positive electrode material layer 2. If the thickness of the transition layer 5 is less than 0.1 micron, the transition layer 5 is too thin. During the subsequent hot pressing process of the battery cell preform 4, the composite solid electrolyte membrane 3 and the adjacent positive electrode sheet 10 or negative electrode sheet 20 cannot achieve good bonding, resulting in peeling due to poor bonding. If the thickness of the transition layer 5 is greater than 5.0 microns, the thickness of the transition layer 5 effectively compresses the insulation protection function, easily causing internal short circuits between the positive and negative electrodes, thus affecting battery safety. Specifically, the heat pressing process can be performed using a flat press. In this embodiment, the heat pressing temperature is 50°C to 250°C, the pressing speed is 0.1 μm/second, the fixed force is 0.01 kg/ ^cm² to 20.0 kg/ ^cm² , and the travel time of a single press is controlled within 10 seconds. It can be understood that the thickness of the positive electrode composite structure 11 formed by the positive electrode sheet 10 and the composite solid electrolyte membrane 3 can be obtained by controlling the hot pressing temperature, constant pressure and pressing time.

In this embodiment, the thickness of the transition layer 5 is 0.1 microns to 5.0 microns. This thickness range ensures that the electrode sheet adjacent to the composite solid electrolyte membrane 3 has a good surface morphology while also ensuring good adhesion between the composite solid electrolyte membrane and the adjacent electrode sheet, thereby ensuring that the resulting electrode sheet and the composite solid electrolyte membrane have good cycling performance.

In step S2, the negative electrode sheet 20 includes a negative electrode current collector 1' and negative electrode material layers 2' disposed on two opposing surfaces of the negative electrode current collector 1'. The negative electrode material layer 2' includes a negative electrode material, which is a commonly used negative electrode material. The negative electrode material can be a carbon material, such as graphite, or a non-carbon material, such as a silicon-carbon composite. The negative electrode material layer 2' may further include a conductive agent and a binder (not shown). Both the conductive agent and the binder can be conventionally used in the prior art.

The composite solid electrolyte membrane 3 is placed on the surface of the negative electrode sheet 20 to prepare the negative electrode composite structure 12. Specifically, the composite solid electrolyte membrane 3 is laminated and placed on the surface of the negative electrode material layer away from the negative electrode current collector by hot pressing. The preparation method of the negative electrode composite structure 12 is basically the same as that of the positive electrode composite structure 11, except that the positive electrode sheet 10 is replaced by the negative electrode sheet 20. The details will not be repeated here.

In step S3, at least one positive electrode composite structure 11 and at least one negative electrode composite structure 12 are stacked to form a battery cell preform 4. Please refer to Figures 3 and 4 for schematic structural diagrams of the battery cell preform 4 from the right and front sides. The number of positive electrode composite structures 11 and negative electrode composite structures 12 included in the battery cell preform 4 can be selected based on actual needs. The composite solid electrolyte membrane 3 serves to insulate and separate the positive electrode sheet 10 from the negative electrode sheet 20. The area of the composite solid electrolyte membrane 3 is larger than that of the positive electrode 10 or the negative electrode 20. That is, the composite solid electrolyte membrane 3 can completely cover the positive electrode 10 or the negative electrode 20. This ensures that if the positive electrode 10 or the negative electrode 20 shifts, the composite solid electrolyte membrane 3 can still isolate the positive electrode 10 and the negative electrode 20. Furthermore, because the area of the composite solid electrolyte membrane 3 is larger than that of the positive electrode 10 or the negative electrode 20, the composite solid electrolyte membrane 3 does not need to be aligned with the positive electrode 10 or the negative electrode 20.

As long as the positive electrode sheet 10 and the negative electrode sheet 20 in the battery cell preform 4 are insulated, at least one composite solid electrolyte membrane 3 is present between the positive electrode sheet 10 and the negative electrode sheet 20. That is, when at least the positive electrode composite structure 11 and at least one negative electrode composite structure 12 are stacked, one of the two composite solid electrolyte membranes in the positive electrode composite structure 11 or the negative electrode composite structure 12 can be removed, leaving only one composite solid electrolyte membrane between the positive electrode sheet 10 and the negative electrode sheet 20.

Therefore, it is understood that, before step S3, the preparation method may include a step of removing the composite solid electrolyte membrane 3 from the positive electrode composite structure 11 or the negative electrode composite structure 12. The location of the composite solid electrolyte membrane 3 to be removed can be selected based on actual needs, as long as insulation is ensured between the positive electrode sheet 10 and the negative electrode sheet 20 in the battery cell preform 4.

In one embodiment, the battery cell preform 4 is composed of a stack of the positive electrode composite structure 11 and the negative electrode composite structure 12.

In another embodiment, the battery cell preform 4 includes a plurality of the positive electrode composite structures 11 and a plurality of the negative electrode composite structures 12, and the plurality of the positive electrode composite structures 11 and the plurality of the negative electrode composite structures 12 are alternately stacked.

During the pressing process of the battery cell preform 4 in step S4, the battery cell preform 4 is placed horizontally and vertical pressure is applied to the battery cell preform 4. The applied pressure is perpendicular to the surface of the battery cell preform 4, ensuring that the upper and lower surfaces of the battery cell preform 4 remain flat during the pressing process. Because the area of the composite solid electrolyte membrane 3 in the battery cell preform 4 is different from that of the positive electrode sheet 10 or the negative electrode sheet 20, the composite solid electrolyte membrane 3 protrudes from the positive electrode sheet 10 or the negative electrode sheet 20, resulting in uneven side edges of the battery cell preform 4 after pressing. Trimming and fixing the battery cell preform 4 involves folding the uneven side edges of the battery cell preform 4 in a uniform direction to maintain the side edges. The folded side edges are then fixed, resulting in a battery cell with neat side edges and a stable structure. Here, the uneven side edges of the battery cell preform 4 refer to the composite solid electrolyte membrane 3 protruding from the positive electrode 10 or negative electrode 20.

The processes of pressing, trimming, shaping, and fixing the cell preform 4 are all accomplished by a cell forming device 6. The cell forming device 6 comprises an upper platform 61, a lower platform 62, a side trimming press plate 63, and a lower folding plate 64. The upper platform 61 and the lower platform 62 are spaced apart and used to apply pressure to the cell preform 4 for compression. The side trimming press plate 63 and the lower folding plate 64 are used to trim and shape the side edges of the cell preform 4. After trimming and shaping the battery cell preform 4, the battery cell forming device 6 can further glue and secure the battery cell preform 4, thereby ensuring that the structure after the folded side edges remains stable and does not deform. The specific steps of using the battery cell forming device 6 to press, trim, and secure the battery cell preform 4 are as follows:

S41: Position, place, and clamp the preform 4. Referring to Figure 5 , the preform 4 is placed horizontally on the lower platform 62 of the cell forming apparatus 6 . The upper platform 61 is lowered to clamp and secure the preform 4 . To ensure the flatness of the preform 4 , the pressure is controlled within 5000 kg/ ^cm² . This pressure range secures the preform 4 in place while also flattening it.

In step S42, the side-collapsing press plate 63 moves vertically downward, folding the side edge structure of the cell preform 4 downward. The lower folding plate 64 rotates upward, folding the side edge structure upward until it is again attached to the side edge of the cell preform 4. As shown in Figure 5, the side-collapsing press plate 63 moves vertically downward from above the cell preform 4, collecting the composite solid electrolyte membrane 3 protruding from the positive electrode 10 or negative electrode 20. Due to the tapered design of the side-collapsing press plate 63, the collection process does not damage the composite solid electrolyte membrane 3. Furthermore, the surface of the side-edge-collecting plate 63 has an anti-static component that prevents adhesion to the surface of the polymer composite solid electrolyte membrane. The lower folding plate 64 rotates upward around the lower edge of the cell preform 4 until it is perpendicular to the horizontal direction of the cell preform 4, whereupon it stops. At this point, the side edge portion collected by the side-edge-collecting plate 63 is folded over and adhered to the side edge of the cell preform 4. The upward folding of the composite solid electrolyte membrane 3 by the lower folding plate 64 can confine the composite solid electrolyte membrane 3 to the side area of the battery cell preform 4, thereby preventing the composite solid electrolyte membrane 3 from interfering with the upper and lower surfaces of the battery cell preform 4.

Furthermore, please refer to Figures 6 and 7. When the battery cell preform 4 is provided with a tab 7, since the tab 7 is also located in the side area of the battery cell preform 4, the thickness difference of the tab must be considered during the folding process. The size of the folding plate should be designed based on the location of the tab to ensure the safety and aesthetic requirements of the subsequent battery packaging.

The side edge-trimming pressure plates and lower folding plates of the present invention can be customized to the size and shape of the battery. Their purpose is to trim the edges of the protruding composite solid electrolyte membrane 3, thereby minimizing internal battery space and increasing volumetric energy density. This embodiment is illustrated using a square battery, but its application is not limited to square batteries.

S43: Glue the battery cell preform 4. The battery cell forming device 6 may further include a glue supply wheel and a glue clamp (not shown). When the battery cell forming device 6 performs the sealing and attaching process, the glue supply wheel is used to feed glue and automatically cut it to a specified length. The glue clamp then grasps the glue and positions the sealing structure 65 in the lower slot of the battery cell preform 4. After gluing the lower portion, the glue clamp continues to move upward to a fixed length position, then presses down to complete the gluing process. This process completes one gluing point, and the remaining gluing points are repeated in this cycle until all gluing points are completed.

This application provides a method for preparing a lithium-ion battery cell. The composite solid electrolyte membrane can be directly laminated and pressed onto the positive and negative electrodes to form a lithium-ion battery cell. Precise alignment of the composite solid electrolyte membrane with the positive and negative electrodes is not required prior to pressing, and large dimensional errors can be tolerated. The preparation process is simple, easy to control, and suitable for industrial production.

Please refer to FIG. 7 and FIG. 8 together. The second embodiment of the present application provides a lithium-ion battery cell 100. The lithium-ion battery cell 100 includes the positive electrode composite structure 11 and the negative electrode composite structure 12 in the above-mentioned embodiments. The positive electrode composite structure 11 and the negative electrode composite structure 12 are stacked. The positive electrode composite structure 11 includes a positive electrode sheet 10 and a composite solid electrolyte membrane 3 provided on two opposite surfaces of the positive electrode sheet 10. The negative electrode composite structure 12 includes a negative electrode sheet 20 and composite solid electrolyte membranes 3 disposed on two opposing surfaces of the negative electrode sheet 20. The composite solid electrolyte membrane 3 is a continuous membrane structure and is divided into two parts. The first composite solid electrolyte membrane 31 is located between the positive electrode sheet 10 and the negative electrode sheet 20 and is arranged parallel to the positive electrode sheet 10 and the negative electrode sheet 20. The second composite solid electrolyte membrane 32 is folded on the side area of the lithium-ion battery cell 100.

The structure and arrangement of the positive electrode composite structure 11 and the negative electrode composite structure 12 are identical to those of the first embodiment. The positive electrode composite structure 11 includes a positive electrode sheet 10 and a composite solid electrolyte membrane 3" disposed on two opposing surfaces of the positive electrode sheet. The negative electrode composite structure 12 includes a negative electrode sheet 20 and a composite solid electrolyte membrane 3" disposed on two opposing surfaces of the negative electrode sheet 20. The structures of the positive electrode sheet 10 and the negative electrode sheet 20 are identical to those of the first embodiment and will not be further described here.

Further, referring to FIG9 and FIG10, the lithium-ion battery cell 100 includes a plurality of positive electrode composite structures 11 and a plurality of negative electrode composite structures 12, wherein the plurality of positive electrode composite structures 11 and the plurality of negative electrode composite structures 12 are stacked in layers. Specifically, the lithium-ion battery cell 100 includes N positive electrode composite structures 11 and N negative electrode composite structures 12, wherein N 2, N can be 2, 3, 4, 5, 6, etc. It can be understood that the value of N is a positive integer and has no upper limit, and the value of N can be set according to the structural size of the lithium-ion battery cell 100.

The composite solid electrolyte membrane 3 is provided on both surfaces of the positive electrode sheet 10 and the negative electrode sheet 20. The area of each composite solid electrolyte membrane 3 is larger than that of the positive electrode sheet 10 or the negative electrode sheet 20. In other words, the composite solid electrolyte membrane 3 can completely cover the positive electrode sheet 10 or the negative electrode sheet 20, thereby isolating the positive electrode sheet 10 and the negative electrode sheet 20. Therefore, when the composite solid electrolyte membrane 3 is laminated with the positive electrode sheet 10 and the negative electrode sheet 20, the portion where the composite solid electrolyte membrane 3 overlaps with the positive electrode sheet 10 or the negative electrode sheet 20 is the first composite solid electrolyte membrane 31. The first composite solid electrolyte membrane 31 is laminated with the positive electrode sheet 10 and the negative electrode sheet 20 and is parallel to each other. The portion of the composite solid electrolyte membrane 3 that protrudes from the positive electrode 10 or negative electrode 20 is the second composite solid electrolyte membrane 32. This second composite solid electrolyte membrane 32 extends to the side of the lithium-ion battery cell 100. By folding the second composite solid electrolyte membrane 32 in a uniform direction on the side of the lithium-ion battery cell 100, the overall structure of the lithium-ion battery cell 100 is more neat, facilitating subsequent handling.

As shown above, placing the second composite solid electrolyte membrane 32 on the side of the lithium-ion battery cell 100 facilitates the utilization of the battery's internal space while preventing interference with the upper and lower surfaces of the battery cell, thereby improving the overall structure of the battery cell. Furthermore, the two-part arrangement of the composite solid electrolyte membrane 3 enhances the side strength of the battery cell, preventing interference between the battery cell body and the battery packaging aluminum foil, and improving the overall structural strength and stability of the battery cell.

Referring to Figures 7 and 9 , the lithium-ion battery cell 100 further includes a sealing structure 65 comprising at least one adhesive tape. Each adhesive tape extends from the bottom to the top of the lithium-ion battery cell 100, securing the second composite solid electrolyte membrane 32 folded over the side. When the sealing structure 65 includes multiple adhesive tapes, the tapes are spaced apart on the lithium-ion battery cell 100. Specifically, the tapes are distributed around the lithium-ion battery cell 100 and extend from the bottom to the top, providing support points for the second composite solid electrolyte membrane folded over the side.

The lithium-ion battery cell provided in this application includes a composite solid electrolyte membrane, with a portion of the composite solid electrolyte membrane structure disposed on the side area of the lithium-ion battery cell. This structure facilitates the utilization of the internal space of the battery while enhancing the side strength of the battery cell. This prevents interference between the battery cell body and the battery packaging aluminum foil, improves the overall structural strength and stability of the battery cell, and ensures that the lithium-ion battery cell has good cycling performance.

In summary, this invention meets the requirements for a patent, and a patent application has been filed in accordance with the law. However, the above examples are merely preferred embodiments of this invention and should not limit the scope of the patent application. Any equivalent modifications or variations made by persons skilled in the art based on the spirit of this invention should be covered by the scope of the patent application below.

10: Positive electrode 11: Positive electrode composite structure 12: Negative electrode composite structure 20: Negative electrode 3: Composite solid electrolyte membrane 31: First composite solid electrolyte membrane 32: Second composite solid electrolyte membrane 65: Sealing structure 100: Lithium-ion battery cell

Claims (8)

A lithium-ion battery cell comprises at least one positive electrode and at least one negative electrode, the positive electrode and the negative electrode being spaced apart and stacked, and at least one composite solid electrolyte membrane being disposed between the positive electrode and the negative electrode. The battery cell is characterized by: The composite solid electrolyte membrane comprises a polymer material and an inorganic solid electrolyte. The composite solid electrolyte membrane is a continuous membrane structure comprising a first composite solid electrolyte membrane and a second composite solid electrolyte membrane. The first composite solid electrolyte membrane is located between the positive electrode sheet and the negative electrode sheet and is arranged parallel to the positive electrode sheet and the negative electrode sheet. The second composite solid electrolyte membrane protrudes from the positive electrode sheet or the negative electrode sheet, extends to the side area of the lithium-ion battery cell, and is adhered to the side area of the lithium-ion battery cell. The composite solid electrolyte membrane completely covers the positive electrode sheet or the negative electrode sheet. The lithium-ion battery cell of claim 1, wherein the positive electrode sheet includes a positive electrode collector and a positive electrode material layer disposed on the positive electrode collector, and the first composite solid electrolyte membrane is disposed on a surface of the positive electrode material layer away from the positive electrode collector. The lithium-ion battery cell of claim 2 further includes a transition layer between the first composite solid electrolyte membrane and the positive electrode material layer, wherein the transition layer is an interlaced interval structure formed by the contact portions of the first composite solid electrolyte membrane and the positive electrode material layer being interlocked with each other. In the lithium-ion battery cell of claim 3, the thickness of the transition layer is in the range of 0.1 μm to 5.0 μm. The lithium-ion battery cell of claim 1, wherein the polymer material is one or more of polyvinylidene fluoride, polymethyl methacrylate, and polyethylene oxide. The lithium-ion battery cell of claim 1, wherein the inorganic solid electrolyte is one or more of lithium vanadium zirconium oxide, lithium aluminum titanium phosphate, and lithium vanadium titanium oxide. The lithium-ion battery cell of claim 1, comprising a sealing structure including at least one adhesive tape, wherein the lithium-ion battery cell includes an upper plane and a lower plane opposite to the upper plane, and the adhesive tape extends from the lower plane to the upper plane of the lithium-ion battery cell. The lithium-ion battery cell of claim 7, wherein the sealing structure includes a plurality of adhesive tapes, the plurality of adhesive tapes are distributed around the lithium-ion battery cell, and each adhesive tape extends from the lower plane to the upper plane of the lithium-ion battery cell.