Battery cells and their manufacturing methods and batteries

Abstract

The present invention discloses a battery cell and a preparation method thereof and a battery. The battery cell of the present invention includes a diaphragm, and also includes: a first electrode sheet, including a plurality of U-shaped or V-shaped folding structure units; a second electrode sheet, including a folding fan structure formed by folding a whole electrode sheet, the folding fan structure having a plurality of folding portions and a plurality of bending portions connecting two adjacent folding portions, at least two folding surfaces opposite to the folding portions are bonded with a diaphragm, the folding structure units are inserted into the folding gap of the folding fan structure at intervals and bonded to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence to form a battery cell unit, and the battery cell of the present invention includes at least one battery cell unit. The battery contains the battery cell of the present invention. The battery cell is provided with the first electrode sheet and the second electrode sheet structure, so that the two electrode sheets form an intercalation battery cell structure to play a synergistic role, effectively reduce the ohmic resistance of the intercalation battery cell, give the battery cell high safety performance, and make the battery cell suitable for large-capacity batteries.

Description

Technical Field

[0001] The invention belongs to the field of batteries, and in particular relates to a battery cell and a preparation method thereof, and a battery. Background Art

[0002] As an energy storage device, the battery mainly consists of the following parts: positive electrode, negative electrode, separator, and electrolyte. Among them, the positive electrode, separator, and negative electrode are stacked in sequence to form a sandwich structure to form a battery cell. In addition to the materials and properties of the positive electrode, negative electrode, separator, and electrolyte, which play a vital role in the electrochemical performance and safety of the battery cycle, the structure of the battery cell itself also plays a vital role in the electrochemical performance and safety.

[0003] Conventional batteries such as secondary batteries generally contain cells of laminated structure. For example, before assembling lithium-sulfur batteries, the positive and negative electrode sheets must be cut into the required shape, and then the positive / diaphragm / negative electrode sheets are laminated to form a cell. In this way, the current collectors of each positive electrode sheet and each negative electrode sheet are only connected by welding at the tabs, resulting in a large ohmic resistance of the entire positive electrode system or negative electrode system. During the battery charging and discharging process, the tab connection is prone to heat and temperature rise, which affects the battery performance and poses a safety hazard. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a battery cell and a method for preparing the same, so as to solve the technical problem that the existing laminated battery cells are connected by welding the tabs, resulting in high resistance and safety hazards.

[0005] Another object of the present invention is to provide a battery to solve the technical problem that the existing battery has unsatisfactory electrochemical performance and safety due to the existing laminated battery core contained therein.

[0006] In order to achieve the above-mentioned object of the invention, one aspect of the present invention provides a battery cell. The battery cell of the present invention comprises a separator and further comprises:

[0007] The first electrode sheet includes a plurality of U-shaped or V-shaped folding structure units;

[0008] The second electrode sheet comprises a folding fan-shaped structure formed by folding a whole electrode sheet, the folding fan-shaped structure has a plurality of folding portions and a plurality of bending portions connecting two adjacent folding portions, at least two folding portions opposite to the folding portions are attached with a diaphragm, and the folding structure units are inserted into the folding gaps of the folding fan-shaped structure at intervals and attached to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence;

[0009] The battery cell comprises at least one battery cell unit which is formed by sequentially stacking a first electrode sheet, a separator and a second electrode sheet.

[0010] Another aspect of the present invention provides a method for preparing the battery cell of the present invention. The battery cell of the present invention comprises the following steps:

[0011] Obtaining a first electrode sheet body, the first electrode sheet body comprising a plurality of electrode sheet sections, folding each electrode sheet section into a U-shape or a V-shape to form a plurality of U-shaped or V-shaped folding structure units to form a first electrode sheet;

[0012] Obtaining a second electrode sheet body, and folding the second electrode sheet body in a fan-shaped manner to form a fan-shaped structure; and making the fan-shaped structure have a plurality of folding portions and a plurality of bending portions connecting two adjacent folding portions to form a second electrode sheet;

[0013] The diaphragm is attached to at least two opposite folded surfaces of the folded surface;

[0014] Insert the folding structure units into the fold gaps of the folding fan structure at intervals and attach them to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence to form a battery cell unit;

[0015] Assemble at least one battery cell unit into a battery cell.

[0016] In another aspect of the present invention, a battery is provided. The battery of the present invention comprises a battery cell, which is the battery cell of the present invention or a battery cell prepared by the method for preparing the battery cell of the present invention.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] The battery cell of the present invention sets one of the electrode sheets contained in the battery cell unit of the battery cell, namely the second electrode sheet, into a folding fan structure, retaining the integration of the second electrode sheet, so that the second electrode sheet is directly connected as a whole through the contained current collector, thereby greatly reducing the ohmic resistance of the second electrode sheet and also improving the safety performance. The contained first electrode sheet is set as a plurality of folding structure units, and forms an intercalation battery cell unit structure with the second electrode sheet, thereby effectively reducing the ohmic resistance of the second electrode sheet. In this way, by setting the first electrode sheet and the second electrode sheet structure, the two pole sheets form an intercalation battery cell structure to play a synergistic role to effectively reduce the ohmic resistance of the intercalation battery, giving the battery cell of the present invention high safety performance, effectively overcoming the high resistance defect of the existing laminated battery cell, making the battery cell of the present invention suitable for large-capacity batteries.

[0019] The battery cell preparation method of the present invention directly sets the first electrode sheet body into a plurality of folding structure units according to the battery cell structure of the present invention, folds the second electrode sheet body in a fan-shaped manner, and assembles the two according to the intercalation battery cell structure of the battery cell of the present invention to form a battery cell unit, thereby giving the prepared battery cell the characteristics of low ohmic resistance and high safety. In addition, the battery cell preparation method of the present invention has an easy-to-control process, and the quality and performance of the prepared battery cell are stable and the efficiency is high.

[0020] The battery cell of the present invention is the battery cell of the present invention. Therefore, the battery of the present invention has a small internal resistance, excellent rate performance, high safety, and can also be a large-capacity battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the structure of the battery cell unit contained in the battery cell of an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the structure of the first electrode sheet body and the U-shaped or V-shaped folding structure unit formed by U-shaped or V-shaped folding; wherein, Figure a is a schematic diagram of the structure of the first electrode sheet body before the U-shaped or V-shaped folding process, and Figure b is a schematic diagram of the structure of the folding structure unit;

[0024] Figure 3 Schematic diagram of the second electrode sheet body and the fan-shaped structure formed by the fan-shaped folding process; wherein, FIG. c is a schematic diagram of the structure of the second electrode sheet body before the fan-shaped folding process, and FIG. d is a schematic diagram of the fan-shaped structure;

[0025] Figure 4 The schematic diagram of the structure of the battery of the embodiment of the present invention is a lithium-sulfur soft-pack battery.

[0026] Description of the component numbers in the accompanying drawings:

[0027] 01-a section of the first electrode sheet body; 1-the first electrode sheet; 1'-a folding structure unit; 11-a folding portion of the folding structure unit; 12-a bending portion of the folding structure unit; 13-a pole ear of the first electrode sheet 1; 14-a bending line of the electrode sheet 01 for U-shaped or V-shaped folding;

[0028] 02-second electrode sheet body; 2-second electrode sheet; 21-folding portion of the folding fan structure; 21a-one folding portion of the folding fan structure; 21b-the other folding portion of the folding fan structure;

[0029] 22-a bending portion of the fan-shaped structure; 22a-a bending portion of the fan-shaped structure connected to the folding surface portion 21a; 22b-a bending portion of the fan-shaped structure connected to the folding surface portion 21b; 23-a pole ear of the second electrode sheet 2; 24-a bending line of the second electrode sheet body for fan-shaped folding;

[0030] 23-a folding gap of the fan-shaped structure; 23a-a folding gap of the fan-shaped structure; 23b-a folding gap of the fan-shaped structure adjacent to the folding gap 23a; 23c-another folding gap of the fan-shaped structure; 23d-a folding gap of the fan-shaped structure adjacent to the folding gap 23c;

[0031] 3- Diaphragm. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and technical effect of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is clearly and completely described. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. In conjunction with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer; if the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0033] In the description of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0034] In the description of the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0035] In addition, unless the context clearly uses otherwise, the expression of the singular form of a word should be understood to include the plural form of the word. The term "includes" or "having" is intended to specify the existence of a feature, quantity, step, operation, element, part or combination thereof, but is not used to exclude the existence or possible addition of one or more other features, quantities, steps, operations, elements, parts or combinations thereof.

[0036] Explanation of the relevant names below:

[0037] Battery cell: refers to Figures 1 to 3 The first electrode sheet 1, the second electrode sheet 2 and the diaphragm 3 are stacked in a stacking manner of first electrode sheet 1 / diaphragm 3 / second electrode sheet 2 to form a combined structure.

[0038] U-shaped or V-shaped folding structure: refers to Figure 2 A section of the electrode sheet shown in Figure a is folded into a U-shape or a V-shape to form Figure 2 The U-shaped or V-shaped structure shown in Figure b.

[0039] Folding fan structure: refers to Figure 3 The electrode sheet 2' shown in Figure c is folded into a fan-shaped pattern. Figure 3 The structure shown in Figure d.

[0040] Folding surface: refers to the area of ​​the conventional folding fan structure containing the folding surface, such as Figure 3 The electrode sheet area is shown in Figure 21.

[0041] Bending section: refers to the bending area connecting two adjacent folding sections in a conventional folding fan structure. Figure 3 The electrode sheet area is shown in Figure 22.

[0042] In one aspect, an embodiment of the present invention provides a battery cell. The battery cell of the embodiment of the present invention includes at least one battery cell unit, wherein the structure of the battery cell unit is as follows: Figures 1 to 3 As shown, it includes components such as a first electrode sheet 1, a second electrode sheet 2 and a diaphragm 3, that is, the first electrode sheet 1, the diaphragm 3 and the second electrode sheet 2 are stacked in sequence to form a battery cell unit.

[0043] The structure of the first electrode sheet 1 is as follows Figure 1 and Figure 2 As shown, it includes a plurality of U-shaped or V-shaped folding structure units 1'. The structure of the U-shaped or V-shaped folding structure unit 1' is as follows Figure 1 and Figure 2As shown in FIG. b, it includes folding portions 11 at both ends and a U-shaped or V-shaped bending portion 12 connecting the two folding portions 11. The folding portion 11 includes two folding pages arranged opposite to each other, and the bending portion 12 includes a convex surface and a concave surface arranged opposite to each other. The first electrode sheet 1 is arranged as a plurality of folding structure units 1', which is equivalent to directly forming the two electrodes contained in the traditional disc-type battery cell into a whole, which effectively reduces the ohmic resistance of the first electrode sheet.

[0044] In the embodiment of the present invention, the gap between the bending portion 12 and the two folding portions 11 needs to be covered by Figure 1 and Figure 3 The bending portion 22 of the second electrode sheet 2, therefore, in order to make the bending portion 12 better arranged on the convex bending surface side of the bending portion 22 of the second electrode sheet 2, the U-shaped morphology is preferred relative to the V-shaped morphology.

[0045] In addition, the number of "several" in the several folding structure units 1' in the embodiment of the present invention should refer to at least two or more, which is specifically determined according to the number of the folding portions 22 of the second electrode sheet 2. The area of ​​the folding portion 11 can also be controlled and selected according to the needs of specific applications, and is ideally equivalent to the area of ​​the folding portion 21 of the second electrode sheet 2.

[0046] The structure of the second electrode sheet 2 is as follows Figure 1 and Figure 3 As shown, a fan-shaped structure is formed by folding a whole electrode sheet, and the fan-shaped structure has a plurality of folding portions 21 and a plurality of bending portions 22 connecting two adjacent folding portions 21. The second electrode sheet 2 is a fan-shaped structure, which retains the integration of the second electrode sheet 2, so that the second electrode sheet 2 is directly connected as a whole through the current collector contained therein, thereby greatly reducing the ohmic resistance of the second electrode sheet 2 and improving the safety performance.

[0047] Of course, the bending portion 22 of the folding fan structure 2 can be a U-shape or a V-shape, which are typical but non-limiting shapes.

[0048] In the embodiment, the number of the folded portions 21 included in the second electrode sheet 2 is at least two, which can be flexibly controlled as needed. Moreover, by controlling the number of the folded portions 21, the thickness of the cell unit and the chemical properties such as the cell capacity can be adjusted, thereby achieving the adjustment of the thickness of the cell unit and the chemical properties such as the cell capacity.

[0049] In addition, the number of "several" in the several folding portions 21 and the several bending portions 22 in the embodiment of the present invention should refer to at least two or more, which can be flexibly selected and controlled according to the capacity or thickness requirements of the battery cell and the battery cell unit. The area size of the folding portion 21 can also be controlled and selected according to the needs of the specific application.

[0050] Based on the structure of the first electrode sheet 1 and the second electrode sheet 2, the diaphragm 3 contained in the battery cell unit of the embodiment of the present invention is at least attached to the two folded surfaces opposite to the folded surface 21, and the folded structure unit 1' is inserted into the folded gap 23 of the folded fan structure of the second electrode sheet 2 (the folded gap 23 is formed by the adjacent folded surface 21) at intervals and attached to the outer surface of the diaphragm 3. Through the bonding method of the first electrode sheet 1 and the second electrode sheet 2, the first electrode sheet 1, the diaphragm 3 and the second electrode sheet 2 are stacked in sequence. In this way, the embodiment of the present invention, through the arrangement of the structure of the first electrode sheet 1 and the second electrode sheet 2, makes the two poles constitute the intercalation battery cell unit structure to play a synergistic role, effectively reduces the ohmic resistance of the intercalation battery cell unit, thereby giving the battery cell high safety performance, effectively overcoming the high resistance defect of the existing laminated battery cell, making the battery cell of the embodiment of the present invention suitable for large-capacity batteries and improving the safety performance of large-capacity batteries.

[0051] In the embodiment, the intercalation cell unit structure constructed by the first electrode sheet 1 and the second electrode sheet 2 is as follows: Figure 1 As shown, one end of one of the folding structure units 1' of the first electrode sheet 1, that is, one of the folding portions 11, is inserted into a folding gap 23 of the folding fan-shaped structure and adheres to the outer surface of the diaphragm 3 in the folding gap 23. The diaphragm 3 is at least adhered to the folding surface of the folding surface portion 21 in the folding gap 23; the other end of the folding structure unit 1', that is, another folding portion 11 of the folding structure unit 1', is inserted into another folding gap 23 adjacent to the folding gap 23 of the folding fan-shaped structure and adheres to the outer surface of the diaphragm 3. At this time, the diaphragm 3 is also at least adhered to the folding surface of the folding surface portion 21 in the folding gap 23. In this way, the bending portion 22 between two adjacent folding gaps 23 is inserted into the U-shaped or V-shaped gap of the folding structure unit 1', close to the bending portion 12 of the folding structure unit 1'.

[0052] In a specific embodiment, Figure 1 As shown in , one end of one of the folding structure units 1' of the first electrode sheet 1 (one of the folding portions 11) is inserted into the fold gap 23a and adhered to the outer surface of the diaphragm 3. The diaphragm 3 is at least adhered to the folded surface of the folding portion 21a in the fold gap 23a. The other end of the folding structure unit 1' (the other folding portion 11) is inserted into another folding gap 23b adjacent to the folding gap 23a of the fan-shaped structure and adhered to the outer surface of the diaphragm 3. At this time, the diaphragm 3 is also at least adhered to the folded surface of the folding portion 21a in the fold gap 23b. In this way, the bending portion 22a between two adjacent folding gaps 23a and 23b is inserted into the U-shaped or V-shaped gap of the folding structure unit 1', close to the bending portion 12 of the folding structure unit 1'.

[0053] One end of another folding structure unit 1' of the first electrode sheet 1 (one of the folding portions 11) is inserted into the fold gap 23c and adhered to the outer surface of the diaphragm 3. The diaphragm 3 at least adheres to the fold surface of the folding portion 21b in the fold gap 23c. The other end of the folding structure unit 1' (the other folding portion 11) is inserted into another fold gap 23d of the folding fan structure adjacent to the fold gap 23c and adhered to the outer surface of the diaphragm 3. At this time, the diaphragm 3 also at least adheres to the fold surface of the folding portion 21b in the fold gap 23d. In this way, the bending portion 22b between two adjacent fold gaps 23c and the fold gap 23d is inserted into the U-shaped or V-shaped gap of the folding structure unit 1', close to the U-shaped or V-shaped bending portion 12 of the folding structure unit 1'.

[0054] In the above-mentioned embodiments, in addition to being attached to at least two opposite folding surfaces of the folding surface 21, in the embodiments, the diaphragm 3 can also be attached to the convex bending surface and / or the concave bending surface of the bending portion 22. In the embodiments of the present invention, it is ideal that the diaphragm 3 is also attached to the convex bending surface and the concave bending surface of the bending portion 22 at the same time to improve the safety performance of the battery cell unit. When the diaphragm 3 is not attached to the convex bending surface and / or the concave bending surface of the bending portion 22, the bending dimensions of the bending portion 12 of the first electrode sheet 1 and the corresponding bending portion 22 of the second electrode sheet 2 should be controlled so that there is a gap between the concave surface of the bending portion 12 and the convex folding surface of the bending portion 22 to avoid short circuit, thereby improving the safety performance of the battery cell unit.

[0055] In a specific embodiment, the diaphragm 3 is a whole diaphragm and is attached to the two opposite surfaces of the second electrode sheet 2. In this way, the diaphragm 3 is attached to the two opposite entire surfaces of the second electrode sheet 2, including the two opposite entire surfaces of the folding portion 21, and also including the convex bending surface and the concave bending surface of the bending portion 22. This effectively improves the safety of the battery cell unit and improves the safety of the battery cell of the embodiment of the present invention.

[0056] In other embodiments, the surface area of ​​the end of the folding structure unit 1' inserted into a fold gap 23 of the folding fan structure is equal to or approximately equal to the folding surface area of ​​the folding portion 21. In this way, the relative area of ​​the first electrode sheet 1 and the second electrode sheet 2 is increased, thereby improving the electrochemical performance of the battery cell unit and improving the safety of the battery cell of the embodiment of the present invention.

[0057] Based on the structure of the battery cell unit in the above embodiments, as one embodiment of the present invention, the second electrode sheet 2 contained in the battery cell unit is a positive electrode sheet. By setting the positive electrode sheet of the battery cell unit to the structure of the second electrode sheet 2 described above, the internal resistance of the battery cell is reduced and the rate performance of the battery cell is improved.

[0058] In a specific embodiment, when the second electrode sheet 2 in the battery cell unit is a positive electrode sheet, the positive electrode sheet is a positive electrode sheet of a lithium-sulfur battery. In this case, the first electrode sheet 1 is a lithium metal sheet. In this way, the battery cell of the present invention containing the battery cell unit constitutes a lithium-sulfur battery cell. In a specific embodiment, the positive electrode sheet of the lithium-sulfur battery includes a current collector and a positive electrode material layer containing active sulfur material and conductive material formed on the surface of the current collector. The lithium metal sheet includes lithium metal foil or lithium metal alloy foil, etc.

[0059] Of course, the first electrode sheet 1 and the second electrode sheet 2 in the above embodiments are respectively provided with tabs. In a specific embodiment, the tabs included in the first electrode sheet 1 are as follows: Figure 2 The pole ear 13 in the middle a figure, the pole ear included in the second electrode sheet 2 is as follows Figure 3 The pole ear 23 in the middle c figure.

[0060] Based on the structure of the battery cell units in the above-mentioned embodiments, the battery cell of the embodiment of the present invention may contain only one battery cell unit described above, and of course may contain more than two battery cell units described above, which can be flexibly controlled according to the actual capacity of the battery cell. In the embodiment, the battery cell may contain 1-200 battery cell units described above, further 1-100, and further 1-50. When the battery cell contains more than two battery cell units described above, the diaphragm 3 is also attached between adjacent battery cell units to isolate the adjacent battery cell units. In another embodiment, when more than two battery cell units are used to assemble the battery cell, each battery cell unit is stacked in sequence along an extension direction. In a specific embodiment, the number of battery cell units of the assembled battery cell can be controlled according to specific needs.

[0061] Therefore, the battery cells contained in the above-mentioned embodiments are configured with the first electrode sheet 1 and the second motor sheet 2 so that the two electrode sheets form an intercalated battery cell structure to enhance synergy, effectively reduce the ohmic resistance of the intercalated battery unit to reduce the ohmic resistance of the battery cell, give the battery cell high safety performance, and effectively overcome the high resistance defect of the existing laminated battery cell, so that the battery cell is suitable for large-capacity batteries.

[0062] Accordingly, an embodiment of the present invention also provides a method for preparing the above battery cell. The method for preparing the battery cell comprises the following steps:

[0063] S01: obtaining a first electrode sheet body, the first electrode sheet body comprising a plurality of electrode sheets, folding each electrode sheet into a U-shape or a V-shape to form a plurality of U-shaped or V-shaped folding structure units to form a first electrode sheet;

[0064] S02: obtaining a second electrode sheet body, and folding the second electrode sheet body into a fan-shaped folding structure; and making the fan-shaped structure have a plurality of folding portions and a plurality of bending portions connecting two adjacent folding portions, so as to form a second electrode sheet;

[0065] S03: Laminating the diaphragm on at least two opposite folded surfaces of the folded surface;

[0066] S04: inserting the folding structure units into the fold gaps of the folding fan structure at intervals and attaching them to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence to form a battery cell unit;

[0067] S05: Assemble at least one battery cell unit into a battery cell.

[0068] The first electrode sheet body in step S01 is formed Figure 1 Each electrode sheet is folded in a U-shape or a V-shape. Figure 2 As shown in Figure a, one section of the electrode sheet 01 is folded into a U-shape or a V-shape along the bending line 14 to form Figure 2 The U-shaped or V-shaped folding structure unit 1' shown in Figure b. In addition, the first electrode sheet body is the electrode sheet body of the first electrode sheet 1 in the above battery cell unit, and specifically, the first electrode sheet body is lithium foil.

[0069] The second electrode sheet body in step S02 is formed Figure 3 The second electrode sheet body is folded in a fan-shaped manner as shown in FIG. Figure 3 As shown in Figure c, the second electrode sheet body 02 is folded in a fan-shaped manner along the bending line 24 to form a Figure 3 The second electrode sheet 2 with a fan-shaped structure is shown in Figure d. In addition, the second electrode sheet body is the electrode sheet body of the second electrode sheet 2 in the battery cell unit described above, and specifically, the second electrode sheet body is a positive electrode sheet of a lithium-sulfur battery.

[0070] In addition, there is no order between step S01 and step S02, and between step S01 and step S03.

[0071] The diaphragm in step S03 is the diaphragm 3 contained in the battery cell unit of the above embodiment of the present invention, wherein the position where the diaphragm is attached to the second electrode sheet is like the position where the diaphragm 3 contained in the above battery cell unit is attached to the second electrode sheet 2, such as at least attached to the two opposite folding surfaces of the folding surface section, and more preferably, attached to the convex bending surface and / or the concave bending surface of the bending portion contained in the folding fan-type structure at the same time.

[0072] The folding structure unit in step S04 is inserted into the fold gap of the folding fan structure and attached to the outer surface of the separator to form an intercalated battery cell unit structure. Figure 1 The first electrode sheet 1 and the second electrode sheet 2 included in the battery cell unit are plugged in an inserting manner to form the above battery cell unit.

[0073] The battery cells in step S05 can be assembled into battery cells according to conventional methods. In the embodiment, when two or more battery cells are used to assemble the battery cells, the adjacent battery cells are separated by a diaphragm 3. In the embodiment, when two or more battery cells are used to assemble the battery cells, each battery cell unit is stacked in sequence along an extending direction. In a specific embodiment, the number of battery cells for assembling the battery cells can be controlled according to specific needs.

[0074] In this way, the above-mentioned battery cell preparation method directly connects the first electrode sheet having a plurality of folding structure units and the second electrode sheet having a folding fan structure according to the intercalation battery cell unit structure to form the battery cell unit of the above-mentioned embodiment of the present invention to assemble to form a battery cell, thereby giving the prepared battery cell unit the characteristics of low ohmic resistance and high safety. In addition, the preparation method of the battery cell of the embodiment of the present invention is easy to control, and the quality and performance of the prepared battery cell are stable and efficient.

[0075] On the other hand, based on the above-mentioned battery cell and its preparation method of the embodiment of the present invention, the embodiment of the present invention also provides a battery. The battery includes a battery cell, and of course also includes necessary components of the battery, such as a battery shell for coating the battery cell and an electrolyte that acts on the battery cell. Among them, the battery cell is the battery cell of the embodiment of the present invention above. Since the battery cell contained in the battery is the battery cell of the embodiment of the present invention above, the battery of the embodiment of the present invention has a small internal resistance, excellent rate performance, high safety, and can also be a large-capacity battery.

[0076] In the embodiment, when the first electrode sheet 1 contained in the battery cell is lithium foil, and the second electrode sheet 2 is a positive electrode, specifically a sulfur-containing battery positive electrode, the battery is a lithium-sulfur battery. When the lithium-sulfur battery is a lithium-sulfur soft-pack battery, the battery structure is as follows: Figure 4 Of course, the battery of the embodiment of the present invention may also be other types of batteries, as long as they contain the battery cells of the embodiment of the present invention described above, they are all within the scope disclosed in the embodiment of the present invention.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery cell, comprising a diaphragm, characterized in that: Also includes: A first electrode sheet, comprising a plurality of U-shaped folding structure units, each of which comprises folding portions at two ends and a U-shaped bending portion connecting the two folding portions, and the U-shaped folding structure refers to a section of the electrode sheet being folded in a U shape; The second electrode sheet comprises a fan-shaped structure formed by folding a whole electrode sheet, the fan-shaped structure having a plurality of folding face portions and a plurality of bending portions connecting two adjacent folding face portions, the diaphragm being attached to at least two folding faces opposite to the folding face portions, the folding structure units being inserted into the folding gaps of the fan-shaped structure at intervals and attached to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence; wherein the bending portion of the fan-shaped structure is U-shaped; The battery cell comprises at least one battery cell unit formed by stacking the first electrode sheet, the separator and the second electrode sheet in sequence, wherein the gap enclosed by the bending portion and the two folding portions in one of the folding structure units in the first electrode sheet is coated on one end of the second electrode, and the gap enclosed by the bending portion and the two folding portions in the other folding structure units are respectively coated on the bending portion of the second electrode sheet; One end of the folding structure unit is inserted into a fold gap of the folding fan structure and fits on the outer surface of the diaphragm, and the other end is inserted into another fold gap of the folding fan structure adjacent to the fold gap and fits on the outer surface of the diaphragm, and the bending part between the two adjacent fold gaps is inserted into the U-shaped gap of the folding structure unit.

2. The battery cell according to claim 1, characterized in that: The diaphragm is also attached to the convex bending surface and / or the concave bending surface of the bending portion.

3. The battery cell according to claim 2, characterized in that: The diaphragm is a whole diaphragm and is attached to two opposite surfaces of the second electrode sheet.

4. The battery cell according to claim 1, characterized in that: The surface area of ​​the end portion of the folding structure unit inserted into the folding gap is equal to or approximately equal to the folding surface area of ​​the folding portion.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The second electrode sheet is a positive electrode sheet; and / or There are more than two battery core units, and the separator is also attached between adjacent battery core units to isolate the adjacent battery core units; and / or There are more than two battery cell units, and the battery cell units are stacked in sequence along an extending direction.

6. The battery cell according to claim 5, characterized in that: The positive electrode sheet is a positive electrode sheet of a lithium-sulfur battery; The first electrode sheet is a lithium metal sheet.

7. A method for preparing a battery cell, comprising the following steps: Obtaining a first electrode sheet body, wherein the first electrode sheet body includes a plurality of sections of electrode sheets, and performing a U-shaped folding process on each section of the electrode sheet to form a plurality of U-shaped folding structure units, so that each of the folding structure units includes folding portions at two ends and a U-shaped bending portion connecting the two folding portions, to form a first electrode sheet; Obtaining a second electrode sheet body, and folding the second electrode sheet body in a fan-shaped manner to form a fan-shaped structure; and making the fan-shaped structure have a plurality of folding portions and a plurality of bending portions connecting two adjacent folding portions to form a second electrode sheet; and the bending portion of the fan-shaped structure is U-shaped; A diaphragm is attached to at least two opposite folded surfaces of the folded surface portion; Insert the folding structure units into the folded gaps of the folding fan-shaped structure at intervals and attach them to the outer surface of the diaphragm, so that the first electrode sheet, the diaphragm and the second electrode sheet are stacked in sequence, and the gap enclosed by the folding portion and the two folding portions in one of the folding structure units in the first electrode sheet is coated on one end of the second electrode, and the gaps enclosed by the folding portions and the two folding portions in other folding structure units are respectively coated on the folding portions of the second electrode sheet, so as to form a battery cell unit; Assembling at least one battery cell unit into a battery cell; One end of the folding structure unit is inserted into a fold gap of the folding fan structure and fits on the outer surface of the diaphragm, and the other end is inserted into another fold gap of the folding fan structure adjacent to the fold gap and fits on the outer surface of the diaphragm, and the bending part between the two adjacent fold gaps is inserted into the U-shaped gap of the folding structure unit.

8. A battery, comprising a battery cell, characterized in that: The battery cell is the battery cell according to any one of claims 1 to 6 or the battery cell prepared by the preparation method according to claim 7.

9. The battery according to claim 8, characterized in that: The battery is a lithium-sulfur battery; or The battery is a lithium-sulfur soft-pack battery.

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