Battery cell and electronic equipment

Abstract

The utility model relates to the technical field of batteries, in particular to a battery cell and electronic equipment. The battery cell comprises a first pole piece and a second pole piece, a plurality of first opening parts are arranged on one side of the first pole piece at intervals in the length direction of the first pole piece, the polarity of the second pole piece is opposite to that of the first pole piece, a plurality of second opening parts are arranged on one side of the second pole piece at intervals in the length direction of the second pole piece, and the polarity of the second opening parts is opposite to that of the second pole piece. Wherein the first pole piece and the second pole piece are overlapped, the first opening part and the second opening part are oppositely arranged to form a folding area, and the first pole piece and the second pole piece are wound in the folding area to form a wound battery cell. The electronic equipment comprises the battery cell. According to the battery cell and the electronic equipment, the electrical performance of the battery cell is optimized, and the service life of the battery cell is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a battery cell and an electronic device. Background Art

[0002] Lithium-ion batteries are widely used in the field of consumer electronics due to their advantages such as long cycle life, low self-discharge, light weight, and environmental friendliness. There are many structures of lithium-ion battery cells, and among them, the wound structure is the mainstream structure of current consumer battery cells. With the increasing variety of electronic products, the requirements for the size of battery cells are also different, including some battery cell sizes with relatively thick thickness and more winding layers. The thicker the battery cell and the more winding layers, the more likely it is to cause wrinkles at the corner positions of the battery cell during packaging, and the electrolyte is not easily infiltrated into the interior of the battery cell, which will affect the electrical performance of the battery cell and thus deteriorate the life of the battery cell. Summary of the Utility Model

[0003] The main purpose of the utility model is to propose a battery cell and an electronic device, aiming to solve the technical problems that as the designed thickness of the battery cell increases and the number of winding layers increases, it is more likely to cause wrinkles at the corner positions of the battery cell during packaging and poor infiltration of the electrolyte.

[0004] To achieve the above purpose, the utility model proposes a battery cell, including:

[0005] A first pole piece, along the length direction of the first pole piece, a plurality of first opening parts are spacedly arranged on one side of the first pole piece;

[0006] A second pole piece, the second pole piece has a polarity opposite to that of the first pole piece, along the length direction of the second pole piece, a plurality of second opening parts are spacedly arranged on one side of the second pole piece;

[0007] Wherein, the first pole piece and the second pole piece are stacked, and the first opening parts and the second opening parts are arranged opposite to each other to form a folding area, and the first pole piece and the second pole piece are wound in the folding area to form a wound battery cell.

[0008] In some embodiments, the first pole piece is a negative pole piece, a negative electrode active material layer is provided on the surface of the first pole piece, the second pole piece is a positive pole piece, and a positive electrode active material layer is provided on the surface of the second pole piece.

[0009] In some embodiments, a separator is provided between the first pole piece and the second pole piece, and the separator separates the first pole piece and the second pole piece.

[0010] In some embodiments, along the width direction of the battery cell before winding, the distance H between the opposite ends of the first opening part 1, the distance H between opposite ends of the second opening portion 2 , and the distance H between opposite ends of the battery cell 3 satisfy: 0.2 mm < H 2 - H 1 < 1 mm < H 3 .

[0011] In some embodiments, along the length direction of the battery cell before winding, the distance W between opposite ends of the first opening portion 1 , the distance W between opposite ends of the second opening portion 2 , and the distance W between opposite ends of the battery cell 3 satisfy: 0.2 mm < W 2 - W 1 < 1 mm < W 3 .

[0012] In some embodiments, the specific capacity per gram of the negative electrode active material layer is higher than that of the positive electrode active material layer.

[0013] In some embodiments, the negative electrode active material layer is at least one of a silicon-carbon composite structure or a high specific capacity graphite structure, and the positive electrode active material layer is at least one of a lithium cobalt oxide structure, a lithium iron phosphate structure, and a lithium manganese iron phosphate structure.

[0014] In some embodiments, the first opening portion and the second opening portion are an elliptical hole structure, a square hole structure, or a triangular hole structure.

[0015] In some embodiments, along the length direction of the first electrode sheet, a plurality of the first opening portions are spaced apart on both opposite sides of the first electrode sheet, and along the length direction of the second electrode sheet, a plurality of the second opening portions are spaced apart on both opposite sides of the second electrode sheet.

[0016] Correspondingly, the present invention further provides an electronic device including the battery cell according to any one of the above embodiments.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] In the technical solution of the present utility model, before winding the battery cell, a plurality of first opening portions are arranged at intervals on one side edge of the first pole piece, and a plurality of second opening portions are arranged at intervals on one side edge of the second pole piece. Then, the first pole piece and the second pole piece are laminated, and the first opening portions are aligned with the second opening portions. When winding the battery cell, the first pole piece and the second pole piece are wound in the area where the first opening portions and the second opening portions are provided, ensuring that the area where the first opening portions and the second opening portions are provided corresponds to the end corners of the battery cell after winding. This will make the thickness of the end corners of the battery cell thinner, effectively avoiding the scraping of the end corners of the battery cell by the housing when the battery cell is encapsulated into the housing, thereby effectively preventing the pole pieces at the end corners of the battery cell from wrinkling and affecting the safety and electrical performance of the battery cell. In addition, the thinning of the end corners of the battery cell is also beneficial to the rapid infiltration of the electrolyte into the interior of the battery cell, improving the infiltration effect of the electrolyte, and thus conducive to improving the cycle performance of the battery cell.

[0019] The battery cell provided by the present utility model is conducive to improving the safety of the battery cell during encapsulation, enhancing the electrolyte infiltration effect after encapsulation of the battery cell, thereby optimizing the electrical performance of the battery cell and extending the service life of the battery cell.

[0020] The electronic device applying the above battery cell has good battery performance and a long battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 It is an exploded view of the structure of the battery cell provided by an embodiment of the present utility model;

[0023] Figure 2 It is a front view of the structure of the battery cell provided by an embodiment of the present utility model;

[0024] Figure 3 It is a schematic diagram of the structure parameters of the battery cell provided by an embodiment of the present utility model.

[0025] Explanation of the reference numerals in the drawings:

[0026] 100 - First pole piece;

[0027] 110 - First opening portion;

[0028] 200 - Second pole piece;

[0029] 210 - Second opening portion;

[0030] 300 - Diaphragm;

[0031] X - The length direction of the battery cell before winding;

[0032] Y - The width direction of the battery cell before winding.

[0033] The realization, functional features and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0035] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0036] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear throughout the text, their meanings include three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0037] Lithium-ion batteries are widely used in the consumer electronics field due to their advantages such as long cycle life, low self-discharge, light weight, and environmental friendliness. There are many structures of lithium-ion battery cells, among which the wound structure is the mainstream structure of current consumer battery cells. With the increasing variety of electronic products, the requirements for the size of battery cells are also different, including some battery cell sizes with relatively thick thickness and more winding layers. The thicker the battery cell thickness and the more winding layers, the more likely it is to cause wrinkles at the corner positions of the battery cell during battery cell encapsulation, and the electrolyte is not easily infiltrated into the interior of the battery cell, which will affect the electrical performance of the battery cell and thus deteriorate the life of the battery cell.

[0038] To solve the technical problems that as the designed thickness of the battery cell increases and the number of winding layers increases, it is more likely to cause wrinkles at the corner positions of the battery cell during battery cell encapsulation and is likely to cause poor electrolyte infiltration, referring to Figures 1 to 3 a battery cell provided by an embodiment of the present utility model includes a first pole piece 100 and a second pole piece 200. Along the length direction of the first pole piece 100, a plurality of first opening parts 110 are arranged at intervals on one side of the first pole piece 100. The second pole piece 200 has the opposite polarity to the first pole piece 100. Exemplarily, for example, if the first pole piece 100 is a positive pole piece, then the second pole piece 200 is a negative pole piece; if the first pole piece 100 is a negative pole piece, then the second pole piece 200 is a positive pole piece. Along the length direction of the second pole piece 200, a plurality of second opening parts 210 are arranged at intervals on one side of the second pole piece 200. Among them, the first pole piece 100 and the second pole piece 200 are stacked, and the first opening parts 110 and the second opening parts 210 are arranged opposite to each other to form a folding area. The first pole piece 100 and the second pole piece 200 are wound in the folding area to form a wound battery cell.

[0039] Specifically, to solve the above problems, in this embodiment, before winding the battery cell, a plurality of first opening parts 110 are arranged at intervals on one side edge of the first pole piece 100, and a plurality of second opening parts 210 are arranged at intervals on one side edge of the second pole piece 200. Then, the first pole piece 100 and the second pole piece 200 are laminated, and the first opening parts 110 are aligned with the second opening parts 210. When winding the battery cell, the first pole piece 100 and the second pole piece 200 are wound in the area where the first opening parts 110 and the second opening parts 210 are arranged, ensuring that the area where the first opening parts 110 and the second opening parts 210 are arranged after winding the battery cell corresponds to the end corners of the battery cell. This will make the thickness of the end corners of the battery cell thinner, effectively avoiding the shell from scraping the end corners of the battery cell when the battery cell is encapsulated into the shell, thereby effectively avoiding the wrinkles of the pole pieces at the end corners of the battery cell and affecting the safety and electrical performance of the battery cell. In addition, the thinning of the end corners of the battery cell is also beneficial to the rapid infiltration of the electrolyte into the interior of the battery cell, improving the infiltration effect of the electrolyte, and thus being beneficial to improving the cycle performance of the battery cell.

[0040] The battery cell provided by this embodiment is beneficial to improving the safety of the battery cell during encapsulation, enhancing the electrolyte infiltration effect after encapsulation of the battery cell, thereby optimizing the electrical performance of the battery cell and extending the service life of the battery cell.

[0041] In some embodiments, referring to Figure 1 , the first electrode sheet 100 is a negative electrode sheet, and a negative electrode active material layer (not shown in the figure) is provided on the surface of the first electrode sheet 100. The second electrode sheet 200 is a positive electrode sheet, and a positive electrode active material layer (not shown in the figure) is provided on the surface of the second electrode sheet 200.

[0042] Specifically, in this embodiment, the negative electrode active material layer can be a graphite structure, and the positive electrode active material layer can be a lithium-containing compound structure. Exemplarily, for example, the positive electrode active material layer can be a lithium cobalt oxide structure or a lithium iron phosphate structure, etc. When the battery cell is working normally, lithium ions are continuously deintercalated and intercalated between the negative electrode active material layer and the positive electrode active material layer, thereby realizing the charge and discharge of the battery cell.

[0043] Furthermore, the first electrode sheet 100 can be slightly wider than the second electrode sheet 200, or the first electrode sheet 100 can also be slightly longer than the second electrode sheet 200, so that the negative electrode active material layer coated on the first electrode sheet 100 is more than the positive electrode active material layer coated on the second electrode sheet 200. Thus, when the battery cell is charging, it is ensured that the negative electrode active material layer can provide sufficient intercalation space for lithium ions, avoiding the phenomenon of lithium deposition on the first electrode sheet 100 and affecting the use safety of the battery cell.

[0044] In some embodiments, referring to Figure 1 , a separator 300 is provided between the first electrode sheet 100 and the second electrode sheet 200, and the separator 300 separates the first electrode sheet 100 and the second electrode sheet 200.

[0045] Specifically, in order to ensure the use safety of the battery cell, in this embodiment, the first electrode sheet 100 and the second electrode sheet 200 can be completely separated by the separator 300, avoiding direct contact between the first electrode sheet 100 and the second electrode sheet 200 and causing an internal short circuit of the battery cell, thereby being beneficial to eliminating the safety hazard during the use of the battery cell and avoiding causing safety problems.

[0046] It should be noted that in order to ensure the isolation effect of the separator 300 on the first electrode sheet 100 and the second electrode sheet 200, no holes are made in the separator 300 to ensure the integrity of the separator 300.

[0047] In some embodiments, referring to Figure 3 , along the width direction Y of the battery cell before winding, the distance H between the opposite ends of the first opening portion 110 1 (assuming it is the width H of the first opening portion 110 1) The distance H between opposite ends of the second opening portion 210 2 (Assumed to be the width H of the second opening portion 210 2 ), and the distance H between opposite ends of the battery cell 3 (Assumed to be the width H of the battery cell 3 ) satisfy: 0.2 mm < H 2 - H 1 < 1 mm < H 3 .

[0048] Specifically, in order to ensure that lithium is not deposited on the first electrode 100 when the battery cell is charged, in this embodiment, the width dimensions of the first opening portion 110 and the second opening portion 210 are limited, that is, the width dimension of the first opening portion 110 is smaller than the width dimension of the second opening portion 210. With such a structure, it can be ensured that the empty foil area formed around the first opening portion 110 is larger than the empty foil area formed around the second opening portion 210. When coating the active material layer on the first electrode 100 and the second electrode 200, it can be ensured that the negative active material layer coated around the first opening portion 110 is more than the positive active material layer coated around the second opening portion 210, thereby improving the lithium intercalation ability of the first electrode 100 at the opening portion position, effectively avoiding the occurrence of lithium deposition at the opening portion position, and ensuring the use safety of the battery cell.

[0049] In some embodiments, the width dimensions of the first opening portion 110, the second opening portion 210, and the battery cell satisfy the above relationship. On the one hand, it can avoid the excessive difference in width dimensions between the first opening portion 110, the second opening portion 210, and the battery cell, which may affect the winding effect of the battery cell and cause unevenness at the winding position of the battery cell. On the other hand, it can also avoid the too small difference in width dimensions between the first opening portion 110, the second opening portion 210, and the battery cell, which may affect the coating amount of the active material layer on the first electrode 100 and the second electrode 200 and easily lead to the occurrence of lithium deposition at the opening portion position.

[0050] In some embodiments, referring to Figure 3 , along the length direction X of the battery cell before winding, the distance W between opposite ends of the first opening portion 110 1 (Assumed to be the length W of the first opening portion 110 1 ), the distance W between opposite ends of the second opening portion 210 2 (Assumed to be the length W of the second opening portion 210 2 ), and the distance W between opposite ends of the battery cell 3 (Assumed to be the length W of the battery cell 3 ) satisfy: 0.2 mm < W 2 - W 1 < 1 mm < W 3。

[0051] Specifically, referring to the above embodiments, in order to ensure that lithium is not deposited on the first electrode 100 during the charging of the battery cell, in this embodiment, the length dimensions of the first opening portion 110 and the second opening portion 210 are limited, that is, the length dimension of the first opening portion 110 is smaller than the length dimension of the second opening portion 210. With such a structure, it can be ensured that the empty foil area formed around the first opening portion 110 is larger than the empty foil area formed around the second opening portion 210. When coating the active material layer on the first electrode 100 and the second electrode 200, it can be ensured that the negative active material layer coated around the first opening portion 110 is more than the positive active material layer coated around the second opening portion 210, thereby improving the lithium intercalation ability of the first electrode 100 at the opening portion, effectively avoiding the occurrence of lithium deposition at the opening portion, and ensuring the use safety of the battery cell.

[0052] In some embodiments, the length dimensions of the first opening portion 110, the second opening portion 210, and the battery cell satisfy the above relationship. On the one hand, it can avoid too large a difference in the length dimensions between the first opening portion 110, the second opening portion 210, and the battery cell, which may affect the winding effect of the battery cell and cause unevenness at the winding position of the battery cell. On the other hand, it can also avoid too small a difference in the length dimensions between the first opening portion 110, the second opening portion 210, and the battery cell, which may affect the coating amount of the active material layer on the first electrode 100 and the second electrode 200 and easily lead to the occurrence of lithium deposition at the opening portion.

[0053] In some embodiments, the positions of the nth first opening portion 110 of the first electrode 100 and the nth second opening portion 210 of the second electrode 200 both satisfy: L n = L 1 +(n - 1)*L, where L is the width increase per turn relative to the previous turn.

[0054] In some embodiments, the specific capacity of the negative active material layer is higher than that of the positive active material layer.

[0055] Specifically, in order to improve the lithium intercalation capacity of the negative electrode sheet (i.e., the first electrode sheet 100) and avoid lithium deposition on the negative electrode sheet (i.e., the first electrode sheet 100), in this embodiment, the active material layers coated on the surfaces of the first electrode sheet 100 and the second electrode sheet 200 are improved. According to the formula "design capacity of the battery cell = coating surface density * active material ratio * specific capacity of the active material * coated area of the electrode sheet", it can be known that when other parameters are fixed, the design capacity of the battery cell can be increased by increasing the specific capacity of the active material layer. Therefore, in order to prevent lithium deposition on the first electrode sheet 100, the capacity of the first electrode sheet 100 to accommodate lithium ions is generally overdesigned, so that the ability of the first electrode sheet 100 to accommodate lithium ions is higher than that of the second electrode sheet 200 to accommodate lithium ions, to ensure that all the lithium ions deintercalated from the second electrode sheet 200 can be absorbed by the first electrode sheet 100, and will not cause lithium ions to be free on the surface of the first electrode sheet 100, avoiding the precipitation of lithium metal on the surface of the first electrode sheet 100 after the free lithium ions gain electrons, which may then pierce the separator 300 between the first electrode sheet 100 and the second electrode sheet 200, resulting in direct contact between the first electrode sheet 100 and the second electrode sheet 200, causing an internal short circuit in the battery cell and threatening the safety of the battery cell during use.

[0056] In some embodiments, the negative electrode active material layer is at least one of a silicon-carbon composite structure or a high-specific-capacity graphite structure, and the positive electrode active material layer is at least one of a lithium cobaltate structure, a lithium iron phosphate structure, and a lithium manganese iron phosphate structure.

[0057] Exemplarily, for example, the negative electrode active material layer can be a silicon-carbon composite structure, or the negative electrode active material layer can also be a high-specific-capacity graphite structure, or the negative electrode active material layer can also be a composite layer of a silicon-carbon composite structure and a high-specific-capacity graphite structure. The positive electrode active material layer can be a lithium cobaltate structure, or the positive electrode active material layer can also be a lithium iron phosphate structure, or the positive electrode active material layer can also be a composite layer of a lithium cobaltate structure and a lithium iron phosphate structure.

[0058] In some embodiments, referring to Figures 1 to 3 , the first opening portion 110 and the second opening portion 210 are an elliptical hole structure, a square hole structure, or a triangular hole structure. It should be noted that the structures of the first opening portion 110 and the second opening portion 210 can be adaptively designed according to production requirements.

[0059] In some embodiments, referring to Figures 1 to 3 , along the length direction of the first electrode sheet 100, a plurality of first opening portions 110 are spaced apart on both opposite sides of the first electrode sheet 100, and along the length direction of the second electrode sheet 200, a plurality of second opening portions 210 are spaced apart on both opposite sides of the second electrode sheet 200.

[0060] Specifically, referring to the above embodiments, in this embodiment, along the length direction of the electrode tab, a plurality of opening portions are spaced apart on both opposite sides of the electrode tab, which can ensure that the thicknesses at the four end corners of the wound battery cell become thinner. Furthermore, it can effectively prevent the housing from scraping the four end corners of the battery cell when the battery cell is encapsulated into the housing, and avoid the electrode tabs at the four end corners of the battery cell from wrinkling, which may affect the safety and electrical performance of the battery cell. In addition, the thinning of the four end corners of the battery cell is more conducive to the rapid infiltration of the electrolyte into the interior of the battery cell, more conducive to improving the infiltration effect of the electrolyte, and more conducive to enhancing the cycle performance of the battery cell.

[0061] Correspondingly, another embodiment of the present invention further provides an electronic device, which includes the battery cell in any of the above embodiments.

[0062] Specifically, in this embodiment, the electronic device can be a camera, a mobile phone, etc. The electronic device using the above battery cell has good battery performance and a long battery life.

[0063] Benefiting from the improvement of the above battery cell, the electronic device in this embodiment has the same technical effects as the above battery cell, which will not be elaborated here.

[0064] It should be noted that other contents of the battery cell and the electronic device disclosed in the present invention can be referred to the prior art, which will not be elaborated here.

[0065] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A battery cell, characterized in that: include: A first pole piece, wherein a plurality of first opening portions are arranged at intervals on one side of the first pole piece along a length direction of the first pole piece; A second pole piece, wherein the second pole piece has opposite polarity to the first pole piece, and a plurality of second openings are arranged at intervals on one side of the second pole piece along the length direction of the second pole piece; The first pole piece and the second pole piece are overlapped, and the first opening portion and the second opening portion are arranged opposite to each other to form a folding area, and the first pole piece and the second pole piece are wound in the folding area to form a wound battery cell.

2. The battery cell according to claim 1, characterized in that: The first pole piece is a negative pole piece, and a negative active material layer is disposed on the surface of the first pole piece. The second pole piece is a positive pole piece, and a positive active material layer is disposed on the surface of the second pole piece.

3. The battery cell according to claim 2, characterized in that: A diaphragm is disposed between the first pole piece and the second pole piece, and the diaphragm separates the first pole piece and the second pole piece.

4. The battery cell according to claim 2, characterized in that: Along the width direction of the battery cell before winding, the distance H1 between the two opposite ends of the first opening portion, the distance H2 between the two opposite ends of the second opening portion, and the distance H3 between the two opposite ends of the battery cell satisfy: 0.2mm<H2-H1<1mm<H3.

5. The battery cell according to claim 2, characterized in that: Along the length direction of the battery cell before winding, the distance W1 between the two opposite ends of the first opening portion, the distance W2 between the two opposite ends of the second opening portion, and the distance W3 between the two opposite ends of the battery cell satisfy: 0.2mm<W2-W1<1mm<W3.

6. The battery cell according to claim 2, characterized in that: The gram capacity of the negative electrode active material layer is higher than the gram capacity of the positive electrode active material layer.

7. The battery cell according to claim 6, characterized in that: The negative electrode active material layer is a silicon-carbon composite layer or a high-gram capacity graphite layer, and the positive electrode active material layer is a lithium cobalt oxide layer, a lithium iron phosphate layer or a lithium manganese iron phosphate layer.

8. The battery cell according to claim 1, characterized in that: The first opening portion and the second opening portion are elliptical hole structures, square hole structures or triangular hole structures.

9. The battery cell according to any one of claims 1 to 8, characterized in that: Along the length direction of the first pole piece, a plurality of first openings are arranged at intervals on two opposite sides of the first pole piece, and along the length direction of the second pole piece, a plurality of second openings are arranged at intervals on two opposite sides of the second pole piece.

10. An electronic device, characterized in that A battery cell comprising the battery cell according to any one of claims 1 to 9.

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