Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell has the set height direction, width direction and thickness direction, the battery cell comprises a positive plate, a negative plate, a diaphragm and a suture line, the diaphragm is arranged between the positive plate and the negative plate, and the two ends of the diaphragm exceed the edges of the positive plate and the negative plate along the height direction of the battery cell. The part, exceeding the positive plate and the negative plate, of the diaphragm comprises a sewing part, and the sewing line penetrates through the sewing part in the thickness direction of the battery cell and sews the sewing part in the width direction of the battery cell. When the battery falls off, the suture line can hinder the trend of moving away from the diaphragm on the side where the suture part is located in the height direction of the battery cell, so that short circuit in the battery cell caused by contact of positive and negative pole pieces is prevented, and the service life of the battery cell is prolonged. Meanwhile, the stability of the suture line is good, and the suture line cannot lose efficacy after being used for a long time.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, in particular to a battery core and a battery. Background Art

[0002] In related technologies, drop resistance is one of the important safety indicators for evaluating secondary batteries. Generally, the battery is tested through a drop test. After the battery falls, the diaphragm may be folded or misaligned with the pole piece, resulting in direct contact between pole pieces of different polarities and internal short circuit, followed by a large amount of heat in the battery and even fire. In order to avoid the above situation, some technologies use hot melt adhesive to adhere to both ends of the battery cell to fix the diaphragm and prevent the diaphragm from misaligning with the pole piece. However, the hot melt adhesive may still fall off after long-term use and is not stable enough. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a battery core that can prevent the pole piece and the diaphragm from being misaligned and has good stability.

[0004] The utility model also provides a battery having the battery core.

[0005] According to the battery cell of the first aspect embodiment of the utility model, the battery cell has set height direction, width direction and thickness direction, the two ends of the battery cell along the height direction are respectively a first end and a second end, the battery cell comprises a positive electrode sheet, a negative electrode sheet, a diaphragm and a stitching line, the positive electrode sheet and the negative electrode sheet are both provided with a pole ear, the pole ear extends from the first end, the diaphragm is arranged between the positive electrode sheet and the negative electrode sheet, at least one end of the diaphragm along the height direction of the battery cell has a stitching portion, the stitching portion extends beyond the edge of the negative electrode sheet, the stitching line passes through the stitching portion along the thickness direction of the battery cell, and the stitching line stitches the stitching portion along the width direction of the battery cell.

[0006] The battery cell according to the embodiment of the utility model has at least the following beneficial effects: the diaphragm includes a stitching portion, the stitching portion extends beyond the edge of the negative electrode sheet along the height direction of the battery cell, the stitching line passes through the stitching portion along the thickness direction of the battery cell, and the stitching line stitches the stitching portion along the width direction of the battery cell, so that the multi-layer diaphragms in the stitching portion are connected as a whole through the stitching line, and when the battery falls, the stitching line can hinder the movement of the diaphragm along the height direction of the battery cell away from the stitching portion, thereby preventing a short circuit in the battery cell caused by contact between the positive and negative electrodes, and at the same time, the stitching line has good stability, which is beneficial to extending the service life.

[0007] According to some embodiments of the present invention, the suture line penetrates the suture portion along the thickness direction of the battery core to form suture holes, and along the width direction of the battery core, a distance D between adjacent suture holes is 1 mm to 5 mm.

[0008] According to some embodiments of the present invention, along the height direction of the battery core, the size of the stitching portion is 0.5 mm to 3.5 mm.

[0009] According to some embodiments of the present invention, the size of the suture portion is 1.0 mm to 1.5 mm.

[0010] According to some embodiments of the present invention, the suture line penetrates the suture part along the thickness direction of the battery core to form a suture hole, and the hole diameter of the suture hole is less than or equal to half of the size of the suture part along the height direction of the battery core.

[0011] According to some embodiments of the utility model, when the diaphragm is provided with a suture portion at the first end, the diaphragm further includes an avoidance portion, the avoidance portion is provided corresponding to the pole lug, and along the width direction of the battery cell, the size of the avoidance portion is larger than the size of the pole lug.

[0012] According to some embodiments of the present invention, along the height direction of the battery core, both ends of the diaphragm have the stitching parts, and the stitching parts at both ends of the diaphragm are stitched by the stitching lines respectively.

[0013] According to some embodiments of the present invention, the positive electrode sheet, the separator and the negative electrode sheet are wound to form the battery core.

[0014] According to some embodiments of the present invention, there are plural positive electrode sheets and plural negative electrode sheets, the positive electrode sheets and the negative electrode sheets are stacked in sequence, and the separator is arranged between adjacent positive electrode sheets and negative electrode sheets.

[0015] The battery according to the second embodiment of the utility model comprises a housing and the battery cell provided by the first embodiment, wherein the battery cell is accommodated in the housing.

[0016] The battery according to the embodiment of the utility model has at least the following beneficial effects: the battery includes the battery cell provided by the above-mentioned first aspect embodiment, and at least has all the advantages of the battery cell, and while the drop resistance of the battery cell is improved, the drop resistance of the battery is also improved.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0019] Figure 1 A schematic diagram of a battery cell according to an embodiment of the utility model;

[0020] Figure 2 for Figure 1 Magnified view of area “A”;

[0021] Reference numerals:

[0022] Diaphragm 100, suture portion 110, avoidance portion 120;

[0023] Suture line 200, suture hole 210;

[0024] Tab 300. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0026] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0030] Reference Figure 1 and Figure 2 According to a first aspect of the utility model, an embodiment provides a battery cell, which has a set height direction, width direction and thickness direction. The battery cell comprises a positive electrode sheet, a negative electrode sheet, a separator 100 and a stitching line 200. The two ends of the battery cell along the height direction are respectively a first end and a second end. Both the positive electrode sheet and the negative electrode sheet are provided with a pole ear 300, and the pole ear 300 extends from the first end. The separator 100 is arranged between the positive electrode sheet and the negative electrode sheet. Along the height direction of the battery cell, at least one end of the separator 100 has a stitching portion 110, and the stitching portion 110 exceeds the edge of the negative electrode sheet. The stitching line 200 penetrates the stitching portion 110 along the thickness direction of the battery cell, and the stitching line 200 stitches the stitching portion 110 along the width direction of the battery cell.

[0031] The diaphragm 100 has a stitching part 110, and the stitching part 110 exceeds the edge of the negative electrode sheet. The stitching line 200 penetrates the stitching part 110 along the thickness direction of the battery cell, and the stitching line 200 stitches the stitching part 110 along the width direction of the battery cell, so that the multi-layer diaphragm 100 in the stitching part 110 is connected as a whole through the stitching line 200. When the battery falls, the stitching line 200 can hinder the movement of the diaphragm 100 along the height direction of the battery cell to the side away from the stitching part 110, thereby preventing the positive and negative electrode sheets from contacting and causing a short circuit in the battery cell. At the same time, the stitching line 200 has good stability, which is conducive to extending the service life. The stitching line 200 penetrates the stitching part 110 along the thickness direction of the battery cell to form a stitching hole 210. When the battery cell is used in a battery, the electrolyte can flow into the gap between the stitching part 110 between adjacent stitching holes 210 and infiltrate the positive and negative electrode sheets, thereby avoiding the lithium precipitation problem caused by insufficient electrolyte infiltration.

[0032] In addition, the portion of the diaphragm 100 that extends beyond the electrode sheets along the height direction of the battery cell can store electrolyte. When the electrolyte decreases in the later stage of the battery cycle, the portion of the diaphragm 100 that extends beyond the electrode sheets can still provide a certain amount of electrolyte for the positive and negative electrode sheets, thereby extending the time for lithium deposition to occur in the battery cell and extending the service life of the battery.

[0033] Reference Figure 2In some embodiments, along the width direction of the battery cell, the distance D between adjacent suture holes 210 is 1 mm to 5 mm. Since the suture thread 200 is only sutured to the suture portion 110, the distance between adjacent suture holes 210 refers to the distance between adjacent suture holes 210 in the same suture portion 110. The spacing between adjacent suture holes 210 can be selected to be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or any other value between 1 mm and 5 mm.

[0034] The distance between adjacent suture holes 210 cannot be too large or too small. When the spacing between adjacent suture holes 210 is too large, for example, greater than 5 mm, although the electrolyte can ensure sufficient infiltration of the positive and negative electrodes, the portion of the diaphragm 100 between the adjacent suture holes 210 is not subjected to sufficient restraint from the suture line 200, and may still fold when it falls, thereby causing contact between the positive and negative electrodes. When the spacing between adjacent suture holes 210 is too small, for example, less than 1 mm, although the suture line 200 can have a good restraining effect on the sutured portion 110 of the diaphragm 100, it is difficult for the electrolyte to flow in from between the adjacent suture holes 210, resulting in insufficient infiltration of some areas of the positive and negative electrodes. As the battery cell is used, the possibility of lithium deposition in the areas where the positive and negative electrodes are not sufficiently infiltrated increases, which may reduce the service life of the battery cell.

[0035] In some embodiments, along the height direction of the battery cell, the size of the stitching portion 110 is 0.5mm to 3.5mm. The size of the stitching portion 110 can be selected as 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm or any other value between 0.5mm and 3.5mm. The size of the stitching portion 110 is the distance from the edge of the stitching portion 110 to the edge of the negative electrode sheet. Since errors and fluctuations may occur in the starting position of the stitching and the stitching process when the stitching line 200 is stitched, the stitching portion 110 needs to reserve enough space for the stitching of the stitching line 200, so as to ensure the stitching effect of the stitching line 200. However, the size of the stitching portion 110 should not be too large. If the size of the stitching portion 110 along the height direction of the battery cell is too large, the energy density of the battery will decrease when the battery cell is used in the battery.

[0036] Specifically, the suture position of the suture line 200 is the middle area of ​​the suture part 110 along the height direction of the battery cell, that is, the area where the distance from the edge of the positive and negative electrode sheets and the edge of the suture part 110 away from the positive and negative electrode sheets along the height direction of the battery cell is approximately equal, so as to ensure that the suture line 200 will not penetrate into the positive and negative electrode sheets to cause damage to the positive and negative electrode sheets during the suture process, and will not be too close to the edge of the suture part 110 to cause leakage during the suture process. It is understandable that after the suture is completed, the part between the position of the suture line 200 and the edge of the diaphragm 100 can be removed, so as to further improve the energy density of the battery cell when it is used in the battery.

[0037] Furthermore, the size of the stitching portion 110 along the height direction of the battery cell is 1.0 mm to 1.5 mm. The size of the stitching portion 110 can be selected to be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm or any other value between 1.0 mm and 1.5 mm. When the size of the stitching portion 110 is selected between 1.0 mm and 1.5 mm, it can ensure that there is enough space for the stitching line 200 to be stitched, and the energy density of the battery will not be greatly reduced when the battery cell is used in the battery, so that the battery safety performance is guaranteed without significantly reducing the battery performance.

[0038] In some embodiments, the suture thread 200 penetrates the suture portion 110 along the thickness direction of the battery cell to form a suture hole 210, and the aperture of the suture hole 210 is less than or equal to half of the size of the suture portion 110 along the height direction of the battery cell. For example, when the size of the suture portion 110 is selected to be 0.5mm to 3.5mm, the aperture of the suture hole 210 is selected to be 0.25mm to 1.75mm, so that the suture thread 200 will not exceed the edge of the diaphragm 100 during suture, thereby ensuring the connection strength between the suture thread 200 and the diaphragm 100. The aperture of the suture hole 210 can be selected to be 0.25mm, 0.5mm, 0.75mm, 1.00mm, 1.25mm, 1.50mm, 1.75mm or any other value between 0.25mm and 1.75mm.

[0039] Reference Figure 1In some embodiments, when the diaphragm 100 is provided with a stitching portion 110 at the first end, the diaphragm 100 further includes an escape portion 120, which is provided corresponding to the tab 300, and the size of the escape portion 120 is larger than the size of the tab 300 along the width direction of the battery cell. Specifically, two escape portions 120 are provided corresponding to the two tabs 300 respectively, and the edges of both sides of the escape portion 120 exceed the edges of both sides of the tab 300 by at least 1 mm along the width direction of the battery cell. There are three stitching portions 110, which are provided on the side of the tab 300 that is away from each other and between the two tabs 300. The stitching line 200 only stitches the stitching portion 110, so that the tab 300 will not be penetrated by the stitching hole 210, thereby ensuring the integrity of the tab 300. The diaphragm 100 at the second end of the battery cell only includes the stitching portion 110, and the stitching line 200 continuously stitches the stitching portion 110 at the second end along the length direction of the battery cell.

[0040] Reference Figure 1 In some embodiments, along the height direction of the battery cell, both ends of the separator 100 have stitching parts 110, and the stitching parts 110 at both ends of the separator 100 are stitched by stitching lines 200. When the battery cell is used in a battery, the stitching lines 200 on both sides can prevent the separator 100 from moving in a large range relative to the positive electrode sheet and the negative electrode sheet, and can prevent the separator 100 from turning inward, thereby avoiding failure caused by contact between the positive electrode sheet and the negative electrode sheet.

[0041] In some embodiments, the suture 200 is made of one or more of cotton, silk and synthetic fibers. The suture 200 needs to have a certain strength, good insulation and not react with the electrolyte when immersed in the electrolyte environment, so as to ensure the long-term use of the suture 200.

[0042] In some embodiments, the positive electrode sheet, the separator 100 and the negative electrode sheet are wound to form a battery cell. The battery cell may be a wound structure battery cell. After the positive electrode sheet, the negative electrode sheet and the separator 100 are synchronously wound, the sewing part 110 of the separator 100 is sewn by the sewing thread 200, thereby improving the anti-drop performance of the battery cell and reducing the possibility of failure of the battery cell.

[0043] In other embodiments, there are multiple positive and negative electrode sheets, which are stacked in sequence, and the separator 100 is disposed between adjacent positive and negative electrode sheets. The battery cell may be a laminated structure battery cell. Specifically, the separator 100 may be an integral structure having a certain length, which separates adjacent positive and negative electrode sheets by folding in a Z shape; or, there may be multiple separators 100, and a separator 100 is disposed between adjacent positive and negative electrode sheets. After the positive electrode sheet, the negative electrode sheet and the separator 100 are stacked, the sewing portion 110 of the separator 100 is sewn by the suture line 200, thereby improving the anti-drop performance of the battery cell and reducing the possibility of failure of the battery cell.

[0044] The second embodiment of the utility model provides a battery (not shown in the figure), including a housing and a battery cell provided by the first embodiment. The battery cell is accommodated in the housing. The battery includes the battery cell provided by the first embodiment, and at least has all the advantages of the battery cell. While the anti-drop performance of the battery cell is improved, the anti-drop performance of the battery is also improved.

[0045] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A battery cell, characterized in that: The battery cell has set height, width and thickness directions, and the two ends of the battery cell along the height direction are respectively a first end and a second end. The battery cell includes a positive electrode sheet, a negative electrode sheet, a diaphragm and a stitching line. The positive electrode sheet and the negative electrode sheet are both provided with a pole ear, and the pole ear extends from the first end. The diaphragm is arranged between the positive electrode sheet and the negative electrode sheet. At least one end of the diaphragm along the height direction of the battery cell has a stitching portion, and the stitching portion extends beyond the edge of the negative electrode sheet. The stitching line passes through the stitching portion along the thickness direction of the battery cell, and the stitching line stitches the stitching portion along the width direction of the battery cell.

2. The battery cell according to claim 1, characterized in that: The suture line penetrates the suture part along the thickness direction of the battery core to form suture holes, and along the width direction of the battery core, a distance D between adjacent suture holes is 1 mm to 5 mm.

3. The battery cell according to claim 1, characterized in that: Along the height direction of the battery core, the size of the stitching portion is 0.5 mm to 3.5 mm.

4. The battery cell according to claim 3, characterized in that: The size of the sutured portion is 1.0 mm to 1.5 mm.

5. The battery cell according to claim 3, characterized in that: The stitching line penetrates the stitching part along the thickness direction of the battery core to form a stitching hole, and the hole diameter of the stitching hole is less than or equal to half of the size of the stitching part along the height direction of the battery core.

6. The battery cell according to claim 1, characterized in that: The diaphragm is provided with a stitching portion and an escape portion at the first end. The escape portion is provided corresponding to the tab. Along the width direction of the battery cell, the stitching portion is located on at least one side of the escape portion. The size of the escape portion is larger than the size of the tab.

7. The battery cell according to any one of claims 1 to 6, characterized in that: Along the height direction of the battery core, both ends of the diaphragm have the sutured parts, and the sutured parts at both ends of the diaphragm are sutured by the suture lines respectively.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The positive electrode sheet, the separator and the negative electrode sheet are wound to form the battery cell.

9. The battery cell according to any one of claims 1 to 6, characterized in that: There are multiple positive electrode sheets and multiple negative electrode sheets, which are stacked in sequence, and the separator is arranged between adjacent positive electrode sheets and negative electrode sheets.

10. A battery, characterized in that include: case; The battery cell according to any one of claims 1 to 9 is accommodated in the shell.

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