Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell comprises a positive plate, a negative plate, a diaphragm and an adhesive layer, the battery cell has a set length direction, a width direction and a thickness direction, two ends of the battery cell along the length direction are respectively a first end and a second end, the positive plate and the negative plate are provided with tabs, the tabs extend out from the first end, the diaphragm is arranged between the positive plate and the negative plate, and the adhesive layer is arranged between the diaphragm and the negative plate. At least one end of the diaphragm is provided with a bonding part along the length direction of the battery cell, the bonding part exceeds the edge of the negative plate, and the adhesive layer coats the periphery of the bonding part and is bonded to the bonding part, so that the end part of the diaphragm is bonded into an integrated structure, the connection strength is relatively good, and the stability is relatively good; the adhesive layer bonded to the bonding part can prevent the pole piece from moving towards the side where the bonding part is located along the length direction of the battery cell, so that the positive and negative pole pieces and the diaphragm are not misplaced, thereby preventing short circuit in the battery cell caused by contact of the positive and negative pole pieces, and improving the anti-falling performance of the battery cell.

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 the related art, 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, the prior art fixes the diaphragm by pasting a strip of hot melt adhesive on the end of the battery cell to prevent the diaphragm from being misaligned with the pole piece. However, the strip of hot melt adhesive has a weak restraining ability on the diaphragm, and it may still fall off when used for a long time or subjected to a large impact force, and cannot achieve a good protection effect. 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 length direction, width direction and thickness direction, the two ends of the battery cell along the length direction are respectively a first end and a second end, the battery cell has set length direction, width direction and thickness direction, the battery cell comprises a positive electrode sheet, a negative electrode sheet, a diaphragm and a glue layer, 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, along the length direction of the battery cell, at least one end of the diaphragm has a bonding portion, the bonding portion extends beyond the edge of the negative electrode sheet, and the glue layer covers the outer periphery of the bonding portion and is bonded to the bonding portion.

[0006] The battery cell according to the embodiment of the utility model has at least the following beneficial effects: along the length direction of the battery cell, at least one end of the diaphragm has a bonding portion, the bonding portion extends beyond the edge of the negative electrode sheet, the adhesive layer is coated on the periphery of the bonding portion and bonded to the bonding portion, and the ends of the diaphragm are bonded into an integral structure, with good connection strength and good stability. When the battery falls, the adhesive layer bonded to the bonding portion can hinder the movement of the electrode sheet along the length direction of the battery cell toward the side where the bonding portion is located, so that the positive and negative electrode sheets and the diaphragm will not be misaligned, thereby preventing the short circuit in the battery cell caused by the contact between the positive and negative electrode sheets, and improving the anti-drop performance of the battery cell.

[0007] According to some embodiments of the present invention, the adhesive layer is provided with through holes extending along the length direction of the battery core, and the through holes are used to allow electrolyte to flow.

[0008] According to some embodiments of the present invention, the diameter of the through hole is 0.2 mm to 10 mm.

[0009] According to some embodiments of the present invention, there are multiple through holes, and / or the multiple through holes are evenly distributed on the adhesive layer.

[0010] According to some embodiments of the present invention, the sum of the cross-sectional areas of all the through holes accounts for 5% to 50% of the area of ​​the end of the battery cell.

[0011] According to some embodiments of the utility model, the first end of the diaphragm is coated with the glue layer, and the glue layer located at the first end is provided with an avoidance hole, and the avoidance hole penetrates the glue layer along the length direction of the battery cell. The number of the avoidance holes is two, and each of the avoidance holes corresponds to each of the pole ears one by one, and the pole ears are penetrated through the avoidance holes.

[0012] According to some embodiments of the present invention, along the length direction of the battery core, both ends of the extension section have bonding portions.

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

[0014] According to some embodiments of the present invention, the number of the positive electrode sheet and the number of the negative electrode sheet are both plural, and the positive electrode sheet and the negative electrode sheet are stacked in sequence along the thickness direction of the battery cell.

[0015] A battery according to a second embodiment of the present invention includes:

[0016] case;

[0017] The battery cell provided in the first aspect of the embodiment is accommodated in the shell.

[0018] 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.

[0019] 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

[0020] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0021] Figure 1 A top view of a battery cell according to an embodiment of the utility model;

[0022] Figure 2 It is a front view of the battery cell of the utility model embodiment.

[0023] Reference numerals:

[0024] The diaphragm 100 , the bonding portion 110 , the tab 200 , the adhesive layer 300 , the through hole 310 , and the avoidance hole 320 . 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 The first aspect of the utility model provides a battery cell, the battery cell has a set length direction, width direction and thickness direction, the two ends of the battery cell along the length direction are respectively a first end and a second end, the battery cell includes a positive electrode sheet, a negative electrode sheet, a diaphragm 100 and a glue layer 300, the positive electrode sheet and the negative electrode sheet are both provided with a pole ear 200, the pole ear 200 extends from the first end, the diaphragm 100 is arranged between the positive electrode sheet and the negative electrode sheet, the diaphragm 100 includes along the length direction of the battery cell, at least one end of the diaphragm 100 has a bonding portion 110, the bonding portion 110 exceeds the edge of the negative electrode sheet, and the glue layer 300 is coated on the outer periphery of the bonding portion 110. In the manufacturing process of the battery cell, the positive electrode sheet, the negative electrode sheet and the separator 100 are first combined, and the separator 100 has a multi-layer structure at this time. Then, the colloid is dipped at least one end of the separator 100 along the length direction of the battery cell. When dipping, part of the hot melt adhesive will enter between the adjacent layers of the separator 100. Then, the colloid is bonded to the end of the separator 100 and the adjacent layers of the separator 100 through a hot pressing step, thereby achieving bonding and fixing of the end of the separator 100. Among them, the colloid is selected as a hot melt adhesive.

[0031] Along the length direction of the battery cell, at least one end of the diaphragm 100 has a bonding portion 110, and the bonding portion 110 extends beyond the edge of the negative electrode sheet. The adhesive layer 300 is coated on the periphery of the bonding portion 110 and bonded to the bonding portion 110, bonding the ends of the diaphragm 100 into an integrated structure with good connection strength and good stability. When the battery falls, the adhesive layer 300 bonded to the bonding portion 110 can hinder the movement of the electrode sheet along the length direction of the battery cell toward the side where the bonding portion 110 is located, so that the positive and negative electrode sheets and the diaphragm 100 will not be misaligned, thereby preventing the short circuit in the battery cell caused by the contact between the positive and negative electrode sheets, thereby improving the anti-drop performance of the battery cell.

[0032] Reference Figure 2In some embodiments, the adhesive layer 300 is provided with a through hole 310 extending along the length direction of the battery cell, and the through hole 310 is used to allow the electrolyte to flow. When the adhesive layer 300 is bonded to the bonding portion 110, it will block the flow of the electrolyte. Therefore, a through hole 310 extending along the length direction of the battery cell is provided on the colloid, so that when the battery cell is used in a battery, the electrolyte can flow through the through hole 310. The through hole 310 can connect the space between the positive and negative electrode sheets and the diaphragm, thereby ensuring the wettability of the positive and negative electrode sheets, and ensuring the safety and service life of the battery cell. Among them, the processing of the through hole 310 can be achieved by existing processing methods such as drilling or laser drilling.

[0033] Furthermore, the portion of the diaphragm 100 that extends beyond the electrode sheets along the length 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 electrode sheets and the negative electrode sheets, thereby extending the time for lithium deposition to occur in the battery cell and extending the service life of the battery cell when used in the battery.

[0034] In some embodiments, the aperture of the through hole 310 is 0.2 mm to 10 mm. The aperture of the through hole 310 can be selected to be 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or any other value between 0.2 mm and 10 mm. The aperture of the through hole 310 should be neither too large nor too small. When the aperture of the through hole 310 is too small, for example, less than 0.2 mm, although the adhesive layer 300 can achieve good bonding and fixation to the end of the diaphragm 100, the through hole 310 is insufficient in its ability to conduct electrolyte. At this time, in order to ensure the wettability of the electrode, it is necessary to densely process multiple through holes 310 on the adhesive layer 300, which will significantly increase the processing difficulty and cost. When the aperture of the through hole 310 is too large, the strength of the adhesive layer 300 may be low, thereby failing to fix the end of the diaphragm 100 well. Therefore, the aperture of the through hole 310 is selected to be 0.2 mm to 10 mm, which can achieve a balance between the electrolyte passing capacity and the strength of the adhesive layer 300.

[0035] In some embodiments, there are multiple through holes 310, and / or the multiple through holes 310 are evenly distributed on the glue layer 300. The apertures of the multiple through holes 310 can be the same or different. When the apertures of the multiple through holes 310 are the same, the multiple through holes 310 are evenly distributed on the glue layer 300, so as to ensure the wettability of each position of the positive electrode sheet and the negative electrode sheet. When the apertures of the multiple through holes 310 are not equal, the multiple through holes 310 with smaller apertures need to be distributed more densely, while the multiple through holes 310 with larger apertures can be distributed more sparsely, so as to ensure the wettability of the electrode sheet.

[0036] In some embodiments, the spacing between adjacent through holes 310 is 1 to 5 times the aperture of the through hole 310, and the spacing between adjacent through holes 310 is the distance between the axes of the two through holes 310. In order to ensure the wetting effect of the electrolyte on the electrode sheet, the spacing between adjacent through holes 310 needs to be limited to 1 to 5 times the aperture of the through hole 310. For example, the spacing between adjacent through holes 310 can be selected as 1, 2, 3, 4, 5 times or any other value between 1 and 5 times the aperture of the through hole 310. The spacing between adjacent through holes 310 should not be too large or too small. When the spacing between adjacent through holes 310 is too large, some of the electrode sheets between the adjacent through holes 310 may not be fully wetted, affecting the service life and safety of the battery cell. When the spacing between adjacent through holes 310 is too small, the strength of the glue layer 300 may be insufficient, and it may be damaged or broken during use or when subjected to impact force, and lose the ability to fix the end of the diaphragm 100.

[0037] Specifically, the specific value of the spacing between adjacent through holes 310 is related to the aperture of the through hole 310. When the aperture of the through hole 310 is selected to be larger, the spacing between adjacent through holes 310 can also be selected to be larger to ensure the wetting effect of the pole piece. When the aperture of the through hole 310 is selected to be smaller, the spacing between adjacent through holes 310 needs to be selected to be smaller to ensure the wetting effect of the pole piece.

[0038] In some embodiments, the sum of the cross-sectional areas of all through holes 310 accounts for 5% to 50% of the area of ​​the cell end. The sum of the cross-sectional areas of all through holes 310 accounts for 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or any other value between 5% and 50%, while ensuring the wetting effect of the electrode sheet, maintaining the strength of the glue layer 300, and not causing the strength of the glue layer 300 to decrease due to an excessively large perforation area.

[0039] Reference Figure 2In some embodiments, the first end of the diaphragm 100 is coated with a glue layer 300, and the glue layer 300 at the first end is provided with an avoidance hole 320, which penetrates the glue layer 300 along the length direction of the battery cell. There are two avoidance holes 320, each avoidance hole 320 corresponds to each pole lug 200, and the pole lug 200 is penetrated by the avoidance hole 320. In order to avoid the glue layer 300 being coated on the pole lug 200 and affecting the charge and discharge performance of the battery cell, the glue layer 300 at the first end of the battery cell is provided with an avoidance hole 320 for avoiding the pole lug 200, thereby avoiding direct contact between the glue layer 300 and the pole lug 200. Among them, the avoidance hole 320 can be formed by coating the adhesive layer 300 on the first side while avoiding the tab 200, and naturally forming the avoidance hole 320 after the adhesive layer 300 solidifies, or pre-opening the avoidance hole 320 on the solidified adhesive layer 300, and then attaching the adhesive layer 300 to the first side and the tab 200 is passed through the avoidance hole 320, and then performing a hot pressing step on the adhesive layer 300 to achieve bonding between the adhesive layer 300 and the diaphragm 100.

[0040] In some embodiments, the battery cell can be a wound structure battery cell, in which the separator 100, the positive electrode sheet and the negative electrode sheet are wound to form the battery cell. After the separator 100, the positive electrode sheet and the negative electrode sheet are wound to form the battery cell, the colloid is dipped into the ends of the battery cell along the length direction and hot pressed, and after the colloid solidifies, a through hole 310 is opened in the colloid to complete the manufacture of the battery cell.

[0041] In other embodiments, the battery cell may be a stacked structure battery cell, wherein the number of positive and negative electrode sheets are both multiple, and the positive and negative electrode sheets are stacked in sequence along the thickness direction of the battery cell. In this case, the number of diaphragms 100 may be multiple, and each diaphragm 100 includes a bonding portion 110, and a diaphragm 100 is arranged between adjacent positive and negative electrode sheets, and the ends of the multiple diaphragms 100 are bonded together by a glue layer 300, or, the number of diaphragms 100 is one, and the diaphragm 100 is folded in a "Z" shape, and the diaphragm 100 is arranged between the positive electrode sheet and the negative electrode sheet.

[0042] The second embodiment of the utility model provides a battery (not shown in the figure), including a housing and the 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, and the anti-drop performance of the battery cell is improved while the anti-drop performance of the battery is also improved.

[0043] 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 length, width and thickness directions, and the two ends of the battery cell along the length direction are respectively a first end and a second end. The battery cell includes a positive electrode sheet, a negative electrode sheet, a separator and a glue layer. The positive electrode sheet and the negative electrode sheet are both provided with tabs, and the tabs extend from the first end. The separator is arranged between the positive electrode sheet and the negative electrode sheet. Along the length direction of the battery cell, at least one end of the separator has a bonding portion, and the bonding portion extends beyond the edge of the negative electrode sheet. The glue layer covers the periphery of the bonding portion and is bonded to the bonding portion.

2. The battery cell according to claim 1, characterized in that: The adhesive layer is provided with through holes extending along the length direction of the battery core.

3. The battery cell according to claim 2, characterized in that: The aperture of the through hole ranges from 0.2 mm to 10 mm.

4. The battery cell according to claim 2 or 3, characterized in that: The number of the through holes is multiple, and / or the multiple through holes are evenly distributed on the adhesive layer.

5. The battery cell according to claim 4, characterized in that: The spacing between adjacent through holes is 1 to 5 times the diameter of the through holes.

6. The battery cell according to claim 4, characterized in that: The sum of the cross-sectional areas of all the through holes accounts for 5% to 50% of the area of ​​the end of the battery cell.

7. The battery cell according to claim 1, characterized in that: The first end of the diaphragm is coated with the adhesive layer, and the adhesive layer located at the first end is provided with an avoidance hole, and the avoidance hole penetrates the adhesive layer along the length direction of the battery cell. The number of the avoidance holes is two, and each of the avoidance holes corresponds to each of the pole ears one by one, and the pole ears are penetrated through the avoidance holes.

8. The battery cell according to claim 1, characterized in that: The separator, the positive electrode sheet and the negative electrode sheet are wound to form the battery core.

9. The battery cell according to claim 1, characterized in that: There are multiple positive electrode sheets and multiple negative electrode sheets, and the positive electrode sheets and the negative electrode sheets are stacked in sequence along the thickness direction of the battery cell.

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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