Pole group, battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, in particular to a pole group, a battery cell and a battery pack. The pole group comprises a plurality of first polar sheets and a plurality of second polar sheets, the composite material belt comprises diaphragm belts and a second polarity belt, the two diaphragm belts are arranged on the two sides of the second polarity belt in the thickness direction respectively, a plurality of laser nicks arranged at intervals are carved in the length direction of the composite material belt, and the composite material belt located between every two adjacent laser nicks forms a composite pole piece. The composite material belt is bent along the laser nicks, so that every two adjacent composite pole pieces are arranged at an included angle, the first polar pieces stretch into the included angles, and the first polar pieces and the included angles are arranged in a one-to-one correspondence mode. According to the invention, the laser nicks are arranged, so that the composite material belt forms a foldable material belt structure, and the cutting process of the pole piece is omitted, so that short circuit caused by foreign matters such as residues generated by cutting is avoided, and the lamination speed and the production yield and production efficiency of the pole group are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to an electrode group, a battery cell and a battery pack. Background Art

[0002] Lithium-ion batteries, due to their excellent energy density, long life, lack of memory effect, and rapid charging capabilities, are widely used in a wide range of fields, including portable electronic devices, electric vehicles, the aerospace industry, and large-scale energy storage systems. To manufacture a battery, a slurry of electrode active material is first applied to the positive and negative current collectors to prepare the positive and negative electrodes stacked on either side of the separator, forming an electrode assembly with a predetermined shape. The electrode assembly is then housed in a battery casing, electrolyte is injected, and the battery is sealed. Existing thermal lamination processes require cutting the negative electrode strip into negative electrode sheets, which are then fed between two layers of separators. The negative electrode sheets and the separators, as well as the separators at the edges of the negative electrode sheets, are bonded together using a specific temperature and pressure. After cutting, the sheets are alternately stacked with the positive electrode sheets to form an electrode assembly. Negative electrode sheets are cut using hardware, which can easily produce foreign matter such as negative electrode residue, causing short circuits. Furthermore, the alignment between the negative electrode sheet and the separator must be controlled during the composite unit preparation, resulting in low yield and low production efficiency. Summary of the Invention

[0003] In view of this, the purpose of the present application is to provide an electrode group, a battery cell and a battery pack to solve the problem that the existing electrode group is prone to produce negative electrode residues and other foreign matter during the process of cutting the negative electrode sheet, causing short circuits, and the operation is complicated and requires controlling the alignment between the negative electrode sheet and the diaphragm, resulting in low production yield and efficiency.

[0004] A first aspect of the present invention provides an electrode group, wherein the electrode group comprises:

[0005] A plurality of first polarity plates are provided;

[0006] A composite material strip includes a diaphragm strip and a second polarity strip, the two diaphragm strips are respectively arranged on both sides of the second polarity strip in the thickness direction, and a plurality of spaced laser marks are engraved in the length direction of the composite material strip. The composite material strip located between two adjacent laser marks is formed into a composite pole piece, and the composite material strip is bent along the laser marks so that the two adjacent composite pole pieces are arranged at an angle. After the composite material strip is bent, the first polar piece extends into the angle, and the first polar piece is arranged in a one-to-one correspondence with the angle. After the first polar piece extends into the angle, the first polar piece and the composite pole piece are stacked so that the composite pole piece fits the surface of the first polar piece.

[0007] Preferably, the bending directions of two adjacent laser marks are opposite.

[0008] Preferably, the first polarity sheet is a positive electrode sheet, and the first polarity sheet is formed into a polygonal sheet structure.

[0009] Preferably, the composite electrode sheet includes a negative electrode sheet and a diaphragm sheet arranged on both sides of the negative electrode sheet.

[0010] Preferably, the negative electrode plate is provided with a protruding negative electrode tab, and the negative electrode tab extends out of the edge of the diaphragm plate.

[0011] Preferably, before the laser scoring is provided on the composite material strip, the two diaphragm strips and the second polarity strip are brought together and passed through the gap between two pressing rollers.

[0012] Preferably, the laser scoring forms an intermittently arranged strip structure, and the laser scoring includes a plurality of through holes penetrating the composite material strip, and the plurality of through holes are arranged at intervals along the length direction of the laser scoring.

[0013] Preferably, the length direction of the laser scoring is perpendicular to the extension direction of the composite material strip.

[0014] A second aspect of the present invention provides a battery cell comprising the electrode group described in any one of the above technical solutions.

[0015] A third aspect of the present invention provides a battery pack comprising the battery cell described in the above technical solution.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The electrode group of the present invention includes a first polar sheet and a composite material strip; the composite material strip includes a diaphragm strip and a second polar sheet, the two diaphragm strips are respectively arranged on both sides of the thickness direction of the second polar sheet, and a plurality of spaced laser notches are provided in the length direction of the composite material strip. The composite material strip located between two adjacent laser notches forms a composite electrode sheet, and the composite material strip is bent along the laser notches so that the two adjacent composite electrode sheets are arranged at an angle. After the composite material strip is bent, the first polar sheet extends into the angle, and after the first polar sheet extends into the angle, the first polar sheet and the composite electrode sheet are stacked so that the composite electrode sheet is bonded to the surface of the first polar sheet. The laser notches are provided so that the composite material strip forms a folded material strip structure, thereby eliminating the need for cutting the electrode sheet, thereby avoiding short circuits caused by foreign matter such as residues generated by cutting, and in the process of bending and folding the sheet, there is no need to consider alignment, nor is there any need to consider factors such as overhang (i.e., the portion of the negative electrode sheet that exceeds the positive electrode sheet in the length and width directions), thereby improving the stacking speed and the production yield and production efficiency of the electrode group, thereby improving the safety performance and production quality of the battery cell and battery pack.

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic structural diagram of the angle at which the first polar sheet in the electrode group extends into the composite material strip provided by an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the structure of a composite material strip formed by combining the separator strip and the second polarity strip in the electrode group provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the structure of laser scoring on a composite material strip in an electrode group provided in an embodiment of the present invention.

[0023] Icons: 10-first polar sheet; 20-composite material strip; 201-diaphragm strip; 202-second polar strip; 21-laser scoring; 22-composite pole sheet; 221-negative pole sheet; 2210-negative pole tab; 222-diaphragm sheet; 23-angle; 30-pressing roller. DETAILED DESCRIPTION

[0024] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent upon understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, except for operations that must occur in a particular order, changes may be made that will be apparent upon understanding the disclosure of this application. Furthermore, descriptions of features known in the art may be omitted for clarity and brevity.

[0025] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways to implement the methods, devices, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0026] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, it may be directly “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on,” “directly connected to,” “directly coupled to,” “directly over,” or “directly covering” another element, there may be no other elements intervening therebetween.

[0027] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0028] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, a first member, component, region, layer, or portion in the examples described herein may also be referred to as a second member, component, region, layer, or portion without departing from the teachings of the examples.

[0029] For ease of description, spatial relational terms such as "above," "upper," "below," and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element would subsequently be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientations "above" and "below," depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0030] The terms used herein are intended only to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" list the presence of stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0031] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include changes in shapes that occur during manufacturing.

[0032] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0033] According to a first aspect of the present invention, a pole group is provided, which includes a first polar sheet 10 and a composite material strip 20 .

[0034] Hereinafter, the specific structures of the above-mentioned components of the electrode group according to the present embodiment will be described.

[0035] In this embodiment, if Figure 1 As shown, a plurality of first polarity plates 10 are provided, and the first polarity plates 10 are formed into a sheet-like structure. For example, the first polarity plates 10 can be formed into a rectangular sheet-like structure.

[0036] In this embodiment, if Figures 1 to 3 As shown, the composite material strip 20 includes a diaphragm strip 201 and a second polarity strip 202. The diaphragm strip 201 and the second polarity strip 202 are both formed into a strip structure, that is, a structure in which the length dimension is much larger than the width dimension. Before the diaphragm strip 201 and the second polarity strip 202 are combined, the diaphragm strip 201 and the second polarity strip 202 can be wound into a roll.

[0037] like Figure 1 and Figure 2 As shown, two diaphragm tapes 201 are provided, and the expanded parts of the two diaphragm tapes 201 are respectively arranged on both sides of the expanded part of the second polar tape 202 in the thickness direction, so that the second polar tape 202 is sandwiched between the two diaphragm tapes 201 to form a composite material tape 20 structure stacked into three layers.

[0038] Furthermore, in this embodiment, Figure 1 and Figure 3As shown, a plurality of spaced laser marks 21 are provided in the length direction of the composite material strip 20. The composite material strip 20 located between two adjacent laser marks 21 is formed into a composite pole piece 22. The composite material strip 20 is bent along the laser marks 21 so that the two adjacent composite pole pieces 22 are arranged at an angle 23. After the composite material strip 20 is bent, the first polarity piece 10 extends into the angle 23. The first polarity piece 10 is arranged in a one-to-one correspondence with the angle 23. After the first polarity piece 10 extends into the angle 23, the first polarity piece 10 and the composite pole piece 22 are stacked so that the diaphragm piece 222 is away from the negative pole piece 2 One side of 21 is bonded to the surface of the first polar sheet 10 to form a pole group. In the present application, a laser notch 21 is provided so that the composite material strip 20 is formed into a foldable material strip structure, thereby eliminating the cutting process, thereby avoiding short circuits caused by foreign matter such as residues generated by cutting, reducing the risk of short circuits, and ensuring the safety of the battery cell; in addition, in the process of bending and folding the sheets, there is no need to consider alignment, nor is there any need to consider factors such as overhang (i.e., the portion of the negative electrode sheet 221 that exceeds the positive electrode sheet in the length and width directions), thereby improving the stacking speed and the production yield and production efficiency of the pole group.

[0039] In a preferred embodiment, Figure 2 As shown, the laser score 21 thermally fuses the membrane tape 201 and the second polar tape 202. Before the laser score 21 is formed on the composite tape 20, the two membrane tapes 201 and the second polar tape 202 are brought together and passed through the gap between two pressing rollers 30. This compacts the composite tape 20 and facilitates the subsequent processing and forming of the laser score 21. The pressing rollers 30 are formed into a rotatable drum-like structure to convey the composite tape 20.

[0040] In this embodiment, if Figure 1 As shown, the bending directions of two adjacent laser marks 21 are opposite, so that the folded composite material strip 20 forms a Z-shaped reciprocating folding structure to facilitate the assembly of the first polar sheet 10.

[0041] Specifically, in this embodiment, the first polar plate 10 is a positive electrode plate.

[0042] More specifically, in this embodiment, if Figures 1 to 3 As shown, the composite electrode sheet 22 includes a negative electrode sheet 221 and a diaphragm sheet 222 arranged on both sides of the negative electrode sheet 221, so that the composite electrode sheet 22 forms a sandwich structure with the negative electrode sheet 221 in the middle and the diaphragm sheets 222 on both sides.

[0043] Furthermore, in this embodiment, Figure 3 As shown, a protruding negative electrode tab 2210 is provided on the negative electrode plate 221 , and part of the negative electrode tab 2210 extends out of the edge of the diaphragm plate 222 to facilitate the connection of the tab and meet the requirements of power transmission.

[0044] In this embodiment, if Figure 3 As shown, the laser score 21 is formed into a discontinuous strip structure, for example, a dashed line or a dot-dash line. Specifically, the laser score 21 includes a plurality of through holes extending through the composite strip 20. The plurality of through holes are spaced apart along the length of the laser score 21. Each through hole can be formed into an elongated hole, with the length of the elongated hole aligning with the length of the laser score 21. This increases the heat-melting area between the diaphragm strip 201 and the second polarity strip 202, facilitating bending.

[0045] In a preferred embodiment, Figure 3 As shown, the length direction of the laser score 21 is perpendicular to the extension direction of the composite material strip 20, so that the composite pole piece 22 is formed into a rectangular sandwich structure, which meets the clamping requirements of the first polarity piece 10, saves materials and avoids the situation where the negative pole piece 221 exceeds the positive pole piece in the length and width directions.

[0046] According to the present invention, a pole group is provided, comprising a first polarity sheet and a composite material strip; the composite material strip comprises a diaphragm strip and a second polarity strip, the two diaphragm strips are respectively arranged on both sides of the second polarity strip in the thickness direction, and a plurality of spaced laser notches are provided in the length direction of the composite material strip, the composite material strip located between two adjacent laser notches forms a composite pole piece, the composite material strip is bent along the laser notches so that the two adjacent composite pole pieces are arranged at an angle, the first polarity sheet extends into the angle, and the laser notches are provided so that the composite material strip forms a folded material strip structure, thereby eliminating the need for cutting the pole piece, thereby avoiding short circuits caused by foreign matter such as residues generated by cutting, and in the process of bending and folding the sheets, there is no need to consider alignment, nor is there any need to consider factors such as overhang (i.e., the portion of the negative pole piece that exceeds the positive pole piece in the length and width directions), thereby improving the stacking speed and the production yield and production efficiency of the pole group.

[0047] According to a second aspect of the present invention, a battery cell is provided, comprising the electrode group as described above, and the short-circuit risk of the electrode group is reduced, thereby improving the performance and safety of the battery cell.

[0048] According to a third aspect of the present invention, a battery pack is provided, comprising the battery cell described above. A plurality of battery cells are connected to form a battery module. The battery module is disposed in a housing of the battery pack, thereby improving the safety performance of the battery pack.

[0049] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. These modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims.

Claims

1. An electrode group, characterized in that: The pole group includes: A plurality of first polarity plates are provided; A composite material strip includes a diaphragm strip and a second polarity strip, the two diaphragm strips are respectively arranged on both sides of the second polarity strip in the thickness direction, and a plurality of spaced laser marks are engraved in the length direction of the composite material strip. The composite material strip located between two adjacent laser marks is formed into a composite pole piece, and the composite material strip is bent along the laser marks so that the two adjacent composite pole pieces are arranged at an angle. After the composite material strip is bent, the first polar piece extends into the angle, and the first polar piece is arranged in a one-to-one correspondence with the angle. After the first polar piece extends into the angle, the first polar piece and the composite pole piece are stacked so that the composite pole piece fits the surface of the first polar piece.

2. The electrode group according to claim 1, characterized in that The bending directions of two adjacent laser marks are opposite.

3. The electrode group according to claim 1, characterized in that: The first polar plate is a positive electrode plate.

4. The electrode group according to claim 1, characterized in that: The composite electrode sheet includes a negative electrode sheet and a diaphragm sheet arranged on both sides of the negative electrode sheet.

5. The electrode group according to claim 4, characterized in that: The negative electrode plate is provided with a protruding negative electrode tab, and the negative electrode tab extends out from the edge of the diaphragm plate.

6. The electrode group according to claim 1, characterized in that: Before the laser scoring is provided on the composite material strip, two diaphragm strips and a second polarity strip are brought together and passed through a gap between two pressing rollers.

7. The electrode group according to claim 1, characterized in that: The laser scoring forms an intermittently arranged strip structure. The laser scoring includes a plurality of through holes penetrating the composite material strip. The plurality of through holes are arranged at intervals along the length direction of the laser scoring.

8. The electrode group according to claim 7, characterized in that: The length direction of the laser scoring is perpendicular to the extension direction of the composite material strip.

9. A battery cell, characterized in that: Comprising the electrode group according to any one of claims 1 to 8.

10. A battery pack, characterized in that: Comprising the battery cell according to claim 9.

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