Battery cell assembly, battery cell structure and battery

Abstract

The utility model discloses a battery cell assembly, a battery cell structure and a battery, and belongs to the field of batteries, the battery cell assembly comprises a first electrode and a second electrode, the first electrode comprises a first current collector, a first active coating and a first support coating, a first active matter coating area, a support coating area and a first empty foil area are sequentially arranged on the first current collector in the width direction of the first current collector, and first active coatings are arranged on the first current collector and located on the first active matter coating area and on the two sides of the first current collector in the thickness direction of the first current collector. The first supporting coating is arranged on the first current collector, located in the supporting object coating area and located on the inner side of the battery cell assembly, and the second electrode and the first electrode are arranged in a stacked mode. According to the utility model, in the process of flattening the battery cell assembly, the first supporting coating plays a role in supporting the tabs, so that the risk of short circuit caused by the fact that the tabs are excessively bent towards the interior of the battery cell and are in contact with a counter electrode can be reduced.

Description

Technical Field

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

[0002] With new energy vehicles and other applications placing new demands on batteries for high-rate charge and discharge, conventional single- and bipolar-tab structures can no longer meet the heat dissipation requirements of batteries under high-current charge and discharge conditions. Therefore, existing technologies have developed end-face-welded cylindrical batteries with full-tab designs. Full-tab batteries significantly reduce the internal resistance of the battery, greatly improving the battery's rate charge and discharge performance, reducing the heat generation efficiency of the battery during the charge and discharge process, and increasing the battery's thermal diffusion coefficient, effectively improving the battery's rate performance and safety. The electrode plates of full-tab cylindrical batteries are flattened by a process in which the hollow foil at the edge of the electrode is mechanically pressed inward against the tab. During the flattening process, the deformation of the hollow foil portion of the electrode is uncontrollable, and there is a risk of the tab being excessively bent into the battery cell, causing contact with the counter electrode and short-circuiting. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a battery cell assembly, battery cell structure, and battery in which a support coating is applied to the bare foil area of ​​the electrode. During the flattening process of the battery cell assembly, the support coating supports the tab by pushing it outward, thereby reducing the risk of the tab bending excessively into the battery cell and contacting the counter electrode to short-circuit.

[0004] A battery cell assembly according to an embodiment of the present invention includes:

[0005] A first electrode, comprising a first current collector, a first active coating layer, and a first support coating layer, wherein a first active material coating region, a support coating region, and a first hollow foil region are sequentially provided on the first current collector along its width direction, the first active coating layer is provided on both sides of the first current collector located in the first active material coating region and along its thickness direction, the first support coating layer is provided on the first current collector in the support coating region and on the inner side of the battery cell assembly, and the first support coating layer is used to support the first current collector when the battery cell assembly is flattened;

[0006] a second electrode, stacked with the first electrode;

[0007] A plane parallel to the width direction of the first electrode is defined as a reference plane, a projection of an end of the second electrode close to the first empty foil area on the reference plane forms a line a, a projection of an end of the first supporting coating away from the first active coating on the reference plane forms a line b, and a projection of an end of the first supporting coating close to the first active coating on the reference plane forms a line c, and line a is located between lines b and c.

[0008] A battery cell assembly according to an embodiment of the present invention has at least the following beneficial effects:

[0009] A first supporting coating is provided on the first current collector in the support coating area and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), the first supporting coating supports the tab (the first current collector in the first empty foil area) (pushes the tab outward), which can reduce the risk of the tab being excessively bent toward the inside of the battery cell and short-circuiting with the counter electrode.

[0010] According to some embodiments of the present invention, the first electrode further includes a second supporting coating layer, which is disposed on the first current collector in the support coating region and outside the battery core assembly.

[0011] According to some embodiments of the present invention, the width of the first supporting coating layer is greater than the width of the second supporting coating layer, and the second supporting coating layer is disposed adjacent to the first active coating layer.

[0012] According to some embodiments of the present invention, the width of the first support coating layer is 2-5 mm greater than the width of the second support coating layer.

[0013] According to some embodiments of the present invention, the second electrode includes a second current collector and a second active coating layer, wherein a second active material coating region and a second hollow foil region are sequentially provided on the second current collector along the width direction of the second current collector, and the second active coating layer is provided on both sides of the second current collector located in the second active material coating region and along the thickness direction of the second current collector;

[0014] The projection of one end of the first electrode close to the second empty foil area on the reference plane forms a line d, and the projection of one end of the second active coating close to the second empty foil area on the reference plane forms a line e, which is located on the side of line d away from the center of the battery cell assembly.

[0015] According to some embodiments of the present invention, the width of the second active coating layer is 2-5 mm greater than the width of the first active coating layer.

[0016] According to some embodiments of the present invention, the first support coating layer includes a combination of at least two substances selected from the group consisting of ceramics, polyacrylic acid, PVDF, CMC, and SBR.

[0017] According to some embodiments of the present invention, the battery core assembly is provided with a central hole.

[0018] According to an embodiment of the present invention, a battery cell structure is formed by flattening the battery cell assembly, and the first current collector in the first hollow foil area is bent relative to the first current collector in the first active material coating area.

[0019] A battery cell structure according to an embodiment of the present invention has at least the following beneficial effects:

[0020] A first support coating is provided on the first current collector in the support coating area and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), the first support coating supports the electrode tab, thereby reducing the risk of the electrode tab being excessively bent toward the inside of the battery cell and short-circuiting with the counter electrode.

[0021] A battery according to an embodiment of the present invention includes a shell and the battery core structure, wherein the battery core structure is located inside the shell.

[0022] A battery according to an embodiment of the present invention has at least the following beneficial effects:

[0023] A first support coating is provided on the first current collector in the support coating area and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), the first support coating supports the electrode tab, thereby reducing the risk of the electrode tab being excessively bent toward the inside of the battery cell and short-circuiting with the counter electrode.

[0024] Additional aspects and advantages of the present invention will be described in part in the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic structural diagram of a battery cell assembly according to an embodiment of the present invention;

[0027] Figure 2 A cross-sectional view of a battery cell assembly according to an embodiment of the present invention;

[0028] Figure 3 A top view of a first electrode of a battery cell assembly according to an embodiment of the present invention;

[0029] Figure 4A cross-sectional view of a first electrode of a battery cell assembly according to an embodiment of the present invention;

[0030] Figure 5 A top view of the second electrode of the battery cell assembly according to an embodiment of the present invention;

[0031] Figure 6 A cross-sectional view of the second electrode of the battery cell assembly according to an embodiment of the present invention;

[0032] Figure 7 This is a cross-sectional view of the first electrode of the battery cell structure according to an embodiment of the present invention.

[0033] Figure Number:

[0034] 100, first electrode; 110, first current collector; 111, first active material coating area; 112, support material coating area; 113, first empty foil area; 114, first tab; 120, first active coating layer; 130, first support coating layer; 140, second support coating layer;

[0035] 200, second electrode; 210, second current collector; 211, second active material coating area; 212, second empty foil area; 213, second tab; 220, second active coating;

[0036] 300, diaphragm;

[0037] 400, center hole;

[0038] A. Reference plane, a. Line formed by the projection of one end of the second electrode close to the first empty foil area on the reference plane; b. Line formed by the projection of one end of the first supporting coating away from the first active coating on the reference plane; c. Line formed by the projection of one end of the first supporting coating close to the first active coating on the reference plane; d. Line formed by the projection of one end of the first electrode close to the second empty foil area on the reference plane; e. Line formed by the projection of one end of the second active coating close to the second empty foil area on the reference plane. DETAILED DESCRIPTION

[0039] The following describes embodiments of the present invention in detail. 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 intended only to explain the present invention and are not to be construed as limiting the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They 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. Therefore, they cannot be understood as limitations on the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0042] See also Figure 1 、 Figure 2 and Figure 3 A battery cell assembly according to an embodiment of the present invention includes a first electrode 100, a second electrode 200, and a separator 300. The first electrode 100 includes a first current collector 110, a first active coating layer 120, and a first supporting coating layer 130. A first active coating region 111, a supporting coating region 112, and a first hollow foil region 113 are sequentially provided on the first current collector 110 along the width direction of the first current collector 110. The first active coating layer 120 is provided on both sides of the first active coating region 111 and along the thickness direction of the first current collector 110. The first supporting coating layer 130 is provided on the first current collector 110, located in the supporting coating region 112, and located on the inner side of the battery cell assembly. The first supporting coating layer 130 is used to support the first current collector 110 when the battery cell assembly is flattened. The portion of the first current collector 110 located in the hollow foil region forms a first electrode tab 114. The second electrode 200 is stacked with the first electrode 100 , and the separator 300 is disposed between the first electrode 100 and the second electrode 200 .

[0043] A plane parallel to the width direction of the first electrode 100 is defined as a reference plane A. The projection of the end of the second electrode 200 away from the first active coating layer 120 on the reference plane A forms a line a. The projection of the end of the first supporting coating layer 130 close to the first hollow foil area 113 on the reference plane forms a line b. The projection of the end of the first supporting coating layer 130 away from the first hollow foil area 113 (the junction of the first supporting coating layer 130 and the first active coating layer 120) on the reference plane forms a line c. Line a is located between lines b and c.

[0044] Line a is located on the side of line c away from the center of the battery cell assembly, so that when the first support coating 130 is not applied, during the flattening of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), there is a risk that the first electrode tab 114 will bend excessively toward the inside of the battery cell and short-circuit with the second electrode 200.

[0045] Line b is located on the side of line a away from the center of the battery cell assembly. A first support coating 130 is provided on the first current collector 110 in the support coating area 112 and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), the first support coating 130 supports the first pole ear 114 (pushes the first pole ear 114 outward), which can reduce the risk of the first pole ear 114 being excessively bent toward the inside of the battery cell and short-circuited with the second electrode 200.

[0046] In some embodiments, see Figure 2 、 Figure 3 and Figure 4 The first electrode 100 further includes a second support coating 140, which is disposed on the first current collector 110 in the support coating region 112 and outside the cell assembly. The second support coating 140 is disposed on the first current collector 110 in the support coating region 112 and outside the cell assembly. During the flattening of the cell assembly (the electrode edge foil is bent toward the center of the roll), the second support coating 140 can pull the first tab 114, reducing the risk of the first tab 114 excessively bending toward the interior of the cell and contacting the second electrode 200 to short-circuit.

[0047] In some embodiments, see Figure 2 、 Figure 3 and Figure 4, the width of the first support coating 130 is greater than the width of the second support coating 140, and the second support coating 140 is arranged adjacent to the first active coating 120. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the core), the first support coating 130 pushes the first pole tab 114 outward, and the second support coating 140 pulls the first pole tab 114. Taking advantage of the asymmetry of the force on the pole tab during the flattening process, the two sides of the first pole tab 114 are asymmetrically coated (the width of the first support coating 130 is greater than the width of the second support coating 140), and the force of the extrapolation is greater than the force of the pull, thereby regulating the bending angle of the pole tab during the flattening process of the entire pole tab, and reducing the risk of short circuit of the positive and negative poles of the battery caused by excessive inset of the first pole tab 114 during random bending.

[0048] In some embodiments, see Figure 2 、 Figure 3 and Figure 4 The width of the first support coating 130 is 2-5 mm greater than that of the second support coating 140. Taking advantage of the asymmetry of the forces acting on the tabs during the flattening process, the first tab 114 is asymmetrically coated on both sides. This regulates the tab bending angle during the flattening process and mitigates the risk of battery short circuits caused by excessive inset of the first tab 114 during random bending.

[0049] In some embodiments, see Figure 2 、 Figure 5 and Figure 6 The second electrode 200 includes a second current collector 210 and a second active coating layer 220. A second active material coating region 211 and a second hollow foil region 212 are sequentially arranged on the second current collector 210 along its width. The second active coating layer 220 is provided on both sides of the second current collector 210 located in the second active material coating region 211 and along its thickness. The width of the second active coating layer 220 is greater than the width of the first active coating layer 120. The portion of the second current collector 210 located in the second hollow foil region 212 forms a second electrode tab 213. The first electrode tab 114 and the second electrode tab 213 are located at both ends of the cell assembly along the axial direction of the cell assembly.

[0050] The projection of one end of the first electrode 100 close to the second empty foil area 212 on the reference plane A forms a line d, and the projection of one end of the second active coating layer 220 close to the second empty foil area 212 on the reference plane forms a line e. Line e is located on the side of line d away from the center of the battery cell assembly.

[0051] Line e is located on the side of line d away from the center of the battery cell assembly, so that a portion of the second active coating 220 overflows from the end of the first electrode 100 close to the second empty foil area 212 (the second active coating 220 located between line d and line e). In the process of flattening the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the roll core), the second active coating 220 located between line d and line e supports the second pole ear 213 (pushes and pulls the second pole ear 213), which can reduce the risk of the second pole ear 213 being excessively bent toward the inside of the battery cell and short-circuited with the first electrode 100.

[0052] In some embodiments, see Figure 2 、 Figure 5 and Figure 6 , the width of the second active coating layer 220 is 2-5 mm greater than the width of the first active coating layer 120 .

[0053] Line e is located on the side of line d away from the center of the battery cell assembly, and line a is located on the side of line c toward the center of the battery cell assembly, indicating that the width of the second active coating layer 220 is greater than the width of the first active coating layer 120. Generally, the first electrode 100 is the positive electrode, and the second electrode 200 is the negative electrode. The second active coating layer 220 on the negative electrode is wider than the first active coating layer 120 on the positive electrode. This allows the negative electrode to more effectively absorb and store lithium ions migrating from the positive electrode, reducing the accumulation of lithium ions on the negative electrode surface, thereby reducing the risk of lithium plating.

[0054] In some embodiments, see Figure 2 and Figure 3 The first support coating 130 includes a combination of at least two substances selected from ceramics, polyacrylic acid, PVDF, CMC, and SBR. It can be a combination of two substances or a combination of three, four, or five substances. Ceramics can improve the mechanical strength and stability of the electrode material, polyacrylic acid can be used as a binder), PVDF (Polyvinylidene Fluoride, often used as a binder), CMC (Carboxymethyl Cellulose, sodium carboxymethyl cellulose, which has the function of thickener and binder), SBR (Styrene-Butadiene Rubber, styrene-butadiene rubber, often used as a binder).

[0055] The second support coating layer 140 includes a combination of at least two substances selected from the group consisting of ceramic, polyacrylic acid, PVDF, CMC, and SBR.

[0056] See Figure 1 and Figure 7 A battery cell structure of an embodiment of the present invention is formed by flattening the battery cell assembly, and the first current collector 110 of the first empty foil area 113 is bent relative to the first current collector 110 of the first active material coating area 111.

[0057] A first support coating 130 is provided on the first current collector 110 in the support coating area 112 and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the winding core), the first support coating 130 supports the first pole tab 114, thereby reducing the risk of the first pole tab 114 being excessively bent toward the inside of the battery cell and short-circuited with the second electrode 200.

[0058] See Figure 1 and Figure 2 The battery cell assembly is provided with a central hole 400 , so that the battery cell assembly can be easily flattened, and the empty foil at the electrode edge of the battery cell assembly can be easily bent toward the central hole 400 .

[0059] See Figure 1 and Figure 7 A battery according to an embodiment of the present invention includes a shell and a battery core structure, wherein the battery core structure is located inside the shell.

[0060] A first support coating 130 is provided on the first current collector 110 in the support coating area 112 and on the inner side of the battery cell assembly. During the flattening process of the battery cell assembly (the empty foil at the edge of the electrode is bent toward the center of the winding core), the first support coating 130 supports the first pole tab 114, thereby reducing the risk of the first pole tab 114 being excessively bent toward the inside of the battery cell and short-circuited with the second electrode 200.

[0061] Throughout this specification, reference to terms such as "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 that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell assembly, characterized in that: include: a first electrode, comprising a first current collector, a first active coating layer, and a first supporting coating layer; the first current collector being provided with a first active coating region, a supporting coating region, and a first hollow foil region in sequence along the width direction of the first current collector; the first active coating layer being provided on both sides of the first active coating region and along the thickness direction of the first current collector; and the first supporting coating layer being provided on the supporting coating region and located inside the battery cell assembly; a second electrode, stacked with the first electrode; A plane parallel to the width direction of the first electrode is defined as a reference plane, a projection of an end of the second electrode close to the first empty foil area on the reference plane forms a line a, a projection of an end of the first supporting coating away from the first active coating on the reference plane forms a line b, and a projection of an end of the first supporting coating close to the first active coating on the reference plane forms a line c, and line a is located between lines b and c.

2. A battery core assembly according to claim 1, characterized in that: The first electrode further includes a second supporting coating layer, which is disposed on the first current collector in the support coating region and outside the battery core assembly.

3. A battery core assembly according to claim 2, characterized in that: The width of the first supporting coating layer is greater than the width of the second supporting coating layer, and the second supporting coating layer is disposed adjacent to the first active coating layer.

4. A battery core assembly according to claim 3, characterized in that: The width of the first support coating layer is 2-5 mm greater than the width of the second support coating layer.

5. The battery core assembly according to claim 1, characterized in that: The second electrode includes a second current collector and a second active coating layer, wherein a second active material coating region and a second hollow foil region are sequentially provided on the second current collector along the width direction of the second current collector, and the second active coating layer is provided on both sides of the second current collector located in the second active material coating region and along the thickness direction of the second current collector; The projection of one end of the first electrode close to the second empty foil area on the reference plane forms a line d, and the projection of one end of the second active coating close to the second empty foil area on the reference plane forms a line e, which is located on the side of line d away from the center of the battery cell assembly.

6. A battery core assembly according to claim 5, characterized in that: The width of the second active coating layer is 2-5 mm greater than the width of the first active coating layer.

7. The battery core assembly according to claim 1, characterized in that: The first support coating layer includes a combination of at least two substances selected from the group consisting of ceramics, polyacrylic acid, PVDF, CMC, and SBR.

8. The battery core assembly according to claim 1, characterized in that: The battery core assembly is provided with a central hole.

9. A battery core structure formed by flattening the battery core assembly according to any one of claims 1 to 8, characterized in that: The first current collector in the first hollow foil area is bent relative to the first current collector in the first active material coating area.

10. A battery, characterized in that: The invention comprises a shell and the battery core structure as claimed in claim 9, wherein the battery core structure is located inside the shell.

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