Pole piece, battery cell and battery

Abstract

The pole piece is provided with a first side and a second side which are opposite to each other along the width direction of the pole piece, the edge of the first side is used for mounting a tab, a coating area is formed on the pole piece, and the thickness of at least part of the coating area on the first side is smaller than that of the second side. According to the pole piece, the battery cell and the battery disclosed by the utility model, the overall flatness of the battery cell can be improved, the packaging of the battery cell is facilitated, and the activation of the battery cell is facilitated after the battery cell is assembled into the battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a pole piece, electric core and battery. BACKGROUND

[0002] The electric core of lithium battery is assembled and formed, and due to the influence of the thickness of the pole lug, the thickness size of the side of the electric core provided with the pole lug is greater than the thickness size of the opposite side, thereby reducing the flatness of the whole electric core, which not only affects the packaging of the electric core, but also affects the activation of the electric core after the electric core is assembled into a battery. SUMMARY

[0003] The utility model discloses at least one of the technical problems in the prior art is solved, and therefore the utility model provides a pole piece, which can improve the flatness of the whole electric core, is beneficial to the packaging of the electric core, and is beneficial to the activation of the electric core after the electric core is assembled into a battery.

[0004] The utility model discloses further provide a kind of electric core with above-mentioned pole piece.

[0005] The utility model discloses further provide a kind of battery with above-mentioned electric core.

[0006] According to the pole piece of the first aspect embodiment of the utility model, the pole piece has opposite first side and second side along the width direction of itself, the edge of the first side is used to install pole lug, the pole piece is formed with coating area, and the thickness size of the coating area in at least partial area of the first side is less than the thickness size of the second side.

[0007] According to the pole piece of the utility model embodiment, at least has following beneficial effect:

[0008] The pole lug is installed on the edge of the first side of the pole piece, and then the pole piece and the diaphragm are stacked and wound to form the electric core. Since the thickness size of the coating area in at least partial area of the first side of the pole piece is less than the thickness size of the second side, that is, the thickness size of at least partial area of the side of the coating area close to the pole lug is less than the thickness size of the opposite side, and then after forming the electric core, even if the thickness of the pole lug is affected, the thickness difference of the two sides in the width direction of the electric core is small, so that the flatness of the whole electric core can be improved, which is beneficial to the packaging of the electric core, and is beneficial to the activation of the electric core after the electric core is assembled into a battery.

[0009] According to some embodiments of the utility model, the thickness size of the coating area in all areas of the first side is less than the thickness size of the second side.

[0010] According to some embodiments of the utility model, the thickness size of the coating area gradually increases from the first side to the second side.

[0011] According to some embodiments of the present application, the edge of the first side is provided with a mounting groove, and the mounting groove is used for mounting the tab.

[0012] According to some embodiments of the present application, the tab includes a current collector and two coating layers, the two coating layers are respectively coated on two surfaces of the current collector in the thickness direction to form the coating area together with the current collector, at least one end of the current collector in the length direction protrudes from the coating layer to form a tab area, and the tab area is provided with the mounting groove.

[0013] According to some embodiments of the present application, the thickness dimension of the coating layer gradually increases from the first side to the second side.

[0014] According to the battery of the third aspect of the present application, the battery includes the battery cell of the second aspect of the present application.

[0015] According to the battery of the third aspect of the present application, the battery includes the battery cell of the second aspect of the present application.

[0016] The battery cell of the second aspect of the present application adopts the tab of the first aspect of the present application, which can improve the flatness of the battery cell as a whole, is beneficial to the packaging of the battery cell, and is beneficial to the activation of the battery cell after the battery cell is assembled into a battery.

[0017] According to some embodiments of the present application, the thickness dimension of the coating area on the first side is H1, the thickness dimension of the coating area on the second side is H2, the number of layers of the tab along the thickness direction of the battery cell is n, and the thickness dimension of the tab is T, and the following condition is met: T = n x (H2-H1), wherein H1

[0018] According to some embodiments of the present application, the thickness difference between the second side and the first side of the coating area meets the following condition: 0.85 μm ≤ H2-H1 ≤ 6 μm.

[0019] According to the battery of the third aspect of the present application, the battery includes the battery cell of the second aspect of the present application.

[0020] According to the battery of the third aspect of the present application, the battery includes the battery cell of the second aspect of the present application.

[0021] The battery of the second aspect of the present application adopts the battery cell, and the battery cell of the first aspect of the present application adopts the tab, which can improve the flatness of the battery cell as a whole, is beneficial to the packaging of the battery cell, and is beneficial to the activation of the battery cell after the battery cell is assembled into a battery.

[0022] Additional aspects and advantages of the present application will be given in part in the following description and will be apparent from the description, or will be learned by practice of the present application. The present application will be realized by the methods that are set forth in the appended claims and combinations thereof. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described by the following description and embodiments in conjunction with the accompanying drawings, in which:

[0024] Figure 1 is a structural schematic view of the pole piece of one embodiment of the present application;

[0025] Figure 2 is a sectional view of Figure 1

[0026] Figure 3 is a structural schematic view of the pole piece of another embodiment of the present application;

[0027] Figure 4 is a sectional view of Figure 3

[0028] Figure 5 is a schematic view of thickness variation of the coating area along the width direction;

[0029] Figure 6 is a schematic view of thickness of the existing battery cell;

[0030] Figure 7 is a schematic view of thickness of the battery cell of the embodiment of the present application.

[0031] REFERENCE NUMERALS:

[0032] Pole piece 10; coating area 11; tab area 12; first side 13; second side 14; mounting groove 15;

[0033] Current collector 100;

[0034] Coating layer 200;

[0035] Tab 20. DETAILED DESCRIPTION

[0036] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are only used to explain the present application and cannot be understood as limiting the present application.

[0037] ​​In the description of the utility model, it needs to be understood that, when the direction description, such as the direction or position relation indicated by up, down etc. is based on the direction or position relation shown in the drawing, it is only for the convenience of describing the utility model and simplifying the description, and it is not indicated or implied that the device or element indicated must have a particular direction, a particular direction structure and operation, therefore it can not be understood as the limitation of the utility model.

[0038] In the description of the utility model, multiple means two or more than two. If the first, second is described for the purpose of distinguishing technical features, it can not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0039] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, installation, connection etc. should be understood broadly, and the technical personnel in the technical field can determine the specific meaning of the above words in the utility model in combination with the specific content of the technical scheme.

[0040] With the development of science and technology, lithium battery is more and more widely used in consumer electronics and new energy vehicles and other fields. After the lithium battery cell is assembled and formed, due to the influence of the thickness of the tab itself, the thickness size of the side of the cell provided with the tab is greater than that of the opposite side, and the thickness size difference is large, which reduces the flatness of the whole cell, not only affects the packaging of the cell, but also affects the activation of the cell after the cell is assembled into a battery.

[0041] Therefore, the utility model provides a tab, a cell and a battery, which can effectively improve the above problems.

[0042] The following refers to Figures 1 to 7 The tab, the cell and the battery according to the utility model embodiment are described.

[0043] Reference Figures 1 to 5 As shown in the figure, according to the tab 10 of the first aspect embodiment of the utility model, the tab 10 has opposite first side 13 and second side 14 along the width direction of itself, the edge of the first side 13 of the tab 10 is used for installing the tab 20, and the tab 10 is formed with coating area 11.

[0044] Among them, the coating area 11 is coated with active material, and the thickness size of the coating area 11 in at least part of the area of the first side 13 is less than that of the second side 14, for example, along the length direction of the tab 10, the thickness size of the coating area 11 in all areas of the first side 13 can be less than that of the second side 14, or the thickness size of the coating area 11 in part of the area of the first side 13 can be less than that of the second side 14.

[0045] The utility model discloses a first side 13 of the pole piece 10 is connected with the tab 20, and then the pole piece 10 and the diaphragm are laminated and are wound, can form the electric core. Figure 6 The existing electric core shown in the drawing is influenced by the thickness of the tab 20, so that the thickness dimension of one side of the electric core provided with the tab 20 is greater than the thickness dimension of the opposite side, as shown in the drawing. Figure 7 The utility model discloses an electric core, because the thickness dimension of the at least partial area of the coating area 11 of the pole piece 10 on the first side 13 is less than the thickness dimension of the second side 14, that is, the thickness dimension of the at least partial area of the coating area 11 on one side close to the tab 20 is less than the thickness dimension of the opposite side, and after forming the electric core, even if influenced by the thickness of the tab 20, the thickness difference of the two sides in the width direction of the electric core is small, so that the flatness of the whole electric core can be improved, which is not only beneficial to the packaging of the electric core, but also beneficial to the activation of the electric core after the electric core is assembled into a battery.

[0046] As shown in the drawing, in some embodiments of the utility model, the thickness dimension of all areas of the coating area 11 on the first side 13 is less than the thickness dimension of the second side 14. Figure 5 For example, the thickness dimension of the first side 13 of the coating area 11 can be equal, the thickness dimension of the second side 14 of the coating area 11 can be equal, the thickness dimension of all areas of the coating area 11 on the first side 13 along the length direction of the pole piece 10 is less than the thickness dimension of all areas of the coating area 11 on the second side 14 along the length direction of the pole piece 10, so that when the pole piece 10 is wound to form the electric core, the thickness difference of the two sides in the width direction of the electric core can be further reduced, so that the flatness of the whole electric core can be further improved, which is not only more beneficial to the packaging of the electric core, but also more beneficial to the activation of the electric core after the electric core is assembled into a battery.

[0047] It should be noted that in other embodiments of the utility model, the thickness dimension of the partial area of the coating area 11 on the first side 13 along the length direction of the pole piece 10 can be less than the thickness dimension of the second side 14, for example, the area where the thickness dimension of the coating area 11 on the first side 13 is less than the thickness dimension of the second side 14 can be 1 / 2 or 3 / 4 of the whole length of the coating area 11, and the like, which will not be repeated here.

[0048] As shown in the drawing, in some embodiments of the utility model, the thickness dimension of the coating area 11 gradually increases from the first side 13 to the second side 14. Figure 5 So, in addition to the thickness difference of the two sides in the width direction of the electric core being small, the thickness difference of the remaining areas is also small, so that the flatness of the whole electric core can be further improved, which is not only more beneficial to the packaging of the electric core, but also more beneficial to the activation of the electric core after the electric core is assembled into a battery.

[0049] ReferenceFigures 1 to 4 As shown in some embodiments of the utility model, the edge of the first side 13 is provided with a mounting groove 15, and the mounting groove 15 is used for mounting the tab 20. In this embodiment, the mounting groove 15 is opened at the edge of the first side 13, which not only makes it more convenient to mount the tab 20, but also can further reduce the thickness difference of the two sides in the width direction of the battery cell, thereby further improving the flatness of the battery cell as a whole.

[0050] Reference Figure 1 , Figure 2 and Figure 5 As shown in some embodiments of the utility model, the pole piece 10 includes a current collector 100 and two coating layers 200, the two coating layers 200 are respectively coated on the two surfaces in the thickness direction of the current collector 100 to form a coating area 11 with the current collector 100, at least one end of the current collector 100 in the length direction protrudes from the coating layer 200 to form a tab area 12, and the tab area 12 is provided with a mounting groove 15. The current collector 100 can be a metal foil material, for example, when the pole piece 10 is a positive pole piece, the current collector 100 can be an aluminum foil, and when the pole piece 10 is a negative pole piece, the current collector 100 can be a copper foil. Of course, the current collector 100 can also be a composite current collector. When the pole piece 10 is a positive pole piece, the coating layer 200 can include a positive active material, a conductive agent and a binder, etc. These components are mixed in a certain proportion to form a slurry, which is coated on the current collector 100 through a coating process. When the pole piece 10 is a negative pole piece, the coating layer 200 can include a negative active material, a conductive agent and a binder, etc. These components are mixed in a certain proportion to form a slurry, which is coated on the current collector 100 through a coating process. One end or both ends of the current collector 100 in the length direction protrude from the coating layer 200 to form a tab area 12, and the tab area 12 is provided with a mounting groove 15.

[0051] In this embodiment, the two coating layers 200 and the part of the current collector 100 covered by the coating layer 200 together constitute the coating area 11 of the pole piece 10, at least one end of the current collector 100 in the length direction protrudes from the two coating layers 200 to form a tab area 12, and the tab area 12 is provided with a mounting groove 15 for mounting the tab 20. In this way, the structure is simple, the processing is convenient, and the tab 20 is more convenient to mount.

[0052] Reference Figure 3 and Figure 4As shown in the drawings, in some other embodiments of the present application, the middle part of the length direction of the current collector 100 can be exposed to the coating layer 200 at the edge of the first side 13, and a mounting groove 15 is arranged. For example, the two ends of the length direction of the coating layer 200 can extend to the two ends of the length direction of the current collector 100, and the current collector 100 is arranged with the mounting groove 15 at the edge of the first side 13 of the middle part of the length direction, and the other area forms a coating area 11 together with the two coating layers 200. In this embodiment, the tab 20 is mounted at the edge of the first side 13 of the middle part of the length direction of the pole piece 10, and the structure of the pole piece 10 of this embodiment is suitable for the middle tab battery.

[0053] Referring to Figure 5 As shown in the drawings, in some embodiments of the present application, the thickness of the coating layer 200 gradually increases from the first side 13 to the second side 14. That is, the surface of the side away from the two coating layers 200 extends obliquely from the first side 13 to the second side 14 in the direction away from the current collector 100, so that the coating area 11 is approximately isosceles trapezoidal. In this embodiment, by processing the coating layer 200, the thickness of the coating area 11 can be gradually changed, and the thickness of the current collector 100 does not need to be processed. Since the coating layer 200 is soft, the processing is more convenient.

[0054] In some embodiments of the present application, the coating area 11 of the pole piece 10 is processed by rolling. For example, the pole piece 10 can pass between two pressure rollers, and during the process of passing through the two pressure rollers, the distance between the two pressure rollers is gradually adjusted, so that the thickness of the coating area 11 of the pole piece 10 is gradually changed. The operation is simple and convenient, time-saving and labor-saving, and the forming effect of the coating area 11 of the pole piece 10 is better.

[0055] Referring to Figure 7 As shown in the drawings, according to the second aspect of the present application, the battery includes the pole piece 10 and the tab 20 of the first aspect of the present application, and the tab 20 is mounted at the edge of the first side 13 of the pole piece 10. For example, the battery can also include a diaphragm, which can be located between the two pole pieces 10, and the pole pieces 10 and the diaphragm are stacked and can be wound to form a battery.

[0056] The battery uses the pole piece 10 of the first aspect of the present application, and the thickness of the coating area 11 of the pole piece 10 is smaller than the thickness of the second side 14 at least in part of the first side 13, and after forming the battery, even if the thickness of the tab 20 affects the thickness difference of the two sides of the battery in the width direction, the thickness difference is small, thereby further improving the flatness of the battery as a whole, which is not only beneficial to the packaging of the battery, but also beneficial to the activation of the battery after the battery is assembled into a battery.

[0057] It should be noted that since the battery cell can adopt all the technical solutions of the tab 10 of the first aspect embodiment, it at least has all the beneficial effects brought by the technical solutions of the first aspect embodiment. These additional beneficial effects will not be described here in detail.

[0058] It can be understood that other configurations and operations of the battery cell according to the embodiments of the present application are known to those skilled in the art, and will not be described in detail here.

[0059] Referring to Figure 5 and Figure 7 As shown in the drawings, in some embodiments of the present application, the thickness dimension of the coated area 11 on the first side 13 is H1, the thickness dimension of the coated area 11 on the second side 14 is H2, the number of layers of the tab 10 along the thickness direction of the battery cell is n, and the thickness dimension of the tab 20 is T, which satisfies: T = n x (H2-H1), wherein H1 < H2. Taking a certain model of battery cell as an example, the assembly mode of this model of battery cell is winding, the thickness of the tab 20 used by the battery cell is 70 μm, the number of winding layers is 21, the number of layers of the anode tab of the battery cell is 21, and the number of layers of the cathode tab is 20. Without considering the thickness rebound coefficient of the tab 10, the thickness difference of each layer of the tab 10 is approximately 1.7 μm on average.

[0060] In this embodiment, for different models of battery cells, after knowing the thickness of the tab 20 of the battery cell and the number of layers of the tab 10 along the thickness direction of the battery cell, the thickness difference of the coated area 11 of the tab 10 on both sides in the width direction can be calculated by the above formula, and the tab 10 can be precisely machined according to the calculated result. By assembling the machined tab 10 into a battery cell, the thickness difference on both sides in the width direction of the battery cell can be smaller, thereby further improving the overall flatness of the battery cell, which is more conducive to the packaging of the battery cell, and after the battery cell is assembled into a battery, it is more conducive to the activation of the battery cell.

[0061] Referring to Figure 5As shown, in some embodiments of the present application, the thickness difference of the coating area 11 at the second side 14 and the first side 13 satisfies: 0.85 μm≤H2-H1≤6 μm. For example, the thickness difference of the coating area 11 at the second side 14 and the first side 13 can be 0.85 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm or other suitable difference. Generally, the number of layers n of the pole piece 10 of the battery satisfies: 10≤n≤45, and the thickness dimension T of the tab 20 satisfies: 60 μm≤T≤160 μm. In this embodiment, the thickness difference of the coating area 11 at the second side 14 and the first side 13 is between 0.85 μm and 6 μm. Thus, when the number of layers of the pole piece 10 is between 10 and 45 and the thickness dimension of the tab 20 is between 60 μm and 160 μm, the thickness difference of the coating area 11 at the second side 14 and the first side 13 can be avoided to be too small to cause the thickness dimension of the side of the battery provided with the tab 20 to be larger than the thickness dimension of the side of the battery away from the tab 20, thereby affecting the flatness of the battery, and the thickness difference of the coating area 11 at the second side 14 and the first side 13 can be avoided to be too large to cause the thickness dimension of the side of the battery away from the tab 20 to be larger than the thickness dimension of the side of the battery provided with the tab 20, thereby affecting the flatness of the battery.

[0062] The battery according to the third aspect of the present application comprises the battery cell according to the second aspect of the present application.

[0063] The battery adopts the battery cell according to the second aspect of the present application, and the battery cell adopts the pole piece 10 according to the first aspect of the present application. Since the thickness dimension of at least part of the area of the coating area 11 of the pole piece 10 at the first side 13 is smaller than the thickness dimension of the second side 14, and the thickness difference of the two sides of the battery in the width direction is small even due to the influence of the thickness of the tab 20 after the battery cell is formed, the flatness of the battery cell as a whole can be further improved, which is not only beneficial to the packaging of the battery cell, but also beneficial to the activation of the battery cell after the battery cell is assembled into the battery.

[0064] It should be noted that since the battery can adopt all the technical solutions of the pole piece 10 according to the first aspect of the present application and the battery cell according to the second aspect of the present application, at least all the beneficial effects brought by the technical solutions of the first aspect and the second aspect are possessed, and these additional beneficial effects will not be described here in detail.

[0065] It can be understood that other configurations and operations of the battery according to the embodiments of the present application are known to those skilled in the art, and will not be described in detail here.

[0066] The utility model embodiment makes the detailed explanation in combination with the drawing, but the utility model is not limited to the above -mentioned embodiment, still can make various changes in the knowledge range that the person skilled in the art has possesses without departing from the utility model's tenet under the precondition that the knowledge range that the person skilled in the art has possesses.

Claims

1. A pole piece, characterized in that, The polar piece has opposite first and second sides along a width direction of the polar piece, an edge of the first side is configured to mount a tab, and the polar piece is formed with a coating region having a thickness dimension at the first side that is less than a thickness dimension at the second side.

2. The pole piece of claim 1, wherein The coating region has a thickness dimension at all regions of the first side that is less than a thickness dimension at the second side.

3. The pole piece of claim 2, wherein The thickness dimension of the coating region gradually increases from the first side to the second side.

4. The pole piece of claim 1, wherein The edge of the first side is provided with a mounting groove configured to mount the tab.

5. The pole piece of claim 4, wherein, The polar piece includes: a current collector; two coating layers respectively coated on two surfaces of the current collector in a thickness direction to form the coating region with the current collector; wherein at least one end of the current collector in a length direction protrudes from the coating layers to form a tab region provided with the mounting groove, or a middle position of the current collector in the length direction is exposed to the coating layers at the edge of the first side and is provided with the mounting groove.

6. The pole piece of claim 5, wherein The thickness dimension of the coating layer gradually increases from the first side to the second side.

7. An electric cell characterized by It includes: the polar piece according to any one of claims 1 to 6; a tab mounted at the edge of the first side.

8. The electric cell of claim 7, wherein, The coating region has a thickness dimension H1 at the first side, a thickness dimension H2 at the second side, a number of layers n of the polar piece along a thickness direction of the battery cell, and a thickness dimension T of the tab, and satisfies T = n x (H2 - H1), wherein H1 < H2.

9. The electric cell of claim 8, wherein, The thickness difference between the second side and the first side of the coating region satisfies 0.85 μm ≤ H2 - H1 ≤ 6 μm.

10. A battery, characterized by It includes the battery cell according to any one of claims 7 to 9.

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