An electrode core, a method for manufacturing the same, and a battery

Abstract

The application provides a pole core and a preparation method thereof, and a battery. The pole core comprises a plurality of first pole pieces, a plurality of second pole pieces and a plurality of separators. The first pole pieces, the second pole pieces and the separators are stacked in a preset order. The first pole pieces are provided with a first coating area and two first coating adjusting areas. The first coating area is coated along a first direction of the first pole pieces. The two first coating adjusting areas are respectively arranged at two ends of the first coating area along the first direction. The second pole pieces are provided with a second coating area and two second coating adjusting areas. The second coating area is coated along a second direction of the second pole pieces. The two second coating adjusting areas are respectively arranged at two ends of the second coating area along the second direction. The first direction is perpendicular to the second direction. The pole core provided by the application adjusts the coating amount of the four edges of the pole core by arranging the first coating adjusting areas and the second coating adjusting areas, thereby solving the problem of lithium precipitation at the edges of the stacked battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of secondary batteries, and particularly relates to a pole core, a preparation method thereof and a battery. BACKGROUND

[0002] Current lithium ion batteries for electric vehicles and energy storage are mostly square batteries, and current batteries with relatively high energy density are mostly stacked batteries because stacked batteries can fill the gap in the circular arc area of the wound battery. In the process of cycling, the edge of the pole piece is restrained by the aluminum shell during the expansion of the pole piece, and the corresponding pole piece area of the edge of the large surface of the aluminum shell is restrained by a greater force than the central area of the large surface, so lithium precipitation is easily generated, which causes the attenuation of the battery life and the reduction of the safety characteristics. SUMMARY

[0003] In view of the problem that the edge area of the existing stacked battery is prone to lithium precipitation, the application provides a pole core, a preparation method thereof and a battery.

[0004] The technical scheme adopted by the application to solve the above technical problems is as follows:

[0005] In one aspect, the application provides a pole core, comprising a plurality of first pole pieces, a plurality of second pole pieces and a plurality of separators, the first pole pieces, the second pole pieces and the separators are stacked in a predetermined order, the first pole pieces are provided with a first coating area and two first coating adjustment areas, the first coating area is coated along a first direction of the first pole piece, and the two first coating adjustment areas are respectively arranged at both ends of the first coating area along the first direction; the second pole pieces are provided with a second coating area and two second coating adjustment areas, the second coating area is coated along a second direction of the second pole piece, and the two second coating adjustment areas are respectively arranged at both ends of the second coating area along the second direction; the first direction is perpendicular to the second direction.

[0006] The pole core provided by the application has two first coating adjustment areas on the first pole piece, and the first coating adjustment areas are distributed at both ends of the first coating area along the first direction, and has two second coating adjustment areas on the second pole piece, and the second coating adjustment areas are distributed at both ends of the second coating area along the second direction, and the first direction is perpendicular to the second direction, so that the pole core can adjust the amount of coating through the two first coating areas and the two second coating areas to solve the problem of lithium precipitation at the edge of the pole core of the stacked battery.

[0007] Optionally, the pole core further comprises a first tab and a second tab, the first tab is arranged in the second direction of the first pole piece, and the first tab is connected with the first pole piece; the second tab is arranged in the first direction of the second pole piece, and the second tab is connected with the second pole piece.

[0008] Optionally, the first and second tabs are full tabs or multiple die-cut tabs.

[0009] Optionally, the first tab is a negative tab and the second tab is a positive tab.

[0010] Optionally, in the first direction, the width of the first coating adjustment zone is 0.1mm-15mm; in the second direction, the width of the second coating adjustment zone is 0.1mm-15mm.

[0011] Optionally, the thickness of the first coating adjustment zone gradually increases in the direction away from the first coating zone; the thickness of the second coating adjustment zone gradually decreases in the direction away from the second coating zone.

[0012] Optionally, the ratio of the thickness of the first coating adjustment zone at one end away from the first coating zone to the thickness of the first coating zone is 1-1.5; the ratio of the thickness of the second coating adjustment zone at one end away from the second coating zone to the thickness of the second coating zone is 0.01-0.9.

[0013] Optionally, the length of the first tab in the first direction is greater than the length of the second tab in the first direction; the length of the first tab in the second direction is greater than the length of the second tab in the second direction.

[0014] In another aspect, the application also provides a preparation method of the above-mentioned tab core, comprising the following steps: preparing a first tab, a second tab and a separator, when coating the first tab, performing thin coating or thick coating along both ends of the first direction of the first tab to form the first coating adjustment zone; the second direction of the first tab forms a first tab.

[0015] When coating the second tab, perform thin coating or thick coating along both ends of the second direction of the second tab to form the second coating adjustment zone; the first direction of the second tab forms a second tab.

[0016] Stacking, stacking the first tab, the separator and the second tab to prepare the tab core, wherein the first tab is in the second direction of the tab core and the second tab is in the first direction of the tab core.

[0017] In another aspect, the application also provides a battery comprising the above-mentioned tab core. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the tab core provided by an embodiment of the application;

[0019] Figure 2is a top view of the pole core provided by an embodiment of the present application;

[0020] Figure 3 is a front view of the pole core provided by an embodiment of the present application;

[0021] Figure 4 is a side view of the pole core provided by an embodiment of the present application.

[0022] The reference signs in the drawings of the specification are as follows:

[0023] 1, first pole piece; 11, first coating area; 12, first coating adjustment area; 13, first pole lug;

[0024] 2, second pole piece; 21, second coating area; 22, second coating adjustment area; 23, second pole lug;

[0025] 3, diaphragm. DETAILED DESCRIPTION

[0026] In order to make the technical problems solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0027] In the description of the present application, it should be understood that the terms "front", "back", "vertical", "horizontal", "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or position of the pole core. Only for the convenience of describing the present application and simplifying the description, it is not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0028] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connection", "lap joint" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] Referring to Figures 1-4As shown, an embodiment of the present application provides a pole core, which comprises a plurality of first pole pieces 1, a plurality of second pole pieces 2 and a plurality of separators 3, the first pole pieces 1, the second pole pieces 2 and the separators 3 are stacked in a preset order, the first pole piece 1 is provided with a first coating area 11 and two first coating adjustment areas 12, the first coating area 11 is coated along a first direction of the first pole piece 1, and the two first coating adjustment areas 12 are respectively arranged at both ends of the first coating area 11 along the first direction. The second pole piece 2 is provided with a second coating area 21 and two second coating adjustment areas 22, the second coating area 21 is coated along a second direction of the second pole piece 2, and the two second coating adjustment areas 22 are respectively arranged at both ends of the second coating area 21 along the second direction. The first direction is perpendicular to the second direction.

[0030] The pole core provided by the embodiment adjusts the amount of coating by the two first coating areas 11 and the two second coating areas 21, adjusts the thickness of the local pole core, thereby reducing the restraint force between the edge of the pole core and the edge of the shell, so as to solve the problem of lithium precipitation at the edge of the pole core of the laminated battery.

[0031] As shown in the drawings, Figure 1 In an embodiment, the pole core further comprises a first tab 13 and a second tab 23, the first tab 13 is arranged in the second direction of the first pole piece 1, and the first tab 13 is connected with the first pole piece 1. The second tab 23 is arranged in the first direction of the second pole piece 2, and the second tab 23 is connected with the second pole piece 2. When the first pole piece 1 is coated, an uncoated area is left in the second direction to form the first tab 13. When the second pole piece 2 is coated, an uncoated area is left in the first direction to form the second tab 23. The first tab 13 is arranged in the second direction, and the second tab 23 is arranged in the first direction, so that the first tab 13 and the second tab 23 are led out from the two adjacent edges of the pole core.

[0032] As shown in the drawings, Figure 2 In an embodiment, the first tab 13 and the second tab 23 are full tabs or a plurality of die-cut tabs. Specifically, the first tab 13 and the second tab 23 can be cut into different shapes according to actual conditions.

[0033] As shown in the drawings, Figures 3-4 In an embodiment, the first pole piece 1 is a negative pole piece, and the second pole piece 2 is a positive pole piece.

[0034] like Figures 1-4 As shown, in one embodiment, the width of the first coating adjustment area 12 is 0.1 mm to 15 mm in the first direction. In the second direction, the width of the second coating adjustment area 22 is 0.1 mm to 15 mm.

[0035] like Figures 1-4 As shown, in one embodiment, the thickness of the first coating adjustment region 12 gradually increases in the direction away from the first coating region 11. The thickness of the second coating adjustment region 22 gradually decreases in the direction away from the second coating region 21. The first electrode 1 is a negative electrode, and the second electrode 2 is a positive electrode. By reducing the amount of coating in the second coating adjustment region 22, the thickness of the second coating adjustment region 22 is reduced, thereby reducing the binding force and avoiding lithium plating. By increasing the amount of coating in the first coating adjustment region 12, the capacity ratio of the local negative electrode to the positive electrode is increased, thereby avoiding the problem of edge lithium plating.

[0036] It should be noted that, for other requirements, the coating thickness of the positive electrode can gradually increase from the center to the edge, and the coating thickness of the negative electrode can gradually decrease from the center to the edge. In other words, the thickness of the first coating adjustment zone 12 and the second coating adjustment zone 22 can be adjusted as needed.

[0037] like Figures 1-4 As shown, in one embodiment, the thickness of the end of the first coating adjustment zone 12 away from the first coating zone 11 is 1 to 1.5 times the thickness of the first coating zone 11. The thickness of the end of the second coating adjustment zone 22 away from the second coating zone 21 is 0.01 to 0.9 times the thickness of the second coating zone 21.

[0038] like Figures 2-4 As shown, in one embodiment, the length of the first electrode 1 in the first direction is greater than the length of the second electrode 2 in the first direction. The length of the first electrode 1 in the second direction is greater than the length of the second electrode 2 in the second direction, so that the first electrode can fully receive the lithium ions provided by the second electrode, avoiding lithium plating.

[0039] An embodiment of the present invention also provides a method for preparing an electrode core as described in any of the preceding embodiments, comprising the following steps:

[0040] A first electrode 1, a second electrode 2, and a diaphragm 3 are prepared. During coating on the first electrode 1, the coating is thinned or thickened at both ends along a first direction on the first electrode 1 to form the first coating adjustment area 12. The uncoated area along the second direction of the first electrode 1 forms the first tab 13.

[0041] When coating on the second tab 2, thin coating or thick coating is performed along both ends of the second direction on the second tab 2 to form the second coating adjustment area 22. The first direction non-coating area of the second tab 2 forms a second tab 23.

[0042] The first tab 1, the separator 3 and the second tab 2 are laminated to prepare the pole core, wherein the first tab 13 is in the second direction of the pole core and the second tab 23 is in the first direction of the pole core.

[0043] An embodiment of the present application further provides a battery comprising the pole core according to any one of the above embodiments.

[0044] The above merely describes preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pole core, characterized by, The electrode core comprises a plurality of first pole pieces, a plurality of second pole pieces and a plurality of separators, the first pole pieces, the second pole pieces and the separators are stacked in a preset order, the first pole piece is provided with a first coating area and two first coating adjustment areas, the first coating area is coated along a first direction of the first pole piece, and the two first coating adjustment areas are respectively arranged at two ends of the first coating area along the first direction; the second pole piece is provided with a second coating area and two second coating adjustment areas, the second coating area is coated along a second direction of the second pole piece, and the two second coating adjustment areas are respectively arranged at two ends of the second coating area along the second direction; the first direction is perpendicular to the second direction; The first pole piece is a negative pole piece, the second pole piece is a positive pole piece, the thickness of the first coating adjustment area gradually increases in a direction away from the first coating area; the thickness of the second coating adjustment area gradually decreases in a direction away from the second coating area; The electrode core further comprises a first tab and a second tab, the first tab and the second tab are full tabs or a plurality of die-cut tabs; the first tab is connected with the first pole piece, and the second tab is connected with the second pole piece.

2. The pole core of claim 1, wherein The first tab is arranged in the second direction of the first pole piece, and the second tab is arranged in the first direction of the second pole piece.

3. The pole core of claim 1, wherein In the first direction, the width of the first coating adjustment area is 0.1mm-15mm; in the second direction, the width of the second coating adjustment area is 0.1mm-15mm.

4. The pole core of claim 1, wherein The ratio of the thickness of one end of the first coating adjustment area away from the first coating area to the thickness of the first coating area is greater than 1 and less than or equal to 1.5; the ratio of the thickness of one end of the second coating adjustment area away from the second coating area to the thickness of the second coating area is 0.01-0.

9.

5. The pole core of claim 1, wherein The length of the first pole piece in the first direction is greater than the length of the second pole piece in the first direction; the length of the first pole piece in the second direction is greater than the length of the second pole piece in the second direction.

6. A method of producing the electrode as claimed in any one of claims 1 to 5, characterized by, The method comprises the following steps: Preparation of a first pole piece, a second pole piece and a separator, when coating on the first pole piece, thickening coating is performed along both ends of the first direction of the first pole piece to form the first coating adjustment area; the second direction of the first pole piece forms a first tab; When coating on the second pole piece, thinning coating is performed along both ends of the second direction of the second pole piece to form the second coating adjustment area; The first direction of the second pole piece forms a second tab; Stacking, stacking the first pole piece, the separator and the second pole piece to prepare the electrode core, wherein the first tab is in the second direction of the electrode core, and the second tab is in the first direction of the electrode core.

7. A battery, characterized by The electrode core comprises any one of claims 1-5.

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