Lithium ion battery cell
By setting grooves on the current collector of the lithium-ion battery electrode sheet and welding the electrode ears, the problems of poor battery flatness and small welding area caused by uneven thickness of the electrode ears are solved, and higher energy density and structural balance are achieved.
Patent Information
- Application Number
- CN202421574141.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-04
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-07-04
AI Technical Summary
The thickness of the electrode on the electrodes of the existing lithium-ion battery is uneven after welding, resulting in poor battery flatness and small welding area, which affects the current conduction ability and reduces the energy density.
A groove is provided on the current collector, and the extreme ear is welded in the groove, the depth of the groove is equal to half of the thickness of the extreme ear, and the extreme ear is welded on multiple sides to increase the welding area and avoid the problem of dummy welding.
The problem of convexity of the pole ear area is solved, the flatness and energy density of the battery cell are improved, the problem of dummy welding is avoided, and the structural stress balance of the battery is enhanced.
Smart Images
Figure CN222775330U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of batteries, and in particular relates to a lithium-ion battery core. Background Art
[0002] As electronic devices become increasingly intelligent and miniaturized, the lithium-ion batteries used are also required to have a smaller volume and flatness while ensuring good energy density. In order to improve the distribution of current density on the lithium battery electrode sheet, the tab is often welded to the middle of the electrode sheet. However, due to the large thickness of the tab, the thickness will become even greater after welding on the current collector, and the outer surface of the tab will exceed the surface of the active material coating in the adjacent area. Especially after the tape is pasted, the thickness of the entire core is uneven, which affects the flatness of the battery. Figure 5 As shown, in the prior art, the tab 23 is welded to the blank area 24 on one side of the electrode sheet 21. The thickness of the tab exceeds the thickness of the active material layer 22 on one side, causing the tab 23 to bulge outward, resulting in uneven thickness across the entire cell. Furthermore, the tab is only welded to the current collector on one side, leading to cold welds. Furthermore, the small weld area affects current conduction and reduces the battery's energy density. Utility Model Content
[0003] In response to the above problems, the utility model proposes a lithium-ion battery cell, in which a groove is provided on the current collector, and the tab is welded inside the groove. The depth of the groove is designed to be half of the thickness of the tab, which solves the problem of the tab bulging outward. At the same time, the tab and the groove are welded on multiple sides, which greatly increases the welding area, avoids the occurrence of cold welding problems, and improves the energy density of the battery.
[0004] The technical solutions adopted in this utility model are as follows:
[0005] A lithium-ion battery cell comprises a first pole piece, a diaphragm, a second pole piece, a first pole tab and a second pole tab, the diaphragm being arranged between the first pole piece and the second pole piece, the first pole piece, the diaphragm and the second pole piece being wound to form the battery cell, the first pole piece comprising a first current collector having a first groove and an active material coating applied to an area outside the first groove, the second pole piece comprising a second current collector having a second groove and an active material coating applied to an area outside the second groove, the first pole tab being welded in the first groove, and the second pole tab being welded in the second groove, the depth of the first groove being equal to half the thickness of the first pole tab and less than the thickness of the active material coating on a single side of the first pole piece, the depth of the second groove being equal to half the thickness of the second pole tab and less than the thickness of the active material coating on a single side of the second pole piece.
[0006] A groove is set on the current collector, and the tab is welded in the groove. The depth of the groove is equal to half the thickness of the tab and is less than the thickness of the active material coating on one side of the pole piece. With this arrangement, the thickness of the tab is dispersed on both sides of the opposite sides of the pole piece, and the surfaces on both sides of the tab do not exceed the surface of the active material coating, making the surface of the entire battery cell smoother and reducing the volume of the battery cell. At the same time, the structural optimization brings about balanced force and the battery cell is not easily damaged.
[0007] Furthermore, the thickness of the first electrode tab is greater than the thickness of the active material coating on one side of the first electrode piece, and the thickness of the second electrode tab is greater than the thickness of the active material coating on one side of the second electrode piece.
[0008] The thickness of the tab is greater than the thickness of the active material coating on one side of the electrode. The thickness of the tab is dispersed on both sides of the electrode, which improves the flatness of the battery cell.
[0009] Furthermore, the first groove includes a first welding surface located on both sides of the groove and a second welding surface located on the bottom of the groove, and the second groove includes a third welding surface located on both sides of the groove and a fourth welding surface located on the bottom of the groove.
[0010] Arranging multiple welding surfaces in the groove increases the welding area and is beneficial to the collection of current.
[0011] Furthermore, the first tab includes a fifth welding surface located on both sides of the tab and a sixth welding surface located on the front of the tab, and the second tab includes a seventh welding surface located on both sides of the tab and an eighth welding surface located on the front of the tab.
[0012] A plurality of welding surfaces corresponding to the grooves are provided on the tab, so that the welding connection of the tab is more firm and the problem of cold welding is avoided.
[0013] Furthermore, the fifth welding surface, the sixth welding surface, the seventh welding surface and the eighth welding surface are all provided with curved welding points. Furthermore, the curved welding points are U-shaped, S-shaped or C-shaped.
[0014] Curved welding points are provided on multiple welding surfaces, which increases the welding area and facilitates current conduction.
[0015] Furthermore, the first welding surface is welded to the fifth welding surface, the second welding surface is welded to the sixth welding surface, the third welding surface is welded to the seventh welding surface, and the fourth welding surface is welded to the eighth welding surface.
[0016] Furthermore, the welding is ultrasonic welding, resistance welding or laser welding.
[0017] Furthermore, a first insulating tape is attached to both sides of the first tab corresponding to the first current collector, and a second insulating tape is attached to both sides of the second tab corresponding to the second current collector.
[0018] Furthermore, the first electrode is a positive electrode or a negative electrode, and the second electrode is a negative electrode or a positive electrode.
[0019] The beneficial effects of the present invention are as follows: grooves are provided on the first and second current collectors, and the first and second pole tabs are welded in the grooves. The depth of the grooves is equal to half the thickness of the pole tabs and is less than the thickness of the active material coating on one side of the pole piece. Since the thickness of the pole tabs is dispersed on both sides of the opposite sides of the pole piece, the surfaces on both sides of the pole tabs do not exceed the surface of the active material coating, so that the surface of the entire battery cell is smoother and the volume of the battery cell is reduced. At the same time, the structural optimization brings about force balance, and the battery cell is not easily damaged; the first groove is provided with a first welding surface and a second welding surface, the second groove is provided with a third welding surface and a fourth welding surface, the first pole tab is provided with a fifth welding surface and a sixth welding surface, and the second pole tab is provided with a seventh welding surface and an eighth welding surface. The first welding surface is welded to the fifth welding surface, the second welding surface is welded to the sixth welding surface, the third welding surface is welded to the seventh welding surface, and the fourth welding surface is welded to the eighth welding surface. The multiple welding surfaces increase the welding area, which is conducive to the collection of current, and the welding connection of the pole tabs is more firm, avoiding the problem of cold welding. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only 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.
[0021] Figure 1 The utility model is a structural schematic diagram of a lithium-ion battery cell.
[0022] Figure 2 This is a structural schematic diagram of a first pole piece and a second pole piece of a lithium-ion battery cell of the present invention.
[0023] Figure 3 This is a schematic structural diagram of a first electrode tab and a second electrode tab of a lithium-ion battery cell of the present invention.
[0024] Figure 4 The utility model is a schematic diagram of the tab welding structure of a lithium-ion battery cell.
[0025] Figure 5It is a schematic diagram of the prior art tab welding structure.
[0026] Reference numerals:
[0027] 1. First pole piece; 2. Second pole piece; 3. Diaphragm; 4. First pole tab; 5. First groove; 6. Insulating tape; 7. Second pole tab; 8. Second groove; 9. Fifth welding surface; 9', Seventh welding surface; 10. Sixth welding surface; 10', Eighth welding surface; 11. Welding point; 12. First welding surface; 12', Third welding surface; 13. Second welding surface; 13', Fourth welding surface; 14. Active material coating. DETAILED DESCRIPTION
[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0029] like Figure 1-2 As shown in Figure 4, the present invention provides a lithium-ion battery cell, comprising a first pole piece 1, a separator 3, a second pole piece 2, a first pole tab 4, and a second pole tab 7. The separator 3 is disposed between the first pole piece 1 and the second pole piece 2. The first pole piece 1, the separator 3, and the second pole piece 2 are wound to form the cell. The above structures are all conventional existing structures and will not be described in detail here. The first pole piece 1 includes a first current collector having a first groove 5 and an active material coating 14 coated on the area outside the first groove 5. The second pole piece 2 includes a second current collector having a second groove 8 and an active material coating 14 coated on the area outside the second groove 8. The first groove and the second groove are rectangular grooves. The active material coating is a coating of active materials for the positive and negative electrodes of the battery. For example, the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, etc., and the negative electrode active material can be artificial graphite, etc., all of which are mature technologies in this field. The first pole tab 4 is welded in the first groove 5, and the second pole tab 7 is welded in the second groove 8. The depth of the first groove 5 is equal to half the thickness of the first pole tab 4 and is less than the thickness of the single-sided active material coating 14 of the first pole piece 1. The depth of the second groove 8 is equal to half the thickness of the second pole tab 7 and is less than the thickness of the single-sided active material coating 14 of the second pole piece 2.
[0030] It should be noted that the first groove and the second groove are arranged in the blank area of the first pole piece and the second pole piece, and no active material coating is provided in the blank area. The grooves are located at 1 / 4-3 / 4 of the length direction of the pole piece.
[0031] The thickness of the first electrode tab 4 is greater than the thickness of the active material coating on one side of the first electrode piece 1, and the thickness of the second electrode tab 7 is greater than the thickness of the active material coating on one side of the second electrode piece 2. The thickness of the electrode tab is related to the current conductivity, and using a thicker electrode tab is conducive to current collection.
[0032] like Figure 4 As shown, the first groove 5 includes first welding surfaces 12 located on both sides of the groove and a second welding surface 13 located on the bottom of the groove. The second groove 8 includes third welding surfaces 12' located on both sides of the groove and a fourth welding surface 13' located on the bottom of the groove. The rectangular groove wraps around the tab, which can not only disperse the thickness of the tab, but also increase the welding area. The groove also plays a role in positioning the tab during welding.
[0033] like Figure 3 As shown, the first tab 4 includes fifth welding surfaces 9 located on both sides of the tab and a sixth welding surface 10 located on the front of the tab. The second tab 7 includes a seventh welding surface 9' located on both sides of the tab and an eighth welding surface 10' located on the front of the tab. The fifth welding surface 9, the sixth welding surface 10, the seventh welding surface 9' and the eighth welding surface 10' are all provided with curved welding points 11, which increase the welding area.
[0034] Optionally, the curved welding point 11 is U-shaped, S-shaped or C-shaped.
[0035] Optionally, the first welding surface 12 is welded to the fifth welding surface 9 , the second welding surface 13 is welded to the sixth welding surface 10 , the third welding surface 12 ′ is welded to the seventh welding surface 9 ′, and the fourth welding surface 13 ′ is welded to the eighth welding surface 10 ′.
[0036] Optionally, the welding is ultrasonic welding, resistance welding or laser welding.
[0037] Optionally, insulating tape 6 is attached to both sides of the first tab 4 corresponding to the first current collector, and insulating tape 6 is attached to both sides of the second tab 7 corresponding to the second current collector. The insulating tape can protect the tab structure and prevent burrs from damaging the battery cell. At the same time, the insulating tape fills the thickness difference between the tab and the active material coating, improving the flatness of the battery cell. The insulating tape can fully or partially cover the blank area.
[0038] Optionally, the first electrode 1 is a positive electrode or a negative electrode, and the second electrode 2 is a negative electrode or a positive electrode.
[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A lithium-ion battery cell, comprising a first pole piece (1), a diaphragm (3), a second pole piece (2), a first pole ear (4) and a second pole ear (7), wherein the diaphragm (3) is arranged between the first pole piece (1) and the second pole piece (2), and the first pole piece (1), the diaphragm (3) and the second pole piece (2) are wound to form the battery cell, characterized in that: The first pole piece (1) comprises a first current collector provided with a first groove (5) and an active material coating (14) coated on an area outside the first groove (5); the second pole piece (2) comprises a second current collector provided with a second groove (8) and an active material coating (14) coated on an area outside the second groove (8); the first pole lug (4) is welded in the first groove (5); the second pole lug (7) is welded in the second groove (8); the depth of the first groove (5) is equal to half the thickness of the first pole lug (4) and is less than the thickness of the active material coating (14) on a single side of the first pole piece (1); the depth of the second groove (8) is equal to half the thickness of the second pole lug (7) and is less than the thickness of the active material coating (14) on a single side of the second pole piece (2).
2. The lithium-ion battery cell according to claim 1, characterized in that: The thickness of the first pole tab (4) is greater than the thickness of the active material coating on one side of the first pole piece (1), and the thickness of the second pole tab (7) is greater than the thickness of the active material coating on one side of the second pole piece (2).
3. The lithium-ion battery cell according to claim 2, characterized in that: The first groove (5) comprises a first welding surface (12) located on both sides of the groove and a second welding surface (13) located on the bottom of the groove, and the second groove (8) comprises a third welding surface (12') located on both sides of the groove and a fourth welding surface (13') located on the bottom of the groove.
4. The lithium-ion battery cell according to claim 3, characterized in that: The first pole tab (4) comprises a fifth welding surface (9) located on both sides of the pole tab and a sixth welding surface (10) located on the front side of the pole tab, and the second pole tab (7) comprises a seventh welding surface (9') located on both sides of the pole tab and an eighth welding surface (10') located on the front side of the pole tab.
5. The lithium-ion battery cell according to claim 4, characterized in that: The fifth welding surface (9), the sixth welding surface (10), the seventh welding surface (9') and the eighth welding surface (10') are all provided with curved welding points (11).
6. The lithium-ion battery cell according to claim 5, characterized in that: The curved welding point (11) is U-shaped, S-shaped or C-shaped.
7. The lithium-ion battery cell according to claim 4, characterized in that: The first welding surface (12) is welded to the fifth welding surface (9), the second welding surface (13) is welded to the sixth welding surface (10), the third welding surface (12') is welded to the seventh welding surface (9'), and the fourth welding surface (13') is welded to the eighth welding surface (10').
8. The lithium-ion battery cell according to claim 1, characterized in that: The welding is ultrasonic welding, resistance welding or laser welding.
9. The lithium-ion battery cell according to claim 1, characterized in that: Insulating tape (6) is adhered to two sides of the first electrode tab (4) corresponding to the first current collector, and insulating tape (6) is adhered to two sides of the second electrode tab (7) corresponding to the second current collector.
10. The lithium-ion battery cell according to any one of claims 1 to 9, characterized in that: The first pole piece (1) is a positive pole piece or a negative pole piece, and the second pole piece (2) is a negative pole piece or a positive pole piece.