Electrode plate and battery cell
The electrode plate design with alternating lithium strips on the surface and side end surfaces addresses uneven lithium deposition, enhancing lithium replenishment and energy density in silicon-doped batteries, and mitigates safety risks.
Patent Information
- Application Number
- CN202323318963.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2033-12-06
AI Technical Summary
The discontinuity of lithium replenishment in silicon-doped batteries leads to uneven local lithium deposition and insufficient lithium replenishment, hindering the effective improvement of energy density.
An electrode plate design with alternating bright and dark areas on its surface and side end surfaces, supplemented by interstitial lithium strips, ensuring uniform lithium distribution and preventing edge lithium burrs.
Enhances lithium replenishment, improving the initial efficiency and energy density of silicon-doped batteries while preventing safety hazards from edge lithium burrs.
Smart Images
Figure CN222168429U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of battery technology, and in particular to an electrode plate and a battery cell. Background Art
[0002] Silicon material has a high theoretical specific capacity and is an ideal material to replace graphite negative electrodes and improve the energy density of lithium-ion batteries. However, silicon material also has an obvious shortcoming in practical applications, that is, the coulomb efficiency of the first charge and discharge cycle is lower than that of the graphite negative electrode (generally, the first efficiency of silicon negative electrode is between 69%-85%, and the first efficiency of graphite negative electrode is between 90%-94%). An effective method is to pre-replenish lithium to the pole piece to replenish the irreversible capacity consumed in the first cycle, improve the first efficiency of silicon-doped batteries, and then improve the energy density of the battery.
[0003] However, in the prior art, the discontinuity of lithium replenishment leads to differences in local area dynamics, resulting in uneven local lithium deposition and insufficient lithium replenishment, making it difficult to effectively improve the energy density of the battery. Utility Model Content
[0004] In view of this, in order to solve the technical problem in the prior art that the amount of lithium replenishment is insufficient and the energy density of the battery is low, the present application provides an electrode plate, which further supplements the amount of lithium replenishment of the electrode plate and improves the energy density of the battery by covering the side end surface of the electrode plate with a gap lithium strip.
[0005] In order to achieve the above objectives, this application provides the following technical solutions:
[0006] An electrode plate, comprising:
[0007] A first pole piece, the first pole piece having a first surface and a second surface arranged opposite to each other, a first active material layer being arranged on the first surface and the second surface respectively, and the first pole piece having a first direction and a second direction;
[0008] Bright areas and dark areas are alternately arranged on the first active material layer along the first direction of the first pole piece, the bright areas extend to the edge of the first pole piece along the second direction of the first pole piece, and the dark areas extend to the edge of the first pole piece along the second direction of the first pole piece; at least part of the bright areas extend to the side end surface of the first pole piece.
[0009] Optionally, at least part of the dark area extends to a side end surface of the first pole piece;
[0010] The bright area and the dark area extending to the side end surface of the first pole piece are alternately arranged on the side end surface of the first pole piece.
[0011] Optionally, the width of the bright area ranges from 100 to 2000 μm, and the width of the dark area ranges from 100 to 2000 μm.
[0012] The electrode plate provided in the present application is not only covered with interstitial lithium strips on the first surface and the second surface of the electrode plate, but also covered with interstitial lithium strips on the side end surfaces of the electrode plate, further replenishing lithium to the surface of the electrode plate that has not been replenished with lithium, thereby increasing the amount of lithium replenishment of the electrode plate, thereby improving the initial efficiency of the silicon-doped battery and further improving the energy density of the battery.
[0013] The present application also provides a battery cell, comprising the electrode plate and a second plate, wherein the second plate has a third surface and a fourth surface arranged opposite to each other, and a second active material layer is respectively arranged on the third surface and the fourth surface.
[0014] Optionally, the second pole piece has a first direction and a second direction corresponding to the first pole piece, and the second pole piece, the diaphragm and the first pole piece are wound together to form the battery cell, and the head and the tail of the second pole piece in the first direction are respectively affixed with adhesive tape, and the adhesive tape covers the surface of the second active material layer on the side of the second pole piece opposite to the first pole piece.
[0015] Optionally, a size of the adhesive tape in the first direction is larger than a size of the first pole piece in the first direction.
[0016] Optionally, a first color zone is formed on a surface of the first pole piece opposite to the adhesive tape, and a second color zone is formed on a surface of the first pole piece opposite to an area of the second pole piece not affixed with the adhesive tape.
[0017] Optionally, the RGB value range of the first color area is (112±45, 104±45, 104±45), and / or,
[0018] The RGB value range of the second color area is (145±50, 135±50, 96±50).
[0019] Optionally, the first color region forms a first color bright region and a first color dark region that alternate between light and dark in a first direction of the first pole piece.
[0020] Optionally, the number of the first color bright areas in the first color area is Y, the length of the first color area is X μm, and the relationship between X and Y satisfies: X / 2000≤Y<X / 100.
[0021] Optionally, there is a height difference between surfaces of the first bright color area and the first dark color area in the first color area, and the height difference is 0.02-30 μm.
[0022] The first pole piece of the battery cell is supplemented with gap lithium strips on its two side end faces, thereby increasing the amount of lithium supplemented in the pole piece. Therefore, when the battery cell is used in a lithium battery, the battery's first efficiency, energy density and cycle performance can be improved. Compared with the situation in the prior art where the gap lithium strip is easily fallen off at the edge of the side end face of the pole piece, the side end face of the pole piece can effectively eliminate the edge lithium burrs in the process of supplementing the gap lithium strip, thereby avoiding the safety hazard of the battery cell caused by the falling of lithium burrs. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.
[0024] Figure 1 It is a schematic diagram of the first active material layer on the upper surface and the lower surface of the first electrode sheet in the prior art being fully replenished with lithium through the interstitial lithium strip;
[0025] Figure 2 It is a physical schematic diagram of the interstitial lithium strip covering the upper surface of the first pole piece in the prior art;
[0026] Figure 3 A schematic diagram of a long side end surface of the first pole piece in the present application;
[0027] Figure 4 This is a schematic diagram of the alignment of the second pole piece with adhesive tape on the head, the diaphragm and the first pole piece in this application;
[0028] Figure 5 It is a characteristic schematic diagram of the junction of the first color bright area and the first color dark area in the first color area.
[0029] exist Figure 1-Figure 5 middle:
[0030] 1. First electrode; 11. Copper foil; 12. First active material layer; 2. Second electrode; 21. Aluminum foil; 22. Second active material layer; 23. Adhesive tape; 3. Diaphragm; 4. Gap lithium strip; 41. Lithium strip; 42. Edge lithium burrs; 51. Bright area; 52. Dark area; 61. First color area; 611. First color bright area; 612. First color dark area; 62. Second color area. DETAILED DESCRIPTION
[0031] The present application provides an electrode plate, which further supplements the lithium replenishment of the electrode plate by covering the side end surface of the electrode plate with a gap lithium strip.
[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0033] like Figure 1-Figure 5 As shown, the embodiment of the present application provides an electrode plate, comprising:
[0034] A first electrode 1, the first electrode has a first surface and a second surface arranged opposite to each other, a first active material layer is arranged on the first surface and the second surface respectively, and the first electrode has a first direction and a second direction; a bright area and a dark area are alternately arranged on the first active material layer along the first direction of the first electrode, the bright area extends to the edge of the first electrode along the second direction of the first electrode, and the dark area extends to the edge of the first electrode along the second direction of the first electrode; at least part of the bright area extends to the side end surface of the first electrode.
[0035] The electrode plate provided in the present application is not only covered with interstitial lithium strips on the first surface and the second surface of the first electrode plate, but also covered with interstitial lithium strips on the side end surface of the first electrode plate, further replenishing lithium to the surface of the first electrode plate that has not been replenished with lithium, thereby increasing the amount of lithium replenishment of the first electrode plate, thereby improving the initial efficiency of the silicon-doped battery, and further improving the energy density of the battery.
[0036] In this embodiment, the first electrode 1 is a negative electrode. Figure 3 As shown, the first electrode sheet 1 includes a copper foil 11 in the middle, and two first active material layers 12 respectively arranged on the upper surface (i.e., the first surface) and the lower surface (i.e., the second surface) of the copper foil 11, and the side end surface of the first electrode sheet 1 in the first direction is the long side end surface;
[0037] like Figure 1 As shown in the figure, the X-axis direction is the first direction of the first pole piece 1, and the Y-axis direction is the second direction of the first pole piece 1. In the prior art, the gap lithium strip 4 completely covers the second direction of the first pole piece 1 and is wider than the first pole piece 1; Figure 2 As shown, the gap lithium strip 4 includes a plurality of lithium strips 41 distributed along the first direction thereof, and the lithium strips 41 extend along the second direction of the gap lithium strip 4, and there is a gap between two adjacent lithium strips 41. Figure 2 It can be seen that the lithium strips 41 and the gaps appear alternately along the first direction of the gap lithium strips 4, the lithium strips 41 form a lithium supplement area on the first pole piece 1, and the gaps between the lithium strips 41 are non-lithium supplement areas on the first pole piece 1;
[0038] The first active material layer 12 on the upper surface and the first active material layer 12 on the lower surface are both connected with a gap lithium strip 4, and the gap lithium strip 4 completely covers the first active material layer 12 on the upper surface and the lower surface. In order to achieve this requirement, it is necessary to make the width of the gap lithium strip 4 greater than the width of the first pole piece 1, and the gap lithium strip 4 exceeds the portion of the second direction edge of the first pole piece 1. In the present application, a trimming process can be used, such as brushing the edge lithium burrs 42 extending to the outside of the second direction edge of the first pole piece 1 toward the long side end face by a brush, and the edge lithium burrs 42 are bent and tightly connected to the long side end face of the first pole piece 1. In this way, on the one hand, the side end face of the first pole piece can be supplemented with lithium; on the other hand, the remaining part of the edge lithium burrs 42 falls off during the brushing process, thereby avoiding the edge lithium burrs 42 from falling off and being free in the battery cell in the subsequent process to pierce the diaphragm 3 and cause the first pole piece 1 to contact the second pole piece 2. On the other hand, it can also avoid the edge lithium burrs 42 from contacting the aluminum-plastic film to cause a short circuit.
[0039] Of course, the trimming process of bending the edge lithium burr 42 and fitting it to the end surface of the long side can also be achieved by other methods.
[0040] like Figure 3 As shown, the lithium strip 41 on the long side end face is embedded in the long side end face after the injection cycle and forms a bright area 51 and a dark area 52 alternating between light and dark on the long side end face along the first direction of the first pole piece 1, that is, the bright area 51 and the dark area 52 formed by lithium supplementation and non-lithium supplementation. The alternating bright area 51 and the dark area 52 can be observed under a 3D microscope, and whether the alternating bright area 51 and the dark area 52 are observed can be used to characterize whether the gap lithium sheet of the first pole piece 1 has been trimmed to process the edge lithium burrs 42;
[0041] Furthermore, since the bright areas 51 and dark areas 52 on the end faces of the long sides are formed by bending down the lithium strips 41 of the interstitial lithium strips 4 on the surface of the first active material layer 12, the lithium strips 41 on the surface of the first active material layer 12 of the first electrode sheet 1 also form alternating bright and dark bright areas 51 and dark areas 52 along the first direction of the first electrode sheet 1, and the bright areas 51 and dark areas 52 on the surface of the first active material layer 12 of the first electrode sheet 1 basically correspond one to one to the bright areas 51 and dark areas 52 on the end faces of the long sides.
[0042] The features of the long side end faces are further observed and measured. For example, the slicing method and 3D electron microscope are used to characterize the features of the long side end faces of the first electrode 1 that has been supplemented with lithium by the interstitial lithium strip 4 and has undergone the trimming process. The width of the bright area 51 ranges from 100 to 2000 μm, and the width of the dark area 52 ranges from 100 to 2000 μm.
[0043] like Figure 4 and 5As shown, the present application also provides a battery cell, comprising the above-mentioned electrode plate, and further comprising a second plate 2. In this embodiment, the second plate 2 is a positive plate, and the positive plate comprises an aluminum foil 21, and two second active material layers 22 respectively arranged on the upper surface (i.e., the third surface) and the lower surface (i.e., the fourth surface) of the aluminum foil 21;
[0044] Furthermore, the second pole piece 2 can be wound together with the diaphragm 3 and the first pole piece 1 to form a battery cell. The second pole piece 2 has a first direction and a second direction corresponding to the first pole piece 1. The head and tail of the second pole piece 2 in the first direction are respectively affixed with adhesive tape 23, and the adhesive tape 23 covers the surface of the second active material layer 22 on the side of the second pole piece 2 opposite to the first pole piece 1. Affixing the adhesive tape 23 on the head and tail of the second pole piece 2 in the first direction has the following function: preventing the lithium layer on the head and tail of the first direction of the first pole piece 1 from piercing the diaphragm 3 and thereby contacting the aluminum foil 21 of the second pole piece 2.
[0045] The battery cell provided in the present application is used for lithium batteries, which can improve the battery's initial efficiency, energy density and cycle performance, and can effectively eliminate the safety hazards caused by edge lithium burrs 42.
[0046] like Figure 4 As shown, the adhesive tape 23 not only covers the lower surface of the second active material layer 22 , but also covers the side end surface of the second active material layer 22 , and extends to the surface of the aluminum foil 21 .
[0047] Preferably, the width of the adhesive tape 23 is greater than the width of the first pole piece 1 , thereby preventing the burrs of the cut aluminum foil 21 from penetrating through the diaphragm 3 and contacting the first pole piece 1 to cause a short circuit.
[0048] like Figure 3 and 4 As shown, after the battery including the cell is fully charged, the surface of the first pole piece 1 opposite to the adhesive tape 23 forms a first color area 61, and the surface of the first pole piece 1 opposite to the area on the second pole piece 2 where the adhesive tape 23 is not pasted forms a second color area 62;
[0049] After the battery cell is disassembled, the first color area 61 is visible as a purple spot area, while the second color area 62 is visible as a golden area. The colors of the first color area 61 and the second color area 62 are different. Specifically, the RGB value range of the first color area is (112±45, 104±45, 104±45), and / or the RGB value range of the second color area is (145±50, 135±50, 96±50). By testing the RGB values of the two color areas, the first color area and the second color area can be distinguished. This is because during the charging process of the lithium-ion battery, the active lithium of the second pole piece 2 is released, passes through the diaphragm 3, and reaches the first pole piece 1; due to the presence of the adhesive tape 23 covering the second pole piece 2, it is difficult to embed lithium in the area opposite to the adhesive tape 23 of the first pole piece 1, and the SOC entering this area is much lower than that of the uncovered area. When the battery is disassembled in the fully charged state, it can be observed that the area of the first pole piece 1 covered by the adhesive tape 23 shows a purple spot phenomenon, which is significantly different from the golden fully charged area of the uncovered area.
[0050] like Figure 5 As shown in the left figure, it is worth noting that since the first electrode 1 is pre-lithiated on the entire surface, the first color area 61 that is not fully charged can still show the characteristics of the lithiated area and the non-lithiated area (i.e., the bright area and the dark area), and the first color area 61 forms a first color bright area 611 and a first color dark area 612 that alternate between light and dark in the first direction of the first electrode 1; Figure 5 The middle picture is an enlarged image of the boxed area in the left picture.
[0051] The relationship between the number of bright areas in the first color area 61 and the length of the first color area 61 is measured by observing with a high-power 3D microscope. The number of first color bright areas in the first color area 61 is Y, and the length of the first color area 61 is X μm. Then the relationship between X and Y satisfies: X / 2000≤Y<X / 100.
[0052] like Figure 5 As shown, in this embodiment, the length of the first color area 61 on the first pole piece 1 is 4 mm, and the number of the first color bright areas 611 is 6. The width of the first color area 61 covered by the general model adhesive is about 3-6 mm, and the average width of the first color bright area 611 is 0.2-0.6 mm, and the average width of the first color dark area 612 is roughly equivalent to the average width of the first color bright area 611.
[0053] Through high-power 3D microscope observation, there are obvious interface features at the boundary between the first color bright area 611 and the first color dark area 612, such as Figure 5 As shown in the left figure. A 3D high-definition 3D image is synthesized using a 3D microscope, and then a height difference measurement tool is used to measure the height difference between the first color bright area 611 and the first color dark area 612 of the first color area 61, and the height difference is 0.02-30μm.
[0054] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.
[0055] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.
[0056] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed or recombined, and these decompositions or recombinations should be regarded as equivalent solutions of the present application.
[0057] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
[0058] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.
[0059] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.
Claims
1. An electrode plate, characterized in that: include: A first pole piece, the first pole piece having a first surface and a second surface arranged opposite to each other, a first active material layer being arranged on the first surface and the second surface respectively, and the first pole piece having a first direction and a second direction; Bright areas and dark areas are alternately arranged on the first active material layer along a first direction of the first pole piece, the bright areas extend to an edge of the first pole piece along a second direction of the first pole piece, and the dark areas extend to an edge of the first pole piece along the second direction of the first pole piece; At least part of the bright area extends to the side end surface of the first pole piece.
2. The electrode plate according to claim 1, characterized in that: At least part of the dark area extends to the side end surface of the first pole piece; The bright area and the dark area extending to the side end surface of the first pole piece are alternately arranged on the side end surface of the first pole piece.
3. The electrode plate according to claim 2, characterized in that: The width of the bright region is in the range of 100-2000 μm, and / or, The width of the dark area ranged from 100–2000 μm.
4. A battery cell, characterized in that: It comprises the electrode plate as described in any one of claims 1-3, and also comprises a second plate, wherein the second plate has a third surface and a fourth surface arranged opposite to each other, and a second active material layer is respectively arranged on the third surface and the fourth surface.
5. The battery cell according to claim 4, characterized in that: The second pole piece, the diaphragm and the first pole piece are wound together to form the battery cell, and the head and / or tail of the second pole piece in the first direction are respectively affixed with adhesive tape, and the adhesive tape covers the surface of the second active material layer on the side of the second pole piece opposite to the first pole piece.
6. The battery cell according to claim 5, characterized in that: The size of the adhesive tape in the first direction is greater than the size of the first pole piece in the first direction.
7. The battery cell according to claim 5, characterized in that: A first color zone is formed on the surface of the active material layer of the first electrode opposite to the adhesive tape, and a second color zone is formed on the surface of the first electrode opposite to the area on the second electrode not pasted with the adhesive tape, and the RGB values of the first color zone and the second color zone are different.
8. The battery cell according to claim 7, characterized in that: The RGB value range of the first color area is (112±45, 104±45, 104±45), and / or, The RGB value range of the second color area is (145±50, 135±50, 96±50).
9. The battery cell according to claim 7, characterized in that: The first color region forms a first color bright region and a first color dark region that alternate between light and dark in a first direction of the first pole piece.
10. The battery cell according to claim 9, characterized in that: The number of the first color bright areas in the first color area is Y, the length of the first color area is X μm, and the relationship between X and Y satisfies: X / 2000≤Y<X / 100.
11. The battery cell according to claim 9, characterized in that: There is a height difference between the surfaces of the first bright color area and the first dark color area in the first color area, and the height difference is 0.02-30 μm.