Pole piece, lithium ion battery containing same and electric device

Abstract

The utility model provides a kind of pole piece and contain its lithium ion battery and electric device, it is related to lithium ion battery technical field.The pole piece includes current collector and the active material layer of setting in current collector one side, the active material layer surface has several equal-width parallel bottom arc grooves, the several bottom arc grooves are parallel with pole piece width direction, and the groove depth of roll head is less than the groove depth of roll tail, and the ratio of groove depth and active material layer thickness is 0.05~0.7:1.The utility model can effectively improve the electrolyte wetting effect of pole piece, improve the electrical performance of battery by the groove setting on the above active material layer;Meanwhile, it can also prevent the fracture of pole piece, improve the yield of pole piece, and further improve the yield of battery.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to an electrode sheet and a lithium-ion battery and power device containing the electrode sheet. Background Technology

[0002] In existing battery technologies, methods such as increasing the wetting temperature or decreasing the electrolyte viscosity are typically used to improve cell wetting. However, increasing the wetting temperature or decreasing the electrolyte viscosity degrades battery performance and cannot effectively improve cell wetting. Simultaneously, stress concentration occurs at corner areas during cell winding, leading to reduced electrolyte content and increased polarization in the electrochemical reaction. As the cell cycles, these areas exhibit interface deterioration phenomena such as purple spots and lithium plating, and may even experience cell structure distortion, further accelerating cell performance degradation and posing safety risks.

[0003] Due to the shortcomings of the aforementioned methods of increasing immersion temperature or reducing electrolyte viscosity, in recent years, patterned pressure rollers have been used in electrode processing to print micrometer-level indentations on the surface of the electrode before winding. This creates space between the positive electrode and the separator after the cell is wound, thus allowing room for the expansion of the negative electrode.

[0004] However, the pressure roller has poor adjustability, making it impossible to adjust the size, depth, and spacing of the pits created on the positive electrode surface. Furthermore, it cannot adjust these parameters according to the different stresses at different locations on the electrode. This results in insufficient space for positive electrode creation at the winding corners, causing performance degradation of the cell during cycling. In addition, since the electrode has a certain degree of elasticity, the pits created by the pressure roller may recover after hot pressing. Moreover, during cell cycling, the thickness of the electrode will continuously change during lithium extraction and insertion, which may also cause the pits to flatten. Therefore, the effect is not significant.

[0005] In view of the above, this utility model is hereby proposed. Utility Model Content

[0006] Explanation of abbreviations used in this utility model and its accompanying drawings:

[0007] A is the width of the groove;

[0008] B is the length of the groove;

[0009] H is the groove depth;

[0010] N is the number of grooves in a plurality of bottom arc-shaped grooves;

[0011] C is the distance between two adjacent grooves;

[0012] L is the length of the electrode;

[0013] W represents the electrode width;

[0014] J represents the thickness of the active material layer;

[0015] S- represents the electrode area, referring to the effective coating area of ​​the electrode (excluding the edge reserved area).

[0016] The primary objective of this invention is to provide an electrode that can effectively improve the electrolyte wetting effect of the electrode, thereby enhancing battery performance. Simultaneously, it can prevent electrode breakage, improving electrode yield and consequently, battery yield.

[0017] The second objective of this invention is to provide a lithium-ion battery.

[0018] The third objective of this utility model is to provide an electrical device.

[0019] In order to achieve the above-mentioned objectives of this utility model, the following technical solution is adopted:

[0020] The present invention provides an electrode sheet, the electrode sheet comprising a current collector and an active material layer disposed on one side of the current collector;

[0021] The surface of the active material layer has several parallel bottom arc-shaped grooves of equal width. The several bottom arc-shaped grooves are parallel to the width direction of the electrode sheet, and the groove depth at the beginning of the roll is less than the groove depth at the end of the roll.

[0022] The ratio of the groove depth to the active material layer thickness is 0.05~0.7:1.

[0023] Furthermore, the groove length B is less than the electrode width W, and the sum of the widths of the several bottom arc-shaped grooves is less than the length of the electrode.

[0024] Furthermore, the ratio of the groove length B to the electrode width W is 0.896~0.992:1.

[0025] Furthermore, the area of ​​the active material layer is smaller than the area of ​​the electrode, and the area ratio of the plurality of bottom arc-shaped grooves on the active material layer is 3.0~5.0%.

[0026] Furthermore, the ratio of the groove width A to the distance C between two adjacent grooves is 0.25~0.5:1.

[0027] Furthermore, the bottom of the groove 3 is arc-shaped or prismatic;

[0028] The end of the groove along its length is spherical.

[0029] Furthermore, the groove width A exceeds the electrode tab solder mark width by 0.5-1.0 mm.

[0030] Furthermore, the distance between the edge of the groove and the edge of the electrode sheet is ≥5mm.

[0031] This utility model provides a lithium-ion battery, which includes the aforementioned electrode plates.

[0032] This utility model provides an electrical device, which includes the aforementioned lithium-ion battery.

[0033] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0034] The electrode provided by this invention includes a current collector and an active material layer disposed on one side of the current collector. The surface of the active material layer has a plurality of parallel bottom arc-shaped grooves of equal width. The plurality of bottom arc-shaped grooves are parallel to the width direction of the electrode, and the groove depth at the beginning of the groove is less than the groove depth at the end of the groove. The ratio of the groove depth to the thickness of the active material layer is 0.1~0.7:1. This invention, through the groove arrangement on the active material layer, can effectively improve the electrolyte wetting effect of the electrode, thereby improving the battery performance; at the same time, it can also prevent electrode breakage, improve the electrode yield, and thus improve the battery yield. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the electrode structure provided by this utility model;

[0037] Figure 2 This is a schematic diagram of the electrode structure provided in Embodiment 1 of this utility model.

[0038] Icons: 1-Current collector; 2-Active material layer; 3-Bottom arc-shaped groove; A-Groove width; B-Groove length; H-Groove depth; C-Spacing between two adjacent grooves; L-Electrode length; W-Electrode width; J-Active material layer thickness. Detailed Implementation

[0039] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. To help to better understand this utility model, specific embodiments will now be described in detail.

[0040] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0043] Figure 1 This is a schematic diagram of the structure of the electrode sheet of this utility model.

[0044] According to one aspect of the present invention, an electrode includes a current collector 1 and an active material layer 2 disposed on one side of the current collector 1;

[0045] The surface of the active material layer 2 has several parallel bottom arc-shaped grooves 3 of equal width. The several bottom arc-shaped grooves 3 are parallel to the direction of the electrode width W, and the groove depth H at the beginning of the roll is less than the groove depth H at the end of the roll.

[0046] The ratio of the groove depth H to the thickness of the active material layer 2 is 0.05~0.7:1.

[0047] The electrode provided by this invention includes a current collector 1 and an active material layer 2 disposed on one side of the current collector 1. The surface of the active material layer 2 has a plurality of parallel bottom arc-shaped grooves 3 of equal width. The plurality of bottom arc-shaped grooves 3 are parallel to the width W direction of the electrode, and the groove depth H at the beginning of the groove is less than the groove depth H at the end of the groove. At the same time, the ratio of the groove depth H to the thickness of the active material layer 2 is 0.05~0.7:1. Through the groove setting on the active material layer 2, this invention can effectively improve the electrolyte wetting effect of the electrode and improve the performance of the battery.

[0048] It should be noted that the ratio of groove depth H to active material layer thickness J in this invention, which is set to 0.1~0.7 (numerical range), effectively ensures battery performance. However, excessively deep grooves may disrupt the longitudinal heat conduction channels of the electrode, weakening the overall heat dissipation capacity of the battery. Especially in high-speed charge and discharge scenarios, heat is difficult to effectively dissipate through the tabs, leading to a decrease in cycle life. The groove depth needs to be designed in coordination with the electrode coating thickness. Simultaneously, excessively thin or thick coatings of the active material layer 2 will affect the active material loading and lithium-ion diffusion path. If the groove depth is not adapted to the coating thickness, it may lead to excessive compression or uneven distribution of active material in local areas, reducing effective capacity. Inappropriately deep grooves may alter the internal electron conduction network of the electrode. That is, too shallow: insufficient contact area between the conductive agent and the active material, increasing interface resistance; too deep: damaging the bonding strength between the current collector 1 and the active material, causing an increase in contact resistance.

[0049] In a preferred embodiment of this invention, the groove depth should not exceed 50% of the total electrode thickness. When the groove depth exceeds 50% of the total electrode thickness, the electrode's bending resistance decreases significantly, making it prone to breakage during stacking or winding processes, thus increasing the risk of micro-short circuits inside the battery.

[0050] In a preferred embodiment of this utility model, the groove length B is less than the electrode width W, and the sum of the widths of the plurality of bottom arc-shaped grooves 3 is less than the length of the electrode.

[0051] That is: B < W, N*A < L.

[0052] As a preferred embodiment, the groove length B is 56-62mm. When WB=0 (W minus B equals 0), the risk of strip breakage and cracking of the electrode during the winding process is greatest; when 0≤WB≤3mm, no holes are formed in the overhang area, reducing edge lithium plating; when 3mm≤WB≤10mm, no holes are formed in the thinning area, reducing the loss of active material.

[0053] In the preferred embodiment described above, the ratio of the groove length B to the electrode width W is 0.896~0.992:1, that is: B / W=89.6~99.2%.

[0054] In a preferred embodiment of the present invention, the area of ​​the active material layer 2 is smaller than the area S of the electrode sheet, and the area ratio of the plurality of bottom arc-shaped grooves 3 on the active material layer 2 is 3.0~5.0%.

[0055] That is: N*A*B / S electrode = 3.0~5.0%, S electrode < L*W.

[0056] As a preferred embodiment, the larger the mass / volume / area of ​​the grooves or single holes on the electrode, the lower the mechanical strength of the wound electrode, making it more prone to cracking and breakage; conversely, insufficient loss results in a poorer expected performance improvement. Therefore, this invention limits the area ratio of several bottom arc-shaped grooves 3 on the active material layer 2 to 3.0~5.0%.

[0057] In a preferred embodiment of this utility model, the ratio of the groove width A to the distance C between two adjacent grooves is 0.25~0.5:1, that is: A / C=0.25~0.5.

[0058] In the preferred embodiment described above, the groove width A is 40-500 μm, and the distance C between two adjacent grooves is 100-2000 μm. Therefore, the spacing notation in this invention should be the current A+C, typically 2-4 times the groove size.

[0059] In a preferred embodiment of this utility model, the bottom of the groove is arc-shaped or prismatic, and the end of the groove along its length is arc-shaped.

[0060] As a preferred embodiment, the bottom of the groove of this utility model is arc-shaped or prismatic, which facilitates the entry of electrolyte into the groove for wetting, and at the same time makes it more convenient to process.

[0061] In a preferred embodiment of this utility model, the groove width A exceeds the electrode tab solder mark width by 0.5-1.0 mm.

[0062] In a preferred embodiment of this utility model, the distance between the edge of the groove and the edge of the electrode sheet is ≥5mm.

[0063] According to one aspect of the present invention, a lithium-ion battery includes the aforementioned electrode.

[0064] The electrode provided by this invention can be widely used in lithium-ion batteries.

[0065] According to one aspect of the present invention, an electrical device includes the aforementioned lithium-ion battery.

[0066] The present invention provides an electrical device, which includes the aforementioned lithium-ion battery, and the lithium-ion battery can be used to supply power to the electrical device.

[0067] Example 1

[0068] Figure 1 This is a schematic diagram of the structure of the electrode sheet of this utility model.

[0069] Figure 2 This is a schematic diagram of the electrode structure provided in Embodiment 1 of this utility model.

[0070] See Figure 1 , Figure 2 An electrode sheet, comprising a current collector 1 and an active material layer 2 disposed on one side of the current collector 1, wherein the surface of the active material layer 2 has a plurality of parallel bottom arc-shaped grooves 3 of equal width, the plurality of bottom arc-shaped grooves 3 being parallel to the width W direction of the electrode sheet, and the groove depth H at the beginning of the roll is less than the groove depth H at the end of the roll.

[0071] The groove depth H is 25μm, the groove width A is 25μm, the groove length B is 60mm, and the distance C between two adjacent grooves is 200μm.

[0072] The thickness of the active material layer 2 is 40 μm;

[0073] The electrode length L is 100mm, and the electrode width W is 62.5mm;

[0074] The groove width A exceeds the electrode tab solder mark width by 1.0 mm.

[0075] The electrode provided by this invention includes a current collector 1 and an active material layer 2 disposed on one side of the current collector 1. The surface of the active material layer 2 has several parallel grooves of equal width. The several bottom arc-shaped grooves 3 are parallel to the width W direction of the electrode, and the groove depth H at the beginning of the groove is less than the groove depth H at the end of the groove. Furthermore, the ratio of the groove depth H to the thickness of the active material layer 2 is 25:40. Through the groove arrangement on the active material layer 2, this invention can effectively improve the electrolyte wetting effect of the electrode and enhance the battery performance.

[0076] In this embodiment, the groove length B is 60.5 mm, and the ratio of the groove length B to the electrode width W is 60.5:62.5.

[0077] In this embodiment, the bottom of the groove is arc-shaped, and the end of the groove along its length is arc-shaped.

[0078] In this embodiment, the groove width A exceeds the electrode tab solder mark width by 1.0 mm, and the distance between the groove edge and the electrode edge is ≥5 mm.

[0079] Example 2

[0080] An electrode sheet includes a current collector 1 and an active material layer 2 disposed on one side of the current collector 1. The surface of the active material layer 2 has a plurality of parallel bottom arc-shaped grooves 3 of equal width. The plurality of bottom arc-shaped grooves 3 are parallel to the width W direction of the electrode sheet, and the groove depth H at the beginning of the roll is less than the groove depth H at the end of the roll.

[0081] The groove depth H is 3μm, the groove width A is 40μm, the groove length B is 56mm, and the distance C between two adjacent grooves is 100μm;

[0082] The thickness of the active material layer 2 is 35 μm;

[0083] The electrode length L is 100mm, and the electrode width W is 62.5mm;

[0084] The groove width A exceeds the electrode tab solder mark width by 0.5 mm.

[0085] In this embodiment, the groove length B is 56mm, and the ratio of the groove length B to the electrode width W is 56:62.5.

[0086] In this embodiment, the bottom of the groove is arc-shaped, and the end of the groove along its length is arc-shaped.

[0087] In this embodiment, the groove width A exceeds the electrode tab solder mark width by 1.0 mm, and the distance between the groove edge and the electrode edge is ≥5 mm.

[0088] Example 3

[0089] An electrode sheet includes a current collector 1 and an active material layer 2 disposed on one side of the current collector 1. The surface of the active material layer 2 has a plurality of parallel bottom arc-shaped grooves 3 of equal width. The plurality of bottom arc-shaped grooves 3 are parallel to the width W direction of the electrode sheet, and the groove depth H at the beginning of the roll is less than the groove depth H at the end of the roll.

[0090] The groove depth H is 70μm, the groove width A is 500μm, the groove length B is 62mm, and the distance C between two adjacent grooves is 2000μm;

[0091] The thickness of the active material layer 2 is 80 μm;

[0092] The electrode length L is 100mm, and the electrode width W is 62.5mm;

[0093] The groove width A exceeds the electrode tab solder mark width by 0.8 mm.

[0094] In this embodiment, the groove length B is 62mm, and the ratio of the groove length B to the electrode width W is 62:62.5.

[0095] In this embodiment, the bottom of the groove is arc-shaped, and the end of the groove along its length is arc-shaped.

[0096] In this embodiment, the groove width A exceeds the electrode tab solder mark width by 1.0 mm, and the distance between the groove edge and the electrode edge is ≥5 mm.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An electrode sheet, characterized in that, The electrode includes a current collector and an active material layer disposed on one side of the current collector; The surface of the active material layer has several parallel bottom arc-shaped grooves of equal width. These grooves are parallel to the width direction of the electrode sheet, and the groove depth at the beginning of the roll is less than the groove depth at the end of the roll. The ratio of the groove depth to the active material layer thickness is 0.05~0.7:

1.

2. The electrode sheet according to claim 1, characterized in that, The length of the groove is less than the width of the electrode, and the sum of the widths of the several bottom arc-shaped grooves is less than the length of the electrode.

3. The electrode sheet according to claim 2, characterized in that, The ratio of the groove length to the electrode width is 0.896~0.992:

1.

4. The electrode sheet according to claim 1, characterized in that, The area of ​​the active material layer is smaller than the area of ​​the electrode, and the area ratio of the plurality of bottom arc-shaped grooves on the active material layer is 3.0~5.0%.

5. The electrode sheet according to claim 1, characterized in that, The ratio of the groove width to the distance between two adjacent grooves is 0.05 to 0.5:

1.

6. The electrode sheet according to claim 1, characterized in that, The bottom of the groove is arc-shaped or prismatic; The end of the groove along its length is spherical.

7. The electrode sheet according to claim 1, characterized in that, The width of the groove exceeds the width of the electrode tab solder mark by 0.5-1.0 mm.

8. The electrode sheet according to claim 1, characterized in that, The distance between the edge of the groove and the edge of the electrode sheet is ≥5mm.

9. A lithium-ion battery, characterized in that, The lithium-ion battery includes the electrode as described in any one of claims 1 to 8.

10. An electrical device, characterized in that, The electrical device includes the lithium-ion battery as described in claim 9.

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