Current collector, pole piece and battery

Abstract

The utility model provides a current collector, a pole piece and a battery, and relates to the technical field of batteries. The current collector comprises a coating area, the coating area comprises a first area, a second area and a third area which are sequentially arranged in the width direction of the current collector, the second area is located between the first area and the third area, the first area is provided with a plurality of first through holes, the third area is provided with a plurality of second through holes, and the second area is a non-porous area. As the second region is a non-porous region, the structural strength of the middle part of the current collector can be improved, and the middle part of the current collector is not easy to crack when the battery is expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a current collector, a pole piece and a battery. BACKGROUND

[0002] The wettability of electrolyte has an important influence on the cycle life and charge-discharge rate of the battery. During the charging process of the battery, lithium ions need to be transported through the electrolyte after being deintercalated from the active material of the positive pole piece, so as to reach the negative pole piece and be intercalated into the active material thereof. During the discharging process, lithium ions are deintercalated from the negative pole piece and return to the positive pole piece through the electrolyte.

[0003] In the battery technology, the current collector is a key component of the pole piece, which plays a role of bearing active material, collecting current and conducting current. In order to improve the wettability of the electrolyte, the related technology adopts the method of making pores on the current collector. However, this method can improve the wettability of the electrolyte to a certain extent, but it will lead to a decrease in the structural strength of the current collector, and then lead to cracks in the current collector when the battery expands. SUMMARY

[0004] Embodiments of the present application provide a current collector, a pole piece and a battery, which can improve the technical problem that making pores on the current collector leads to a decrease in the structural strength of the current collector, and then leads to cracks in the current collector when the battery expands.

[0005] In a first aspect, embodiments of the present application provide a current collector, which comprises a coating area, the coating area comprising a first area, a second area and a third area arranged in sequence along a width direction of the current collector, the second area being located between the first area and the third area, the first area being provided with a plurality of first through holes, the third area being provided with a plurality of second through holes, and the second area being a non-porous area.

[0006] In some embodiments, along the width direction of the current collector, the proportion of the second area to the current collector ranges between 1 / 9 and 1 / 3.

[0007] In some embodiments, along the thickness direction of the current collector, the range of the orthographic projection area of the first through hole is between 2mm 2 and 4mm 2 ; and / or,

[0008] Along the thickness direction of the current collector, the range of the orthographic projection area of the second through hole is between 2mm 2 and 4mm 2 .

[0009] In some embodiments, the first through hole and / or the second through hole is a triangular hole.

[0010] In some embodiments, the first through hole is an equilateral triangle hole, and a side length of the equilateral triangle hole ranges from 0.25 mm to 0.35 mm; and / or,

[0011] The second through hole is an equilateral triangle hole, and a side length of the equilateral triangle hole ranges from 0.25 mm to 0.35 mm.

[0012] In some embodiments, the first area has a first edge away from the second area, and the first through hole is arranged away from the first edge in a width direction of the current collector; and / or,

[0013] The third area has a second edge away from the second area, and the second through hole is arranged away from the second edge in the width direction of the current collector.

[0014] In some embodiments, the first area has a first edge away from the second area, and the first through hole is arranged away from the first edge in a width direction of the current collector, and a distance between the first through hole closest to the first edge and the first edge ranges from 2 mm to 5 mm; and / or,

[0015] The second area has a first edge away from the second area, and the second through hole is arranged away from the second edge in a width direction of the current collector, and a distance between the second through hole closest to the second edge and the second edge ranges from 2 mm to 5 mm.

[0016] In some embodiments, the current collector further comprises:

[0017] A tab area connected to at least one side of the current collector along a length direction of the current collector.

[0018] In a second aspect, embodiments of the present application provide a tab, the tab comprising the current collector of any of the embodiments of the first aspect.

[0019] In a third aspect, embodiments of the present application provide a battery, the battery comprising the current collector of any of the embodiments of the first aspect or the tab of any of the embodiments of the second aspect.

[0020] The beneficial effects of embodiments of the present application are as follows:

[0021] In embodiments of the present application, by arranging a plurality of first through holes in the first area, a plurality of second through holes in the third area, and arranging the second area as a non-hole area, when the current collector is used in a battery, electrolyte can diffuse through the first through hole and the third through hole, and the wettability of the electrolyte is higher, and since the second area is a non-hole area, the structural strength of the middle part of the current collector can be improved, so that the middle part of the current collector is not easy to crack when the battery expands. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and all other drawings obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0023] Figure 1 is a schematic diagram of the three-dimensional structure of the current collector provided by the embodiments of the present application;

[0024] Figure 2 is a front view of the current collector provided by the embodiments of the present application;

[0025] Figure 3 is a schematic diagram of the structure of the current collector provided by some other embodiments of the present application;

[0026] Figure 4 is a schematic diagram of the structure of the current collector provided by some other embodiments of the present application;

[0027] Figure 5 is a schematic diagram of the structure of the pole piece provided by the embodiments of the present application.

[0028] Reference signs:

[0029] 100 - current collector; 10 - coating area; 11 - first area; 111 - first through hole; 12 - second area; 13 - third area; 131 - second through hole; 14 - first edge; 15 - second edge; 20 - active material layer; 30 - tab area; 31 - first tab; 32 - second tab; 1000 - pole piece; Z - width direction. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application.

[0031] In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, the orientation words such as “upper” and “lower” generally refer to the upper and lower in the actual use state of the device, and specifically refer to the direction of the drawing surface in the drawings.

[0032] The terms "first", "second", "third", etc. are used only for descriptive purposes and do not connote or imply relative importance or a number of the indicated technical features. Thus, features defined with "first", "second" or "third" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically defined.

[0033] In the description of the present application, the term "comprising", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, and also includes other elements not explicitly listed.

[0034] In the description of the embodiments of the present application, the words "example" or "for example" or the like are used to mean example, illustration or description. Any embodiment or design scheme described as "for example" in the embodiments of the present application is not interpreted as more preferred or having more advantages than another embodiment or design scheme. The words "example" or "for example" or the like are intended to present the relative concept in a clear manner.

[0035] During the use of the battery, the middle part of the battery is farther away from the end cover than the two ends, and the heat dissipation effect is not as good as that of the two ends, resulting in more obvious expansion of the middle part of the battery. This expansion makes the middle part of the current collector prone to deformation.

[0036] In the related art, punching the current collector reduces its strength, making the current collector more prone to cracking. If the middle part of the current collector is punched, when the middle part of the battery expands, the deformation of the middle part of the current collector will make it more prone to cracking.

[0037] In view of this, the embodiments of the present application provide a current collector, it should be understood that the current collector provided by the embodiments of the present application can be a positive electrode current collector or a negative electrode current collector, and the structure of the current collector will be described in detail below in conjunction with the drawings.

[0038] Referring to Figure 1 and Figure 2 The current collector 100 includes a coated area 10, and the coated area 10 is used to coat an active material layer 20.

[0039] The material of the current collector 100 can be copper, aluminum, etc.

[0040] In actual application, along the thickness direction of the current collector 100, the two large faces of the coated area 10 can be used to coat the active material layer 20 (for example, as shown in FIG. 1A). Figure 5The active material layer 20 is a positive active material layer if the current collector 100 is a positive current collector 100. The positive active material layer includes a positive active material, which can include but is not limited to lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The active material layer 20 is a negative active material layer if the current collector 100 is a negative current collector 100. The negative active material layer includes a negative active material, which can include but is not limited to carbon, silicon, etc.

[0041] The coating area 10 includes a first area 11, a second area 12 and a third area 13 arranged in sequence along the width direction Z of the current collector 100, the second area 12 being located between the first area 11 and the third area 13, the first area 11 being provided with a plurality of first through holes 111, the third area 13 being provided with a plurality of second through holes 131, and the second area 12 being a non-porous area.

[0042] It can be understood that, by such arrangement of the coating area 10, the current collector 100 presents a structure of non-porous area in the middle and porous area on both sides in the width direction Z of the current collector 100.

[0043] Exemplarily, as shown in FIG. 1, Figure 2 the first area 11, the second area 12 and the third area 13 can be arranged in sequence from top to bottom, that is, the current collector 100 is porous on the upper and lower parts, and is not punched in the middle part. The dashed line made along the edge of the plurality of first through holes 111 close to the second area 12 can be understood as the boundary line between the first area 11 and the second area 12. The dashed line made along the edge of the plurality of second through holes 131 close to the second area 12 can be understood as the boundary line between the second area 12 and the third area 13. It should be understood that the boundary line between the first area 11 and the second area 12 changes with the arrangement mode of the plurality of first through holes 111. Therefore, the boundary line between the first area 11 and the second area 12 can be parallel to the length direction of the current collector 100, or can intersect the length direction of the current collector 100, or even the boundary line between the first area 11 and the second area 12 can be a broken line (as shown in FIG. 2). Figure 3 Similarly, the boundary line between the third area 13 and the second area 12 changes with the arrangement mode of the plurality of second through holes 131. Therefore, the boundary line between the third area 13 and the second area 12 can be parallel to the length direction of the current collector 100, or can intersect the length direction of the current collector 100, or even the boundary line between the third area 13 and the second area 12 can be a broken line (as shown in FIG. 3). Figure 3

[0044] The shape of the first through hole 111 can include one or more of a circular hole, a rectangular hole, a triangular hole, and a rhombic hole.

[0045] The shape of the second through hole 131 can include one or more of a circular hole, a rectangular hole, a triangular hole, and a rhombic hole. ​

[0046] In an embodiment, the first through holes 111 and the second through holes 131 have the same shape to improve the consistency of the interface of the current collector 100.

[0047] In the embodiment, by arranging a plurality of first through holes 111 in the first area 11, a plurality of second through holes 131 in the third area 13, and arranging the second area 12 as a non-hole area, when the current collector 100 is used in a battery, the electrolyte can diffuse through the first through holes 111 and the third through holes, and the wettability of the electrolyte is higher. Since the second area 12 is a non-hole area, the structural strength of the middle part of the current collector 100 can be improved, so that the middle part of the current collector 100 is not easy to crack when the battery expands.

[0048] It can be understood that the current collector 100 provided in the embodiment can balance the structural strength of the current collector 100 and the wettability of the electrolyte.

[0049] In some embodiments, along the width direction Z of the current collector 100, the proportion of the second area 12 to the current collector 100 ranges between 1 / 9 and 1 / 3. In other words, the width of the second area 12 accounts for a range of 1 / 9 to 1 / 3 of the width of the current collector 100.

[0050] Exemplarily, along the width direction Z of the current collector 100, the proportion of the second area 12 to the current collector 100 can be 1 / 9, 4 / 27, 5 / 27, 6 / 27, 7 / 27, 8 / 27, 1 / 3, and any value therebetween.

[0051] In an embodiment, along the width direction Z of the current collector 100, the current collector 100 is divided into three equal parts. In other words, in the width of the current collector 100, the widths of the first area 11, the second area 12, and the third area 13 each account for 1 / 3.

[0052] By making the proportion of the second area 12 to the current collector 100 greater than 1 / 9, the proportion of the second area 12 in the current collector 100 will not be too small, so that a current collector 100 with high structural strength can be obtained. By making the proportion of the second area 12 to the current collector 100 less than 1 / 3, under the condition that the total area of the coating area 10 is constant, the proportion of the second area 12 in the current collector 100 will not be too large, and the area left for the first area 11 and the third area 13 will not be too small, which is conducive to arranging the first through holes 111 in the first area 11 and arranging the second through holes 131 in the third area 13, thereby improving the wettability of the electrolyte. Therefore, the proportion of the second area 12 to the current collector 100 ranges between 1 / 9 and 1 / 3, which can further balance the structural strength of the current collector 100 and the wettability of the electrolyte.

[0053] In some embodiments, along the thickness direction of the current collector 100, the area of the orthographic projection of the first through hole 111 ranges between 2 mm 2 and 4 mm 2between.

[0054] Exemplarily, the first through hole 111 can have a projection area of 2mm 2 , 2.2mm 2 , 2.5mm 2 , 2.6mm 2 , 2.8mm 2 , 3mm 2 , 3.4mm 2 , 3.7mm 2 , 4mm 2 , or any value therebetween.

[0055] In the embodiment, the first through hole 111 has a projection area greater than 2mm 2 , so that the first through hole 111 is not too small, which is conducive to the diffusion of the electrolyte from the first through hole 111 and improves the wettability of the electrolyte. The first through hole 111 has a projection area less than 4mm 2 , so that the first through hole 111 is not too large, and the first area 11 has a large surface area, which facilitates the coating of the active material layer 20 on the first area 11 and reduces the coating difficulty of the active material layer 20. Therefore, the projection area of the first through hole 111 is between 2mm 2 and 4mm 2 , which can balance the wettability of the electrolyte and the coating difficulty of the active material layer 20.

[0056] In some embodiments, along the thickness direction of the current collector 100, the second through hole 131 has a projection area ranging from 2mm 2 to 4mm 2 .

[0057] Exemplarily, the second through hole 131 can have a projection area of 2mm 2 , 2.2mm 2 , 2.5mm 2 , 2.6mm 2 , 2.8mm 2 , 3mm 2 , 3.4mm 2 , 3.7mm 2 , 4mm 2 , or any value therebetween.

[0058] The second through hole 131 has a projection area greater than 2mm 2 , so that the second through hole 131 is not too small, which is conducive to the diffusion of the electrolyte from the second through hole 131 and improves the wettability of the electrolyte. The second through hole 131 has a projection area less than 4mm 2, the second through hole 131 will not be too large, and the third region 13 has a large surface area, facilitating coating of the active material layer 20 on the third region 13 and reducing the difficulty of coating the active material layer 20. Therefore, the second through hole 131 has a normal projection area of 2mm 2 ~ 4mm 2 , which can balance the wettability of the electrolyte and the coating difficulty of the active material layer 20.

[0059] In some embodiments, the first through hole 111 is a triangular hole. In some embodiments, the second through hole 131 is a triangular hole.

[0060] Compared with a circular hole, a triangular hole has a higher space utilization rate. In the case of the same total area of the required through hole, triangular holes can be arranged more sparsely, i.e., the distance between adjacent triangular holes can be larger, which is conducive to reducing the coating difficulty of the active material layer 20.

[0061] In some embodiments, the first through hole 111 is an equilateral triangular hole. Due to the equal three sides of the equilateral triangle, the stress distribution of the first through hole 111 is more uniform, which helps to improve the structural stability of the first region 11 and further improve the structural stability of the current collector 100 and reduce the risk of deformation of the current collector 100.

[0062] Further, the length of the side of the first through hole 111 ranges from 0.25mm to 0.35mm. Within this range, the structure of the current collector 100 is more stable.

[0063] For example, the length of the side of the first through hole 111 can be 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.35mm, and any value therebetween, etc.

[0064] In some embodiments, the second through hole 131 is an equilateral triangular hole. Due to the equal three sides of the equilateral triangle, the stress distribution of the second through hole 131 is more uniform, which helps to improve the structural stability of the third region 13 and further improve the structural stability of the current collector 100 and reduce the risk of deformation of the current collector 100.

[0065] Further, the length of the side of the second through hole 131 ranges from 0.25mm to 0.35mm. Within this range, the structure of the current collector 100 is more stable.

[0066] For example, the length of the side of the second through hole 131 can be 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.35mm, and any value therebetween, etc.

[0067] In some embodiments, the first region 11 has a first edge 14 facing away from the second region 12, and the first through hole 111 is spaced apart from the first edge 14 in the width direction Z of the current collector 100.

[0068] Due to the limitation of machining precision, the edges of the current collector 100 are prone to defects such as burrs and sawteeth. When the current collector 100 is under stress, the defects can worsen and generate micro-cracks. If the distance between the first through hole 111 and the first edge 14 is too small, the micro-cracks can extend to the first through hole 111, causing the first region 11 to break.

[0069] In the present embodiment, by spacing apart the first through hole 111 from the first edge 14, the distance between the first through hole 111 and the first edge 14 can be increased, reducing the risk of the first region 11 breaking.

[0070] In some embodiments, the third region 13 has a second edge 15 facing away from the second region 12, and the second through hole 131 is spaced apart from the second edge 15 in the width direction Z of the current collector 100. It can be understood that the second edge 15 and the first edge 14 are two edges opposite to the coating region.

[0071] Due to the limitation of machining precision, the edges of the current collector 100 are prone to defects such as burrs and sawteeth. When the current collector 100 is under stress, the defects can worsen and generate micro-cracks. If the distance between the second through hole 131 and the second edge 15 is too small, the micro-cracks can extend to the second through hole 131, causing the third region 13 to break.

[0072] In the present embodiment, by spacing apart the second through hole 131 from the second edge 15, the distance between the second through hole 131 and the second edge 15 can be increased, reducing the risk of the third region 13 breaking.

[0073] In some embodiments, the first through hole 111 is spaced apart from the first edge 14 in the width direction Z of the current collector 100, and the spacing distance between the first through hole 111 closest to the first edge 14 and the first edge 14 is in the range of 2mm-5mm. In this way, the first through hole 111 is not too close to the first edge 14, and the area available for hole making in the first region 11 is not too small.

[0074] For example, the spacing distance can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, and any value therebetween.

[0075] In some embodiments, the second through hole 131 is arranged at a distance from the second edge 15 in the width direction Z of the current collector 100, and the second through hole 131 closest to the second edge 15 is arranged at a distance ranging from 2 mm to 5 mm from the second edge 15. In this way, the second through hole 131 is not too close to the second edge 15, and the area of the third region 13 available for forming holes is not too small.

[0076] For example, the distance can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or any value therebetween.

[0077] Referring to Figure 2 In some embodiments, the current collector 100 further comprises a tab region 30 for connecting a tab (not shown in the figure) to lead out an electrode. The tab region 30 is connected to at least one side of the current collector 100 along the length direction thereof.

[0078] Specifically, the tab region 30 comprises a first tab 31 and a second tab 32. Along the length direction of the current collector 100, the first tab 31 and the second tab 32 can be arranged on the same side of the coated region 10 to form a same-side tab. The first tab 31 and the second tab 32 can also be arranged on opposite sides of the coated region 10 to form an opposite-side tab.

[0079] Referring to Figure 2 In some embodiments, the current collector 100 is used in a stacked battery, and along the length direction of the current collector 100, the first tab 31 and the second tab 32 are arranged on opposite sides of the coated region 10, and both the first tab 31 and the second tab 32 are connected to the second region 12. The first tab 31 and the second tab 32 can be full tabs.

[0080] Referring to Figure 4 In other embodiments, the current collector 100 is used in a wound battery, and along the width direction Z of the current collector 100, the first tab 31 and the second tab 32 are arranged on the same side of the coated region 10.

[0081] Referring to Figure 5 Embodiments of the present application also provide a pole piece 1000, which comprises the current collector 100 provided by any of the above embodiments. The coated region 10 of the current collector 100 is provided with an active material layer 20.

[0082] Since the pole piece 1000 comprises the current collector 100 described above, the pole piece 1000 has the beneficial effects of the current collector 100 described above, which will not be described again here for brevity.

[0083] Embodiments of the present application provide a battery, which comprises the current collector 100 provided by any of the above embodiments or the pole piece 1000 provided by any of the above embodiments.

[0084] Since the battery includes the above-mentioned current collector 100 or the tab 1000, the battery has the beneficial effects of the above-mentioned current collector 100 or the tab 1000, which will not be described here for the sake of brevity.

[0085] The above describes the embodiments of the present application in detail, and the principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A current collector characterized by comprising: The application relates to a current collector and a polar plate. The coating region comprises a first region, a second region and a third region arranged in sequence along the width direction of the current collector, the second region is located between the first region and the third region, the first region is provided with a plurality of first through holes, the third region is provided with a plurality of second through holes, and the second region is a non-hole region.

2. The current collector of claim 1, wherein The proportion of the second region to the current collector along the width direction of the current collector ranges between 1 / 9 and 1 / 3.

3. The current collector of claim 1, wherein The first through-hole has a projected area in the thickness direction of the current collector ranging between 2 mm 2 ~ 4 mm 2 ; and / or, The second through-hole has a range of 2mm 2 ~ 4mm 2 in the area of the orthogonal projection of the second through-hole in the thickness direction of the current collector.

4. The current collector according to any one of claims 1 to 3, wherein The first through hole and / or the second through hole is a triangular hole.

5. The current collector of claim 4, wherein The first through hole is an equilateral triangular hole, the side length of the equilateral triangular hole ranges between 0.25 mm and 0.35 mm; and / or, The second through hole is an equilateral triangular hole, the side length of the equilateral triangular hole ranges between 0.25 mm and 0.35 mm.

6. The current collector of any one of claims 1-3, wherein The first region has a first edge away from the second region, and the first through hole is arranged in the width direction of the current collector and is spaced apart from the first edge; and / or, The third region has a second edge away from the second region, and the second through hole is arranged in the width direction of the current collector and is spaced apart from the second edge.

7. The current collector of any one of claims 1-3, wherein The first region has a first edge away from the second region, and the first through hole is arranged in the width direction of the current collector and is spaced apart from the first edge, and the spacing distance between the first through hole closest to the first edge and the first edge ranges between 2 mm and 5 mm; and / or, The second region has a second edge away from the second region, and the second through hole is arranged in the width direction of the current collector and is spaced apart from the second edge, and the spacing distance between the second through hole closest to the second edge and the second edge ranges between 2 mm and 5 mm.

8. The current collector of any one of claims 1-3, wherein, The current collector further comprises: A tab region connected to at least one side of the current collector along the length direction of the current collector.

9. A pole piece characterized by, The application relates to a current collector and a polar plate.

10. A battery, characterized by The application relates to a current collector and a polar plate.

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