Battery pole piece and battery
By designing a graphite distribution with more graphite in the middle and less on both sides in the corner area of the lithium-ion battery electrode, as well as chamfering, receiving grooves and through-hole structures, the problem of abnormal cell thickness caused by lithium plating at the battery corner was solved, the electrolyte storage capacity was increased, and safety hazards were eliminated.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2026-03-06
AI Technical Summary
During the cycling process, the electrolyte in the corner area of a pouch cell is squeezed out due to the expansion and contraction of the positive and negative electrode plates, resulting in lithium plating, abnormal cell thickness, and safety hazards.
The graphite layers of the battery electrode are designed to be distributed with more in the middle and less at the edges in the corner area. Chamfers, receiving grooves and through holes are set in the corner area to increase the electrolyte storage capacity and improve the graphite dynamics in the corner area.
It effectively avoids lithium plating in corner areas, solves the problem of abnormal cell thickness in the later stages of cell cycling, eliminates safety hazards, and increases the electrolyte storage capacity, preventing electrolyte from being squeezed out.
Smart Images
Figure CN223977894U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a battery electrode and a battery. Background Technology
[0002] Currently, during the cycling process of lithium-ion batteries, both the positive and negative electrode plates expand and contract as lithium ions are inserted and extracted. In particular, the corner areas of the pouch cell core experience continuous expansion and contraction during cycling, causing the corners to shrink and the electrolyte to be squeezed out. This leads to lithium plating at the corners due to low electrolyte content in the later stages of cycling, resulting in abnormal cell thickness and posing a safety hazard. Utility Model Content
[0003] The purpose of this invention is to provide a battery electrode to solve the technical problem in the prior art where lithium deposition occurs at the corners of the electrode, leading to abnormal thickness in the later stages of cell cycling.
[0004] To achieve the above objectives, the present invention provides a battery electrode sheet, comprising: an electrode sheet body; the electrode sheet body having intersecting first and second directions, the electrode sheet body extending along the first direction, the electrode sheet body including a current collector and graphite layers respectively disposed on both sides of the current collector along the second direction;
[0005] The electrode body has a plurality of spaced corner regions in the first direction; the graphite layer has a first graphite region corresponding to the corner region, and the first graphite region has chamfers on both sides of its first edge in the first direction, the chamfers being located on the side of the first graphite region away from the current collector.
[0006] Preferably, the graphite layer has a second graphite region at a position corresponding to two adjacent first graphite regions; the second graphite region has filling portions for filling the chamfer along both sides of its first direction; the filling portions are located on the side of the second graphite region away from the current collector.
[0007] Preferably, the current collector is a copper foil layer.
[0008] Preferably, the graphite layer is provided with a receiving groove extending along the second direction at a position corresponding to the first graphite region, and the receiving groove penetrates the side of the graphite layer away from the current collector.
[0009] Preferably, each of the receiving grooves includes a funnel section and a spherical receiving section connected sequentially along the second direction; the spherical receiving section is disposed close to the current collector, and the funnel section penetrates the graphite layer on the side away from the current collector.
[0010] Preferably, there are multiple receiving slots in the same corner area.
[0011] Preferably, the number of receiving slots located in the middle of the corner area is greater than the number of receiving slots located on at least one side edge of the corner area along the first direction.
[0012] Preferably, the current collector has multiple through holes corresponding to the corner area.
[0013] Preferably, the cross-section of the through hole is wavy.
[0014] Preferably, the graphite layer includes a first graphite layer and a second graphite layer arranged sequentially along a second direction, the first graphite layer being located between the current collector and the second graphite layer, and the chamfer being disposed on the second graphite layer.
[0015] The second aspect of this utility model provides a battery that includes the battery electrode sheet described above.
[0016] The battery electrode and battery provided by this utility model have the following advantages: the amount of graphite coating on the battery electrode in the corner area is distributed with more in the middle and less on both sides, so as to increase the graphite dynamics in the corner position where lithium is prone to be deposited, avoid the situation of lithium deposition due to insufficient graphite dynamics at the corner, solve the technical problem of abnormal thickness in the later stage of cell cycle caused by lithium deposition at the corner, and eliminate safety hazards.
[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of the battery electrode sheet according to an embodiment of the present invention;
[0019] Figure 2 This is a schematic diagram of the corner area of the battery electrode sheet according to an embodiment of the present invention.
[0020] In the figure, 10 is the electrode body; 100 is the graphite layer; 110 is the first graphite region; 120 is the chamfer; 130 is the second graphite region; 140 is the filling part; 150 is the first graphite layer; 160 is the second graphite layer; 300 is the current collector; 310 is the through hole; 600 is the corner region; 700 is the receiving groove; 710 is the funnel section; and 720 is the spherical receiving section. Detailed Implementation
[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0022] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this utility model.
[0023] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0024] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0025] Please refer to the following: Figure 1 and Figure 2 The battery electrode provided in the embodiments of this utility model will now be described.
[0026] like Figure 1 and Figure 2 As shown, a battery electrode according to an embodiment of the present invention includes: an electrode body 10; the electrode body 10 has an intersecting first direction X and a second direction Y, the electrode body 10 extends along the first direction X, the electrode body 10 includes a current collector 300, and graphite layers 100 disposed on both sides of the current collector 300 along the second direction Y; the electrode body 10 has a plurality of spaced corner regions 600 in the first direction X; the graphite layers 100 have a first graphite region 110 corresponding to the corner region 600, the first graphite region 110 is provided with chamfers 120 along both sides of the first direction, the chamfers 120 are located on the side of the first graphite region 110 away from the current collector 300. Figure 1 The area within the dashed box is the corner zone of 600.
[0027] A chamfer 120 is provided in the first graphite region 110, which allows the graphite in the first graphite region 110 to have a distribution with more graphite in the middle and less at the edges, so as to form graphite with better dynamics in the corner region 600. During battery use, lithium deposition is prone to occur in the corner regions of the battery electrode in the later stages of cycling, and lithium deposition starts from the middle of the corner region 600 and slowly spreads to the entire corner region 600, and then to the larger surface area. The larger surface area is the position between two adjacent corner regions of the battery electrode. This is because in the corner region 600, the closer to the middle of the corner region 600, the greater the compression of the electrode, and the earlier the electrolyte is lost, leading to lithium deposition. Therefore, in this embodiment, the amount of graphite coating in the corner region 600 of the battery electrode has a distribution with more in the middle and less at the edges, so as to increase the graphite dynamics in the corner region where lithium deposition is prone to occur, avoid the situation where lithium deposition occurs due to insufficient graphite dynamics in the corner region, solve the technical problem in the prior art that abnormal thickness of the cell occurs in the later stages of cycling due to lithium deposition in the corner region, and eliminate safety hazards. It is understood that in this embodiment, the battery electrode is an anode electrode. However, in other embodiments, the battery electrode may also be a cathode electrode.
[0028] In some embodiments of this invention, a second graphite region 130 is provided on the graphite layer 100 at a position corresponding to the position between two adjacent first graphite regions 110; the second graphite region 130 is provided with filling portions 140 for filling the chamfer 120 along both sides of its first direction; the filling portions 140 are located on the side of the second graphite region 130 away from the current collector 300. The second graphite region 130 corresponds to the large surface of the battery electrode, and the filling portions 140 on both sides of the second graphite region 130 are used to fill the gaps of the chamfer 120, so that the graphite in the large surface area of the electrode has a distribution with less in the middle and more on both sides, in order to match the graphite dynamics required by the graphite layer 100 in different regions, avoid the problem of lithium deposition starting from the middle at the corner, and thus avoid lithium deposition at the corner of the battery electrode.
[0029] In some embodiments of this invention, the current collector 300 is a copper foil layer. Alternatively, the current collector 300 can also be an aluminum foil layer; different metal layers can be selected as the current collector depending on the actual application of the battery electrodes.
[0030] In some embodiments of this invention, the graphite layer 100 is provided with a receiving groove 700 extending along the second direction at a position corresponding to the first graphite region 110. By providing the receiving groove 700, the electrolyte storage capacity in the corner region can be increased, thereby improving the lithium plating problem that occurs in the later stages of the battery cell due to the reduction in the corner size, which causes the electrolyte to be squeezed out.
[0031] In some embodiments of this utility model, the receiving groove 700 includes a funnel section 710 and a spherical receiving section 720 connected sequentially along the second direction Y; the spherical receiving section 720 is disposed close to the current collector 300, and the funnel section 710 penetrates the graphite layer 100 on the side away from the current collector 300. The larger end of the funnel section 710 is located on the side of the graphite layer 100 away from the current collector 300, and the smaller end of the funnel section 710 is connected to the spherical receiving section 720. The funnel section 710 facilitates the entry of electrolyte into the spherical receiving section 720, and the spherical receiving section 720 can store more electrolyte to better improve the lithium plating problem that occurs in the later stages of battery cycling due to the reduction of the bend angle, which causes the electrolyte to be squeezed out.
[0032] In some embodiments of this invention, the number of receiving grooves 700 in the same corner area 600 is multiple. By providing multiple receiving grooves 700, the electrolyte storage capacity in the corner area 600 can be significantly increased, thereby better mitigating the lithium plating problem that occurs in the later stages of battery cycling due to the reduction in the corner size, which causes the electrolyte to be squeezed out.
[0033] In some embodiments of this invention, the number of receiving grooves 700 located in the middle of the corner region 600 is greater than the number of receiving grooves 700 located on at least one side edge of the corner region 600 along the first direction. That is, the distribution of the receiving grooves 700 is also more in the middle and less on the sides, which improves the problem that lithium plating preferentially starts from the middle of the corner.
[0034] In some embodiments of this invention, the current collector 300 has multiple through holes 310 at the positions corresponding to the corner region 600. By providing through holes 310 at the corner region 600, the electrolyte storage capacity of the current collector 300 in the corner region 600 can be increased, thereby improving the lithium plating problem that occurs in the later stages of battery cycling due to electrolyte squeezing out caused by the reduction in the corner size. Furthermore, the cross-section of the through holes 310 is wavy, which increases the contact area between the through holes 310 and the electrolyte, thus increasing the electrolyte storage capacity of the through holes 310. It should be noted that the multiple through holes 310 are also distributed with more in the middle and fewer at the edges, which can prevent lithium plating from preferentially starting from the corner.
[0035] In some embodiments of this utility model, the graphite layer 100 includes a first graphite layer 150 and a second graphite layer 160 sequentially disposed along a second direction. The first graphite layer 150 is located between the current collector 300 and the second graphite layer 160, and the chamfer 120 is disposed on the second graphite layer 160. That is, the graphite layer 100 is divided into two layers, and the second graphite layer 160 is a surface graphite layer, such as... Figure 1As shown, the chamfer 120 and the filling part 140 are both disposed on the second graphite layer 160, the spherical receiving section 720 is located in the first graphite layer 150, and the funnel section 710 penetrates the second graphite layer 160. Thus, the coating amount of surface graphite in the corresponding corner area of the battery electrode sheet is distributed with more in the middle and less on both sides. This increases the graphite dynamics in the corner position where lithium is easily deposited, avoids lithium deposition due to insufficient graphite dynamics in the corner area, solves the technical problem in the prior art that lithium deposition in the corner area leads to abnormal thickness in the later stage of the cell cycle, and eliminates safety hazards.
[0036] This embodiment also provides a battery, which includes the aforementioned battery electrode. The battery electrode is an anode electrode, and the amount of graphite coating in the corner region 600 of the battery electrode is distributed with more in the middle and less at the two sides. This increases the graphite kinetics at the corner location where lithium deposition is likely to occur, avoiding lithium deposition due to insufficient graphite kinetics in the corner region. This solves the technical problem in the prior art where lithium deposition in the corner region leads to abnormal thickness in the later stages of cell cycling, thus eliminating safety hazards.
[0037] In summary, the battery electrode sheet of this embodiment has at least the following technical effects: the amount of graphite coating on the surface of the battery electrode sheet in the corner area 600 is distributed with more in the middle and less at the two sides, so as to increase the graphite dynamics in the corner position where lithium is prone to be deposited, avoid the situation of lithium deposition due to insufficient graphite dynamics in the corner, solve the technical problem in the prior art that lithium deposition in the corner area leads to abnormal thickness in the later stage of the battery cell cycle, and eliminate safety hazards; and the first receiving groove 700 and through hole 310 are opened in the corner area 600, which can increase the electrolyte storage capacity at the corner, thereby improving the lithium deposition problem caused by the reduction of the corner in the later stage of the battery electrode sheet due to the squeezing of electrolyte.
[0038] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model.
Claims
1. A battery pole piece, characterized in that, The application relates to a battery pole piece, comprising: a pole piece body; the pole piece body has a first direction and a second direction intersecting with each other, the pole piece body extends along the first direction, and the pole piece body comprises a current collector and graphite layers arranged on two sides of the current collector along the second direction respectively; the pole piece body has a plurality of corner regions arranged at intervals in the first direction; the graphite layers have first graphite regions corresponding to positions of the corner regions, and the first graphite regions are provided with chamfers on two side edges in the first direction, and the chamfers are located on a side of the first graphite regions away from the current collector.
2. The battery pole piece of claim 1, wherein, the graphite layers have second graphite regions corresponding to positions between two adjacent first graphite regions; the second graphite regions are provided with filling portions for filling the chamfers on two side edges in the first direction; and the filling portions are located on a side of the second graphite regions away from the current collector.
3. The battery pole piece of claim 1, wherein, the current collector is a copper foil layer.
4. The battery pole piece of claim 1, wherein, the graphite layers are provided with accommodation grooves extending along the second direction corresponding to positions of the first graphite regions, and the accommodation grooves penetrate through a side of the graphite layers away from the current collector.
5. The battery pole piece of claim 4, wherein, the accommodation grooves each comprise a funnel section and a spherical accommodation section connected in sequence along the second direction; the spherical accommodation section is arranged close to the current collector, and the funnel section penetrates through a side of the graphite layers away from the current collector.
6. The battery pole piece of claim 5, wherein, in the same corner region, the number of the accommodation grooves is a plurality.
7. The battery pole piece of claim 6, wherein, the number of the accommodation grooves located in the middle of the corner region is greater than the number of the accommodation grooves located on at least one side edge of the corner region in the first direction.
8. The battery pole piece of claim 1, wherein, the current collector has a plurality of through holes corresponding to positions of the corner regions.
9. The battery pole piece of claim 8, wherein, the through holes have a wave-shaped cross section.
10. The battery pole piece of claim 1, wherein, the graphite layers comprise a first graphite layer and a second graphite layer arranged in sequence along the second direction, the first graphite layer is located between the current collector and the second graphite layer, and the chamfers are arranged on the second graphite layer.
11. A battery, characterized by the application further relates to a battery pole piece comprising any one of the battery pole pieces as claimed in claims 1 to 10.