Battery cell structure and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell structure and a battery. The cell structure comprises an anode plate and a cathode plate, the anode plate comprises an anode foil and a plurality of anode lugs, the anode lugs and the anode foil are connected into an integrated structure, and the anode lugs are stacked in the thickness direction of the cell structure; the cathode piece comprises a cathode foil piece, a cathode lug and a dressing layer, the cathode lug is welded with the cathode foil piece, and the dressing layer is arranged on at least one side of the cathode foil piece in the thickness direction; and the width of the dressing layer is equal to that of the cathode foil. According to the battery cell structure disclosed by the utility model, the energy density of the battery can be improved while most of the quick charging performance of the battery is kept, and the occupation of the tabs on the internal space of the battery is reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cell structure and a battery. Background Technology

[0002] Charging speed and energy density are important indicators of battery performance. Currently, multi-tab structures are commonly used to provide more electron transport channels to reduce internal resistance and thus improve charging speed. The conventional approach for multi-tab batteries is to die-cut multiple anode tabs on the anode foil of the cell structure to form the battery anode, and to die-cut multiple cathode tabs on the cathode foil of the cell structure to form the battery cathode. However, this type of battery has the following technical problems that affect its energy density:

[0003] 1. An insulating layer needs to be set at the edge of the cathode foil to facilitate die-cutting, which reduces the area of ​​the cathode foil that can be covered with coating;

[0004] 2. The die-cut tabs are prone to wrinkles or breakage during the roll forming process. Therefore, it is necessary to sample thicker foils and reduce the pressure applied during the roll forming process, which results in thinner dressings and lower compaction density.

[0005] 3. Multiple anode lugs and multiple cathode lugs occupy space inside the battery after winding, resulting in low space utilization inside the battery. Utility Model Content

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a cell structure that can improve the energy density of the battery while retaining its fast-charging capability.

[0007] This utility model also proposes a battery having the above-mentioned cell structure.

[0008] The battery cell structure according to the first aspect of the present invention includes:

[0009] An anode sheet, comprising an anode foil and a plurality of anode lugs, wherein each anode lug is connected to the anode foil as an integral structure, and each anode lug is stacked along the thickness direction of the cell structure;

[0010] A cathode sheet, comprising a cathode foil, cathode lugs, and a dressing layer, wherein the cathode lugs are welded to the cathode foil, and the dressing layer is disposed on at least one side of the cathode foil in the thickness direction; the width of the dressing layer is equal to the width of the cathode foil.

[0011] The battery cell structure according to the embodiments of this utility model has at least the following beneficial effects:

[0012] By using multiple anode tabs integrally formed with the anode foil on the anode sheet, most of the battery's fast-charging performance can be retained. Welding the cathode tabs to the cathode foil eliminates the need for the insulating layer reserved for cutting the cathode tabs on the cathode foil, allowing the width of the coating area to match the width of the cathode foil, increasing the coating layer area and improving the battery's energy density. Welded cathode tabs are thicker than die-cut cathode tabs, thus preventing wrinkles or breakage during the rolling process in battery manufacturing. This allows for greater pressure during rolling, and the cathode foil can be made of thinner material, resulting in greater compaction density of the coating layer on the cathode foil, further improving the battery's energy density. The number of welded cathode tabs is typically less than that of die-cut cathode tabs, reducing the space occupied by the tabs within the battery.

[0013] According to some embodiments of the present invention, along the thickness direction of the cell structure, the projection of the cathode lug is located outside the projection of the anode lug.

[0014] According to some embodiments of the present invention, two cathode ears are provided, namely a first cathode ear and a second cathode ear;

[0015] Along the thickness direction of the cell structure, the projection of the anode lug is located between the projection of the first cathode lug and the projection of the second cathode lug.

[0016] According to some embodiments of the present invention, two cathode ears are provided, namely a first cathode ear and a second cathode ear;

[0017] Along the thickness direction of the cell structure, the projections of the first cathode lug and the second cathode lug are located on the same side as the projection of the anode lug, and the projection of the first cathode lug is located between the projections of the anode lug and the second cathode lug; the distance between the projections of the first cathode lug and the second cathode lug is less than the distance between the projections of the first cathode lug and the anode lug.

[0018] According to some embodiments of the present invention, the cathode lug includes a welding portion and an extension portion, wherein the welding portion is welded to the cathode foil, and the extension portion extends out of the cathode foil;

[0019] The dressing layer has a groove; along the thickness direction of the cell structure, the projection of the welded part is within the projection of the groove.

[0020] According to some embodiments of the present invention, the width of the cathode lug is W1, and the width of the groove is W2, wherein W1≤W2≤1.5W1.

[0021] According to some embodiments of the present invention, the thickness of the cathode lug is T1, and the depth of the groove is T2, wherein 0.3T1≤T2≤2T1.

[0022] According to some embodiments of the present invention, the dressing layer is provided with a cleaning area, and the cathode lug is welded to the cleaning area.

[0023] According to some embodiments of the present invention, two cathode ears are provided, namely a first cathode ear and a second cathode ear;

[0024] One end of the cathode sheet along its length is provided with an empty foil area, the first cathode lug is welded to the empty foil area, and the second cathode lug is welded to the cleaning area.

[0025] According to some embodiments of this utility model, two cathode ears are provided, and empty foil areas are provided at both ends of the cathode sheet in the length direction. The two cathode ears are respectively welded to the two empty foil areas.

[0026] The battery according to a second aspect embodiment of the present invention includes the cell structure described above. The battery of this embodiment simultaneously possesses excellent fast-charging performance and energy density; since the battery of this embodiment includes the cell structure described above, it also possesses at least all the beneficial effects of the cell structure, which will not be elaborated upon here.

[0027] 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

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 This is a front view of one embodiment of the battery cell structure according to the first aspect of the present invention;

[0030] Figure 2 This is a front view of another embodiment of the cell structure according to the first aspect of this utility model;

[0031] Figure 3 for Figure 1 A schematic diagram of the first welding position for welding the cathode lug of the battery cell structure to the cathode foil;

[0032] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0033] Figure 5 for Figure 1 A schematic diagram of the second welding position of the cathode lug of the battery cell structure to the cathode foil.

[0034] Icon labels:

[0035] Anode plate 100, anode foil 110, anode lug 120;

[0036] Cathode sheet 200, cathode foil 210, cathode lug 220, welding part 221, extension part 222, dressing layer 230, groove 231, empty foil area 240. Detailed Implementation

[0037] 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.

[0038] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, etc., indicating the directional or positional relationship, are based on the directional or positional relationship shown in the drawings and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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.

[0039] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features or their sequential relationship.

[0040] 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.

[0041] Reference Figures 1 to 5 The battery cell structure of the first aspect of this utility model includes an anode sheet 100 and a cathode sheet 200. The anode sheet 100 includes an anode foil 110 and a plurality of anode lugs 120, each anode lug 120 being connected to the anode foil 110 as an integral structure, and each anode lug 120 being stacked along the thickness direction of the battery cell structure. The cathode sheet 200 includes a cathode foil 210, cathode lugs 220, and a coating layer 230, the cathode lugs 220 being welded to the cathode foil 210, and the coating layer 230 being disposed on at least one side of the cathode foil 210 in the thickness direction; the width of the coating layer 230 is equal to the width of the cathode foil 210. Specifically, refer to... Figure 1As shown, the anode ear 120 is connected to the anode foil 110 as an integral structure. That is, the anode ear 120 is obtained by die-cutting the anode foil 110. Therefore, the material and thickness of the anode ear 120 are the same as those of the anode foil 110. The anode sheet 100 has multiple anode ears 120 integrally formed with the anode foil 110, which can retain most of the fast charging performance of the battery.

[0042] Furthermore, the welding method between the cathode tab 220 and the cathode foil 210 is not limited in this embodiment, and a suitable welding method can be selected according to the actual situation. Welding the cathode tab 220 to the cathode foil 210 can eliminate the insulating layer reserved on the cathode foil 210 for cutting the cathode tab 220, so that the width of the dressing layer 230 is consistent with the width of the cathode foil 210, thereby increasing the area of ​​the dressing layer 230 and improving the energy density of the battery. The welded cathode tab 220 is thicker than the die-cut cathode tab 220. The increase in the thickness of the cathode tab 220 can prevent wrinkles or breakage of the cathode tab 220 during the rolling step of battery processing. The rolling step can use a greater pressure to increase the compaction density of the dressing layer 230 on the cathode foil 210. The cathode foil 210 can also use a thinner material, thereby improving the energy density of the battery. The number of welded cathode tabs 220 is usually less than the number of die-cut cathode tabs 220, thereby reducing the space occupied by the tabs in the battery.

[0043] In the embodiments of this utility model, along the thickness direction of the cell structure, the projection of the cathode ear 220 is located outside the projection of the anode ear 120. That is, the projection of the cathode ear 220 in the thickness direction of the cell structure does not intersect with the projection of the anode ear 120 in the thickness direction of the cell structure. This can avoid the cathode ear 220 and the anode ear 120 from contacting each other and causing short circuit damage to the cell structure. Even if the projection of the cathode ear 220 in the thickness direction of the cell structure intersects with the projection of the anode ear 120 in the thickness direction of the cell structure, it can still lead to an increase in the thickness of the cell structure or uneven thickness of the cell structure, affecting the quality of the cell structure.

[0044] In this embodiment of the invention, the cathode sheet 200 includes a plurality of cathode tabs 220, preferably two cathode tabs 220. The number of cathode tabs 220 simultaneously affects the charging speed and energy density of the battery. The charging speed of the battery increases with the increase of the number of cathode tabs 220, but the increase of the number of cathode tabs 220 also leads to a reduction in the area of ​​the coating layer 230, so the energy density of the battery decreases with the increase of the number of cathode tabs 220. The charging speed of the battery does not increase linearly with the increase of the number of cathode tabs 220, but the energy density of the battery is actually lost with the increase of the number of cathode tabs 220. The anode sheet 100 of the cell structure in this embodiment has a plurality of anode tabs 120, so the battery including the cell structure of this embodiment has a certain fast charging capability. Tests have shown that welding two cathode tabs 220 to the cathode sheet 200 can better balance the charging speed and energy density of the battery.

[0045] In embodiments of this utility model, along the thickness direction of the battery cell structure, the projections of the two cathode lugs 220 are both located outside the projection of the anode lug 120. The projections of the two cathode lugs 220 may intersect or not, and this embodiment is not limited thereto. When the projections of the two cathode lugs 220 do not intersect along the thickness direction of the battery cell structure, there are two possible technical solutions:

[0046] In one embodiment, reference is made to... Figure 1 As shown, along the thickness direction of the cell structure, the projections of the two cathode lugs 220 can be located on both sides of the projection of the anode lug 120, that is, the projection of the anode lug 120 is located between the projections of the two cathode lugs 220.

[0047] In another embodiment, refer to Figure 2 As shown, along the thickness direction of the cell structure, the projections of the two cathode lugs 220 can be located on the same side as the projection of the anode lug 120.

[0048] The specific arrangement can be flexibly set according to the specific arrangement of the batteries and their actual use.

[0049] It is important to note that, in Figure 2 In the embodiment shown, the two cathode ears 220 are defined as the first cathode ear and the second cathode ear, respectively. If the projection of the first cathode ear is located between the projection of the anode ear 120 and the projection of the second cathode ear along the thickness direction of the cell structure, it is preferable that the distance between the projection of the first cathode ear and the projection of the second cathode ear is smaller than the distance between the projection of the first cathode ear and the projection of the anode ear, so as to reduce the risk of short circuit when the anode ear 120 contacts the first cathode ear.

[0050] In embodiments of this invention, the cathode ear 220 may be welded to the middle of the dressing layer 230 or to both ends of the dressing layer 230; see reference. Figure 3 As shown, the dressing layer 230 has a cleaning area for welding cathode ears 220. The cleaning area is located on at least one side of the width direction of the dressing layer 230. The cleaning area can be located in the middle or at both ends of the dressing layer 230. The number of cathode ears 220 is equal to the number of cleaning areas, that is, each cleaning area is welded with cathode ears 220. Specifically, as mentioned above, there are preferably two cathode ears 220. Therefore, the dressing layer 230 has two cleaning areas. The two cleaning areas are preferably located at one-third and two-thirds of the length direction of the dressing layer 230 or at both ends of the length direction of the dressing layer 230. That is, the two cathode ears 220 are preferably welded at one-third and two-thirds of the length direction of the dressing layer 230 or at both ends of the length direction of the dressing layer 230 to ensure that the charging and discharging performance of the two cathode ears 220 is consistent.

[0051] It is conceivable that, since the cleaning zone is located in the dressing layer 230, the length of the dressing layer 230 can be set to be equal to the length of the cathode foil 210.

[0052] In embodiments of this invention, if the length of the dressing layer 230 on at least one side of the cathode foil 210 in the thickness direction is less than the length of the cathode foil 210, a hollow foil area 240 will be formed on at least one side of the cathode foil 210 in the thickness direction. Preferably, the hollow foil area 240 is located at the end of the cathode foil 210 in the length direction to reduce processing difficulty and thus reduce processing costs. Specifically, if the cathode foil 210 has a hollow foil area 240 formed only at one end in the length direction or both ends in the length direction of the cathode foil 210, then the cathode ear 220 in this embodiment can be welded to the cathode foil 210 using the following method:

[0053] Taking the cathode foil 210 of this embodiment as having two cathode lugs 220 welded on, for ease of understanding, the two cathode lugs 220 are defined as the first cathode lug and the second cathode lug, respectively;

[0054] Option 1: If the cathode foil 210 has an empty foil area 240 at only one end in the length direction, then the first cathode lug can be welded to the empty foil area 240 and the second cathode lug can be welded to the cleaning area of ​​the dressing layer 230.

[0055] Option 2: If both ends of the cathode foil 210 along its length have empty foil areas 240, then the first cathode lug and the second cathode lug can be welded to the two empty foil areas 240 respectively.

[0056] It is important to understand that the scheme of leaving an empty foil area 240 at at least one end of the cathode foil 210 in the length direction for welding the cathode lug 220 eliminates the need to clean the dressing layer 230, resulting in fewer processing steps and lower manufacturing costs.

[0057] Furthermore, in Scheme 2, if both the first cathode ear and the second cathode ear are attached to both ends of the dressing layer 230 along its length, then the widths of the first cathode ear and the second cathode ear are preferably the same; if both the first cathode ear and the second cathode ear have a gap with both ends of the dressing layer 230 along its length, then the widths of the first cathode ear and the second cathode ear can be adjusted accordingly based on the gap between the cathode ear 220 and the dressing layer 230; for example, referring to... Figure 5 As shown, let the distance between the first cathode lug and the dressing layer 230 be S1, the distance between the second cathode lug and the dressing layer 230 be S2, and the width of the first cathode lug be W. 11 The width of the second cathode ear is W 12 Where, if S1 > S2, then W 11 <W 12 This is to balance the charging and discharging performance of the first and second cathode ears. Correspondingly, if S1 < S2, then W 11 >W 12 If S1 = S2, then W 11 =W 12 .

[0058] In an embodiment of this utility model, the cathode ear 220 includes a welding portion 221 and an extension portion 222. The welding portion 221 is welded to the cathode foil 210, and the extension portion 222 extends out of the cathode foil 210. The coating layer 230 is provided with a groove 231. Along the thickness direction of the cell structure, the groove 231 is disposed on the coating layer 230 adjacent to the cathode ear 220, and the projection of the welding portion 221 is within the projection of the groove 231. Specifically, refer to... Figure 1 As shown, along the thickness direction of the cell structure, the welding portion 221 is located within the projection of the cathode foil 210, and the extension portion 222 is located outside the projection of the cathode foil 210. (Refer to...) Figure 3 , Figure 4 As shown, the depth of the groove 231 is less than the depth of the coating layer 230. Aligning the groove 231 with the welded portion 221 along the thickness direction of the cell structure improves the flatness of the cell structure. The cathode tab 220, as a welded tab, protrudes from the surface of the cathode foil 210. Consequently, in the thickness direction of the cell structure, the position where the cathode tab 220 is welded will be slightly higher than other parts. Aligning the groove 231 with the cathode tab 220 on the coating layer 230 makes the cell structure flatter in the thickness direction, thereby improving the safety and aesthetics of the battery.

[0059] It is important to understand that if there are two cathode ears 220, then there are at least two grooves 231. That is, along the thickness direction of the cell structure, each cathode ear 220 has at least one groove 231 aligned with it. For ease of understanding, in this embodiment, the two cathode ears 220 are also designated as the first cathode ear and the second cathode ear, respectively. Along the thickness direction of the cell structure, the first cathode ear may have only one groove 231 aligned with it, and the second cathode ear may have only one groove 231 aligned with it; or the first cathode ear may have only one groove 231 aligned with it, and the second cathode ear may have multiple grooves 231 aligned with it; or the first cathode ear may have multiple grooves 231 aligned with it, and the second cathode ear may have only one groove 231 aligned with it; or the first cathode ear may have multiple grooves 231 aligned with it, and the second cathode ear may have multiple grooves 231 aligned with it. The specific number of grooves 231 can be flexibly set according to the actual situation.

[0060] In an embodiment of this invention, the thickness of the cathode lug 220 is T1, and the depth of the groove 231 is T2, wherein 0.3T1≤T2≤2T1. Specifically, refer to... Figure 4 As shown, the depth of the groove 231 should be less than the thickness of the dressing layer 230. As can be seen from the above, along the thickness direction of the cell structure, there are multiple grooves 231 aligned with both the first and second cathode ears. If only one first groove 231 is aligned with the first cathode ear in the thickness direction of the cell structure, the depth of the first groove 231 is preferably 0.3T1 to T1. If multiple first grooves 231 are aligned with the first cathode ear in the thickness direction of the cell structure, the sum of the depths of the multiple first grooves 231 aligned with the first cathode ear is preferably 0.3T1 to T1. Similarly, if only one second groove 231 is aligned with the second cathode ear in the thickness direction of the cell structure, the depth of the second groove 231 is preferably 0.3T1 to T1. If multiple second grooves 231 are aligned with the second cathode ear in the thickness direction of the cell structure, the sum of the depths of the multiple second grooves 231 aligned with the second cathode ear is preferably 0.3T1 to T1.

[0061] In an embodiment of this utility model, the width of the cathode lug 220 is W1, and the width of the groove 231 is W2, wherein W1 ≤ W2 ≤ 1.5W1. Specifically, refer to... Figure 4 As shown, the width of the groove 231 is preferably equal to the width of the cathode lug 220. However, there may be errors in the actual processing of the cell structure. Setting the width of the groove 231 to be slightly larger than the width of the cathode lug 220 can ensure that the projection of the welding part 221 of the cathode lug 220 is always within the projection of the groove 231 along the thickness direction of the cell structure. The width of the groove 231 should not exceed the width of the cathode lug 220 by too much. If the width of the groove 231 is too large, it will also lead to a decrease in the energy density of the battery.

[0062] The battery of the second aspect of this utility model includes the cell structure described above. The battery of this embodiment simultaneously possesses excellent fast-charging performance and energy density; since the battery of this embodiment includes the cell structure described above, it also possesses at least all the beneficial effects of the cell structure, which will not be elaborated upon here.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0064] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A battery cell structure, characterized in that, include: An anode sheet, comprising an anode foil and a plurality of anode lugs, wherein each anode lug is connected to the anode foil as an integral structure, and each anode lug is stacked along the thickness direction of the cell structure; A cathode sheet, comprising a cathode foil, cathode lugs, and a dressing layer, wherein the cathode lugs are welded to the cathode foil, and the dressing layer is disposed on at least one side of the cathode foil in the thickness direction; the width of the dressing layer is equal to the width of the cathode foil.

2. The cell structure according to claim 1, characterized in that: Along the thickness direction of the cell structure, the projection of the cathode lug is outside the projection of the anode lug.

3. The cell structure according to claim 2, characterized in that: The cathode lugs are provided in two forms, namely the first cathode lug and the second cathode lug. Along the thickness direction of the cell structure, the projection of the anode lug is located between the projection of the first cathode lug and the projection of the second cathode lug.

4. The cell structure according to claim 2, characterized in that: The cathode lugs are provided in two forms, namely the first cathode lug and the second cathode lug. Along the thickness direction of the cell structure, the projections of the first cathode lug and the second cathode lug are located on the same side as the projection of the anode lug, and the projection of the first cathode lug is located between the projections of the anode lug and the second cathode lug; the distance between the projections of the first cathode lug and the second cathode lug is less than the distance between the projections of the first cathode lug and the anode lug.

5. The cell structure according to claim 1, characterized in that: The cathode lug includes a welding portion and an extension portion, the welding portion being welded to the cathode foil, and the extension portion extending out of the cathode foil; The dressing layer has a groove; along the thickness direction of the cell structure, the projection of the welded part is within the projection of the groove.

6. The cell structure according to claim 5, characterized in that: The width of the cathode lug is W1, and the width of the groove is W2, wherein W1≤W2≤1.5W1.

7. The cell structure according to claim 5, characterized in that: The thickness of the cathode lug is T1, and the depth of the groove is T2, wherein 0.3T1≤T2≤2T1.

8. The cell structure according to claim 1, characterized in that: The dressing layer has a cleaning zone, and the cathode lug is welded to the cleaning zone.

9. The cell structure according to claim 8, characterized in that: The cathode lugs are provided in two forms, namely the first cathode lug and the second cathode lug. One end of the cathode sheet along its length is provided with an empty foil area, the first cathode lug is welded to the empty foil area, and the second cathode lug is welded to the cleaning area.

10. The cell structure according to claim 1, characterized in that: The cathode lugs are provided in two places, and empty foil areas are provided at both ends of the cathode sheet along its length. The two cathode lugs are respectively welded to the two empty foil areas.

11. A battery, characterized in that: Includes the cell structure described in any one of claims 1 to 10.

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