Battery cell and battery

Abstract

The utility model discloses a kind of electric core and battery, wherein, electric core includes pole piece, diaphragm and true tab, multiple pole piece is laminated, the polarity of adjacent two pole pieces is opposite, and diaphragm is equipped between adjacent two pole pieces;Multiple pole pieces with same polarity include first pole piece and second pole piece, first pole piece has empty foil area, part structure of true tab is between first pole piece and adjacent diaphragm, true tab is connected with empty foil area, second pole piece has protruding false tab, and false tab is conductive connection with part structure of true tab exposed to first pole piece.The electric core of the utility model can integrate true tab to pole piece interlayer, realize fixed using pole piece itself structure, reduce invalid space.When external packaging force acts on true tab, force is conducted to the current collector of first pole piece by empty foil area, is dispersed and absorbed by entire pole piece structure, reduce the mechanical load of false tab and true tab welding point, to effectively avoid mechanical damage of welding position in packaging process.

Description

Technical Field

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

[0002] In related technologies, to improve the energy density of lithium-ion batteries, a common approach is to weld the dummy tabs of the electrode sheets to the outer tabs. In practice, the outer tabs need to extend into the packaging shell but must maintain a safe distance from the separator, electrode sheets, etc., resulting in some wasted space. Furthermore, after welding the outer tabs to the dummy tabs, the outer tabs, under stress during or after packaging, can easily pull the dummy tabs along the welding point, posing a risk of mechanical wear. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell capable of...

[0004] This utility model also proposes a battery having the above-mentioned battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, including electrodes, a separator, and a true electrode tab, wherein a plurality of electrodes are stacked, adjacent electrodes have opposite polarities, and the separator is provided between adjacent electrodes;

[0006] The plurality of electrodes of the same polarity include a first electrode and a second electrode. The first electrode has an empty foil area. A portion of the structure of the true electrode tab is located between the first electrode and the adjacent diaphragm. The true electrode tab is connected to the empty foil area. The second electrode has a protruding dummy electrode tab. The dummy electrode tab is electrically connected to the portion of the true electrode tab exposed on the first electrode.

[0007] The battery cell according to the embodiments of this utility model has at least the following beneficial effects: In the stacked structure, the empty foil area of ​​the first electrode sheet forms a physical connection with the true electrode tab, integrating the true electrode tab into the electrode sheet layer, and directly utilizing the electrode sheet's own structure for fixation, effectively reducing ineffective space. The dummy electrode tab of the second electrode sheet extends outward and contacts and conducts with the exposed portion of the true electrode tab. When external encapsulation force is applied to the true electrode tab, the force is conducted to the current collector of the first electrode sheet through the empty foil area, and is dispersed and absorbed by the entire electrode sheet structure, reducing the mechanical load at the solder joint between the dummy electrode tab and the true electrode tab, thereby effectively avoiding mechanical damage to the solder joint during the encapsulation process.

[0008] According to the first aspect, in one possible implementation, the battery cell further includes a package, the package including a first package portion and a second package portion, the first package portion having an inner cavity, the electrode and the separator being packaged in the inner cavity; the second package portion having a channel communicating with the inner cavity, the second package portion covering the connection between the dummy electrode and the real electrode, and a portion of the real electrode passing through the channel.

[0009] According to the first aspect, in one possible implementation, the dummy tab and the true tab have an overlapping structure along the stacking direction, the second encapsulation portion at least covers part of the overlapping structure, and tab adhesive is filled between the second encapsulation portion and the overlapping structure.

[0010] According to the first aspect, in one possible implementation, the diaphragm has a first edge, the dummy tab protrudes from the first edge, and the distance between the first encapsulation portion and the first edge is 0 to 1 mm.

[0011] According to the first aspect, in one possible implementation, the first electrode includes a first current collector and a first active layer disposed on one side of the first current collector, the first active layer forming a receiving groove to expose the empty foil area;

[0012] The battery cell also includes a protective adhesive, which is disposed on the side of the first active layer away from the first current collector, and the protective adhesive covers the projection area of ​​the receiving groove in the first current collector.

[0013] According to the first aspect, in one possible implementation, the first electrode further includes a second active layer disposed on the side of the first current collector opposite to the first active layer, the second active layer covering the empty foil area along the thickness stacking direction; and / or,

[0014] The electrode adjacent to the first electrode and located on the side where the true electrode tab is located includes a second current collector and a third active layer disposed on one side of the second current collector. The third active layer has a thinning region. The thinning region is disposed opposite to the empty foil region, and the thinning region covers the projection region of the receiving groove on the first current collector in the projection region of the first current collector.

[0015] According to the first aspect, in one possible implementation, the empty foil area includes a first area and a second area arranged sequentially along the protruding direction of the dummy electrode tab, wherein the width of the first area is greater than the width of the second area;

[0016] The true electrode tab includes a first electrode tab portion and a second electrode tab portion connected together. The width of the first electrode tab portion is greater than the width of the second electrode tab portion. The first electrode tab portion is connected to the first region, a portion of the second electrode tab portion is connected to the second region, and the remaining portion of the second electrode tab portion is exposed at the edge of the first electrode plate.

[0017] According to the first aspect, in one possible implementation, the size of the true electrode is larger than the size of the dummy electrode in a direction perpendicular to the protruding direction of the dummy electrode, and the vertical projection of the true electrode onto the plane containing the dummy electrode completely covers the dummy electrode.

[0018] According to the first aspect, in one possible implementation, the plurality of electrodes include a plurality of positive electrodes and a plurality of negative electrodes; the size of the positive electrodes is smaller than the size of the negative electrodes; and / or,

[0019] The positive electrode includes a main body and a dummy electrode tab. The main body has a second edge, and the dummy electrode tab protrudes from the second edge. An insulating layer is provided on the portion of the main body near the second edge.

[0020] Secondly, embodiments of this application also provide a battery, the battery comprising the cell described in the first aspect.

[0021] The battery according to the embodiments of this utility model has at least the following beneficial effects: By applying the above-mentioned battery cell, the empty foil area of ​​the first electrode sheet is physically connected to the true electrode tab, integrating the true electrode tab into the electrode sheet layer, and directly utilizing the electrode sheet's own structure for fixation, effectively reducing ineffective space. The dummy electrode tab of the second electrode sheet extends outward and contacts and conducts with the exposed portion of the true electrode tab. When external encapsulation force is applied to the true electrode tab, the force is conducted through the empty foil area to the current collector of the first electrode sheet, and is dispersed and absorbed by the entire electrode sheet structure, reducing the mechanical load at the solder joint between the dummy electrode tab and the true electrode tab, thereby effectively avoiding mechanical damage to the solder joint during the encapsulation process.

[0022] 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

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0024] Figure 1 This is a schematic diagram of the battery cell structure in an embodiment of this utility model;

[0025] Figure 2 This is a partial disassembly diagram of the battery cell in an embodiment of this utility model;

[0026] Figure 3This is a schematic diagram of the connection structure between the true electrode tab and the first electrode plate in an embodiment of this utility model;

[0027] Figure 4 This is a schematic diagram of the connection structure between the true electrode and the false electrode in an embodiment of this utility model;

[0028] Figure 5 This is a schematic diagram of the internal structure of the package in an embodiment of the present utility model;

[0029] Figure 6 This is a schematic diagram of the stacked structure of the battery cell in an embodiment of this utility model;

[0030] Figure 7 This is a schematic diagram of the cooperation structure between the first electrode and the adjacent electrode in an embodiment of this utility model;

[0031] Figure 8 This is a schematic diagram of the structure of the positive electrode in an embodiment of this utility model.

[0032] Figure label:

[0033] 100. Battery cells;

[0034] 110, Electrode; 110a, Positive Electrode; 110b, Negative Electrode; 111, First Electrode; 1111, Empty Foil Region; 11111, First Region; 11112, Second Region; 1112, First Current Collector; 1113, First Active Layer; 1114, Receiving Tank; 1115, Second Active Layer; 112, Second Electrode; 1121, Dummy Tab; 1131, Main Body; 1132, Second Edge; 1133, Insulating Layer; 1141, Second Current Collector; 1142, Third Active Layer; 1143, Thinning Region;

[0035] 120. Diaphragm; 121. First edge;

[0036] 130. True pole ear; 131. First pole ear portion; 132. Second pole ear portion;

[0037] 140. Package; 141. First package; 1411. Inner cavity; 142. Second package; 1421. Channel;

[0038] 151. Overlapping structure; 152. Tab adhesive;

[0039] 160. Protective adhesive. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] 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. The use of "first" and "second" in the description is merely for 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.

[0043] 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.

[0044] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. 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.

[0045] In related technologies, to improve the energy density of lithium-ion batteries, a common approach is to weld the dummy tabs of the electrode sheets to the outer tabs. In practice, the outer tabs need to extend into the packaging shell but must maintain a safe distance from the separator, electrode sheets, etc., resulting in some wasted space. Furthermore, after welding the outer tabs to the dummy tabs, the outer tabs, under stress during or after packaging, can easily pull the dummy tabs along the welding point, posing a risk of mechanical wear.

[0046] To address the aforementioned problems, this application proposes a battery cell, in some embodiments, such as... Figures 1 to 3 As shown, the battery cell 100 includes electrode sheets 110, separators 120, and true tabs 130. Multiple electrode sheets 110 are stacked and arranged with alternating polarities, and separators 120 are disposed between adjacent electrode sheets 110. Electrode sheets of the same polarity include a first electrode sheet 111 and a second electrode sheet 112. The first electrode sheet 111 has an empty foil area 1111. The true tab 130 is partially located between the electrode sheet 110 and the adjacent separator 120 and is connected to the empty foil area 1111. The second electrode sheet 112 has a protruding dummy tab 1121, which is electrically connected to the exposed portion of the true tab 130.

[0047] The electrode 110 is a stacked arrangement of positive and negative electrodes, forming the main structure of the cell 100. Aluminum foil or copper foil can be used as the current collector substrate. The separator 120 is an insulating layer, specifically a polyethylene or polypropylene microporous membrane for electrical isolation between the electrodes 110. The true tab 130 is a structural component directly connecting to the external circuitry of the battery, specifically made of nickel or aluminum strip, partially embedded between the electrode 110 and the separator 120 for fixation. The empty foil area 1111 is the exposed area of ​​the current collector of the electrode 110 without active material coating, formed by scraping, laser cleaning, or mask coating processes, used to establish a conductive connection between the true tab 130 and the current collector. The dummy tab 1121 is a conductive structure extending from the edge of the electrode 110, formed by die-cutting the electrode 110 to establish surface contact with the true tab 130.

[0048] Specifically, in the stacked structure, the empty foil area 1111 of the first electrode 111 is physically connected to the true electrode tab 130, integrating the true electrode tab 130 into the interlayer of the electrode 110. Fixation is achieved directly using the structure of the electrode 110 itself, effectively reducing unused space. The dummy electrode tab 1121 of the second electrode 112 extends outward and forms surface contact with the exposed portion of the true electrode tab 130. The contact area can be electrically connected via ultrasonic welding or laser welding. When external encapsulation force is applied to the true electrode tab 130, the force is conducted through the empty foil area 1111 to the current collector of the first electrode 111, and is dispersed and absorbed by the entire electrode structure, reducing the mechanical load at the solder joint between the dummy electrode tab 1121 and the true electrode tab 130, thereby effectively avoiding mechanical damage to the solder joint during the encapsulation process.

[0049] In some embodiments, such as Figure 1 , Figure 4 and Figure 5The shown battery cell 100 also includes a package 140, which includes a first package portion 141 and a second package portion 142. The first package portion 141 is a shell structure for packaging the electrode 110 and the separator 120. The first package portion 141 has an inner cavity 1411 and can completely enclose the stacked electrode 110 and separator 120 to form a sealed space. The second package portion 142 is an auxiliary packaging structure connected to the outer edge of the first package portion 141. Specifically, it can be implemented by using an extended covering structure of the same material as the first package portion 141. The second package portion 142 has a channel 1421 communicating with the inner cavity 1411. The second package portion 142 covers the connection between the dummy electrode 1121 and the true electrode 130, and part of the true electrode 130 passes through the channel 1421. The second package portion 142 allows part of the structure of the true electrode 130 to protrude while maintaining the integrity of the package.

[0050] The first encapsulation part 141 encapsulates multiple stacked electrode sheets 110 and separator 120 to form the main body of the battery cell. The second encapsulation part 142 extends to the edge region of the battery cell 100 to form a covering structure. The connection between the dummy tab 1121 and the true tab 130 in the stacking direction of the electrode sheets 110 is encapsulated by the second encapsulation part 142, and the extended end of the true tab 130 is led outward through the channel 1421. This dual encapsulation structure allows the tab connection point and the main body of the electrode sheet 110 to be encapsulated in separate areas. The electrode sheet 110 arrangement space in the inner cavity 1411 and the tab lead-out path form independent areas that do not interfere with each other, effectively compressing the redundant space required by traditional external tabs.

[0051] The first packaging section 141 and the second packaging section 142 can be implemented using an integrated aluminum-plastic film, and this application does not limit this.

[0052] Based on the above embodiments, the dummy tab 1121 and the true tab 130 have an overlapping structure 151 along the stacking direction. The second encapsulation portion 142 at least covers a portion of the overlapping structure 151, and tab adhesive 152 fills the space between the second encapsulation portion 142 and the overlapping structure 151. The overlapping structure 151 refers to a portion of the dummy tab 1121 and the true tab 130 overlapping each other in a direction perpendicular to the stacking direction of the electrode sheet 110, which can be achieved by welding or riveting. The second encapsulation portion 142 provides physical support for the connection and isolates it from the external environment. Tab adhesive 152 refers to a viscoelastic material filled between the second encapsulation portion and the overlapping structure 151, which can be silicone or epoxy resin, and is achieved by coating or injection, used to absorb mechanical vibration and block electrolyte penetration.

[0053] The dummy tab 1121 and the true tab 130 form a stable mechanical connection base through the overlapping structure 151 in the stacking direction. The second encapsulation part 142 partially covers the overlapping area, ensuring encapsulation integrity while avoiding increasing the volume of the cell 100. The tab adhesive 152 is filled in the gap between the second encapsulation part 142 and the overlapping structure 151. When the cell 100 is subjected to external impact or vibration, this material absorbs energy through deformation, reducing the shear force on the welding part. In addition, the cooperation between the tab adhesive 152 and the second encapsulation part 142 forms a double sealing barrier, effectively preventing the electrolyte from spreading outward along the tab connection path.

[0054] Furthermore, the separator 120 has a first edge 121, and the dummy tab 1121 protrudes from the first edge 121. The first edge 121 of the separator 120 refers to the end boundary line of the separator 120 in the stacking direction, which can be achieved by forming a flat cut surface through a punching process. The first edge 121 provides a positioning reference for the package 140. The dummy tab 1121 protruding from the first edge 121 means that the extension length of the dummy tab 1121 in the stacking direction exceeds the end boundary line of the separator 120. The distance between the first package portion 141 and the first edge 121 refers to the gap between the inner wall of the package structure and the end of the separator 120. The gap between the inner wall of the first package portion 141 and the end of the separator 120 is controlled within the range of 0 to 1 mm, for example, it can be 0.5 mm. In this case, the first package portion 141 tightly wraps the electrode group 110 along the edge of the separator 120, which can eliminate the spatial redundancy of the traditional reserved safety distance to the maximum extent and improve the energy density of the cell 100.

[0055] Specifically, the tab adhesive 152 can protrude 0.2mm to 2.0mm from the edge of the second encapsulation portion 142. The width of the inner cavity 1411 of the first encapsulation portion 141 is 0 to 0.2mm wider than the width of the bare cell structure composed of the electrode 110 and the separator 120. This minimizes the gap between the first encapsulation portion 141 and the bare cell 100 structure, thereby increasing the energy density of the cell 100. The length of the dummy tab 1121 extending beyond the first edge 121 of the separator 120 is designed to be more than 2mm, thereby ensuring the effective welding area between the dummy tab 1121 and the true tab 130 and ensuring the connection stability between the dummy tab 1121 and the true tab 130.

[0056] In some embodiments, such as Figure 1 , Figure 6 and Figure 7As shown, the first electrode 111 includes a first current collector 1112 and a first active layer 1113 disposed on one side of the first current collector 1112. The first active layer 1113 forms a receiving groove 1114 to expose the empty foil area 1111. The cell 100 also includes a protective adhesive 160, which is disposed on the side of the first active layer 1113 away from the first current collector 1112. The protective adhesive 160 covers the receiving groove 1114 in the projection area of ​​the first current collector 1112.

[0057] The first current collector 1112 refers to the metal foil substrate carrying the active material, which can be made of aluminum foil or copper foil, and is used to conduct current and provide mechanical support. The first active layer 1113 refers to the electrochemical active material layer coated on the surface of the first current collector 1112, which can be made of lithium-ion battery positive or negative electrode material. The receiving groove 1114 refers to the recessed area formed by removing material in the first active layer 1113, which can be achieved by scraping with a scraper or laser cleaning process. Its function is to provide insertion space for the electrode tab 130 and ensure connection reliability. The empty foil area 1111 refers to the part of the first current collector 1112 that is not covered by the active material, which is formed by removing the first active layer 1113, and is used to directly contact the electrode tab 130 to achieve conductive connection. The protective adhesive 160 refers to the insulating material layer covering the surface of the first active layer 1113. Specifically, it can be made of polyimide adhesive or epoxy resin adhesive. It is set by coating or bonding process. Its function is to form physical isolation and buffer protection for the connection area between the true tab 130 and the empty foil area 1111.

[0058] The first active layer 1113 is processed to form a receiving groove 1114, exposing the empty foil area 1111 of the first current collector 1112. The electrode tab 130 is inserted into this area and connects with the empty foil area 1111. A protective adhesive 160 covers the surface of the first active layer 1113 on the side away from the first current collector 1112, and its projected area completely covers the projected area of ​​the receiving groove 1114, protecting the connection area between the electrode tab 130 and the empty foil area 1111. During the stacking of the battery cell 100, the protective adhesive 160 is located between the electrode tab 130 and the adjacent separator 120 or electrode sheet 110, preventing structural damage to the connection area between the electrode tab 130 and the empty foil area 1111 caused by mechanical stress or electrochemical side reactions.

[0059] The first electrode 111 also includes a second active layer 1115. The second active layer 1115 is disposed on the side of the first current collector 1112 away from the first active layer 1113. The second active layer 1115 covers the empty foil area 1111 along the thickness direction of the stacking direction. The second active layer 1115 refers to the active material layer disposed on the back of the first current collector 1112. Specifically, it can be achieved by coating or pressing process. The empty foil area 1111 of the first electrode 111 is provided with a receiving groove 1114 on only one side of the first current collector 1112. The second active layer 1115 is completely covered on the other side, retaining more energy storage medium, thereby reducing the impact of the slotting of the first active layer 1113 on the energy density of the cell 100.

[0060] Of course, in other embodiments, the first electrode 111 may also adopt a double-sided slotted design. Specifically, a receiving slot 1114 is opened in both the first active layer 1113 and the second active layer 1115 to further improve the safety performance of the cell 100. This application does not limit this.

[0061] In some embodiments, the electrode 110 adjacent to the first electrode 111 and located on the side where the true tab 130 of the first electrode 111 is located includes a second current collector 1141 and a third active layer 1142 disposed on one side of the second current collector 1141. The third active layer 1142 has a thinning region 1143. The thinning region 1143 is disposed opposite to the empty foil region 1111, and the thinning region 1143 covers the projection area of ​​the receiving groove 1114 in the first current collector 1112. The thinning region 1143 refers to the region in the third active layer 1142 where the thickness is reduced. Specifically, it can be achieved by adjusting the coating parameters or by local grinding. The thinning region 1143 of the third active layer 1142 forms a recessed structure complementary to the protective adhesive 160 by reducing the local material thickness. The complementary structure of the thinning region 1143 and the protective adhesive 160 can eliminate local protrusions in the thickness direction, thereby maintaining the surface flatness of the battery cell 100 after encapsulation.

[0062] In some embodiments, such as Figure 2 and Figure 3As shown, the empty foil area 1111 includes a first area 11111 and a second area 11112 arranged sequentially along the protruding direction of the dummy electrode tab 1121. The width of the first area 11111 is greater than the width of the second area 11112. The true electrode tab 130 includes a first electrode tab portion 131 and a second electrode tab portion 132 connected together. The width of the first electrode tab portion 131 is greater than the width of the second electrode tab portion 132. The first electrode tab portion 131 is connected to the first area 11111, and a portion of the second electrode tab portion 132 is connected to the second area 11112. The remaining portion of the second electrode tab portion 132 is exposed at the edge of the first electrode plate 111. The first area 11111 refers to the area located in the empty foil area 1111 near the center of the electrode plate 110. Specifically, it can be implemented as a rectangular area extending along the protruding direction of the dummy electrode tab 1121, with its width set greater than that of the second area 11112 to enhance the connection area. The second region 11112 refers to the area located in the empty foil region 1111 near the edge of the electrode 110. Specifically, it can be implemented as a trapezoidal region with decreasing width or a rectangular region with a width smaller than the first region 11111. Its width is adjusted according to the lead-out requirements of the true electrode tab 130 to reduce the coating cleaning area. The first electrode tab 131 refers to the portion of the true electrode tab 130 connected to the first region 11111. Specifically, it can be implemented using a metal foil with a width matching the first region 11111, and is fixed to the first region 11111 by spot welding or laser welding. The second electrode tab 132 refers to the portion of the true electrode tab 130 connected to the second region 11112 and extending outwards. Specifically, it can be implemented using a strip structure with a width smaller than the first electrode tab 131, with its end extending to the edge of the electrode 110 to achieve external conductive connection.

[0063] In this embodiment, the empty foil area 1111 is divided into a first area 11111 and a second area 11112 with different widths. The first electrode tab 131 is connected to the first area 11111 by a large-area welding to form a stable connection, ensuring the mechanical strength of the true electrode tab 130 and the electrode sheet 110. A portion of the second electrode tab 132 is connected to the second area 11112, and the remaining portion extends outward to the outside of the electrode sheet 110. Since the width of the second area 11112 is smaller than that of the first area 11111, the area of ​​the active layer that needs to be removed during welding or cleaning is limited to the second area 11112. The first electrode tab 131 is connected to the first area 11111 by a large-area welding to form a stable connection, ensuring the mechanical strength of the true electrode tab 130 and the electrode sheet 110. A portion of the second electrode tab 132 is connected to the second area 11112, and the remaining portion extends outward to the outside of the electrode sheet 110. Since the width of the second region 11112 is smaller than that of the first region 11111, the area of ​​the active layer that needs to be removed during welding or cleaning is limited to the second region 11112.

[0064] Furthermore, such as Figure 2 and Figure 5As shown, in the direction perpendicular to the protruding direction of the dummy tab 1121, the size of the true tab 130 is larger than that of the dummy tab 1121, and the vertical projection of the true tab 130 onto the plane containing the dummy tab 1121 completely covers the dummy tab 1121. The protruding direction of the dummy tab 1121 refers to the direction in which the dummy tab 1121 extends outward from the main body of the electrode 110, and is usually perpendicular to the stacking direction of the electrode 110. Specifically, this can be achieved by forming a protruding structure on the edge of the electrode 110. This direction determines the spatial arrangement of the dummy tab 1121 and the true tab 130 during cell packaging. The phrase "the true electrode 130's vertical projection on the plane where the false electrode 1121 is located completely covers the false electrode 1121" means that the projection outline of the true electrode 130 completely envelops the false electrode 1121 in the overlapping area between the two in space. This can be achieved by designing the true electrode 130 as a wider strip structure. This design ensures that the false electrode 1121 is always within the coverage area of ​​the true electrode 130 during the welding process.

[0065] When the width of the true tab 130 is greater than that of the dummy tab 1121, the true tab 130 can completely cover the connection surface of the dummy tab 1121 when they are welded along a plane other than the stacking direction. During the welding process, because the true tab 130 completely covers the dummy tab 1121, the welding energy can be evenly distributed in the contact area between the two, avoiding welding failure caused by local non-coverage. At the same time, the overlapping areas of the true tab 130 and the dummy tab 1121 are perfectly aligned in the projection direction. When the connection structure formed after welding is subjected to mechanical stress during battery charging and discharging, the stress distribution is more uniform, reducing the risk of connection breakage due to misalignment.

[0066] For example, the width of the second zone 11112 of the true electrode 130 can be designed to be 4mm, and the width of the dummy electrode 1121 can be 3mm. The distance from the edge of the dummy electrode 1121 to the edge of the true electrode 130 is greater than or equal to 0.5mm, so as to prevent the width edge of the dummy electrode 1121 from exceeding the width edge of the true electrode 130, thereby ensuring the effectiveness of the welding.

[0067] The electrode 110 can be divided into multiple positive electrode 110a and multiple negative electrode 110b according to its polarity. The current collector of the positive electrode 110a can be aluminum foil, and the active material of the positive electrode 110a can be lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), ternary materials, etc. The current collector of the negative electrode 110b can be copper foil, and the active material of the negative electrode 110b can be graphite (natural graphite, artificial graphite), lithium titanate (Li4Ti5O12), silicon-based materials (such as silicon, silicon oxide, silicon-carbon composite materials, etc.).

[0068] Each of the multiple positive electrode plates 110a has a first electrode plate 111 and multiple second electrode plates 112, and each of the multiple negative electrode plates 110b also has a first electrode plate 111 and multiple second electrode plates 112. The first electrode plate 111 of the positive electrode plate 110a and the first electrode plate 111 of the negative electrode plate 110b are only different in the materials of the current collector and the active material. The second electrode plate 112 of the positive electrode plate 110a and the second electrode plate 112 of the negative electrode plate 110b are only different in the materials of the current collector and the active material. This application will not describe this in detail.

[0069] It should be noted that while the first electrode 111 of the positive electrode 110a is connected to the true electrode tab 130, it may also have a thinning region 1143 to accommodate the protective adhesive 160 attached to the first electrode 111 of the negative electrode 110b; while the first electrode 111 of the negative electrode 110b is connected to the true electrode tab 130, it may also have a thinning region 1143 to accommodate the protective adhesive 160 attached to the first electrode 111 of the positive electrode 110a. This application does not limit this.

[0070] The size of the positive electrode 110a is smaller than the size of the negative electrode 110b. The smaller size of the positive electrode 110a means that the planar projected area of ​​the positive electrode 110a is completely covered by the negative electrode 110b. Specifically, this can be achieved by shortening the length or width of the positive electrode 110a by a certain amount compared to the negative electrode 110b. This size difference allows the edge of the positive electrode 110a to be wrapped by the negative electrode 110b, so that the negative electrode 110b can have more active material, which is conducive to the insertion of lithium ions and avoids the formation of metallic lithium dendrites on the surface of the negative electrode 110b, thus reducing the risk of short circuit.

[0071] like Figure 2 and Figure 8As shown, the positive electrode 110a includes a main body 1131 and a dummy tab 1121. The main body 1131 has a second edge 1132, and the dummy tab 1121 protrudes from the second edge 1132. An insulating layer 1133 is provided on the portion of the main body 1131 near the second edge 1132. The dummy tab 1121 refers to a conductive protrusion formed by extending the main body 1131 of the positive electrode 110a. Specifically, it can be integrally stamped with the positive current collector. This structure allows the dummy tab 1121 and the true tab 130 to form a conductive connection path. The insulating layer 1133 refers to a non-conductive material layer covering the area of ​​the main body 1131 near the second edge 1132. Specifically, it can be implemented using polyimide tape or a ceramic coating. Since the size of the positive electrode 110a is smaller than that of the negative electrode 110b, and the positive electrode 110a is formed by cutting, burrs are easily formed. The insulating layer 1133 can cover these burrs, preventing them from directly contacting the negative electrode 110b or the separator 120, thus reducing the risk of short circuits. Furthermore, the insulating layer 1133 improves battery consistency by adjusting the interface impedance, uniformly distributing current, suppressing lithium plating and gas generation.

[0072] Secondly, this application also provides a battery, which includes the cell 100 of the first aspect. Thanks to the improvements made to the cell 100 in the above embodiments, the battery of this application has the same technical effects as the cell 100 in the above embodiments, which will not be repeated here.

[0073] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention 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 invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery cell, characterized in that, It includes electrodes, diaphragms, and true electrodes. Multiple electrodes are stacked together, with adjacent electrodes having opposite polarities, and the diaphragm is provided between adjacent electrodes. The plurality of electrodes of the same polarity include a first electrode and a second electrode. The first electrode has an empty foil area. A portion of the structure of the true electrode tab is located between the first electrode and the adjacent diaphragm. The true electrode tab is connected to the empty foil area. The second electrode has a protruding dummy electrode tab. The dummy electrode tab is electrically connected to the portion of the true electrode tab exposed on the first electrode.

2. The battery cell according to claim 1, characterized in that, The battery cell also includes a package, which includes a first package portion and a second package portion. The first package portion has an inner cavity, and the electrode and the diaphragm are packaged in the inner cavity. The second package portion has a channel communicating with the inner cavity. The second package portion covers the connection between the dummy electrode and the real electrode, and part of the real electrode passes through the channel.

3. The battery cell according to claim 2, characterized in that, The dummy electrode and the real electrode have an overlapping structure along the stacking direction, the second encapsulation part covers at least part of the overlapping structure, and electrode adhesive is filled between the second encapsulation part and the overlapping structure.

4. The battery cell according to claim 2, characterized in that, The diaphragm has a first edge, the dummy tab protrudes from the first edge, and the distance between the first encapsulation portion and the first edge is 0 to 1 mm.

5. The battery cell according to claim 1, characterized in that, The first electrode includes a first current collector and a first active layer disposed on one side of the first current collector, the first active layer forming a receiving groove to expose the empty foil area; The battery cell also includes a protective adhesive, which is disposed on the side of the first active layer away from the first current collector, and the protective adhesive covers the projection area of ​​the receiving groove in the first current collector.

6. The battery cell according to claim 5, characterized in that, The first electrode further includes a second active layer, which is disposed on the side of the first current collector opposite to the first active layer, and the second active layer covers the empty foil area along the thickness stacking direction; and / or, The electrode adjacent to the first electrode and located on the side where the true electrode tab is located includes a second current collector and a third active layer disposed on one side of the second current collector. The third active layer has a thinning region. The thinning region is disposed opposite to the empty foil region, and the thinning region covers the projection region of the receiving groove on the first current collector in the projection region of the first current collector.

7. The battery cell according to claim 1, characterized in that, The empty foil area includes a first area and a second area arranged sequentially along the protruding direction of the dummy electrode tab, wherein the width of the first area is greater than the width of the second area; The true electrode tab includes a first electrode tab portion and a second electrode tab portion connected together. The width of the first electrode tab portion is greater than the width of the second electrode tab portion. The first electrode tab portion is connected to the first region, a portion of the second electrode tab portion is connected to the second region, and the remaining portion of the second electrode tab portion is exposed at the edge of the first electrode plate.

8. The battery cell according to claim 1, characterized in that, In a direction perpendicular to the protruding direction of the dummy electrode, the size of the true electrode is larger than the size of the dummy electrode, and the vertical projection of the true electrode onto the plane containing the dummy electrode completely covers the dummy electrode.

9. The battery cell according to claim 1, characterized in that, The plurality of electrodes includes a plurality of positive electrodes and a plurality of negative electrodes; the size of the positive electrodes is smaller than the size of the negative electrodes; and / or, The positive electrode includes a main body and a dummy electrode tab. The main body has a second edge, and the dummy electrode tab protrudes from the second edge. An insulating layer is provided on the portion of the main body near the second edge.

10. A battery, characterized in that, The battery comprises a cell as described in any one of claims 1 to 9.

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