Pole piece and battery cell

Abstract

The utility model provides a pole piece and a battery cell. The pole piece comprises a current collector, an active material layer and a tab, the active material layer is arranged on at least one side of the current collector, the active material layer comprises a groove, and the groove is exposed out of the current collector; the tab is positioned in the groove and is electrically connected with the current collector; the active material layer located on the peripheral side of the groove comprises a main body area and an extension area located on the side, close to the groove, of the main body area, the groove is defined by the side wall, away from the main body area, of the extension area, and the thickness of the extension area in the first direction is smaller than that of the main body area in the first direction; and the pole piece also comprises an adhesive layer bonded between the tab and the current collector, so that the connection strength and stability of the tab can be improved, and the safety and other performances of the battery are ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to an electrode and a battery cell. Background Technology

[0002] Currently, lithium-ion batteries are widely used not only in portable electronic devices such as mobile phones and laptops, but also in electric vehicles, electric bicycles and other electric equipment.

[0003] The battery cell is the core component of a lithium-ion battery. A battery cell includes a positive electrode and a negative electrode, both of which include a current collector and an active material layer disposed on the current collector. Both the positive and negative electrodes have tabs. However, in related technologies, the connection strength and stability of the tabs are poor, and stress concentration during the tab welding process can easily lead to electrode breakage or powder shedding. Utility Model Content

[0004] In view of this, the present invention aims to provide an electrode and a battery cell to improve the connection strength and stability of the electrode tabs and prevent the electrode from cracking or shedding powder due to stress concentration during the welding process of the electrode tabs.

[0005] In a first aspect, this utility model provides an electrode sheet, comprising a current collector, an active material layer, and an electrode tab;

[0006] The active material layer is disposed on at least one side of the current collector, the active material layer includes a groove that exposes the current collector; the tab is located in the groove and is electrically connected to the current collector;

[0007] The active material layer located around the groove includes a main region and an extension region located on the side of the main region closer to the groove, and the side wall of the extension region away from the main region surrounds the groove;

[0008] The thickness of the extension region along the first direction is less than the thickness of the main body region along the first direction;

[0009] The electrode also includes an adhesive layer bonded between the tab 200 and the current collector 1.

[0010] Optionally, the groove includes two side walls disposed opposite each other along the second direction and a bottom wall connecting the two side walls;

[0011] The included angle α between the sidewall and the bottomwall of the tank satisfies: 90°≤α≤160°;

[0012] And / or, the groove includes two side groove walls disposed opposite each other along the second direction and a bottom wall connecting the two side groove walls;

[0013] The sidewall and the bottomwall of the tank are smoothly transitioned by an arc-shaped wall.

[0014] Optionally, the projected width d of the arc-shaped wall in the third direction satisfies: 1mm≤d≤10mm;

[0015] And / or, the ratio of the projected width d of the arcuate wall in the third direction to the groove depth b in the third direction satisfies: 0.03≤d / b≤0.5;

[0016] And / or, the projected length e of the arcuate wall in the second direction satisfies: 1mm≤e≤10mm;

[0017] And / or, the ratio of the projected length e of the arcuate wall along the second direction to the groove width D along the second direction satisfies: 0.05≤e / D≤0.5.

[0018] Optionally, the thickness of the extension region gradually decreases in the first direction along the direction away from the main body region;

[0019] And / or, the side surface of the extended region facing away from the current collector is an arc-shaped surface;

[0020] And / or, the angle β between the side surface of the extension region facing away from the current collector and the current collector satisfies: 3°≤β≤80°;

[0021] And / or, in the direction from the main body region to the extension region, the length E of the extension region satisfies: 0.5mm≤E≤10mm;

[0022] Preferably, the length E of the extension region satisfies: 2mm ≤ E ≤ 7mm;

[0023] And / or, along the second direction, the thickness of the main body region located on one side of the groove is not greater than the thickness of the main body region located on the other side of the groove.

[0024] Optionally, a protrusion is provided on the side of the extension area near the groove, and the protrusion extends toward the groove.

[0025] Optionally, in the direction close to the groove, the maximum length c of the projection of the protrusion onto the current collector satisfies: c≤2mm;

[0026] And / or, the protrusion is provided on an extension area located on at least one side of the groove along the second direction, and the ratio of the maximum length c of the projection of the protrusion in the second direction to the groove width D of the groove along the second direction satisfies: c / D≤1 / 3.

[0027] Optionally, the protrusion includes at least two protrusions arranged in sequence, each of which extends toward the groove.

[0028] Optionally, in the direction toward the groove, the projected width h of the protrusion on the current collector gradually decreases;

[0029] And / or, in the direction toward the groove, the projected width h of the protrusion on the current collector satisfies: 100μm≤h≤1500μm;

[0030] And / or, a recess is formed between two adjacent protrusions, wherein the distance L between the projection of the end of the protrusion closer to the recess on the current collector and the projection of the end of the recess farther from the recess on the current collector satisfies: 20μm≤L≤2000μm;

[0031] And / or, the angle s between the line connecting the end of the protrusion near the groove and the end of the two adjacent recesses satisfies: 30°≤s≤75°.

[0032] Optionally, in the third direction, a notch is formed on one side edge of the portion of the current collector corresponding to the groove;

[0033] And / or, along the first direction, the current collector has opposing first and second sides, the groove is located on the first side, and the area on the second side corresponding to the groove is not coated with the active material layer;

[0034] The uncoated area on the second side has a misalignment distance F between its projected edge in the second direction and the projected edge of the groove in the second direction;

[0035] The misalignment distance F satisfies: F≤0.5mm;

[0036] And / or, along the first direction, the current collector 1 has a first side 13 and a second side 14 opposite each other, the groove 3 is located on the first side 13, and the projection of the groove 3 in the thickness direction of the current collector overlaps with the projection of the active material layer 2 on the second side 14.

[0037] Optionally, the groove 3 includes two side groove walls 31 arranged opposite to each other along the second direction and a bottom groove wall 32 connected between the two side groove walls 31;

[0038] In the second direction, the boundary of the adhesive layer is located between the edge of the tab 200 and the side groove wall 31, and / or

[0039] In a third direction, the boundary of the adhesive layer is located between the edge of the tab 200 and the bottom wall 32 of the groove; and / or

[0040] Along the first direction, the maximum thickness of the adhesive layer is 10-30 micrometers.

[0041] Secondly, this utility model provides a battery cell, including a first electrode and a second electrode;

[0042] At least one of the first electrode and the second electrode is an electrode as described above.

[0043] The electrode and battery cell provided by this utility model include grooves in the active material layer, exposing the current collector in the grooves, and placing the electrode tabs within the grooves, thus electrically connecting the electrode tabs to the current collectors. In other words, by including grooves in the active material layer and assembling the electrode tabs within the grooves, the grooves can limit and fix the electrode tabs to a certain extent, improving the ease of electrode tab assembly and enhancing the connection strength and stability of the electrode tabs.

[0044] Because the active material layer includes grooves that expose the current collector, when the active material layer is coated on the current collector, the position on the current collector corresponding to the mounting tab is not coated with the active material layer. This leaves the tab mounting area uncoated during coating, allowing the grooves to be formed directly upon coating completion. This enables the tab to connect directly to the current collector. Compared to the previous method of first coating the tab mounting area of ​​the current collector, then cleaning off that portion of the active material layer, and finally connecting the tab to the current collector with the cleaned active material layer, this invention, by not coating the area of ​​the current collector connecting to the tab with the active material layer, avoids damage to the current collector during cleaning, which could affect the connection strength and stability of the tab and increase the internal resistance of the tab area. This further improves the connection strength and stability between the tab and the current collector and reduces the battery's internal resistance, thus ensuring battery safety and charging performance. Furthermore, this design reduces the consumption of the active material layer, saving manpower and resources required for cleaning the active material layer, reducing energy consumption, and contributing to a greener electrode production process.

[0045] Moreover, since the tabs are located inside the grooves, the thickness at the corresponding positions of the tabs is reduced to a certain extent, thereby reducing the thickness of the battery cell, which helps to improve the energy density per unit volume of the battery cell.

[0046] Meanwhile, the active material layer around the groove includes a main area and an extension area located near the groove side of the main area. The side wall of the extension area away from the main area forms the groove, and the thickness of the extension area along the first direction is less than the thickness of the main area along the first direction. This makes the area of ​​the active material layer near the groove periphery a thinning zone, allowing for a better transition at the junction of the active material layer around the groove and the current collector at the groove. This prevents stress concentration at the junction from causing electrode breakage or powder shedding of the active material layer, ensuring the cleanliness of the groove area and further improving the connection strength and stability of the electrode tab. Moreover, during electrode rolling, the extension area can play a certain buffering role, avoiding sudden changes in force during electrode rolling that could cause electrode breakage or bright strips.

[0047] In addition, since the electrode may also include an adhesive layer bonded between the tab and the current collector, the adhesive layer can avoid the risk of the weld marks caused by welding easily puncturing the diaphragm or coming into contact with the electrode and causing a short circuit, and can further prevent the tab and current collector from easily cracking at the welding position during the welding process.

[0048] In addition, when the tab protective adhesive is applied to the tab, a thinning zone is formed in the area of ​​the active material layer near the groove, which leaves a certain space for the tab protective adhesive. After the tab protective adhesive is applied, the thickness of the electrode sheet at the tab protective adhesive can be reduced to a certain extent, which is conducive to improving the energy density per unit volume of the cell. Attached Figure Description

[0049] Figure 1 This is a top view of the electrode sheet according to an embodiment of the present invention. Figure 1 .

[0050] Figure 2 for Figure 1 A schematic diagram of a local structure.

[0051] Figure 3 This is a schematic cross-sectional view of the electrode sheet according to an embodiment of the present invention. Figure 1 .

[0052] Figure 4 for Figure 3 Enlarged schematic diagram of the structure at point I.

[0053] Figure 5 This is a top view of the electrode sheet according to an embodiment of the present invention. Figure 2 .

[0054] Figure 6 for Figure 5 A schematic diagram of a local structure.

[0055] Figure 7 for Figure 6A schematic diagram of a local structure.

[0056] Figure 8 This is a schematic cross-sectional view of the electrode sheet according to an embodiment of the present invention. Figure 2 .

[0057] Among them, 100 is the electrode sheet; 1 is the current collector; 11 is the coating area; 12 is the empty foil area; 121 is the notch; 13 is the first side; 14 is the second side; 2 is the active material layer; 21 is the main body area; 22 is the extension area; 23 is the arc-shaped surface; 24 is the protrusion; 241 is the protrusion; 242 is the concave part; 3 is the groove; 31 is the side groove wall; 32 is the bottom wall of the groove; 33 is the arc-shaped wall; 200 is the tab. Detailed Implementation

[0058] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0059] The battery cell is the core component of a lithium-ion battery. A battery cell includes a positive electrode and a negative electrode, both of which include a current collector and an active material layer disposed on the current collector. Both the positive and negative electrodes have tabs. However, in related technologies, the connection strength and stability of the tabs are poor, affecting battery safety and other performance characteristics. If the connection strength and stability of the tabs are poor, stress concentration during the tab welding process can easily lead to electrode breakage or powder shedding.

[0060] Based on this, the present invention provides an electrode, a cell, and a battery that eliminates the need to remove part of the active material layer on the electrode, expose part of the current collector, and then install tabs at the exposed current collector location. Instead, by leaving the active material layer uncoated at the location where the tabs are to be installed on the current collector, the tab installation area is left blank during the paste application process. This allows a groove for installing the tabs to be formed directly at the same time as the paste application is completed. This avoids damage to the current collector during the cleaning of the active material layer, which could affect the connection strength and stability of the tabs and the internal resistance of the tab area. This improves the safety and charging performance of the battery. At the same time, by thinning the active material layer in the area around the groove, the junction between the active material layer and the current collector at the groove is buffered, preventing stress concentration at the junction that could cause the electrode to break.

[0061] The electrode sheet and battery cell provided by this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] Reference Figures 1 to 8As shown, this embodiment provides an electrode 100, which is applied to a battery cell. The battery cell can be a wound cell or a stacked cell. The battery cell is used in a battery, such as a lithium-ion battery.

[0063] The electrode 100 in this embodiment may specifically include: a current collector 1, an active material layer 2, and a tab 200.

[0064] The active material layer 2 is disposed on at least one side of the current collector 1, and the active material layer 2 includes a groove 3 that exposes the current collector 1. The tab 200 is located in the groove 3 and is electrically connected to the current collector 1.

[0065] Reference Figures 1 to 6 As shown, the active material layer 2 around the groove 3 includes a main region 21 and an extension region 22 located on the side of the main region 21 near the groove 3. The side wall of the extension region 22 away from the main region 21 forms the groove 3.

[0066] Continue to refer to Figure 3 The thickness m of the extension region 22 along the first direction is less than the thickness k of the main body region 21 along the first direction.

[0067] Among them, the first direction is, for example, Figure 3 The vertical direction can be specifically the thickness direction of electrode 100.

[0068] The aforementioned active material layer 2 includes a groove 3, which exposes the current collector 1. The tab 200 is located in the groove 3 and is electrically connected to the current collector 1. Specifically, during the process of coating the active material layer 2 on the current collector 1, the mounting area of ​​the tab 200 does not participate in the coating process. That is, the active material layer 2 will never exist at the location where the current collector 1 is connected to the tab 200, rather than first coating the mounting area of ​​the tab with the active material layer and then cleaning off the active material layer at that location.

[0069] For example, in combination Figure 1 and Figure 3 For example, before coating the active material layer 2, a blade pad or similar device can be used to cover the area on the current collector 1 where the tab 200 is connected, and the active material layer 2 can be coated on at least the portion of the current collector 1 located outside this area, thus leaving the area where the tab 200 is connected empty. This achieves irregular coating of the active material layer 2. After the active material layer 2 is coated, a groove 3 for mounting the tab 200 can be directly formed on the active material layer 2, and the groove 3 can expose the current collector 1. Then, after processes such as rolling and slitting, a battery is formed.

[0070] In one specific example, the tab 200 can be connected to the current collector 1 by welding, and the tab 200 can extend from one edge of the current collector 1. To prevent short circuits caused by contact between the tab 200 and the current collector 1 and other components, protective adhesive can be applied to the connection point to protect the tab 200 and the connection point. In another specific example, the electrode may also include an adhesive layer bonded between the tab 200 and the current collector 1. The adhesive layer is a conductive adhesive layer, and the tab 200 and the current collector 1 are electrically connected through the conductive adhesive layer. Compared to welding, the adhesive layer connection method avoids the risk of solder marks easily piercing the diaphragm or contacting the electrode, causing short circuits. It also further prevents cracking at the weld point during the welding process between the tab and the current collector.

[0071] For ease of explanation, refer to Figures 1 to 6 As shown, the current collector 1 may specifically include: a coated area 11 and an empty foil area 12, wherein the empty foil area 12 is located along a third direction of the current collector 1 (e.g., in a third direction). Figure 1 The vertical direction (specifically, the width direction of electrode 100) is one edge on one side.

[0072] Among them, reference Figure 3 Along the first direction (e.g., for) Figure 3 and Figure 8 In the vertical direction (specifically, the thickness direction of the electrode 100), the current collector 1 has a first side 13 and a second side 14. For example, the first side 13 can be the current collector 1 in the vertical direction (specifically, the thickness direction of the electrode 100). Figure 3 On the upper side, the second side 14 can be a current collector 1. Figure 3 The lower side of the middle.

[0073] For example, an active material layer 2 can be coated on at least the first side 13 of the coating area 11, so that at least the first side 13 of the empty foil area 12 is not coated with the active material layer 2, thereby exposing the empty foil area 12 and forming the groove 3 mentioned above. That is, the groove 3 can be located on the first side 13.

[0074] For coating area 11, refer to Figure 3 As shown, specifically, the active material layer 2 can be coated only on the first side 13 of the coating area 11; see reference. Figure 8 As shown, the active material layer 2 can also be coated on both the first side 13 and the second side 14 of the coating area 11.

[0075] For the empty foil region 12, specifically, the active material layer 2 may not be coated on the first side 13 of the empty foil region 12, while the active material layer 2 may be coated on the second side 14 of the empty foil region 12; see reference. Figure 8 Alternatively, the active material layer 2 may not be coated on either the first side 13 or the second side 14 of the empty foil area 12.

[0076] In practice, there can be one groove 3. Of course, there can also be two or three grooves 3 to form a bipolar or tripolar electrode.

[0077] In this embodiment, the electrode 100 can be either a positive electrode or a negative electrode.

[0078] The electrode sheet provided in this embodiment includes a groove 3 in the active material layer 2, exposing the current collector 1 in the groove 3, and the tab 200 is disposed in the groove 3, making the tab 200 electrically connected to the current collector 1. In other words, by including the groove 3 in the active material layer 2 and assembling the tab 200 in the groove 3, the groove 3 can limit and fix the tab 200 to a certain extent, improving the ease of assembly and enhancing the connection strength and stability of the tab 200. Since the active material layer 2 includes a groove 3 that exposes the current collector 1, when the active material layer 2 is coated on the current collector 1, the position on the current collector 1 corresponding to the mounting tab 200 is not coated with the active material layer 2. That is, the mounting area of ​​the tab is left empty during the coating process. Thus, the groove 3 can be directly formed at the same time as the coating is completed, so that the tab 200 can be directly connected to the current collector 1. Compared with the solution of first coating the active material layer on the tab mounting area of ​​the current collector, then cleaning off that part of the active material layer, and then connecting the tab to the current collector with the cleaned active material layer, since the active material layer 2 has not been coated on the area of ​​the current collector 1 where the tab 200 is connected in this embodiment, on the one hand, it can avoid the current collector 1 being damaged during the cleaning of the active material layer 2, which would affect the connection strength and stability of the tab 200 and cause the internal resistance of the tab area to increase. That is, it further improves the connection strength and stability between the tab 200 and the current collector 1 and reduces the internal resistance of the battery, thereby ensuring the safety performance and charging performance of the battery. On the other hand, this setup can also reduce the consumption of active material layer 2 to a certain extent, save manpower and resources required for cleaning active material layer 2, reduce energy consumption, and help achieve green production of electrode 100.

[0079] Moreover, since the tab 200 is located inside the groove 3, the thickness at the corresponding position of the tab 200 is reduced to a certain extent, thereby reducing the thickness of the battery cell, which is beneficial to improving the energy density per unit volume of the battery cell.

[0080] Meanwhile, the active material layer 2 around the groove 3 includes a main area 21 and an extension area 22 located on the side of the main area 21 near the groove 3. The side wall of the extension area 22 away from the main area 21 forms the groove 3, and the thickness of the extension area 22 along the first direction is less than the thickness of the main area 21 along the first direction. This makes the area of ​​the active material layer 2 near the groove 3 a thinning area, so that the joint between the active material layer 2 around the groove 3 and the current collector 1 at the groove 3 can be better transitioned, preventing stress concentration at the joint from causing the electrode 100 to crack or the active material layer 2 to fall off. This ensures the cleanliness of the groove 3 area and further improves the connection strength and stability of the tab 200. Moreover, when the electrode 100 is rolled, the extension area 22 can play a certain buffering role, avoiding sudden changes in force during the rolling of the electrode 100, which could cause the electrode to break, have bright strips, or form a dense layer on the surface of the active material layer 2, thus affecting lithium ion transport.

[0081] In addition, when the tab protective adhesive is pasted at the tab 200, a thinning zone is formed in the area of ​​the active material layer 2 near the groove 3, which leaves a certain space for the tab protective adhesive. After the tab protective adhesive is pasted, the thickness of the electrode sheet 100 at the tab protective adhesive can be reduced to a certain extent, which is conducive to improving the energy density per unit volume of the battery cell.

[0082] In some embodiments, refer to Figure 2 As shown, the groove 3 includes two side groove walls 31 and a bottom wall 32 connecting the two side groove walls 31. The two side groove walls 31 are arranged opposite each other along a second direction. The tab 200 extends from the opening of the groove 3.

[0083] Among them, the second direction is, for example, Figure 2 The left and right directions in the middle can specifically refer to the length direction of electrode 100.

[0084] In some embodiments, refer to Figure 2 As shown, the included angle α between the side wall 31 and the bottom wall 32 of the tank satisfies: 90°≤α≤160°. For example, the included angle α can be 90°, 95°, 100°, 110°, 120°, 125°, 135°, 140°, 145°, 155°, or 160°.

[0085] Reference Figure 2 As shown, the angle α between the side wall 31 and the bottom wall 32 can be specifically the angle α between the extension line of the side wall 31 and the extension line of the bottom wall 32.

[0086] By setting the included angle α within the aforementioned range, the accumulation of the active material layer 2 at the junction of the side wall 31 and the bottom wall 32 can be avoided to a certain extent. This prevents powder shedding at the junction of the side wall 31 and the bottom wall 32 in subsequent processes, ensuring the cleanliness of the groove 3 area. This further ensures the connection strength and stability of the tab 200 at the groove 3, thereby further guaranteeing the battery's safety and other performance characteristics. It also reduces the internal resistance of the tab 200 area and improves the battery's charging performance.

[0087] In some embodiments, continue to refer to Figure 2 The side wall 31 and the bottom wall 32 are smoothly transitioned by an arc-shaped wall 33. This design can, to a certain extent, avoid stress concentration at the joint between the side wall 31 and the bottom wall 32, thus preventing damage or breakage. It also improves the structural strength and stability of the side wall 31 and the bottom wall 32, further preventing powder shedding from the active material layer 2 during subsequent processing, further ensuring the cleanliness of the groove 3 area, and further improving the connection strength and stability of the tab 200.

[0088] In some embodiments, along the first direction, the current collector 1 has a first side 13 and a second side 14 opposite to each other, and the groove 3 is located on the first side 13. The projection of the groove 3 in the thickness direction of the current collector overlaps with the projection of the active material layer 2 on the second side 14. That is, an active material layer is formed on the back side of the corresponding groove of the current collector, thereby improving the overall energy density of the battery cell. At the same time, in embodiments where the tabs are connected to the current collector via conductive adhesive, the flatness of the active material layer on the back side can be ensured while improving the energy density of the battery cell, preventing partial deactivation of the active material layer due to welding.

[0089] In some embodiments, by setting the included angle α as described above and making the side groove wall 31 and the bottom groove wall 32 smoothly transition through the arc-shaped wall 33, the active material layer 2 at the junction of the side groove wall 31 and the bottom groove wall 32 can exhibit a natural flow state in the thickness direction of the electrode sheet 100. This can further prevent the active material layer 2 from accumulating at the junction of the side groove wall 31 and the bottom groove wall 32, prevent powder from falling off at the junction, further improve the cleanliness of the groove 3 area, and further ensure the connection strength and stability of the tab 200, and ensure the safety and other performance of the battery.

[0090] Combination Figure 1 and Figure 2 As shown, in some embodiments, the projected width d of the arcuate wall 33 in the third direction satisfies: 1mm≤d≤10mm.

[0091] Reference Figure 2 As shown, the third party here is, for example, Figure 2The vertical direction can specifically be the width direction of the electrode 100. For example, the projection width d can be 1mm, 2mm, 3mm, 4mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0092] By setting the projection width d within the above range, it is possible to ensure that there is no active material layer 2 at the welding position of the tab 200, thereby improving the cleanliness of the groove 3 area, improving the connection strength and connection stability of the tab 200, and at the same time, it is possible to increase the load of the active material layer 2 to a certain extent, thereby increasing the battery capacity.

[0093] In some embodiments, refer to Figure 1 and Figure 5 As shown, the ratio of the projected width d of the arc-shaped wall 33 in the third direction to the groove depth b of the groove 3 in the third direction satisfies: 0.03≤d / b≤0.5.

[0094] Reference Figure 1 and Figure 5 As shown, the groove depth b of the groove 3 in the third direction is specifically the groove depth b of the groove 3 in the vertical direction. For example, the above ratio can be 0.03, 0.06, 0.1, 0.2, 0.265, 0.3, 0.38, 0.4, 0.45, or 0.5.

[0095] By setting the ratio of the projection width d to the groove depth b within the above range, the cleanliness of the groove 3 area can be improved so that the electrode 200 connection area is free of active material layer 2, thereby ensuring the connection strength of the electrode 200 and increasing the load of active material layer 2 to a certain extent, thus increasing the battery capacity.

[0096] In some embodiments, refer to Figure 1 and Figure 2 As shown, the projected length e of the arc-shaped wall 33 in the second direction is set to satisfy: 1mm≤e≤10mm.

[0097] Reference Figure 2 As shown, the projected length e of the arc-shaped wall 33 in the second direction is specifically the projected length e of the arc-shaped wall 33 along the left-right direction. For example, the projected length e can be 1mm, 2mm, 3mm, 4mm, 5.5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0098] By setting the projection length e within the aforementioned range, the cleanliness of the groove 3 area can be improved, ensuring the connection strength and stability of the tab 200, while also increasing the load on the active material layer 2 to a certain extent, thereby increasing the battery capacity.

[0099] In some embodiments, the ratio of the projected length e of the arcuate wall 33 along the second direction to the groove width D of the groove 3 along the second direction satisfies: 0.05≤e / D≤0.5.

[0100] Reference Figure 1 and Figure 5 As shown, the groove width D of the groove 3 along the second direction is specifically the width of the groove 3 along the left-right direction. For example, the above ratio can be 0.05, 0.08, 0.1, 0.2, 0.275, 0.3, 0.38, 0.4, 0.45, or 0.5.

[0101] By setting the ratio of the projected length e to the groove width D within the above range, it is possible to improve the cleanliness of the groove 3 area so that the electrode 200 connection area is free of active material layer 2, thereby ensuring the connection strength of the electrode 200 and increasing the load of active material layer 2 to a certain extent, thereby increasing the battery capacity.

[0102] In some embodiments, refer to Figure 1 As shown, groove 3 is along the second direction ( Figure 1 The groove width D in the left and right directions of the middle satisfies: 6mm≤D≤20mm.

[0103] For example, the slot width D can be 6mm, 8mm, 10mm, 12mm, 13mm, 15mm, 17mm, 18mm, 19mm, or 20mm.

[0104] By setting the groove width D within the above range, sufficient space is provided when the tab 200 is connected, which improves the connection efficiency of the tab 200 and helps to improve the connection strength and connection stability of the tab 200. At the same time, the load of the active material layer 2 on both sides of the groove 3 along the second direction on the current collector 1 is guaranteed, thereby ensuring the overall capacity of the battery.

[0105] Continue to refer to Figure 1 As shown, in some embodiments, the groove 3 is along a third direction ( Figure 1 The groove depth b in the vertical direction (in the middle) satisfies: 14mm≤b≤30mm.

[0106] For example, the groove depth b can be 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 29mm, or 30mm.

[0107] By setting the groove depth b within the aforementioned range, sufficient space is ensured for the connection of the electrode tab 200, thereby improving the connection efficiency of the electrode tab 200 and guaranteeing the connection effect of the electrode tab 200 at the groove 3, further enhancing the connection strength and stability of the electrode tab 200. Furthermore, this also prevents the groove depth b from being too large, which could affect the current collector 1 located on the third-direction side of the groove 3 (i.e., along the groove 3). Figure 1 The loading of the active material layer 2 (on the lower side of the battery) ensures the overall capacity of the battery.

[0108] In some embodiments, refer to Figure 1 and Figure 5 As shown, groove 3 is along the second direction ( Figure 1 and Figure 5 The groove width D and the groove 3 in the left and right directions are along the third direction (in the middle). Figure 1 and Figure 5 The ratio of the groove depth b in the vertical direction (in the middle) satisfies: 0.2≤D / b≤1.

[0109] For example, the ratios mentioned above could be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.

[0110] By setting the ratio of groove width D to groove depth b within the above range, sufficient space is provided when connecting the tab 200, improving the connection efficiency of the tab 200 and enhancing the connection strength and stability of the tab 200. At the same time, it also ensures the load of the active material layer 2 on the current collector 1 located on the periphery of the groove 3, thereby ensuring the overall capacity of the battery.

[0111] In some embodiments, refer to Figure 1 As shown, current collector 1 is in the third direction ( Figure 1 The width H in the vertical direction (of the image) satisfies: 40mm≤H≤90mm.

[0112] For example, the width H can be 40mm, 50mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, or 90mm.

[0113] In some embodiments, refer to Figure 1 As shown, the groove 3 is positioned along the third direction ( Figure 1 The groove depth b in the vertical direction (in the middle) and the current collector 1 in the third direction (in the middle) Figure 1 The ratio of the width H in the vertical direction (in the middle) satisfies: 0.155≤b / H≤0.5.

[0114] For example, the ratio could be 0.155, 0.2, 0.2576, 0.3, 0.3275, 0.37, 0.4, 0.456, 0.48, or 0.5.

[0115] By setting the ratio of groove depth b to width H within the aforementioned range, sufficient space can be provided to ensure the connection of the tab 200, thereby improving the connection efficiency of the tab 200. Furthermore, this enhances the connection strength and stability of the tab 200 while also increasing the size of the coating area 11. Figure 1 The loading of the active material layer 2 in the vertical direction ensures the battery capacity.

[0116] In some embodiments, refer to Figure 3 and Figure 4 As shown, the thickness m of the extension region 22 gradually decreases in the first direction along the direction away from the main body region 21.

[0117] For example, refer to Figure 3 In the active material layer 2 located on the left side of the groove 3, the thickness m of the extension region 22 gradually decreases from left to right; similarly, in the active material layer 2 located on the right side of the groove 3, the thickness m of the extension region 22 gradually decreases from right to left. For example, referring to... Figure 1 In the active material layer 2 located on the lower side of the groove 3, the thickness of the extension region 22 gradually decreases from bottom to top.

[0118] This design ensures a smooth transition at the junction of the extension region 22 and the main body region 21, allowing the extension region 22 and the main body region 21 to exhibit a natural flow pattern in the thickness direction of the electrode 100. This avoids stress concentration that could lead to breakage or bulging at the junction, and further prevents sudden changes in force on the electrode 100 during rolling, which could cause electrode breakage, bright stripes, or the formation of a dense layer on the surface of the active material layer 2 that could affect lithium-ion transport. Moreover, this design helps to better release the active energy of this portion of the active material layer 2. Simultaneously, this design also ensures a smooth transition at the junction of the extension region 22 and the current collector 1 at the groove 3, preventing stress concentration that could lead to breakage or bulging at the junction. Furthermore, the extension region 22 provides a good buffering effect, further preventing sudden changes in force on the electrode 100 during rolling, which could cause electrode breakage, bright stripes, or the formation of a dense layer on the surface of the active material layer 2 that could affect lithium-ion transport.

[0119] In some embodiments, refer to Figure 4 As shown, the side surface of the extension region 22 facing away from the current collector 1 is an arc-shaped surface 23.

[0120] This allows for a smooth transition at the junction of the extension region 22 and the main body region 21, resulting in a natural flow pattern between the extension region 22 and the main body region 21 in the thickness direction of the electrode 100. This further avoids stress concentration and improves the structural strength and connection stability of the electrode 100. Furthermore, this enhances the buffering effect of the extension region 22, further preventing sudden changes in force during the rolling process that could cause the electrode 100 to break or develop bright strips, or the formation of a dense layer on the surface of the active material layer 2 that could affect lithium-ion transport.

[0121] Of course, in other implementations, the thickness of the extension region 22 may decrease in a stepped manner along the direction away from the main region 21.

[0122] In some embodiments, the angle β between the side surface of the extension region 22 facing away from the current collector 1 and the current collector 1 satisfies: 3°≤β≤80°.

[0123] For example, the included angle α can be 3°, 10°, 20°, 30°, 35°, 41.5°, 45°, 50°, 60°, 70°, or 80°.

[0124] For example, refer to Figure 4 When the side of the extension region 22 facing away from the current collector 1 is formed into an arc-shaped surface 23, the included angle β is specifically the included angle between the tangent of the side of the extension region 22 facing away from the current collector 1 and the surface where the current collector 1 is located (such as the upper surface of the current collector 1).

[0125] By setting the included angle β within the above range, a smooth transition between the extension area 22 and the main body area 21 is further ensured, so that the extension area 22 and the main body area 21 exhibit a natural flow state in the thickness direction of the electrode 100. This can effectively buffer the junction of the extension area 22 and the current collector 1 at the groove 3, and further avoid the phenomenon of electrode 100 breaking or bright strips due to pressure, or the formation of a dense layer on the surface of the active material layer 2.

[0126] Of course, in other embodiments, the side surface of the extension region 22 facing away from the current collector 1 can also be an inclined plane, in which case the aforementioned included angle β refers to the included angle between the inclined plane and the surface where the current collector 1 is located.

[0127] Reference Figure 3 As shown, in some embodiments, the length E of the extension region 22 in the direction from the main body region 21 to the extension region 22 satisfies: 0.5mm≤E≤10mm.

[0128] Reference Figure 3 As shown, located in groove 2 along the second direction (e.g., for Figure 3Taking the extension regions 22 on both sides of the electrode 100 (specifically, the length direction of the electrode 100) as an example, the length E of the extension region 22 is the length E of the extension region 22 along the left and right directions.

[0129] For example, the length E can be 0.5mm, 1mm, 2mm, 3mm, 4.5mm, 5.25mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0130] By setting the length E within the above range, the load of the active material layer 2 can be guaranteed to ensure the battery capacity, while also leaving enough space for the tab protective adhesive. This prevents the electrode sheet at the tab protective adhesive from becoming too thick after bonding, thus avoiding a large cell thickness and further ensuring the energy density per unit volume of the cell.

[0131] Furthermore, the length E can be set to: 2mm≤E≤7mm.

[0132] For example, the length E can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, or 7mm. This further ensures battery capacity and, while reserving sufficient space for the tab protective adhesive, also ensures the energy density per unit volume of the cell.

[0133] In some embodiments, refer to Figure 1 and Figure 3 Along the second direction, the thickness k of the main body region 21 located on one side of the groove 3 is not greater than the thickness k of the main body region 21 located on the other side of the groove 3.

[0134] For example, during the rolling of electrode 100, electrode 100 can, for instance, move along... Figure 1 and Figure 3 When the rollers are rolled from left to right, it can make Figure 1 The thickness of the main body area 21 on the right side of the groove 3 is not greater than the thickness of the main body area 21 on the left side of the groove 3.

[0135] The above settings further ensure the buffering effect during rolling, thereby further avoiding the phenomenon of electrode 100 breaking or bright strips caused by sudden force changes during rolling, or the formation of a dense layer on the surface of the active material layer 2 that affects lithium-ion transport.

[0136] In some embodiments, refer to Figure 6 and Figure 7 As shown, a protrusion 24 is provided on the side of the extension area 22 near the groove 3, and the protrusion 24 extends toward the groove 3.

[0137] For example, the groove 3 can be along the second direction (e.g., for Figure 5 and Figure 6 The aforementioned protrusion is provided on at least one side of the extension region 22 in the left-right direction (specifically, the length direction of the electrode 100), for example, referring to... Figure 5 and Figure 6 The protrusion 24 can be provided on the extension area 22 on the right side of the groove 3. Of course, in other embodiments, the protrusion 24 can also be provided on the extension area 22 on the left side. In addition, the protrusion 24 can also be provided on the extension area 22 on the lower side of the groove 3.

[0138] This increases the contact area between the tab protectant and the active material layer 2, thereby enhancing the adhesion of the tab protectant at that location and ensuring the protection of the tab 200, further guaranteeing the safety of the battery. Furthermore, the protrusion 24 also increases the load on the active material layer 2, which helps maintain battery capacity.

[0139] In some embodiments, the maximum length c of the projection of the protrusion 24 onto the current collector 1 in the direction close to the groove 3 satisfies: c ≤ 2 mm. For example, the maximum length c can be 0.1 mm, 0.4 mm, 0.7 mm, 1 mm, 1.3 mm, 1.6 mm, 1.8 mm, or 2 mm.

[0140] Referring to Figure 6, taking the example of a protrusion 24 provided on the extension area 22 on the right side of the groove 3, the maximum length c of the projection of the protrusion 24 onto the current collector 1 can be the length of the protrusion 24 along the second direction (for example, ...). Figure 6 The left and right directions (specifically, the length of the electrode 100) refer to the length between the leftmost and rightmost edges in the left and right directions.

[0141] By setting the maximum length c within the above range, the bonding area between the tab protective adhesive and the active material layer 2 can be guaranteed, ensuring the bonding performance of both. At the same time, it can also avoid the situation where the protrusion 24 is too long and comes into contact with the connection area of ​​the tab 200, thus affecting the connection strength and stability of the tab 200. This can further guarantee the connection strength and stability of the tab 200.

[0142] In some embodiments, refer to Figure 1 , Figure 5 and Figure 6 As shown, when a protrusion 24 is provided on at least one side of the extension region 22 of the groove 3 along the second direction, the protrusion 24 in the second direction (e.g., as...) Figure 6 The maximum length c of the projection of the groove 3 in the left and right directions is related to the groove 3 in the second direction (e.g., the maximum length c of the projection in the left and right directions). Figure 1 and Figure 5The ratio of the slot width D in the left and right directions satisfies: c / D≤1 / 3.

[0143] For example, the ratios mentioned above could be 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4, or 1 / 3.

[0144] By setting the ratio of the maximum length c to the groove width D within the above range, the bonding area between the tab protective adhesive and the active material layer 2 can be guaranteed, ensuring the bonding performance of both. At the same time, it can also avoid the situation where the protrusion 24 encroaches on the connection area of ​​the tab 200 at the groove 3, thereby helping to ensure the connection area between the tab 200 and the current collector 1, and further ensuring the connection strength of the tab 200.

[0145] In some embodiments, continue to refer to Figure 6 and Figure 7 The protrusion 24 includes at least two protrusions 241 arranged in sequence, each protrusion 241 extending toward the groove 3.

[0146] Among them, reference Figure 6 Taking the protrusion 24 located on the extension area 22 to the right of the groove 3 as an example, for instance, at least two protrusions 241 can be located along a third direction (e.g., for...). Figure 6 The vertical direction and Figure 7 The electrodes are arranged sequentially in the left-right direction (specifically, the width direction of electrode 100).

[0147] This design increases the contact area between the tab protector and the active material layer 2 at multiple locations, further enhancing the adhesion of the tab protector at those locations. This ensures better protection for the tab 200, resulting in higher battery safety. Furthermore, it increases the loading capacity of the active material layer 2, thus further guaranteeing battery capacity.

[0148] In some embodiments, refer to Figure 6 and Figure 7 As shown, in the direction toward the groove 3, the projection width h of the protrusion 241 on the current collector 1 gradually decreases.

[0149] Continue to refer to Figure 6 Taking the example of providing a protrusion 24 on the extension area 22 on the right side of the groove 3, the direction near the groove 3 can be... Figure 6 The direction from right to left and Figure 7 From bottom to top, that is to say, in Figure 6 In the direction from right to left, the projected width h of the protrusion 241 gradually decreases along the vertical direction; Figure 7 In the top-to-bottom direction, the projection width h of the protrusion 241 gradually decreases along the left-right direction.

[0150] This design creates a serrated protrusion 24, which increases the adhesion between the tab protective adhesive and the active material layer 2, while also ensuring the connection strength of the tab 200 at the groove 3 to a certain extent.

[0151] In some embodiments, the projection width h of the protrusion 241 on the current collector 1 satisfies: 100μm≤h≤1500μm.

[0152] For example, the projection width h can be 100μm, 200μm, 400μm, 600μm, 800μm, 1000μm, 1200μm, 1300μm, 1400μm, or 1500μm.

[0153] By setting the projection width h within the above range, the number of protrusions 241 at the groove 3 can be increased to a certain extent, that is, the frequency of protruding paste application can be guaranteed, thereby further increasing the bonding area between the tab protective adhesive and the active material layer 2, thereby enhancing the bonding performance of the two and further ensuring the safety of the battery.

[0154] In some embodiments, refer to Figure 7 As shown, a recess 242 is formed between two adjacent protrusions 241. The distance L between the projection of the end of the protrusion 241 near the groove 3 on the current collector 1 and the projection of the end of the recess 242 away from the groove 3 on the current collector 1 satisfies: 20μm≤L≤2000μm.

[0155] Reference Figure 7 As shown, the end of the protrusion 241 closest to the groove 3 can be the upper end of the protrusion 241, and the end of the recess 242 furthest from the groove 3 can be the lower end of the recess 242. Specifically, the distance L can be the distance between the upper end of the protrusion 241 and the lower end of the adjacent recess 242. Figure 7 The distance in the vertical direction.

[0156] For example, the distance L can be 20μm, 100μm, 400μm, 800μm, 1000μm, 1010μm, 1200μm, 1400μm, 1600μm, 1800μm, or 2000m.

[0157] By setting the distance L within the above range, the bonding area between the tab protective adhesive and the active material layer 2 can be further increased, thereby enhancing the bonding performance of both and further enhancing the safety of the battery. Moreover, this can also, to a certain extent, prevent the protrusion 241 from being too long and contacting the connection area of ​​the tab 200, thus affecting the connection strength and stability of the tab 200, thereby further ensuring the connection strength and stability of the tab 200.

[0158] In some embodiments, the angle s between the line connecting the end of the protrusion 241 near the groove 3 and the end of the two adjacent recesses 242 away from the groove 3 satisfies: 30°≤s≤75°. For example, the angle s can be 30°, 35°, 40°, 45°, 50°, 52.5°, 55°, 60°, 65°, 70°, or 75°.

[0159] Reference Figure 7 As shown, the aforementioned included angle s can specifically be the included angle s formed by the lines connecting the lower ends of two adjacent recesses 242 to the upper ends of the protrusion 241 located between the two recesses 242.

[0160] By setting the included angle s within the above range, the number of protrusions 241 at the groove 3 can be increased to a certain extent, that is, the frequency of protruding paste application can be guaranteed, thereby increasing the bonding area between the tab protective adhesive and the active material layer 2 to a certain extent, ensuring the bonding performance of the two, and further enhancing the safety of the battery.

[0161] In some embodiments, refer to Figure 6 As shown, along the third direction, a notch 121 is formed on one side edge of the portion of the current collector 1 corresponding to the groove 3.

[0162] For example, refer to Figure 6 Specifically, the notch 121 can be located at the upper edge of the empty foil area 12. In practice, the tab 200 extends from the upper edge of the empty foil area 12.

[0163] With this configuration, the thickness of the electrode 100 at that location is reduced due to the presence of the notch 121, thereby reducing the thickness of the battery cell and increasing the energy density per unit volume of the battery cell.

[0164] For example, the notch 121 can be punched out at the aforementioned location of the current collector 1 by a process such as punching.

[0165] In some embodiments, refer to Figure 8 As shown, when the groove 3 is located on the first side 13, the area on the second side 14 corresponding to the groove 3 is not coated with the active material layer 2.

[0166] For example, refer to Figure 8 Specifically, this refers to the second side 14 of the empty foil area 12 along the first direction where the active material layer 2 is not coated.

[0167] This arrangement can, to a certain extent, ensure that the two sides of the current collector 1 at groove 3 (i.e., the empty foil area 12) are within the current collector. Figure 8The active material layer 2 is not coated on either the upper or lower side of the current collector 1, thus forming a double-sided empty foil area. Compared with the scheme of coating the active material layer on the area corresponding to the groove on the second side, this can avoid the situation of powder falling off the area corresponding to the groove 3 on the second side 14 when the tab 200 is connected.

[0168] Furthermore, the region of the uncoated active material layer 2 on the second side 14 has a misalignment gap F between the projected edge of the groove 3 in the second direction and the projected edge of the groove 3 in the second direction.

[0169] Continue to refer to Figure 8 For example, the left edge of the upper side of the empty foil area 12 and the left side wall of the groove 3 may be offset from each other in the left-right direction to form the above-mentioned misalignment distance F, and the right edge of the upper side of the empty foil area 12 and the right side inner wall of the groove 3 may be offset from each other in the left-right direction to form the above-mentioned misalignment distance F.

[0170] By setting the aforementioned misalignment spacing F, powder shedding in the area corresponding to the groove 3 on the second side 14 can be further avoided when the tab 200 is connected. Moreover, due to the existence of the misalignment spacing F, the thickness of the electrode 100 at the corresponding position can be further reduced, thereby reducing the thickness of the battery cell and ensuring the energy density per unit volume of the battery cell.

[0171] In some embodiments, the misalignment distance F satisfies: F≤0.5mm. For example, the misalignment distance F can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, or 0.5mm.

[0172] By setting the misalignment spacing F within the aforementioned range, powder is prevented from falling off the area of ​​the second side 14 corresponding to the groove 3 when the tab 200 is connected, and the thickness of the electrode 100 at the corresponding position of the tab 200 is reduced to ensure the unit volume energy density of the cell. At the same time, this also ensures that the area of ​​the second side 14 without the active material layer 2 and the projection edge of the groove 3 in the second direction are not misaligned too much, thus avoiding the situation where excessive misalignment affects the load of the active material layer 2. This can, to a certain extent, ensure the load of the active material layer 2, thereby ensuring the battery capacity.

[0173] In some embodiments, the groove 3 includes two side groove walls 31 disposed opposite to each other along a second direction and a bottom wall 32 connected between the two side groove walls 31; in the second direction, the boundary of the adhesive layer is located between the edge of the tab 200 and the side groove wall 31. In some examples, in the third direction, the boundary of the adhesive layer is located between the edge of the tab 200 and the bottom wall 32, thereby ensuring the bonding strength and current density between the tab and the current collector. At the same time, the boundary of the adhesive layer extends beyond the edge of the tab, and the exposed part reacts with the electrolyte, thereby playing a role similar to a barrier, preventing the conductive adhesive layer under the tab from failing and causing the tab and the current collector to separate.

[0174] In some examples, the maximum thickness of the adhesive layer along the first direction is 10-30 micrometers.

[0175] This embodiment also provides a battery cell, including a first electrode and a second electrode.

[0176] In this design, the first and second electrodes have opposite polarities. For example, if the first electrode is a positive electrode, the current collector 1 could be aluminum foil, and the active material layer 2 could be made of positive electrode active materials such as lithium cobalt oxide, ternary materials, lithium iron phosphate, lithium carbonate, or lithium manganese oxide. Conversely, if the second electrode is a negative electrode, the current collector 1 could be copper foil, and the active material layer 2 could be made of negative electrode active materials such as graphite or silicon. Of course, the first electrode can also be a negative electrode, and the second electrode can also be a positive electrode.

[0177] Among them, at least one of the positive electrode and the negative electrode has the same structure and implementation principle as the electrode 100 provided in the above embodiments, and can bring the same or similar technical effects. They will not be described in detail here, but can be referred to the description of the above embodiments.

[0178] This embodiment also provides a battery, which may include a cell and a casing, with the casing covering the outside of the cell. The battery may be, for example, a lithium-ion battery.

[0179] Batteries can be used as power sources or energy storage units for electronic devices, which may include, but are not limited to, mobile devices (mobile phones, laptops, tablets, etc.) and electric vehicles (such as pure electric vehicles, hybrid electric vehicles, electric bicycles, etc.).

[0180] The battery cell in this embodiment has the same structure and implementation principle as the battery cell provided in the above embodiments, and can bring the same or similar technical effects. It will not be described in detail here. For details, please refer to the description of the above embodiments.

[0181] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection or an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, the terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component 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 application.

[0182] In this document, relational terms such as “first” and “second” are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0183] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications or equivalent substitutions made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A pole piece, characterized in that, The electrode tab comprises a current collector (1), an active material layer (2) and a tab (200); The active material layer (2) is arranged on at least one side of the current collector (1), and the active material layer (2) comprises a groove (3) exposing the current collector (1); the tab (200) is located in the groove (3) and is electrically connected with the current collector (1); The active material layer (2) located on the side of the groove (3) comprises a main area (21) and an extension area (22) located on the side of the main area (21) close to the groove (3); a side wall of the extension area (22) away from the main area (21) surrounds the groove (3); the thickness of the extension area (22) in the first direction is less than the thickness of the main area (21) in the first direction; the tab further comprises a glue layer bonded between the tab (200) and the current collector (1).

2. The pole piece of claim 1, wherein The groove (3) comprises two side groove walls (31) oppositely arranged in the second direction and a groove bottom wall (32) connected between the two side groove walls (31); The included angle α between the side groove wall (31) and the groove bottom wall (32) satisfies 90°≤α≤160°; And / or, the groove (3) comprises two side groove walls (31) oppositely arranged in the second direction and a groove bottom wall (32) connected between the two side groove walls (31); The side groove wall (31) and the groove bottom wall (32) are smoothly transitioned through an arc-shaped wall (33).

3. The pole piece of any one of claims 1 to 2, wherein, In the direction away from the main area (21), the thickness of the extension area (22) in the first direction gradually decreases; And / or, the side surface of the extension area (22) away from the current collector (1) is an arc surface (23); And / or, the included angle β between the side surface of the extension area (22) away from the current collector (1) and the current collector (1) satisfies 3°≤β≤80°; And / or, in the direction from the main area (21) to the extension area (22), the length E of the extension area (22) satisfies 0.5mm≤E≤10mm; And / or, in the second direction, the thickness of the main area (21) located on one side of the groove (3) is not greater than the thickness of the main area (21) located on the other side of the groove (3).

4. The pole piece according to any one of claims 1 to 2, characterized in that The side of the extension area (22) close to the groove (3) is provided with a protruding part (24) extending towards the direction of the groove (3).

5. The pole piece of claim 4, wherein In the direction close to the groove (3), the maximum length c of the projection of the protruding part (24) on the current collector (1) satisfies c≤2mm; And / or, the protruding part (24) is arranged on the extension area (22) located on at least one side of the groove (3) in the second direction; the ratio of the maximum length c of the projection of the protruding part (24) in the second direction to the groove width D of the groove (3) in the second direction satisfies c / D≤1 / 3.

6. The pole piece of claim 4, wherein The protrusion (24) comprises at least two protrusions (241) arranged in sequence, each of the protrusions (241) extends towards the direction of the groove (3).

7. The pole piece of claim 6, wherein In the direction towards the groove (3), the projection width h of the protrusion (241) on the current collector (1) gradually decreases; And / or, in the direction towards the groove (3), the projection width h of the protrusion (241) on the current collector (1) satisfies: 100μm≤h≤1500μm; And / or, a recess (242) is formed between two adjacent protrusions (241), and among the protrusion (241) and the recess (242), the distance L between the projection of the end of the protrusion (241) close to the groove (3) on the current collector (1) and the projection of the end of the recess (242) away from the groove (3) on the current collector (1) satisfies: 20μm≤L≤2000μm; And / or, among the protrusion (241) and two adjacent recesses (242), the included angle s between the line connecting the end of the protrusion (241) close to the groove (3) and the ends of the two recesses (242) away from the groove (3) satisfies: 30°≤s≤75°.

8. The pole piece of any one of claims 1 to 2, wherein, In the third direction, a notch (121) is formed on one side edge of the part of the current collector (1) corresponding to the groove (3); And / or, in the first direction, the current collector (1) has opposite first side (13) and second side (14), the groove (3) is located on the first side (13), and the region of the second side (14) corresponding to the groove (3) is not coated with the active material layer (2); The projection edge of the region of the second side (14) not coated with the active material layer (2) in the second direction has a misalignment distance F with the projection edge of the groove (3) in the second direction; The misalignment distance F satisfies: F≤0.5mm; And / or, in the first direction, the current collector (1) has opposite first side (13) and second side (14), the groove (3) is located on the first side (13), and the projection of the groove (3) in the thickness direction of the current collector overlaps with the projection of the active material layer (2) on the second side (14).

9. The pole piece of claim 1, wherein, The groove (3) comprises two side groove walls (31) oppositely arranged in the second direction and a groove bottom wall (32) connected between the two side groove walls (31); In the second direction, the boundary of the adhesive layer is located between the edge of the tab (200) and the side groove wall (31), and / or In the third direction, the boundary of the adhesive layer is located between the edge of the tab (200) and the groove bottom wall (32); and / or In the first direction, the maximum thickness of the adhesive layer is 10-30 microns.

10. An electric cell characterized by Comprising a first tab and a second tab; At least one of the first tab and the second tab is the tab as claimed in any one of claims 1 to 9.

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