Cells, batteries and electrical equipment

Abstract

A battery cell includes a first pole piece. The first pole piece includes a first current collector and a first active material layer. The first current collector includes a first surface. The first active material layer includes a first part and a second part, the first part and the second part are arranged on the first surface at intervals along a first direction, and a first groove exposing the first surface is formed between the first part and the second part. Along the first direction, a portion of the first part adjacent to the first groove is provided with a first thinning area, and a portion of the second part adjacent to the first groove is provided with a second thinning area. Along the second direction, the thickness of the second thinning area is greater than the thickness of the first thinning area. The battery cell also includes a first glue layer, the first glue layer is bonded to the first thinning area and extends from the first thinning area to the second thinning area, and a portion of the first glue layer covers the first groove. The present application also provides a battery and an electrical device provided with a battery cell, which can reduce the risk of lithium plating.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] In the production process of batteries, a tab groove is usually set in the active material layer of the pole piece, and the tab is fixed in the long tab groove to reduce the accumulation of tab thickness. The tab groove is generally made by gap coating. Due to the different thinning mechanisms of the head and tail, the thinning of the head is more difficult to control than the thinning of the tail, so that at least one of the active material layers on both sides of the tab groove has an abnormal thickness, resulting in lithium deposition at this position. Summary of the invention

[0003] In view of the above situation, it is necessary to provide a battery cell to reduce the risk of lithium plating.

[0004] An embodiment of the present application provides a battery cell, including a first pole piece. The first pole piece includes a first current collector and a first active material layer. The first current collector includes a first surface. The first active material layer includes a first part and a second part, the length direction of the first current collector after unfolding is a first direction, the first part and the second part are arranged on the first surface at intervals along the first direction, and a first groove exposing the first surface is formed between the first part and the second part. Along the first direction, a portion of the first part adjacent to the first groove is provided with a first thinning area, and a portion of the second part adjacent to the first groove is provided with a second thinning area. The thickness direction of the first current collector is a second direction, and along the second direction, the thickness of the second thinning area is greater than the thickness of the first thinning area. The battery cell also includes a first glue layer, the first glue layer is bonded to the first thinning area and extends from the first thinning area to the second thinning area, and part of the first glue layer covers the first groove. Along the first direction, the length L1 of the first glue layer bonded to the first thinning area is less than the length L2 of the first glue layer bonded to the second thinning area.

[0005] Compared with the existing method of having the same length of glue on both sides of the groove, L1<L2, which can increase the area of ​​the first glue layer covering the second thinned area while ensuring that the first glue layer completely covers both sides of the first groove along the first direction, thereby reducing the risk of lithium deposition in the second thinned area and reducing the area of ​​the first glue layer covering the first thinned area, thereby improving the energy density of the battery.

[0006] In some embodiments of the present application, 0mm<L1≤5mm, 0.5mm≤L2≤20mm.

[0007] In some embodiments of the present application, the first pole piece further includes a second active material layer. The first current collector further includes a second surface, and the second surface and the first surface are arranged opposite to each other along the second direction. The second active material layer includes a third part and a fourth part. The third part and the fourth part are arranged on the second surface at intervals along the first direction, and a second groove exposing the second surface is formed between the third part and the fourth part. Along the first direction, a portion of the third part adjacent to the second groove is provided with a third thinning area, and a portion of the fourth part adjacent to the second groove is provided with a fourth thinning area. Along the second direction, the thickness of the third thinning area is greater than the thickness of the fourth thinning area. The battery cell further includes a second glue layer, the second glue layer is bonded to the third thinning area and extends from the third thinning area to the fourth thinning area, and a portion of the second glue layer covers the second groove. Along the first direction, the length L3 of the second glue layer bonded to the third thinning area is greater than the length L4 of the second glue layer bonded to the fourth thinning area.

[0008] Compared with the existing method of having the same length of glue on both sides of the groove, L3>L4, which can increase the area of ​​the second groove covering the third thinning zone while ensuring that the second glue layer completely covers both sides of the second groove along the first direction, thereby reducing the risk of lithium deposition in the third thinning zone and reducing the area of ​​the second glue layer covering the fourth thinning zone, thereby improving the energy density of the battery.

[0009] In some embodiments of the present application, 0.5mm≤L3≤20mm, 0mm<L4≤5mm.

[0010] In some embodiments of the present application, along the second direction, the third thinned area is opposite to the first thinned area, and the fourth thinned area is opposite to the second thinned area, so that the first adhesive layer and the second adhesive layer are staggered in the first direction.

[0011] In some embodiments of the present application, along the second direction, the projection of the first groove and the projection of the second groove are arranged to overlap, so as to facilitate positioning of the first groove and the second groove during the preparation process of the first pole piece, simplify the preparation process of the pole piece, and improve production efficiency.

[0012] In some embodiments of the present application, L2=L3, which may further limit the first adhesive layer and the second adhesive layer to be staggered in the first direction.

[0013] In some embodiments of the present application, the difference between the length L1 of the first adhesive layer bonded to the first thinned area and the length L3 of the second adhesive layer bonded to the third thinned area is A, 1mm<|A|<15mm. When |A|≤1mm, the two are basically aligned and glued, which is consistent with the existing glue sticking method. On the premise that the second adhesive layer covers the third thinned area, the area of ​​the first adhesive layer covering the first thinned area will increase, thereby causing a loss in the energy density of the battery. When |A|≥15mm, the two are too misaligned. On the premise that the first adhesive layer covers the first thinned area, the second adhesive layer may be in other normal areas of the third part, thereby causing a loss in the energy density of the battery.

[0014] In some embodiments of the present application, the difference between the length L2 of the first adhesive layer bonded to the second thinned area and the length L4 of the second adhesive layer bonded to the fourth thinned area is B, 1mm<|B|<15mm. When |B|≤1mm, the two are basically aligned and glued, which is consistent with the existing glue sticking method. On the premise that the first adhesive layer covers the second thinned area, the area of ​​the fourth thinned area covered by the second adhesive layer will increase, thereby causing a loss in the energy density of the battery. When |B|≥15mm, the two are too misaligned. On the premise that the second adhesive layer covers the fourth thinned area, the first adhesive layer may be in other normal areas of the second part, thereby causing a loss in the energy density of the battery.

[0015] In some embodiments of the present application, the first electrode plate is a positive electrode plate or a negative electrode plate.

[0016] An embodiment of the present application further provides a battery, comprising a housing and a battery cell according to any of the above embodiments, wherein the battery cell is disposed in the housing.

[0017] An embodiment of the present application further provides an electrical device, comprising the battery in any of the above embodiments.

[0018] In the battery cell, battery and electrical equipment of the present application, along the first direction, the length of the first adhesive layer bonded to the first thinned area is less than the length of the first adhesive layer bonded to the second thinned area. Compared with the existing method of having the same adhesive length on both sides of the groove, L1<L2, while satisfying that the first adhesive layer completely covers both sides of the first groove along the first direction, the area of ​​the second thinned area covered by the first adhesive layer is increased, the risk of lithium deposition in the second thinned area is reduced, and the area of ​​the first adhesive layer covering the first thinned area is reduced, thereby improving the energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a first structural schematic diagram of a battery cell according to an embodiment of the present application.

[0020] Figure 2 It is a first structural schematic diagram of the first pole piece in a battery cell of an embodiment of the present application.

[0021] Figure 3 It is a second structural schematic diagram of a battery cell according to an embodiment of the present application.

[0022] Figure 4 It is a second structural schematic diagram of the first pole piece in a battery cell of an embodiment of the present application.

[0023] Figure 5 It is a third structural schematic diagram of a battery cell according to an embodiment of the present application.

[0024] Figure 6 It is a schematic diagram of the structure of the first pole piece and the second pole piece in a battery cell of an embodiment of the present application.

[0025] Figure 7 It is a schematic diagram of the structure of an electrical device according to an embodiment of the present application.

[0026] Main component symbols

[0027] Battery Cell 100

[0028] Battery 200

[0029] Electrical equipment 300

[0030] The first pole piece 10

[0031] The first current collector 11

[0032] First surface 11a

[0033] Second surface 11b

[0034] Blank Area 111

[0035] First active material layer 12

[0036] Part 121

[0037] The first thinned area 121a

[0038] Part 2122

[0039] The second thinned area 122a

[0040] First groove 13

[0041] The second active material layer 14

[0042] Part III141

[0043] The third thinned area 141a

[0044] Part 4142

[0045] Fourth thinned area 142a

[0046] Second groove 15

[0047] The second pole piece 20

[0048] Isolation film 30

[0049] The first adhesive layer 41

[0050] Second adhesive layer 42

[0051] The third adhesive layer 51

[0052] Fourth adhesive layer 52

[0053] First tab 61

[0054] Second pole ear 62

[0055] Equipment body 90

[0056] First direction X

[0057] The second direction Z

[0058] The third direction Y

[0059] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0061] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centrally disposed element at the same time. When an element is considered to be "disposed on" another element, it may be directly disposed on the other element or there may be a centrally disposed element at the same time.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art belonging to the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items. The terms "vertical", "horizontal", "left", "right", "top", "bottom" and similar expressions used herein are only for illustrative purposes and are not intended to limit the present application.

[0063] It can be understood that when two elements are arranged parallel / vertically and in the same direction, there may be a certain angle between the two elements, a tolerance of 0-±10% is allowed between the two elements, and a tolerance of 0-±10% is allowed between the two elements greater than, equal to or less than.

[0064] The present application relates to a thinning zone of an active material layer. The following is a brief description of the thinning zone involved in the present application: During the production process of the battery, the coating liquid is usually applied to the current collector by extrusion coating to form an active material layer. As needed, some positions of the current collector do not need to be coated with the coating liquid, and intermittent coating can be used for coating. Intermittent coating can be controlled by a coating valve, which is applied by alternately opening and closing the coating valve. From the moment the coating valve is opened to the time when the coating liquid flows out stably, the coating liquid applied to the current collector is unstable. At this time, the area formed by the coating liquid applied to the current collector is called a thinning zone. The thickness of the thinning zone is generally lower than the thickness of the normal zone.

[0065] In addition, due to the intermittent opening and closing moments, the hydraulic pressure of the coating liquid in the pipeline will be unstable, and inconsistent thickness at the head and tail will often occur.

[0066] An embodiment of the present application provides a battery cell, including a first pole piece. The first pole piece includes a first current collector and a first active material layer. The first current collector includes a first surface. The first active material layer includes a first part and a second part, the length direction of the first current collector after unfolding is a first direction, the first part and the second part are arranged on the first surface along the first direction, and a first groove exposing the first surface is formed between the first part and the second part. Along the first direction, a portion of the first part adjacent to the first groove is provided with a first thinning area, and a portion of the second part adjacent to the first groove is provided with a second thinning area. The thickness direction of the first current collector is a second direction, and along the second direction, the thickness of the second thinning area is greater than the thickness of the first thinning area. The battery cell also includes a first glue layer, the first glue layer is bonded to the first thinning area and extends from the first thinning area to the second thinning area, and part of the first glue layer covers the first groove. Along the first direction, the length L1 of the first glue layer bonded to the first thinning area is less than the length L2 of the first glue layer bonded to the second thinning area.

[0067] In the above-mentioned battery cell, compared with the existing method of having the same length of glue on both sides of the groove, L1<L2, which can increase the area of ​​the first glue layer covering the second thinned area while ensuring that the first glue layer completely covers both sides of the first groove along the first direction, thereby reducing the risk of lithium deposition in the second thinned area, and can also reduce the area of ​​the first glue layer covering the first thinned area, thereby improving the energy density of the battery.

[0068] The embodiments of the present application are further described with reference to the accompanying drawings.

[0069] Please also read Figure 1 and Figure 2 One embodiment of the present application provides a battery cell 100, comprising a first pole piece 10, a second pole piece 20 and a separator 30. The separator 30 is located between the first pole piece 10 and the second pole piece 20. The polarities of the first pole piece 10 and the second pole piece 20 are opposite. In some embodiments, the first pole piece 10, the second pole piece 20 and the separator 30 are wound in sequence.

[0070] It can be understood that, in some embodiments, the first pole piece 10 , the second pole piece 20 and the isolation film 30 are stacked in sequence.

[0071] In some embodiments, the first electrode sheet 10 includes a first current collector 11 and a first active material layer 12. The first current collector 11 includes a first surface 11a. The first active material layer 12 can allow lithium ions to be extracted and inserted. The first current collector 11 conducts the current generated by the electrochemical reaction to an external circuit, thereby realizing the process of converting chemical energy into electrical energy.

[0072] The first active material layer 12 includes a first part 121 and a second part 122. The length direction of the first current collector 11 after unfolding is the first direction X, and the width direction of the first current collector 11 after unfolding is the third direction Y. The "length direction" and "width direction" of the first current collector 11 refer to the two dimensions of the surface of the first current collector 11, respectively. The length direction refers to the main dimension direction (i.e., the direction of the larger size), and the width direction refers to the secondary dimension direction (i.e., the direction of the smaller size). Generally, the length direction is consistent with the coating direction of the first active material layer 12, and is also consistent with the winding direction. The width direction is set perpendicular to the length direction.

[0073] The first portion 121 and the second portion 122 are spaced apart from each other on the first surface 11a along the first direction X, and a first groove 13 exposing the first surface 11a is formed between the first portion 121 and the second portion 122. The first groove 13 is provided through the third direction Y. The first groove 13 is used to accommodate components such as a tab, and the portion of the first surface 11a located in the first groove 13 is used to be electrically connected to components such as a tab.

[0074] Along the first direction X, the first portion 121 adjacent to the first groove 13 is provided with a first thinned area 121a.

[0075] The second portion 122 is provided with a second thinned area 122a at a portion adjacent to the first groove 13. The thickness direction of the first current collector 11 is the second direction Z. Along the second direction Z, the thickness of the first thinned area 121a is less than the thickness of other normal areas of the first portion 121, and the thickness of the second thinned area 122a is less than the thickness of other normal areas of the second portion 122. And the thickness of the second thinned area 122a is greater than the thickness of the first thinned area 121a.

[0076] The battery cell 100 further includes a first adhesive layer 41, which is bonded to the first thinned area 121a and extends from the first thinned area 121a to the second thinned area 122a, and a portion of the first adhesive layer 41 covers the first groove 13. Specifically, along the second direction Z, the projection of the first thinned area 121a, the projection of the first groove 13, and the projection of the second thinned area 122a are all located within the projection range of the first adhesive layer 41.

[0077] The portion of the first adhesive layer 41 bonded to the first thinned area 121a is used to insulate and isolate the first thinned area 121a from the area of ​​the second pole piece 20 facing the first thinned area 121a, so as to reduce the risk of lithium deposition in the first thinned area 121a. The portion of the first adhesive layer 41 covering the first groove 13 is used to insulate and isolate the first surface 11a exposed in the first groove 13 and the components connected to the first groove 13. The portion of the first adhesive layer 41 bonded to the second thinned area 122a is used to insulate and isolate the second thinned area 122a from the area of ​​the second pole piece 20 facing the second thinned area 122a, so as to reduce the risk of lithium deposition in the second thinned area 122a.

[0078] Since the thickness of the second thinned area 122a is greater than that of the first thinned area 121a, the second thinned area 122a can provide more lithium ions during the charge and discharge process, making it easier for the second thinned area 122a to produce lithium deposition. Along the first direction X, the length L1 of the first adhesive layer 41 bonded to the first thinned area 121a is less than the length L2 of the first adhesive layer 41 bonded to the second thinned area 122a. Compared with the existing method of having the same adhesive length on both sides of the groove, L1<L2, while satisfying that the first adhesive layer 41 completely covers both sides of the first groove 13 along the first direction X, the area of ​​the first adhesive layer 41 covering the second thinned area 122a is increased, the risk of lithium deposition in the second thinned area 122a is reduced, and the area of ​​the first adhesive layer 41 covering the first thinned area 121a is reduced, thereby improving the energy density of the battery. In addition, the use amount of the first adhesive layer 41 can be reduced, thereby reducing production costs.

[0079] In some embodiments, 0mm<L1≤5mm. Optionally, L1 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, and any other value within the range. 0.5mm≤L2≤20mm. Optionally, L2 can be 0.5mm, 1mm, 2.5mm, 5mm, 7.5mm, 10mm, 12.5mm, 15mm, 17.5mm, 20mm, and any other value within the range.

[0080] Please continue reading Figure 1 and Figure 2In some embodiments, the first electrode sheet 10 further includes a second active material layer 14. The first current collector 11 further includes a second surface 11b. The second surface 11b and the first surface 11a are arranged opposite to each other along the second direction Z. The second active material layer 14 has the same polarity as the first active material layer 12, and can allow lithium ions to be extracted and embedded.

[0081] The second active material layer 14 includes a third portion 141 and a fourth portion 142, which are arranged at intervals on the second surface 11b along the first direction X, and a second groove 15 exposing the second surface 11b is formed between the third portion 141 and the fourth portion 142. The second groove 15 is used to accommodate components such as a tab, and the portion of the second surface 11b located in the second groove 15 is used to be electrically connected to components such as a tab.

[0082] Along the first direction X, the third portion 141 is adjacent to the second groove 15 and has a third thinned area 141a, and the fourth portion 142 is adjacent to the second groove 15 and has a fourth thinned area 142a. Along the second direction Z, the thickness of the third thinned area 141a is greater than that of the fourth thinned area 142a.

[0083] The battery cell 100 further includes a second adhesive layer 42, which is bonded to the third thinned area 141a and extends from the third thinned area 141a to the fourth thinned area 142a, and a portion of the second adhesive layer 42 covers the second groove 15. Specifically, along the second direction Z, the projection of the third thinned area 141a, the projection of the second groove 15, and the projection of the fourth thinned area 142a are all located within the projection range of the second adhesive layer 42.

[0084] The portion of the second adhesive layer 42 bonded to the third thinned area 141a is used to insulate and isolate the third thinned area 141a from the area of ​​the second pole piece 20 facing the third thinned area 141a, so as to reduce the risk of lithium deposition in the third thinned area 141a. The portion of the second adhesive layer 42 covering the second groove 15 is used to insulate and isolate the second surface 11b exposed in the second groove 15 and the components connected to the second groove 15. The portion of the second adhesive layer 42 bonded to the fourth thinned area 142a is used to insulate and isolate the fourth thinned area 142a from the area of ​​the second pole piece 20 facing the fourth thinned area 142a, so as to reduce the risk of lithium deposition in the fourth thinned area 142a.

[0085] Since the thickness of the third thinned area 141a is greater than that of the fourth thinned area 142a, the third thinned area 141a can provide more lithium ions during the charge and discharge process, making it easier for the third thinned area 141a to produce lithium deposition. Along the first direction X, the length L3 of the second adhesive layer 42 bonded to the third thinned area 141a is greater than the length L4 of the second adhesive layer 42 bonded to the fourth thinned area 142a. Compared with the existing method of having the same adhesive length on both sides of the groove, L3>L4, while satisfying that the second adhesive layer 42 completely covers both sides of the second groove 15 along the first direction X, the area of ​​the second groove 15 covering the third thinned area 141a is increased, reducing the risk of lithium deposition in the third thinned area 141a, and can also reduce the area of ​​the second adhesive layer 42 covering the fourth thinned area 142a, thereby improving the energy density of the battery.

[0086] In some embodiments, 0.5 mm ≤ L3 ≤ 20 mm. Optionally, L3 may be 0.5 mm, 1 mm, 2.5 mm, 5 mm, 7.5 mm, 10 mm, 12.5 mm, 15 mm, 17.5 mm, 20 mm, and any other value within the range. 0 mm < L4 ≤ 5 mm. Optionally, L4 may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, and any other value within the range.

[0087] Please continue reading Figure 1 and Figure 2 In some embodiments, along the second direction Z, the third thinning area 141a is opposite to the first thinning area 121a, and the fourth thinning area 142a is opposite to the second thinning area 122a, so that the first adhesive layer 41 and the second adhesive layer 42 are staggered in the first direction X. Specifically, along the first direction X, the portion of the second adhesive layer 42 bonded to the third thinning area 141a exceeds the portion of the first adhesive layer 41 bonded to the first thinning area 121a, and the portion of the first adhesive layer 41 bonded to the second thinning area 122a exceeds the portion of the second adhesive layer 42 bonded to the fourth thinning area 142a. Compared with the existing alignment glue sticking method, reducing the area of ​​the first adhesive layer 41 covering the first thinning area 121a and reducing the area of ​​the second adhesive layer 42 covering the fourth thinning area 142a can reduce the risk of lithium plating while improving the energy density of the battery.

[0088] Please continue reading Figure 1 and Figure 2In some embodiments, along the second direction Z, the projection of the first groove 13 and the projection of the second groove 15 are arranged to overlap, so as to facilitate the positioning of the first groove 13 and the second groove 15 during the preparation process of the first pole piece 10, simplify the preparation process of the pole piece, and improve production efficiency. Specifically, along the first direction X, the third thinning area 141a and the first thinning area 121a are located on one side of the first groove 13, and the fourth thinning area 142a and the second thinning area 122a are located on the other side of the first groove 13. It can be understood that the second groove 15 can also replace the first groove 13 as a reference, the third thinning area 141a and the first thinning area 121a are located on one side of the second groove 15, and the fourth thinning area 142a and the second thinning area 122a are located on the other side of the second groove 15.

[0089] In some embodiments, L2=L3, and / or L1=L4. When L2=L3 and L1=L4, it can be further defined that the first adhesive layer 41 and the second adhesive layer 42 are staggered in the first direction X.

[0090] Please continue reading Figure 1 and Figure 2 In some embodiments, the difference between the length L1 of the first adhesive layer 41 bonded to the first thinned area 121a and the length L3 of the second adhesive layer 42 bonded to the third thinned area 141a is A, 1mm<|A|<15mm. When |A|≤1mm, the two are basically aligned and glued, which is consistent with the existing glue sticking method. On the premise that the second adhesive layer 42 covers the third thinned area 141a, the area covered by the first adhesive layer 41 in the first thinned area 121a will increase, thereby causing a loss in the energy density of the battery. When |A|≥15mm, the two are too misaligned. On the premise that the first adhesive layer 41 covers the first thinned area 121a, the second adhesive layer 42 may be in other normal areas of the third part 141, thereby causing a loss in the energy density of the battery.

[0091] Optionally, |A| can be 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14.5mm, and any other value within the range.

[0092] In some embodiments, the difference between the length L2 of the first adhesive layer 41 bonded to the second thinned area 122a and the length L4 of the second adhesive layer 42 bonded to the fourth thinned area 142a is B, 1mm<|B|<15mm. When |B|≤1mm, the two are basically aligned and glued, which is consistent with the existing glue sticking method. On the premise that the first adhesive layer 41 covers the second thinned area 122a, the area covered by the second adhesive layer 42 in the fourth thinned area 142a will increase, thereby causing a loss in the energy density of the battery. When |B|≥15mm, the two are too misaligned. On the premise that the second adhesive layer 42 covers the fourth thinned area 142a, the first adhesive layer 41 may be in other normal areas of the second part 122, thereby causing a loss in the energy density of the battery.

[0093] Optionally, |B| can be 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14.5mm, and any other value within the range.

[0094] Please continue reading Figure 1 and Figure 2 In some embodiments, the battery cell 100 further includes a first pole tab 61, at least a portion of which is located in the first groove 13 or the second groove 15, and is electrically connected to the first current collector 11. Specifically, at least a portion of the first pole tab 61 is electrically connected to a portion of the first surface 11a located in the first groove 13; or at least a portion of the first pole tab 61 is electrically connected to a portion of the second surface 11b located in the second groove 15. The first groove 13 or the second groove 15 accommodates the first pole tab 61, thereby improving the stability of the electrical connection.

[0095] In some embodiments, the battery cell 100 also includes a third adhesive layer 51, which is bonded to the area of ​​the second pole piece 20 facing the first adhesive layer 41, so that the area covered by the first adhesive layer 41 on the first pole piece 10 and the area of ​​the second pole piece 20 facing the first adhesive layer 41 are insulated and isolated from each other, thereby reducing the risk of lithium plating.

[0096] In some embodiments, along the first direction X, both sides of the third adhesive layer 51 extend beyond both sides of the first adhesive layer 41, so that when displacement occurs between the first pole piece 10 and the second pole piece 20 in the event of a collision of the battery cell 100, etc., the third adhesive layer 51 can still play an insulating isolation role, thereby improving the stability of insulation.

[0097] In some embodiments, the battery cell 100 also includes a fourth adhesive layer 52, which is bonded to the area of ​​the second pole piece 20 facing the second adhesive layer 42, so that the area covered by the second adhesive layer 42 on the first pole piece 10 and the area of ​​the second pole piece 20 facing the second adhesive layer 42 are insulated and isolated from each other, thereby reducing the risk of lithium plating.

[0098] In some embodiments, along the first direction X, both sides of the fourth adhesive layer 52 extend beyond both sides of the second adhesive layer 42, so that when displacement occurs between the first pole piece 10 and the second pole piece 20 in the event of a collision of the battery cell 100, the fourth adhesive layer 52 can still function as an insulating layer, thereby improving insulation stability.

[0099] In some embodiments, the first pole piece 10 is a positive pole piece, and the second pole piece 20 is a negative pole piece.

[0100] Please also read Figure 3 and Figure 4 It can be understood that, in some embodiments, when the first pole piece 10 is a negative pole piece, the second pole piece 20 is a positive pole piece.

[0101] Please also read Figure 5 and Figure 6 It can be understood that, in some embodiments, both the positive electrode plate and the negative electrode plate adopt the structural design in the above embodiments, which can reduce the risk of lithium plating while comprehensively improving the energy density of the battery.

[0102] The present application is described below by means of specific implementation methods:

[0103] First embodiment: Please refer to Figure 1 and Figure 2 , the first pole piece 10 is a negative pole piece, the second pole piece 20 is a positive pole piece, and at least part of the first pole ear 61 is located in the second groove 15. L1 = L4 = 2mm; L2 = L3 = 9mm; |A| = |B| = 7mm. The starting end of the first current collector 11 is provided with a blank area 111 not coated with the first active material layer 12 and the second active material layer 14. Along the first direction X, the length of the blank area 111 is 15mm. The lengths of the third glue layer 51 and the fourth glue layer 52 are both 11mm.

[0104] Second embodiment: Please refer to Figure 3 and Figure 4 , the first pole piece 10 is a positive pole piece, the second pole piece 20 is a negative pole piece, and at least part of the first pole ear 61 is located in the first groove 13. L1 = L4 = 2mm; L2 = L3 = 12mm; |A| = |B| = 10mm. A blank area 111 is provided at the starting end of the first current collector 11, where the first active material layer 12 and the second active material layer 14 are not coated. Along the first direction X, the length of the blank area 111 is 15mm.

[0105] Third embodiment: Please refer to Figure 5 and Figure 6The first pole piece 10 is a positive pole piece, the second pole piece 20 is a negative pole piece, and the second pole piece 20 and the first pole piece 10 have different polarities but the same structure. Taking the structure of the first pole piece 10 as an example, the structure of the second pole piece 20 can refer to the first pole piece 10, and will not be repeated here.

[0106] At least part of the first pole tab 61 is located in the second groove 15 of the first pole piece 10. L1 = L4 = 2 mm; L2 = L3 = 9 mm; |A| = |B| = 7 mm. The battery cell 100 includes a second pole tab 62, at least part of which is located in the first groove 13 of the second pole piece 20. L1 = L4 = 12 mm; L2 = L3 = 2 mm; |A| = |B| = 10 mm.

[0107] See also Figure 7 One embodiment of the present application further provides a battery 200, comprising a housing and the battery cell 100 in any of the above embodiments. The battery cell 100 is accommodated in the housing (not shown).

[0108] Please continue reading Figure 7 One embodiment of the present application further provides an electric device 300, comprising the battery 200 in the above embodiment. The electric device 300 also includes a device body 90, and the battery 200 is electrically connected to the device body 90 and supplies power to the device body 90. In some embodiments, the electric device 300 can be an electronic device such as a mobile phone, a tablet computer, or a mobile device such as an electric car.

[0109] In the above-mentioned battery cell 100, and the battery 200 and the electric device 300 provided with the battery cell 100, along the first direction X, the length L1 of the first adhesive layer 41 bonded to the first thinned area 121a is less than the length L2 of the first adhesive layer 41 bonded to the second thinned area 122a. Compared with the existing method of having the same adhesive length on both sides of the groove, L1<L2, while satisfying that the first adhesive layer 41 completely covers both sides of the first groove 13 along the first direction X, the area of ​​the first adhesive layer 41 covering the second thinned area 122a can be increased, the risk of lithium deposition in the second thinned area 122a can be reduced, and the area of ​​the first adhesive layer 41 covering the first thinned area 121a can be reduced, thereby improving the energy density of the battery.

[0110] In addition, those skilled in the art may also make other changes within the spirit of the present application. Of course, these changes made according to the spirit of the present application should be included in the scope disclosed in the present application.

Claims

1. A battery cell, comprising a first pole piece, characterized in that: The first pole piece includes a first current collector and a first active material layer, the first current collector includes a first surface, the first active material layer includes a first portion and a second portion, the length direction of the first current collector after unfolding is a first direction, the first portion and the second portion are arranged on the first surface along the first direction, and a first groove is formed between the first portion and the second portion to expose the first surface; Along the first direction, a portion of the first part adjacent to the first groove is provided with a first thinned area, a portion of the second part adjacent to the first groove is provided with a second thinned area, the thickness direction of the first current collector is the second direction, and along the second direction, the thickness of the second thinned area is greater than the thickness of the first thinned area; The battery cell further includes a first adhesive layer, the first adhesive layer is bonded to the first thinned area and extends from the first thinned area to the second thinned area, and a portion of the first adhesive layer covers the first groove, and along the first direction, a length L1 of the first adhesive layer bonded to the first thinned area is less than a length L2 of the first adhesive layer bonded to the second thinned area; 0mm<L1≤5mm, 0.5mm≤L2≤20mm.

2. The battery cell according to claim 1, characterized in that: The first pole piece further includes a second active material layer, the first current collector further includes a second surface, the second surface and the first surface are arranged opposite to each other along the second direction, the second active material layer includes a third portion and a fourth portion, the third portion and the fourth portion are arranged at intervals on the second surface along the first direction, and a second groove is formed between the third portion and the fourth portion to expose the second surface; Along the first direction, a portion of the third part adjacent to the second groove is provided with a third thinned area, a portion of the fourth part adjacent to the second groove is provided with a fourth thinned area, and along the second direction, a thickness of the third thinned area is greater than a thickness of the fourth thinned area; The battery cell also includes a second glue layer, which is bonded to the third thinned area and extends from the third thinned area to the fourth thinned area, and a portion of the second glue layer covers the second groove. Along the first direction, a length L3 of the second glue layer bonded to the third thinned area is greater than a length L4 of the second glue layer bonded to the fourth thinned area.

3. The battery cell according to claim 2, characterized in that: 0.5mm≤L3≤20mm, 0mm<L4≤5mm.

4. The battery cell according to claim 2, characterized in that: Along the second direction, the third thinned region is opposite to the first thinned region, and the fourth thinned region is opposite to the second thinned region.

5. The battery cell according to claim 2, characterized in that: Along the second direction, a projection of the first groove and a projection of the second groove are overlapped.

6. The battery cell according to claim 2, characterized in that: L2=L3.

7. The battery cell according to claim 2, characterized in that: The difference between the length L1 of the first adhesive layer bonded to the first thinned area and the length L3 of the second adhesive layer bonded to the third thinned area is A, and 1mm<|A|<15mm.

8. The battery cell according to claim 2, characterized in that: The difference between the length L2 of the first adhesive layer bonded to the second thinned area and the length L4 of the second adhesive layer bonded to the fourth thinned area is B, and 1mm<|B|<15mm.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The first pole piece is a positive pole piece or a negative pole piece.

10. A battery, comprising a housing, characterized in that: The battery further comprises a battery cell as claimed in any one of claims 1 to 9, wherein the battery cell is arranged in the housing.

11. An electrical equipment, characterized in that: Comprising the battery as claimed in claim 10.

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