Battery monomer and battery pack
By setting a barrier layer between the first coil of electrode and the separator in the first bending zone of the battery cell, the lithium plating problem caused by the gap between the electrode in the wound lithium-ion battery cell is solved, thus improving the safety and service life of the battery.
Patent Information
- Application Number
- CN202423253915.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2034-12-25
AI Technical Summary
In the wound cells of lithium-ion batteries, excessive gaps between the electrodes can lead to lithium plating, causing safety accidents such as thermal runaway.
Multiple barrier layers are set between the first coil of electrode and the separator in the first bending zone of the battery cell to form a gap, prevent lithium ions from escaping and provide support, and avoid excessive bending angle of the electrode.
Reduce lithium-ion loss, extend battery life, reduce the risk of lithium plating and thermal runaway, and avoid electrode breakage.
Smart Images
Figure CN223785157U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a battery cell and a battery pack. Background Technology
[0002] With the promotion and development of new energy technologies, lithium-ion batteries are widely used in new energy vehicles, energy storage, electric aircraft, ships and other fields.
[0003] Lithium-ion batteries can generally be divided into stacked and wound types. Among them, wound cells often have excessively large gaps between the electrodes. During charging and discharging, excessively large gaps can easily lead to lithium deposition on the electrodes, causing thermal runaway and other safety accidents in wound cells. Utility Model Content
[0004] This application provides a battery cell and a battery pack to reduce the occurrence of safety accidents such as thermal runaway caused by lithium plating.
[0005] This application provides a battery cell, the battery cell comprising:
[0006] An electrode assembly has a first direction and a winding direction. The electrode assembly includes a first electrode, a second electrode, a first insulating layer, and a second insulating layer. The first electrode, the first insulating layer, the second electrode, and the second insulating layer are sequentially stacked and wound along the winding direction to form the electrode assembly. The electrode assembly has a first bending region and a second bending region opposite to each other along the first direction. In the first bending region, the second insulating layer is the innermost layer.
[0007] Multiple first barrier layers are disposed between the first electrode sheet and the first isolation layer of the first loop wound from the inside to the outside in the first bending area. Along the winding direction, two adjacent first barrier layers are spaced apart to form a first gap.
[0008] In some possible implementations, a plurality of first barrier layers are disposed between the first electrode sheet and the first isolation layer of the first turn of the second bending region wound from the inside out, and adjacent first barrier layers are spaced apart along the winding direction to form a first gap.
[0009] In some possible implementations, the first electrode includes a first current collector and a first active material layer coated on the side of the first current collector facing the second electrode, and the first barrier layer is disposed on the side of the first active material layer away from the first current collector.
[0010] In some possible implementations, the first electrode includes a first starting segment, the second electrode includes a second starting segment, the second insulating layer is located inside the second starting segment, the second starting segment is located inside the first starting segment, and the extension length of the second starting segment along the first direction exceeds the extension length of the first starting segment along the first direction.
[0011] In some possible implementations, the electrode assembly also has a second direction intersecting the first direction;
[0012] The first length of the first barrier layer along the second direction is greater than or equal to the second length of the first electrode along the second direction.
[0013] In some possible implementations, the battery cell further includes a plurality of second barrier layers disposed on the side of the first electrode away from the first barrier layer;
[0014] Multiple second barrier layers are disposed between the first electrode sheet in the first loop and the second isolation layer in the second loop of the first bending area wound from the inside out. Along the winding direction, two adjacent second barrier layers are spaced apart to form a second gap.
[0015] In some possible implementations, there are two first barrier layers disposed on the first electrode, the two first barrier layers are spaced apart and form the first gap, the electrode assembly has a central axis parallel to the first direction, and the two first barrier layers are symmetrically arranged about the central axis.
[0016] In some possible implementations, the first barrier layer is an adhesive layer, and the porosity of the first barrier layer is less than that of the first isolation layer and the second isolation layer.
[0017] In some possible implementations, the first electrode is a positive electrode and the second electrode is a negative electrode.
[0018] In addition, this application also provides a battery pack, including the battery cells described in the above embodiments.
[0019] The beneficial effects of this application are as follows: In the battery cell provided by this application, multiple first barrier layers are provided between the first electrode sheet and the first insulating layer of the first winding from the inside to the outside in the first bending region, which can insulate the corresponding position of the first electrode sheet. Therefore, during charging, the first barrier layers can prevent lithium ions from being released from the corresponding position of the first electrode sheet, thus reducing the amount of lithium ions released from the first electrode sheet and lowering the possibility of lithium plating on the surface of the second electrode sheet. This further reduces the loss of lithium ions in the battery cell, extends the battery cell's lifespan, and also reduces the possibility of the first insulating layer being punctured by lithium dendrites, lowering the possibility of thermal runaway and other safety accidents in the battery cell. In addition, multiple first barrier layers are provided in the first winding of the first bending region, and there is a first gap between adjacent first barrier layers along the winding direction. Therefore, the multiple first barrier layers can provide support for the first electrode sheet, preventing the bending angle of the first electrode sheet in the first bending region from being too large. This further reduces the possibility of excessive local stress caused by excessive bending angle in the first bending region, lowering the risk of breakage of the first electrode sheet due to excessive local stress. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 Schematic diagrams of the battery cells in some embodiments are shown;
[0022] Figure 2 A partial cross-sectional view of the first electrode and the first barrier layer in some embodiments is shown;
[0023] Figure 3 A schematic diagram of the structure of the first electrode sheet when it is unfolded is shown in some embodiments;
[0024] Figure 4 A cross-sectional structural schematic diagram of the second electrode sheet is shown in some embodiments;
[0025] Figure 5 A schematic diagram of the structure of the first bending region is shown in some embodiments;
[0026] Figure 6 A schematic diagram of the structure of the second bending region is shown in some embodiments.
[0027] Explanation of key component symbols:
[0028] 100-cell battery;
[0029] 110 - Electrode assembly; 111 - First electrode; 11101 - First starting segment; 11102 - First tail segment; 11103 - First bend; 11104 - Second bend; 1111 - First current collector; 1112 - First active material layer; 112 - Second electrode; 11201 - Second starting segment; 11202 - Second tail segment; 11203 - Third bend; 11204 - Fourth bend; 1121 - Second current collector; 1122 - Second active material layer; 1131 - First insulating layer; 1132 - Second insulating layer;
[0030] 120 - First barrier layer; 1201 - Base film; 1202 - Adhesive layer; 121 - First gap;
[0031] 130 - Second barrier layer; 131 - Second gap;
[0032] 210 - First bend zone; 220 - Second bend zone; 230 - Straight zone;
[0033] X - First direction; Y - Second direction; L - Central axis; A - Winding direction. Detailed Implementation
[0034] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0035] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to 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 according to the specific circumstances.
[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0039] like Figures 1 to 3 As shown, the embodiment provides a battery cell 100, including an electrode assembly 110 and a plurality of first barrier layers 120.
[0040] The electrode assembly 110 has a first direction X and a winding direction A. The electrode assembly 110 also includes a first electrode 111, a second electrode 112, a first insulating layer 1131, and a second insulating layer 1132. The first electrode 111, the first insulating layer 1131, the second electrode 112, and the second insulating layer 1132 are sequentially stacked and wound along the winding direction A to form the electrode assembly 110. Additionally, the electrode assembly 110 includes a first bending region 210 and a second bending region 220, which are respectively disposed at both ends of the electrode assembly 110 along the first direction X.
[0041] In some embodiments, the first electrode 111 and the second electrode 112 have opposite polarities. The first electrode 111 can be a positive electrode, and the second electrode 112 can be a negative electrode.
[0042] In this embodiment, a plurality of first barrier layers 120 may be disposed between the first electrode sheet 111 and the first insulating layer 1131 of the first bend region 210 wound from the inside out. In some embodiments, the plurality of first barrier layers 120 may be arranged sequentially along the winding direction A of the electrode assembly 110. Along the winding direction A, two adjacent first barrier layers 120 are spaced apart and form a first gap 121.
[0043] During the processing of electrode assembly 110, the wound electrode assembly 110 needs to undergo a hot pressing process. During hot pressing, the first electrode 111 and the second electrode 112 in the first bending region 210 of electrode assembly 110 may become misaligned, especially the first loop of first electrode 111 and second electrode 112 wound from the inside out in the first bending region 210. This results in an excessively large gap between the first electrode 111 and the second electrode 112. During charging, the amount of lithium ions released from the first electrode 111 may exceed the amount of lithium ions that the second electrode 112 can accept. The free lithium ions will combine with electrons to form metallic lithium and deposit on the surface of the second electrode 112, forming lithium plating. Lithium plating causes irreversible loss of lithium ions in the battery cell 100, affecting the lifespan of the battery cell 100. Furthermore, lithium dendrites deposited on the surface of the second electrode 112 may pierce the first insulating layer 1131, causing a short circuit in the battery cell 100 and potentially leading to thermal runaway and other safety accidents.
[0044] In this embodiment, a first barrier layer 120 is provided between the first electrode 111 wound from the inside out in the first bending region 210 and the first insulating layer 1131, which can insulate the position of the first barrier layer 120 in the first electrode 111. Therefore, during charging, the first barrier layer 120 can prevent lithium ions from being released from the corresponding position of the first electrode 111, thus reducing the amount of lithium ions released from the first electrode 111 and lowering the possibility of lithium plating on the surface of the second electrode 112. Furthermore, this reduces the loss of lithium ions in the battery cell 100, extends the service life of the battery cell 100, and also reduces the possibility of the first insulating layer 1131 being punctured by lithium dendrites, lowering the possibility of thermal runaway and other safety accidents in the battery cell 100.
[0045] In addition, in this embodiment of the application, a plurality of first barrier layers 120 are provided between the first electrode 111 wound from the inside to the outside in the first bending area 210 and the first isolation layer 1131. Along the winding direction A, there is a first gap 121 between two adjacent first barrier layers 120. The plurality of first barrier layers 120 can provide support for the first electrode 111, so as to avoid the bending angle of the first electrode 111 in the first bending area 210 being too large. In this way, the possibility of the first electrode 111 generating excessive local stress in the first bending area 210 due to excessive bending angle can be reduced, and the risk of the first electrode 111 breaking due to excessive local stress can be reduced.
[0046] like Figure 1As shown, the electrode assembly 110 also includes a flat region 230. It is understood that, correspondingly, the portions of the first electrode 111, the second electrode 112, the first insulating layer 1131, and the second insulating layer 1132 located in the first bending region 210 and the second bending region 220 can all be arc-shaped. The flat region 230 can be located between the first bending region 210 and the second bending region 220 along the first direction X.
[0047] like Figure 1 As shown, in some embodiments, the first electrode 111 includes a first starting segment 11101, which may be located in the flat region 230. One end of the first starting segment 11101 facing the second bending region 220 may be the winding starting end of the first electrode 111.
[0048] The second electrode 112 includes a second starting segment 11201, which may also be located in the straight region 230. The end of the second starting segment 11201 facing the second bending region 220 may be the winding starting end of the second electrode 112.
[0049] In some embodiments, the extension length of the second starting segment 11201 along the first direction X exceeds the extension length of the first starting segment 11101 along the first direction X. Correspondingly, the end of the second starting segment 11201 facing the second bending region 220 may protrude relative to the end of the first starting segment 11101 facing the second bending region 220. This ensures that the first starting segment 11101 of the first electrode 111 is completely covered by the second starting segment 11201 of the second electrode 112, so that lithium ions released from the first starting segment 11101 during charging are received by the second starting segment 11201 as much as possible, reducing the probability of lithium plating problems.
[0050] In some embodiments, the first bend (i.e., the first bend 11103) formed by winding the first electrode 111 starting from the first starting segment 11101 may be located in the first bend area of the first bend region 210 winding from the inside out. The second bend (i.e., the second bend 11104) formed by winding the first electrode 111 starting from the first starting segment 11101 may be located in the second bend region 220, and may be located in the first bend area of the second bend region 220 winding from the inside out. In embodiments, the bends formed by winding the first electrode 111 may be alternately arranged in the first bend region 210 and the second bend region 220.
[0051] In some embodiments, the first electrode 111 may include at least one bend in the first bending region 210, for example, one, two, three, or any other number of bends. The first electrode 111 may include zero, one, two, or any other number of bends in the second bending region 220.
[0052] The first bend (i.e., the third bend 11203) formed by winding the second electrode 112 starting from the second starting segment 11201 can be located in the first bend area of the first bend area wound from the inside out in the first bend area 210. The second bend (i.e., the fourth bend 11204) formed by winding the second electrode 112 starting from the second starting segment 11201 can be located in the first bend area of the second bend area wound from the inside out in the second bend area 220. In the embodiment, the bends formed by winding the second electrode 112 can also be alternately arranged in the first bend area 210 and the second bend area 220.
[0053] In some embodiments, the second electrode 112 may include at least two bends in the first bending region 210, for example, two, three, four, or any other number of bends. The second electrode 112 may include at least one bend in the second bending region 220, for example, one, two, or any other number of bends.
[0054] like Figure 1 and Figure 6 As shown, in some embodiments, the first electrode 111 further includes a first tail segment 11102. The first tail segment 11102 may be located in the second bending region 220. The movable end of the first tail segment 11102 may be the end of the first electrode 111 being wound. The second electrode 112 may include a second tail segment 11202, which may be located in the straight region 230. The movable end of the second tail segment 11202 may be the end of the second electrode 112 being wound. In some embodiments, the winding length of the second electrode 112 may be greater than the winding length of the first electrode 111 to cover at least a portion of the first electrode 111 in the outer layer.
[0055] like Figures 2 to 5 As shown, in some embodiments, the first electrode 111 may include a first current collector 1111 and a first active material layer 1112 coated on the side of the first current collector 1111 facing the second electrode 112. The first current collector 1111 may be made of aluminum. The first active material layer 1112 may be a positive electrode active material, including but not limited to lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The first active material layer 1112 allows for the extraction and insertion of lithium ions.
[0056] Of course, in some embodiments, the side of the first current collector 1111 away from the second electrode 112 may also be coated with a first active material layer 1112.
[0057] The second electrode 112 may include a second current collector 1121 and a second active material layer 1122 coated on the side of the second current collector 1121 facing the first electrode 111. In some embodiments, the side of the second current collector 1121 away from the first electrode 111 may also be coated with the second active material layer 1122. In embodiments, the second current collector 1121 may be made of copper. The second active material layer 1122 may be a negative electrode active material, including but not limited to materials such as carbon and silicon. The second active material layer 1122 allows for the extraction and insertion of lithium ions.
[0058] like Figure 1 As shown, in some embodiments, both the first isolation layer 1131 and the second isolation layer 1132 can be made of materials such as polypropylene (PP) and polyethylene (PE).
[0059] In some embodiments, the starting segment of the second insulating layer 1132 may be located inside the second electrode 112. That is, the starting end of the second insulating layer 1132 may be located on the side of the second starting segment 11201 away from the first starting segment 11101. Additionally, the tail segment of the second insulating layer 1132 may be disposed outside the first tail segment 11102 in the first electrode 111. In another embodiment, the tail segment of the first insulating layer 1131 may be disposed outside the second tail segment 11202 in the second electrode 112.
[0060] like Figures 1 to 3 as well as Figure 5 As shown, in some embodiments, the first bend 11103 is the first bend formed by winding the first electrode 111 starting from the first starting segment 11101. Compared to other bends in the first electrode 111, the first bend 11103 may have a relatively small winding diameter. During the hot pressing process, there is a higher possibility that an excessively large gap will appear between the first bend 11103 and the third bend 11203 of the second electrode 112. In the embodiments, a plurality of first barrier layers 120 may be provided on the side of the first bend 11103 facing the second electrode 112.
[0061] In some embodiments, the first barrier layer 120 may be an adhesive layer, which can be adhered to the side of the first active material layer 1112 away from the first current collector 1111. Accordingly, the first barrier layer 120 may include a base film 1201 and an adhesive layer 1202 coated on the side of the base film 1201 facing the first active material layer 1112. The adhesive layer 1202 can be bonded between the base film 1201 and the first active material layer 1112, so that the first barrier layer 120 is fixedly disposed relative to the first electrode 111, preventing the first barrier layer 120 from detaching from the first electrode 111 at will. In some embodiments, the base film 1201 may be made of materials such as polyimide (PI), polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (PE). The adhesive layer 1202 can be made of materials such as polyvinylidene difluoride (PVDF) and polytetrafluoroethylene (PTFE).
[0062] Furthermore, the porosity of the first barrier layer 120 is less than that of the first isolation layer 1131 and the second isolation layer 1132. Therefore, the first barrier layer 120 can effectively prevent the extraction of lithium ions from the corresponding position of the first electrode 111.
[0063] In some embodiments, the thickness d of the first barrier layer 120 can be set to 5μm to 100μm, which can prevent lithium ions from being extracted from the corresponding position of the first electrode 111 while avoiding the occupation of a large space and the resulting increase in the gap between the first electrode 111 and the second electrode 112. Exemplarily, in some embodiments, the thickness d of the first barrier layer 120 can be set to any value from 5μm to 100μm, including 5μm, 16μm, 21μm, 25μm, 34μm, 42μm, 48μm, 52μm, 55μm, 60μm, 65μm, 72μm, 78μm, 81μm, 88μm, 95μm, 100μm, or any other value from 5μm to 100μm.
[0064] In some embodiments, the electrode assembly 110 further has a central axis L parallel to the first direction X. Two first blocking layers 120 are provided on the side of the first bend 11103 facing the first coil of the second electrode 112 wound from the inside out. A first gap 121 is provided between the two first blocking layers 120, thereby providing support for the first electrode 111 and preventing the bending angle of the first electrode 111 in the first bend area 210 from being too large. This reduces the possibility of excessive local stress in the first electrode 111 in the first bend area 210 due to excessive bending angle, reducing the risk of breakage of the first electrode 111 due to excessive local stress. Simultaneously, it releases stress at the corresponding position of the first electrode 111, and the two first blocking layers 120 are symmetrically arranged about the central axis L.
[0065] In some embodiments, the width n of the first gap 121 can be set to 0.01 mm to 2.00 mm, which can effectively release the stress at the corresponding position of the first electrode 111 and reduce the risk of the first bent portion 11103 of the first electrode 111 breaking due to excessive local stress. Exemplarily, in some embodiments, the width n of the first gap 121 can be set to any other value from 0.01 mm to 2.00 mm, including 0.01 mm, 0.15 mm, 0.28 mm, 0.35 mm, 0.41 mm, 0.50 mm, 0.56 mm, 0.75 mm, 1.00 mm, 1.21 mm, 1.35 mm, 1.44 mm, 1.65 mm, 1.8 mm, 1.95 mm, 1.00 mm, or 0.01 mm to 2.00 mm.
[0066] In some embodiments, the first barrier layer 120 may have a width m along the winding direction A. The width m of the first barrier layer 120 may be set to 5 mm to 30 mm, which prevents lithium ions from being extracted from the corresponding position of the first electrode 111 and thus avoids lithium plating, while also preventing additional loss of lithium ions. Exemplarily, in some embodiments, the width m of the first barrier layer 120 may be set to 5 mm, 5.6 mm, 6 mm, 7.5 mm, 9 mm, 12.5 mm, 13 mm, 15.2 mm, 16.5 mm, 18 mm, 19.4 mm, 20.5 mm, 22.2 mm, 23 mm, 25.4 mm, 27.5 mm, 28 mm, 30 mm, or any other value from 5 mm to 30 mm.
[0067] In some embodiments, the electrode assembly 110 further has a second direction Y intersecting the first direction X. The first length L1 of the first barrier layer 120 along the second direction Y may be greater than or equal to the second length L2 of the first electrode 111 along the second direction Y. This reduces the probability of lithium plating problems occurring at various positions of the second electrode 112 in the second direction Y.
[0068] In some embodiments, three, four, or other numbers of first blocking layers 120 may be provided on the side of the first bend 11103 facing the first turn of the second electrode 112 wound from the inside out. The plurality of first blocking layers 120 may be arranged sequentially at intervals along the winding direction A. A first gap 121 is provided between any two adjacent first blocking layers 120. Furthermore, the plurality of first blocking layers 120 may be arranged symmetrically or asymmetrically about the central axis L.
[0069] like Figure 1 , Figure 2 and Figure 5 As shown, in some embodiments, both sides of the first electrode 111 are coated with a first active material layer 1112, and both sides of the second electrode 112 are coated with a second active material layer 1122. A large gap may also occur between the side of the first bent portion 11103 away from the first barrier layer 120 and the second loop of the second electrode 112 wound from the inside out of the first bent region 210, leading to lithium plating problems. In this embodiment, multiple second barrier layers 130 are provided between the first loop of the first electrode 111 wound from the inside out of the first bent region 210 and the second loop of the second isolation layer 1132. That is, multiple second barrier layers 130 can be provided on the side of the first bent portion 11103 away from the first barrier layer 120. Along the winding direction A, adjacent second barrier layers 130 are spaced apart, forming a second gap 131.
[0070] In this embodiment, the structure of the second barrier layer 130 may be similar to that of the first barrier layer 120. It is understood that the side of the first bend 11103 away from the first barrier layer 120 may have a relatively larger winding diameter compared to the side of the first bend 11103 facing the first barrier layer 120, thus reducing stress concentration on that side. Accordingly, in some embodiments, a second barrier layer 130 may also be provided on the side of the first bend 11103 away from the first barrier layer 120.
[0071] In some embodiments, three, four, or any other number of second barrier layers 130 may also be provided on the side of the first bend 11103 away from the first barrier layer 120.
[0072] It is understandable that the side of the second bend 11104 facing the first loop of the second electrode 112 wound from the inside out in the second bend region 220 has a relatively larger winding diameter than the side of the first bend 11103 facing the first loop of the second electrode 112 wound from the inside out in the first bend region 210. However, the second bend 11104 is still in the inner winding layer of the electrode assembly 110, and there may be an excessively large gap between the second bend 11104 and the second electrode 112, which could lead to lithium plating problems. In the embodiment, multiple first barrier layers 120 can also be provided on the side of the second bend 11104 facing the fourth bend 11204 in the second electrode 112, which can reduce the probability of lithium plating problems occurring at the location of the second bend 11104.
[0073] In some embodiments, in the first bending region 210 and the second bending region 220, in the winding layer where lithium plating problems may occur, a first barrier layer 120 can be provided on the side of the first electrode 111 facing the second electrode 112 to prevent excessive lithium ions from being extracted from the first electrode 111 at the corresponding position.
[0074] It is understood that the electrode assembly 110 may further include a first tab connected to the first electrode 111 and a second tab connected to the second electrode 112. The battery cell 100 may further include structures such as a housing and a top cover assembly. The housing and the top cover assembly can be fitted together to form an assembly cavity, in which the electrode assembly 110 can be disposed, the first tab can be connected to the positive terminal on the top cover assembly, and the second tab can be connected to the negative terminal on the top cover assembly.
[0075] The embodiment also provides a battery pack, which may include the battery cell 100 provided in the embodiment.
[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0077] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A battery cell, characterized in that, The battery cell includes: An electrode assembly (110) has a first direction (X) and a winding direction (A). The electrode assembly (110) includes a first electrode (111), a second electrode (112), a first insulating layer (1131), and a second insulating layer (1132). The first electrode (111), the first insulating layer (1131), the second electrode (112), and the second insulating layer (1132) are sequentially stacked and wound along the winding direction (A) to form the electrode assembly (110). The electrode assembly (110) has a first bending region (210) and a second bending region (220) opposite to each other along the first direction (X). In the first bending region (210), the second insulating layer (1132) is the innermost layer. Multiple first barrier layers (120) are disposed between the first electrode sheet (111) and the first isolation layer (1131) of the first bend area (210) wound from the inside to the outside. Along the winding direction (A), two adjacent first barrier layers (120) are spaced apart and form a first gap (121).
2. The battery cell according to claim 1, characterized in that, Multiple first barrier layers (120) are disposed between the first electrode sheet (111) and the first isolation layer (1131) of the first loop wound from the inside to the outside in the second bending area (220). Along the winding direction (A), two adjacent first barrier layers (120) are spaced apart and form a first gap (121).
3. The battery cell according to claim 1 or 2, characterized in that, The first electrode (111) includes a first current collector (1111) and a first active material layer (1112) coated on the side of the first current collector (1111) facing the second electrode (112), and the first barrier layer (120) is disposed on the side of the first active material layer (1112) away from the first current collector (1111).
4. The battery cell according to claim 1, characterized in that, The first electrode (111) includes a first starting segment (11101), the second electrode (112) includes a second starting segment (11201), the second insulating layer (1132) is located inside the second starting segment (11201), the second starting segment (11201) is located inside the first starting segment (11101), and the extension length of the second starting segment (11201) along the first direction (X) exceeds the extension length of the first starting segment (11101) along the first direction (X).
5. The battery cell according to claim 1, characterized in that, The electrode assembly (110) also has a second direction (Y) intersecting the first direction (X); The first length of the first barrier layer (120) along the second direction (Y) is greater than or equal to the second length of the first electrode (111) along the second direction (Y).
6. The battery cell according to claim 1, characterized in that, The battery cell also includes a plurality of second barrier layers (130), which are disposed on the side of the first electrode (111) away from the first barrier layer (120); Multiple second barrier layers (130) are disposed between the first electrode sheet (111) and the second isolation layer (1132) of the first bending area (210) wound from the inside to the outside. Along the winding direction (A), two adjacent second barrier layers (130) are spaced apart and form a second gap (131).
7. The battery cell according to claim 1, characterized in that, There are two first barrier layers (120), and the two first barrier layers (120) are disposed on the first electrode (111). The two first barrier layers (120) are spaced apart and form the first gap (121). The electrode assembly (110) has a central axis (L), which is parallel to the first direction (X). The two first barrier layers (120) are symmetrically arranged about the central axis (L).
8. The battery cell according to claim 1, characterized in that, The first barrier layer (120) is an adhesive layer, and the porosity of the first barrier layer (120) is less than that of the first isolation layer (1131) and the second isolation layer (1132).
9. The battery cell according to claim 1, characterized in that, The first electrode (111) is a positive electrode, and the second electrode (112) is a negative electrode.
10. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1 to 9.