Battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and provides a battery cell and a battery, and the battery cell comprises a positive plate, a diaphragm and a negative plate which are wound and stacked; the negative plate comprises a negative current collector and a negative active material layer located on the negative current collector, and a plurality of negative tabs protrude out of one side of the negative current collector and are laminated to form a negative tab structure; the positive plate comprises a positive current collector and positive active material layers, and the positive active material layers are arranged on two opposite sides of the positive current collector; the positive active material layer is provided with a first empty foil area and a second empty foil area, a first tab of the positive plate is positioned in the first empty foil area and connected with the positive current collector, and a second tab is positioned in the second empty foil area and connected with the positive current collector; and the first tab and the second tab are positioned on the two sides of the negative tab structure along the second direction. Through the arrangement, the bending space ratio of the first tab, the second tab and the negative tab at the top of the battery cell is reduced, the space ratio of the battery cell is reduced, and the energy density of the battery cell is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell and a battery. Background Technology

[0002] With people's growing needs, batteries are gradually developing towards fast charging, long lifespan, high energy density, and high safety.

[0003] In related technologies, a battery cell includes a positive electrode and a negative electrode. Both the positive and negative electrode have multiple tabs. After the positive and negative electrode are wound together, the multiple tabs on the positive electrode form a positive tab group, and the multiple tabs on the negative electrode form a negative tab group. The positive tab group and the negative tab group are stacked along the thickness direction of the battery cell. After the battery cell is packaged, the positive and negative tab groups need to be soldered to additional rigid tabs. Furthermore, to prevent the battery cell from becoming too wide, the rigid tabs need to be bent multiple times.

[0004] However, such cells occupy a large space, making it difficult to improve the energy density of the battery. Utility Model Content

[0005] This application provides a battery cell and battery that can reduce space occupation and increase energy density.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides a battery cell, comprising:

[0008] Positive electrode, separator and negative electrode are wound and stacked.

[0009] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector. The negative electrode sheet also includes a plurality of negative electrode tabs extending from one side of the negative electrode current collector, and the plurality of negative electrode tabs are stacked along a first direction to form a negative electrode tab structure.

[0010] The positive electrode sheet includes a positive current collector and a positive active material layer, the positive active material layer being disposed on opposite sides of the positive current collector in the thickness direction; the positive active material layer having a first empty foil region and a second empty foil region, the first empty foil region and the second empty foil region being spaced apart along the first direction; the positive electrode sheet includes a first tab and a second tab, the first tab being located in the first empty foil region and connected to the positive current collector, the second tab being located in the second empty foil region and connected to the positive current collector; and the first tab and the second tab being located on opposite sides of the negative tab structure along the second direction.

[0011] The first direction and the second direction intersect.

[0012] As an optional implementation, the positive electrode has a winding head located on the inner ring of the cell and a winding tail located on the outer ring of the cell.

[0013] The second empty foil area is located at the winding head or the winding tail.

[0014] As an optional implementation, there are two first empty foil regions, which are disposed on opposite sides of the positive current collector along the thickness direction of the positive current collector; the first electrode tab is located in one of the two first empty foil regions.

[0015] Alternatively, along the thickness direction of the positive current collector, the orthographic projection of the first empty foil area onto the surface where the positive current collector is located overlaps with the orthographic projection of the positive active material layer on the side surface of the positive current collector away from the first empty foil area onto the surface where the positive current collector is located.

[0016] As an optional implementation, the positive electrode active material layer has a first groove, the first groove and the first electrode tab are correspondingly disposed, the first empty foil area is exposed from the first groove, and the first electrode tab is located in the first groove.

[0017] And / or, the positive electrode active material layer has a second groove, the second groove and the second tab are positioned correspondingly, the second empty foil area is exposed from the second groove, and the second tab is located in the second groove.

[0018] As an optional implementation, the positive electrode sheet has a first notch, and along the width direction of the positive current collector, the first notch and the first groove are disposed opposite to each other on both sides of the positive electrode sheet.

[0019] And / or, the positive electrode sheet has a second notch, and along the width direction of the positive current collector, the second notch and the second groove are disposed opposite to each other on both sides of the positive electrode sheet.

[0020] As an optional implementation, the battery cell further includes a first protective element, which is provided in a one-to-one correspondence with the first empty foil area, and at least part of the first protective element covers the first empty foil area.

[0021] And / or, the battery cell includes a second protective element, the second protective element and the second empty foil area are respectively arranged in a one-to-one correspondence, and at least part of the first protective element covers the second empty foil area.

[0022] As an optional implementation, the battery cell further includes at least one of the following:

[0023] The battery cell also includes a plurality of third protective components, which are respectively disposed on the side of the negative electrode sheet facing the first tab and the second tab.

[0024] The cell also includes a fourth protective element, which is disposed on the negative electrode plate located in the inner ring of the cell along the second direction and facing at least one side of the separator.

[0025] The battery cell also includes a fifth protective component, which is disposed on the negative electrode sheet located on the inner ring of the battery cell and facing the diaphragm along the thickness direction of the positive current collector.

[0026] The battery cell also includes a sixth protective component, which is disposed on the outer ring of the battery cell and at least partially covers the winding tail of the positive electrode sheet.

[0027] As an optional implementation, on the positive electrode plate located on the outer ring of the battery cell, the orthogonal projection of at least one of the first tab, the second tab, and the negative tab structures overlaps with the orthogonal projection of the sixth protective element.

[0028] As an optional implementation, along the width direction of the positive current collector, the edge of the negative current collector has a gap with the edge on the same side of at least one of the third protective member, the fourth protective member, and the fifth protective member; the gap is 0.1mm-5mm.

[0029] As an optional implementation, the negative electrode active material layer extends to the negative electrode tab along the width direction of the negative electrode current collector.

[0030] On the negative electrode tab, the edge of the negative electrode active material layer is located between the edge of the negative electrode current collector and the edge on the same side of at least one of the third protective member, the fourth protective member, and the fifth protective member.

[0031] As an optional implementation, the battery cell has a bending region.

[0032] The fourth protective element is located in the portion of the negative electrode sheet in the bending area; along the second direction, the fourth protective element is offset from the first electrode tab and the second electrode tab; along the third direction, the projections of the fourth protective element, the first electrode tab, and the second electrode tab on the same plane do not overlap.

[0033] The second direction and the third direction are perpendicular to each other.

[0034] As an optional implementation, the negative electrode includes a single-sided area and an empty foil area located at the beginning of the winding, and the fifth protective member is located in the empty foil area at the beginning of the winding.

[0035] The projection of the fifth protective component in the thickness direction of the battery cell overlaps with the winding head of the positive electrode sheet.

[0036] The projection of the fifth protective element in the thickness direction of the battery cell and the orthogonal projection of the negative electrode tab on the surface where the fifth protective element is located at least partially overlap.

[0037] As an optional implementation, the diaphragm has a fold-back section located in the inner ring of the cell and along a second direction, the fold-back section and the negative electrode tab structure located in the inner ring of the cell having an overlapping portion.

[0038] Secondly, this application provides a battery including the cell described in the first aspect.

[0039] This application provides a battery cell and a battery, wherein the battery cell includes: a positive electrode sheet, a separator, and a negative electrode sheet wound and stacked; the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector, and the negative electrode sheet also includes a plurality of negative electrode tabs extending from one side of the negative electrode current collector, the plurality of negative electrode tabs being stacked along a first direction to form a negative electrode tab structure; the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer being disposed on opposite sides of the positive electrode current collector in the thickness direction; the positive electrode active material layer has a first empty foil region and a second empty foil region, the first empty foil region and the second empty foil region being spaced apart along the first direction; the positive electrode sheet includes a first electrode tab and a second electrode tab, the first electrode tab being located in the first empty foil region and connected to the positive electrode current collector, the second electrode tab being located in the second empty foil region and connected to the positive electrode current collector; and the first electrode tab and the second electrode tab being located on opposite sides of the negative electrode tab structure along a second direction. By setting the first and second tabs, the bending space ratio of the first, second, and negative tab structures at the top of the cell is reduced. This further narrows the distance between the cell and the top space of the package, increasing the cell's energy density and improving the space utilization of the package. The positive electrode uses the first and second empty foil areas to weld the first and second tabs, effectively avoiding the localized overheating that often occurs in multi-tab cells. This slows down the temperature rise during charging and discharging, ensuring the cell's charge / discharge performance and cycle performance. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of a battery cell provided in an embodiment of this application;

[0042] Figure 2 for Figure 1 Sectional view along axis AA;

[0043] Figure 3 A schematic diagram of the positive electrode plate in the battery cell provided in the embodiments of this application. Figure 1 ;

[0044] Figure 4 A schematic diagram of the positive electrode plate in the battery cell provided in the embodiments of this application. Figure 2 ;

[0045] Figure 5 A partial structural diagram of the positive and negative electrode plates in the battery cell provided in the embodiments of this application. Figure 1 ;

[0046] Figure 6 A partial structural diagram of the positive and negative electrode plates in the battery cell provided in the embodiments of this application. Figure 2 ;

[0047] Figure 7 This is a schematic diagram of the negative electrode plate in the battery cell provided in an embodiment of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 100-cell;

[0050] 110 - Positive electrode plate; 111 - First tab; 112 - Second tab; 113 - Positive current collector;

[0051] 114 - Positive electrode active material layer; 1141 - First empty foil region; 1142 - Second empty foil region;

[0052] 115 - Head winding; 116 - Tail winding; 117 - First notch; 118 - Second notch;

[0053] 120 - Negative electrode sheet; 121 - Negative electrode tab; 122 - Negative electrode tab structure;

[0054] 130-diaphragm; 131-return section;

[0055] 140 - First protective component; 141 - Second protective component; 142 - Third protective component; 143 - Fourth protective component; 144 - Fifth protective component; 145 - Sixth protective component. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0057] In this application, the first direction is defined as the winding direction of the battery cell 100, the second direction is defined as the P direction, and the third direction is defined as the Q direction.

[0058] See Figure 1 and Figure 2 This application provides a battery cell 100, which includes a positive electrode 110, a separator 130 and a negative electrode 120 wound and stacked.

[0059] In some embodiments, the negative electrode sheet 120 includes a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material may be disposed on opposite sides of the negative electrode current collector in the thickness direction. The negative electrode sheet 120 also includes a plurality of negative electrode tabs 121, which extend from one side of the negative electrode current collector. After the negative electrode sheet 120 is wound, the plurality of negative electrode tabs 121 are stacked sequentially along the winding direction of the battery cell 100 to form a negative electrode tab structure 122, which are connected and electrically connected to each other through negative electrode tab adapters.

[0060] In some embodiments, the positive electrode sheet 110 also includes a positive current collector 113 and a positive active material layer 114. The positive active material layer 114 is disposed on opposite sides of the positive current collector 113 in the thickness direction, with multiple positive tabs extending out from one side of the positive current collector 113. After the positive electrode sheet 110 is wound, the multiple positive tabs are stacked sequentially along the winding direction of the cell 100 to form a positive tab structure. The positive tab structures are connected and electrically connected to each other through positive tab adapters.

[0061] Thus, the positive tab structure and the negative tab structure 122 are arranged along the second direction. During the battery cell 100 packaging process, the positive tab structure and the negative tab structure 122 need to be bent first, which can reduce the space ratio of the positive tab structure and the negative tab structure 122. Then the battery cell 100 is packaged. The positive tab adapter connected to the positive tab structure and the negative tab adapter connected to the negative tab structure 122 will extend to the outside of the packaging shell, so that the positive tab structure can be connected to the external device through the positive tab adapter, and the negative tab structure 122 can be electrically connected to the external device through the negative tab adapter.

[0062] The positive and negative tab structures 122 can reduce the space ratio of the cell 100 to some extent by bending. However, the bending space of the positive and negative tab structures 122 at the top of the cell 100 is limited. When there are many positive and negative tabs 121, the thickness of the corresponding positive tab structure and the thickness of the negative tab structure 122 increase, which further leads to a large bending space occupied by the positive and negative tab structures 122 at the top of the cell 100. It is difficult to reduce the space ratio of the cell 100, so it is difficult to improve the energy density of the cell 100. At the same time, since the bending of the positive and negative tab structures 122 occupies the top space of the packaging shell, the internal space utilization rate of the packaging shell is reduced.

[0063] To address the aforementioned issues, the positive electrode 110 in this embodiment includes a first tab 111 and a second tab 112, which are spaced apart along the length of the positive electrode 110. After the positive electrode 110, the separator 130, and the negative electrode 120 are stacked and wound, the first tab 111 and the second tab 112 are located on both sides of the negative electrode structure 122 along a second direction.

[0064] In this embodiment, the positive electrode 110 has only a first tab 111 and a second tab 112. This increases the width of the positive electrode 110, thereby reducing the space occupied by the bent positive tab structure on the positive electrode 110. This allows the distance between the battery cell 100 and the top space of the packaging shell to be reduced during packaging, further improving the energy density of the battery cell 100 and the space utilization of the packaging shell. Simultaneously, the first tab 111 and the second tab 112 are located on both sides of the negative tab structure 122, reducing the resistance inside the positive electrode 110 and the battery cell 100, thereby improving the power input and output capabilities of the battery cell 100. Furthermore, the spaced first tab 111 and second tab 112 prevent heat concentration in the battery cell 100, avoiding localized overheating and further enhancing the safety of the battery cell 100.

[0065] It should be noted that, see Figures 3-6 In this embodiment, the positive electrode active material layer 114 has a first empty foil region 1141 and a second empty foil region 1142, which are spaced apart along a first direction. A first tab 111 is located in the first empty foil region 1141 and connected to the positive electrode current collector 113, and a second tab 112 is located in the second empty foil region 1142 and connected to the positive electrode current collector 113.

[0066] For example, the first empty foil region 1141 and the second empty foil region 1142 can be a groove-shaped structure on the positive electrode active material layer 114. The groove-shaped structure penetrates the positive electrode active material layer 114 along the thickness direction of the positive electrode current collector 113, so that the positive electrode current collector 113 is exposed, so that the first electrode tab 111 is connected to the positive electrode current collector 113 in the first empty foil region 1141, and the second electrode tab 112 is connected to the positive electrode current collector 113 in the second empty foil region 1142.

[0067] In some embodiments, the edges of the first empty foil region 1141 and the same side of the positive current collector 113 are flush along the width direction of the positive current collector 113, or the first empty foil region 1141 and the same side edge of the positive current collector 113 are spaced apart. This application embodiment does not make specific requirements for this.

[0068] In some alternative implementations, the first empty foil region 1141 and the second empty foil region 1142 may be distributed on different sides of the positive electrode current collector 113 along the thickness direction of the positive electrode current collector 113. This application embodiment does not make specific requirements in this regard.

[0069] In some implementations, see Figure 2 Along the direction from the inner ring to the outer ring of the cell 100, the first empty foil region 1141 and the second empty foil region 1142 are both located on the positive electrode plate 110 and are close to the inner ring of the cell 100. Thus, in the cross-section of the cell 100, the first tab 111 and the second tab 112 are located on the positive electrode plate 110, and the first tab 111 and the second tab 112 are close to the center of the cell 100 along the second direction.

[0070] Alternatively, the first empty foil region 1141 and the second empty foil region 1142 are located on the positive electrode plate 110 and near the outer ring of the cell 100. In this way, on the cross-section of the cell 100, along the second direction, the first tab 111 and the second tab 112 are close to the outside of the cell 100, so that the heat generated by the first tab 111 and the second tab 112 during charging and discharging can be exchanged with the external environment of the cell 100, which helps to reduce the temperature of the cell 100 and improve the safety of the cell 100.

[0071] In some implementations, see Figure 4 The positive electrode 110 has a winding head 115 located in the inner ring of the cell 100 and a winding tail 116 located in the outer ring of the cell 100; the second empty foil area 1142 is located in the winding head 115 or the winding tail 116.

[0072] When the second empty foil area 1142 is located at the winding head 115, the second tab 112 is connected to the positive current collector 113, and the second tab 112 is located in the inner ring of the cell 100. When the second empty foil area 1142 is located at the winding tail 116, the second tab 112 is connected to the positive current collector 113, and the second tab 112 is located in the outer ring of the cell 100.

[0073] The first empty foil region 1141 and the second empty foil region 1142 are spaced apart on the positive electrode sheet 110 along the length direction of the positive electrode current collector 113. When the second empty foil region 1142 is located at the winding head 115, the first empty foil region 1141 may be located in the portion of the positive electrode current collector 113 near the winding head 115, or near the winding tail 116, along the length direction of the positive electrode current collector 113. When the second empty foil region 1142 is located at the winding tail 116, the first empty foil region 1141 may be located in the portion of the positive electrode current collector 113 near the winding tail 116, or near the winding head 115, along the length direction of the positive electrode current collector 113. This application embodiment does not impose specific requirements on this.

[0074] In some implementations, see Figure 5 The first empty foil region 1141 and the second empty foil region 1142 can each be one. The first electrode tab 111 is welded to the positive current collector 113 in the first empty foil region 1141, and the second electrode tab 112 is welded to the positive current collector 113 in the second empty foil region 1142.

[0075] In some implementations, see Figure 6 There are two first empty foil regions 1141, arranged opposite each other on both sides of the positive electrode current collector 113 along the thickness direction of the positive electrode current collector 113; the first tab 111 is located within one of the two first empty foil regions 1141. In this way, the two oppositely arranged first empty foil regions 1141 help to evenly distribute and dissipate heat in the battery cell 100, reducing the risk of localized overheating and thus improving the thermal stability and safety of the battery cell 100. In addition, the two first empty foil regions 1141 can improve the mechanical balance of the battery cell 100, reducing deformation or damage to the positive electrode sheet 110 due to asymmetrical stress during manufacturing and use.

[0076] In some embodiments, there are two second empty foil regions 1142. Along the thickness direction of the positive current collector 113, the two second empty foil regions 1142 are disposed opposite each other on both sides of the positive current collector 113, and the second tab 112 is located within one of the two second empty foil regions 1142. Thus, the two oppositely disposed second empty foil regions 1142 help to evenly distribute and dissipate heat in the battery cell 100, reducing the risk of localized overheating and thereby improving the thermal stability and safety of the battery cell 100. In addition, the two second empty foil regions 1142 can improve the mechanical balance of the battery cell 100, reducing deformation or damage to the positive electrode sheet 110 due to asymmetrical stress during manufacturing and use.

[0077] It should be noted that, in the embodiments of this application, the positive electrode active material layer 114 may have only two first empty foil regions 1141, or only two second empty foil regions 1142, or both the first empty foil region 1141 and the second empty foil region 1142 may have two. This application embodiment does not make specific requirements in this regard.

[0078] In some implementations, see Figure 5 Along the thickness direction of the positive electrode current collector 113, the orthographic projection of the first empty foil region 1141 onto the surface where the positive electrode current collector 113 is located overlaps with the orthographic projection of the positive electrode active material layer 114 on the side of the positive electrode current collector 113 opposite to the first empty foil region 1141 onto the surface where the positive electrode current collector 113 is located. That is to say, the first electrode tab 111 is welded to one side of the positive electrode current collector 113, and the other side of the positive electrode current collector 113 is covered with the positive electrode active material layer 114.

[0079] Understandably, the preparation process of the positive electrode 110 involves first processing a first empty foil region 1141 and a second empty foil region 1142 on a whole motherboard substrate, and then cutting the motherboard substrate into multiple positive electrode sheets 110 along the edges of the first empty foil region 1141 and the second empty foil region 1142. Due to issues such as slitting fluctuations or the precision of the slitting equipment, a positive active material layer 114 may exist between the edge of the positive electrode sheet 110 and the edges of the first empty foil region 1141 and the second empty foil region 1142 after slitting. This will affect the flatness of the positive electrode sheet 110 and make it difficult to connect the first tab 111 and the positive current collector 113 in the first empty foil region 1141, and the second tab 112 and the positive current collector 113 in the second empty foil region 1142. In related technologies, in order to solve this problem, it is necessary to perform a punching process on the positive active material layer 114 between the edge of the first empty foil region 1141 and the positive current collector 113, and the positive active material layer 114 between the edge of the second empty foil region 1142 and the positive current collector 113, so as to remove the positive active material layer 114 at this position. This will lead to a decrease in the difficulty and efficiency of the preparation of the positive electrode sheet 110.

[0080] Therefore, in this embodiment of the application, the positive electrode active material layer 114 has a first groove, the first groove and the first tab 111 are correspondingly arranged, the first empty foil area 1141 is exposed from the first groove, and the first tab 111 is located in the first groove.

[0081] It is easy to understand that by setting the first groove, the extension length of the first empty foil region 1141 in the width direction of the positive electrode current collector 113 is extended. In this way, the positive electrode 110 can be cut at the corresponding first groove on the mother plate electrode, avoiding the need for punching the positive electrode 110 after cutting. This reduces the number of punching operations on the positive electrode 110 during the manufacturing process, thereby avoiding the risk of increased punching burrs on the positive electrode 110 due to multiple punching operations, and improving the manufacturing efficiency of the positive electrode 110. The first tab 111 is located in the first groove to improve the flatness of the positive electrode 110.

[0082] In this embodiment, the positive electrode active material layer 114 has a second groove, and the second groove and the second tab 112 are positioned correspondingly. The second empty foil area 1142 is exposed from the second groove, and the second tab 112 is located within the second groove. By providing the second groove, this embodiment increases the extension length of the second empty foil area 1142 in the width direction of the positive electrode current collector 113. This allows for slitting at the corresponding second groove on the mother plate electrode, avoiding further punching of the positive electrode 110 after slitting, reducing the number of punching operations during the positive electrode 110's fabrication process, and thus avoiding the risk of increased punching burrs on the positive electrode 110 due to multiple punching operations. This also improves the fabrication efficiency of the positive electrode 110. The second tab 112 is located within the second groove to improve the flatness of the positive electrode 110.

[0083] In this embodiment, the positive electrode 110 has a first notch 117. Along the width direction of the positive current collector 113, the first notch 117 and the first groove are disposed opposite to each other on both sides of the positive electrode 110. It can be understood that the first empty foil area 1141 is located in the middle region of the positive current collector 113. The setting of the first notch 117 ensures that there is no exposed positive current collector 113 in the middle region of the positive electrode 110. Furthermore, it prevents the positive electrode 110 and the negative electrode 120 from short-circuiting at this position, thereby improving the insulation and safety of the cell 100.

[0084] In some embodiments, the positive electrode 110 has a second notch 118. Along the width direction of the positive current collector 113, the second notch 118 and the second groove are disposed opposite to each other on both sides of the positive electrode 110. In this embodiment, the second empty foil area 1142 is located in the middle region of the positive current collector 113. The provision of the second notch 118 ensures that there is no exposed positive current collector 113 in the middle region of the positive electrode 110, and further prevents the positive electrode 110 and the negative electrode 120 from short-circuiting at this position, thereby improving the insulation and safety of the cell 100.

[0085] It should be noted that the positive electrode 110 may have only the first notch 117 or the second notch 118, or may have both the first notch 117 and the second notch 118. This application embodiment does not require this.

[0086] Combination Figures 3-6 In some optional embodiments, the positive electrode 110 further includes a first protective element 140, which is configured in a one-to-one correspondence with the first empty foil area 1141, and at least part of the first protective element 140 covers the first empty foil area 1141.

[0087] In this embodiment, the first protective element 140 covers the first empty foil area 1141 to form an insulating barrier in the first empty foil area 1141, thereby improving the insulation of the positive electrode 110 and thus enhancing safety. Simultaneously, the first protective element 140 prevents welding burrs generated after welding the first tab 111 and the positive current collector 113 from piercing the separator 130, thus preventing the positive electrode 110 from contacting at the first empty foil area 1141 and causing an internal short circuit. This improves the insulation and safety of the positive electrode 110, further enhancing the insulation and safety of the battery cell 100.

[0088] It should be noted that when there is one first empty foil area 1141, there is one first protective member 140, and the first protective member 140 covers the first empty foil area 1141. When there are two first empty foil areas 1141, the two first empty foil areas 1141 are arranged opposite each other along the thickness direction of the positive electrode current collector 113, and there are two first protective members 140. The first protective members 140 correspond one-to-one with the first empty foil areas 1141 and cover the corresponding first empty foil areas 1141.

[0089] In some embodiments, the positive electrode 110 includes a second protective member 141, which is disposed in a one-to-one correspondence with the second empty foil area 1142, with at least a portion of the first protective member 140 covering the second empty foil area 1142. In this embodiment, the second protective member 141 covers the second empty foil area 1142 to form an insulating barrier in the second empty foil area 1142, thereby improving the insulation of the positive electrode 110 and thus enhancing safety. Simultaneously, the second protective member 141 prevents welding burrs generated after welding the second tab 112 and the positive current collector 113 from piercing the separator 130, thus preventing the positive electrode 110 from contacting at the second empty foil area 1142 and causing an internal short circuit, thereby improving the insulation and safety of the positive electrode 110 and further enhancing the insulation and safety of the battery cell 100.

[0090] It should be noted that when there is one second empty foil area 1142, there is one second protective element 141, and the second protective element 141 covers the second empty foil area 1142. When there are two second empty foil areas 1142, the two second empty foil areas 1142 are arranged opposite each other along the thickness direction of the positive electrode current collector 113, and there are two second protective elements 141. The second protective elements 141 correspond one-to-one with the second empty foil areas 1142 and cover the corresponding second empty foil areas 1142.

[0091] In some implementations, combined Figure 3 , Figure 5 and Figure 6 The negative electrode 120 also includes a plurality of third protective elements 142, which are respectively disposed on the side of the negative electrode 120 facing the first tab 111 and the second tab 112. Thus, the third protective elements 142 prevent short circuits caused by welding burrs of the first tab 111 and the positive current collector 113 piercing the separator 130 and the negative electrode 120, and also prevent short circuits caused by welding burrs of the second tab 112 and the positive current collector 113 piercing the separator 130 and the negative electrode 120, thereby improving the stability and safety of the electrical connections inside the cell 100.

[0092] In some implementations, see Figure 2 and Figure 7 The battery cell 100 also includes a fourth protective member 143, which is disposed on the negative electrode plate 120 located in the inner ring of the battery cell 100 along the second direction and facing at least one side of the separator 130.

[0093] For example, the fourth protective member 143 is located on at least one side of the separator 130. The fourth protective member 143 can be attached to the negative electrode 120. After the negative electrode 120 is wound, the fourth protective member 143 is located in the inner ring of the cell 100 and on the side of the negative electrode 120 facing the separator 130. In this way, the thickness of the cell 100 can be adjusted by the fourth protective member 143 to improve the flatness of the cell 100.

[0094] Optional, see Figure 2 and Figure 7 The battery cell 100 also includes a fifth protective element 144. Along the thickness direction of the positive current collector 113, the fifth protective element 144 is disposed on the negative electrode sheet 120 located in the inner ring of the battery cell 100 and facing the separator 130. In this embodiment, the fifth protective element 144 is located in the inner ring of the battery cell 100, and the thickness of the fifth protective element 144 forms the cumulative thickness of the battery cell 100 winding, so as to improve the flatness of the positive electrode sheet 110, the negative electrode sheet 120 and the separator 130 after winding.

[0095] It should be noted that the first protective element 140, the second protective element 141, the third protective element 142, the fourth protective element 143, and the fifth protective element 144 in the embodiments of this application are all insulating elements, such as insulating tape.

[0096] In some embodiments, along the width direction of the positive current collector 113, the edge of the negative current collector has a gap with the edge on the same side of at least one of the third protective member 142, the fourth protective member 143, and the fifth protective member 144; the gap (L) is 0.1-5 mm.

[0097] See Figure 1 and Figure 7 The third protective element 142 covers a portion of the negative electrode 120. A gap exists between the edge of the third protective element 142 and the edge of the negative current collector to prevent the active material at the edge of the negative electrode 120 from falling off during winding, and to prevent burrs formed at the edge of the negative electrode 120 from piercing the separator 130, causing the positive electrode 110 and the negative electrode 120 to come into contact. This prevents a short circuit inside the battery cell 100 and improves the safety of the battery cell 100. The gap (L) between the edge of the third protective element 142 and the edge of the negative current collector on the same side can be 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc., and this embodiment does not require this.

[0098] Similarly, the structure and function of the fourth protective element 143 and the fifth protective element 144 are the same as those of the third protective element 142, and will not be described again.

[0099] In some implementations, see Figure 1 The battery cell 100 also includes a sixth protective element 145, which is disposed on the outer ring of the battery cell 100 and at least partially covers the winding tail 116 of the positive electrode 110. It can be understood that the sixth protective element 145, located at the winding tail 116, provides a fixing effect on the positive electrode 110 located on the outer ring of the battery cell 100, and simultaneously protects the winding tail 116 of the positive electrode 110. Furthermore, the thickness of the sixth protective element 145 contributes to the overall thickness accumulation of the battery cell 100, resulting in a more uniform overall thickness and improved flatness of the battery cell 100.

[0100] In some embodiments, on the positive electrode 110 located on the outer ring of the cell 100, the orthographic projection of at least one of the first tab 111, the second tab 112, and the negative tab structure 122 overlaps with the orthographic projection of the sixth protective member 145. Thus, the sixth protective member 145 extends in various directions of the winding tail 116 of the positive electrode 110, and by combining different extension lengths and widths of the sixth protective member 145, the overall surface of the cell 100 becomes flatter.

[0101] See Figure 2 In some embodiments, the diaphragm 130 has a fold-back section 131 located in the inner ring of the cell 100, and along the second direction, the fold-back section 131 and the negative electrode tab structure 122 located in the inner ring of the cell 100 have overlapping portions.

[0102] In this embodiment, the first tab 111 and the second tab 112 of the positive electrode 110 are located on both sides of the negative tab structure 122, which results in a larger thickness at the first tab 111 and the second tab 112, leading to inconsistent thickness of the cell 100. In this embodiment, the fold-back section 131 of the diaphragm 130 brings the first tab 111 or the second tab 112 closer to the negative tab structure 122, thereby increasing the thickness and ensuring consistent thickness and flatness of the cell 100.

[0103] In some embodiments, the negative electrode active material layer extends to the negative electrode tab 121 along the width direction of the negative electrode current collector; on the negative electrode tab 121, the edge of the negative electrode active material layer is located between the edge of the negative electrode current collector and the edge on the same side of at least one of the third protective member 142, the fourth protective member 143, and the fifth protective member 144.

[0104] It is understandable that the negative electrode active material layer extends to the negative electrode tab 121, increasing the area of ​​the negative electrode active material layer and improving the energy density of the cell 100. The third protective element 142, the fourth protective element 143, and the fifth protective element 144 provide protection for the negative electrode sheet 120. After the cell 100 is wound, the third protective element 142, the fourth protective element 143, and the fifth protective element 144 can prevent the negative electrode active material layer on the negative electrode tab 121 from falling off due to the winding force, thus avoiding a short circuit between the positive electrode sheet 110 and the negative electrode sheet 120, and improving the safety of the cell 100.

[0105] Combination Figure 1 and Figure 2 In some embodiments, the battery cell 100 has a bending region; the fourth protective member 143 is located on the portion of the negative electrode 120 in the bending region; along the second direction, the fourth protective member 143 is offset from the first electrode tab 111 and the second electrode tab 112; along the third direction, the projections of the fourth protective member 143, the first electrode tab 111, and the second electrode tab 112 on the same plane do not overlap. The second direction and the third direction are perpendicular to each other.

[0106] In this embodiment, the fourth protective element 143 and the first tab 111 and the second tab 112 are staggered to balance the thickness of the battery cell 100. At the same time, the projections of the fourth protective element 143, the first tab 111 and the second tab 112 on the same plane do not overlap with each other, so as to reduce the thickness accumulation of the fourth protective element 143 at the first tab 111 and the second tab 112, balance the thickness of the battery cell 100 and make the thickness of the battery cell 100 uniform.

[0107] In some embodiments, the negative electrode 120 includes a single-sided area and an empty foil area located at the winding start end, and the fifth protective member 144 is located in the empty foil area at the winding start end; the projection of the fifth protective member 144 in the thickness direction of the cell 100 overlaps with the winding head 115 of the positive electrode; the projection of the fifth protective member 144 in the thickness direction of the cell 100 and the orthogonal projection of the negative electrode tab 121 on the surface where the fifth protective member 144 is located at least partially overlap. Thus, during the winding process of the cell 100, the fifth protective member 144 provides thickness compensation and support for the negative electrode tab 121 to prevent the negative electrode tab 121 from folding or misaligning.

[0108] The battery cell 100 in this embodiment includes: a positive electrode 110, a separator 130, and a negative electrode 120 wound and stacked together; the negative electrode 120 includes a negative current collector and a negative active material layer located on the negative current collector, and the negative electrode 120 also includes a plurality of negative tabs 121 extending from one side of the negative current collector, the plurality of negative tabs 121 being stacked along a first direction to form a negative tab structure 122; the positive electrode 110 includes a positive current collector 113 and a positive active material layer 114, the positive active material layer 114 being disposed on the thickness side of the positive current collector 113. The positive electrode active material layer 114 has a first empty foil region 1141 and a second empty foil region 1142, which are spaced apart along a first direction. The positive electrode sheet includes a first tab 111 and a second tab 112. The first tab 111 is located in the first empty foil region 1141 and connected to the positive current collector 113, and the second tab 112 is located in the second empty foil region 1142 and connected to the positive current collector 113. The first tab 111 and the second tab 112 are located on both sides of the negative electrode tab structure 122 along a second direction. By setting the first tab 111 and the second tab 112, the width of the positive electrode sheet 110 is increased, and the bending space ratio of the first tab 111, the second tab 112 and the negative electrode tab structure 122 at the top of the cell 100 is reduced. The distance between the cell 100 and the top space of the packaging shell can be further narrowed, thereby increasing the energy density of the cell 100 and increasing the space utilization of the packaging shell. The positive electrode 110 uses the first empty foil area 1141 and the second empty foil area 1142 to weld the first tab 111 and the second tab 112, which can effectively avoid the local overheating that often occurs in multi-tab cells, and can slow down the temperature rise of the cell 100 during the charging and discharging process, ensuring the charging and discharging performance and cycle performance of the cell 100.

[0109] Secondly, embodiments of this application provide a battery, including the battery cell 100 provided in the first aspect of this application.

[0110] The battery in this embodiment includes the cell 100 provided in the first aspect. With such a cell 100, the space ratio of the battery can be reduced and the energy density of the battery can be increased.

[0111] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0112] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0113] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0114] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: A positive electrode (110), a separator (130), and a negative electrode (120) are wound and stacked together; The negative electrode sheet (120) includes a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector. The negative electrode sheet (120) also includes a plurality of negative electrode tabs (121) extending from one side of the negative electrode current collector. The plurality of negative electrode tabs (121) are stacked along a first direction to form a negative electrode tab structure (122). The positive electrode sheet (110) includes a positive current collector (113) and a positive active material layer (114), wherein the positive active material layer (114) is disposed on opposite sides of the positive current collector (113) in the thickness direction; the positive active material layer (114) has a first empty foil region (1141) and a second empty foil region (1142), wherein the first empty foil region (1141) and the second empty foil region (1142) are spaced apart along the first direction; the positive electrode sheet (110) includes a first tab (111) and a second tab (112), the first tab (111) is located in the first empty foil area (1141) and connected to the positive current collector (113), the second tab (112) is located in the second empty foil area (1142) and connected to the positive current collector (113); and the first tab (111) and the second tab (112) are located on both sides of the negative tab structure (122) along the second direction; The first direction and the second direction intersect.

2. The battery cell according to claim 1, characterized in that, The positive electrode (110) has a winding head (115) located on the inner ring of the cell (100) and a winding tail (116) located on the outer ring of the cell (100); The second empty foil area (1142) is located at the winding head (115) or the winding tail (116).

3. The battery cell according to claim 2, characterized in that, There are two first empty foil regions (1141), which are disposed on opposite sides of the positive electrode current collector (113) along the thickness direction of the positive electrode current collector (113); the first electrode tab (111) is located in one of the two first empty foil regions (1141); Alternatively, along the thickness direction of the positive current collector (113), the orthographic projection of the first empty foil area (1141) on the surface where the positive current collector (113) is located overlaps with the orthographic projection of the positive active material layer (114) on the side surface of the positive current collector (113) away from the first empty foil area (1141) on the surface where the positive current collector (113) is located.

4. The battery cell according to any one of claims 1-3, characterized in that, The positive electrode active material layer (114) has a first groove, the first groove and the first electrode tab (111) are correspondingly arranged, the first empty foil area (1141) is exposed from the first groove, and the first electrode tab (111) is located in the first groove; And / or, the positive electrode active material layer (114) has a second groove, the second groove and the second tab (112) are positioned correspondingly, the second empty foil area (1142) is exposed from the second groove, and the second tab (112) is located in the second groove.

5. The battery cell according to claim 4, characterized in that, The positive electrode (110) has a first notch (117), and along the width direction of the positive current collector (113), the first notch (117) and the first groove are disposed opposite to each other on both sides of the positive electrode (110); And / or, the positive electrode (110) has a second notch (118) along the width direction of the positive current collector (113), and the second notch (118) and the second groove are disposed opposite to each other on both sides of the positive electrode (110).

6. The battery cell according to any one of claims 1-3, characterized in that, It also includes a first protective element (140), which is provided in a one-to-one correspondence with the first empty foil area (1141), and at least part of the first protective element (140) covers the first empty foil area (1141); And / or, the battery cell (100) includes a second protective element (141), the second protective element (141) and the second empty foil area (1142) are provided in a one-to-one correspondence, and at least part of the first protective element (140) covers the second empty foil area (1142).

7. The battery cell according to any one of claims 1-3, characterized in that, It also includes at least one of the following: The battery cell (100) also includes a plurality of third protective components (142), which are respectively disposed on the side of the negative electrode (120) facing the first electrode tab (111) and the second electrode tab (112); The battery cell (100) further includes a fourth protective member (143), which is disposed on the negative electrode plate (120) located in the inner ring of the battery cell (100) along the second direction and facing at least one side of the separator (130); The cell (100) also includes a fifth protective element (144), which is disposed on the negative electrode sheet (120) located in the inner ring of the cell (100) along the thickness direction of the positive current collector (113) and facing the side of the separator (130). The cell (100) also includes a sixth protective element (145), which is disposed on the outer ring of the cell (100) and at least partially covers the winding tail (116) of the positive electrode (110).

8. The battery cell according to claim 7, characterized in that, On the positive electrode plate (110) located on the outer ring of the cell (100), the orthographic projection of at least one of the first tab (111), the second tab (112) and the negative tab structure (122) overlaps with the orthographic projection of the sixth protective member (145).

9. The battery cell according to claim 7, characterized in that, Along the width direction of the positive current collector (113), the edge of the negative current collector has a gap with the edge on the same side of at least one of the third protective member (142), the fourth protective member (143), and the fifth protective member (144); the gap is 0.1 mm to 5 mm.

10. The battery cell according to claim 9, characterized in that, Along the width direction of the negative electrode current collector, the negative electrode active material layer extends to the negative electrode tab (121); On the negative electrode tab (121), the edge of the negative electrode active material layer is located between the edge of the negative electrode current collector and the edge on the same side of at least one of the third protective member (142), the fourth protective member (143), and the fifth protective member (144).

11. The battery cell according to claim 7, characterized in that, The battery cell (100) has a bending area; The fourth protective element (143) is located in the portion of the negative electrode sheet (120) in the bending area; along the second direction, the fourth protective element (143) is offset from the first electrode tab (111) and the second electrode tab (112); along the third direction, the projections of the fourth protective element (143), the first electrode tab (111), and the second electrode tab (112) on the same plane do not overlap with each other; The second direction and the third direction are perpendicular to each other.

12. The battery cell according to claim 7, characterized in that, The negative electrode sheet (120) includes a single-sided area and an empty foil area located at the beginning of the winding, and the fifth protective member (144) is located in the empty foil area at the beginning of the winding. The projection of the fifth protective element (144) in the thickness direction of the cell (100) overlaps with the winding head (115) of the positive electrode (110); The projection of the fifth protective element (144) in the thickness direction of the cell (100) and the orthogonal projection of the negative electrode tab (121) on the surface where the fifth protective element (144) is located at least partially overlap.

13. The battery cell according to any one of claims 1-3, characterized in that, The diaphragm (130) has a fold-back section (131) located in the inner ring of the cell (100) and, along the second direction, the fold-back section (131) and the negative electrode tab structure (122) located in the inner ring of the cell (100) have overlapping portions.

14. A battery, characterized in that, Includes the battery cell (100) as described in any one of claims 1-13.

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