Battery cell and battery

Abstract

The utility model discloses a battery cell and battery, the battery cell includes: a battery cell body including a first pole piece, a second pole piece and a diaphragm, the polarity of the first pole piece is opposite to that of the second pole piece, the first pole piece, the diaphragm and the second pole piece are laminated and then wound to form the battery cell body; the first pole piece comprises a first current collector and a first active layer coated on the surface of the first current collector, an empty foil area not coated with the first active layer is arranged on the first current collector, and the second pole piece comprises a second current collector and a second active layer coated on the surface of the second current collector. A plurality of second soft tabs are arranged on the second current collector; and a first electrode adapter and a second electrode adapter, the first electrode adapter is connected with the empty foil area, and the second electrode adapter is connected with the second soft tab. According to the battery cell disclosed by the utility model, the charging rate can be increased while the energy density of the battery is improved.

Description

Technical Field

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

[0002] With the continuous advancement of electronic information technology, consumers are placing higher demands on the performance and functionality of electronic devices. Smartphones, tablets, laptops, and wearable devices are playing an increasingly important role in our daily lives. The trend towards multifunctionality and intelligence in these devices is leading to ever-increasing requirements for battery performance.

[0003] Against this backdrop, battery technology faces two main challenges: first, how to increase battery capacity within limited size and weight to meet the demands of prolonged, high-intensity device use; and second, how to accelerate battery charging speed to reduce user waiting time and improve efficiency. Traditional battery technologies often struggle to meet both requirements simultaneously. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one objective of this invention is to provide a battery cell and battery in which only one empty foil area connected to the first electrode adapter is provided on the first electrode, thereby increasing the energy density of the battery cell. Simultaneously, multiple second soft tabs are provided on the second electrode, reducing the length of the current flow path within the battery cell and accelerating the charging speed.

[0005] In a first aspect, embodiments of the present invention provide a battery cell, comprising:

[0006] The battery cell body includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities. The first electrode, the separator, and the second electrode are stacked and then wound to form the battery cell body. The first electrode includes a first current collector and a first active layer coated on the surface of the first current collector. The first current collector has an empty foil area that is not coated with the first active layer. The second electrode includes a second current collector and a second active layer coated on the surface of the second current collector. The second current collector has a plurality of second flexible tabs. A first electrode adapter and a second electrode adapter are also included. The first electrode adapter is connected to the empty foil area, and the second electrode adapter is connected to the second flexible tabs.

[0007] Multiple second soft tabs are stacked along a second direction to form second tabs. The second tabs are connected to the second electrode component, and the first electrode adapter is connected to the empty foil area. The battery cell of this utility model is formed by winding a first electrode sheet and a second electrode sheet. Both the first electrode sheet and the second electrode sheet are integral structures. Only one empty foil area connected to the first electrode adapter is provided on the first electrode sheet. The first electrode sheet can have more first active layers, thereby improving the energy density of the battery and reducing the width of the positive electrode sheet, thereby reducing the space ratio of the positive tab structure after bending on the positive electrode sheet. This allows the distance between the battery cell and the top surface of the packaging shell to be reduced during packaging, further improving the energy density of the battery cell and the space utilization of the shell. On the other hand, the multiple second soft tabs on the integral second electrode sheet help to reduce the current transmission path length in the battery cell and improve charging efficiency. In addition, the design of multiple second soft tabs on the second electrode sheet can also make the current distribution on the second electrode sheet more uniform, reduce local overheating, thereby further improving the charging speed and extending the service life of the battery cell.

[0008] In some embodiments, the cell body includes a first bending region and a second bending region formed by winding, the first bending region and the second bending region being opposite each other along a first direction, the second current collector including a first single-sided coated section and a first double-sided coated section connected sequentially in a winding order, the second active layer including a second outer active layer and a second inner active layer, the outer sides of the first single-sided coated section and the first double-sided coated section are coated with the second outer active layer, the inner side of the first double-sided coated section is coated with the second inner active layer, the end of the first single-sided coated section away from the first double-sided coated section constitutes the winding start end of the second current collector, the winding start end of the second current collector is located between the first bending region and the second bending region, the second outer active layer extends beyond the first bending region in the winding direction, and the first single-sided coated section has at least one second soft tab.

[0009] According to some embodiments of the present invention, the first single-sided coating section of the second current collector includes a first bent portion and a second bent portion formed by sequential winding. The first bent portion is located in the first bent area of ​​the battery cell body, and the second bent portion is located in the second bent area of ​​the battery cell body. The starting point of the second outer active layer of the second current collector extends beyond the first bent portion, and the distance A1 between the starting point of the second outer active layer and the center of the first bent portion along the first direction satisfies: A1 > 0 mm.

[0010] According to some embodiments of the present invention, the region of the first single-sided coated section located between the first bent portion and the second bent portion is provided with at least one second soft electrode tab, and / or,

[0011] The width W1 of the second soft electrode tab along the first direction and the width W2 of the second electrode adapter along the first direction satisfy the following condition: W1 / W2≥1.1.

[0012] According to some embodiments of the present invention, the first double-sided coating section includes a third bend formed outside the first bend, the starting point of the second inner active layer extends beyond the third bend, and the distance A2 between the center of the third bend and the starting point of the second inner active layer satisfies: A2 > 0 mm.

[0013] According to some embodiments of the present invention, the projection of the starting point of the second outer active layer in the reference plane is spaced apart from the projection of the starting end of the first electrode in the reference plane, and the starting end of the first electrode is located on the side of the starting point of the second outer active layer facing the second bending area, and the first direction and the third direction together define the reference plane.

[0014] According to some embodiments of the present invention, the projection of the winding start end of the second current collector in the reference plane is spaced apart from the projection of the empty foil area in the reference plane, and the empty foil area is located on the side of the empty foil area of ​​the second current collector facing the second bending area.

[0015] According to some embodiments of this utility model, the surface of the second active layer is provided with grooves, the width A3 of which satisfies: 0.01mm≤A3≤0.2mm, and / or, the spacing A4 between two adjacent grooves along the first direction satisfies: 0.5mm≤A4≤2mm, and / or,

[0016] The distance A5 between the end of the groove along the third direction and the edge of the second active layer along the third direction satisfies: 0.05mm ≤ A5 ≤ 3mm, and / or,

[0017] The spacing A6 between the groove closest to the edge of the second active layer along the first direction and the edge of the second active layer along the first direction satisfies: 0.05mm ≤ A6 ≤ 3mm, and / or,

[0018] The first active layer is provided with a plurality of grooves at intervals along the first direction. The plurality of grooves are respectively located in the first bending area and the second bending area. The depth D1 of the grooves along the second direction satisfies: 5μm≤D1≤100μm.

[0019] According to some embodiments of the present invention, the empty foil area has the second soft electrode tab on both sides along the second direction.

[0020] In some embodiments, the first electrode includes a first edge region and a first body region, the thickness difference between the first edge region and the first body region not exceeding 15 μm, and / or the second electrode includes a second edge region and a second body region, the thickness difference between the second edge region and the second body region not exceeding 20 μm.

[0021] In some embodiments, the first current collector includes a second single-sided coating section and a second double-sided coating section. The first active layer is coated on one side of the second single-sided coating section facing the inside of the cell body, and the first active layer is coated on both sides of the second double-sided coating section. A safety layer is coated on the first active layer on the second single-sided coating section, and the thickness of the safety layer is 1-20 μm.

[0022] According to some embodiments of the present invention, the material of the safety layer includes at least one of SiO2, PPA, or PVDF.

[0023] In some embodiments, the first electrode adapter includes a first solder mark formed by welding to the empty foil area, the first electrode sheet is provided with a first protective adhesive, the first protective adhesive at least covers the first solder mark, and / or, the second electrode adapter includes a second solder mark formed by welding to the second electrode tab, the second electrode adapter is provided with a second protective adhesive, the second protective adhesive covers the second solder mark.

[0024] According to some embodiments of the present invention, the first protective adhesive extends beyond the edge of the first electrode sheet along a third direction, the second protective adhesive extends along the first direction, and the first protective adhesive and the second protective adhesive partially overlap.

[0025] According to some embodiments of the present invention, a third protective adhesive is provided on the second electrode sheet, the third protective adhesive is opposite to the first protective adhesive along the first direction, the third protective adhesive separates the first electrode sheet and the second electrode sheet, and the third protective adhesive is spaced apart from the second soft electrode tab.

[0026] According to some embodiments of the present invention, a fourth protective adhesive is also included, which is applied to the outer surface of the battery cell body and covers one end of the second single-sided coating section of the first current collector that is opposite to the second double-sided coating section.

[0027] According to some embodiments of the present invention, the projection of the empty foil area in the reference plane is spaced apart from the projection of the end of the fourth protective adhesive near the first bending area of ​​the cell body in the reference plane, and the empty foil area is located on the side of the fourth protective adhesive near the first bending area away from the second bending area.

[0028] Secondly, embodiments of the present invention provide a battery, comprising: an outer casing; and a battery cell as described in any of the preceding claims, wherein the outer casing covers the battery cell.

[0029] The battery of this invention, due to the use of the aforementioned battery cell, has higher energy density and longer battery life. During charging, the current path is shorter, the current distribution is more uniform, and the charging speed is faster.

[0030] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention;

[0033] Figure 2 This is a cross-sectional schematic diagram of the battery cell according to an embodiment of the present invention;

[0034] Figure 3 This is one of the schematic diagrams of the unfolded structure of the second pole piece in an embodiment of this utility model;

[0035] Figure 4 This is the second schematic diagram of the unfolded structure of the second pole piece in an embodiment of this utility model;

[0036] Figure 5 This is the third schematic diagram of the unfolded structure of the second pole piece in this embodiment of the present invention;

[0037] Figure 6 This is the fourth schematic diagram of the unfolded structure of the second pole piece in this embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the unfolded structure of the first pole piece according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the structure of the first electrode sheet in an embodiment of this utility model;

[0040] Figure 9 This is a schematic diagram of the structure of the second electrode sheet in an embodiment of this utility model;

[0041] Figure 10 This is a schematic diagram of the structure of the empty foil area on the first electrode plate of the battery cell body according to an embodiment of the present invention.

[0042] Figure label:

[0043] 100-cell;

[0044] 110 - Battery cell body; 111 - First bending area; 112 - Second bending area;

[0045] 120 - First electrode; 120a - First edge region; 120b - First main body region; 121 - First current collector; 1211 - Second single-sided coating section; 1212 - Second double-sided coating section; 122 - First active layer; 123 - Empty foil region; 124 - Groove; 125 - First protective adhesive;

[0046] 130 - Second electrode sheet; 130a - Second edge region; 130b - Second main body region; 131 - Second current collector; 1311 - First single-sided coating section; 1311a - First bending section; 1311b - Second bending section; 1312 - First double-sided coating section; 1312a - Third bending section; 132 - Second active layer; 1321 - Second outer active layer; 1322 - Second inner active layer; 133 - Second soft electrode tab; 135 - Wire groove; 136 - Third protective adhesive;

[0047] 140 - Diaphragm;

[0048] 150 - First electrode adapter;

[0049] 160 - Second electrode adapter; 161 - Second solder mark; 162 - Second protective adhesive;

[0050] 170 - Fourth protective adhesive. Detailed Implementation

[0051] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0052] Existing battery technology faces two main challenges: first, how to increase battery capacity within limited size and weight to meet the demands of prolonged, high-intensity device use; and second, how to accelerate battery charging speed to reduce user waiting time and improve efficiency. Traditional battery technologies often struggle to meet these requirements simultaneously, making innovative battery technologies and charging methods a hot topic in research and development.

[0053] In view of this, the present invention proposes a battery cell and battery, wherein only one empty foil area connected to the first electrode adapter is provided on the first electrode plate, thereby improving the energy density of the battery cell. At the same time, multiple second soft tabs are provided on the second electrode plate, thereby reducing the length of the current flow path in the battery cell and accelerating the charging speed.

[0054] For ease of explanation, please refer to... Figure 1 The first direction can be the X direction, the second direction can be the Y direction, and the third direction can be the Z direction.

[0055] The following is for reference. Figures 1 to 10 This invention describes a battery cell 100 according to a first aspect of the present invention. The battery cell 100 may include a battery cell body 110, a first electrode adapter 150, and a second electrode adapter 160. The battery cell body 110 may include a first electrode 120, a second electrode 130, and a separator 140.

[0056] The first electrode 120 and the second electrode 130 have opposite polarities. For example, the first electrode 120 can be a positive electrode and the second electrode 130 can be a negative electrode, or the first electrode 120 can be a negative electrode and the second electrode 130 can be a positive electrode. The first electrode 120, the separator 140, and the second electrode 130 are stacked and then wound to form the battery cell body 110.

[0057] refer to Figure 1 and Figure 2 The first electrode 120 may include a first current collector 121 and a first active layer 122 coated on the surface of the first current collector 121. The first current collector 121 has an empty foil area 123 that is not coated with the first active layer 122. The empty foil area 123 can serve as the tab of the first electrode 120. In this way, the first electrode 120 can be directly connected to the first electrode adapter 150 to supply power to the outside through the empty foil area 123. Furthermore, since the empty foil area 123 that serves as the tab has a smaller proportion of the area of ​​the first current collector 121, it is equivalent to increasing the coating area of ​​the first active layer 122 on the first current collector 121 and increasing the amount of the first active layer 122, which is beneficial to improving the energy density of the battery cell 100.

[0058] The second electrode 130 may include a second current collector 131 and a second active layer 132 coated on the surface of the second current collector 131. The second current collector 131 has a plurality of second flexible tabs 133, which can be stacked for better current collection and connection to the second electrode adapter 160. The second flexible tabs 133 may be located at one end of the second electrode 130 along a third direction. (Refer to...) Figure 4 In the unfolded state, the second flexible tabs 133 are spaced apart along the second direction. This allows sufficient second active layers 132 to be coated on the second electrode 130 to improve the energy density of the cell 100. At the same time, the arrangement of multiple second flexible tabs 133 on one second electrode 130 helps to reduce the length of the current path, thereby accelerating the charging rate of the battery.

[0059] The first electrode adapter 150 is connected to the empty foil area 123, and the second electrode adapter 160 is connected to the second soft electrode tab 133, so as to connect to the circuit of external electrical equipment or charging equipment through the first electrode adapter 150 and the second electrode adapter 160.

[0060] The second flexible tab 133 is disposed on the straight section of the second electrode 130 between the first bending region 111 and the second bending region 112, forming multiple currents. Multiple second flexible tabs 133 are stacked along the second direction to form a second tab. The second tab is connected to the second electrode component, and the first electrode adapter 150 is connected to the empty foil region 123. In this way, the structural stability and reliability of the battery cell 100 are improved.

[0061] It should be noted that the connection between the second tab and the second electrode, and the connection between the electrode adapter and the empty foil area, can be achieved through conventional laser welding, ultrasonic welding, resistance welding, or electrical connection via conductive adhesive.

[0062] The battery cell 100 of this invention is formed by winding a first electrode 120 and a second electrode 130. Both the first electrode 120 and the second electrode 130 are integral structures. The first electrode 120 has only one empty foil area 123 connected to the first electrode adapter 150. The first electrode 120 can have more first active layers 122, thereby increasing the energy density of the battery and reducing the width of the positive electrode, thereby reducing the space ratio of the positive electrode tab structure after bending. This allows the distance between the battery cell and the top surface of the packaging shell to be reduced during packaging, further improving the energy density of the battery cell and the space utilization of the shell. On the other hand, the second electrode 130 has multiple second soft tabs 133, which helps to reduce the path length of the current in the battery cell 100 and improves the charging efficiency. In addition, the design of multiple second soft tabs 133 on the second electrode 130 can also make the current distribution on the second electrode 130 more uniform, reduce local overheating, thereby further improving the charging speed and extending the service life of the battery cell 100.

[0063] refer to Figure 1 and Figure 10 In some embodiments, the cell body 110 includes a first bending region 111 and a second bending region 112 formed by winding. The first bending region 111 and the second bending region 112 are opposite to each other along a first direction. The first bending region and the second bending region are connected by a straight section of a first electrode 120 and a straight section of a second electrode 130 that are spaced apart along a second direction.

[0064] The second current collector 131 may include a first single-sided coating section 1311 and a first double-sided coating section 1312 connected sequentially in a winding order, wherein the winding direction can be counterclockwise or clockwise. In other words, during the winding process, the first single-sided coating section 1311 is the area on the second current collector 131 that is wound first, and the first double-sided coating section 1312 is the area on the second current collector 131 that is wound later. Correspondingly, the ring formed by the first single-sided coating section 1311 is positioned on the inner side compared to the ring formed by the first double-sided coating section 1312.

[0065] refer to Figure 2 When the first electrode 120, the separator 140, and the second electrode 130 are stacked and wound, in order to ensure the overall structural stability of the battery cell 100 formed by the winding, and while ensuring the separation effect of the separator 140 on the first electrode 120 and the second electrode 130, the winding starting ends of the first electrode 120, the separator 140, and the second electrode 130 are staggered along a first direction. In other words, one of the first electrode 120 and the second electrode 130 will be wound to form the innermost ring of the battery cell body 110, and the other will form the outermost ring of the battery cell 100. The outermost electrode forms the outer wall of the battery cell body 110. In this embodiment, the second electrode 130 can form the innermost ring of the battery cell body 110, and the first electrode 120 can form the outermost ring of the battery cell body 110.

[0066] refer to Figure 2 The second active layer 132 may include a second outer active layer 1321 and a second inner active layer 1322. The outer sides of the first single-sided coating section 1311 and the first double-sided coating section 1312 are coated with the second outer active layer 1321, and the inner side of the first double-sided coating section 1312 is coated with the second inner active layer 1322. The end of the first single-sided coating section 1311 that is away from the first double-sided coating section 1312 constitutes the winding start end of the second current collector 131. The winding start end of the second current collector 131 is located between the first bending region 111 and the second bending region 112. In other words, the first single-sided coating section 1311 constitutes the innermost ring of the aforementioned cell body 110. The inner side of the first single-sided coating section 1311 is not coated with the second inner active layer 1322. On the one hand, this can reduce the breakage and detachment of the second inner active layer 1322 due to the large bending angle. On the other hand, it can increase the utilization rate of the internal space of the cell body 110, thereby improving the energy density of the cell 100. In addition, it is also beneficial to improve the overall flatness of the cell body 110.

[0067] refer to Figure 2The second outer active layer 1321 extends beyond the first bending region 111 in the winding direction (e.g., clockwise), meaning the starting point of the second outer active layer 1321 is located upstream of the first bending region 111 in the winding direction. The first single-sided coated section 1311 has at least one second soft tab 133. Since the first single-sided coated section 1311 constitutes the innermost ring of the cell body 110, and the first single-sided coated section 1311 is almost folded during winding, it may break. By having at least one second soft tab 133, the first single-sided coated section 1311 can ensure that it can still undergo an electrochemical reaction with the first electrode 120 even when it breaks, thereby improving the reliability of the cell 100 during use.

[0068] According to some embodiments of the present invention, the first single-sided coating segment 1311 includes a first bent portion 1311a and a second bent portion 1311b formed by sequential winding. The first bent portion 1311a is located in the first bent region 111, and the second bent portion 1311b is located in the second bent region 112. The starting point of the second outer active layer 1321 (e.g., Figure 2 Point a shown extends beyond the first bend 1311a, and the distance A1 between the starting point of the second outer active layer 1321 and the center of the first bend 1311a along the first direction satisfies: A1 > 0 mm. Preferably, A2 can be 0.5 mm to 10 mm, for example, A2 can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. The starting end of the first electrode 120 ( Figure 2 Point c shown is opposite to the outermost outer ring of the innermost ring of the cell body 110 formed by the first single-sided coating section 1311. In the winding direction, the second outer active layer 1321 is located before the first bend 1311a formed by the first bend of the first single-sided coating section 1311. In this way, the first active layer 122 facing the first single-sided coating section 1311 at the starting end of the first electrode 120 is opposite to the second active layer 132, which improves the flow path of current between the first electrode 120 and the second electrode 130. At the same time, the second outer active layer 1321 can also make up for the thickness difference formed by bending on the cell body 110 at the first bend 1311a, improve the flatness of the cell 100, and thus improve the stability of the cell 100.

[0069] refer to Figure 2 and Figure 4According to some embodiments of this utility model, at least one second soft tab 133 is provided in the region between the first bent portion 1311a and the second bent portion 1311b of the first single-sided coating section 1311. Thus, when the first single-sided coating section 1311 of the innermost ring of the cell body 110, where the second electrode 130 begins to bend, breaks at the second bent portion 1311b, the second soft tab 133, located in the region between the first bent portion 1311a and the second bent portion 1311b, can still normally undergo an electrochemical reaction with the first electrode 120 at the broken portion of the first single-sided coating section 1311, improving the reliability of the battery.

[0070] The width W1 of the second flexible tab 133 along the first direction and the width W2 of the second electrode adapter 160 along the first direction satisfy the condition: W1 / W2≥1.1. Thus, even when multiple second flexible tabs 133 are stacked and welded to the second electrode adapter 160, and misalignment occurs in the second flexible tabs 133, they can still be welded to the second electrode adapter 160, improving the battery's overcurrent capability.

[0071] refer to Figure 2 According to some embodiments of the present invention, the first double-sided coated section 1312 includes a third bent portion 1312a formed outside the first bent portion 1311a, and the starting point of the second inner active layer 1322 ( Figure 2 Point b shown extends beyond the third bend 1312a. The distance A2 between the center of the third bend 1312a and the starting point of the second inner active layer 1322 satisfies: A2 > 0 mm. Preferably, A2 can be 0.5 mm to 10 mm, for example, A2 can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. The starting end of the first electrode 120 ( Figure 2 Point c shown is opposite to the outermost outer edge of the innermost ring of the cell body 110 formed by the first single-sided coating section 1311. The second inner active layer 1322 starts at the end of the innermost ring of the cell body 110. In this way, the starting end of the first electrode 120 is opposite to the first active layer 122 inside the cell 100 and the second inner active layer 1322 are opposite, which improves the flow path of current between the first electrode 120 and the second electrode 130. At the same time, the second inner active layer 1322 can also make up for the thickness difference formed by bending on the cell body 110 at the third bend 1312a, improve the flatness of the cell 100, and thus improve the stability of the cell 100.

[0072] According to some embodiments of this utility model, the starting point of the second outer active layer 1321 ( Figure 2The projection of point b shown in the reference plane onto the starting end of the first pole piece 120 ( Figure 2 The projection intervals of point c in the reference plane are arranged, and the starting end of the first electrode 120 is located on the side of the starting point of the second outer active layer 1321 facing the second bending region 112. The first direction and the third direction together define the reference plane, that is, the reference plane can be parallel to the XZ plane. In this way, unnecessary overlap between the second inner active layer 1322 and the first electrode 120 in the thickness (second direction) of the cell 100 is reduced, and the flatness of the cell 100 in the thickness direction is improved.

[0073] According to some embodiments of the present invention, the winding start end of the second current collector 131 ( Figure 2 The projection of point d in the reference plane is spaced apart from the projection of the empty foil area 123 in the reference plane, and the empty foil area 123 is located on the side of the empty foil area 123 of the second current collector 131 facing the second bending area 112. In this way, the starting end of the second current collector 131 is not opposite to the empty foil area 123 in the second direction, which improves the flatness of both sides of the cell body 110 along the first direction. At the same time, it also increases the area occupied by the structure with the opposing first active layer 122 and second active layer 132 in the cell body 110, thereby improving the energy density of the cell 100.

[0074] refer to Figure 3 , Figure 5 and Figure 6 According to some embodiments of this utility model, a groove 135 is formed on the surface of the second active layer 132. The groove 135 increases the surface area of ​​the second active layer 132 of the second electrode 130, which is beneficial to improving the electrochemical reaction rate of the cell 100, thereby improving battery performance. The width A3 of the groove 135 satisfies: 0.01mm ≤ A3 ≤ 0.2mm. For example, the width A3 of the groove 135 can be 0.01mm, 0.05mm, 0.1mm, 0.15mm, or 2mm. Of course, the width A3 of the groove 135 can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0075] In this way, on the one hand, the groove 135 is not too narrow (e.g., less than 0.01mm), which would not be able to increase the surface area of ​​the second active layer 132. On the other hand, the groove 135 is not too wide (e.g., more than 2mm), which would reduce the active material of the second active layer 132 and affect the performance of the battery.

[0076] The spacing A4 between two adjacent wire grooves 135 along the first direction satisfies: 0.5mm ≤ A4 ≤ 2mm. For example, A4 can be 0.5mm, 1mm, 1.5mm, or 2mm. Of course, the spacing A4 between wire grooves 135 can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0077] Thus, on the one hand, it avoids the spacing between the grooves 135 being too small (e.g., less than 0.5mm), which would result in an excessively high density of the grooves 135, leading to excessive loss of active material in the second active layer 132 and affecting battery performance. On the other hand, it avoids the spacing between the grooves 135 being too large (e.g., more than 2mm), which would result in an overly dispersed arrangement of the grooves 135, reducing the surface area of ​​the second active layer 132 and thus having a smaller effect on improving battery performance.

[0078] refer to Figure 3 , Figure 5 and Figure 6 According to some embodiments of this utility model, the value A5 between the end of the groove 135 along the third direction and the edge of the second active layer 132 along the third direction satisfies: 0.05mm ≤ A5 ≤ 3mm. For example, A5 can be 0.05mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, or 3mm. Of course, A5 can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0079] In this way, the two ends of the wire groove 135 along the third direction (the height direction of the cell 100) do not penetrate the second active layer 132, do not break the second active layer 132, and prevent the active material between two adjacent wire grooves 135 from falling off the second current collector 131, thereby enhancing the integrity of the second electrode 130 and extending the battery's service life.

[0080] The spacing A6 between the groove 135 closest to the edge of the second active layer 132 along the first direction and the edge of the second active layer 132 along the first direction satisfies the following condition: 0.05mm ≤ A6 ≤ 3mm. For example, A6 can be 0.05mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, or 3mm. Of course, A6 can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0081] This ensures that there is a suitable distance between the end of the groove 135 along the first direction and the edge of the second active layer 132, so that the second active layer 132 has sufficient adhesion to prevent the active material of the second active layer 132 from falling off the second current collector 131 while ensuring improved battery performance.

[0082] refer to Figure 1 and Figure 7In some embodiments, the first active layer 122 is provided with a plurality of grooves 124 spaced apart along a first direction. The plurality of grooves 124 are respectively located in the first bending region 111 and the second bending region 112. The depth D1 of the grooves 124 along the second direction satisfies: 5μm≤D1≤100μm. For example, D1 can be 5μm, 20μm, 40μm, 60μm, 80μm or 100μm. Of course, D1 can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0083] Thus, by setting the groove 124, the stress concentration at the bending point of the first electrode 120 during the winding process is reduced, which helps to improve the structural stability of the cell body 110 and makes the stress on the cell body 110 more uniform, thereby avoiding the occurrence of black spot lithium plating. In addition, the groove 124 can also make the bending point of the first electrode 120 fit more tightly with the inner second electrode 130 during bending, increasing the winding tightness of the cell body 110 and helping to improve the energy density of the cell body 110.

[0084] refer to Figure 1 According to some embodiments of this utility model, the empty foil region 123 has second soft tabs 133 on both sides along the second direction. In this way, during the charging process, the empty foil region 123, which serves as the positive electrode of the battery, can form a current path with the second soft tabs 133 on both sides, which serve as the negative electrodes, thus helping to further improve the charging rate of the battery.

[0085] refer to Figure 8 and Figure 9 In some embodiments, the first electrode 120 includes a first edge region 120a and a first main region 120b, which are connected along a third direction. The first edge region 120a may be the end region in the active layer coating process. The thickness difference between the first edge region 120a and the first main region 120b does not exceed 15 μm. The second electrode 130 includes a second edge region 130a and a second main region 130b, and the thickness difference between the second edge region 130a and the second main region 130b does not exceed 20 μm. In the electrode manufacturing process, the active layer is coated onto the current collector using a coating device. Due to the tailing effect, the edge region located at the end of the coating process will have a certain degree of thinning compared to the main region of the electrode. In this embodiment, by limiting the thickness difference between the first edge region 120a and the first main body region 120b of the first electrode 120 and the thickness difference between the second edge region 130a and the second main body region 130b of the second electrode 130, the influence of the trailing effect is reduced, the uniformity of the first electrode 120 and the second electrode 130 in the thickness direction is improved, and thus the overall performance of the battery is improved.

[0086] In some embodiments, the first current collector 121 includes a second single-sided coating section 1211 and a second double-sided coating section 1212. The surface of the second single-sided coating section 1211 facing the inside of the cell body 110 is coated with a first active layer 122, and both sides of the second double-sided coating section 1212 are coated with the first active layer 122. The second single-sided coating section 1211 constitutes the outermost ring of the cell body 110, that is, the side of the second single-sided coating section 1211 facing the outside of the cell 100 is the outer wall of the cell body 110, and the first active layer 122 is not coated thereon.

[0087] The first active layer 122 on the second single-sided coating section 1211 is coated with a safety layer, the thickness of which is 1-20 μm. For example, the thickness of the safety layer can be 1 μm, 5 μm, 10 μm, 15 μm, or 20 μm. Of course, the thickness of the safety layer can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0088] In this way, the safety layer provides physical protection for the battery cell 100, reducing the possibility of thermal runaway or short circuit when the battery cell 100 is subjected to external mechanical stress.

[0089] According to some embodiments of this utility model, the safety layer material includes at least one of SiO2, PPA (polyamic acid), or PVDF (polyvinylidene fluoride). Exemplarily, the safety layer material can be a combination of SiO2 and PPA. Both SiO2 and PPA have electrical insulation properties, preventing internal short circuits in the battery and improving the battery's furnace temperature performance. SiO2 provides mechanical strength to the safety layer, while PPA can be converted into polyimide (PI) at high temperatures, providing excellent heat resistance and mechanical properties to the safety layer, while maintaining good flexibility and adhesion. Alternatively, the safety layer material can also be a combination of SiO2 and PVDF. Both SiO2 and PVDF have electrical insulation properties, preventing internal short circuits in the battery. SiO2 provides mechanical strength to the safety layer, while PVDF has good chemical stability and adhesion, allowing it to bond well with other materials, while also providing a certain degree of flexibility to the safety layer. Of course, the safety layer can also be other combinations of the above-mentioned materials.

[0090] In some embodiments, the first electrode adapter 150 includes a first solder mark formed by welding with the empty foil area 123, and a first protective adhesive 125 is provided on the first electrode 120. The first protective adhesive 125 at least covers the first solder mark. The first protective adhesive 125 improves the connection stability between the first electrode adapter 150 and the first electrode 120 and avoids interference between the first solder mark and the second electrode 130.

[0091] The second electrode adapter 160 may include a second solder mark 161 formed by welding with the second electrode tab. The second electrode adapter 160 is provided with a second protective adhesive 162, which covers the second solder mark 161. The first protective adhesive 125 improves the connection stability between the second electrode adapter 160 and the second electrode tab, preventing the second flexible electrode tab 133 of the second electrode tab from detaching from the second electrode adapter 160, thereby improving the structural stability of the battery cell 100.

[0092] refer to Figure 1 According to some embodiments of this utility model, the first protective adhesive 125 extends beyond the edge of the first electrode 120 along a third direction, and the second protective adhesive 162 extends along a first direction, with the first protective adhesive 125 and the second protective adhesive 162 partially overlapping. When the distance between the first electrode adapter 150 and the second electrode adapter 160 along the first direction is small, the first protective adhesive 125 and the second protective adhesive 162 partially overlap, improving the overall integrity of the battery cell 100. At the same time, the first protective adhesive 125 and the second protective adhesive 162 can also be attached to one end of the battery cell 100 where the second electrode tab is located, thereby improving the uniformity of the thickness of the battery cell 100.

[0093] According to some embodiments of this utility model, a third protective adhesive 136 is provided on the second electrode 130. The third protective adhesive 136 is opposite to the first protective adhesive 125 along a first direction, and the third protective adhesive 136 separates the first electrode 120 and the second electrode 130. In this way, interference between the first electrode adapter 150 and the second electrode 130 is avoided after the first electrode adapter 150 is connected to the first electrode 120.

[0094] Understandably, when the second soft electrode tab 133 on the second electrode 130 is laminated and welded to the second electrode adapter 160, the second soft electrode tab 133 will bend in the second direction. In order to avoid interference with the bending process of the second soft electrode tab 133, the third protective adhesive 136 is spaced apart from the second soft electrode tab 133.

[0095] refer to Figure 1 According to some embodiments of the present invention, the starting end of the diaphragm 140 is covered (e.g.) Figure 2 Point f (as shown) is the starting end of the winding of the second current collector 131, and the starting end of the separator 140 extends along the first direction, with the starting end of the separator 140 spaced apart from the second bending area 112. This ensures the separation effect of the separator 140 on the first electrode 120 and the second electrode 130, while also preventing the starting end of the separator 140 from occupying too much space in the innermost ring of the cell 100, thus improving the space utilization within the cell body 110 and contributing to increased energy density of the cell 100.

[0096] According to some embodiments of this utility model, a fourth protective adhesive 170 is also included. The fourth protective adhesive 170 is applied to the outer surface of the cell body 110, and the fourth protective adhesive 170 covers the end of the second single-sided coating section 1211 of the first current collector 121 that is opposite to the second double-sided coating section 1212. In this way, by using the fourth protective adhesive 170, the winding end of the first current collector 121 is attached to the outermost ring of the cell body 110, which improves the integrity of the cell body 110, helps to improve the winding tightness, and thus improves the energy density of the battery.

[0097] According to some embodiments of this utility model, the projection of the empty foil area 123 in the reference plane is spaced apart from the projection of the end of the fourth protective adhesive 170 near the first bending area 111 of the cell body 110 in the reference plane, and the empty foil area 123 is located on the side of the fourth protective adhesive 170 near the first bending area 111 that is away from the second bending area 112. This ensures that the fourth protective adhesive 170 and the empty foil area 123 do not overlap in the second direction, thereby increasing the flatness of the cell body 110 in the second direction and improving the energy density of the cell body 110.

[0098] Secondly, embodiments of the present invention provide a battery, comprising: an outer casing and the aforementioned battery cell 100, wherein the outer casing covers the battery cell 100.

[0099] The battery of this invention, due to the use of the aforementioned cell 100, has higher energy density and longer battery life. During charging, the current path is shorter, the current distribution is more uniform, and the charging speed is faster.

[0100] The battery manufacturing steps of this invention may include:

[0101] S1: Prepare the first active material slurry, coat the first active material slurry on the surface of the first current collector 121 to form the first active layer 122, and obtain the first electrode 120 by baking, rolling and cutting.

[0102] Optionally, the preparation method of the first active material slurry is as follows: after the conductive agent and PVDF adhesive are mixed evenly, lithium cobalt oxide is added and stirred evenly to obtain the first active material slurry.

[0103] Optionally, the first active layer 122 may include one or more of lithium cobalt oxide, lithium iron phosphate, lithium nickel cobalt manganese, lithium nickel cobalt aluminum, lithium manganese oxide, and lithium-rich manganese-based lithium. For example, the first active layer 122 may be composed of 97.6% by weight of lithium cobalt oxide, 1.05% by weight of PVDF, and 1.35% by weight of a conductive agent. The conductive agent may include at least one of conductive carbon black, Ketjen black, single-walled carbon nanotubes, and multi-walled carbon nanotubes.

[0104] Optionally, the first active layer 122 further includes a first adhesive, which may be a polyvinylidene fluoride (PVDF) adhesive.

[0105] S2: Prepare a second active material slurry, coat the second active material slurry onto the second current collector 131 to form a second active layer 132, and obtain a second electrode 130 by baking, rolling and cutting.

[0106] The preparation method of the second active material slurry is as follows: 0.5% by weight of conductive agent and 97% by weight of graphite powder are mixed evenly, deionized water is added, and then 1.3% by weight of carboxymethyl cellulose and 1.2% by weight of styrene-butadiene rubber adhesive are added and stirred evenly to obtain the second active material slurry.

[0107] Optionally, the second active layer 132 may be one or more of the following: natural graphite, artificial graphite, mesophase carbon microspheres, lithium titanate, silicon anode, silicon-carbon anode, and alloy anode.

[0108] Optionally, the second active layer 132 further includes a second adhesive, which may be styrene-butadiene rubber.

[0109] S3: The first electrode 120, the diaphragm, and the second electrode 130 are stacked and wound together, and connected to the first electrode adapter and the second electrode adapter to form the battery cell body.

[0110] S4: The aluminum-plastic film is die-cut to obtain the outer film shell.

[0111] The thickness of the aluminum-plastic film shell is 50-200μm.

[0112] S5: The battery cell is installed into the outer casing, and then undergoes encapsulation, baking, electrolyte injection, formation, sorting, secondary sealing, OCV and packaging to obtain the battery.

[0113] S6: Perform a cycle test on the battery.

[0114] During the cycle test, carefully observe the appearance of the battery, such as peeling of the aluminum-plastic film on the side or damage to the four corners.

[0115] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "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 are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 utility model.

[0116] In the description of this utility model, "first feature" and "second feature" may include one or more of the features.

[0117] In the description of this utility model, "multiple" means two or more.

[0118] In the description of this utility model, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0119] In the description of this utility model, the terms "above", "over" and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0120] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. 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.

[0121] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell (100), characterized in that, include: The battery cell body (110) includes a first electrode (120), a second electrode (130), and a separator (140). The first electrode (120) and the second electrode (130) have opposite polarities. The first electrode (120), the separator (140), and the second electrode (130) are stacked and then wound to form the battery cell body (110). The first electrode (120) includes a first current collector (121) and a first active layer (122) coated on the surface of the first current collector (121). The first current collector (121) has an empty foil area (123) that is not coated with the first active layer (122). The second electrode (130) includes a second current collector (131) and a second active layer (132) coated on the surface of the second current collector (131). The second current collector (131) has a plurality of second soft tabs (133). A first electrode adapter (150) and a second electrode adapter (160), wherein the first electrode adapter (150) is connected to the empty foil area (123) and the second electrode adapter (160) is connected to the second soft electrode tab (133); Multiple second soft tabs (133) are stacked along a second direction to form a second tab, the second tab is connected to the second electrode, and the first electrode adapter (150) is connected to the empty foil area (123).

2. The battery cell (100) according to claim 1, characterized in that, The battery cell body (110) includes a first bending region (111) and a second bending region (112) formed by winding, the first bending region (111) and the second bending region (112) being opposite to each other along a first direction. The second current collector (131) includes a first single-sided coated section (1311) and a first double-sided coated section (1312) connected sequentially in a winding order. The second active layer (132) includes a second outer active layer (1321) and a second inner active layer (1322). The outer sides of both the first single-sided coated section (1311) and the first double-sided coated section (1312) are coated with the second outer active layer (1321), and the inner side of the first double-sided coated section (1312) is coated with the second inner active layer (1322). The end of the first single-sided coated section (1311) away from the first double-sided coated section (1312) constitutes the winding start end of the second current collector (131). The winding start end of the second current collector (131) is located between the first bending area (111) and the second bending area (112). The second outer active layer (1321) extends beyond the first bending area (111) in the winding direction. The first single-sided coated section (1311) has at least one second soft tab (133).

3. The battery cell (100) according to claim 1, characterized in that, The first single-sided coated section (1311) of the second current collector (131) includes a first bent portion (1311a) and a second bent portion (1311b) formed by sequential winding. The first bent portion (1311a) is located in the first bent region (111) of the cell body (110), and the second bent portion (1311b) is located in the second bent region (112) of the cell body (110). The starting point of the second outer active layer (1321) of the second current collector (131) extends beyond the first bend (1311a), and the distance A1 between the starting point of the second outer active layer (1321) and the center of the first bend (1311a) along the first direction satisfies: A1 > 0 mm.

4. The battery cell (100) according to claim 2, characterized in that, The first single-sided coated section (1311) has at least one second soft tab (133) in the region between the first bent portion (1311a) and the second bent portion (1311b), and / or, The width W1 of the second soft electrode tab (133) along the first direction and the width W2 of the second electrode adapter (160) along the first direction satisfy the following condition: W1 / W2≥1.

1.

5. The battery cell (100) according to claim 3, characterized in that, The first double-sided coated section (1312) includes a third bent portion (1312a) formed on the outside of the first bent portion (1311a). The starting point of the second inner active layer (1322) extends beyond the third bend (1312a), and the distance A2 between the center of the third bend (1312a) and the starting point of the second inner active layer (1322) satisfies: A2 > 0 mm.

6. The battery cell (100) according to claim 3, characterized in that, The projection of the starting point of the second outer active layer (1321) onto the reference plane is spaced apart from the projection of the starting end of the first electrode (120) onto the reference plane, and the starting end of the first electrode (120) is located on the side of the starting point of the second outer active layer (1321) facing the second bending region (112). The first direction and the third direction together define the reference plane.

7. The battery cell (100) according to claim 6, characterized in that, The projection of the winding start end of the second current collector (131) in the reference plane is spaced apart from the projection of the empty foil area (123) in the reference plane, and the empty foil area (123) is located on the side of the empty foil area (123) of the second current collector (131) facing the second bending area (112).

8. The battery cell (100) according to claim 1, characterized in that, The surface of the second active layer (132) is provided with a groove (135), the width A3 of which satisfies: 0.01mm ≤ A3 ≤ 0.2mm, and / or, The spacing A4 between two adjacent grooves (135) along the first direction satisfies: 0.5mm ≤ A4 ≤ 2mm, and / or, The distance A5 between the end of the groove (135) along the third direction and the edge of the second active layer (132) along the third direction satisfies: 0.05mm ≤ A5 ≤ 3mm, and / or, The spacing A6 between the groove (135) closest to the edge of the second active layer (132) along the first direction and the edge of the second active layer (132) along the first direction satisfies: 0.05mm ≤ A6 ≤ 3mm, and / or, The first active layer (122) is provided with a plurality of grooves (124) spaced apart along the first direction. The plurality of grooves (124) are respectively located in the first bending area (111) and the second bending area (112). The depth D1 of the grooves (124) along the second direction satisfies: 5μm≤D1≤100μm.

9. The battery cell (100) according to claim 1, characterized in that, The empty foil region (123) has the second soft tab (133) on both sides along the second direction.

10. The battery cell (100) according to claim 1, characterized in that, The first electrode (120) includes a first edge region (120a) and a first main body region (120b), wherein the thickness difference between the first edge region (120a) and the first main body region (120b) does not exceed 15 μm, and / or, The second electrode (130) includes a second edge region (130a) and a second main body region (130b), and the thickness difference between the second edge region (130a) and the second main body region (130b) does not exceed 20 μm.

11. The battery cell (100) according to claim 1, characterized in that, The first current collector (121) includes a second single-sided coating section (1211) and a second double-sided coating section (1212). The second single-sided coating section (1211) has the first active layer (122) coated on one side of its surface facing the inside of the cell body (110), and the second double-sided coating section (1212) has the first active layer (122) coated on both sides. The first active layer (122) on the second single-sided coating section (1211) is coated with a safety layer, the thickness of which is 1-20 μm.

12. The battery cell (100) according to claim 11, characterized in that, The material of the security layer includes at least one of SiO2, PPA, or PVDF.

13. The battery cell (100) according to claim 1, characterized in that, The first electrode adapter (150) includes a first solder mark formed by welding to the empty foil area (123), and the first electrode (120) is provided with a first protective adhesive (125), the first protective adhesive (125) at least covering the first solder mark, and / or, The second electrode adapter (160) includes a second solder mark (161) formed by welding with the second electrode tab, and the second electrode adapter (160) is provided with a second protective adhesive (162), which covers the second solder mark (161).

14. The battery cell (100) according to claim 13, characterized in that, The first protective adhesive (125) extends beyond the edge of the first electrode (120) in a third direction, and the second protective adhesive (162) extends in the first direction, with the first protective adhesive (125) and the second protective adhesive (162) partially overlapping.

15. The battery cell (100) according to claim 13, characterized in that, A third protective adhesive (136) is provided on the second electrode (130). The third protective adhesive (136) is opposite to the first protective adhesive (125) along the first direction. The third protective adhesive (136) separates the first electrode (120) and the second electrode (130). The third protective adhesive (136) is spaced apart from the second soft electrode tab (133).

16. The battery cell (100) according to claim 11, characterized in that, It also includes a fourth protective adhesive (170), which is applied to the outer surface of the cell body (110) and covers the end of the second single-sided coating section (1211) of the first current collector (121) that is away from the second double-sided coating section (1212).

17. The battery cell (100) according to claim 16, characterized in that, The projection of the empty foil area (123) in the reference plane is spaced apart from the projection of the fourth protective adhesive (170) near the first bending area (111) of the cell body (110) in the reference plane, and the empty foil area (123) is located on the side of the fourth protective adhesive (170) away from the second bending area (112) near the first bending area (111).

18. A battery, characterized in that, include: Outer membrane shell; The battery cell (100) according to any one of claims 1-17, wherein the outer membrane shell covers the battery cell (100).

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