Battery cell and battery

Abstract

The utility model relates to the technical field of battery energy, in particular to a battery cell and a battery. The battery cell comprises a battery cell body and at least three tab assemblies, the tab assembly is positioned at the end part of the battery cell body, comprises a plurality of tabs which are arranged in a stacked manner, and is provided with an overcurrent area; the size of the tab in the length direction of the pole piece is less than or equal to 45mm; the total area S of the overcurrent areas of all the tab assemblies meets the condition that S is greater than or equal to I / (K * F); wherein I is the maximum current threshold value allowed to pass through in the overcurrent region, K is the current-carrying capacity per unit area in the overcurrent region, and F is a correction coefficient; k is greater than or equal to 5A / mm < 2 > and less than or equal to 10A / mm < 2 >, I is greater than or equal to twice of the standard capacity of the battery, and the value range of F is 0.5-0.9. According to the battery cell provided by the invention, the tabs are not easy to fold, and after the battery cell is arranged in the battery, the over-current capability of the battery can be met, and the temperature rise of the battery in the charging and discharging process is reduced.

Description

Technical Field

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

[0002] Lithium-ion batteries have become the main power source for energy storage and electric vehicles due to their many advantages. With the growing demand of people, lithium-ion batteries are gradually developing towards fast charging, long life, high energy density and high safety. At present, some cells and batteries include at least one cell. The capacity of cells and batteries can be increased by increasing the size of cells and batteries. However, as the size and capacity of the battery increase, the temperature rise of the battery during the charging and discharging process also increases. In order to solve the problem of battery temperature rise, it is necessary to increase the flow area of ​​the current collector of the electrode in the cell.

[0003] At present, in order to improve the energy density of the battery, the thickness of the current collector in the electrode is relatively thin. Generally, the battery's current capacity is met by increasing the size of the electrode tab on the current collector in the length direction of the electrode to reduce the temperature rise of the battery during charging and discharging.

[0004] However, as the size of the pole tab increases in the length direction of the pole piece, the pole tab is prone to folding during the production of the battery cell, affecting the subsequent processing of the battery cell and the performance of the battery. Utility Model Content

[0005] Based on this, the present application provides a battery cell and a battery to solve the problem in the related art that after the capacity of the battery is increased, it is not possible to simultaneously improve the folding of the tabs and reduce the temperature rise of the battery during the charging and discharging process.

[0006] In one aspect, the present application provides a battery cell, comprising a battery cell body and at least three tab assemblies;

[0007] The tab assembly is located at the end of the battery body, and the tab assembly includes a plurality of tabs stacked in layers, and the tab assembly has a current flow area;

[0008] The dimension of the pole lug in the length direction of the pole piece is less than or equal to 45 mm;

[0009] The total area S of the flow area of ​​all tab components satisfies: S ≥ I / (K×F);

[0010] Where I is the maximum current threshold allowed to pass through the overcurrent area, K is the current carrying capacity per unit area in the overcurrent area, and F is the correction factor; 5A / mm 2 ≤K≤10A / mm 2 , I is greater than or equal to twice the standard capacity of the battery, and the value range of F is 0.5-0.9.

[0011] In a possible implementation, the dimension of the pole ear in the length direction of the pole piece is greater than or equal to 20 mm.

[0012] In a possible implementation, the ratio between the size of the pole tab in the length direction of the pole piece and the size of the pole tab in the width direction of the pole piece is in the range of 1 / 3-1 / 2.

[0013] In a possible implementation, the electrode tab includes a coating region and an empty current collector region, and the empty current collector region is located at one end of the coating region away from the battery cell body.

[0014] In a possible implementation, the dimension of the coating area in the width direction of the pole piece is less than or equal to 2 mm.

[0015] In a possible implementation, a transition fillet is provided between the side of the pole ear in the length direction of the pole piece and the edge of the battery cell body.

[0016] In a possible implementation, the central angle corresponding to the transition fillet is in the range of 78°-85°.

[0017] In one possible implementation, the tab assembly also has a misalignment area, and the distance between the tab assembly and the edge of the battery cell is greater than or equal to D+A+5mm, where D is the thickness of the battery cell and A is the size of the misalignment area in the length direction of the pole piece.

[0018] In a possible implementation, at least three tab assemblies are divided into a positive tab assembly and a negative tab assembly, and a distance between a positive tab assembly and an adjacent negative tab assembly is greater than or equal to A+3 mm.

[0019] In a possible implementation, the battery cell further includes two adapter plates, part of the pole lug assembly is welded to one of the adapter plates, and the remaining pole lug assembly is welded to the other adapter plate, a welding area is provided between the pole lug assembly and the corresponding adapter plate, and the current flow area is located within the welding area.

[0020] In a possible implementation, the tab assembly is ultrasonically welded to the corresponding adapter sheet, and a ratio of the flow area to the welding area is greater than or equal to 50%.

[0021] In a possible implementation, the pole tab assembly and the corresponding adapter are laser welded, and the welding depth between the pole tab assembly and the corresponding adapter is greater than or equal to 0.5 mm and less than or equal to 1 mm.

[0022] In a possible implementation, a protective adhesive layer is provided on a side of the tab assembly facing away from the adapter sheet and a side of the adapter sheet facing away from the tab assembly.

[0023] On the other hand, the present application also provides a battery, comprising at least one of the above-mentioned battery cells.

[0024] The battery cell and battery provided in the present application include a battery cell body and at least three pole ear assemblies. The pole ear assembly includes a plurality of pole ears arranged in a stacked manner, and the size of the pole ears in the length direction of the pole piece is less than or equal to 45 mm. During the production process of the battery cell, each pole ear is not easy to be folded. The number of pole ear assemblies is at least three, and the total area S of the flow area of ​​each pole ear assembly satisfies: S≥I / (K×F). Compared with the battery cell in the related art that is only provided with two pole ear assemblies, namely, a positive pole ear assembly and a negative pole ear assembly, by increasing the number of pole ear assemblies, the flow area of ​​the collector can be guaranteed, thereby ensuring the flow capacity of the battery cell and reducing the temperature rise of the battery. In this way, the pole ears of the battery cell provided in the present application are not easy to be folded. After the battery cell is set in the battery, it can meet the flow capacity of the battery and reduce the temperature rise of the battery during charging and discharging. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the connection between the tab assembly and the battery cell body provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of the distance between the positive electrode tab assembly and the negative electrode tab assembly provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of a pole piece at a pole ear position provided in an embodiment of the present application;

[0030] Figure 5 Schematic diagram of the connection between the tab assembly and the adapter provided in the embodiment of the present application Figure 1 ;

[0031] Figure 6 Schematic diagram of the connection between the tab assembly and the adapter provided in the embodiment of the present application Figure 2 .

[0032] Description of reference numerals:

[0033] 100-battery cell body;

[0034] 200-ear assembly; 210-positive ear assembly; 220-negative ear assembly; 230-ear; 231-coating area; 232-empty current collector area; 233-transition fillet; 240-dislocation area; 250-welding area;

[0035] 300-adapter;

[0036] 400- positive electrode;

[0037] 500-Negative electrode. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] The terms "first", "second" and "third" (if any) in the specification and claims of this application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0042] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or display comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or display.

[0043] In the prior art, a battery cell includes a battery cell body and a positive ear assembly and a negative ear assembly located at the end of the battery cell body. Among them, the positive ear assembly includes a plurality of stacked positive ears, and the negative ear assembly includes a plurality of stacked negative ears. In batteries with larger capacity, in order to solve the problem of temperature rise of the battery, the size of the positive ear and / or the negative ear in the length direction of the corresponding pole piece is set larger. However, when the size of the ear in the length direction of the pole piece is large, the ear on the pole piece of the battery cell is prone to uneven force and folding during the die-cutting, rolling and winding process. After the ear is folded, its internal resistance increases, which can easily lead to thermal runaway of the battery. In addition, the folded ear will also affect the subsequent production and processing of the battery cell.

[0044] After repeated thinking and verification, the inventors found that by controlling the size of a single pole ear in the length direction of the pole piece so that the size of each pole ear in the length direction of the pole piece does not exceed 45mm, the folding of the pole ear during the production of the battery cell can be reduced. By increasing the number of pole ear assemblies and ensuring that the total area of ​​the flow area on each pole ear assembly satisfies S≥I / (K×F), the flow area of ​​the collector can be guaranteed, thereby ensuring the flow capacity of the battery cell and reducing the temperature rise of the battery. In this way, when the battery capacity is large, the temperature rise of the battery is reduced, and the pole ear is not easy to fold, ensuring the performance of the battery.

[0045] In view of this, the inventors have designed a battery cell and a battery, wherein the battery cell is provided with at least three tab assemblies, each tab assembly comprising a plurality of tabs arranged in a stacked manner. The dimension of each tab in the length direction of the pole piece does not exceed 45 mm, and at the same time, the total area of ​​the flow area on each tab assembly satisfies S≥I / (K×F). The dimension of the tab in the length direction of the pole piece is small, and the tab is not easy to be folded during the production process of the battery cell. At the same time, the flow area of ​​the current collector is guaranteed, and the temperature rise of the battery during the charging and discharging process is reduced.

[0046] The following is a detailed description of the technical solution of the battery cell and battery provided in the embodiment of the present application in conjunction with the accompanying drawings. It is worth mentioning that the length direction of the pole piece is Figure 1-Figure 6 The direction of the X axis; the width direction of the pole piece Figure 1-Figure 6 The direction of the Y axis; Figure 1-Figure 6 The direction indicated by the Z axis is the thickness direction of the battery cell.

[0047] Reference Figures 1 to 3As shown, the battery cell provided in the embodiment of the present application includes a battery cell body 100 and at least three pole lug assemblies 200. The pole lug assembly 200 is located at the end of the battery cell body 100, and the pole lug assembly 200 includes a plurality of pole lugs 230 arranged in a stacked manner, and the pole lug assembly 200 has a flow area. The dimension of the pole lug 230 in the length direction of the pole piece is less than or equal to 45 mm. The total area S of the flow area of ​​all pole lug assemblies 200 satisfies: S ≥ I / (K × F). Among them, I is the maximum current threshold allowed to pass through the flow area, K is the current carrying capacity per unit area in the flow area, and F is the correction factor. 5A / mm 2 ≤K≤10A / mm 2 , I is greater than or equal to twice the standard capacity of the battery, and the value range of F is 0.5-0.9.

[0048] Among them, the battery cell provided in this embodiment can be a winding core formed by winding a positive electrode sheet and a negative electrode sheet, or it can be a stacked core formed by staggered stacking of multiple positive electrode sheets and multiple negative electrode sheets, which is not limited here. The dimensions of the pole ears 230 of different pole ear assemblies 200 in the length direction of the corresponding pole sheets can be the same or different, which is not limited here. It can be understood that a diaphragm is arranged between the positive electrode sheet and the negative electrode sheet. Exemplarily, the diaphragm includes a substrate and a ceramic layer, the ceramic layer can be arranged on the substrate through an adhesive layer, and the ceramic layer of the diaphragm is arranged opposite to the positive electrode sheet.

[0049] Schematically, the plurality of tab assemblies 200 are divided into a positive tab assembly 210 and a negative tab assembly 220. The positive tab assembly 210 includes a plurality of stacked positive tabs, and the negative tab assembly 220 includes a plurality of stacked negative tabs. It is understood that the number of tab assemblies 200 of at least one polarity is at least two. The specific number of the positive tab assemblies 210 and the specific number of the negative tab assemblies 220 are not limited in this embodiment. Those skilled in the art can set them according to actual needs. For example, Figure 1 As shown, the battery cell may include two positive tab assemblies 210 and two negative tab assemblies 220. It should be noted that, for the actual production efficiency and manufacturing considerations of the battery cell, the fewer the number of tab assemblies 200, the more conducive to production, provided that the flow area is met. It is worth mentioning that the flow area is the area on the tab assembly 200 that is electrically connected to the outside.

[0050] For example, the battery cell is provided with two negative electrode ear assemblies 220, the sum of the dimensions of the two negative electrode ear assemblies 220 in the length direction of the negative electrode sheet is required to be ≥65 mm, and the dimensions of each negative electrode ear assembly 220 in the length direction of the negative electrode sheet can be 35 mm respectively.

[0051] In one possible implementation, Figure 1As shown, the positive tab assembly 210 and the negative tab assembly 220 may be located at the same end of the battery cell body 100 ; in another possible implementation, the positive tab assembly 210 and the negative tab assembly 220 may be located at opposite ends of the battery cell body 100 , respectively.

[0052] In this embodiment, I≥2C (C is the standard capacity of the battery, which is optional. The capacity range of the battery is 630Ah-1Ah); the specific size of F is related to the actual use temperature of the battery. Through orthogonal experimental verification (the battery operating temperature range is -20°C to 50°C), it can be obtained that the value range of F is 0.5-0.9; in order to meet the battery overcurrent requirements and manufacturing requirements at the same time, the range of S can be: 683.3mm 2 ≤S≤820mm 2 .

[0053] The battery cell provided in this embodiment includes a battery cell body 100 and at least three tab assemblies 200. The tab assembly 200 includes a plurality of tabs 230 stacked in layers, and the size of the tab 230 in the length direction of the pole piece is less than or equal to 45 mm. During the production process of the battery cell, each tab 230 is not easy to be folded. The number of tab assemblies 200 is at least three, and the total area S of the flow area of ​​each tab assembly 200 satisfies: S ≥ I / (K×F). Compared with the battery cell in the related art that is only provided with two tab assemblies 200, namely, a positive tab assembly 210 and a negative tab assembly 220, by increasing the number of tab assemblies 200, the flow area of ​​the collector can be guaranteed, thereby ensuring the flow capacity of the battery cell and reducing the temperature rise of the battery. In this way, the tab 230 of the battery cell provided in the present application is not easy to be folded. After the battery cell is set in the battery, it can meet the flow capacity of the battery and reduce the temperature rise of the battery during charging and discharging.

[0054] In a specific embodiment, the dimension of the pole ear 230 in the length direction of the pole piece is greater than or equal to 20 mm. For example, the dimension of the pole ear 230 in the length direction of the pole piece can be 20 mm, 25 mm, 30 mm, 35 mm or 40 mm. It can be understood that the battery cell includes a positive electrode sheet and a negative electrode sheet that are stacked, and the pole ear 230 can be formed at the end of the corresponding pole sheet by die cutting. When the dimension of the pole ear 230 in the length direction of the pole sheet is less than 20 mm, in order to ensure the flow area of ​​the current collector, the number of pole ears 230 is large, and then the number of die-cutting of the pole sheet is large, which affects the production efficiency of the pole sheet and the battery cell.

[0055] With this structure, the pole ear 230 is not prone to folding during the production of the battery cell, and the number of die-cutting of the pole piece can be reduced, thereby ensuring the production efficiency of the pole piece and the battery cell.

[0056] Schematically, the ratio between the dimension of the pole tab 230 in the pole piece length direction and the dimension of the pole tab 230 in the pole piece width direction is in the range of 1 / 3-1 / 2.

[0057] Among them, the pole piece can be verified by DOE (Design of Experiments) data. Through DOE data, it can be obtained that when the ratio between the size of the pole piece 230 in the pole piece length direction and the size in the pole piece width direction is less than 1 / 3 or greater than 1 / 2, the pole piece 230 is prone to bend during the production of the battery cell. In other words, the above setting can further prevent the pole piece 230 from being folded during the production of the battery cell.

[0058] In one embodiment, Figure 4 As shown, the tab 230 includes a coating region 231 and an empty current collector region 232 . The empty current collector region 232 is located at one end of the coating region 231 away from the battery cell body 100 .

[0059] Schematically, when the tab 230 is die-cut, the root of the die-cut extends to the area on the pole piece where the coating is provided, so that the root of the tab 230 is provided with a coating, that is, the coated tab 230. Specifically, when the positive tab 230 is die-cut, the root of the die-cut is not allowed to be located on the positive current collector aluminum foil, and when the negative tab 230 is die-cut, the root of the die-cut is not allowed to be located on the negative current collector copper foil. It can be understood that the area on the tab 230 where the coating is provided is the coating area 231, and the area where the coating is not provided is the empty current collector area 232.

[0060] It is worth mentioning that when the two opposite sides of the pole ear 230 are coated, the offset distance between the coatings on both sides of the pole ear 230 in the width direction of the pole piece does not exceed 0.5mm, which facilitates the smooth implementation of the subsequent die-cutting process during the production of the battery cell.

[0061] With this structure, the coating area 231 can increase the structural strength of the root of the pole ear 230, and the pole ear 230 is not easy to be folded during the process of die cutting, rolling and winding of the pole piece.

[0062] In a specific embodiment, please continue to refer to Figure 4 , the dimension d2 of the coating area 231 in the width direction of the pole piece is less than or equal to 2 mm. Exemplarily, d2 can be equal to 0.5 mm, 1 mm, 1.5 mm or 2 mm, etc. When d2 is greater than 2 mm, the dimension of the empty collector area 232 in the width direction of the pole piece may be smaller, which may affect the subsequent die-cutting process during the production of the battery cell. Alternatively, when d2 is greater than 2 mm, the length of the root of the die-cutting extending to the area on the pole piece where the coating is provided is longer, affecting the capacity of the battery cell.

[0063] This structure can ensure the capacity of the battery cell while ensuring the structural strength of the root of the tab 230 , and can also ensure smooth subsequent die-cutting processes during the production of the battery cell.

[0064] Indicatively, Figure 4 As shown, a transition fillet 233 is provided between the side of the pole ear 230 in the length direction of the pole piece and the edge of the battery cell body 100 .

[0065] In a possible implementation, transition fillets 233 are respectively provided between two opposite sides of the pole tab 230 in the length direction of the pole piece and the edge of the battery cell body 100, and the two transition fillets 233 are symmetrically arranged. It can be understood that the size of the pole tab 230 in the length direction of the pole piece gradually increases from the end away from the battery cell body 100 to the end close to the battery cell body 100. By providing the transition fillet 233, the structural strength of the root of the pole tab 230 can be improved, and the pole tab 230 is not easy to be folded during the die cutting, rolling and winding of the pole piece.

[0066] In a specific embodiment, Figure 4 As shown, the central angle α corresponding to the transition fillet 233 ranges from 78° to 85°.

[0067] Among them, DOE data verification can be performed for different sizes of α. Through DOE data, it can be obtained that when α<78° or α>85°, the tab 230 may also be folded during the production of the battery cell. In other words, when 78°≤α≤85°, the transition fillet 233 has the best effect on improving the structural strength of the root of the tab 230, and the tab 230 is not easy to be folded during the production of the battery cell.

[0068] In one possible implementation, Figure 2 As shown, the tab assembly 200 also has a misalignment region 240. The distance between the tab assembly 200 and the edge of the battery cell is greater than or equal to D+A+5 mm, where D is the thickness of the battery cell and A is the size of the misalignment region 240 in the length direction of the pole piece.

[0069] Among them, when multiple pole ears 230 are stacked, due to the manufacturing process capability deviation, there may be a deviation in the position between two adjacent pole ears 230 in the thickness direction of the battery cell. It can be understood that in the thickness direction of the battery cell, the area where the projections of multiple pole ears 230 of the battery cell assembly do not overlap is the misalignment area 240. In this embodiment, the distance between the pole ear assembly 200 and the edge of the battery cell is the distance between one end of the pole ear assembly 200 facing the edge of the battery cell and the edge of the battery cell. It can be understood that when the battery cell is a winding core, the portion of the pole piece located at the edge of the battery cell is arranged in an arc shape. The distance between the pole ear assembly 200 and the edge of the battery cell is greater than or equal to D+A+5mm. On the basis of considering the manufacturing process capability deviation, the pole ear 230 is prevented from being arc-shaped after the pole piece is wound into a battery cell.

[0070] Through the above arrangement, the pole ear 230 is prevented from bending, the flatness of the pole ear 230 is ensured, and the subsequent processing of the pole ear 230 is facilitated after the pole piece forms the battery cell.

[0071] like Figure 3 As shown, at least three tab assemblies 200 are divided into a positive tab assembly 200 and a negative tab assembly 200. A distance d1 between a positive tab assembly 200 and an adjacent negative tab assembly 200 is greater than or equal to A+3 mm.

[0072] For example, Figure 3 As shown in the figure, the positive ear assembly 210 is located on the right side of the negative ear assembly 220, and d1 is the distance between the left side of the positive ear assembly 210 and the right side of the negative ear assembly 220. It can be understood that when d1 is less than A+3mm, the distance between the positive ear assembly 210 and the negative ear assembly 220 is close, and the battery cell has a greater risk of short circuit. In this embodiment, d1≥A+3mm, on the basis of considering the manufacturing process capability deviation, the safety performance of the battery cell can be ensured to avoid the battery cell from short circuiting between the positive ear assembly 210 and the negative ear assembly 220.

[0073] It is worth mentioning that the positions of the plurality of tab assemblies 200 are staggered, that is, there is no overlapping area between two adjacent tab assemblies 200, which ensures that subsequent processes such as welding can proceed smoothly.

[0074] In one embodiment, Figure 5 and Figure 6 As shown, the battery cell also includes two adapter plates 300 , part of the tab assembly 200 is welded to one of the adapter plates 300 , and the remaining tab assembly 200 is welded to the other adapter plate 300 , a welding area 250 is provided between the tab assembly 200 and the corresponding adapter plate 300 , and the current flow area is located within the welding area 250 .

[0075] Among them, the two adapters 300 are respectively a positive adapter and a negative adapter, each positive ear assembly 210 is respectively welded and fixed to the positive adapter, and each negative ear assembly 220 is respectively welded and fixed to the negative adapter. It can be understood that the ear assembly 200 and the corresponding adapter 300 are fixed in the welding area 250, and the current flow area is the effective welding area between the ear assembly 200 and the corresponding adapter 300. The present embodiment does not limit the specific shape of the welding area 250, which can be circular, square or polygonal, etc., and is not the only limitation here. In a possible implementation, when the number of positive ear assemblies 210 and negative ear assemblies 220 is respectively multiple, multiple positive ear assemblies 210 are located on the same side of the positive adapter, and multiple negative ear assemblies 220 are located on the same side of the negative adapter.

[0076] Assuming the cell capacity is 650Ah, K = 6A / mm 2 , F = 0.85 as an example, the battery cell is provided with two positive tab assemblies 210 and two negative tab assemblies 220, and the area of ​​the current flow region on each tab assembly 200 is the same. Figure 5 As shown, when the shape of the welding area 250 can be a square, the shape of the flow area is the same as the shape of the welding area 250, and the length of the flow area on each tab assembly 200 can be 11.3 mm. Figure 6 As shown, when the shape of the welding area 250 is circular, the shape of the flow area is the same as the shape of the welding area 250, and the radius of the flow area on each tab assembly 200 can be 6.37 mm. When the shape of the flow area on the tab assembly 200 is other shapes such as ellipse or polygon, it can also be calculated according to the formula S≥I / (K×F).

[0077] With this structure, external devices can be connected to the two adapters 300 respectively. Since each tab assembly 200 is connected to the corresponding adapter 300 respectively, each tab assembly 200 can be connected to the outside through the two adapters 300 to realize charging and discharging of the battery cell.

[0078] In a possible implementation, the tab assembly 200 is ultrasonically welded to the corresponding adapter sheet 300 , and a ratio between the flow area and the welding area 250 is greater than or equal to 50%.

[0079] The flow area is the ultrasonic effective welding residual area. It can be understood that 100% welding area 250 ≥ ultrasonic effective welding residual area ≥ 50% welding area 250. For example, the ratio between the flow area and the welding area 250 can be 50%, 65%, 80% or 90%, etc., which is not limited here.

[0080] The above arrangement can ensure the stability of welding between the tab assembly 200 and the corresponding adapter sheet 300 and ensure the flow area of ​​the current collector.

[0081] In another possible implementation, the tab assembly 200 and the corresponding adapter plate 300 are laser welded, and the welding depth between the tab assembly 200 and the corresponding adapter plate 300 is greater than or equal to 0.5 mm and less than or equal to 1 mm.

[0082] Schematically, during the welding process of the tab assembly 200 and the corresponding adapter plate 300, the tab assembly 200 and the corresponding adapter plate 300 are first pressed tightly together, and a laser is used to hit the tab assembly 200 from the side of the tab assembly 200 facing away from the adapter plate 300 to weld and fix the tab assembly 200 on the adapter plate 300.

[0083] When the welding penetration between the tab assembly 200 and the corresponding adapter 300 is less than 0.5 mm, the reliability of welding between the tab assembly 200 and the corresponding adapter 300 is poor, and the tab assembly 200 is easy to fall off from the adapter 300. When the welding penetration between the tab assembly 200 and the corresponding adapter 300 is greater than 1 mm, the power of the laser is high, so that the welding cost between the tab assembly 200 and the adapter 300 is high.

[0084] In a possible implementation, a protective adhesive layer is provided on a side of the tab assembly 200 facing away from the adapter plate 300 and a side of the adapter plate 300 facing away from the tab assembly 200 .

[0085] For example, adhesive tape may be attached as protective adhesive layer on one side of the tab assembly 200 facing away from the adapter 300 and one side of the adapter 300 facing away from the tab assembly 200. The protective adhesive layer on the tab assembly 200 covers the weld marks on the tab assembly 200, and the protective adhesive layer on the adapter 300 covers the weld marks on the adapter 300.

[0086] This structure can prevent the welding marks on the tab assembly 200 or the adapter sheet 300 from contacting the battery cell body 100 and causing a short circuit by providing a protective adhesive layer.

[0087] The following briefly introduces the processing process of the battery cell so that those skilled in the art can better understand the technical solution of the present application. The battery cell described below is a winding core formed by winding a positive electrode sheet and a negative electrode sheet.

[0088] Pole sheet coating: The pole sheet coating method can be the same as the pole sheet coating method in the related art. For example, the positive pole sheet 400 and the negative pole sheet 500 are both coated continuously. The width of the positive current collector can be 35 mm, and the width of the positive active material layer on the positive current collector can be 518 mm ± 1 mm. The positive active material layer can be provided with insulating coatings on both sides opposite to each other in the width direction of the pole sheet. The width of each insulating coating can be 3.0 mm ± 0.5 mm. The coating weight of the positive active material layer on a single side of the positive current collector can be 0.0153 g / cm 2 ±0.00030g / cm 2 The misalignment distance of the positive electrode active material layers on both sides of the positive electrode current collector is less than 1 mm, and the sizes of the positive electrode active material layers and the insulating coating on both sides of the positive electrode current collector are consistent.

[0089] The width of the negative electrode current collector can be 35 mm, the width of the negative electrode active material layer on the negative electrode current collector can be 530 mm ± 1 mm, and the coating weight of the negative electrode active material layer on one side of the negative electrode current collector can be 0.0153 g / cm 2 ±0.00030g / cm 2 The misalignment distance of the negative electrode active material layers on both sides of the negative electrode current collector is less than 1 mm, and the sizes of the negative electrode active material layers and the insulating coating on both sides of the negative electrode current collector are consistent.

[0090] Pole sheet rolling: The thickness of the positive electrode sheet 400 after rolling can be 0.142 mm ± 0.003 mm, and the thickness of the negative electrode sheet 500 after rolling can be 0.097 mm ± 0.003 mm.

[0091] Pole sheet die-cutting: The positive electrode sheet 400 and the negative electrode sheet 500 are die-cut by laser respectively. After die-cutting, the length of the positive and negative electrode ears can be 35mm±1mm and the width can be 40mm±1mm.

[0092] Pole sheet cutting: using conventional cutting technology, the width of the positive electrode sheet 400 after cutting can be 259mm±0.5mm, and the width of the negative electrode sheet 500 can be 265mm±0.5mm.

[0093] Pole sheet winding: the number of folds of the positive electrode sheet 400 can be 130, the number of folds of the negative electrode sheet 500 can be 132, the thickness D of the battery cell can be 35 mm, the width H of the battery cell can be 568.3 mm, and multiple pole ears 230 are stacked to form a pole ear assembly 200, and the offset distance between the two pole ears 230 of the pole ear assembly 200 does not exceed 3 mm.

[0094] Among them, the thickness of the substrate of the separator in the battery cell can be 9μm, the thickness of the ceramic layer can be 2μm, and the thickness of the bonding layer can be 2μm. The length of the separator can be 148363mm±10mm, and the width of the separator can be 269mm±0.5mm. Both ends of the separator in the width direction of the electrode sheet exceed the negative electrode sheet 500, and the length of one end exceeding the negative electrode sheet 500 can be 2.5mm±0.5mm, and the length of the other end exceeding the negative electrode sheet 500 can be 1.5mm±0.5mm. Both ends of the negative electrode sheet 500 in the width direction of the electrode sheet exceed the positive electrode sheet 400, and the length of one end exceeding the positive electrode sheet 400 can be 2.5mm±0.5mm, and the length of the other end exceeding the positive electrode sheet 400 can be 1.5mm±0.5mm. In the length direction of the electrode sheet, both ends of the negative electrode sheet 500 extend beyond the positive electrode sheet 400. Taking the winding core as an example, the negative electrode sheet 500 at the head of the winding core may extend beyond the positive electrode sheet 400 by 0.5mm-2mm, and the negative electrode sheet 500 at the end of the winding core may extend beyond the positive electrode sheet 400 by 1.5mm-5mm.

[0095] Welding of the tabs 230: Welding each positive tab assembly 210 to the positive adapter, and welding each negative tab assembly 220 to the negative adapter. The subsequent cell production process is consistent with the cell production process in the related art.

[0096] The present application also provides a battery, comprising at least one of the above-mentioned battery cells.

[0097] Exemplarily, the battery further includes a shell, and the number of the battery cells may be two, and the two battery cells are respectively installed inside the shell and electrically connected to each other.

[0098] Illustratively, the battery may have a length of 280mm-585mm, a thickness of 60mm-80mm, a height of 240mm-290mm, a weight of 15KG-30KG, and a capacity of 630Ah-1400Ah. For example, the battery has a length of 583.5mm, a thickness of 80.5mm, a height of 290mm, a weight of 28KG, and a capacity of 1400Ah.

[0099] The battery provided in the present application has a larger capacity of the battery cell due to the use of the above-mentioned battery cell, and thus the battery has a larger capacity, and the tab 230 of the battery cell is not easy to fold. At the same time, the temperature rise of the battery during the charging and discharging process is relatively low, thereby ensuring the battery performance.

[0100] The battery provided in the present application has a large capacity. When it is used in energy storage equipment, such as energy storage containers, the number of batteries is smaller under the same container space volume, which reduces the amount of auxiliary materials such as cables in the energy storage equipment, reduces the cost of the energy storage equipment, and improves the space utilization of the energy storage equipment, so that the energy storage equipment can store more electricity, and improves the volume energy density and mass energy density of the entire energy storage equipment. In addition, the battery provided in the present application, due to the use of the above-mentioned battery cells, when the battery is used in the energy storage device, the number of battery cells can be reduced by 5-10 times, the number of series and parallel connections can be reduced by 5-10 times, the consistency of the series and parallel systems in the energy storage device can be improved, and the pressure difference problem can be improved.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: It includes a battery cell body and at least three tab assemblies; The tab assembly is connected to the battery body, the tab assembly includes a plurality of tabs stacked in layers, and the tab assembly has a current flow area; The dimension of the pole lug in the length direction of the pole piece is less than or equal to 45 mm; The total area S of the flow regions of all the tab assemblies satisfies: S≥I / (K×F); Where I is the maximum current threshold allowed to pass through the overcurrent area, K is the current carrying capacity per unit area in the overcurrent area, and F is the correction factor; 5A / mm 2 ≤K≤10A / mm 2 , I is greater than or equal to twice the standard capacity of the battery, and the value range of F is 0.5-0.

9.

2. The battery cell according to claim 1, characterized in that: The dimension of the pole lug in the length direction of the pole piece is greater than or equal to 20 mm.

3. The battery cell according to claim 1, characterized in that: The ratio of the dimension of the pole lug in the length direction of the pole piece to the dimension of the pole lug in the width direction of the pole piece is in the range of 1 / 3-1 / 2.

4. The battery cell according to claim 1, characterized in that: The pole tab comprises a coating area and an empty current collector area, wherein the empty current collector area is located at one end of the coating area away from the battery cell body.

5. The battery cell according to claim 4, characterized in that: The dimension of the coating area in the width direction of the pole piece is less than or equal to 2 mm.

6. The battery cell according to claim 1, characterized in that: A transition fillet is provided between the side of the pole ear in the length direction of the pole piece and the edge of the battery cell body.

7. The battery cell according to claim 6, characterized in that: The size range of the central angle corresponding to the transition fillet is 78°-85°.

8. The battery cell according to claim 1, characterized in that: The pole tab assembly also has a misaligned area, and the distance between the pole tab assembly and the edge of the battery cell is greater than or equal to D+A+5mm, wherein D is the thickness of the battery cell, and A is the size of the misaligned area in the length direction of the pole piece.

9. The battery cell according to claim 8, characterized in that: At least three of the tab assemblies are divided into a positive tab assembly and a negative tab assembly, and a distance between the positive tab assembly and an adjacent negative tab assembly is greater than or equal to A+3 mm.

10. The battery cell according to claim 1, characterized in that: The battery cell also includes two adapter plates, part of the tab assemblies are welded to one of the adapter plates, and the remaining tab assemblies are welded to the other of the adapter plates, a welding area is provided between the tab assemblies and the corresponding adapter plates, and the current flow area is located within the welding area.

11. The battery cell according to claim 10, characterized in that: The tab assembly is ultrasonically welded to the corresponding adapter sheet, and the ratio of the flow area to the welding area is greater than or equal to 50%.

12. The battery cell according to claim 10, characterized in that: The pole tab assembly and the corresponding adapter plate are laser welded, and the welding depth between the pole tab assembly and the corresponding adapter plate is greater than or equal to 0.5 mm and less than or equal to 1 mm.

13. The battery cell according to claim 10, characterized in that: A protective adhesive layer is provided on one side of the tab assembly facing away from the adapter sheet and on one side of the adapter sheet facing away from the tab assembly.

14. A battery, characterized in that: The invention comprises at least one battery cell according to any one of claims 1 to 13.

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