Battery and battery pack

Abstract

The present application relates to the technical field of batteries, and discloses a battery and a battery pack. The battery comprises: an electrode assembly, one side of which is provided with tabs; and a packaging film divided by a fold line into a first sub-packaging film and a second sub-packaging film, the first sub-packaging film and / or the second sub-packaging film extending inwardly to form an accommodating recess for accommodating the electrode assembly, the second sub-packaging film being folded along the fold line and being opposite to and attached to the first sub-packaging film so as to cover the electrode assembly, and the peripheral sides of the first sub-packaging film and the second sub-packaging film being respectively provided with packaging regions surrounding the electrode assembly. In the present application, the fold line provides an accurate positioning reference for a folding action, effectively avoiding misalignment between the first sub-packaging film and the second sub-packaging film during folding, thereby improving the quality and reliability of hot-melt sealing. The packaging regions can completely overlap, so as to form a continuous and uniform sealing structure after hot melting, thereby significantly improving the safety of the battery and prolonging the service life of the battery.

Description

Batteries and battery packs Technical Field

[0001] This application relates to the field of battery technology, specifically to batteries and battery packs. Background Technology

[0002] Batteries typically refer to those encapsulated in an aluminum-plastic composite film casing. Batteries offer advantages such as high energy density, small size, light weight, low molding costs, and high safety.

[0003] A battery mainly consists of tabs, electrode assembly, and encapsulation film. The encapsulation film encapsulates the electrode assembly and tabs, and seals them through heat sealing. Specifically, a pit (single or double pit) is first punched in the encapsulation film, then the electrode assembly with the tabs welded on is placed into the pit, and finally the upper and lower encapsulation films are heat-sealed together.

[0004] However, during the process of bonding the existing encapsulation film to the electrode assembly, misalignment is prone to occur, resulting in misalignment of the encapsulation area, which affects the quality of subsequent hot melt sealing and may even cause sealing failure.

[0005] Therefore, how to optimize the folding encapsulation structure of the encapsulation film so that it can be accurately aligned during folding and bonding to ensure encapsulation quality is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, this application provides a battery and a battery pack to solve the problem that when the encapsulation film of the existing battery is folded and bonded to cover the electrode assembly, the encapsulation area is not aligned, which affects the quality of the heat-sealing and may even cause the seal to fail.

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

[0008] The pole assembly has a pole tab on one side;

[0009] The encapsulation film is divided into a first sub-encapsulation film and a second sub-encapsulation film by a fold line. The first sub-encapsulation film and / or the second sub-encapsulation film extend concavely to form a receiving groove for accommodating the electrode assembly. The second sub-encapsulation film is folded along the fold line and is opposite to and attached to the first sub-encapsulation film to cover the electrode assembly. The periphery of the first sub-encapsulation film and the second sub-encapsulation film are respectively provided with an encapsulation area surrounding the electrode assembly.

[0010] Beneficial Effects: This application divides the encapsulation film into a first sub-encapsulation film and a second sub-encapsulation film by a fold line, and forms a receiving groove for accommodating the electrode assembly on the first and / or second sub-encapsulation films. During assembly, the electrode assembly is first placed into the receiving groove, and then the second sub-encapsulation film is folded along the fold line to make it relatively adhered to the first sub-encapsulation film. The fold line provides a precise positioning reference for the folding action, effectively avoiding misalignment between the first and second sub-encapsulation films during the folding process, ensuring accurate alignment of the encapsulation area, thereby improving the quality and reliability of the heat-sealing. Because the alignment is accurate during folding and bonding, the encapsulation area can completely overlap, forming a continuous and uniform sealing structure after heat sealing, avoiding the risk of local sealing defects or leakage caused by misalignment, significantly improving the safety and service life of the battery. This folding encapsulation structure only requires setting a fold line and forming a receiving groove on the encapsulation film, without adding additional positioning parts, simplifying the battery manufacturing process, reducing production costs, and facilitating automated assembly.

[0011] In one alternative implementation,

[0012] The first sub-encapsulation film extends concavely to form the receiving groove for accommodating the electrode assembly;

[0013] The depth H1 of the receiving groove satisfies 0.1mm≤H1≤25mm;

[0014] The thickness H2 of the encapsulation film satisfies 0.05mm≤H2≤0.5mm and 0.02≤H2 / H1≤0.5.

[0015] Beneficial Effects: The battery of this application has a receiving groove formed by punching a pit in the first sub-encapsulation film. The electrode assembly with welded tabs is placed into the receiving groove of the first sub-encapsulation film. The second sub-encapsulation film is then folded along the fold line to bond the first and second sub-encapsulation films together, covering the electrode assembly inside. Finally, the encapsulation areas around the first and second sub-encapsulation films are heat-fused to form a sealed and fixed structure. The structure is simple and convenient to use. By limiting the relationship between the groove depth H1 of the receiving groove and the thickness H2 of the encapsulation film, as well as their ratio H2 / H1, it is possible to ensure that the encapsulation film has a suitable thickness, balancing puncture resistance and bending flexibility, avoiding cracking during battery expansion during charging and discharging. It also avoids the situation where the encapsulation film thickness is too small and the groove depth of the receiving groove is too large when punching a pit in the first sub-encapsulation film, causing the first sub-encapsulation film to be subjected to excessive shear force and fail. In addition, it ensures that the encapsulation film has a certain margin, avoiding the waste of encapsulation film material due to an excessively large encapsulation film thickness H2 and an excessively small groove depth H1, and also improves the space utilization rate of the battery.

[0016] In one optional embodiment, the bottom of the receiving groove is connected to the groove wall by a first arc, and the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm.

[0017] Beneficial effects: By limiting the radius of the first arc, stress concentration can be reduced, improving the battery's stability. If the radius of the first arc is too small, the first sub-encapsulation film will be subjected to greater shear force when dented, leading to its failure. If the radius of the first arc is too large, it will interfere with the edges of the electrode assembly, causing it to collapse and resulting in damage and a short circuit in the battery.

[0018] In an optional implementation, when 0.02≤H2 / H1<0.1, the radius R1 of the first arc satisfies 1mm≤R1≤5mm;

[0019] When 0.1≤H2 / H1≤0.5, the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm.

[0020] Beneficial effects: The radius of the first arc is set according to the ratio of the thickness of the encapsulation film to the depth of the receiving groove, which can further reduce stress concentration and improve the stability of the battery.

[0021] In one alternative embodiment, the wall of the receiving groove is inclined relative to the bottom of the groove, so that the area of ​​the groove opening is larger than the area of ​​the bottom of the groove.

[0022] Beneficial effects: By tilting the walls of the receiving groove and making the groove opening area larger than the bottom area, it is easier to install and limit the electrode assembly, reduce electrode assembly offset, and thus provide better support for the electrode assembly, ensuring that the encapsulation film can uniformly cover the electrode assembly and improve the encapsulation quality.

[0023] In one optional embodiment, the projected width H3 of the groove wall of the receiving groove in the height direction of the encapsulation film satisfies 0.1mm≤H3≤20mm and 0.2≤H3 / H1≤0.8.

[0024] Beneficial effects: By limiting the ratio between the depth of the receiving groove and the projected width of the groove wall along the height of the encapsulation film, the stability of the encapsulation film during the punching process can be ensured, and space utilization can be improved. If H3 / H1 is too small, the first sub-encapsulation film is prone to being subjected to large shear forces during punching, leading to its failure. If H3 / H1 is too large, H3 becomes too long, making it difficult for the groove wall to effectively support the electrode assembly, which is easily damaged. Furthermore, a large gap is formed between the groove wall and the electrode assembly, resulting in poor space utilization.

[0025] In one optional embodiment, the cross-section of the receiving groove is an inverted trapezoid, and the adjacent groove walls are connected by a second circular arc, wherein the radius R2 of the second circular arc satisfies 0.5mm≤R2≤5mm.

[0026] Beneficial effects: The inverted trapezoidal cross-section of the receiving groove, and the connection between adjacent groove walls via a second circular arc, reduces stress concentration. By limiting the radius of the second circular arc, the stability and space utilization of the encapsulation film during the punching process can be further improved. If the radius of the second circular arc is too small, the first sub-encapsulation film is prone to being subjected to large shear forces during punching, leading to its failure. If the radius of the second circular arc is too large, it will interfere with the edges of the electrode assembly, causing it to collapse and resulting in damage.

[0027] In one optional embodiment, the opening of the receiving groove is connected to the top surface of the encapsulation film via a third arc, wherein the radius R3 of the third arc satisfies 0.5mm≤R3≤5mm.

[0028] Beneficial effects: The groove opening of the receiving groove is connected to the top surface of the encapsulation film through the third arc, which can reduce stress concentration at the connection between the groove opening of the receiving groove and the encapsulation film, avoid damage to the encapsulation film, and facilitate the smooth bonding of the first sub-encapsulation film and the second sub-encapsulation film, thereby facilitating the encapsulation of the electrode assembly and improving the encapsulation quality.

[0029] In an optional implementation, when 0.02≤H2 / H1<0.1, the radius R3 of the third arc satisfies 1.5mm≤R3≤5mm;

[0030] When 0.1≤H2 / H1≤0.5, the radius R3 of the third arc satisfies 0.5mm≤R3≤5mm.

[0031] Beneficial effects: The radius of the third arc is set according to the ratio of the thickness of the encapsulation film to the depth of the receiving groove, which can further reduce stress concentration and improve the stability of the battery. If the radius of the third arc is too small, the first sub-encapsulation film is prone to being subjected to large shear forces when punching the first sub-encapsulation film, which may lead to the failure of the first sub-encapsulation film. If the radius of the third arc is too large, it will waste materials and space.

[0032] In one optional embodiment, the distance X between the edge of the receiving groove and the fold line satisfies 1mm+R3≤X≤30mm.

[0033] Beneficial effects: By limiting the dimensional range between the distance X between the edge of the receiving groove and the fold line and the radius of the third arc, the tensile stress on the encapsulation film during punching can be reduced, thus improving encapsulation quality. If the distance between the edge of the receiving groove and the fold line is too small, the first sub-encapsulation film is prone to cracking at the groove opening when the second sub-encapsulation film is folded, leading to encapsulation failure.

[0034] In one optional embodiment, the wall of the receiving groove is inclined at an obtuse angle relative to the bottom of the groove, and the depth of the receiving groove is H1;

[0035] In the width direction of the battery, the width W1 of the electrode group and the width W2 of the receiving groove satisfy 30mm≤W1≤200mm, 28mm≤W2≤250mm, and 0.8≤W1 / W2≤1.05;

[0036] Along the length of the battery, the length L1 of the electrode assembly and the length L2 of the receiving groove satisfy 50mm≤L1≤400mm, 45mm≤L2≤500mm, and 0.8≤L1 / L2≤1.1.

[0037] Beneficial effects: By defining the dimensions and proportional relationship between the electrode assembly and the receiving groove in the length and width directions of the battery, this application can provide suitable installation space for the electrode assembly and effectively fix it, avoiding interference between the electrode assembly and the receiving groove that could damage the electrode assembly, thus improving the installation reliability and yield of the battery. Furthermore, the groove wall is inclined at an obtuse angle relative to the bottom, facilitating smooth installation of the electrode assembly into the groove, reducing electrode assembly offset, and providing better support for the electrode assembly. It also ensures that the encapsulation film completely covers and tightly wraps the electrode assembly, improving the sealing effect. In addition, it optimizes the use of the encapsulation film and avoids material waste.

[0038] During assembly, the electrode assembly is first placed into the receiving groove, the encapsulation film is folded along the fold line, the first sub-encapsulation film and the second sub-encapsulation film are attached together, and the electrode assembly is wrapped in the receiving groove. Finally, the encapsulation areas around the first sub-encapsulation film and the second sub-encapsulation film are heat-fused to form a seal and fix it. The structure is simple and easy to use.

[0039] In one optional embodiment, the first sub-encapsulation film and the second sub-encapsulation film are respectively provided with a first rounded corner at opposite ends of the fold line, and the radius SR1 of the first rounded corner satisfies 1mm≤SR1≤50mm.

[0040] Beneficial effects: By creating first rounded corners at opposite ends of the fold line, rounded corners are formed after the encapsulation film is folded, preventing the corners of the encapsulation film from scratching operators, improving battery handling safety, and facilitating transportation. Furthermore, the first rounded corners effectively disperse stress, preventing the encapsulation film from cracking at the corners, thereby improving battery stability and encapsulation quality.

[0041] In one alternative embodiment, the width W3 of the encapsulation area in the width direction of the battery satisfies 1mm≤W3≤50mm.

[0042] Beneficial effects: By limiting the width of the encapsulation area to between 1mm and 50mm, it helps control the tension of the encapsulation film, preventing uneven stretching of the film during the encapsulation process due to an excessively wide or narrow encapsulation area, which would affect the encapsulation effect. It also ensures that the encapsulation film tightly covers the electrode assembly, preventing defects such as bubbles and wrinkles, thereby improving the battery encapsulation yield.

[0043] In one alternative embodiment, in the width direction of the battery, the distance L3 between the edge of the receiving groove and the edge of the first rounded corner satisfies W3+0.5mm≤L3≤50mm.

[0044] Beneficial effects: By limiting the distance between the edge of the receiving groove and the edge of the first rounded corner, sufficient space for heat fusion can be provided, avoiding insufficient heat fusion width leading to encapsulation failure. If the distance between the edge of the receiving groove and the edge of the first rounded corner is too small, the space for heat fusion encapsulation at the first rounded corner will be insufficient. After heat fusion, the melt width of the first rounded corner will be too small compared to other areas, posing a risk of leakage and leading to seal failure.

[0045] In an optional embodiment, when the thickness T of the battery is ≥ 20 mm, the first sub-encapsulation film and the second sub-encapsulation film extend concavely to form the receiving groove.

[0046] Beneficial effects: The first and second sub-encapsulation films extend concavely to form receiving grooves, creating a double-pit process. This facilitates even stress distribution on both sides during battery discharge cycle expansion, helping to offset the impact of expansion force on the encapsulation film tension, thereby reducing the risk of failure of the encapsulation film or heat-sealed edges. When the battery thickness T ≥ 20mm, a single-pit design results in a deeper receiving groove but a thinner surface. The plane of the sub-encapsulation film without receiving grooves is less prone to expansion and deformation, causing the expansion deformation force to concentrate on the sub-encapsulation film with receiving grooves. This makes the sub-encapsulation film with receiving grooves more susceptible to deformation and even cracking.

[0047] In an optional embodiment, when the receiving groove is formed by the recessed extension of the first sub-encapsulation film or the second sub-encapsulation film, the distance L4 between the side of the receiving groove near the fold line and the fold line and the depth H1 of the receiving groove satisfy 2mm≤L4≤30mm, 0.5mm≤H1≤50mm, and 0.2≤L4 / H1≤100.

[0048] Beneficial effects: The first or second sub-encapsulation film extends concavely to form a receiving groove. In the single-groove process, by limiting the distance between the side of the receiving groove near the fold line and the fold line, and the ratio of this distance to the depth of the receiving groove, the encapsulation quality of the battery can be improved. If the ratio of this distance to the depth of the receiving groove is too small, the fold of the encapsulation film will be too thin and easily deformed, with poor strength, and the encapsulation film will be easily damaged after folding. If the ratio of this distance to the depth of the receiving groove is too large, space and materials will be wasted.

[0049] In one optional embodiment, the encapsulation film is square-shaped and has a second rounded corner at each of the four corners, the radius of the second rounded corner SR2 satisfying 1mm≤SR2≤50mm.

[0050] Beneficial effects: By setting a second rounded corner at the four corners of the encapsulation film, it is possible to further prevent the corners of the encapsulation film from scratching operators, improve battery operation safety, and facilitate battery transportation.

[0051] In one optional embodiment, the distance L5 between the second fillet and the edge of the receiving groove satisfies 3mm≤L5≤50mm.

[0052] Beneficial effects: By limiting the distance between the second rounded corner and the edge of the receiving groove, a sufficiently wide packaging area can be provided, reducing the risk of packaging failure caused by excessively narrow hot melt width of the packaging area.

[0053] In one alternative embodiment, the first sub-encapsulation film and the second sub-encapsulation film respectively extend concavely to form the receiving groove for accommodating the electrode assembly;

[0054] The distance TL1 between the adjacent edges of the two receiving slots and the depth H1 of the receiving slots satisfy 0.6≤TL1 / H1≤100.

[0055] Beneficial Effects: The battery of this application forms receiving grooves by punching indentations on the first and second sub-encapsulation films. The electrode assembly, after welding the tabs, is placed into the receiving groove of the first sub-encapsulation film. The second sub-encapsulation film is then folded along the fold line, bringing the first and second sub-encapsulation films together and encapsulating the electrode assembly within the two receiving grooves. Finally, the encapsulation areas around the first and second sub-encapsulation films are heat-fused to form a sealed and fixed structure. The structure is simple and convenient to use. By limiting the ratio TL1 / H1 between the distance TL1 between adjacent edges of the two receiving grooves and the depth H1 of the receiving groove, a suitable receiving groove distance can be reserved when punching the receiving groove depth, improving the battery encapsulation quality and saving encapsulation film material. This avoids situations where the receiving groove is too deep and the distance between adjacent edges of the two receiving grooves is too small, leading to excessive stretching and deformation of the encapsulation film during the punching process, resulting in poor strength and cracking, causing battery seal failure.

[0056] In one optional embodiment, the distance TL1 between adjacent edges of the two receiving grooves satisfies 1mm≤TL1≤50mm, and the depth H1 of the receiving groove satisfies 0.5mm≤H1≤50mm.

[0057] Beneficial effects: By limiting the distance between adjacent edges of the two receiving slots, sufficient strength can be ensured when the encapsulation film is folded. During the denting process, the encapsulation film near the edge of the receiving slot is stretched and deformed, and stress exists. If the distance TL1 between adjacent edges of the two receiving slots is too small, the edge of the receiving slot is prone to cracking when the encapsulation film is folded, and the battery also has the risk of cracking and damage during subsequent use. By limiting the depth of the receiving slots, sufficient buffer space can be provided for the installation of the electrode assembly, preventing the electrode assembly from being deformed by pressure or the tabs from bending. It can also limit the movement of the electrode assembly within the receiving slots, avoiding short circuits in the battery due to vibration.

[0058] In one optional embodiment, the spacing TL2 between the side edges of the encapsulation film in the width direction and the side edges of the encapsulation film in the width direction satisfies 2.5mm≤TL2≤100mm and 5≤TL2 / H1≤50.

[0059] Beneficial effects: By limiting the spacing TL2 between the sides of the receiving groove in the width direction of the encapsulation film and the side of the encapsulation film in the width direction, a sufficiently wide encapsulation area can be reserved to heat-melt fix the first and second sub-encapsulation films. Further limiting the TL2 / H1 ratio ensures the encapsulation quality of the battery. If the TL2 / H1 ratio is too small, TL2 is insufficient, resulting in a narrow melt width after heat-melting shrinkage of the encapsulation area, making heat-melt sealing prone to failure. If the TL2 / H1 ratio is too large, TL2 is excessively large, wasting space and materials.

[0060] In one optional embodiment, the encapsulation film is square-shaped and has a first chamfer at each of the four corners. The dimension TL3 of the first chamfer in the length direction of the encapsulation film satisfies 1mm≤TL3≤50mm, and the dimension TW1 of the first chamfer in the width direction of the encapsulation film satisfies 1mm≤TW1≤50mm.

[0061] Beneficial effects: By adding a first chamfer at each of the four corners of the encapsulation film, it is possible to prevent the corners of the encapsulation film from scratching workers and to facilitate transportation. By limiting the dimensions of the first chamfer in the length and width directions of the encapsulation film, stress concentration can be effectively reduced, preventing the encapsulation film from tearing at the corners and improving the encapsulation quality of the battery.

[0062] In one optional embodiment, the cross-section of the receiving groove is an inverted trapezoid, and the connecting corners of the adjacent sidewalls of the receiving groove are respectively provided with a second chamfer corresponding to the first chamfer. The distance TL4 between the first chamfer and the second chamfer satisfies 2mm≤TL4≤100mm.

[0063] Beneficial effects: Setting the cross-section of the receiving groove to an inverted trapezoidal shape, and providing a second chamfer at the connecting corner of adjacent sidewalls of the receiving groove corresponding to the first chamfer, can reduce stress concentration at the receiving groove. Further limiting the distance TL4 between the first and second chamfers ensures the heat-fusion width of the encapsulation area, guaranteeing encapsulation quality. If the distance TL4 between the first and second chamfers is too small, the heat-fusion width of the encapsulation area will be narrow, easily leading to battery encapsulation failure; if the distance TL4 between the first and second chamfers is too large, it wastes encapsulation film material.

[0064] In one alternative embodiment, the second chamfer is a rounded corner, and the radius R of the rounded corner satisfies 0.4mm≤R≤6mm.

[0065] Beneficial effects: Setting the second chamfer as a rounded corner and limiting the radius range of the rounded corner can further improve the stability and space utilization of the encapsulation film during the punching process. If the radius R of the rounded corner is too small, the encapsulation film is prone to being subjected to large shear forces during punching, leading to film breakage and failure. If the radius R of the rounded corner is too large, the arc will interfere with the edge of the electrode assembly and crush the electrode assembly, causing damage to the electrode assembly and short circuit.

[0066] In one optional implementation, when 0.5mm≤H1<1mm, the radius R of the fillet satisfies 0.4mm≤R<1mm;

[0067] When 1mm≤H1<5mm, the radius R of the fillet satisfies 1mm≤R<3mm;

[0068] When 5mm≤H1≤50mm, the radius R of the fillet satisfies 3mm≤R≤6mm.

[0069] Beneficial effects: Setting the radius R of the arc to correspond with the depth H1 of the receiving groove can further improve the stability and space utilization of the encapsulation film during the punching process.

[0070] In one alternative embodiment, the encapsulation film has notches at opposite ends of the fold line.

[0071] Beneficial effects: By creating notches at opposite ends of the fold line, a chamfer can be formed after the encapsulation film is folded, preventing the corners of the encapsulation film from scratching workers and facilitating transportation.

[0072] In one alternative embodiment, the wall of the receiving groove is inclined relative to the bottom of the groove, and the inclination angle θ satisfies 95°≤θ≤160°.

[0073] Beneficial effects: By tilting the walls of the receiving groove, it facilitates smooth installation and positioning of the electrode assembly, reduces electrode assembly offset, and thus provides better support for the electrode assembly, ensuring that the encapsulation film can uniformly cover the electrode assembly and improve encapsulation quality. If the tilt angle θ is too small, the encapsulation film will be subjected to large shear forces during punching, and the heat-fused layer is prone to breakage and failure. If the tilt angle θ is too large, a large clearance space needs to be reserved to avoid interference between the groove wall and the electrode assembly, resulting in wasted space and materials.

[0074] Secondly, this application also provides a battery pack, including the aforementioned battery.

[0075] Beneficial effects: Since the battery pack includes a battery, it has the same effect as a battery, which will not be elaborated here. Attached Figure Description

[0076] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0077] Figure 1 is a partial structural schematic diagram of a battery according to an embodiment of this application;

[0078] Figure 2 is a schematic diagram of the structure of the encapsulation film of a battery according to an embodiment of this application before folding;

[0079] Figure 3 is a top view of Figure 2;

[0080] Figure 4 is a cross-sectional view of section AA in Figure 3;

[0081] Figure 5 is a partially enlarged schematic diagram of Figure 4;

[0082] Figure 6 is a schematic diagram of the structure of a battery according to an embodiment of this application;

[0083] Figure 7 is a top view of Figure 6;

[0084] Figure 8 is a cross-sectional view of section AA in Figure 7;

[0085] Figure 9 is a cross-sectional view of section BB in Figure 7;

[0086] Figure 10 is a schematic diagram of the structure of the encapsulation film of a battery according to an embodiment of this application before folding;

[0087] Figure 11 is a top view of Figure 10;

[0088] Figure 12 is a cross-sectional view at point CC in Figure 11;

[0089] Figure 13 is a schematic diagram of the structure of the encapsulation film of a battery before folding, according to another embodiment of this application;

[0090] Figure 14 is a top view of Figure 13;

[0091] Figure 15 is a partial structural schematic diagram of a battery according to an embodiment of this application;

[0092] Figure 16 is a schematic diagram of the structure of the encapsulation film of a battery according to an embodiment of this application before folding;

[0093] Figure 17 is a top view of Figure 16;

[0094] Figure 18 is a cross-sectional view of point AA in Figure 17.

[0095] Explanation of reference numerals in the attached drawings: 1. Electrode group; 101. Electrode tab; 102. First chamfer; 2. Encapsulation film; 201. First sub-encapsulation film; 202. Second sub-encapsulation film; 203. Receiving groove; 204. First fillet; 205. Second fillet; 206. Second chamfer; 207. Notch; 3. Encapsulation area. Detailed Implementation

[0096] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0097] The embodiments of this application are described below with reference to Figures 1 to 5.

[0098] According to an embodiment of this application, as shown in FIG1, a battery is provided, mainly comprising: an electrode assembly 1 and an encapsulation film 2. An electrode tab 101 is provided on one side of the electrode assembly 1. The encapsulation film 2 is divided into a first sub-encapsulation film 201 and a second sub-encapsulation film 202 by a fold line. The first sub-encapsulation film 201 extends concavely to form a receiving groove 203 for accommodating the electrode assembly 1. The second sub-encapsulation film 202 is folded along the fold line and is opposite to and adhered to the first sub-encapsulation film 201 to cover the electrode assembly 1. Encapsulation areas 3 surrounding the electrode assembly 1 are respectively provided on the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202. The groove depth H1 of the receiving groove 203 satisfies 0.1mm ≤ H1 ≤ 25mm. The thickness H2 of the encapsulation film 2 satisfies 0.05mm ≤ H2 ≤ 0.5mm and 0.02 ≤ H2 / H1 ≤ 0.5.

[0099] The battery provided in this application embodiment has a receiving groove 203 formed by punching a pit in the first sub-encapsulation film 201. The electrode assembly 1 after welding the tab 101 is placed into the receiving groove 203 of the first sub-encapsulation film 201. The second sub-encapsulation film 202 is folded along the fold line to adhere the first sub-encapsulation film 201 and the second sub-encapsulation film 202 together, and the electrode assembly 1 is covered inside the encapsulation film 2. Finally, the encapsulation area 3 on the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 is heat-fused to form a sealed and fixed structure. The structure is simple and convenient to use. By limiting the relationship between the depth H1 of the receiving groove 203 and the thickness H2 of the encapsulation film 2, as well as their ratio H2 / H1, it is possible to ensure that the encapsulation film 2 has a suitable thickness, balancing puncture resistance and bending flexibility, thus preventing cracking during battery charging and discharging expansion. It also prevents the encapsulation film 2 from being subjected to excessive shear force and failing when the thickness H2 of the encapsulation film 2 is too small and the depth H1 of the receiving groove 203 is too large when denting is made on the first sub-encapsulation film 201. In addition, it can also ensure that the encapsulation film 2 has a certain margin, avoiding the waste of material in the encapsulation film 2 due to the excessive thickness H2 of the encapsulation film 2 and the insufficient depth H1 of the receiving groove 203, and improving the space utilization rate of the battery.

[0100] In traditional punching processes, to facilitate the assembly of electrode assembly 1, the depth of the receiving groove 203 is typically designed to be 1.1 to 1.2 times the thickness of electrode assembly 1, providing buffer space for assembly and preventing electrode assembly 1 from being squeezed by the encapsulation film 2. This application embodiment further defines the proportional relationship between the groove depth H1 of the receiving groove 203 and the thickness H2 of the encapsulation film 2. Specifically, if H2 / H1 is less than 0.02, the encapsulation film 2 is relatively thin, and the groove depth of the receiving groove 203 is relatively large. The first sub-encapsulation film 201 may break and fail under significant shear force. If H2 / H1 is greater than 0.5, the encapsulation film 2 has excessive material and a large thickness allowance, wasting material. In the embodiments of this application, H2 / H1 can be 0.02, 0.1, 0.5, etc. Moreover, after the encapsulation area 3 is heat-fused and fixed, the thickness of the encapsulation area 3 is compressed to 60% to 70% of the original thickness. By limiting the ratio between the depth H1 of the receiving groove 203 and the thickness H2 of the encapsulation film 2, it is also possible to ensure that the encapsulation area 3 has sufficient sealing strength, avoid melting through or poor sealing during heat fusion, and avoid excessive thickness of the encapsulation area 3, which would lead to increased heat fusion time and damage to the internal electrode assembly 1, thereby significantly improving the battery's yield.

[0101] Specifically, please refer to Figure 3, where the fold line is OO as shown in Figure 3. The tab 101 includes a positive tab and a negative tab, which are spaced apart on the side of the electrode assembly 1 away from the fold line. The battery can be a rectangular structure, and the encapsulation film 2 is correspondingly square-shaped. The fold line can be the centerline of the length direction of the encapsulation film 2. The first sub-encapsulation film 201 and the second sub-encapsulation film 202 each have continuous encapsulation areas 3 on three sides away from the fold line. After the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are folded, their encapsulation areas 3 are adhered together, and the first sub-encapsulation film 201 and the second encapsulation film 202 are fixedly bonded through the heat-sealing encapsulation area 3. Please refer to arrow L in Figure 3 for the length direction of the encapsulation film 2, and arrow W in Figure 3 for the width direction of the encapsulation film 2.

[0102] Of course, in other alternative implementations, the battery can also be in other shapes, such as a disc, an elliptical cylinder, etc. Correspondingly, the encapsulation film 2 and the electrode assembly 1 are adapted to each other.

[0103] It should be noted that the material of the encapsulation film 2 in this embodiment can be selected according to the actual situation, for example, the encapsulation film 2 is an aluminum-plastic film.

[0104] In one embodiment, referring to Figure 5, the bottom of the receiving groove 203 is connected to the groove wall of the receiving groove 203 via a first arc, and the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm. By limiting the radius of the first arc, stress concentration can be reduced and the stability of the battery can be improved. If R1 is less than 0.3mm, when a dent is punched on the first sub-encapsulation film 201, the first sub-encapsulation film 201 will be subjected to a large shear force, causing the first sub-encapsulation film 201 to break and fail at the first arc. If R1 is greater than 5mm, the first arc will interfere with the edge of the electrode assembly 1 and crush the electrode assembly 1, causing damage to the electrode assembly 1, thereby causing a short circuit in the battery.

[0105] Furthermore, in one embodiment, when 0.02≤H2 / H1<0.1, the radius R1 of the first arc satisfies 1mm≤R1≤5mm.

[0106] When 0.1≤H2 / H1≤0.5, the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm.

[0107] For example, when H2 / H1 is 0.05, the radius R1 of the first arc can be 1mm, 2mm, 5mm, etc. When H2 / H1 is 0.3, the radius R1 of the first arc can be 0.3mm, 1mm, 2.5mm, 5mm, etc. When H2 / H1 is 0.5, the radius R1 of the first arc can be 3mm, 4mm, 5mm, etc.

[0108] The radius of the first arc is set according to the ratio of the thickness of the encapsulation film 2 to the depth of the receiving groove 203, which can further reduce stress concentration and improve the stability of the battery.

[0109] In one embodiment, referring to Figures 4 and 5, the wall of the receiving groove 203 is inclined relative to the bottom of the groove, so that the area of ​​the opening of the receiving groove 203 is larger than the area of ​​the bottom of the groove. By setting the wall of the receiving groove 203 to be inclined and the area of ​​the opening of the receiving groove 203 being larger than the area of ​​the bottom of the groove, it is easier to install and limit the electrode assembly 1, reduce the offset of the electrode assembly 1, thereby providing better support for the electrode assembly 1, ensuring that the encapsulation film 2 can uniformly cover the electrode assembly 1, and improving the encapsulation quality.

[0110] Further, in one embodiment, referring to Figures 4 and 5, the projected width H3 of the groove wall of the receiving groove 203 in the height direction of the encapsulation film 2 satisfies 0.1mm≤H3≤20mm and 0.2≤H3 / H1≤0.8. For example, H3 / H1 can be 0.2, 0.3, 0.5, 0.8, etc. By limiting the ratio between the groove depth of the receiving groove 203 and the projected width of the groove wall of the receiving groove 203 in the height direction of the encapsulation film 2, the stability of the encapsulation film 2 during the punching process can be ensured, and the space utilization rate can be improved. If H3 / H1 is less than 0.2, the first sub-encapsulation film 201 is prone to being subjected to large shear forces during punching, resulting in the first sub-encapsulation film 201 breaking and failing. If H3 / H1 is greater than 0.8, H3 is too long, the groove wall cannot effectively support the electrode group 1, the electrode group 1 is easily damaged, and a large gap space is formed between the groove wall and the electrode group 1, resulting in poor space utilization.

[0111] Specifically, please refer to arrow H in Figure 4 for the height direction of the encapsulation film 2.

[0112] In one embodiment, referring to Figures 2 and 4, the cross-section of the receiving groove 203 is an inverted trapezoid, and adjacent groove walls of the receiving groove 203 are connected by a second circular arc. The radius R2 of the second circular arc satisfies 0.5mm ≤ R2 ≤ 5mm. For example, R2 can be 0.5mm, 1mm, 2mm, 3mm, 5mm, etc. The inverted trapezoidal cross-section of the receiving groove 203 and the connection between adjacent groove walls of the receiving groove 203 by the second circular arc can reduce stress concentration. By limiting the radius range of the second circular arc, the stability and space utilization of the encapsulation film 2 during the punching process can be further improved. If R2 is less than 0.5mm, the first sub-encapsulation film 201 is prone to being subjected to large shear forces during punching, leading to the failure of the first sub-encapsulation film 201. If R2 is greater than 5mm, the second circular arc will interfere with the edge of the electrode assembly 1 and crush the electrode assembly 1, causing damage to the electrode assembly 1.

[0113] In one embodiment, referring to Figures 4 and 5, the opening of the receiving groove 203 is connected to the top surface of the encapsulation film 2 via a third arc, the radius R3 of which satisfies 0.5mm≤R3≤5mm. This connection between the opening of the receiving groove 203 and the top surface of the encapsulation film 2 reduces stress concentration at the connection point, preventing damage to the encapsulation film 2. It also facilitates smooth bonding of the first sub-encapsulation film 201 and the second sub-encapsulation film 202, thereby facilitating the encapsulation of the electrode assembly 1 and improving encapsulation quality.

[0114] Furthermore, in one embodiment, when 0.02≤H2 / H1<0.1, the radius R3 of the third arc satisfies 1.5mm≤R3≤5mm.

[0115] When 0.1≤H2 / H1≤0.5, the radius R3 of the third arc satisfies 0.5mm≤R3≤5mm.

[0116] The radius of the third arc is set according to the ratio of the thickness of the encapsulation film 2 to the depth of the receiving groove 203, which can further reduce stress concentration and improve the stability of the battery. If R3 is less than 0.5mm, the first sub-encapsulation film 201 is prone to large shear force when punching the groove, causing the first sub-encapsulation film 201 to break and fail at the third arc. If R3 is greater than 5mm, the distance X between the groove edge of the receiving groove 203 and the fold line needs to be increased accordingly, wasting material and space.

[0117] In one embodiment, referring to Figure 3, the distance X between the edge of the receiving groove 203 and the fold line satisfies 1mm + R3 ≤ X ≤ 30mm. By limiting the size range between the distance X between the edge of the receiving groove 203 and the fold line and the radius of the third arc, the tensile stress on the encapsulation film 2 during punching can be reduced, thus improving the encapsulation quality. If the distance between the edge of the receiving groove 203 and the fold line is too small, the first sub-encapsulation film 201 is prone to cracking at the opening of the receiving groove 203 when the second sub-encapsulation film 202 is folded, leading to encapsulation failure.

[0118] For example, when H2 / H1 is 0.05, the radius R3 of the third arc can be 1.5mm, 2mm, 5mm, etc. Correspondingly, the distance X between the edge of the groove 203 and the fold line can be 3mm, 4mm, 6mm, etc. When H2 / H1 is 0.3, the radius R3 of the third arc can be 0.5mm, 4mm, 5mm, etc. Correspondingly, the distance X between the edge of the groove 203 and the fold line can be 6mm, 10mm, 15mm, etc. When H2 / H1 is 0.5, the radius R3 of the third arc can be 1mm, 2mm, 3mm, etc. Correspondingly, the distance X between the edge of the groove 203 and the fold line can be 3mm, 5mm, 8mm, etc.

[0119] The process parameters of the battery in the embodiments of this application are further described in detail below with reference to specific embodiments. In the following embodiments and comparative examples, the battery has a rectangular structure, the encapsulation film 2 is correspondingly square, and the fold line is the centerline of the length direction of the encapsulation film 2. The bottom of the receiving groove 203 is connected to the groove wall of the receiving groove 203 by a first arc, the cross-section of the receiving groove 203 is an inverted trapezoid, adjacent groove walls of the receiving groove 203 are connected by a second arc, and the groove opening of the receiving groove 203 is connected to the top surface of the encapsulation film 2 by a third arc. It should be noted that these examples should not be construed as limiting the scope of protection claimed in this application.

[0120] Example 1:

[0121] The depth H1 of the receiving groove 203 is 25mm, the thickness H2 of the encapsulation film 2 is 0.5mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 12.5mm. Therefore, H2 / H1 = 0.02, which is the minimum value in this embodiment, and H3 / H1 = 0.5. The radius R1 of the first arc is 3mm. The radius R3 of the third arc is 4mm. The test verification results after battery production line testing are shown in Table 1.

[0122] Example 2:

[0123] The depth H1 of the receiving groove 203 is 4 mm, the thickness H2 of the encapsulation film 2 is 0.32 mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 2 mm. Therefore, H2 / H1 = 0.08, and H3 / H1 = 0.5. The radius R1 of the first arc is 1 mm, which is the minimum value in this embodiment. The radius R3 of the third arc is 2 mm. The test verification results after battery production line testing are shown in Table 1.

[0124] Example 3:

[0125] The groove depth H1 of the receiving groove 203 is 1 mm, the thickness H2 of the encapsulation film 2 is 0.45 mm, and the projected width H3 of the groove wall of the receiving groove 203 in the height direction of the encapsulation film 2 is 0.3 mm. Therefore, H2 / H1 = 0.45, and H3 / H1 = 0.3. The radius R1 of the first arc is 0.3 mm, which is the minimum value in this embodiment. The radius R3 of the third arc is 0.6 mm. The test verification results after battery production line testing are shown in Table 1.

[0126] Example 4:

[0127] The groove depth H1 of the receiving groove 203 is 4 mm, the thickness H2 of the encapsulation film 2 is 0.32 mm, and the projected width H3 of the groove wall of the receiving groove 203 in the height direction of the encapsulation film 2 is 1.2 mm. Therefore, H2 / H1 = 0.08, and H3 / H1 = 0.3. The radius R1 of the first arc is 2 mm. The radius R3 of the third arc is 1.6 mm, which is close to the minimum value in the embodiment of this application. The test verification results after battery production line testing are shown in Table 1.

[0128] Example 5:

[0129] The groove depth H1 of the receiving groove 203 is 1 mm, the thickness H2 of the encapsulation film 2 is 0.45 mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 0.7 mm. Therefore, H2 / H1 = 0.45, and H3 / H1 = 0.7. The radius R1 of the first arc is 0.4 mm. The radius R3 of the third arc is 0.5 mm, which is the minimum value in this embodiment. The test verification results after battery production line testing are shown in Table 1.

[0130] Example 6:

[0131] The depth H1 of the receiving groove 203 is 15mm, the thickness H2 of the encapsulation film 2 is 0.3mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 3mm. Therefore, H2 / H1 = 0.02 and H3 / H1 = 0.2, which are the minimum values ​​in this embodiment. The radius R1 of the first arc is 2mm. The radius R3 of the third arc is 5mm. The test verification results after battery production line testing are shown in Table 1.

[0132] Comparative Example 1:

[0133] The depth H1 of the receiving groove 203 is 25mm, the thickness H2 of the encapsulation film 2 is 0.25mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 12.5mm. Therefore, H2 / H1 = 0.01, which is less than 0.02, and H3 / H1 = 0.5. The radius R1 of the first arc is 3mm. The radius R3 of the third arc is 4mm. The test verification results after battery production line testing are shown in Table 1.

[0134] Comparative Example 2:

[0135] The depth H1 of the receiving groove 203 is 4mm, the thickness H2 of the encapsulation film 2 is 0.32mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 2mm. Therefore, H2 / H1 = 0.08, and H3 / H1 = 0.5. The radius R1 of the first arc is 0.9mm, which is less than 1mm. The radius R3 of the third arc is 2mm. The test verification results after battery production line testing are shown in Table 1.

[0136] Comparative Example 3:

[0137] The depth H1 of the receiving groove 203 is 1 mm, the thickness H2 of the encapsulation film 2 is 0.45 mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 0.3 mm. Therefore, H2 / H1 = 0.45, and H3 / H1 = 0.3. The radius R1 of the first arc is 0.2 mm, which is less than 0.3 mm. The radius R3 of the third arc is 0.6 mm. The test verification results after battery production line testing are shown in Table 1.

[0138] Comparative Example 4:

[0139] The depth H1 of the receiving groove 203 is 4mm, the thickness H2 of the encapsulation film 2 is 0.32mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 1.2mm. Therefore, H2 / H1 = 0.08, and H3 / H1 = 0.3. The radius R1 of the first arc is 2mm. The radius R3 of the third arc is 1.4mm, which is less than 1.5mm. The test verification results after battery production line testing are shown in Table 1.

[0140] Comparative Example 5:

[0141] The depth H1 of the receiving groove 203 is 1 mm, the thickness H2 of the encapsulation film 2 is 0.45 mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 0.7 mm. Therefore, H2 / H1 = 0.45, and H3 / H1 = 0.7. The radius R1 of the first arc is 0.4 mm. The radius R3 of the third arc is 0.4 mm, which is less than 0.5 mm. The test verification results after battery production line testing are shown in Table 1.

[0142] Comparative Example 6:

[0143] The depth H1 of the receiving groove 203 is 20mm, the thickness H2 of the encapsulation film 2 is 0.5mm, and the projected width H3 of the groove wall of the receiving groove 203 along the height direction of the encapsulation film 2 is 2mm. Therefore, H2 / H1 = 0.025, H3 / H1 = 0.1, which is less than 0.2. The radius R1 of the first arc is 3mm. The radius R3 of the third arc is 3mm. The test verification results after battery production line testing are shown in Table 1.

[0144] Table 1: Test Results

[0145] As shown in Table 1, in Examples 1 to 4, the following conditions are met: 0.1mm ≤ H1 ≤ 25mm, 0.05mm ≤ H2 ≤ 0.5mm, 0.1mm ≤ H3 ≤ 20mm, 0.02 ≤ H2 / H1 ≤ 0.5, and 0.2 ≤ H3 / H1 ≤ 0.8. When 0.02 ≤ H2 / H1 < 0.1, 1mm ≤ R1 ≤ 5mm and 1.5mm ≤ R3 ≤ 5mm; when 0.1 ≤ H2 / H1 ≤ 0.5, 0.3mm ≤ R1 ≤ 5mm and 0.5mm ≤ R3 ≤ 5mm. Therefore, the encapsulation film 2 can be guaranteed to have a suitable thickness while saving materials.

[0146] In Comparative Example 1, H2 / H1 = 0.01, which is less than 0.02 and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, the stretching surface in the height direction of the receiving groove 203 cracks and breaks, resulting in encapsulation failure.

[0147] In Comparative Example 2, H2 / H1 = 0.08, and the radius R1 of the first arc is 0.9 mm, which is less than 1 mm and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, cracks and damage occur at the position of the first arc.

[0148] In Comparative Example 3, H2 / H1 = 0.45, and the radius R1 of the first arc is 0.2 mm, which is less than 0.3 mm and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, cracks and damage occur at the position of the first arc.

[0149] In Comparative Example 4, H2 / H1 = 0.08, and the radius R3 of the third arc is 1.4 mm, which is less than 1.5 mm and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, cracks and damage occur at the position of the third arc.

[0150] In Comparative Example 5, H2 / H1 = 0.45, and the radius R3 of the third arc is 0.4 mm, which is less than 0.5 mm and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, cracks and damage occur at the position of the third arc.

[0151] In Comparative Example 6, H3 / H1 = 0.1, which is less than 0.2 and lower than the minimum value in the embodiments of this application. When the first sub-encapsulation film 201 is punched, the stretching surface in the height direction of the receiving groove 203 cracks and breaks, resulting in encapsulation failure.

[0152] The embodiments of this application are described below with reference to Figures 6 to 14.

[0153] According to an embodiment of this application, referring to Figures 6 and 10, a battery is provided, mainly comprising: an electrode assembly 1 and an encapsulation film 2. An electrode tab 101 is provided on one side of the electrode assembly 1. The encapsulation film 2 is provided with a receiving groove 203 for mounting the electrode assembly 1, the groove wall of the receiving groove 203 being inclined at an obtuse angle relative to the groove bottom. In the width direction of the battery, the width W1 of the electrode assembly 1 and the width W2 of the receiving groove 203 satisfy 30mm≤W1≤200mm, 28mm≤W2≤250mm, and 0.8≤W1 / W2≤1.05. In the length direction of the battery, the length L1 of the electrode assembly 1 and the length L2 of the receiving groove 203 satisfy 50mm≤L1≤400mm, 45mm≤L2≤500mm, and 0.8≤L1 / L2≤1.1.

[0154] Therefore, the battery provided in this application embodiment, by limiting the dimensions and proportions of the electrode assembly 1 and the receiving groove 203 in the length and width directions of the battery, can provide suitable installation space for the electrode assembly 1 and effectively fix the electrode assembly 1, avoiding interference between the electrode assembly 1 and the receiving groove 203 and damage to the electrode assembly 1, thus improving the installation reliability and yield of the battery. Furthermore, the groove wall of the receiving groove 203 is inclined at an obtuse angle relative to the groove bottom, facilitating the smooth installation of the electrode assembly 1 into the receiving groove 203, reducing electrode assembly 1 offset, thereby providing better support for the electrode assembly 1, and ensuring that the encapsulation film 2 completely covers and tightly wraps the electrode assembly 1, improving the sealing effect. In addition, it can optimize the use of the encapsulation film 2 and avoid material waste.

[0155] It should be noted that, in the width direction of the battery, the width of the groove 203 needs to be greater than the width of the electrode assembly 1. If the ratio W1 / W2 between the width of the electrode assembly 1 and the width of the groove 203 is greater than 1.05, then the width of the electrode assembly 1 is too large and the width of the groove 203 is too small. This can easily cause the electrode assembly 1 to interfere with the groove 203 in the width direction, leading to damage and ultimately a short circuit in the battery. If W1 / W2 is less than 0.8, then the width of the groove 203 is too large and the width of the electrode assembly 1 is too small, wasting space in the groove 203 and causing material waste. Furthermore, the electrode assembly 1 can easily move within the groove 203, leading to damage. For example, W1 / W2 can be 0.8, 0.9, 1, 1.05, etc.

[0156] Similarly, along the length of the battery, the opening length of the receiving groove 203 needs to be greater than the length of the electrode assembly 1. If the ratio L1 / L2 between the length of the electrode assembly 1 and the length of the receiving groove 203 is greater than 1.1, then the length of the electrode assembly 1 is too large and the length of the receiving groove 203 is too small. The electrode assembly 1 is prone to interference with the receiving groove 203 along its length, leading to damage to the electrode assembly 1 and ultimately causing a short circuit in the battery. If L1 / L2 is less than 0.8, then the length of the receiving groove 203 is too large and the length of the electrode assembly 1 is too small, wasting space in the receiving groove 203, resulting in material waste, and the electrode assembly 1 is prone to moving within the receiving groove 203, causing damage to the electrode assembly 1. For example, L1 / L2 can be 0.8, 0.9, 1, 1.1, etc.

[0157] In traditional punching processes, to facilitate the assembly of the electrode assembly 1 and processing, the wall of the receiving groove 203 is generally perpendicular to the bottom of the groove. The length and width of the receiving groove 203 are usually designed to be 1.1 to 1.2 times the length and width of the electrode assembly 1, leaving buffer space for the assembly of the electrode assembly 1 and preventing the electrode assembly 1 from being squeezed by the encapsulation film 2. In the embodiments of this application, the wall of the receiving groove 203 is set at an obtuse angle to the bottom of the groove, and the ratio between the width of the electrode assembly 1 and the width of the receiving groove 203, as well as the ratio between the length of the electrode assembly 1 and the length of the receiving groove 203, are further defined, which makes it easier to install the electrode assembly 1 and significantly reduces the probability of interference between the electrode assembly 1 and the receiving groove 203, thereby improving the encapsulation quality and yield of the battery.

[0158] Specifically, please refer to arrow L in Figure 7 for the length direction of the battery, and arrow W in Figure 7 for the width direction of the battery. Referring to Figure 7, the tab 101 includes a positive tab and a negative tab, which are spaced apart on the side of the electrode group 1 away from the fold line.

[0159] It should be noted that the material of the encapsulation film 2 in this embodiment can be selected according to the actual situation, for example, the encapsulation film 2 is an aluminum-plastic film.

[0160] In one embodiment, the encapsulation film 2 is divided into a first sub-encapsulation film 201 and a second sub-encapsulation film 202 by a fold line. At least one of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 extends concavely to form a receiving groove 203. The first sub-encapsulation film 201 and the second sub-encapsulation film 202 are folded along the fold line and are opposite to each other and attached to cover the electrode assembly 1. The periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are respectively provided with an encapsulation area 3 surrounding the electrode assembly 1.

[0161] In this embodiment of the application, during assembly, the electrode assembly 1 is first placed into the receiving groove 203, the encapsulation film 2 is folded along the fold line, the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are attached together, and the electrode assembly 1 is wrapped in the receiving groove 203. Finally, the encapsulation area 3 on the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 is heat-fused to form a sealed and fixed structure. The structure is simple and convenient to use.

[0162] It should be noted that the encapsulation film 2 in this embodiment can be selected as either a single-pit or double-pit form as needed. Referring to Figures 13 and 14, the single-pit form refers to a receiving groove 203 formed by recessed extension on the first sub-encapsulation film 201 or the second sub-encapsulation film 202. Referring to Figures 10 to 12, the double-pit form refers to receiving grooves 203 formed by recessed extension on both the first and second sub-encapsulation films 201 and 202, respectively.

[0163] For example, in the double-pit configuration, the fold line is line OO in Figure 11. After the encapsulation film 2 is folded along the fold line, the edges of the receiving grooves 203 on the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are aligned, and the two receiving grooves 203 together form the cavity for receiving the electrode assembly 1.

[0164] In addition, the battery can be rectangular, and the encapsulation film 2 is correspondingly square. The fold line can be the centerline along the length of the encapsulation film 2. The first sub-encapsulation film 201 and the second sub-encapsulation film 202 each have continuous encapsulation areas 3 on three sides away from the fold line. After the encapsulation film 2 is folded, the encapsulation areas 3 of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are relatively attached to each other, and the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are fixedly bonded by the heat-sealing encapsulation area 3.

[0165] In one embodiment, referring to Figures 10 and 11, the first sub-encapsulation film 201 and the second sub-encapsulation film 202 each have a first rounded corner 204 at opposite ends of the fold line. The radius SR1 of the first rounded corner 204 satisfies 1mm ≤ SR1 ≤ 50mm. For example, the radius R1 of the first rounded corner 204 can be 1mm, 10mm, 20mm, 50mm, etc. By having the first rounded corner 204 at opposite ends of the fold line, rounded corners can be formed after the encapsulation film 2 is folded, preventing the corners of the folded encapsulation film 2 from scratching operators, improving battery operation safety, and facilitating transportation. Moreover, the first rounded corner 204 can also effectively disperse stress, preventing the encapsulation film 2 from cracking at the corners, thereby improving the stability and encapsulation quality of the battery.

[0166] In one embodiment, referring to Figure 7, the width W3 of the encapsulation region 3 in the width direction of the battery satisfies 1mm ≤ W3 ≤ 50mm. For example, the width W3 of the encapsulation region 3 can be 1mm, 10mm, 20mm, 50mm, etc. By limiting the width of the encapsulation region 3 to between 1mm and 50mm, it helps to control the tension of the encapsulation film 2, avoiding uneven stretching of the encapsulation film 2 during the encapsulation process due to the encapsulation region 3 being too wide or too narrow, thereby affecting the encapsulation effect. It also ensures that the encapsulation film 2 tightly covers the electrode assembly 1, preventing the generation of defects such as bubbles and wrinkles, thereby improving the battery encapsulation yield.

[0167] Further, in one embodiment, referring to Figure 11, the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 in the width direction of the battery satisfies W3+0.5mm≤L3≤50mm. By limiting the distance between the edge of the receiving groove 203 and the edge of the first rounded corner 204, sufficient space for heat sealing can be provided, avoiding insufficient heat sealing width leading to encapsulation failure. If the distance between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is too small, the space for heat sealing at the first rounded corner 204 will be insufficient. After heat sealing, the weld width of the first rounded corner 204 will be too small compared to other areas, posing a risk of leakage and leading to seal failure. Especially when the width W3 of the encapsulation area 3 is biased towards the lower limit, and the first rounded corner 204 is slightly larger, if the distance L3 is less than W3+0.5mm, seal failure is likely to occur.

[0168] In one embodiment, referring to Figure 8, when the battery thickness T ≥ 20 mm, the first sub-encapsulation film 201 and the second sub-encapsulation film 202 extend concavely to form receiving grooves 203. The concave extension of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 to form receiving grooves 203 constitutes a double-pit process. This facilitates uniform force distribution on both sides of the battery during discharge cycle expansion, helping to offset the influence of expansion force on the tensile force of the encapsulation film 2, thereby reducing the failure risk of the encapsulation film 2 or the heat-sealed edge. When the battery thickness T ≥ 20 mm, if a single-pit form is used, the receiving groove 203 will be deeper and thinner. The plane where the sub-encapsulation film without the receiving groove 203 is located is not easily expanded and deformed, causing the expansion deformation force to concentrate on the sub-encapsulation film with the receiving groove 203. This makes the sub-encapsulation film with the receiving groove 203 susceptible to deformation and even cracking.

[0169] In one embodiment, when the first sub-encapsulation film 201 or the second sub-encapsulation film 202 extends inward to form a receiving groove 203, the distance L4 between the side of the receiving groove 203 near the fold line and the fold line and the depth H1 of the receiving groove 203 satisfy 2mm≤L4≤30mm, 0.5mm≤H1≤50mm, and 0.2≤L4 / H1≤100.

[0170] The first sub-encapsulation film 201 or the second sub-encapsulation film 202 extends inward to form a receiving groove 203. That is, in the single-groove process, by limiting the distance between the side of the receiving groove 203 near the fold line and the fold line, and the ratio of the distance to the depth of the receiving groove 203, the encapsulation quality of the battery can be improved. If the ratio of the distance to the depth of the receiving groove 203 is too small, the fold of the encapsulation film 2 will be too thin and easily deformed, with poor strength, and the encapsulation film 2 will be easily damaged after folding. If the ratio of the distance to the depth of the receiving groove 203 is too large, space and materials will be wasted.

[0171] For example, referring to FIG14, a receiving groove 203 is formed by recessed extension on the first sub-encapsulation film 201.

[0172] In one embodiment, referring to Figures 10 and 11, the encapsulation film 2 is square-shaped, and has second rounded corners 205 at its four corners. The radius SR2 of the second rounded corners 205 satisfies 1mm ≤ SR2 ≤ 50mm. For example, the radius SR2 of the second rounded corners 205 can be 1mm, 5mm, 10mm, 30mm, 50mm, etc. By providing second rounded corners 205 at the four corners of the encapsulation film 2, it is possible to further prevent the corners of the encapsulation film 2 from scratching operators, improve battery operation safety, and facilitate battery transportation.

[0173] Furthermore, in one embodiment, referring to Figure 11, the distance L5 between the second rounded corner 205 and the edge of the receiving groove 203 satisfies 3mm ≤ L5 ≤ 50mm. For example, the distance L5 between the second rounded corner 205 and the edge of the receiving groove 203 can be 3mm, 5mm, 20mm, 40mm, 50mm, etc. By limiting the distance between the second rounded corner 205 and the edge of the receiving groove 203, a sufficiently wide encapsulation area 3 can be provided, reducing the risk of encapsulation failure due to an excessively narrow heat-melting width of the encapsulation area 3.

[0174] Of course, in other alternative implementations, the battery can also be in other shapes, such as a disc, an elliptical cylinder, etc. Correspondingly, the encapsulation film 2 and the electrode assembly 1 are adapted to each other.

[0175] The process parameters of the battery in this application embodiment are further described in detail below with reference to specific embodiments. In the following embodiments and comparative examples, the battery has a rectangular structure, the encapsulation film 2 is correspondingly square, and the fold line is the centerline of the length direction of the encapsulation film 2. The cross-section of the receiving groove 203 is an inverted trapezoid. It should be noted that these examples should not be construed as limiting the scope of protection claimed in this application.

[0176] Example S1:

[0177] The encapsulation film 2 adopts a single-pit design, with a recessed groove 203 formed on the first sub-encapsulation film 201. The width W1 of the electrode assembly 1 is 31.5 mm, and the bottom width W2 of the groove 203 is 30 mm, so W1 / W2 = 1.05, which is the maximum value in this embodiment. The length L1 of the electrode assembly 1 is 50 mm, and the bottom length L2 of the groove 203 is 52 mm, so L1 / L2 = 0.96. The radius SR1 of the first rounded corner 204 is 2 mm, the width W3 of the encapsulation area 3 is 2 mm, and the distance L3 between the edge of the groove 203 and the edge of the first rounded corner 204 is 3 mm. The distance L4 between the side of the groove 203 near the fold line and the fold line is 3 mm, and the depth H1 of the groove 203 is 3 mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0178] Example S2:

[0179] The encapsulation film 2 adopts a single-pit design, with a recessed groove 203 formed on the first sub-encapsulation film 201. The width W1 of the electrode assembly 1 is 50 mm, and the bottom width W2 of the groove 203 is 50 mm, so W1 / W2 = 1. The length L1 of the electrode assembly 1 is 77 mm, and the bottom length L2 of the groove 203 is 70 mm, so L1 / L2 = 1.1, which is the maximum value in this embodiment. The radius SR1 of the first rounded corner 204 is 10 mm, the width W3 of the encapsulation area 3 is 20 mm, and the distance L3 between the edge of the groove 203 and the edge of the first rounded corner 204 is 25 mm. The distance L4 between the side of the groove 203 near the fold line and the fold line is 10 mm, and the depth H1 of the groove 203 is 10 mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0180] Example S3:

[0181] The encapsulation film 2 adopts a single-pit design, with the first sub-encapsulation film 201 extending inward to form a receiving groove 203. The width W1 of the electrode assembly 1 is 30mm, and the bottom width W2 of the receiving groove 203 is 30mm, so W1 / W2 = 1. The length L1 of the electrode assembly 1 is 50mm, and the bottom length L2 of the receiving groove 203 is 50mm, so L1 / L2 = 1. The radius SR1 of the first rounded corner 204 is 1mm, which is the minimum value in this embodiment. The width W3 of the encapsulation area 3 is 2mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 3mm. The distance L4 between the side of the receiving groove 203 near the fold line and the fold line is 3mm, and the depth H1 of the receiving groove 203 is 3mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0182] Example S4:

[0183] The encapsulation film 2 adopts a double-pit design, with the first sub-encapsulation film 201 and the second sub-encapsulation film 202 respectively extending inward to form receiving grooves 203. The width W1 of the electrode assembly 1 is 60mm, and the bottom width W2 of the receiving groove 203 is 58mm, so W1 / W2 = 1.03. The length L1 of the electrode assembly 1 is 80mm, and the bottom length L2 of the receiving groove 203 is 75mm, so L1 / L2 = 1.07. The radius SR1 of the first rounded corner 204 is 5mm, and the width W3 of the encapsulation area 3 is 1mm, which is the minimum value in this embodiment. The distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 10mm. The thickness T of the battery is 25mm. The test verification results after battery production line testing are shown in Table 2.

[0184] Example S5:

[0185] The encapsulation film 2 adopts a double-pit design, with the first sub-encapsulation film 201 and the second sub-encapsulation film 202 respectively extending inward to form receiving grooves 203. The width W1 of the electrode assembly 1 is 40mm, and the bottom width W2 of the receiving groove 203 is 40mm, so W1 / W2 = 1. The length L1 of the electrode assembly 1 is 70mm, and the bottom length L2 of the receiving groove 203 is 70mm, so L1 / L2 = 1. The radius SR1 of the first rounded corner 204 is 5mm, the width W3 of the encapsulation area 3 is 5mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 10mm. The thickness T of the battery is 20mm. The test verification results after battery production line testing are shown in Table 2.

[0186] Example S6:

[0187] The encapsulation film 2 adopts a single-pit design, with a recessed groove 203 formed on the first sub-encapsulation film 201. The width W1 of the electrode assembly 1 is 35 mm, and the bottom width W2 of the groove 203 is 36 mm, so W1 / W2 = 0.97. The length L1 of the electrode assembly 1 is 50 mm, and the bottom length L2 of the groove 203 is 52 mm, so L1 / L2 = 0.96. The radius SR1 of the first rounded corner 204 is 3 mm, the width W3 of the encapsulation area 3 is 3 mm, and the distance L3 between the edge of the groove 203 and the edge of the first rounded corner 204 is 5 mm. The distance L4 between the side of the groove 203 near the fold line and the fold line is 3 mm, and the depth H1 of the groove 203 is 15 mm, so L4 / H1 = 0.2, which is the minimum value in this embodiment. The test verification results after battery production line testing are shown in Table 2.

[0188] Comparative Example S1:

[0189] The encapsulation film 2 adopts a single-pit design, with the first sub-encapsulation film 201 extending inward to form a receiving groove 203. The width W1 of the electrode assembly 1 is 32mm, and the bottom width W2 of the receiving groove 203 is 30mm, so W1 / W2 = 1.07, which is greater than 1.05. The length L1 of the electrode assembly 1 is 50mm, and the bottom length L2 of the receiving groove 203 is 52mm, so L1 / L2 = 0.96. The radius SR1 of the first rounded corner 204 is 2mm, the width W3 of the encapsulation area 3 is 2mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 3mm. The distance L4 between the side of the receiving groove 203 near the fold line and the fold line is 3mm, and the depth H1 of the receiving groove 203 is 3mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0190] Comparative Example S2:

[0191] The encapsulation film 2 adopts a single-pit design, with the first sub-encapsulation film 201 extending inward to form a receiving groove 203. The width W1 of the electrode assembly 1 is 50mm, and the bottom width W2 of the receiving groove 203 is 50mm, so W1 / W2 = 1. The length L1 of the electrode assembly 1 is 80mm, and the bottom length L2 of the receiving groove 203 is 70mm, so L1 / L2 = 1.14, which is greater than 1.1. The radius SR1 of the first rounded corner 204 is 10mm, the width W3 of the encapsulation area 3 is 20mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 25mm. The distance L4 between the side of the receiving groove 203 near the fold line and the fold line is 10mm, and the depth H1 of the receiving groove 203 is 10mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0192] Comparative Example S3:

[0193] The encapsulation film 2 adopts a single-pit design, with the first sub-encapsulation film 201 extending inward to form a receiving groove 203. The width W1 of the electrode assembly 1 is 30mm, and the bottom width W2 of the receiving groove 203 is 30mm, so W1 / W2 = 1. The length L1 of the electrode assembly 1 is 50mm, and the bottom length L2 of the receiving groove 203 is 50mm, so L1 / L2 = 1. The radius SR1 of the first rounded corner 204 is 0.5mm, which is less than 1mm. The width W3 of the encapsulation area 3 is 2mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 3mm. The distance L4 between the side of the receiving groove 203 near the fold line and the fold line is 3mm, and the depth H1 of the receiving groove 203 is 3mm, so L4 / H1 = 1. The test verification results after battery production line testing are shown in Table 2.

[0194] Comparative Example S4:

[0195] The encapsulation film 2 adopts a double-pit design, with the first sub-encapsulation film 201 and the second sub-encapsulation film 202 respectively extending inward to form receiving grooves 203. The width W1 of the electrode assembly 1 is 60mm, and the bottom width W2 of the receiving groove 203 is 58mm, so W1 / W2 = 1.03. The length L1 of the electrode assembly 1 is 80mm, and the bottom length L2 of the receiving groove 203 is 75mm, so L1 / L2 = 1.07. The radius SR1 of the first rounded corner 204 is 5mm, the width W3 of the encapsulation area 3 is 0.5mm, which is less than 1mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 10mm. The thickness T of the battery is 25mm. The test verification results after battery production line testing are shown in Table 2.

[0196] Comparative Example S5:

[0197] The encapsulation film 2 adopts a single-pit design, with the first sub-encapsulation film 201 extending inward to form a receiving groove 203. The width W1 of the electrode assembly 1 is 35mm, and the bottom width W2 of the receiving groove 203 is 36mm, so W1 / W2 = 0.97. The length L1 of the electrode assembly 1 is 50mm, and the bottom length L2 of the receiving groove 203 is 52mm, so L1 / L2 = 0.96. The radius SR1 of the first rounded corner 204 is 3mm, the width W3 of the encapsulation area 3 is 3mm, and the distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 is 5mm. The distance L4 between the side of the receiving groove 203 near the fold line and the fold line is 2mm, and the depth H1 of the receiving groove 203 is 12mm, so L4 / H1 = 0.17, which is less than 0.2. The test verification results after battery production line testing are shown in Table 2.

[0198] Table 2: Test Results

[0199] As can be seen from Table 2, in Examples S1 to S6, the following conditions are met: 30mm≤W1≤200mm, 28mm≤W2≤250mm, 0.8≤W1 / W2≤1.05, 50mm≤L1≤400mm, 45mm≤L2≤500mm, 0.8≤L1 / L2≤1.1, 1mm≤SR1≤50mm, 1mm≤W3≤50mm, and W3+0.5mm≤L3≤50mm; in the single-pit form, 2mm≤L4≤30mm, 0.5mm≤H1≤50mm, and 0.2≤L4 / H1≤100.

[0200] In Comparative Example S1, W1 / W2 = 1.07, which exceeds the maximum value of the embodiment of this application. The width of the electrode group 1 is too large and the width of the receiving groove 203 is too small. The electrode group 1 and the receiving groove 203 interfere with each other, causing the electrode group 1 to be damaged and ultimately causing the battery to short circuit.

[0201] In Comparative Example S2, L1 / L2 = 1.14, which exceeds the maximum value of the embodiment of this application. The length of the electrode group 1 is too large and the length of the receiving groove 203 is too small. The electrode group 1 and the receiving groove 203 interfere with each other, causing the electrode group 1 to be damaged and ultimately causing the battery to short circuit.

[0202] In Comparative Example S3, the radius SR1 of the first rounded corner 204 is 0.5 mm, which is less than the minimum value in the embodiments of this application. There is a large stress concentration at the corner of the encapsulation film 2, which causes the encapsulation film 2 to crack at the corner.

[0203] In Comparative Example S4, the width W3 of the encapsulation area 3 is 0.5mm, which is less than the minimum value in the embodiments of this application. The encapsulation area 3 is too narrow, which causes the encapsulation film 2 to be stretched unevenly during the encapsulation process, resulting in encapsulation failure.

[0204] In Comparative Example S5, L4 / H1 = 0.17, which is less than the minimum value in the embodiments of this application. The folded part of the encapsulation film 2 is too thin and has poor strength. After folding, the encapsulation film 2 is damaged.

[0205] The embodiments of this application are described below with reference to Figures 15 to 18.

[0206] According to an embodiment of this application, referring to FIG15, a battery is provided, including: an electrode assembly 1 and an encapsulation film 2. An electrode tab 101 is provided on one side of the electrode assembly 1. The encapsulation film 2 is divided into a first sub-encapsulation film 201 and a second sub-encapsulation film 202 by a fold line. The first sub-encapsulation film 201 and the second sub-encapsulation film 202 extend concavely to form receiving grooves 203 for accommodating the electrode assembly 1. The second sub-encapsulation film 202 is folded along the fold line and faces and adheres to the first sub-encapsulation film 201 to cover the electrode assembly 1. Encapsulation areas 3 surrounding the electrode assembly 1 are respectively provided on the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202. The distance TL1 between adjacent edges of the two receiving grooves 203 and the depth H1 of the receiving grooves 203 satisfy 0.6 ≤ TL1 / H1 ≤ 100.

[0207] Therefore, the battery provided in this application embodiment has recesses formed by punching pits in the first sub-encapsulation film 201 and the second sub-encapsulation film 202, respectively. The electrode assembly 1 after welding the tab 101 is placed into the recess 203 of the first sub-encapsulation film 201, and the second sub-encapsulation film 202 is folded along the fold line to fit the first sub-encapsulation film 201 and the second sub-encapsulation film 202 together. The electrode assembly 1 is then covered in the two recesses 203. Finally, the encapsulation area 3 on the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 is heat-fused to form a sealed and fixed structure. The structure is simple and easy to install. By limiting the ratio TL1 / H1 between the distance TL1 between the adjacent edges of the two receiving grooves 203 and the depth H1 of the receiving groove 203, a suitable distance between the receiving grooves 203 can be reserved when stamping the depth of the receiving grooves 203, thereby improving the battery packaging quality and saving the material of the encapsulation film 2. This avoids the receiving grooves 203 being too deep and the distance between the adjacent edges of the two receiving grooves 203 being too small, which would cause the encapsulation film 2 to be stretched and deformed too thin during the punching process, resulting in poor strength and cracking, thus causing the battery seal to fail.

[0208] In traditional punching processes, to facilitate the assembly of electrode assembly 1, the depth of the receiving groove 203 is typically designed to be 1.1 to 1.2 times the thickness of electrode assembly 1, leaving buffer space for electrode assembly 1 assembly and preventing electrode assembly 1 from being squeezed by the encapsulation film 2. This application embodiment further defines the ratio TL1 / H1 between the distance TL1 between adjacent edges of the two receiving grooves 203 and the depth H1 of the receiving groove 203. The depths of the receiving grooves 203 of both the first sub-encapsulation film 201 and the second sub-encapsulation film 202 need to be within this range, and the depths of the receiving grooves 203 of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 can be equal. If TL1 / H1 is less than 0.6, the receiving groove 203 is too deep and the distance between adjacent edges of the two receiving grooves 203 is too small, which can easily lead to the encapsulation film 2 cracking during punching, causing battery sealing failure. If TL1 / H1 is greater than 100, the overall size of the battery is too large, wasting battery space and encapsulation film 2 material. Moreover, the greater the thickness of the encapsulation area 3, the longer the heat-sealing time, which can easily damage the electrode assembly 1. In the embodiments of this application, TL1 / H1 can be 0.6, 1, 10, 100, etc.

[0209] Specifically, please refer to Figure 17. The fold line is OO as shown in Figure 17. After the encapsulation film 2 is folded along the fold line, the edges of the receiving grooves 203 on the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are aligned, and the two receiving grooves 203 together form a cavity for accommodating the electrode assembly 1. The electrode tab 101 includes a positive electrode tab and a negative electrode tab, which are spaced apart on the side of the electrode assembly 1 away from the fold line.

[0210] It should be noted that the material of the encapsulation film 2 in this embodiment can be selected according to the actual situation, for example, the encapsulation film 2 is an aluminum-plastic film.

[0211] In one embodiment, referring to Figure 17, the distance TL1 between adjacent edges of the two receiving grooves 203 satisfies 1mm≤TL1≤50mm, and the depth H1 of the receiving groove 203 satisfies 0.5mm≤H1≤50mm. By limiting the distance between adjacent edges of the two receiving grooves 203, sufficient strength can be ensured when the encapsulation film 2 is folded. When denting occurs, the encapsulation film 2 near the edge of the receiving groove 203 is subjected to tensile deformation and stress. If the distance TL1 between adjacent edges of the two receiving grooves 203 is too small, the edge of the receiving groove 203 is prone to cracking when the encapsulation film 2 is folded, and the battery is also at risk of cracking and damage in subsequent use. By limiting the depth of the receiving groove 203, sufficient buffer space can be provided for the installation of the electrode assembly 1, preventing the electrode assembly 1 from being deformed by pressure or the tab 101 from bending. It can also limit the movement of the electrode assembly 1 within the receiving groove 203, avoiding short circuits in the battery due to vibration.

[0212] Further, in one embodiment, referring to Figure 17, the distance TL2 between the sides of the receiving groove 203 in the width direction of the encapsulation film 2 satisfies 2.5mm≤TL2≤100mm and 5≤TL2 / H1≤50. By limiting the distance TL2 between the sides of the receiving groove 203 in the width direction of the encapsulation film 2, a sufficiently wide encapsulation area 3 can be reserved for heat-sealing the first sub-encapsulation film 201 and the second sub-encapsulation film 202. Further limiting the ratio of TL2 / H1 can ensure the encapsulation quality of the battery. If the ratio of TL2 / H1 is less than 5, the TL2 is insufficient, and after the encapsulation area 3 shrinks after heat sealing, the melt width is too narrow, and the heat-sealing is prone to failure. If the ratio of TL2 / H1 is greater than 50, the TL2 is too large, wasting space and materials.

[0213] Specifically, the length direction of the encapsulation film 2 is shown by arrow L in Figure 17, and the width direction of the encapsulation film 2 is shown by arrow W in Figure 17.

[0214] Furthermore, in one embodiment, the spacing between the receiving groove 203 and the side of the encapsulation film 2 along its length is also between 2.5 mm and 100 mm, so as to leave a sufficiently wide encapsulation area 3 on the side of the encapsulation film away from the fold line.

[0215] It should be noted that the battery can be rectangular, and the encapsulation film 2 is correspondingly square. The fold line can be the centerline along the length of the encapsulation film 2. The first sub-encapsulation film 201 and the second sub-encapsulation film 202 each have continuous encapsulation areas 3 on three sides away from the fold line. After the encapsulation film 2 is folded, the encapsulation areas 3 of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are relatively attached to each other, and the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are fixedly bonded through the heat-sealing encapsulation area 3.

[0216] In one embodiment, referring to Figure 17, the encapsulation film 2 is square-shaped, and has a first chamfer 102 at each of the four corners. The dimension TL3 of the first chamfer 102 in the length direction of the encapsulation film 2 satisfies 1mm≤TL3≤50mm, and the dimension TW1 of the first chamfer 102 in the width direction of the encapsulation film 2 satisfies 1mm≤TW1≤50mm. By providing the first chamfer 102 at the four corners of the encapsulation film 2, it is possible to prevent the corners of the encapsulation film 2 from scratching personnel and to facilitate transportation. By limiting the dimensions of the first chamfer 102 in the length and width directions of the encapsulation film 2, stress concentration can be effectively reduced, preventing the encapsulation film 2 from tearing at the corners and improving the encapsulation quality of the battery.

[0217] Specifically, the dimension TL3 of the first chamfer 102 in the length direction of the encapsulation film 2 can be 1mm, 5mm, 25mm, or 50mm, and the dimension TW1 of the first chamfer 102 in the width direction of the encapsulation film 2 can be 1mm, 5mm, 25mm, or 50mm. The dimension TL3 of the first chamfer 102 in the length direction of the encapsulation film 2 and the dimension TW1 of the first chamfer 102 in the width direction of the encapsulation film 2 can be equal or unequal.

[0218] In one embodiment, referring to Figures 17 and 18, the cross-section of the receiving groove 203 is an inverted trapezoid. At the connecting corners of adjacent sidewalls of the receiving groove 203, a second chamfer 206 is provided corresponding to the first chamfer 102. The distance TL4 between the first chamfer 102 and the second chamfer 206 satisfies 2mm ≤ TL4 ≤ 100mm. Setting the cross-section of the receiving groove 203 as an inverted trapezoid, and providing a second chamfer 206 at the connecting corners of adjacent sidewalls of the receiving groove 203 corresponding to the first chamfer 102, can reduce stress concentration at the receiving groove 203. Further limiting the distance TL4 between the first chamfer 102 and the second chamfer 206 can ensure the heat-melting width of the encapsulation area 3, ensuring encapsulation quality. If the distance TL4 between the first chamfer 102 and the second chamfer 206 is less than 2mm, the heat-melting width of the encapsulation area 3 will be narrow, easily leading to battery encapsulation failure. If the distance TL4 between the first chamfer 102 and the second chamfer 206 is too large, it wastes material from the encapsulation film 2.

[0219] Furthermore, in one embodiment, referring to Figures 16 and 17, the second chamfer 206 is a rounded corner, and the radius R of the rounded corner satisfies 0.4mm ≤ R ≤ 6mm. Setting the second chamfer 206 as a rounded corner and limiting the radius range of the rounded corner can further improve the stability and space utilization of the encapsulation film 2 during the punching process. If the radius R of the rounded corner is too small, the encapsulation film 2 is prone to being subjected to large shear forces during punching, leading to the encapsulation film 2 breaking. If the radius R of the rounded corner is too large, the arc will interfere with the edge of the electrode assembly 1 and crush the electrode assembly 1, causing damage to the electrode assembly 1 and resulting in a short circuit.

[0220] Furthermore, in one embodiment, when 0.5mm ≤ H1 < 1mm, the radius R of the fillet satisfies 0.4mm ≤ R < 1mm.

[0221] When 1mm≤H1<5mm, the radius R of the fillet satisfies 1mm≤R<3mm.

[0222] When 5mm≤H1≤50mm, the radius R of the fillet satisfies 3mm≤R≤6mm.

[0223] Setting the radius R of the arc to correspond with the depth H1 of the receiving groove 203 can further improve the stability and space utilization of the encapsulation film 2 during the punching process.

[0224] For example, when H1 is 0.5mm, the radius R of the fillet can be 0.4mm, 0.5mm, or 0.9mm. When H1 is 3mm, the radius R of the fillet can be 1mm, 2mm, or 2.5mm. When H1 is 10mm, the radius R of the fillet can be 3mm, 4mm, or 6mm.

[0225] In one embodiment, as shown in Figure 16, the encapsulation film 2 has notches 207 at opposite ends of the fold line. By having notches 207 at opposite ends of the fold line, a chamfer can be formed after the encapsulation film 2 is folded, preventing the corners of the encapsulation film 2 from scratching workers and facilitating transportation.

[0226] In one embodiment, referring to Figure 18, the wall of the receiving groove 203 is inclined relative to the bottom of the groove, and the inclination angle θ satisfies 95°≤θ≤160°. By setting the groove wall of the receiving groove 203 to be inclined, it is easier to install and limit the electrode assembly 1, reduce the offset of the electrode assembly 1, thereby providing better support for the electrode assembly 1, ensuring that the encapsulation film 2 can uniformly cover the electrode assembly 1, and improving the encapsulation quality. If the inclination angle θ is too small, the encapsulation film 2 will be subjected to a large shear force during the punching process, and the heat-fused layer is prone to breakage and failure. If the inclination angle θ is too large, in order to avoid interference between the groove wall and the electrode assembly 1, a large clearance space needs to be reserved, resulting in wasted space and materials.

[0227] Of course, in other alternative implementations, the battery can also be in other shapes, such as a disc, an elliptical cylinder, etc. Correspondingly, the encapsulation film 2 and the electrode assembly 1 are adapted to each other.

[0228] The process parameters of the battery in this application embodiment are further described in detail below with reference to specific embodiments. In the following embodiments and comparative examples, the battery has a rectangular structure, the encapsulation film 2 is correspondingly square, and the fold line is the centerline of the length direction of the encapsulation film 2. The cross-section of the receiving groove 203 is an inverted trapezoid. It should be noted that these examples should not be construed as limiting the scope of protection claimed in this application.

[0229] Example T1:

[0230] The distance TL1 between adjacent edges of the two receiving grooves 203 is 1.2 mm, the depth H1 of the receiving groove 203 is 2 mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 12 mm. Therefore, TL1 / H1 = 0.6, which is the minimum value in this embodiment, and TL2 / H1 = 6. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 1 mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 1 mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 2 mm, the radius R of the rounded corner is 1 mm, and the tilt angle θ is 100°. The test verification results after battery production line testing are shown in Table 3.

[0231] Example T2:

[0232] The distance TL1 between adjacent edges of the two receiving grooves 203 is 2mm, the depth H1 of the receiving groove 203 is 2mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 10mm. Therefore, TL1 / H1 = 1 and TL2 / H1 = 5, which are the minimum values ​​in this embodiment. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 2mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 2mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 3mm, the radius R of the rounded corner is 2mm, and the tilt angle θ is 100°. The test verification results after battery production line testing are shown in Table 3.

[0233] Example T3:

[0234] The distance TL1 between adjacent edges of the two receiving grooves 203 is 10mm, the depth H1 of the receiving groove 203 is 5mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 100mm. Therefore, TL1 / H1 = 2, TL2 / H1 = 20. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 10mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 10mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 10mm, the radius R of the rounded corner is 6mm, which is the maximum value in this embodiment, and the tilt angle θ is 150°. The test verification results after battery production line testing are shown in Table 3.

[0235] Example T4:

[0236] The distance TL1 between adjacent edges of the two receiving grooves 203 is 10mm, the depth H1 of the receiving groove 203 is 5mm, and the distance TL2 between the side edges of the receiving groove 203 along the length direction of the encapsulation film 2 is 60mm. Therefore, TL1 / H1 = 2, TL2 / H1 = 12. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 10mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 10mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 10mm, the radius R of the rounded corner is 5mm, and the tilt angle θ is 95°, which are the minimum values ​​in this embodiment. The test verification results after battery production line testing are shown in Table 3.

[0237] Example T5:

[0238] The distance TL1 between adjacent edges of the two receiving grooves 203 is 40mm, the depth H1 of the receiving groove 203 is 10mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 60mm. Therefore, TL1 / H1 = 4, TL2 / H1 = 6. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 20mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 20mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 20mm, the radius R of the rounded corner is 5mm, and the tilt angle θ is 160°, which is the maximum value of this embodiment. The test verification results after battery production line testing are shown in Table 3.

[0239] Comparative Example T1:

[0240] The distance TL1 between adjacent edges of the two receiving grooves 203 is 1 mm, the depth H1 of the receiving groove 203 is 2 mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 12 mm. Therefore, TL1 / H1 = 0.5, which is less than 0.6, and TL2 / H1 = 6. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 1 mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 1 mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 2 mm, the radius R of the rounded corner is 1 mm, and the tilt angle θ is 95°. The test verification results after battery production line testing are shown in Table 3.

[0241] Comparative Example T2:

[0242] The distance TL1 between adjacent edges of the two receiving grooves 203 is 2mm, the depth H1 of the receiving groove 203 is 2mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 8mm. Therefore, TL1 / H1 = 1, TL2 / H1 = 4, which is less than 5. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 2mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 2mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 3mm, the radius R of the rounded corner is 2mm, and the tilt angle θ is 100°. The test verification results after battery production line testing are shown in Table 3.

[0243] Comparative Example T3:

[0244] The distance TL1 between adjacent edges of the two receiving grooves 203 is 5mm, the depth H1 of the receiving groove 203 is 2mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 12mm. Therefore, TL1 / H1 = 2.5, TL2 / H1 = 6. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 2mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 2mm, and the distance TL4 between the first chamfer 102 and the second chamfer 206 is 1mm, which is less than 2mm. The radius R of the fillet is 2mm, and the tilt angle θ is 100°. The test verification results after battery production line testing are shown in Table 3.

[0245] Comparative Example T4:

[0246] The distance TL1 between adjacent edges of the two receiving grooves 203 is 6 mm, the depth H1 of the receiving groove 203 is 0.6 mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 6 mm. Therefore, TL1 / H1 = 10, TL2 / H1 = 10. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 2 mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 2 mm, and the distance TL4 between the first chamfer 102 and the second chamfer 206 is 4 mm. The radius R of the fillet is 0.3 mm, which is less than 0.4 mm, and the tilt angle θ is 100°. The test verification results after battery production line testing are shown in Table 3.

[0247] Comparative Example T5:

[0248] The distance TL1 between adjacent edges of the two receiving grooves 203 is 10mm, the depth H1 of the receiving groove 203 is 5mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 100mm. Therefore, TL1 / H1 = 2, TL2 / H1 = 20. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 10mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 10mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 10mm, and the radius R of the rounded corner is 7mm, which is greater than 6mm. The tilt angle θ is 150°. The test verification results after battery production line testing are shown in Table 3.

[0249] Comparative Example T6:

[0250] The distance TL1 between adjacent edges of the two receiving grooves 203 is 10mm, the depth H1 of the receiving groove 203 is 5mm, and the distance TL2 between the two sides of the receiving groove 203 along the length direction of the encapsulation film 2 is 60mm. Therefore, TL1 / H1 = 2, TL2 / H1 = 12. The dimension TL3 of the first chamfer 102 along the length direction of the encapsulation film 2 is 10mm, the dimension TW1 of the first chamfer 102 along the width direction of the encapsulation film 2 is 10mm, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 10mm, the radius R of the rounded corner is 5mm, and the tilt angle θ is 90°, which is less than 95°. The test verification results after battery production line testing are shown in Table 3.

[0251] Table 3: Test Results

[0252] As shown in Table 3, in Examples T1 to T5, the following conditions are met: 1mm≤TL1≤50mm, 0.5mm≤H1≤50mm, 0.6≤TL1 / H1≤100, 2.5mm≤TL2≤100mm, 5≤TL2 / H1≤50, 1mm≤TL3≤50mm, 1mm≤TW1≤50mm, and 2mm≤TL4≤100mm. When 0.5mm≤H1<1mm, 0.4mm≤R<1mm; when 1mm≤H1<5mm, 1mm≤R<3mm; when 5mm≤H1≤50mm, 3mm≤R≤6mm; and 95°≤θ≤160°. Therefore, there are no abnormalities after encapsulation, the encapsulation quality is high, and materials are saved.

[0253] In comparative example T1, TL1 / H1 = 0.5, which is less than 0.6 and lower than the minimum value in the embodiments of this application. When the dent is punched, the encapsulation film 2 breaks, resulting in encapsulation failure.

[0254] In Comparative Example T2, TL2 / H1 = 4, which is less than 5 and lower than the minimum value in the embodiments of this application. During hot melting, the hot melt layer of the encapsulation area 3 shrinks, and the melt width is too narrow, resulting in sealing failure.

[0255] In Comparative Example T3, the distance TL4 between the first chamfer 102 and the second chamfer 206 is 1mm, which is less than 2mm and lower than the minimum value in the embodiments of this application. During hot melting, the weld width of the encapsulation area 3 is too narrow, resulting in sealing failure.

[0256] In Comparative Example T4, H1 = 0.6 mm, and the radius R of the rounded corner is 0.3 mm, which is less than 0.4 mm and lower than the minimum value in the embodiments of this application. When the dent is punched, the encapsulation film 2 breaks, resulting in encapsulation failure.

[0257] In Comparative Example T5, H1 = 5mm, and the radius R of the rounded corner is 7mm, which is greater than 6mm and exceeds the maximum value of the embodiment of this application. The arc interferes with the edge of the pole group 1 and crushes the pole group 1, causing damage to the pole group 1 and resulting in a short circuit.

[0258] In Comparative Example T6, the tilt angle θ = 90°, which is less than 95° and lower than the minimum value in the embodiments of this application. When the pit is punched, the encapsulation film 2 breaks, resulting in encapsulation failure.

[0259] In one embodiment, the encapsulation film 2 is divided into a first sub-encapsulation film 201 and a second sub-encapsulation film 202 by a fold line, and the first sub-encapsulation film 201 and the second sub-encapsulation film 202 extend concavely to form receiving grooves 203 for accommodating the electrode assembly 1. After the second sub-encapsulation film 202 is folded along the fold line, it is relatively attached to the first sub-encapsulation film 201, covering the electrode assembly 1 in the cavity formed by the two receiving grooves 203; the periphery of the first sub-encapsulation film 201 and the second sub-encapsulation film 202 are respectively provided with encapsulation areas 3 surrounding the electrode assembly 1.

[0260] The distance TL1 between adjacent edges of the two receiving grooves 203 and the depth H1 of the receiving groove 203 satisfy 0.6≤TL1 / H1≤100, where TL1 is 1mm~50mm and H1 is 0.5mm~50mm. The groove wall of the receiving groove 203 is inclined relative to the groove bottom, with an inclination angle θ satisfying 95°≤θ≤160°, so that the groove opening area is larger than the groove bottom area. In the height direction of the encapsulation film 2, the projected width H3 of the groove wall of the receiving groove 203 satisfies 0.1mm≤H3≤20mm, and 0.2≤H3 / H1≤0.8.

[0261] The receiving groove 203 has an inverted trapezoidal cross-section. Its bottom is connected to the groove wall via a first arc, with a radius R1 satisfying 0.3mm ≤ R1 ≤ 5mm. Adjacent groove walls are connected by a second arc, with a radius R2 satisfying 0.5mm ≤ R2 ≤ 5mm. The groove opening is connected to the top surface of the encapsulation film 2 via a third arc, with a radius R3 satisfying 0.5mm ≤ R3 ≤ 5mm. The distance X between the groove opening edge and the fold line of the receiving groove 203 satisfies 1mm + R3 ≤ X ≤ 30mm.

[0262] In the width direction of the battery, the width W1 of the electrode group 1 and the bottom width W2 of the receiving groove 203 satisfy 30mm≤W1≤200mm, 28mm≤W2≤250mm, and 0.8≤W1 / W2≤1.05; in the length direction of the battery, the length L1 of the electrode group 1 and the bottom length L2 of the receiving groove 203 satisfy 50mm≤L1≤400mm, 45mm≤L2≤500mm, and 0.8≤L1 / L2≤1.1.

[0263] The encapsulation film 2 has first rounded corners 204 at opposite ends of the fold line, with a radius SR1 satisfying 1mm ≤ SR1 ≤ 50mm; the encapsulation film 2 has second rounded corners 205 at its four corners, with a radius SR2 satisfying 1mm ≤ SR2 ≤ 50mm; in the width direction of the battery, the width W3 of the encapsulation area 3 satisfies 1mm ≤ W3 ≤ 50mm. The distance L3 between the edge of the receiving groove 203 and the edge of the first rounded corner 204 satisfies W3 + 0.5mm ≤ L3 ≤ 50mm; the distance L5 between the second rounded corner 205 and the edge of the receiving groove 203 satisfies 3mm ≤ L5 ≤ 50mm.

[0264] In addition, the four corners of the encapsulation film 2 are provided with a first chamfer 102, the length dimension TL3 of which satisfies 1mm≤TL3≤50mm, and the width dimension TW1 satisfies 1mm≤TW1≤50mm. At the connecting corners of adjacent sidewalls of the receiving groove 203, corresponding to the first chamfer 102, a second chamfer 206 is provided. The second chamfer 206 is a rounded corner with a radius R satisfying 0.4mm≤R≤6mm, and is categorized according to the depth H1 of the receiving groove: when 0.5mm≤H1<1mm, 0.4mm≤R<1mm; when 1mm≤H1<5mm, 1mm≤R<3mm; when 5mm≤H1≤50mm, 3mm≤R≤6mm. The distance TL4 between the first chamfer 102 and the second chamfer 206 satisfies 2mm≤TL4≤100mm.

[0265] According to an embodiment of this application, another aspect provides a battery pack, including a battery.

[0266] Since the battery pack includes a battery and has the same effect as a battery, it will not be elaborated further here.

[0267] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

A battery comprising: The pole assembly has a pole tab on one side; The encapsulation film is divided into a first sub-encapsulation film and a second sub-encapsulation film by a fold line. The first sub-encapsulation film and / or the second sub-encapsulation film extend concavely to form a receiving groove for accommodating the electrode assembly. The second sub-encapsulation film is folded along the fold line and is opposite to and attached to the first sub-encapsulation film to cover the electrode assembly. The periphery of the first sub-encapsulation film and the second sub-encapsulation film are respectively provided with an encapsulation area surrounding the electrode assembly. The battery according to claim 1, characterized in that, The first sub-encapsulation film extends concavely to form the receiving groove for accommodating the electrode assembly; the groove depth H1 of the receiving groove satisfies 0.1mm≤H1≤25mm; the thickness H2 of the encapsulation film satisfies 0.05mm≤H2≤0.5mm and 0.02≤H2 / H1≤0.

5. The battery according to claim 2, characterized in that, The bottom of the receiving groove is connected to the groove wall by a first arc, and the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm. The battery according to claim 3 is characterized in that, When 0.02≤H2 / H1<0.1, the radius R1 of the first arc satisfies 1mm≤R1≤5mm; When 0.1≤H2 / H1≤0.5, the radius R1 of the first arc satisfies 0.3mm≤R1≤5mm. The battery according to any one of claims 1 to 4 is characterized in that, The wall of the receiving tank is inclined relative to the bottom of the tank, so that the area of ​​the opening of the receiving tank is larger than the area of ​​the bottom of the tank. The battery according to claim 5, characterized in that, The projection width H3 of the groove wall of the receiving groove in the height direction of the encapsulation film satisfies the following conditions: 0.1mm≤H3≤20mm, 0.2≤H3 / H1≤0.

8. The battery according to claim 5, characterized in that, The cross-section of the receiving groove is an inverted trapezoid, and the adjacent groove walls are connected by a second circular arc. The radius R2 of the second circular arc satisfies 0.5mm≤R2≤5mm. The battery according to claim 5, characterized in that, The opening of the receiving groove is connected to the top surface of the encapsulation film through a third arc, and the radius R3 of the third arc satisfies 0.5mm≤R3≤5mm. The battery according to claim 8, characterized in that, When 0.02≤H2 / H1<0.1, the radius R3 of the third arc satisfies 1.5mm≤R3≤5mm; When 0.1≤H2 / H1≤0.5, the radius R3 of the third arc satisfies 0.5mm≤R3≤5mm. The battery according to claim 8, characterized in that, The distance X between the edge of the receiving groove and the fold line satisfies 1mm+R3≤X≤30mm. The battery according to claim 1, characterized in that, The wall of the receiving groove is inclined at an obtuse angle relative to the bottom of the groove, and the depth of the receiving groove is H1. In the width direction of the battery, the width W1 of the electrode assembly and the bottom width W2 of the receiving groove satisfy 30mm≤W1≤200mm, 28mm≤W2≤250mm, and 0.8≤W1 / W2≤1.

05. In the length direction of the battery, the length L1 of the electrode assembly and the bottom length L2 of the receiving groove satisfy 50mm≤L1≤400mm, 45mm≤L2≤500mm, and 0.8≤L1 / L2≤1.

1. The battery according to claim 11, characterized in that, The first sub-encapsulation film and the second sub-encapsulation film are respectively provided with a first rounded corner at the opposite ends of the fold line, and the radius SR1 of the first rounded corner satisfies 1mm≤SR1≤50mm. The battery according to claim 12, characterized in that, In the width direction of the battery, the width W3 of the encapsulation area satisfies 1mm≤W3≤50mm. The battery according to claim 13 is characterized in that, In the width direction of the battery, the distance L3 between the edge of the receiving groove and the edge of the first rounded corner satisfies W3+0.5mm≤L3≤50mm. The battery according to claim 11, characterized in that, When the thickness T of the battery is ≥ 20 mm, the first sub-encapsulation film and the second sub-encapsulation film extend concavely to form the receiving groove. The battery according to claim 11, characterized in that, When the receiving groove is formed by the recessed extension of the first sub-encapsulation film or the second sub-encapsulation film, the distance L4 between the side of the receiving groove near the fold line and the fold line and the depth H1 of the receiving groove satisfy 2mm≤L4≤30mm, 0.5mm≤H1≤50mm, and 0.2≤L4 / H1≤100. The battery according to any one of claims 11 to 16 is characterized in that, The encapsulation film is square-shaped, and has a second rounded corner at each of the four corners. The radius of the second rounded corner, SR2, satisfies 1mm≤SR2≤50mm. The battery according to claim 17, characterized in that, The distance L5 between the second fillet and the edge of the receiving groove satisfies 3mm≤L5≤50mm. The battery according to claim 1, characterized in that, The first sub-encapsulation film and the second sub-encapsulation film are respectively recessed to form the receiving groove for accommodating the electrode assembly; the distance TL1 between the adjacent edges of the two receiving grooves and the depth H1 of the receiving groove satisfy 0.6≤TL1 / H1≤100. The battery according to claim 19 is characterized in that, The distance TL1 between adjacent edges of the two receiving grooves satisfies 1mm≤TL1≤50mm, and the depth H1 of the receiving grooves satisfies 0.5mm≤H1≤50mm. The battery according to claim 20 is characterized in that, The distance TL2 between the side edges of the encapsulation film in the width direction and the side edges of the encapsulation film in the width direction satisfies 2.5mm≤TL2≤100mm and 5≤TL2 / H1≤50. The battery according to any one of claims 19 to 21 is characterized in that, The encapsulation film is square-shaped, with a first chamfer at each of the four corners. The dimension TL3 of the first chamfer along the length of the encapsulation film satisfies the condition 1mm ≤ TL3 ≤ 50mm. The dimension TW1 of the first chamfer in the width direction of the encapsulation film satisfies 1mm≤TW1≤50mm. The battery according to claim 22 is characterized in that, The cross-section of the receiving groove is an inverted trapezoid. At the connecting corners of adjacent sidewalls of the receiving groove, a second chamfer is provided corresponding to the first chamfer. The distance TL4 between the first chamfer and the second chamfer satisfies 2mm≤TL4≤100mm. The battery according to claim 23 is characterized in that, The second chamfer is a rounded corner, and the radius R of the rounded corner satisfies 0.4mm≤R≤6mm. The battery according to claim 24 is characterized in that, When 0.5mm≤H1<1mm, the radius R of the fillet satisfies 0.4mm≤R<1mm; When 1mm≤H1<5mm, the radius R of the fillet satisfies 1mm≤R<3mm; When 5mm≤H1≤50mm, the radius R of the fillet satisfies 3mm≤R≤6mm. The battery according to claim 22 is characterized in that, The encapsulation film has notches at both ends of the fold line. The battery according to any one of claims 19 to 21 is characterized in that, The wall of the receiving tank is inclined relative to the bottom of the tank, and the inclination angle θ satisfies 95°≤θ≤160°. A battery pack, characterized in that, include: The battery according to any one of claims 1 to 27.

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