Batteries and battery packs

Abstract

This invention relates to the field of battery technology and discloses a battery and a battery pack. The battery includes: an electrode assembly with tabs; a first encapsulation film and a second encapsulation film for wrapping the electrode assembly; the first and second encapsulation films are disposed opposite each other and each has an encapsulation area surrounding the electrode assembly; in the encapsulation area, a first heat-fused layer is respectively provided on the opposite side of the first and second encapsulation films; the tabs have an insulating layer, and a second heat-fused layer is provided corresponding to the first heat-fused layer; the tabs are fixed to the first and second encapsulation films by heat-fused first and second heat-fused layers, forming a third heat-fused layer. The thicknesses H1 of the first heat-fused layer, H2 of the second heat-fused layer, and H3 of the third heat-fused layer satisfy 0.3 ≤ H3 / H1 ≤ 0.75 and 0.36 ≤ H3 / H2 ≤ 0.7. This invention improves the battery encapsulation quality and reduces material waste by limiting the parameters of the heat-fused layers of the tabs and encapsulation films.

Description

Technical Field

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

[0002] A battery mainly consists of tabs, electrode assembly, and encapsulation film. The encapsulation film encapsulates the electrode assembly and tabs, and then seals them through hot pressing. However, in the current battery encapsulation process, it is difficult to effectively balance the process parameters of the encapsulation film and the electrode assembly. If the process parameters of hot-melt encapsulation are too large, it is easy to waste encapsulation material; if the process parameters of hot-melt encapsulation are too small, it is easy to cause battery encapsulation failure. Summary of the Invention

[0003] In view of this, the present invention provides a battery and a battery pack to solve the problem that when encapsulating electrode groups in existing batteries, it is difficult to effectively balance the process parameters of the encapsulation film and the electrode group, resulting in easy encapsulation failure and waste of encapsulation materials.

[0004] In a first aspect, the present invention provides a battery comprising:

[0005] The pole group is equipped with pole tabs;

[0006] A first encapsulation film and a second encapsulation film are used to wrap the electrode group. The first encapsulation film and the second encapsulation film are arranged opposite to each other and are provided with an encapsulation area around the electrode group. In the encapsulation area, the first encapsulation film and the second encapsulation film are respectively provided with a first hot melt layer on the opposite side.

[0007] The tabs are provided with insulating layers on opposite sides. The insulating layers are provided with a second hot-melt layer corresponding to the first hot-melt layer. The tabs are fixed to the first encapsulation film and the second encapsulation film respectively by hot-melting the first hot-melt layer and the second hot-melt layer, and a third hot-melt layer is formed. The thickness H1 of the first hot-melt layer, the thickness H2 of the second hot-melt layer and the thickness H3 of the third hot-melt layer satisfy 0.3≤H3 / H1≤0.75 and 0.36≤H3 / H2≤0.7.

[0008] Beneficial Effects: In the battery assembly of this invention, the electrode assembly with welded tabs is first placed between the first and second encapsulation films, with the tabs extending beyond them. The encapsulation area is then heat-sealed to fix the first and second encapsulation films. A third heat-melt layer is formed by the second heat-melt layer of the insulating layer on the tab and the first heat-melt layer of the encapsulation film, thus bonding the tabs to both the first and second encapsulation films. The structure is simple and convenient to use. By defining the proportional relationship between the first, second, and third heat-melt layers, the bonding force between the tabs and the first and second encapsulation films can be guaranteed, preventing the tabs from detaching from the first and / or second encapsulation films, thereby ensuring the effectiveness of the encapsulation. Simultaneously, it saves materials and improves space utilization.

[0009] In one optional embodiment, the thickness H1 of the first hot melt layer satisfies 0.06mm≤H1≤0.8mm.

[0010] Beneficial effects: By limiting the thickness range of the first hot melt layer, it is possible to ensure that the first encapsulation film, the second encapsulation film and the electrode tab are fully fused. If the thickness of the first hot melt layer is too large, the hot melt time will be too long or the temperature will be too high, which will easily damage the first encapsulation film, the second encapsulation film and the internal electrode assembly. If the thickness of the first hot melt layer is too small, it will easily crack.

[0011] In one optional embodiment, the thickness H2 of the second hot melt layer satisfies 0.05mm ≤ H2 ≤ 0.3mm.

[0012] Beneficial effects: By limiting the thickness range of the second hot melt layer, the insulation between the tab and the first and second encapsulation films can be ensured, preventing short circuits. If the thickness of the second hot melt layer is too small, the hot melt will be insufficient and the adhesion will be weak. If the thickness of the second hot melt layer is too large, the hot melt will be more difficult and the production efficiency will be affected.

[0013] In one optional embodiment, the thickness H3 of the third hot melt layer satisfies 0.018mm≤H3≤0.6mm.

[0014] Beneficial effects: By limiting the thickness range of the third hot melt layer, it is possible to ensure a tight bond between the tab and the first and second encapsulation films, preventing the battery from falling off or being damaged due to the force on the tab during charging and discharging, while also avoiding excessive or insufficient overflow of the third hot melt layer, which could lead to encapsulation failure.

[0015] In one optional implementation, the width W1 of the third hot melt layer satisfies 1mm≤W1≤20mm.

[0016] Beneficial effects: By limiting the width range of the third hot melt layer, it is possible to ensure sufficient adhesion between the tab and the first and second encapsulation films, forming a reliable sealed and fixed area. If the width of the third hot melt layer is too small, the battery will expand cyclically during use, causing the third hot melt layer to peel off under force, resulting in seal failure. If the width of the third hot melt layer is too large, it will waste materials and increase the difficulty of hot melting.

[0017] In one alternative embodiment, in the length direction of the electrode assembly, the distance g between the outer edge of the third hot melt layer and the outer edge of the first encapsulation film or the second encapsulation film satisfies 0.5mm≤g≤15mm.

[0018] Beneficial effects: If the spacing g is too small, adhesive overflow is likely to occur at the outer edge of the encapsulation film during hot melting, causing the third hot melt layer to be extruded, piled up, and bulge. When the tab is swung and pulled, the stress in the bulging material area is too high, making it prone to cracking. This results in the metal plate of the tab being exposed and overlapping with the aluminum foil layer of the encapsulation film, causing a short circuit. If the spacing g is too large, the unfixed flange of the encapsulation film and the tab is prone to lifting, and the lifted part is prone to overlapping, causing a short circuit.

[0019] In one optional embodiment, the encapsulation region includes side encapsulation regions located on opposite sides in the width direction of the electrode group and end encapsulation regions located at opposite ends in the length direction of the electrode group. The opposite ends of the side encapsulation regions and the opposite ends of the end encapsulation regions respectively intersect and overlap to form an overlapping area.

[0020] Beneficial effects: By intersecting the ends of the side packaging area and the end packaging area to form an overlapping area, it can ensure that there is no gap at the junction of the side packaging area and the end packaging area, improve the sealing effect of the packaging area, and also improve the overall strength of the packaging area, preventing the battery from cracking due to internal pressure changes or external forces during charging and discharging.

[0021] In one optional embodiment, in the length direction of the electrode group, the size L1 of the overlapping area satisfies 0.5mm≤L1≤20mm, and in the width direction of the electrode group, the size L2 of the overlapping area satisfies 0.5mm≤L2≤20mm.

[0022] Beneficial effects: If the overlapping area is too small in the length and / or width direction of the electrode group, the sealing performance will be poor and the battery will be easy to detach under force during use. If the overlapping area is too large in the length and / or width direction of the electrode group, it will waste materials and space.

[0023] In one optional embodiment, the distance L3 between the end of the side encapsulation area and the edge of the first encapsulation film or the second encapsulation film in the length direction satisfies 0.3mm≤L3≤20mm;

[0024] And / or, the distance L4 between the end of the end packaging area and the edge of the first packaging film or the second packaging film in the width direction satisfies 0.3mm≤L4≤20mm.

[0025] Beneficial effects: If the spacing L3 and / or L4 is too small, the third hot melt layer is prone to flow and extrusion during hot pressing, resulting in glue overflow, which affects the overall size design of the battery. If the spacing L3 and / or L4 is too large, it will waste materials and space.

[0026] Secondly, the present invention also provides a battery pack comprising: the battery described above.

[0027] 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

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A magnified view of a portion of point B in the middle;

[0031] Figure 3 for Figure 1 The cross-sectional view of the AA battery shown;

[0032] Figure 4 for Figure 3 A magnified view of a portion of point C in the middle;

[0033] Figure 5 for Figure 4 A magnified view of a portion of point D.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Electrode assembly; 101. Electrode tab; 2. First encapsulation film; 3. Second encapsulation film; 4. Encapsulation area; 401. Side encapsulation area; 402. End encapsulation area; 403. Overlapping area; 5. First hot melt layer; 6. Insulating layer; 601. Second hot melt layer; 7. Third hot melt layer. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0038] According to an embodiment of the present invention, a battery is provided, mainly comprising: an electrode assembly 1, a first encapsulation film 2, and a second encapsulation film 3. The electrode assembly 1 is provided with tabs 101. The first encapsulation film 2 and the second encapsulation film 3 are used to wrap around the electrode assembly 1. The first encapsulation film 2 and the second encapsulation film 3 are disposed opposite to each other and are each provided with an encapsulation area 4 surrounding the electrode assembly 1. In the encapsulation area 4, a first heat-melting layer 5 is provided on the opposite side of the first encapsulation film 2 and the second encapsulation film 3, respectively.

[0039] Furthermore, the tab 101 is provided with an insulating layer 6 on each of its two opposite sides. The insulating layer 6 is provided with a second hot melt layer 601 corresponding to the first hot melt layer 5. By hot melting the first hot melt layer 5 and the second hot melt layer 601, the tab 101 is fixed to the first encapsulation film 2 and the second encapsulation film 3 respectively, and a third hot melt layer 7 is formed. The thickness H1 of the first hot melt layer 5, the thickness H2 of the second hot melt layer 601 and the thickness H3 of the third hot melt layer 7 satisfy 0.3≤H3 / H1≤0.75 and 0.36≤H3 / H2≤0.7.

[0040] Therefore, the battery provided in this embodiment of the invention, during assembly, first places the electrode assembly 1 after welding the tabs 101 between the first encapsulation film 2 and the second encapsulation film 3, with the tabs 101 extending beyond the first and second encapsulation films 2 and 3. The encapsulation area 4 is then heat-sealed to fix the first and second encapsulation films 2 and 3. A third heat-melt layer 7 is formed by the second heat-melt layer 601 of the insulating layer 6 on the heat-melt tab 101 and the first heat-melt layer 5 of the encapsulation film, thus bonding and fixing the tabs 101 to the first and second encapsulation films 2 and 3 respectively. The structure is simple and convenient to use. By limiting the proportional relationship between the first heat-melt layer 5, the second heat-melt layer 601, and the third heat-melt layer 7, the bonding force between the tabs 101 and the first and second encapsulation films 2 and 3 can be guaranteed, preventing the tabs 101 from detaching from the first and / or second encapsulation films 2 and 3, thereby ensuring the effectiveness of the encapsulation. At the same time, it can also save materials and improve space utilization.

[0041] Specifically, please refer to Figure 1 and Figure 3The electrode tab 101 includes a positive electrode tab and a negative electrode tab. The positive electrode tab is located at one end along the length of the electrode group 1, and the negative electrode tab is located at the other end along the length of the electrode group 1, or the positive and negative electrode tabs are located on the same side of the electrode group 1. Please refer to the length direction of the electrode group 1 for details. Figure 1 For the arrow L in the diagram, please refer to the width direction of pole group 1. Figure 1 Arrow W in the diagram. A first PP layer is correspondingly provided on the first encapsulation film 2 and the second encapsulation film 3, serving as the first hot-melt layer 5. PP is polypropylene. The insulating layer 6 can be made of tab adhesive, with a second PP layer on the tab adhesive, serving as the second hot-melt layer 601. An aluminum foil layer is also provided on the first encapsulation film 2 and the second encapsulation film 3.

[0042] It should be noted that the ratio H3 / H1, where the thickness H3 of the third hot-melt layer 7 is to the thickness H1 of the first hot-melt layer 5, determines the bonding strength between the first PP layer and the second PP layer. If the ratio H3 / H1 is less than 0.3, the melting depth of the third hot-melt layer 7 is insufficient, and the two layers are prone to peeling off during battery use, leading to the separation of the tab 101 from the encapsulation film, ultimately resulting in encapsulation failure and sealing failure. For example, H3 / H1 can be 0.3, 0.4, 0.5, 0.75, etc.

[0043] Furthermore, if the H3 / H2 ratio is greater than 0.7, it will lead to over-melting, affecting the bonding strength between the first PP layer and the aluminum foil layer. During battery use, the two layers are prone to peeling. Under stress, the peeling area expands and extends to electrode group 1. The peeled first PP layer will show damage or thinning, resulting in insufficient insulation withstand voltage, ultimately leading to internal short circuits or abnormal resistance within the battery. Examples of suitable H3 / H2 ratios include 0.36, 0.5, 0.6, and 0.7.

[0044] It should be noted that the embodiments of the present invention do not limit the specific structure of the first encapsulation film 2 and the second encapsulation film 3 covering the electrode assembly 1. For example, the first encapsulation film 2 is provided with a receiving groove for mounting the electrode assembly 1, and the electrode assembly 1 after welding the electrode tab 101 is placed in the receiving groove. Alternatively, receiving grooves for mounting the electrode assembly 1 are respectively provided on the first encapsulation film 2 and the second encapsulation film 3. Then, the heat-melting areas around the first encapsulation film 2 and the second encapsulation film 3 are heat-melted and plastic-sealed.

[0045] In one embodiment, see Figure 1 The battery can be a rectangular structure, and the first encapsulation film 2 and the second encapsulation film 3 are respectively square.

[0046] Of course, in other alternative embodiments, the battery can also be in other shapes, such as a disc, an elliptical cylinder, etc. Correspondingly, the first encapsulation film 2, the second encapsulation film 3, and the electrode assembly 1 are adapted and configured.

[0047] It should be noted that the materials of the first encapsulation film 2 and the second encapsulation film 3 in this embodiment of the invention can be selected according to actual conditions. For example, the first encapsulation film 2 and the second encapsulation film 3 can be aluminum-plastic films. The thickness of the first encapsulation film 2 and the thickness of the second encapsulation film 3 can be selected to be equal or unequal according to actual conditions.

[0048] In one embodiment, see Figure 4 and Figure 5 The thickness H1 of the first hot-melt layer 5 satisfies 0.06mm ≤ H1 ≤ 0.8mm. For example, H1 can be 0.06mm, 0.1mm, 0.5mm, 0.8mm, etc. By limiting the thickness range of the first hot-melt layer 5, sufficient fusion between the first encapsulation film 2, the second encapsulation film 3, and the electrode 101 can be ensured. If the thickness of the first hot-melt layer 5 is too large, the hot-melt time will be too long or the temperature will be too high, which may easily damage the first encapsulation film 2, the second encapsulation film 3, and the internal electrode assembly 1. If the thickness of the first hot-melt layer 5 is too small, it is prone to cracking.

[0049] Further, in one embodiment, please refer to Figure 4 and Figure 5 The thickness H2 of the second hot-melt layer 601 satisfies 0.05mm ≤ H2 ≤ 0.3mm. For example, H2 can be 0.05mm, 0.1mm, 0.2mm, 0.3mm, etc. By limiting the thickness range of the second hot-melt layer 601, the insulation between the tab 101 and the first encapsulation film 2 and the second encapsulation film 3 can be ensured, preventing short circuits. If the thickness of the second hot-melt layer 601 is too small, the hot-melt process will be insufficient, resulting in weak adhesion. If the thickness of the second hot-melt layer 601 is too large, the hot-melt process will be more difficult, affecting production efficiency.

[0050] Furthermore, in one embodiment, please refer to Figure 4 and Figure 5 The thickness H3 of the third hot-melt layer 7 satisfies 0.018mm ≤ H3 ≤ 0.6mm. For example, H3 can be 0.018mm, 0.1mm, 0.5mm, 0.6mm, etc. By limiting the thickness range of the third hot-melt layer 7, a tight bond between the tab 101 and the first encapsulation film 2 and the second encapsulation film 3 can be ensured, preventing the tab 101 from falling off or being damaged due to force during charging and discharging of the battery. At the same time, it avoids excessive overflow or insufficient application of the third hot-melt layer 7, which could lead to encapsulation failure.

[0051] In one embodiment, see Figure 4The width W1 of the third hot-melt layer 7 satisfies 1mm ≤ W1 ≤ 20mm. For example, W1 can be 1mm, 2mm, 5mm, 20mm, etc. By limiting the width range of the third hot-melt layer 7, sufficient adhesion between the tab 101 and the first encapsulation film 2 and the second encapsulation film 3 can be ensured, forming a reliable sealed and fixed area. If the width of the third hot-melt layer 7 is less than 1mm, the battery will expand cyclically during use, causing the third hot-melt layer 7 to peel off under force, resulting in seal failure. If the width of the third hot-melt layer 7 is greater than 20mm, it wastes material and increases the difficulty of hot-melting.

[0052] In one embodiment, see Figure 4 and Figure 5 In the length direction of electrode group 1, the distance g between the outer edge of the third hot melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 satisfies 0.5mm ≤ g ≤ 15mm. For example, the distance g can be 0.5mm, 1mm, 5mm, 15mm, etc. The outer edges of the first encapsulation film 2 and the second encapsulation film 3 can be aligned. If the distance g is too small, adhesive overflow is likely to occur at the outer edge of the encapsulation film during hot melting, causing the third hot melt layer 7 to be extruded, piled up, and bulged. When the electrode tab 101 swings and pulls, the stress in the bulging material area is too great, which can easily cause cracking, resulting in the metal plate of the electrode tab 101 being exposed and overlapping with the aluminum foil layer of the encapsulation film, causing a short circuit. If the distance g is too large, the unfixed flange of the encapsulation film and the electrode tab 101 is likely to lift up, and the lifted part is likely to overlap, causing a short circuit.

[0053] In one embodiment, see Figure 1 and Figure 2 The encapsulation area 4 includes side encapsulation areas 401 located on opposite sides in the width direction of the electrode group 1 and end encapsulation areas 402 located at opposite ends in the length direction of the electrode group 1. The opposite ends of the side encapsulation areas 401 and the opposite ends of the end encapsulation areas 402 respectively intersect and overlap to form an overlap area 403. By intersecting the ends of the side encapsulation areas 401 and the end encapsulation areas 402 to form the overlap area 403, it can ensure that there is no gap at the junction of the side encapsulation areas 401 and the end encapsulation areas 402, thereby improving the sealing effect of the encapsulation area 4. In addition, it can also improve the overall strength of the encapsulation area 4 and prevent the battery from cracking due to internal pressure changes or external forces during charging and discharging.

[0054] Specifically, the end encapsulation area 402 is first heat-sealed, and then the side encapsulation area 401 is heat-sealed.

[0055] Further, in one embodiment, please refer to Figure 2In the length direction of electrode group 1, the dimension L1 of the overlapping area 403 satisfies 0.5mm ≤ L1 ≤ 20mm, and in the width direction of electrode group 1, the dimension L2 of the overlapping area 403 satisfies 0.5mm ≤ L2 ≤ 20mm. For example, L1 can be 0.5mm, 1mm, 5mm, 20mm, etc., and L2 can be 0.5mm, 1mm, 5mm, 20mm, etc. If L1 and / or L2 are less than 0.5mm, the sealing performance is poor, and the battery is prone to detachment under stress during use. If L1 and / or L2 are greater than 20mm, it wastes material and space.

[0056] Further, in one embodiment, please refer to Figure 2 The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction satisfies 0.3mm≤L3≤20mm.

[0057] And / or, the distance L4 between the end of the end packaging area 402 and the edge of the first packaging film 2 or the second packaging film 3 in the width direction satisfies 0.3mm≤L4≤20mm.

[0058] It should be noted that if the spacing L3 and / or L4 is less than 0.3mm, the third hot-melt layer 7 is prone to flow and extrusion during hot pressing, resulting in excess adhesive and affecting the overall size design of the battery. If the spacing L3 and / or L4 is greater than 20mm, it wastes material and space. For example, L3 can be 0.3mm, 1mm, 5mm, 20mm, etc., and L4 can be 0.3mm, 1mm, 5mm, 20mm, etc.

[0059] The process parameters of the battery according to the embodiments of the present invention are further described in detail below with reference to specific examples. These examples should not be construed as limiting the scope of protection claimed by the present invention. The dimensional parameters of the first encapsulation film 2 and the second encapsulation film 3 are consistent in the various embodiments and comparative examples described below.

[0060] Example 1:

[0061] The thickness H1 of the first hot-melt layer 5 is 0.06 mm, the thickness H2 of the second hot-melt layer 601 is 0.05 mm, and the thickness H3 of the third hot-melt layer 7 is 0.018 mm. Therefore, H3 / H1 = 0.3 and H3 / H2 = 0.36. At this point, both H3 / H1 and H3 / H2 are at their minimum values. The width W1 of the third hot-melt layer 7 is 5 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 1 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 1 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 1 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.5 mm. The battery production line test verification results are shown in Table 1.

[0062] Example 2:

[0063] The thickness H1 of the first hot-melt layer 5 is 0.28 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.21 mm. Therefore, H3 / H1 = 0.75, and H3 / H2 = 0.7. At this point, H3 / H2 is at its maximum value. The width W1 of the third hot-melt layer 7 is 10 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 5 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 0.5 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 0.5 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.3 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.3 mm.

[0064] Example 3:

[0065] The thickness H1 of the first hot-melt layer 5 is 0.27 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.67 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 1.2 mm, which is close to the minimum value. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 5 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 2 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 2 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 1 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 1 mm.

[0066] Example 4:

[0067] The thickness H1 of the first hot-melt layer 5 is 0.27 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.67 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 20 mm, which is the maximum value. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 5 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 20 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 20 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 20 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 20 mm.

[0068] Example 5:

[0069] The thickness H1 of the first hot-melt layer 5 is 0.3 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.6 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 5 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 0.5 mm. At this time, g is the minimum value. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 1 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 1 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.5 mm.

[0070] Example 6:

[0071] The thickness H1 of the first hot-melt layer 5 is 0.3 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.6 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 5 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 15 mm. At this time, g is at its maximum value. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 10 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 10 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 5 mm.

[0072] Comparative Example 1:

[0073] The thickness H1 of the first hot-melt layer 5 is 0.09 mm, the thickness H2 of the second hot-melt layer 601 is 0.05 mm, and the thickness H3 of the third hot-melt layer 7 is 0.018 mm. Therefore, H3 / H1 = 0.2 and H3 / H2 = 0.36. In this case, H3 / H1 is less than 0.3. The width W1 of the third hot-melt layer 7 is 5 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 1 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 1 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 2 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.5 mm. The test verification results from the battery production line are shown in Table 1.

[0074] Comparative Example 2:

[0075] The thickness H1 of the first hot-melt layer 5 is 0.64 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.48 mm. Therefore, H3 / H1 = 0.75 and H3 / H2 = 1.6. In this case, H3 / H2 is greater than 0.7. The width W1 of the third hot-melt layer 7 is 5 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 1 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 2 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 2 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 1 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 1 mm. The battery production line test verification results are shown in Table 1.

[0076] Comparative Example 3:

[0077] The thickness H1 of the first hot-melt layer 5 is 0.3 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.6 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 0.8 mm. In this case, W1 is less than 1 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 10 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 10 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 10 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 5 mm.

[0078] Comparative Example 4:

[0079] The thickness H1 of the first hot-melt layer 5 is 0.27 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.67, and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 10 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 0.4 mm. In this case, g is less than 0.5 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 5 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 5 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 5 mm.

[0080] Comparative Example 5:

[0081] The thickness H1 of the first hot-melt layer 5 is 0.3 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.6 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 2 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 1 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 0.4 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 0.4 mm. At this time, both L1 and L2 are less than 0.5 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.5 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.5 mm.

[0082] Comparative Example 6:

[0083] The thickness H1 of the first hot-melt layer 5 is 0.3 mm, the thickness H2 of the second hot-melt layer 601 is 0.3 mm, and the thickness H3 of the third hot-melt layer 7 is 0.18 mm. Therefore, H3 / H1 = 0.6 and H3 / H2 = 0.6. The width W1 of the third hot-melt layer 7 is 2 mm. The distance g between the outer edge of the third hot-melt layer 7 and the outer edge of the first encapsulation film 2 or the second encapsulation film 3 is 1 mm. In the length direction of the electrode group 1, the dimension L1 of the overlapping area 403 is 1 mm, and in the width direction of the electrode group 1, the dimension L2 of the overlapping area 403 is 1 mm. The distance L3 between the end of the side encapsulation area 401 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the length direction is 0.2 mm. The distance L4 between the end of the end encapsulation area 402 and the edge of the first encapsulation film 2 or the second encapsulation film 3 in the width direction is 0.2 mm. At this time, both L1 and L2 are less than 0.3 mm.

[0084] Table 1: Test Results

[0085]

[0086] As shown in Table 1, in Examples 1 to 6, the following conditions are met: 0.06mm≤H1≤0.8mm, 0.05mm≤H2≤0.3mm, 0.018mm≤H3≤0.6mm, 0.3≤H3 / H1≤0.75, 0.36≤H3 / H2≤0.7, 1mm≤W1≤20mm, 0.5mm≤g≤15mm, 0.5mm≤L1≤20mm, 0.5mm≤L2≤20mm, 0.3mm≤L3≤20mm, and 0.3mm≤L4≤20mm. Therefore, the battery assembly requirements can be met while saving materials.

[0087] In Comparative Example 1, H3 / H1 is less than 0.3, which is lower than the lower limit value of the embodiment of the present invention. The melting depth of the third hot melt layer 7 is insufficient, which affects the bonding force between the first PP layer and the second PP layer. During use, the first PP layer and the second PP layer peel off, that is, the tab 101 peels off from the encapsulation film, resulting in encapsulation failure.

[0088] In Comparative Example 2, H3 / H2 is greater than 0.7, exceeding the upper limit of the embodiment of the present invention, resulting in over-melting. This affects the bonding force between the first PP layer and the aluminum foil layer. During use, the first PP layer peels off from the aluminum foil layer. After the battery is subjected to force, the peeling area expands and extends to the electrode assembly 1. The peeled first PP layer has a damaged or thinned area, resulting in insufficient insulation withstand voltage strength, which ultimately leads to an internal short circuit or abnormal resistance in the battery.

[0089] In Comparative Example 3, W1 is less than 1 mm, which is lower than the lower limit value of the embodiment of the present invention. During the use of the battery, it expands cyclically, causing the third hot melt layer 7 to peel off under force, and the tab 101 falls off the encapsulation film, resulting in encapsulation failure.

[0090] In Comparative Example 4, g is less than 0.5 mm, which is lower than the lower limit value of the embodiment of the present invention. When the hot melt is applied, the glue overflows at the outer edge of the encapsulation film, causing the third hot melt layer 7 to be extruded, piled up and bulged. When the tab 101 swings and pulls, the bulging material pile area cracks, the metal plate of the tab 101 is exposed and short-circuits with the aluminum foil layer of the encapsulation film.

[0091] In Comparative Example 5, L1 and L2 are less than 0.5 mm, which is lower than the lower limit value of the embodiment of the present invention. During use, the battery is subjected to force and separates from the first encapsulation film 2 and the second encapsulation film 3.

[0092] In Comparative Example 6, L3 and L4 are less than 0.3 mm, which is lower than the lower limit value of the embodiment of the present invention. During hot pressing, the third hot melt layer 7 flows and is extruded, resulting in glue overflow.

[0093] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, comprising: a battery.

[0094] Since the battery pack includes a battery and has the same effect as a battery, it will not be elaborated further here.

[0095] Although embodiments of the invention 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 the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, include: The pole group is equipped with pole tabs; A first encapsulation film and a second encapsulation film are used to wrap the electrode group. The first encapsulation film and the second encapsulation film are arranged opposite to each other and are provided with an encapsulation area around the electrode group. In the encapsulation area, the first encapsulation film and the second encapsulation film are respectively provided with a first hot melt layer on the opposite side. The tabs are provided with insulating layers on opposite sides. The insulating layers are provided with a second hot-melt layer corresponding to the first hot-melt layer. The tabs are fixed to the first encapsulation film and the second encapsulation film respectively by hot-melting the first hot-melt layer and the second hot-melt layer, and a third hot-melt layer is formed. The thickness H1 of the first hot-melt layer, the thickness H2 of the second hot-melt layer and the thickness H3 of the third hot-melt layer satisfy 0.3≤H3 / H1≤0.75 and 0.36≤H3 / H2≤0.

7. The width W1 of the third hot melt layer satisfies 1 mm ≤ W1 ≤ 20 mm.

2. The battery according to claim 1, characterized in that, The thickness H1 of the first hot melt layer satisfies 0.06 mm ≤ H1 ≤ 0.8 mm.

3. The battery according to claim 2, characterized in that, The thickness H2 of the second hot melt layer satisfies 0.05 mm ≤ H2 ≤ 0.3 mm.

4. The battery according to claim 3, characterized in that, The thickness H3 of the third hot melt layer satisfies 0.018 mm ≤ H3 ≤ 0.6 mm.

5. The battery according to any one of claims 1 to 4, characterized in that, In the length direction of the electrode group, the distance g between the outer edge of the third hot melt layer and the outer edge of the first encapsulation film or the second encapsulation film satisfies 0.5 mm ≤ g ≤ 15 mm.

6. The battery according to any one of claims 1 to 4, characterized in that, The encapsulation area includes side encapsulation areas located on opposite sides in the width direction of the electrode group and end encapsulation areas located at opposite ends in the length direction of the electrode group. The opposite ends of the side encapsulation areas and the opposite ends of the end encapsulation areas respectively intersect and overlap to form an overlapping area.

7. The battery according to claim 6, characterized in that, In the length direction of the electrode group, the size L1 of the overlapping area satisfies 0.5 mm ≤ L1 ≤ 20 mm, and in the width direction of the electrode group, the size L2 of the overlapping area satisfies 0.5 mm ≤ L2 ≤ 20 mm.

8. The battery according to claim 7, characterized in that, The distance L3 between the end of the side encapsulation area and the edge of the first or second encapsulation film along its length direction satisfies 0.3 mm ≤ L3 ≤ 20 mm; And / or, the distance L4 between the end of the end packaging area and the edge of the first packaging film or the second packaging film in the width direction satisfies 0.3 mm ≤ L4 ≤ 20 mm.

9. A battery pack, characterized in that, include: The battery according to any one of claims 1 to 8.

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