Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment, the battery cell comprises a shell, an electrode assembly and insulating gummed paper, and the electrode assembly comprises a first surface and a second surface opposite to each other along the thickness direction of the electrode assembly, and a third surface and a fourth surface opposite to each other along the width direction of the electrode assembly. And the positive pole lug and the negative pole lug of the electrode assembly are arranged at the same end or two ends of the electrode assembly in the length direction. The width of the electrode assembly is less than or equal to 40 mm. The insulating gummed paper comprises a first part, a second part, a third part, a fourth part and a fifth part which are integrally formed and sequentially connected, the first part is attached to the first surface, the second part is attached to the third surface, the third part is attached to the second surface, the fourth part is attached to the fourth surface, and the fifth part is attached to the first surface. The insulating gummed paper occupies a small space in the thickness direction of the electrode assembly, so that the utilization rate of the internal space of the shell in the thickness direction of the electrode assembly is improved, and the energy density of the battery cell is improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more particularly, to an electric core and an electrical device using the same. Background Art

[0002] With the rapid development of electronic information technology, various electronic devices are also developing towards the direction of intelligence and multi-functionality, and the requirement for the energy density of batteries is getting higher and higher.

[0003] Currently, a bottom adhesive is provided between the bottom surface of the electrode assembly and the outer shell for fixing the electrode assembly and the outer shell. A side adhesive is provided between the side surface of the electrode assembly and the outer shell for protecting the electrode assembly. A part of the side adhesive extends to the bottom surface of the electrode assembly and overlaps with the bottom adhesive, affecting the utilization rate of the internal space of the outer shell in the thickness direction of the electrode assembly, and further affecting the energy density of the electric core; or, currently, there is a gap between the bottom adhesive and the side adhesive on the bottom surface of the electrode assembly, and a part of the negative electrode tab located at the bottom of the electrode assembly is exposed, so that when the electric core is stressed, the negative electrode tab is easily stressed and the negative current collector is torn. Summary of the Invention

[0004] The present application provides an electric core and an electrical device using the same, which can at least solve one of the above technical problems.

[0005] In a first aspect, the present application provides an electric core, which includes an outer shell, an electrode assembly, and an insulating adhesive tape. The electrode assembly is disposed inside the outer shell. The electrode assembly includes a first surface and a second surface opposite to each other in its thickness direction, and a third surface and a fourth surface opposite to each other in its width direction. The electrode assembly includes a positive electrode tab and a negative electrode tab. The positive electrode tab and the negative electrode tab are disposed at the same end in the length direction of the electrode assembly, or are respectively disposed at both ends in the length direction of the electrode assembly. The width of the electrode assembly is less than or equal to 40 mm. The insulating adhesive tape includes an integrally formed first part, a second part, a third part, a fourth part, and a fifth part. The first part is attached to the first surface. The second part is attached to the third surface and is connected to the first part. The third part is attached to the second surface and is connected to the second part. The fourth part is attached to the fourth surface and is connected to the third part. The fifth part is attached to the first surface and is connected to the fourth part.

[0006] In the above technical scheme, since the insulating tape is attached to the electrode assembly, the adhesive is rolled simultaneously along the length direction of the electrode assembly, and the possibility of poor bonding such as wrinkles and bubbles is low, and the electrode assembly is attached once along the width direction. When the width of the electrode assembly is large, for example, greater than 40 mm, poor bonding such as wrinkles and bubbles is prone to occur. Therefore, when the width of the electrode assembly is large, multiple layers of insulating tape need to be set; while in the present application, the width of the electrode assembly is less than or equal to 40 mm, and when the one-piece insulating tape is attached to the electrode assembly, the possibility of poor bonding such as wrinkles and bubbles is low. Furthermore, by making the insulating tape include an integrally formed first part, a second part, a third part, a fourth part and a fifth part, the first part is attached to the first surface, the second part is attached to the third surface and connected to the first part, the third part is attached to the second surface and connected to the second part, the fourth part is attached to the fourth surface and connected to the third part, and the fifth part is attached to the first surface and connected to the fourth part, so that along the thickness direction of the electrode assembly, the third part of the insulating tape does not overlap with the second part and the fourth part, and the insulating tape occupies a smaller space in the thickness direction of the electrode assembly, which is beneficial to improving the utilization rate of the internal space of the shell in the thickness direction of the electrode assembly, thereby facilitating improving the energy density of the battery cell.

[0007] In some embodiments of the present application, the length of the electrode assembly is L1, the width of the electrode assembly is W1, and the thickness of the electrode assembly is H, satisfying L1>W1, L1>H, and W1≤20 mm.

[0008] In the above technical solution, since the electrode assembly and the shell are currently bonded only by the bottom glue, part of the side glue extends to the bottom surface of the electrode assembly and overlaps with the bottom glue, so that part of the bottom glue along the width direction of the electrode assembly is blocked by the side glue, and the other part can be bonded to the shell. When the width W1 of the electrode assembly is ≤20mm, the bonding area between the bottom glue and the shell is further reduced, affecting the stability of the battery cell when it is subjected to force. In the present application, the third part of the insulating tape covers the second surface of the electrode assembly along the width direction of the electrode assembly, and the third part as a whole can be bonded to the shell, and other parts of the insulating tape can also be bonded to the shell. When the width W1 of the electrode assembly is ≤20mm, the bonding area between the insulating tape and the shell can be larger, so that the stability of the battery cell when it is subjected to force is higher, the possibility of damage to the electrode assembly caused by the collision between the electrode assembly and the shell can be reduced, and the roller test pass rate and drop test pass rate of the battery cell can be improved.

[0009] In some embodiments of the present application, along the length direction of the electrode assembly, the length of the electrode assembly is L1, and the length of the insulating adhesive tape is L2, satisfying 50% ≤ L2 / L1 ≤ 80%. Along the width direction of the electrode assembly, the width of the electrode assembly is W1, and the width of the insulating adhesive tape after unfolding is W2, satisfying 1.5 ≤ W2 / W1 ≤ 2.

[0010] In the above technical solution, when L2 / L1 is greater than or equal to 50%, the covering area of the insulating adhesive tape on the electrode assembly is relatively large, the protection effect on the electrode assembly is good, and the drop pass rate of the battery cell is relatively high; when L2 / L1 is less than or equal to 80%, the insulating adhesive tape does not overlap with other components on the electrode assembly or the overlapping area is relatively small, so that the overall thickness of the electrode assembly and the insulating adhesive tape is relatively small, and the space utilization rate in the outer shell of the battery cell is relatively high; therefore, when 50% ≤ L2 / L1 ≤ 80%, it can not only make the protection effect of the insulating adhesive tape on the electrode assembly good and the drop pass rate of the battery cell relatively high, but also make the overall thickness of the electrode assembly and the insulating adhesive tape relatively small and the space utilization rate in the outer shell of the battery cell relatively high.

[0011] When W2 / W1 is greater than or equal to 1.5, the covering areas of the first part and the fifth part of the insulating adhesive tape on the first surface are relatively large, the protection effect on the electrode assembly is good, and the drop pass rate of the battery cell is relatively high; when W2 / W1 is less than or equal to 2, the first part and the fifth part of the insulating adhesive tape do not overlap or the overlapping area is relatively small, so that the overall thickness of the electrode assembly and the insulating adhesive tape is relatively small, and the space utilization rate in the outer shell of the battery cell is relatively high; therefore, when 1.5 ≤ W2 / W1 ≤ 2, it can not only make the protection effect of the insulating adhesive tape on the electrode assembly good and the drop pass rate of the battery cell relatively high, but also make the overall thickness of the electrode assembly and the insulating adhesive tape relatively small and the space utilization rate in the outer shell of the battery cell relatively high.

[0012] In some embodiments of the present application, along the length direction of the electrode assembly, the length of the insulating adhesive tape is L2, satisfying 100 mm ≤ L2 ≤ 160 mm. Along the width direction of the electrode assembly, the width of the insulating adhesive tape after unfolding is W2, satisfying 30 mm ≤ W2 ≤ 60 mm.

[0013] In the above technical solution, when L2 is greater than or equal to 100 mm, the covering area of the insulating adhesive tape on the electrode assembly is relatively large, the protection effect on the electrode assembly is good, and the drop pass rate of the battery cell is relatively high; when L2 is less than or equal to 160 mm, the insulating adhesive tape does not overlap with other components on the electrode assembly or the overlapping area is relatively small, so that the overall thickness of the electrode assembly and the insulating adhesive tape is relatively small, and the space utilization rate in the outer shell of the battery cell is relatively high; therefore, when 100 mm ≤ L2 ≤ 160 mm, it can not only make the protection effect of the insulating adhesive tape on the electrode assembly good and the drop pass rate of the battery cell relatively high, but also make the overall thickness of the electrode assembly and the insulating adhesive tape relatively small and the space utilization rate in the outer shell of the battery cell relatively high.

[0014] When W2 is greater than or equal to 30 mm, the covering areas of the first part and the fifth part of the insulating adhesive tape on the first surface are relatively large, the protection effect on the electrode assembly is good, and the passing rate of the battery cell during dropping is relatively high; when W2 is less than or equal to 60 mm, the first part and the fifth part of the insulating adhesive tape do not overlap or have a relatively small overlapping area, so that the overall thickness of the electrode assembly and the insulating adhesive tape is relatively small, and the space utilization rate inside the outer shell of the battery cell is relatively high; therefore, when 30 mm ≤ W2 ≤ 60 mm, it can not only make the insulating adhesive tape have a good protection effect on the electrode assembly and the passing rate of the battery cell during dropping is relatively high, but also make the overall thickness of the electrode assembly and the insulating adhesive tape relatively small, and the space utilization rate inside the outer shell of the battery cell is relatively high.

[0015] In some embodiments of the present application, along the thickness direction of the electrode assembly, the projection of the first part does not overlap with the projection of the fifth part.

[0016] In the above technical solution, by making the projection of the first part not overlap with the projection of the fifth part along the thickness direction of the electrode assembly, the space occupied by the first part and the fifth part in the thickness direction of the electrode assembly can be made relatively small, which is beneficial to improving the utilization rate of the internal space of the outer shell in the thickness direction of the electrode assembly, and thus beneficial to improving the energy density of the battery cell.

[0017] In some embodiments of the present application, along the width direction of the electrode assembly, the first part and the fifth part are arranged at intervals.

[0018] In the above technical solution, by making the first part and the fifth part arranged at intervals along the width direction of the electrode assembly, it is convenient to attach the insulating adhesive tape to the electrode assembly.

[0019] In some embodiments of the present application, at least a part of the insulating adhesive tape is bonded to the outer shell.

[0020] In the above technical solution, compared with the current method of bonding the electrode assembly to the outer shell only through the bottom adhesive, in the present application, the insulating adhesive tape can bond the first surface, the second surface, the third surface, and the fourth surface of the electrode assembly to the outer shell, so that the bonding area between the electrode assembly and the outer shell is larger and the bonding strength is higher, which can improve the stability of the battery cell when stressed.

[0021] In some embodiments of the present application, the insulating adhesive tape includes a base layer, a first adhesive layer, and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively arranged on both sides of the base layer along its thickness direction. The first adhesive layer is bonded to the electrode assembly, and the second adhesive layer is bonded to the outer shell.

[0022] In the above technical solution, by making the insulating adhesive tape include a base layer, a first adhesive layer and a second adhesive layer, and the first adhesive layer and the second adhesive layer are respectively arranged on both sides of the base layer along its thickness direction, the base layer can support the first adhesive layer and the second adhesive layer, which is convenient for the insulating adhesive tape to be attached to the electrode assembly and reduces the possibility of the insulating adhesive tape wrinkling; by making the first adhesive layer adhere to the electrode assembly and the second adhesive layer adhere to the housing, the electrode assembly and the housing can be adhered through the insulating adhesive tape, and the possibility of the electrode assembly moving in the housing is small, and the stability of the battery cell when stressed is high.

[0023] In some embodiments of the present application, the thickness of the insulating adhesive tape is H1, and 0.01 mm ≤ H1 ≤ 0.1 mm is satisfied.

[0024] In the above technical solution, when the thickness H1 of the insulating adhesive tape is greater than or equal to 0.01 mm, the adhesive force of the insulating adhesive tape can be made stronger, and then the adhesive force between the electrode assembly and the housing can be made stronger, which is beneficial to improving the stability of the battery cell when stressed. When the thickness H1 of the insulating adhesive tape is greater than or equal to 0.01 mm, the possibility of being punctured by the edge of the electrode sheet can be reduced; when the thickness H1 of the insulating adhesive tape is less than or equal to 0.1 mm, the space occupied by the insulating adhesive tape in the housing can be made smaller, so that there is more space inside the housing for accommodating the electrode assembly, which is beneficial to improving the energy density of the battery cell; therefore, when the thickness H1 of the insulating adhesive tape satisfies 0.01 mm ≤ H1 ≤ 0.1 mm, it can not only make the adhesive force of the insulating adhesive tape stronger, and then make the adhesive force between the electrode assembly and the housing stronger, which is beneficial to improving the stability of the battery cell when stressed and improving the safety of the battery cell, but also make the space occupied by the insulating adhesive tape in the housing smaller, so that there is more space inside the housing for accommodating the electrode assembly, which is beneficial to improving the energy density of the battery cell.

[0025] In some embodiments of the present application, the thickness of the base layer is H2, the thickness of the first adhesive layer is H3, and the thickness of the second adhesive layer is H4, and 0.2 ≤ (H3 / H2) ≤ 2.5, 0.2 ≤ (H4 / H2) ≤ 2.5 are satisfied.

[0026] In the above technical solution, when H3:H2 is greater than or equal to 0.2:1, the adhesive force of the first adhesive layer can be made stronger, so that the adhesive force between the insulating adhesive tape and the electrode assembly is stronger, and the electrode assembly is not easy to displace relative to the insulating adhesive tape; when H3:H2 is less than or equal to 2.5:1, the supporting force of the base layer on the first adhesive layer is better, and the first adhesive layer is not easy to deform, wrinkle and other problems; when 0.2 ≤ H3 / H2 ≤ 2.5, it can not only make the adhesive force between the insulating adhesive tape and the electrode assembly stronger, and the electrode assembly is not easy to displace relative to the insulating adhesive tape, but also make the supporting force of the base layer on the first adhesive layer better, and the first adhesive layer is not easy to deform, wrinkle and other problems.

[0027] When H4:H2 is greater than or equal to 0.2:1, the adhesive force of the second adhesive layer can be made stronger, so that the adhesive force between the insulating adhesive tape and the housing is stronger, and the insulating adhesive tape is not likely to displace relative to the housing; when H4:H2 is less than or equal to 2.5:1, the supporting force of the base layer on the second adhesive layer can be made better, and problems such as deformation and wrinkling of the second adhesive layer are not likely to occur; when 0.2≤(H4 / H2)≤2.5, both the adhesive force between the insulating adhesive tape and the housing can be made stronger, the insulating adhesive tape is not likely to displace relative to the housing, and the supporting force of the base layer on the second adhesive layer can be made better, and problems such as deformation and wrinkling of the second adhesive layer are not likely to occur.

[0028] In some embodiments of the present application, the melting point of the base layer is T, satisfying 150°C≤T≤300°C.

[0029] In the above technical solution, when the melting point T of the base layer is greater than or equal to 150°C, the possibility of melting of the insulating adhesive tape during the welding of the housing can be reduced, and the connection reliability of the insulating adhesive tape to the electrode assembly and the housing can be improved; when the melting point T of the base layer is less than or equal to 300°C, the preparation of the insulating adhesive tape can be facilitated; therefore, when the melting point T of the base layer satisfies 150°C≤T≤300°C, both the possibility of melting of the insulating adhesive tape during the welding of the housing can be reduced, the connection reliability of the insulating adhesive tape to the electrode assembly and the housing can be improved, and the preparation of the insulating adhesive tape can be facilitated.

[0030] In some embodiments of the present application, the adhesive force of the first adhesive layer is F1, F1≥0.1N / mm; the adhesive force of the second adhesive layer is F2, F2≥0.1N / mm.

[0031] In the above technical solution, by making the adhesive force F1 of the first adhesive layer ≥0.1N / mm, the adhesive force between the electrode assembly and the insulating adhesive tape can be made larger, the possibility of displacement of the electrode assembly relative to the insulating adhesive tape can be reduced, the possibility of the electrode assembly moving around in the housing can be reduced, and the stability of the battery cell when stressed is higher. By making the adhesive force F2 of the second adhesive layer ≥0.1N / mm, the adhesive force between the insulating adhesive tape and the housing can be made larger, the possibility of displacement of the insulating adhesive tape relative to the housing can be reduced, the possibility of the electrode assembly moving around in the housing can be reduced, and the stability of the battery cell when stressed is higher.

[0032] In some embodiments of the present application, the housing includes a housing body and a housing cover. The housing body includes a bottom wall and a side wall surrounding the bottom wall. One end of the side wall is connected to the bottom wall, and the other end of the side wall encloses an opening. The housing cover is connected to the side wall and covers the opening. The housing cover and the bottom wall are disposed opposite to each other in the thickness direction of the electrode assembly. The first part and the fifth part are both adhered to the housing cover, and the third part is adhered to the bottom wall.

[0033] In the above technical solution, by bonding both the first part and the fifth part to the shell cover and bonding the third part to the bottom wall, the bonding area between the electrode assembly and the outer shell can be increased, the stability of the battery cell when stressed can be improved, the possibility of damage to the electrode assembly caused by collision between the electrode assembly and the outer shell can be reduced, and the passing rates of the drum test and the drop test of the battery cell can be increased.

[0034] In some embodiments of the present application, the side wall includes a first side wall and a second side wall oppositely arranged along the width direction of the battery cell, the second part is bonded to the first side wall, and the fourth part is bonded to the second side wall.

[0035] In the above technical solution, by bonding the second part to the first side wall and bonding the fourth part to the second side wall, the bonding area between the electrode assembly and the outer shell can be further increased, the stability of the battery cell when stressed can be further improved, the possibility of damage to the electrode assembly caused by collision between the electrode assembly and the outer shell can be further reduced, and the passing rates of the drum test and the drop test of the battery cell can be further increased.

[0036] In some embodiments of the present application, the electrode assembly is of a laminated structure, and the electrode assembly includes a plurality of positive electrode plates and a plurality of negative electrode plates laminated along its thickness direction.

[0037] In the above technical solution, since each electrode plate in the laminated-structured electrode assembly has an edge along the width direction of the electrode assembly, when the electrode assembly is assembled with the outer shell, if the electrode plate interferes with the outer shell, the edge of the electrode plate is likely to be deformed or damaged. By attaching the second part of the insulating adhesive tape to the third surface and the fourth part to the fourth surface, the insulating adhesive tape can protect the electrode assembly and reduce the possibility of deformation or damage when the electrode assembly is assembled with the outer shell, which is beneficial to improving the preparation yield of the battery cell.

[0038] In some embodiments of the present application, the plurality of negative electrode plates include a first negative electrode plate, the second surface is a surface of the first negative electrode plate, and the third part is attached to the first negative electrode plate. The first negative electrode plate includes a first negative current collector, and the thickness of the first negative current collector is less than the thickness of the negative current collectors of other negative electrode plates.

[0039] In the above technical solution, in the current solution of separately providing a bottom adhesive and a side adhesive on the electrode assembly, there is a gap between the bottom adhesive and the side adhesive on the bottom surface of the electrode assembly, and a part of the negative electrode tab at the bottom of the electrode assembly is exposed. When the battery cell is stressed, the negative electrode tab is easily stressed, resulting in tearing of the negative current collector and further problems such as precipitation of metal ions. In this application, the third part of the insulating adhesive tape covers the second surface of the electrode assembly along the width direction of the electrode assembly. When the battery cell is stressed, the insulating adhesive tape on the first negative electrode tab can play a buffering role, reducing the possibility of tearing of the first negative electrode tab, so that the thickness of the first negative current collector can be made smaller, and there is more space in the outer casing along the thickness direction of the electrode assembly to accommodate the active material, which is beneficial to improving the energy density of the battery cell.

[0040] In some embodiments of the present application, the thickness of the first negative current collector is H5, satisfying 4μm ≤ H5 ≤ 25μm.

[0041] In the above technical solution, when the thickness H5 of the first negative current collector is greater than or equal to 4μm, the first negative current collector can have a greater bearing capacity for the first negative active material layer of the first negative electrode tab and is not easily broken; when the thickness H5 of the first negative current collector is less than or equal to 25μm, there is more space in the outer casing along the thickness direction of the electrode assembly to accommodate the active material, which is beneficial to improving the energy density of the battery cell; therefore, when the thickness H5 of the first negative current collector satisfies 4μm ≤ H5 ≤ 25μm, the first negative current collector can not only have a greater bearing capacity for the first negative active material layer of the first negative electrode tab and is not easily broken, but also there is more space in the outer casing along the thickness direction of the electrode assembly to accommodate the active material, which is beneficial to improving the energy density of the battery cell.

[0042] In some embodiments of the present application, the outer casing is a steel shell.

[0043] In the above technical solution, by making the outer casing a steel shell, the stress-bearing performance of the outer casing can be stronger and the protection effect on the electrode assembly is better.

[0044] In a second aspect, the present application provides an electrical device, including the battery cell as described above, and the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings.

[0046] Figure 1Schematic three-dimensional structure diagram of a battery cell provided by some embodiments of the present application;

[0047] Figure 2 Exploded structure diagram of a battery cell provided by some embodiments of the present application;

[0048] Figure 3 Exploded diagram of a partial structure of a battery cell provided by some embodiments of the present application;

[0049] Figure 4 Schematic structure diagram of a battery cell from a perspective provided by some embodiments of the present application;

[0050] Figure 5 For Figure 4 Cross-sectional structure diagram of a partial structure of the battery cell in [reference] along A-A;

[0051] Figure 6 Cross-sectional structure diagram of the insulating adhesive tape of a battery cell provided by some embodiments of the present application.

[0052] Icons: 10 - battery cell; 100 - outer shell; 101 - opening; 102 - liquid injection hole; 110 - housing; 111 - bottom wall; 112 - side wall; 112a - first side wall; 112b - second side wall; 112c - third side wall; 112d - fourth side wall; 120 - lid; 200 - electrode assembly; 201 - first surface; 202 - second surface; 203 - third surface; 204 - fourth surface; 210 - positive tab; 220 - negative tab; 230 - positive electrode plate; 240 - negative electrode plate; 240a - first negative electrode plate; 300 - insulating adhesive tape; 301 - base layer; 302 - first adhesive layer; 303 - second adhesive layer; 310 - first part; 320 - second part; 330 - third part; 340 - fourth part; 350 - fifth part; 410 - protective adhesive tape; 420 - electrode terminal; X - thickness direction of the electrode assembly; Y - width direction of the electrode assembly; Z - length direction of the electrode assembly. Detailed implementation manners

[0053] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0055] The terms "first", "second", etc. in the description and claims of this application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0056] Referring to "embodiment" in this application means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appearing at various positions in the description does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0057] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0058] With the development of the new energy industry, batteries are gradually developing in the direction of high energy density and high power density. However, the volume of the battery compartment of the electrical device for accommodating the battery cells is limited, which restricts the way of increasing the energy density of the battery cells by increasing the volume of the battery cells. Therefore, it is more feasible to improve the energy density of the battery cells by changing the structure of the battery cells themselves.

[0059] Currently, a bottom glue is provided between the bottom surface of the electrode assembly and the bottom wall of the outer shell. The bottom glue is bonded to the electrode assembly and the outer shell respectively to fix the electrode assembly and the outer shell. A side glue is provided between the side surface of the electrode assembly and the outer shell. The side wall glue is bonded to the electrode assembly to protect the electrode assembly. In order to make the side glue cover the side surface of the electrode assembly, a part of the side glue needs to extend to the bottom surface of the electrode assembly and overlap with the bottom glue, but it will affect the utilization rate of the internal space of the outer shell in the thickness direction of the electrode assembly, and further affect the energy density of the battery cells.

[0060] In order to improve the energy density of a battery cell, the present application provides a battery cell, which includes a shell, an electrode assembly and insulating tape, wherein the electrode assembly is arranged in the shell, and the electrode assembly includes a first surface and a second surface opposite to each other along its thickness direction, and a third surface and a fourth surface opposite to each other along its width direction. The electrode assembly includes a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are arranged at the same end of the length direction of the electrode assembly, or, respectively, at both ends of the length direction of the electrode assembly. The width of the electrode assembly is less than or equal to 40 mm. The insulating tape includes an integrally formed first part, a second part, a third part, a fourth part and a fifth part, wherein the first part is attached to the first surface. The second part is attached to the third surface and connected to the first part. The third part is attached to the second surface and connected to the second part. The fourth part is attached to the fourth surface and connected to the third part. The fifth part is attached to the first surface and connected to the fourth part.

[0061] In a battery cell of this structure, since the insulating tape is rolled simultaneously along the length direction of the electrode assembly when being attached to the electrode assembly, the possibility of poor bonding such as wrinkles and bubbles is low, and the electrode assembly is attached once along the width direction. When the width of the electrode assembly is large, for example, greater than 40 mm, poor bonding such as wrinkles and bubbles is prone to occur. Therefore, when the width of the electrode assembly is large, multiple strips of tape are required. In the present application, the width of the electrode assembly is less than or equal to 40 mm, and when the one-piece insulating tape is attached to the electrode assembly, the possibility of poor bonding such as wrinkles and bubbles is low. Furthermore, by making the insulating tape include an integrally formed first part, a second part, a third part, a fourth part and a fifth part, the first part is attached to the first surface, the second part is attached to the third surface and connected to the first part, the third part is attached to the second surface and connected to the second part, the fourth part is attached to the fourth surface and connected to the third part, and the fifth part is attached to the first surface and connected to the fourth part, so that along the thickness direction of the electrode assembly, the third part of the insulating tape does not overlap with the second part and the fourth part, and the insulating tape occupies a smaller space in the thickness direction of the electrode assembly, which is beneficial to improving the utilization rate of the internal space of the shell in the thickness direction of the electrode assembly, thereby facilitating improving the energy density of the battery cell.

[0062] It should be noted that, as a rectangular parallelepiped object, the electrode assembly has a length greater than its width, and a width greater than its thickness.

[0063] The battery cell provided in the embodiment of the present application can be a secondary battery or a primary battery, for example, a lithium ion battery, a sodium ion battery or a magnesium ion battery, etc., which is not limited in the embodiment of the present application. The electrochemical device can be cylindrical, flat, rectangular or other shapes, etc., which is not limited in the embodiment of the present application.

[0064] An embodiment of the present application provides an electrical device using a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like.

[0065] See Figures 1 to 3 , Figure 1 is a schematic three-dimensional structure diagram of a battery cell provided by some embodiments of the present application; Figure 2 is an exploded structure diagram of a battery cell provided by some embodiments of the present application; Figure 3 is an exploded schematic diagram of a partial structure of a battery cell provided by some embodiments of the present application.

[0066] An embodiment of the present application provides a battery cell 10, which includes a housing 100, an electrode assembly 200, and an insulating adhesive tape 300. The electrode assembly 200 is disposed inside the housing 100. The electrode assembly 200 includes a first surface 201 and a second surface 202 opposite to each other along its thickness direction X, and a third surface 203 and a fourth surface 204 opposite to each other along its width direction Y. The electrode assembly 200 includes a positive electrode tab 210 and a negative electrode tab 220. The positive electrode tab 210 and the negative electrode tab 220 are disposed at the same end in the length direction Z of the electrode assembly, or are respectively disposed at both ends in the length direction Z of the electrode assembly. The width of the electrode assembly 200 is less than or equal to 40 mm.

[0067] The insulating adhesive tape 300 includes an integrally formed first part 310, a second part 320, a third part 330, a fourth part 340, and a fifth part 350. The first part 310 is attached to the first surface 201. The second part 320 is attached to the third surface 203 and is connected to the first part 310. The third part 330 is attached to the second surface 202 and is connected to the second part 320. The fourth part 340 is attached to the fourth surface 204 and is connected to the third part 330. The fifth part 350 is attached to the first surface 201 and is connected to the fourth part 340.

[0068] When the insulating adhesive tape 300 is attached to the electrode assembly 200, when rolling and pressing are performed simultaneously along the length direction Z of the electrode assembly during the taping process, the possibility of poor bonding such as wrinkles and bubbles is relatively low. However, along the width direction Y of the electrode assembly, it is a one-time attachment. When the width of the electrode assembly 200 is relatively large, for example, greater than 40 mm, it is easy to have poor bonding conditions such as wrinkles and bubbles. Therefore, when the width of the electrode assembly 200 is large, multiple insulating adhesive tapes 300 need to be provided. In this application, the width of the electrode assembly 200 is less than or equal to 40 mm. When the integrally formed insulating adhesive tape 300 is attached to the electrode assembly 200, the possibility of poor bonding such as wrinkles and bubbles is relatively low. And by making the insulating adhesive tape 300 include an integrally formed first part 310, second part 320, third part 330, fourth part 340, and fifth part 350, the first part 310 is attached to the first surface 201, the second part 320 is attached to the third surface 203 and is connected to the first part 310, the third part 330 is attached to the second surface 202 and is connected to the second part 320, the fourth part 340 is attached to the fourth surface 204 and is connected to the third part 330, and the fifth part 350 is attached to the first surface 201 and is connected to the fourth part 340, such that along the thickness direction X of the electrode assembly, the third part 330 of the insulating adhesive tape 300 does not overlap with the second part 320 and the fourth part 340. The insulating adhesive tape 300 occupies less space in the thickness direction X of the electrode assembly, which is beneficial to improving the utilization rate of the internal space of the housing 100 in the thickness direction X of the electrode assembly, and thus is beneficial to improving the energy density of the battery cell 10.

[0069] In some embodiments, the housing 100 can be made of materials with relatively high strength, such as metal materials like steel and aluminum alloy, so that the housing 100 has relatively high stress-bearing performance. As a result, the housing 100 is not easily deformed or damaged due to stress or environmental changes, and thus the reliability of the battery cell 10 can be higher.

[0070] In other embodiments, the housing 100 can also be made of non-metal materials with relatively high strength, such as carbon fiber and hard plastic.

[0071] In some embodiments, the battery cell 10 further includes an electrolyte solution, which is accommodated in the outer shell 100. The electrode assembly 200 is composed of a positive electrode tab 230, a negative electrode tab 240, and a separator. The battery cell 10 mainly operates by the movement of metal ions between the positive electrode tab 230 and the negative electrode tab 240. The positive electrode tab 230 includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The part of the positive electrode current collector without the coated positive electrode active material layer serves as the positive electrode tab 210 to realize the electrical energy input or output of the positive electrode tab 230 through the positive electrode tab 210. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary material, lithium manganate, etc. The negative electrode tab 240 includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The part of the negative electrode current collector without the coated negative electrode active material layer serves as the negative electrode tab 220 to realize the electrical energy input or output of the negative electrode tab 240 through the negative electrode tab 220. The material of the negative electrode current collector can be copper, and the negative electrode active material can be a carbon material or a silicon material, etc. The material of the separator can be polypropylene (PP), polyethylene (PE), etc. The electrolyte solution can include an organic solvent, an electrolyte lithium salt, etc.

[0072] In some embodiments, the electrode assembly 200 can be a laminated structure formed by laminating the negative electrode tab 240, the separator, and the positive electrode tab 230.

[0073] In some other embodiments, the electrode assembly 200 can also be a wound structure formed by winding the negative electrode tab 240, the separator, and the positive electrode tab 230.

[0074] In some embodiments, the battery cell 10 is arranged in a cuboid shape, and the top corners are rounded, which can better fit into the rounded battery compartment in the electrical device.

[0075] In some other embodiments, the top corners of the battery cell 10 can also be square.

[0076] See Figure 4 and Figure 5 , Figure 4 is a schematic structural diagram of a battery cell from a perspective provided by some embodiments of the present application; Figure 5 is Figure 4 a schematic cross-sectional structural diagram of a partial structure of the battery cell in

[0077] In some embodiments, the length of the electrode assembly 200 is L1, the width of the electrode assembly 200 is W1, and the thickness of the electrode assembly 200 is H, satisfying L1>W1, L1>H, and W1≤20 mm. For example, L1 may be 1.1*W1, 1.3*W1, or 1.5*W1, etc. For example, L1 may be 1.1*H, 1.3*H, or 1.5*H, etc. For example, W1 may be 20 mm, 18 mm, 15 mm, 10 mm, or 8 mm, etc.

[0078] Since the electrode assembly 200 and the outer shell 100 are currently bonded only by the bottom glue, part of the side glue extends to the bottom surface of the electrode assembly 200 and overlaps with the bottom glue, so that part of the bottom glue along the width direction Y of the electrode assembly is blocked by the side glue, and the other part can be bonded to the outer shell 100. When the width W1 of the electrode assembly 200 is ≤20mm, the area blocked by the side glue is further increased, and the bonding area between the bottom glue and the outer shell 100 is smaller, which affects the stability of the battery cell 10 when subjected to force. In the present application, the third part 330 of the insulating tape 300 covers the second surface 202 of the electrode assembly 200 along the width direction Y of the electrode assembly, and the third part 330 as a whole can be bonded to the outer shell 100, and other parts of the insulating tape 300 can also be bonded to the outer shell 100. When the width W1 of the electrode assembly 200 is ≤20mm, the bonding area between the insulating tape 300 and the outer shell 100 can be larger, so that the stability of the battery cell 10 when subjected to force is higher, which can reduce the possibility of damage to the electrode assembly 200 caused by the collision between the electrode assembly 200 and the outer shell 100, and can improve the roller test pass rate and drop test pass rate of the battery cell 10.

[0079] In some embodiments, along the length direction Z of the electrode assembly, the length of the electrode assembly 200 is L1, and the length of the insulating tape 300 is L2, satisfying 50%≤L2 / L1≤80%. For example, L2 / L1 can be 50%, 60%, 65%, 70% or 80%, etc.

[0080] When L2 / L1 is greater than or equal to 50%, the insulating tape 300 covers a larger area of ​​the electrode assembly 200, has a better protective effect on the electrode assembly 200, and has a higher drop pass rate of the battery cell 10; when L2 / L1 is less than or equal to 80%, the insulating tape 300 does not overlap with other components on the electrode assembly 200 or the overlapping area is small, so that the overall thickness of the electrode assembly 200 and the insulating tape 300 is small, and the space utilization rate inside the shell 100 of the battery cell 10 is high; therefore, when 50%≤L2 / L1≤80%, the insulating tape 300 can have a better protective effect on the electrode assembly 200, the drop pass rate of the battery cell 10 is high, and the overall thickness of the electrode assembly 200 and the insulating tape 300 is small, and the space utilization rate inside the shell 100 of the battery cell 10 is high.

[0081] In some embodiments, along the width direction Y of the electrode assembly, the width of the electrode assembly 200 is W1, and the width of the insulating adhesive tape 300 after unfolding is W2, satisfying 1.5 ≤ W2 / W1 ≤ 2. For example, W2 / W1 can be 1.5, 1.6, 1.7, 1.9, or 2, etc.

[0082] When W2 / W1 is greater than or equal to 1.5, the covering areas of the first part 310 and the fifth part 350 of the insulating adhesive tape 300 on the first surface 201 are relatively large, the protection effect on the electrode assembly 200 is better, and the drop passing rate of the battery cell 10 is relatively high; when W2 / W1 is less than or equal to 2, the first part 310 and the fifth part 350 of the insulating adhesive tape 300 do not overlap or have a relatively small overlapping area, so that the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 is relatively small, and the space utilization rate in the outer shell 100 of the battery cell 10 is relatively high; therefore, when 1.5 ≤ W2 / W1 ≤ 2, it can not only make the insulating adhesive tape 300 have a better protection effect on the electrode assembly 200 and the drop passing rate of the battery cell 10 is relatively high, but also make the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 relatively small, and the space utilization rate in the outer shell 100 of the battery cell 10 is relatively high.

[0083] In some embodiments, along the length direction Z of the electrode assembly, the length of the insulating adhesive tape 300 is L2, satisfying 100 mm ≤ L2 ≤ 160 mm. For example, L2 can be 100 mm, 110 mm, 130 mm, 150 mm, or 160 mm, etc.

[0084] When L2 is greater than or equal to 100 mm, the covering area of the insulating adhesive tape 300 on the electrode assembly 200 is relatively large, the protection effect on the electrode assembly 200 is better, and the drop passing rate of the battery cell 10 is relatively high; when L2 is less than or equal to 160 mm, the insulating adhesive tape 300 does not overlap with other components on the electrode assembly 200 or has a relatively small overlapping area, so that the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 is relatively small, and the space utilization rate in the outer shell 100 of the battery cell 10 is relatively high; therefore, when 100 mm ≤ L2 ≤ 160 mm, it can not only make the insulating adhesive tape 300 have a better protection effect on the electrode assembly 200 and the drop passing rate of the battery cell 10 is relatively high, but also make the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 relatively small, and the space utilization rate in the outer shell 100 of the battery cell 10 is relatively high.

[0085] In some embodiments, along the width direction Y of the electrode assembly, the width of the insulating adhesive tape 300 after unfolding is W2, satisfying 30 mm ≤ W2 ≤ 40 mm. For example, W2 can be 30 mm, 32 mm, 35 mm, 38 mm, or 40 mm, etc.

[0086] When W2 is greater than or equal to 30 mm, the covering areas of the first part 310 and the fifth part 350 of the insulating adhesive tape 300 on the first surface 201 are larger, the protection effect on the electrode assembly 200 is better, and the drop passing rate of the battery cell 10 is higher; when W2 is less than or equal to 40 mm, the first part 310 and the fifth part 350 of the insulating adhesive tape 300 do not overlap or have a smaller overlapping area, so that the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 is smaller, and the space utilization rate inside the outer shell 100 of the battery cell 10 is higher; therefore, when 30 mm ≤ W2 ≤ 40 mm, it can not only make the insulating adhesive tape 300 have a better protection effect on the electrode assembly 200 and the battery cell 10 have a higher drop passing rate, but also make the overall thickness of the electrode assembly 200 and the insulating adhesive tape 300 smaller, and the space utilization rate inside the outer shell 100 of the battery cell 10 is higher.

[0087] See Figure 2 and Figure 5 , in some embodiments, along the thickness direction X of the electrode assembly, the projection of the first part 310 does not overlap with the projection of the fifth part 350.

[0088] By making the projection of the first part 310 not overlap with the projection of the fifth part 350 along the thickness direction X of the electrode assembly, the space occupied by the first part 310 and the fifth part 350 in the thickness direction X of the electrode assembly can be made smaller, which is beneficial to improving the utilization rate of the internal space of the outer shell 100 in the thickness direction X of the electrode assembly, and thus beneficial to improving the energy density of the battery cell 10.

[0089] In some embodiments, along the width direction Y of the electrode assembly, the first part 310 and the fifth part 350 are arranged at intervals.

[0090] By making the first part 310 and the fifth part 350 arranged at intervals along the width direction Y of the electrode assembly, it is convenient to attach the insulating adhesive tape 300 to the electrode assembly 200.

[0091] In some embodiments, at least part of the insulating adhesive tape 300 is bonded to the outer shell 100.

[0092] Compared with the current method of bonding the electrode assembly 200 and the outer shell 100 only through the bottom adhesive, in this application, the insulating adhesive tape 300 can bond the first surface 201, the second surface 202, the third surface 203, and the fourth surface 204 of the electrode assembly 200 to the outer shell 100, so that the bonding area between the electrode assembly 200 and the outer shell 100 is larger and the bonding strength is higher, which can improve the stability of the battery cell 10 when stressed.

[0093] In some embodiments, the second part 320, the third part 330, and the fourth part 340 are respectively bonded to the outer shell 100, such that the bonding area between the electrode assembly 200 and the outer shell 100 is relatively large, the bonding strength is relatively high, and the stability of the battery cell 10 under stress is relatively high.

[0094] In some embodiments, the first part 310 and the fifth part 350 are respectively bonded to the outer shell 100, which can further make the bonding area between the electrode assembly 200 and the outer shell 100 larger, the bonding strength higher, and can improve the stability of the battery cell 10 under stress.

[0095] See Figure 6 , Figure 6 which is a schematic cross-sectional structure diagram of the insulating adhesive tape of the battery cell provided in some embodiments of the present application.

[0096] In some embodiments, the insulating adhesive tape 300 includes a base layer 301, a first adhesive layer 302, and a second adhesive layer 303. The first adhesive layer 302 and the second adhesive layer 303 are respectively disposed on both sides of the base layer 301 along its thickness direction. The first adhesive layer 302 is bonded to the electrode assembly 200, and the second adhesive layer 303 is bonded to the outer shell 100.

[0097] By making the insulating adhesive tape 300 include the base layer 301, the first adhesive layer 302, and the second adhesive layer 303, and the first adhesive layer 302 and the second adhesive layer 303 are respectively disposed on both sides of the base layer 301 along its thickness direction, the base layer 301 can support the first adhesive layer 302 and the second adhesive layer 303, facilitating the insulating adhesive tape 300 to be attached to the electrode assembly 200 and reducing the possibility of the insulating adhesive tape 300 wrinkling; by making the first adhesive layer 302 bonded to the electrode assembly 200 and the second adhesive layer 303 bonded to the outer shell 100, the electrode assembly 200 and the outer shell 100 can be bonded through the insulating adhesive tape 300, and the possibility of the electrode assembly 200 moving around in the outer shell 100 is small, and the stability of the battery cell 10 under stress is high.

[0098] In some embodiments, the thickness of the insulating adhesive tape 300 is H1, satisfying 0.01 mm ≤ H1 ≤ 0.1 mm. For example, H1 can be 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, or 0.1 mm, etc.

[0099] When the thickness H1 of the insulating adhesive tape 300 is greater than or equal to 0.01 mm, the adhesion of the insulating adhesive tape 300 can be made stronger, and then the adhesion between the electrode assembly 200 and the housing 100 can be made stronger, which is beneficial to improving the stability of the battery cell 10 when stressed; when the thickness H1 of the insulating adhesive tape 300 is less than or equal to 0.1 mm, the space occupied by the insulating adhesive tape 300 in the housing 100 can be made smaller, so that there is more space inside the housing 100 for accommodating the electrode assembly 200, which is beneficial to improving the energy density of the battery cell 10; therefore, when the thickness H1 of the insulating adhesive tape 300 satisfies 0.01 mm ≤ H1 ≤ 0.1 mm, it can not only make the adhesion of the insulating adhesive tape 300 stronger, and then make the adhesion between the electrode assembly 200 and the housing 100 stronger, which is beneficial to improving the stability of the battery cell 10 when stressed, but also make the space occupied by the insulating adhesive tape 300 in the housing 100 smaller, so that there is more space inside the housing 100 for accommodating the electrode assembly 200, which is beneficial to improving the energy density of the battery cell 10.

[0100] In some embodiments, the thickness of the base layer 301 is H2, and the thickness of the first adhesive layer 302 is H3, satisfying 0.2 ≤ H3 / H2 ≤ 2.5. For example, H3 / H2 can be 0.2, 0.5, 1, 1.8, 2.5, etc.

[0101] When H3 / H2 is greater than or equal to 0.2, the adhesion of the first adhesive layer 302 can be made stronger, so that the adhesion between the insulating adhesive tape 300 and the electrode assembly 200 is stronger, and the electrode assembly 200 is not likely to displace relative to the insulating adhesive tape 300; when H3 / H2 is less than or equal to 2.5, the support force of the base layer 301 on the first adhesive layer 302 is better, and the first adhesive layer 302 is not likely to deform, wrinkle, etc.; when 0.2 ≤ H3 / H2 ≤ 2.5, it can not only make the adhesion between the insulating adhesive tape 300 and the electrode assembly 200 stronger, and the electrode assembly 200 is not likely to displace relative to the insulating adhesive tape 300, but also make the support force of the base layer 301 on the first adhesive layer 302 better, and the first adhesive layer 302 is not likely to deform, wrinkle, etc.

[0102] In some embodiments, the thickness of the second adhesive layer 303 is H4, satisfying 0.2 ≤ H4 / H2 ≤ 2.5. For example, H4 / H2 can be 0.2, 0.5, 1, 1.8, 2.5, etc.

[0103] When H4:H2 is greater than or equal to 0.2, the adhesive force of the second adhesive layer 303 can be made stronger, so that the adhesive force between the insulating adhesive tape 300 and the housing 100 is stronger, and the insulating adhesive tape 300 is not likely to displace relative to the housing 100; when H4 / H2 is less than or equal to 2.5, the supporting force of the base layer 301 on the second adhesive layer 303 can be made better, and the second adhesive layer 303 is not likely to deform, wrinkle, etc.; when 0.2≤H4 / H2≤2.5, both the adhesive force between the insulating adhesive tape 300 and the housing 100 can be made stronger, the insulating adhesive tape 300 is not likely to displace relative to the housing 100, and the supporting force of the base layer 301 on the second adhesive layer 303 can be made better, and the second adhesive layer 303 is not likely to deform, wrinkle, etc.

[0104] In some embodiments, the melting point of the base layer 301 is T, satisfying 150°C≤T≤300°C. For example, T can be 150°C, 180°C, 200°C, 250°C or 300°C, etc.

[0105] When the melting point T of the base layer 301 is greater than or equal to 150°C, the possibility of the insulating adhesive tape 300 melting during the welding of the housing 100 can be reduced, and the connection reliability of the insulating adhesive tape 300 to the electrode assembly 200 and the housing 100 can be improved; when the melting point T of the base layer 301 is less than or equal to 300°C, it is convenient for the preparation of the insulating adhesive tape 300; therefore, when the melting point T of the base layer 301 satisfies 150°C≤T≤300°C, both the possibility of the insulating adhesive tape 300 melting during the welding of the housing 100 can be reduced, and the connection reliability of the insulating adhesive tape 300 to the electrode assembly 200 and the housing 100 can be improved, and it is also convenient for the preparation of the insulating adhesive tape 300.

[0106] In some embodiments, the material of the base layer 301 may include at least one of polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), and polytetrafluoroethylene (PTFE). It can make the melting point of the base layer 301 higher and the support for the first adhesive layer 302 and the second adhesive layer 303 better.

[0107] In some embodiments, the adhesive force of the first adhesive layer 302 is F1, F1≥0.1N / mm. For example, F1 can be 0.1N / mm, 0.2N / mm, 0.5N / mm, 0.8N / mm or 1N / mm, etc.

[0108] By making the adhesive force F1 of the first adhesive layer 302≥0.1N / mm, the adhesive force between the electrode assembly 200 and the insulating adhesive tape 300 can be made larger, the possibility of the electrode assembly 200 displacing relative to the insulating adhesive tape 300 can be reduced, the possibility of the electrode assembly 200 moving around in the housing 100 can be reduced, and the stability of the battery cell 10 when stressed is higher.

[0109] In some embodiments, the adhesive force of the second adhesive layer 303 is F2, and F2 ≥ 0.1 N / mm. For example, F2 can be 0.1 N / mm, 0.2 N / mm, 0.5 N / mm, 0.8 N / mm, 1 N / mm, etc.

[0110] By making the adhesive force F2 of the second adhesive layer 303 ≥ 0.1 N / mm, the adhesive force between the insulating adhesive tape 300 and the housing 100 can be made larger, reducing the possibility of displacement of the insulating adhesive tape 300 relative to the housing 100, making the possibility of the electrode assembly 200 moving around in the housing 100 smaller, and the stability of the battery cell 10 under force is higher.

[0111] In some embodiments, the method for testing the adhesive force includes:

[0112] 1. Take a sample of the insulating adhesive tape 300 with a size of 20 mm * 100 mm (taking the insulating adhesive tape 300 with a single-layer adhesive layer as an example), and paste the sample of the insulating adhesive tape 300 between an aluminum foil with a thickness of 12 μm and an aluminum-plastic film with a thickness of 87 ± 4 μm (the adhesive layer is pasted on the smooth surface of the aluminum foil). The aluminum foil surface is adhered to the steel plate with a non-woven fabric base double-sided tape (5000 NS) or other double-sided adhesives.

[0113] 2. Pad a silicone pad on the side of the aluminum-plastic film, and hot-press the aluminum foil, the insulating adhesive tape 300, and the aluminum-plastic film at a temperature of 85 °C and a pressure of 392 Kg for 1 hour.

[0114] 3. In an environment with a temperature of 23 ± 2 °C and a relative humidity (RH) of 55 ± 5%, use a high-speed tensile tester to clamp the tape and the steel plate respectively, and pull it at an angle of 180° and a speed of 50 mm / min. Take the average value of a 60-mm section after stabilization (if there is a severely serrated curve, take the average value of the maximum values at every 12 mm of the stabilized curve) as the test value, then the bonding force F after hot pressing = test value / 20 (N / mm).

[0115] In some embodiments, the first adhesive layer 302 includes at least one of styrene-isoprene-styrene and polyolefin, and the second adhesive layer 303 includes at least one of styrene-isoprene-styrene and polyolefin, which can make the adhesive force between the first adhesive layer 302 / the second adhesive layer 303 larger.

[0116] See Figure 2, in some embodiments, the outer shell 100 includes a housing 110 and a housing cover 120. The housing 110 includes a bottom wall 111 and a side wall 112 surrounding the bottom wall 111. One end of the side wall 112 is connected to the bottom wall 111, and the other end of the side wall 112 encloses an opening 101. The housing cover 120 is connected to the side wall 112 and covers the opening 101. The housing cover 120 and the bottom wall 111 are oppositely arranged along the thickness direction X of the electrode assembly. Both the first part 310 and the fifth part 350 are bonded to the housing cover 120, and the third part 330 is bonded to the bottom wall 111.

[0117] By bonding both the first part 310 and the fifth part 350 to the housing cover 120 and bonding the third part 330 to the bottom wall 111, the bonding area between the electrode assembly 200 and the outer shell 100 can be made larger, the stability of the battery cell 10 when stressed can be made higher, the possibility of damage to the electrode assembly 200 caused by collision between the electrode assembly 200 and the outer shell 100 can be reduced, and the passing rates of the drum test and the drop test of the battery cell 10 can be improved.

[0118] In some embodiments, the side wall 112 includes a first side wall 112a and a second side wall 112b that are oppositely arranged along the width direction of the battery cell 10. The second part 320 is bonded to the first side wall 112a, and the fourth part 340 is bonded to the second side wall 112b.

[0119] By bonding the second part 320 to the first side wall 112a and bonding the fourth part 340 to the second side wall 112b, the bonding area between the electrode assembly 200 and the outer shell 100 can be further increased, the stability of the battery cell 10 when stressed can be made higher, the possibility of damage to the electrode assembly 200 caused by collision between the electrode assembly 200 and the outer shell 100 can be further reduced, and the passing rates of the drum test and the drop test of the battery cell 10 can be further improved.

[0120] In some embodiments, the electrode assembly 200 has a stacked structure, and the electrode assembly 200 includes a plurality of positive electrode plates 230 and a plurality of negative electrode plates 240 that are stacked along its thickness direction.

[0121] Since each electrode plate in the stacked-structured electrode assembly 200 has an edge along the width direction Y of the electrode assembly, when the electrode assembly 200 is assembled with the outer shell 100, if the electrode plate interferes with the outer shell 100, the edge of the electrode plate is likely to be deformed or damaged. By attaching the second part 320 of the insulating adhesive tape 300 to the third surface 203 and the fourth part 340 to the fourth surface 204, the insulating adhesive tape 300 can protect the electrode assembly 200 and reduce the possibility of deformation or damage when the electrode assembly 200 is assembled with the outer shell 100, which is beneficial to improving the preparation yield of the battery cell 10.

[0122] See Figure 5, in some embodiments, the multiple negative electrode plates 240 include a first negative electrode plate 240a. The second surface 202 is one surface of the first negative electrode plate 240a, and the third portion 330 is attached to the first negative electrode plate 240a. The first negative electrode plate 240a includes a first negative current collector (not shown in the figure), and the thickness of the first negative current collector is less than the thickness of the negative current collectors of the other negative electrode plates 240.

[0123] In the current solution of separately providing the bottom adhesive and the side adhesive on the electrode assembly 200, there is a gap between the bottom adhesive and the side adhesive on the bottom surface of the electrode assembly 200, and a part of the negative electrode plate 240 at the bottom of the electrode assembly 200 is exposed. When the battery cell 10 is stressed, the negative electrode plate 240 is easily stressed, causing the negative current collector to tear, and then problems such as metal ion precipitation occur. In the present application, the third portion 330 of the insulating adhesive tape 300 covers the second surface 202 of the electrode assembly 200 along the width direction Y of the electrode assembly. When the battery cell 10 is stressed, the insulating adhesive tape 300 on the first negative electrode plate 240a can play a buffering role, reducing the possibility of the first negative electrode plate 240a tearing. Thus, the thickness of the first negative current collector can be made smaller, so that along the thickness direction X of the electrode assembly, there is more space in the outer shell 100 for accommodating the active material, which is beneficial to improving the energy density of the battery cell 10.

[0124] In some embodiments, the thickness of the first negative current collector is H5, satisfying 4μm ≤ H5 ≤ 25μm. For example, H5 can be 4μm, 10μm, 15μm, 20μm, 25μm, etc.

[0125] When the thickness H5 of the first negative current collector is greater than or equal to 4μm, the first negative current collector can have a relatively large bearing capacity for the first negative active material layer of the first negative electrode plate 240a and is not easily broken; when the thickness H5 of the first negative current collector is less than or equal to 25μm, along the thickness direction X of the electrode assembly, there is more space in the outer shell 100 for accommodating the active material, which is beneficial to improving the energy density of the battery cell 10; therefore, when the thickness H5 of the first negative current collector satisfies 4μm ≤ H5 ≤ 25μm, the first negative current collector can not only have a relatively large bearing capacity for the first negative active material layer of the first negative electrode plate 240a and is not easily broken, but also along the thickness direction X of the electrode assembly, there is more space in the outer shell 100 for accommodating the active material, which is beneficial to improving the energy density of the battery cell 10.

[0126] In some embodiments, the outer shell 100 is a steel shell.

[0127] By making the outer shell 100 a steel shell, the stress-bearing performance of the outer shell 100 can be stronger, and the protection effect on the electrode assembly 200 is better.

[0128] See Figure 2 and Figure 3 In some embodiments, the battery cell 10 further includes a protective adhesive tape 410 attached to the positive electrode tab 210 and the negative electrode tab 220. Along the thickness direction X of the electrode assembly, the projection of the protective adhesive tape 410 does not overlap with the projection of the insulating adhesive tape 300. This enables the protective adhesive tape 410 to protect the positive electrode tab 210 and the negative electrode tab 220, and has a relatively small impact on the thickness of the electrode assembly 200.

[0129] In some other embodiments, along the thickness direction X of the electrode assembly, the projection of the protective adhesive tape 410 partially overlaps with the projection of the insulating adhesive tape 300. The electrode assembly 200 includes a first electrode tab, and a first surface 201 is one surface of the first electrode tab. The first part 310 and the fifth part 350 of the insulating adhesive tape 300 are attached to the first electrode tab. The first electrode tab includes a first coating area and a second coating area. The second coating area connects the first coating area and the positive electrode tab 210 (or the negative electrode tab 220). Along the thickness direction X of the electrode assembly, the projection of the second coating area overlaps with the projection of the protective adhesive tape 410, and the thickness of the second coating area is less than the thickness of the first coating area.

[0130] This enables the protective adhesive tape 410 to protect the positive electrode tab 210, the negative electrode tab 220, and part of the electrode assembly 200, and has a relatively small impact on the thickness of the electrode assembly 200.

[0131] In some embodiments, the battery cell 10 includes two protective adhesive tapes 410, which are respectively attached to both sides of the positive electrode tab 210 and the negative electrode tab 220 along the thickness direction X of the electrode assembly. This can further reduce the possibility of contact or interference between the positive electrode tab 210 and the negative electrode tab 220 and other components, and has a better protective effect on the positive electrode tab 210 and the negative electrode tab 220.

[0132] In some embodiments, the side wall 112 of the housing 110 includes a third side wall 112c and a fourth side wall 112d that are oppositely arranged along the length direction of the battery cell 10. The battery cell 10 includes an electrode terminal 420, and the electrode terminal 420 is disposed on the third side wall 112c and is insulatedly connected to the third side wall 112c. The positive electrode tab 210 is connected to the electrode terminal 420, and the negative electrode tab 220 is connected to the third side wall 112c. Since the width of the outer shell 100 is small, it is not convenient to provide two electrode terminals 420 on the third side wall 112c, and the distance between the two electrode terminals 420 is too close, which is likely to cause a short circuit. The embodiments of the present application can reduce the manufacturing difficulty of the battery cell 10 and can reduce the risk of short circuit of the battery cell 10.

[0133] In some embodiments, a liquid injection hole 102 is further provided at one end of the first side wall 112a close to the third side wall 112c. After the electrolyte is injected into the outer shell 100 through the liquid injection hole 102, it can infiltrate the electrode assembly 200 through the space reserved for the positive electrode tab 210 and the negative electrode tab 220 in the outer shell 100, which is beneficial to improving the infiltration speed and effect of the electrolyte.

[0134] An embodiment of the present application provides an electrical device, including the battery cell 10 of any of the above solutions, and the battery cell 10 is used to provide electrical energy for the electrical device.

[0135] The electrical device may be any of the foregoing devices or systems applying the battery cell 10.

[0136] Test for the defective rate of adhesive tape bonding: A total of 100 battery cells are taken, and the surface of the electrode assembly is observed visually to check for wrinkles and bubbles.

[0137] The following further describes in detail the characteristics and performance of the battery cell of the present application in conjunction with embodiments.

[0138] Referring to Table 1, in Table 1, L1 is the length of the electrode assembly, L1 = 200 mm; W1 is the width of the electrode assembly, W1 = 20 mm; L2 is the length of the insulating adhesive tape along the length direction of the electrode assembly; W2 is the width of the insulating adhesive tape along the width direction of the electrode assembly.

[0139] Table 1 Test of the drop passing rate and space utilization rate of the battery cell

[0140]

[0141] Test method for the drop passing rate of the battery cell:

[0142] 1. Fully charge the finished battery cell, then install it in a fixture, and drop the battery cell from a height of 1.5 m. Each of the six faces of the battery cell is dropped 6 times. 10 battery cells are tested in each group, and each group is tested 3 times repeatedly.

[0143] 2. Test the change in the open-circuit voltage of the battery cell before and after dropping and whether the battery cell catches fire or burns. Record the battery cells with voltage drop and fire as failed.

[0144] Test method for the space utilization rate of the battery cell:

[0145] 1. Measure the maximum thickness of the electrode assembly (including the thickness of the insulating adhesive tape) as H, and the inner cavity height of the outer shell as H0;

[0146] 2. The space utilization rate of the battery cell = (H / H0) * 100%.

[0147] The following conclusions can be obtained according to Table 1:

[0148] 1. Referring to Embodiments 1-5, when the length of the insulating adhesive tape is less than 100 mm or L2 / L1 is less than 50%, the coverage area of the insulating adhesive tape on the electrode assembly is small, and the drop passing rate of the battery cell is low; when the length of the insulating adhesive tape is greater than 160 mm or L2 / L1 is greater than 80%, the insulating adhesive tape may overlap with other components on the electrode assembly, resulting in a relatively large overall thickness of the electrode assembly and the insulating adhesive tape, which affects the space utilization rate inside the outer shell of the battery cell; when 100 mm ≤ L2 ≤ 160 mm or 50% ≤ L2 / L1 ≤ 80%, it can not only provide good protection for the electrode assembly by the insulating adhesive tape, resulting in a high drop passing rate of the battery cell, but also make the overall thickness of the electrode assembly and the insulating adhesive tape small, and the space utilization rate inside the outer shell of the battery cell high.

[0149] 2. Referring to Embodiments 3-8, when the width of the insulating adhesive tape is less than 30 mm or W2 / W1 is less than 1.5, the coverage areas of the first part and the fifth part of the insulating adhesive tape on the first surface are small, and the drop passing rate of the battery cell is low; when the width of the insulating adhesive tape is greater than 30 mm or W2 / W1 is greater than 1.5, the coverage areas of the first part and the fifth part of the insulating adhesive tape on the first surface are large, and the drop passing rate of the battery cell is high.

[0150] Referring to Table 2, W1 in Table 2 is the width of the electrode assembly.

[0151] Table 2 Probability Test of the Appearance of Wrinkles on the Insulating Adhesive Tape

[0152] W1 (mm) Probability of wrinkling Comparative Example 1 42 33％ Comparative Example 2 50 35％ Example 9 40 10％ Example 10 30 9％ Example 11 20 5

[0153] In the tests corresponding to Table 2, in Comparative Examples 1 and 2 and Embodiments 9-11, the integrally formed insulating adhesive tape is directly attached to the outer surface of the battery assembly.

[0154] It can be seen from Table 2 that when the width W1 of the electrode assembly is less than or equal to 40 mm, the situation of poor adhesion (i.e., the appearance of wrinkles) occurs less frequently when using the integrally formed insulating adhesive tape.

[0155] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0156] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: shell; An electrode assembly is arranged in the housing, the electrode assembly comprises a first surface and a second surface opposite to each other along the thickness direction thereof, and a third surface and a fourth surface opposite to each other along the width direction thereof; the electrode assembly comprises a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab are arranged at the same end in the length direction of the electrode assembly, or are respectively arranged at two ends in the length direction of the electrode assembly; the width W1 of the electrode assembly is less than or equal to 40 mm; The insulating tape comprises a first part, a second part, a third part, a fourth part and a fifth part which are integrally formed, wherein the first part is attached to the first surface; The second part is attached to the third surface and connected to the first part; The third part is attached to the second surface and connected to the second part; the fourth part is attached to the fourth surface and connected to the third part; the fifth part is attached to the first surface and connected to the fourth part.

2. The battery cell according to claim 1, characterized in that: The length of the electrode assembly is L1, and the thickness of the electrode assembly is H, satisfying L1>W1, L1>H, and W1≤20mm.

3. The battery cell according to claim 1, characterized in that: Along the length direction of the electrode assembly, the length of the electrode assembly is L1, the length of the insulating tape is L2, and 50%≤L2 / L1≤80% is satisfied; Along the width direction of the electrode assembly, the width of the insulating tape after unfolding is W2, satisfying 1.5≤W2 / W1≤2.

4. The battery cell according to claim 1, characterized in that: Along the length direction of the electrode assembly, the length of the insulating tape is L2, satisfying 100mm≤L2≤160mm; Along the width direction of the electrode assembly, the width of the insulating tape after unfolding is W2, satisfying 30mm≤W2≤60mm.

5. The battery cell according to claim 1, characterized in that: Along the thickness direction of the electrode assembly, a projection of the first portion does not overlap with a projection of the fifth portion.

6. The battery cell according to claim 5, characterized in that: The first portion and the fifth portion are spaced apart from each other along a width direction of the electrode assembly.

7. The battery cell according to claim 1, characterized in that: At least a portion of the insulating tape is bonded to the housing.

8. The battery cell according to claim 7, characterized in that: The insulating tape includes a base layer, a first adhesive layer and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively arranged on both sides of the base layer along its thickness direction. The first adhesive layer is bonded to the electrode assembly, and the second adhesive layer is bonded to the shell.

9. The battery cell according to claim 8, characterized in that: The thickness of the insulating tape is H1, satisfying 0.01 mm≤H1≤0.1 mm.

10. The battery cell according to claim 8, characterized in that: The thickness of the base layer is H2, the thickness of the first adhesive layer is H3, and the thickness of the second adhesive layer is H4, satisfying 0.2≤(H3 / H2)≤2.5 and 0.2≤(H4 / H2)≤2.

5.

11. The battery cell according to claim 8, characterized in that: The melting point of the base layer is T, which satisfies 150°C≤T≤300°C.

12. The battery cell according to claim 8, characterized in that: The bonding force of the first bonding layer is F1, F1 ≥ 0.1 N / mm; The adhesive force of the second adhesive layer is F2, and F2≥0.1 N / mm.

13. The battery cell according to claim 7, characterized in that: The shell includes a shell and a shell cover, the shell includes a bottom wall and a side wall surrounding the bottom wall, one end of the side wall is connected to the bottom wall, the other end of the side wall forms an opening, the shell cover is connected to the side wall and covers the opening, and the shell cover and the bottom wall are arranged opposite to each other along the thickness direction of the electrode assembly; The first part and the fifth part are both bonded to the shell cover, and the third part is bonded to the bottom wall.

14. The battery cell according to claim 13, characterized in that: The side wall includes a first side wall and a second side wall which are arranged opposite to each other along the width direction of the battery core, and the second portion is bonded to the first side wall, or the fourth portion is bonded to the second side wall.

15. The battery cell according to claim 1, characterized in that: The electrode assembly is a laminated structure, and includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked along a thickness direction thereof.

16. The battery cell according to claim 15, characterized in that: The plurality of negative electrode sheets include a first negative electrode sheet, the second surface is a surface of the first negative electrode sheet, and the third portion is attached to the first negative electrode sheet; The first negative electrode sheet includes a first negative electrode collector, and the thickness of the first negative electrode collector is smaller than the thickness of the negative electrode collectors of other negative electrode sheets.

17. The battery cell according to claim 16, characterized in that: The thickness of the first negative electrode current collector is H5, satisfying 4 μm≤H5≤25 μm.

18. The battery cell according to claim 1, characterized in that: The shell is a steel shell.

19. An electrical equipment, characterized in that: The battery cell comprises a battery cell as claimed in any one of claims 1 to 18, wherein the battery cell is used to provide electrical energy.

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