Electrochemical device and electricity-using device

Abstract

The present application discloses an electrochemical device and an electrical device, wherein the electrochemical device comprises a first shell, a second shell, a first separator, a first electrode assembly and a second electrode assembly. The first separator is located between the first shell and the second shell. A first cavity is provided between the first shell and the first separator, and a second cavity is provided between the second shell and the first separator. The first electrode assembly is provided in the first cavity, and the second electrode assembly is provided in the second cavity. The electrochemical device comprises a first sealing portion, the first sealing portion comprises a first outer edge, the first separator comprises a first sealing area located in the first sealing portion, the first sealing area comprises a first region and a second region, the first region is away from the first outer edge relative to the second region, the packaging strength between the first region and the first shell is F1, the packaging strength between the second region and the first shell is F2, and F2>F1. By the above manner, the packaging reliability of the electrochemical device can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an electrochemical device and an electrical device. Background Art

[0002] At present, batteries are widely used in electronic products such as mobile phones, tablets, and laptops. Because in some application scenarios, a single battery cell cannot achieve the desired power output; therefore, multiple battery cells are usually connected in series, in parallel, or in hybrid connection, so that the multiple battery cells work together to achieve the desired power output. However, although connecting multiple battery cells in series, in parallel, or in hybrid connection can increase the output power, the energy density of the entire battery pack is low. Therefore, the design of same-bag series / parallel batteries is proposed. The same-bag series / parallel batteries include a shell and a plurality of electrode assemblies arranged in the same shell, and the series / parallel electrode assemblies can be separated by an isolator. However, due to the presence of multiple electrode assemblies inside this type of battery, the packaging reliability is still subject to severe challenges during impacts such as falling. Summary of the invention

[0003] In view of the above problems, the present application provides an electrochemical device and an electrical device to improve the packaging reliability of batteries connected in series or in parallel in the same bag.

[0004] According to one aspect of the present application, an electrochemical device is provided, which includes a first shell, a second shell, a first separator, a first electrode assembly, and a second electrode assembly. The first separator is located between the first shell and the second shell, the electrochemical device is provided with a first cavity between the first shell and the first separator, the electrochemical device is provided with a second cavity between the second shell and the first separator, the first electrode assembly is provided in the first cavity, the second electrode assembly is provided in the second cavity, the electrochemical device includes a first sealing portion, the first sealing portion includes a first outer edge, the first separator includes a first sealing area located in the first sealing portion, the first sealing area includes a first region and a second region, along the width direction of the first sealing area, the first region is away from the first outer edge relative to the second region, the packaging strength between the first region and the first shell is F1, the packaging strength between the second region and the first shell is F2, and F2>F1 is satisfied. By satisfying F2>F1, during an impact such as falling of the electrochemical device, the weaker connection between the first region and the first shell can provide a buffering effect for the first sealing portion, and the detachment of the connection between the first region and the first shell can dissipate part of the impact kinetic energy received by the first sealing portion, thereby reducing the risk of the first sealing portion being broken and improving the packaging reliability of the electrochemical device.

[0005] In an optional manner, F2≥2F1. In an optional manner, F2-F1≥5N / 8mm. In this case, the connection strength between the second region and the first shell can be significantly greater than the connection strength between the first region and the first shell. Even if the connection between the first region and the first shell fails after being impacted, the failure of the connection between the second region and the first shell can still be effectively suppressed, thereby improving the packaging reliability of the electrochemical device.

[0006] In an optional manner, F1≥5N / 8mm. In an optional manner, F2≥15N / 8mm. In this case, the first region and the first shell, as well as the second region and the first shell, have good connection strength, which can effectively suppress the failure of the connection after being impacted, and improve the packaging reliability of the electrochemical device.

[0007] In an optional manner, the packaging strength between the first region and the second shell is F3, and the packaging strength between the second region and the second shell is F4, satisfying F4>F3. In an optional manner, the electrochemical device also includes a second separator located between the first separator and the second shell, and the packaging strength between the first region and the second separator is S1, and the packaging strength between the second region and the second separator is S2, satisfying S2>S1. At this time, there are buffer areas on both sides of the connection of the first separator, which can provide good buffering effect for impacts from different sides, thereby further improving the packaging reliability of the electrochemical device.

[0008] In an optional manner, the electrochemical device further includes a second isolating member located between the first isolating member and the second shell, the second isolating member includes a second sealing area located in the first sealing portion, the second sealing area includes a third area and a fourth area, along the width direction of the second sealing area, the third area is away from the first outer edge relative to the fourth area; the packaging strength between the third area and the second shell is F5, and the packaging strength between the fourth area and the second shell is F6, satisfying F6>F5. At this time, there is also a buffer area in the connection between the second shell and the second isolating member, which can reduce the risk of connection failure between the two, thereby further improving the packaging reliability of the electrochemical device.

[0009] In an optional manner, the electrochemical device satisfies at least one of the following conditions: (a) F4≥2F3; (b) F4-F3≥5N / 8mm; (c) F3≥5N / 8mm; (d) F4≥15N / 8mm.

[0010] In an optional manner, the electrochemical device satisfies at least one of the following conditions: (e) S2≥2S1; (f) S2-S1≥5N / 8mm; (g) S1≥5N / 8mm; (h) S2≥15N / 8mm.

[0011] In an optional manner, the electrochemical device satisfies at least one of the following conditions: (a) F6≥2F5; (b) F6-F5≥5N / 8mm; (c) F5≥5N / 8mm; (d) F6≥15N / 8mm.

[0012] In an optional manner, along the width direction of the first sealing area, the width of the first area is D1, and the width of the second area is D2, satisfying: D1 ≥ 0.5 mm, and / or D2 ≥ 0.5 mm. In this case, more impact kinetic energy can be dissipated by the detachment of the connection between the first area and the first shell, thereby further improving the packaging reliability of the electrochemical device.

[0013] In an optional manner, along the width direction of the second sealing area, the width of the third area is D3, and the width of the fourth area is D4, satisfying: D3 ≥ 0.5 mm, and / or D4 ≥ 0.5 mm. In this case, more impact kinetic energy can be dissipated by the detachment of the connection between the third area and the second shell, thereby further improving the packaging reliability of the electrochemical device.

[0014] In an optional embodiment, the electrochemical device includes a pole tab module, the pole tab module includes a first pole tab and a second pole tab, one end of the first pole tab is connected to the first electrode assembly, one end of the second pole tab is connected to the second electrode assembly, and the other ends of the first pole tab and the second pole tab both extend from the first sealing portion.

[0015] In an optional manner, the first electrode assembly and the second electrode assembly are connected in series.

[0016] In an optional manner, the first isolation member and / or the second isolation member includes a substrate layer and an encapsulation layer located on the surface of the substrate layer, and the material of the substrate layer includes at least one of metal, carbon material or a first polymer; the material of the encapsulation layer includes a second polymer.

[0017] In an optional embodiment, the metal used as the substrate layer material includes at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, In, Zn, stainless steel and their combinations or alloys.

[0018] In an optional manner, the carbon material used as the substrate layer material includes at least one of carbon felt, carbon film, carbon black, acetylene black, fullerene, conductive graphite film or graphene film.

[0019] In an optional embodiment, the first polymer used as the material of the substrate layer includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-propylene copolymer, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polyester, polysulfone, amorphous α-olefin copolymer or at least one of the derivatives of the above substances.

[0020] In an optional manner, the second polymer used as the encapsulation layer material includes: polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-propylene copolymer, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyamide, polyester, amorphous α-olefin copolymer or at least one of the derivatives of the above substances.

[0021] According to another aspect of the present application, an electrical device is provided, which includes the above-mentioned electrochemical device.

[0022] The beneficial effect of the present application is that, different from the prior art, the present application sets the packaging strength F1 between the first region and the first shell to be greater than the packaging strength F2 between the second region and the first shell. During the impact of falling or other impacts on the electrochemical device, the weaker connection between the first region and the first shell can provide a buffering effect for the first sealing part, and the detachment of the connection between the first region and the first shell can dissipate part of the impact kinetic energy received by the first sealing part, thereby reducing the risk of the first sealing part being broken and improving the packaging reliability of the electrochemical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the following is a brief introduction to the drawings required for describing the specific embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0024] Figure 1 is a schematic diagram of the overall structure of the electrochemical device of an embodiment of the present application;

[0025] Figure 2It is a schematic diagram of an exploded perspective view of the overall structure of the electrochemical device according to an embodiment of the present application;

[0026] Figure 3 It is a schematic diagram of the overall structure of the electrochemical device of the embodiment of the present application exploded from another angle;

[0027] Figure 4 is an exploded schematic diagram of the overall structure of another embodiment of the electrochemical device of the present application;

[0028] Figure 5 is an exploded schematic diagram of the overall structure of another embodiment of the electrochemical device of the present application;

[0029] Figure 6 is a schematic diagram of the side structure of the housing and the first isolation member of the electrochemical device according to an embodiment of the present application;

[0030] Figure 7 yes Figure 1 Middle AA section cutaway view;

[0031] Figure 8 yes Figure 7 A magnified schematic diagram of the structure at B in the middle;

[0032] Fig. 9 is a schematic diagram of an angle of a first isolation member of an electrochemical device according to an embodiment of the present application;

[0033] Fig.10 is a schematic diagram of an angle of a second isolation member of an electrochemical device according to an embodiment of the present application;

[0034] Fig.11 It is a schematic diagram of the structure of the electrical device according to the embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0037] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0038] See also Figure 1-Figure 3 and Figure 8 The electrochemical device 1 includes a first shell 100, a second shell 200, a first separator 300, a first electrode assembly 400 and a second electrode assembly 500. The first shell 100 and the second shell 200 are enclosed together to form the outer shell of the electrochemical device 1. The first separator 300 is arranged between the first shell 100 and the second shell 200. The electrochemical device 1 is provided with a first cavity 101 and a second cavity 102 on both sides of the first separator 300, respectively. The first electrode assembly 400 is arranged in the above-mentioned first cavity 101, and the second electrode assembly 500 is arranged in the above-mentioned second cavity 102. The electrochemical device 1 includes a first sealing portion 600, which is formed by the mutual connection between the first shell 100, the second shell 200 and the first separator 300.

[0039] like Figure 4 and Figure 5 As shown, the electrochemical device further includes a second separator 700, which is disposed between the first separator 300 and the second shell 200. At this time, the first seal 600 is formed by the first shell 100, the second shell 200, the first separator 300 and the second separator 700. In order to better understand the specific structure of the electrochemical device 1, the first shell 100, the second shell 200, the first separator 300, the first electrode assembly 400, the second electrode assembly 500, the second separator 700 and the first seal 600 are specifically described below.

[0040] For the first shell 100 and the second shell 200, as Figure 2 and Figure 3As shown, the first shell 100 and the second shell 200 are arranged relative to each other along the first preset direction X shown in the figure, and a receiving space is defined between the two. The first shell 100 is a box-shaped structure as a whole, which includes a first cavity portion 110 and a first peripheral portion 120. Among them, the first cavity portion 110 is recessed toward the side away from the second shell 200 to form a concave cavity. Specifically, the first cavity portion 110 includes a first bottom wall and a first side wall extending from the edge of the first bottom wall along the above-mentioned first preset direction X, and the first bottom wall and the first side wall together enclose the above-mentioned concave cavity; the concave cavity of the first cavity portion 110 is arranged toward the second shell 200. The first peripheral portion 120 is a thin sheet structure, which is arranged around the first cavity portion 110; the first peripheral portion 120 extends outward from the open end of the first cavity portion 110. Similarly, the second shell 200 is also a box-shaped structure as a whole, which includes a second cavity portion 210 and a second peripheral portion 220. The second cavity portion 210 is recessed toward the side away from the first shell 100 to form a concave cavity. In this embodiment, the second cavity portion 210 includes a second bottom wall and a second side wall extending from the edge of the second bottom wall along the first preset direction X, and the second bottom wall and the second side wall together enclose the concave cavity of the second cavity portion 210; the concave cavity of the second cavity portion 210 is arranged toward the first shell 100. The second peripheral portion 220 is a thin sheet-like structure, which is arranged around the second cavity portion 210; the second peripheral portion 220 extends outward from the open end of the second cavity portion 210. In this embodiment, the first shell 100 and the second shell 200 are two independent structures, and the concave cavities of the first cavity portion 110 and the second cavity portion 210 are respectively formed by stamping, and the first shell 100 and the second shell 200 are respectively fixed to the above-mentioned first isolation member 300. It is understandable that in other embodiments of the present application, the first shell 100 and the second shell 200 may also be integrally formed; specifically, the same sheet-like structure is folded after two concave cavities are punched out to form the above-mentioned first shell 100 and second shell 200 that are relatively arranged.

[0041] As for the materials of the first housing 100 and the second housing 200, there are actually various materials. Figure 6As shown, in this embodiment, the first shell 100 includes a first insulating material layer 130, a first metal layer 140 and a second insulating material layer 150 which are stacked. Along the thickness direction of the sheet of the first shell 100, the first metal layer 140 is arranged between the first insulating material layer 130 and the second insulating material layer 150, and the second insulating material layer 150 is arranged facing the first isolation member 300. Optionally, the material of the first metal layer 140 includes aluminum, and the material of the first insulating material layer 130 and / or the second insulating material layer 150 includes polypropylene; of course, other embodiments of the present application can also make adaptive deformations on this basis, for example, the first metal layer 140 includes materials such as aluminum alloy and copper alloy, and the first insulating material layer 130 and / or the second insulating material layer 150 include at least one of modified polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer. The second shell 200 includes a third insulating material layer 230, a second metal layer 240 and a fourth insulating material layer 250. Along the thickness direction of the sheet material of the second shell 200, the second metal layer 240 is arranged between the third insulating material layer 230 and the fourth insulating material layer 250, and the fourth insulating material layer 250 is arranged facing the first isolation piece 300. The material selection of the second shell 200 is basically the same as that of the first shell 100, which will not be described in detail here.

[0042] For the first isolation member 300, Figure 7 and Figure 8 As shown, the first isolating member 300 is disposed between the first shell 100 and the second shell 200, so that the first isolating member 300 separates the receiving space surrounded by the first shell 100 and the second shell 200, thereby forming a first cavity 101 and a second cavity 102 respectively located on both sides of the first isolating member 300 along the thickness direction; that is, the electrochemical device 1 is provided with the first cavity 101 and the second cavity 102 respectively on both sides of the first isolating member 300. The first isolating member 300 and the first shell 100 together surround the first cavity 101, and the first isolating member 300 and the second shell 200 together surround the second cavity 102. For details, please refer to Figure 2 and Figure 3 The first isolation member 300 is a thin sheet structure, which includes a first isolation area 301 and a first sealing area 302. The first isolation area 301 is accommodated in the above-mentioned receiving space, and is arranged opposite to the above-mentioned first cavity portion 110. The first sealing area 302 is arranged around the first isolation area 301, and is located between the above-mentioned first peripheral portion 120 and the second peripheral portion 220; the first sealing area 302 is fixedly connected to the first peripheral portion 120 of the first shell 100, and the two can be fixed by at least one of the fixing methods such as hot melt or glue.

[0043] In some embodiments, the first isolation member 300 includes a first surface (not labeled) and a second surface (not labeled) arranged opposite to the first surface, the first surface is located on a side close to the first shell 100, and the second surface is located on a side close to the second shell 200.

[0044] In some embodiments, Fig. 9 As shown, the first sealing area 302 includes a first area 302a and a second area 302b. Along the width direction of the first sealing area 302, the first area 302a is away from the first outer edge of the first sealing portion 600 relative to the second area 302b. The packaging strength between the first area 302a and the first shell 100 is F1, that is, the packaging strength between the first surface on the first area 302a and the first shell 100 is F1, and the packaging strength between the second area 302b and the first shell 100 is F2, that is, the packaging strength between the first surface on the second area 302b and the first shell 100 is F2, and F2>F1 is satisfied. By satisfying F2>F1, during the impact of falling or other impacts on the electrochemical device 1, the weaker connection between the first region 302a and the first shell 100 can provide a buffering effect for the first sealing portion 600, and the detachment of the connection between the first region 302a and the first shell 100 can dissipate part of the impact kinetic energy received by the first sealing portion 600, thereby reducing the risk of the first sealing portion 600 being broken and improving the packaging reliability of the electrochemical device 1.

[0045] Optionally, the first region 302a and the first shell 100 are fixed by hot melt, and the second region 302b and the first shell 100 are fixed by hot melt or glue. In this way, when the second region 302b and the first shell 100 are fixed by glue, the effect of glue entering the interior of the first shell 100 and causing damage to the first electrode assembly 400 can be reduced.

[0046] In some embodiments, the following conditions are satisfied: F2 ≥ 2F1, and / or, F2-F1 ≥ 5N / 8mm. In this case, the connection strength between the second region 302b and the first shell 100 can be significantly greater than the connection strength between the first region 302a and the first shell 100. Even if the connection between the first region 302a and the first shell 100 fails after being impacted, the failure of the connection between the second region 302b and the first shell 100 can still be effectively suppressed, thereby improving the packaging reliability of the electrochemical device 1.

[0047] In some embodiments, the following conditions are satisfied: F1 ≥ 5N / 8mm, and / or F2 ≥ 15N / 8mm. At this time, the first region 302a and the first shell 100 and the second region 302a and the first shell 100 have good connection strength, which can effectively suppress the failure of the connection after being impacted, and improve the packaging reliability of the electrochemical device 1.

[0048] In some embodiments, please refer to Fig. 9 , along the width direction of the first sealing area 302, the width of the first area 302a is D1, and satisfies: D1 ≥ 0.5 mm. At this time, more impact kinetic energy can be dissipated by the disconnection between the first area 302a and the first shell 100, thereby further improving the packaging reliability of the electrochemical device 1.

[0049] In some embodiments, along the width direction of the first sealing area 302, the width of the second area 302b is D2, and satisfies: D2 ≥ 0.5 mm. At this time, there is a sufficient connection width between the second area 302b and the first shell 100, which can prevent the connection between the two from falling off, thereby further improving the packaging reliability of the electrochemical device 1.

[0050] In some embodiments, the packaging strength between the first region 302a and the second shell 200 is F3, that is, the packaging strength between the second surface on the first region 302a and the second shell 200 is F3, and the packaging strength between the second region 302b and the second shell 200 is F4, that is, the packaging strength between the second surface on the second region 302b and the second shell 200 is F4, and F4>F3 is satisfied. At this time, there is also a buffer area in the connection between the second shell 200 and the first isolation member 300, which can reduce the risk of connection failure between the two, thereby further improving the packaging reliability of the electrochemical device 1.

[0051] Optionally, the first region 302a and the second shell 200 are fixed by hot melt, and the second region 302b and the second shell 200 are fixed by hot melt or glue. In this way, when the second region 302b and the second shell 200 are fixed by glue, the effect of glue entering the second shell 200 and causing damage to the second electrode assembly 500 can be reduced.

[0052] In some embodiments, the following conditions are satisfied: F4 ≥ 2F3, and / or, F4-F3 ≥ 5N / 8mm. In this case, the connection strength between the second region 302b and the second shell 200 can be significantly greater than the connection strength between the first region 302a and the second shell 200. Even if the connection between the first region 302a and the second shell 200 fails after being impacted, the failure of the connection between the second region 302b and the second shell 200 can still be effectively suppressed, thereby improving the packaging reliability of the electrochemical device 1.

[0053] In some embodiments, the following conditions are satisfied: F3 ≥ 5N / 8mm, and / or F4 ≥ 15N / 8mm. At this time, the first region 302a and the second shell 200 and the second region 302a and the second shell 200 have good connection strength, which can effectively suppress the failure of the connection after being impacted, and improve the packaging reliability of the electrochemical device 1.

[0054] It should be noted that the "packaging strength" mentioned in this application document means the maximum force required to peel off two interconnected components from the connection interface per unit width. For example, 10.5N / 8mm means that when the width of the bonding surface of the two components is 8mm, the maximum force required to separate the two components along the direction perpendicular to the width direction of the bonding surface is 10.5N.

[0055] For the second isolating member 700, Figure 4 and Figure 5 As shown, the second isolating member 700 is located between the first isolating member 300 and the second shell 200. Specifically, the second isolating member 700 is a thin sheet structure, which includes a second isolating area 701 and a second sealing area 702, and the second sealing area 702 is located in the first sealing part 600. Among them, the second isolating area 701 is accommodated in the above-mentioned receiving space, and is arranged opposite to the above-mentioned second cavity part 210, and the second isolating area 701 is recessed toward the side close to the second shell 200 to form another concave cavity, which can be used to place another electrode assembly in addition to the first electrode assembly 400 and the second electrode assembly 500. The second sealing area 702 is arranged around the second isolating area 701, and is located between the above-mentioned first sealing area 302 and the second peripheral portion 220; the second sealing area 702 is fixedly connected to the second peripheral portion 220 of the second shell 200 and the first sealing area 302, and the three can be fixed by at least one of the fixing methods such as hot melt or glue.

[0056] In some embodiments, the second isolation member 700 includes a third surface and a fourth surface disposed opposite to the third surface, the third surface is located on a side close to the first shell 100 , and the fourth surface is located on a side close to the second shell 200 .

[0057] In some embodiments, the second sealing area 702 includes a third area 702a and a fourth area 702b. Along the width direction of the second sealing area 702, the third area 702a is away from the first outer edge of the first sealing portion 600 relative to the fourth area 702b. The packaging strength between the third area 702a and the second shell 200 is F5, that is, the packaging strength between the fourth surface on the third area 702a and the second shell 200 is F5, and the packaging strength between the fourth area 702b and the second shell 200 is F6, that is, the packaging strength between the fourth surface on the fourth area 702b and the second shell 200 is F6, and F6>F5 is satisfied.

[0058] Optionally, the third region 702a and the second shell 200 are fixed by hot melt, and the fourth region 702b and the second shell 200 are fixed by hot melt or glue. In this way, when the fourth region 702b and the second shell 200 are fixed by glue, the effect of glue entering the interior of the second shell 200 and causing damage to the second electrode assembly 500 can be reduced.

[0059] In some embodiments, the following conditions are satisfied: F6 ≥ 2F5, and / or, F6 - F5 ≥ 5N / 8mm.

[0060] In some embodiments, the following conditions are satisfied: F5 ≥ 5N / 8mm, and / or, F6 ≥ 15N / 8mm.

[0061] In some embodiments, please refer to Fig.10 , along the width direction of the second sealing area 702, the width of the third area 702a is D3, and satisfies: D3 ≥ 0.5mm. At this time, more impact kinetic energy can be dissipated by the disconnection between the third area 702a and the second shell 200, thereby further improving the packaging reliability of the electrochemical device 1.

[0062] In some embodiments, the width of the fourth region 702b is D4 along the width direction of the second sealing area 702, and satisfies: D4 ≥ 0.5 mm. At this time, there is a sufficient connection width between the fourth region 702b and the second shell 200, which can prevent the connection between the two from falling off, thereby further improving the packaging reliability of the electrochemical device 1.

[0063] In addition, the second separator 700 is also connected to the first separator 300 to seal another electrode assembly between the second separator 700 and the first separator 300. In some embodiments, the packaging strength between the first region 302a and the second separator 700 is S1, that is, the packaging strength between the first region 302a and the third region 702a is S1, and the packaging strength between the second region 302b and the second separator 700 is S2, that is, the packaging strength between the second region 302b and the fourth region 702b is S2, and S2>S1 is satisfied. At this time, there are buffer areas on both sides of the connection of the first separator 300, which can provide good buffering for impacts from different sides, thereby further improving the packaging reliability of the electrochemical device 1.

[0064] Optionally, the first region 302a and the third region 702a are fixed by hot melt, and the second region 302b and the fourth region 702b are fixed by glue. In this way, when the second region 302b and the fourth region 702b are fixed by glue, the glue can be reduced from entering between the first insulating member 300 and the second insulating member 700, thereby reducing the impact on another electrode assembly located between the two.

[0065] In some embodiments, S2≥2S1, and / or S2-S1≥5N / 8mm. In some embodiments, S1≥5N / 8mm, and / or S2≥15N / 8mm.

[0066] In addition, the electrochemical device also includes a tab module 800. Figure 4 and Figure 5 As shown, the tab module 800 includes a first tab 810 and a second tab 820 . The first pole lug 810 includes two first sub-pole lugs. Among the first pole lug 810 connected to the first electrode assembly 400, one end of a first sub-pole lug is connected to the first pole piece of the first electrode assembly 400, and the other end extends out of the above-mentioned outer shell part through the hot melt area between the first shell 100 and the first insulating member 300. One end of the other first sub-pole lug is connected to the second pole piece of the first electrode assembly 400, and the other end extends out of the above-mentioned outer shell part through the hot melt area between the first shell 100 and the first insulating member 300. The second pole lug 820 includes two second sub-pole lugs. One end of a second sub-pole lug is connected to the first pole piece of the second electrode assembly 500, and the other end extends out of the above-mentioned outer shell part through the hot melt area between the second shell 200 and the first insulating member 300. One end of the other second sub-pole lug is connected to the second pole piece of the second electrode assembly 500, and the other end extends out of the above-mentioned outer shell part through the hot melt area between the second shell 200 and the first insulating member 300.

[0067] A first sub-electrode ear connected to the first electrode piece / the second electrode piece on the first electrode assembly 400 is electrically connected to a second sub-electrode ear connected to the second electrode piece / the first electrode piece on the second electrode assembly 500, so that the first electrode assembly 400 and the second electrode assembly 500 are connected in series. It can be understood that in other embodiments of the present application, the first electrode assembly 400 and the second electrode assembly 500 can also be connected in parallel.

[0068] In some embodiments, the first tab and the second tab are provided with tab glue, which can be connected to the first shell 100, the second shell or the first isolation member 300 by hot melting or other fixing methods to ensure the sealing of the first tab and the second tab. Optionally, the tab glue can be made of materials such as polypropylene.

[0069] For the first sealing portion 600, Figure 1-Figure 3 As shown, the first sealing portion 600 is formed by the connection between the first isolation member 300 and the first shell 100 and the second shell 200. Specifically, the first region 302a and the second region 302b are connected to the first peripheral portion of the first shell 100 to form a part of the first sealing portion 600, and the first region 302a and the second region 302b are connected to the second peripheral portion 220 of the second shell 200 to form another part of the first sealing portion 600.

[0070] In some embodiments, Figure 4 and Figure 5 As shown, the first seal part 600 is formed by the connection between the first isolating member 300, the second isolating member 700, the first shell 100 and the second shell 200. At this time, the first area 302a and the second area 302b are connected to the first peripheral edge of the first shell 100 to form a part of the first seal part 600, the first area 302a and the second area 302b are connected to the third area 702a and the fourth area 702b to form another part of the first seal part 600, and the third area 702a and the fourth area 702b are connected to the second peripheral edge 220 of the second shell 200 to form another part of the first seal part 600, and the three parts form a complete first seal part 600. Of course, it can be understood that the number of the first isolating member 300 and the second isolating member 700 is not limited to that described in the embodiment of the present application. When the number of the first isolating member 300 and the second isolating member 700 is multiple, the composition of the first seal part 600 is based on the above-mentioned structure composition and so on.

[0071] In addition, in order to help readers more clearly understand the technical effects brought about by the present technical solution, this application takes lithium-ion batteries as an example and conducts the following comparative tests.

[0072] Preparation of lithium-ion batteries

[0073] The electrode assembly is prepared in the following manner: (1) Preparation of negative electrode sheet: Mix the negative electrode active materials artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) in a weight ratio of 96:1.5:2.5, add deionized water, prepare a slurry with a solid content of 70wt%, and stir evenly. The slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 10μm, and dried at 110°C to obtain a negative electrode sheet with a coating thickness of 150μm and a single-sided coating of a negative electrode active material layer. Repeat the above steps on the other surface of the negative electrode current collector copper foil to obtain a negative electrode sheet with a double-sided coating of a negative electrode active material layer. Then, the negative electrode sheet is cut into a size of 41mm×61mm for standby use. (2) Preparation of positive electrode sheet: The positive electrode active material lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) is added to prepare a slurry with a solid content of 75wt%, and stirred evenly. The slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 12μm, and dried at 90°C to obtain a positive electrode sheet with a positive electrode active material layer thickness of 100μm. On the other surface of the positive electrode current collector aluminum foil, the above steps are repeated to obtain a positive electrode sheet coated with a positive electrode active material layer on both sides. Then, the positive electrode sheet is cut into a size of 38mm×58mm for standby use. (3) Preparation of electrode assembly: The separator, the double-sided coated negative electrode sheet, the separator, and the double-sided coated positive electrode sheet are stacked in sequence to form a laminate, and then the four corners of the entire laminate structure are fixed for standby use. Each electrode assembly includes a positive electrode tab and a negative electrode tab, and the separator is a polyethylene (PE) film with a thickness of 15 μm.

[0074] The electrolyte was prepared as follows: In a dry argon atmosphere, organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were first mixed in a mass ratio of EC:EMC:DEC=30:50:20, and then lithium salt lithium hexafluorophosphate (LiPF6) was added to the organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0075] The spacer was prepared in the following manner: (1) the encapsulation material PP in the encapsulation layer was uniformly dispersed in the dispersant NMP (N-methylpyrrolidone) to obtain an encapsulation layer suspension, the concentration of which was 45 wt%; (2) a coating machine was used to prepare an encapsulation layer PP with a thickness of 40 μm on both surfaces of the substrate layer A1 with a thickness of 20 μm. (3) the dispersant NMP in the encapsulation layer suspension was dried at 130°C, and the preparation of the spacer was completed.

[0076] Packaging method: When packaging lithium-ion batteries, the upper packaging bag aluminum-plastic film (first shell), the first electrode assembly, the first separator, the second electrode assembly, the second separator, another electrode assembly... and the lower packaging bag aluminum-plastic film (second shell) are stacked and placed. Among them, the first area is fixed to the first shell and the second shell by heat sealing, the third area is fixed to the first area and the second shell by heat sealing, the second area is fixed to the first shell and the second shell by glue sealing, and the fourth area is fixed to the second area and the second shell by glue sealing. After that, the lithium-ion battery is obtained through the processes of liquid injection, formation, degassing, etc.

[0077] Test of packaging strength: take a packaging area sample with a width of W1 (for example, W1 can be 8mm), use a multifunctional tensile tester, clamp the material on both sides of the sealing area, take a tensile speed of 50mm / min, and test to obtain the peeling tensile force P1, then the packaging strength F = P1 / W1.

[0078] High temperature and high humidity sealing test: Place the lithium-ion battery in an environment of 75°C and 90%-95% relative humidity for 7 days. If the battery does not leak, catch fire or explode, the test is passed.

[0079] Drop test method: Take 10 lithium-ion batteries and drop them freely from a height of 1.5m. If the seal is not broken, the test is passed. The number of lithium-ion batteries that pass the test is counted. The drop test pass rate = pass number / 10.

[0080] Example 1

[0081] The first region and the first shell are fixed by heat sealing, and the heat sealing area is set to A. The packaging strength of the heat sealing area A is F1=10N / 8mm, and the packaging width of the heat sealing area A is 0.8mm. The first region and the second shell are fixed by heat sealing, and the heat sealing area is set to B. The packaging strength of the heat sealing area B is F3=10N / 8mm, and the packaging width of the heat sealing area B is 0.8mm. The second region and the first shell are sealed with glue, and the glue sealing area is set to C. The packaging strength of the glue sealing area C is F2=35N / 8mm, and the packaging width of the glue sealing area C is 1.5mm. The second region and the second shell are sealed with glue, and the glue sealing area is set to D. The packaging strength of the glue sealing area D is F4=35N / 8mm, and the packaging width of the glue sealing area D is 1.5mm.

[0082] Example 2

[0083] The first region and the first shell are fixed by heat sealing, and the heat sealing area is set to A. The packaging strength of the heat sealing area A is F1=5N / 8mm, and the packaging width of the heat sealing area A is 0.5mm. The first region and the second shell are fixed by heat sealing, and the heat sealing area is set to B. The packaging strength of the heat sealing area B is F3=5N / 8mm, and the packaging width of the heat sealing area B is 0.5mm. The second region and the first shell are sealed with glue, and the glue sealing area is set to C. The packaging strength of the glue sealing area C is F2=15N / 8mm, and the packaging width of the glue sealing area C is 0.5mm. The second region and the second shell are sealed with glue, and the glue sealing area is set to D. The packaging strength of the glue sealing area D is F4=15N / 8mm, and the packaging width of the glue sealing area D is 0.5mm.

[0084] Example 3

[0085] The first region and the first shell are fixed by heat sealing, and the heat sealing area is set to A. The packaging strength of the heat sealing area A is F1=15N / 8mm, and the packaging width of the heat sealing area A is 1.2mm. The first region and the second shell are fixed by heat sealing, and the heat sealing area is set to B. The packaging strength of the heat sealing area B is F3=15N / 8mm, and the packaging width of the heat sealing area B is 1.2mm. The second region and the first shell are sealed with glue, and the glue sealing area is set to C. The packaging strength of the glue sealing area C is F2=30N / 8mm, and the packaging width of the glue sealing area C is 1.2mm. The second region and the second shell are sealed with glue, and the glue sealing area is set to D. The packaging strength of the glue sealing area D is F4=30N / 8mm, and the packaging width of the glue sealing area D is 1.2mm.

[0086] Comparative Example

[0087] The first sealing area and the first shell are fixed by heat sealing, and the heat sealing area is set to A. The packaging strength of the heat sealing area A is F1=15N / 8mm, and the packaging width of the heat sealing area A is 1.2mm. The first sealing area and the second shell are fixed by heat sealing, and the heat sealing area is set to B. The packaging strength of the heat sealing area B is F3=15N / 8mm, and the packaging width of the heat sealing area B is 1.2mm.

[0088] The test results are shown in Table 1 below:

[0089]

[0090] Table 1

[0091] It can be seen from the data in Table 1 that compared with the comparative example, the lithium-ion batteries in Examples 1-3 have better sealing and drop test pass rate. This is because, by satisfying F2>F1, on the one hand, in a high temperature and high humidity environment, the internal expansion stress can be buffered by the detachment of the connection between the first region and the first shell, thereby reducing the risk of leakage of the seal; on the other hand, during impact such as falling, the weaker connection between the first region and the first shell can provide a buffering effect for the seal, and the detachment of the connection between the first region and the first shell can dissipate part of the impact kinetic energy received by the seal, thereby reducing the risk of the seal being broken and improving the packaging reliability of the electrochemical device.

[0092] The present application also provides an embodiment of an electric device 2, such as Fig.11 As shown, the electrical device includes the electrochemical device as described above. The function and structure of the electrochemical device can be found in the above embodiments, which will not be described in detail here.

[0093] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An electrochemical device, characterized in that include: a first shell and a second shell; A first separator is located between the first shell and the second shell, the electrochemical device is provided with a first cavity between the first shell and the first separator, and the electrochemical device is provided with a second cavity between the second shell and the first separator; A first electrode assembly and a second electrode assembly, wherein the first electrode assembly is disposed in the first cavity, and the second electrode assembly is disposed in the second cavity; The electrochemical device comprises a first sealing portion, wherein the first sealing portion comprises a first outer edge; the first isolating member comprises a first sealing area located at the first sealing portion, wherein along a width direction of the first sealing area, the first sealing area comprises a first region and a second region, wherein the first region is farther from the first outer edge than the second region; The packaging strength between the first region and the first shell is F1, and the packaging strength between the second region and the first shell is F2, satisfying F2≥2F1 and / or F2-F1≥5N / 8mm.

2. The electrochemical device according to claim 1, characterized in that At least one of the following conditions is met: (1) F1 ≥ 5N / 8mm; (2)F2≥15N / 8mm.

3. The electrochemical device according to claim 1, characterized in that Meet any of the following conditions: (i) the packaging strength between the first region and the second shell is F3, the packaging strength between the second region and the second shell is F4, and F4>F3 is satisfied; (ii) The electrochemical device further includes a second separator located between the first separator and the second shell, the packaging strength between the first region and the second separator is S1, the packaging strength between the second region and the second separator is S2, and S2>S1 is satisfied.

4. The electrochemical device according to claim 3, characterized in that At least one of the following conditions is met: (a) F4 ≥ 2F3; (b) F4-F3 ≥ 5N / 8mm; (c) F3 ≥ 5N / 8mm; (d) F4 ≥ 15N / 8mm; (e) S2 ≥ 2S1; (f) S2-S1 ≥ 5N / 8mm; (g) S1 ≥ 5N / 8mm; (h)S2≥15N / 8mm.

5. The electrochemical device according to claim 1, characterized in that The electrochemical device further comprises a second separator located between the first separator and the second shell, the second separator comprising a second sealing area located at the first sealing portion, the second sealing area comprising a third area and a fourth area, and along a width direction of the second sealing area, the third area is farther from the first outer edge than the fourth area; The packaging strength between the third region and the second shell is F5, and the packaging strength between the fourth region and the second shell is F6, satisfying F6>F5.

6. The electrochemical device according to claim 5, characterized in that At least one of the following conditions is met: (a) F6 ≥ 2F5; (b) F6-F5 ≥ 5N / 8mm; (c) F5 ≥ 5N / 8mm; (d)F6≥15N / 8mm.

7. The electrochemical device according to claim 1, characterized in that Along the width direction of the first sealing area, the width of the first area is D1, and the width of the second area is D2, satisfying: D1 ≥ 0.5 mm, and / or D2 ≥ 0.5 mm.

8. The electrochemical device according to claim 5, characterized in that Along the width direction of the second sealing area, the width of the third area is D3, and the width of the fourth area is D4, satisfying: D3 ≥ 0.5 mm, and / or D4 ≥ 0.5 mm.

9. The electrochemical device according to claim 1, characterized in that At least one of the following conditions is met: (1) The electrochemical device includes a tab module, the tab module includes a first tab and a second tab, one end of the first tab is connected to the first electrode assembly, one end of the second tab is connected to the second electrode assembly, and the other ends of the first tab and the second tab both extend from the first sealing portion; (2) The first electrode assembly and the second electrode assembly are connected in series.

10. An electrical device, characterized in that: The invention comprises an electrochemical device as claimed in any one of claims 1 to 9.

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