Battery and battery pack

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a battery and a battery pack. The battery comprises a first electrode assembly, a second electrode assembly, an isolation layer and a shell, the second electrode assembly and the first electrode assembly are oppositely arranged in the thickness direction of the battery, and the isolation layer is arranged between the first electrode assembly and the second electrode assembly; the side, facing the first electrode assembly, of the isolation layer is provided with a first pressure-sensitive adhesive layer used for being bonded with the first electrode assembly, and the side, facing the second electrode assembly, of the isolation layer is provided with a second pressure-sensitive adhesive layer used for being bonded with the second electrode assembly. The first shell and the isolating layer form a first accommodating cavity for accommodating the first electrode assembly, and the second shell and the isolating layer form a second accommodating cavity for accommodating the second electrode assembly. The battery pack comprises the battery. The battery and the battery pack are favorable for keeping the position consistency of the electrode assemblies arranged in the same shell.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion batteries, and particularly relates to a battery and a battery pack. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density, high output power, high cycle life, etc., and are usually applied in mobile electronic devices such as Bluetooth headsets, mobile phones, laptop computers, tablet computers, cameras, etc., and portable mobile power supplies and other fields. With the rapid progress of electronic product technology, people have put forward higher requirements for the energy density, battery life and fast charging ability of lithium-ion batteries.

[0003] In view of the current higher requirements for the energy density, fast charging ability and battery life of batteries, a single battery cell cannot achieve the output of the desired power. Therefore, usually, multiple battery cells are connected in series, parallel or in a hybrid connection so that the multiple battery cells cooperate with each other to achieve the output of the desired power. However, when multiple battery cells are placed in the same housing for encapsulation, since there are multiple battery cores in the housing at the same time, this results in relatively complex processes such as battery encapsulation and formation, and the series-connected and parallel-connected batteries have relatively high requirements for the position consistency of each battery core. At present, when producing series-connected and parallel-connected batteries, it is impossible to ensure the position consistency of each battery core. Summary of the Utility Model

[0004] The main purpose of the utility model is to propose a battery and a battery pack, aiming to solve the technical problem that the position consistency of each battery core cannot be ensured when producing series-connected and parallel-connected batteries at present.

[0005] To achieve the above object, the utility model proposes a battery, comprising:

[0006] A first electrode assembly;

[0007] A second electrode assembly, the second electrode assembly and the first electrode assembly are arranged opposite to each other along the thickness direction of the battery, and the first electrode assembly and the second electrode assembly are connected in series or in parallel;

[0008] An isolation layer, the isolation layer is arranged between the first electrode assembly and the second electrode assembly for separating the first electrode assembly and the second electrode assembly. A first pressure-sensitive adhesive layer is arranged on the side of the isolation layer facing the first electrode assembly, and the first pressure-sensitive adhesive layer is used for bonding the first electrode assembly. A second pressure-sensitive adhesive layer is arranged on the side of the isolation layer facing the second electrode assembly, and the second pressure-sensitive adhesive layer is used for bonding the second electrode assembly;

[0009] The shell includes a first shell and a second shell, the first shell and the isolation layer form a first accommodating cavity for accommodating the first electrode assembly, and the second shell and the isolation layer form a second accommodating cavity for accommodating the second electrode assembly.

[0010] In some embodiments, the minimum distance L between each edge of the first pressure-sensitive adhesive layer and each edge of the first electrode assembly is 1 Satisfaction: L 1 >4mm, the minimum distance L between each edge of the second pressure-sensitive adhesive layer and each edge of the second electrode assembly 2 Satisfaction: L 2 >4mm.

[0011] In some embodiments, along a direction perpendicular to the direction from the first electrode assembly to the second electrode assembly, the cross-sectional area S of the first pressure-sensitive adhesive layer is 1 and the cross-sectional area S of the first electrode assembly 2 Satisfaction: 0.2<S 1 / S 2 <0.8, the cross-sectional area S of the second pressure-sensitive adhesive layer 3 and the cross-sectional area S of the second electrode assembly 4 Satisfaction: 0.2<S 3 / S 4 <0.8.

[0012] In some embodiments, the isolation layer includes a first heat sealing layer and a second heat sealing layer arranged opposite to each other along the thickness direction of the isolation layer, the first heat sealing layer is arranged on the side of the first pressure-sensitive adhesive layer away from the first electrode assembly, and the second heat sealing layer is arranged on the side of the second pressure-sensitive adhesive layer away from the second electrode assembly.

[0013] In some embodiments, the thickness D of the first heat seal layer 1 Satisfy: 40um≤D 1 ≤80um, the thickness of the second heat seal layer D 2 Satisfy: 40um≤D 2 ≤80um.

[0014] In some embodiments, the first heat-sealing layer and the second heat-sealing layer are one of a polypropylene layer, anhydride-modified polypropylene layer, a polyethylene layer, an ethylene-propylene copolymer layer, a polyvinyl chloride layer, a polystyrene layer, a polyether nitrile layer, a polyurethane layer, a polyamide layer, and a polyester layer.

[0015] In some embodiments, a barrier layer is disposed between the first heat-sealing layer and the second heat-sealing layer.

[0016] In some embodiments, the thickness D of the barrier layer is3 Satisfy: 35um ≤ D 3 ≤ 40um.

[0017] In some embodiments, the barrier layer is one of an Al layer, a Ni layer, a Ti layer, an Ag layer, an Au layer, a Pt layer, an Fe layer, a Co layer, a Cr layer, a W layer, a Mo layer, a Pb layer, an In layer, a Zn layer, a stainless steel layer, a polyethylene naphthalate layer, a polyethylene terephthalate layer, a polybutylene terephthalate layer, a carbon felt layer, a carbon film layer, a carbon black layer, an acetylene black layer, a fullerene layer, a conductive graphite film, and a graphene film.

[0018] In some embodiments, the thickness M of the first pressure-sensitive adhesive layer 1 Satisfy: 10um ≤ M 1 ≤ 25um, and the thickness M of the second pressure-sensitive adhesive layer 2 Satisfy: 10um ≤ M 2 ≤ 25um.

[0019] In some embodiments, the thickness M of the first pressure-sensitive adhesive layer 1 and the thickness D of the first heat-sealing layer 1 Satisfy: 0.2 < M 1 / D 1 < 0.6, and the thickness M of the second pressure-sensitive adhesive layer 2 and the thickness D of the second heat-sealing layer 2 Satisfy: 0.2 < M 2 / D 2 < 0.6.

[0020] Correspondingly, the present utility model further provides a battery pack, including the battery described in any one of the above embodiments.

[0021] Compared with the prior art, the beneficial effects of the present utility model are:

[0022] In the technical solution of the present utility model, an in-series battery is provided. This battery is beneficial to maintaining the positional consistency of two electrode assemblies arranged in the same housing. The battery includes at least two oppositely arranged electrode assemblies. An isolation layer is arranged between the two electrode assemblies to separate the two electrode assemblies and prevent the electrolytes existing in the two electrode assemblies from penetrating each other, ensuring the safety performance of the battery. A pressure-sensitive adhesive layer is arranged on the isolation layer at a position corresponding to the electrode assemblies to bond the electrode assemblies and prevent the electrode assemblies from moving relatively. By arranging the pressure-sensitive adhesive layer, on the one hand, it can effectively fix the two electrode assemblies, improve the positional consistency of the two electrode assemblies, maintain the positional symmetry of the two electrode assemblies, and reduce the manufacturing difficulty of the battery. On the other hand, it can improve the isolation performance of the isolation layer and realize the independent arrangement of the two electrode assemblies in the in-series battery.

[0023] The battery pack using the above battery not only has a high energy density, which is beneficial to improving the fast charging ability and endurance of the battery pack, but also has a simple manufacturing process, and can effectively ensure the position consistency of multiple electrode components in the battery pack. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0025] Figure 1 It is a schematic structural diagram of the battery provided by an embodiment of the present invention after encapsulation;

[0026] Figure 2 It is a schematic diagram of the relative position relationship between the first pressure-sensitive adhesive layer and the first electrode assembly in the battery provided by an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the relative position relationship between the second pressure-sensitive adhesive layer and the second electrode assembly in the battery provided by an embodiment of the present invention.

[0028] Explanation of the reference numerals in the drawings:

[0029] 100 - The first electrode assembly;

[0030] 200 - The second electrode assembly;

[0031] 300 - The isolation layer;

[0032] 310 - The first pressure-sensitive adhesive layer; 320 - The second pressure-sensitive adhesive layer; 330 - The first heat-sealing layer; 340 - The second heat-sealing layer; 350 - The barrier layer;

[0033] 400 - The housing;

[0034] 410 - The first housing; 420 - The second housing;

[0035] 411 - The first accommodating cavity; 421 - The second accommodating cavity.

[0036] The realization of the purpose, functional characteristics and advantages of the present invention will be further described with reference to the embodiments and the drawings. Detailed Embodiments

[0037] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0038] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, then the directional indications are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0039] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, then the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear throughout the text, their meanings include three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0040] Lithium-ion batteries have advantages such as high energy density, high output power, and high cycle life, and are usually used in mobile electronic devices such as Bluetooth headsets, mobile phones, laptops, tablets, cameras, etc. and portable mobile power supplies. With the rapid progress of electronic product technology, people have put forward higher requirements for the energy density, battery life, and fast charging ability of lithium-ion batteries.

[0041] In view of the current higher requirements for the energy density, fast charging ability, and battery life of batteries, a single battery cell cannot achieve the output of the desired power. Therefore, multiple battery cells are usually connected in series, parallel, or in a hybrid connection so that the multiple battery cells cooperate together to achieve the output of the desired power. However, when multiple battery cells are placed in the same housing for encapsulation, since there are multiple battery cores in the housing at the same time, this makes the processes such as battery encapsulation and formation more complex, and the series-parallel connected batteries have higher requirements for the position consistency of each battery core. Currently, when producing series-parallel batteries, it is impossible to ensure the position consistency of each battery core.

[0042] In order to solve the technical problem that it is impossible to ensure the position consistency of each battery cell during the production of series - parallel batteries at present, with reference to Figures 1 to 3 , an embodiment of the present utility model provides a battery, which includes a first electrode assembly 100, a second electrode assembly 200, an isolation layer 300, and a housing 400. The second electrode assembly 200 and the first electrode assembly 100 are arranged opposite to each other along the thickness direction of the battery. The first electrode assembly 100 and the second electrode assembly 200 are connected in series or in parallel. The isolation layer 300 is disposed between the first electrode assembly 100 and the second electrode assembly 200 and is used to separate the first electrode assembly 100 and the second electrode assembly 200. A first pressure - sensitive adhesive layer 310 is provided on the side of the isolation layer 300 facing the first electrode assembly 100, and the first pressure - sensitive adhesive layer 310 is used to bond the first electrode assembly 100. A second pressure - sensitive adhesive layer 320 is provided on the side of the isolation layer 300 facing the second electrode assembly 200, and the second pressure - sensitive adhesive layer 320 is used to bond the second electrode assembly 200. The housing 400 includes a first housing 410 and a second housing 420. The first housing 410 and the isolation layer 300 form a first accommodation cavity 411 for accommodating the first electrode assembly 100, and the second housing 420 and the isolation layer 300 form a second accommodation cavity 421 for accommodating the second electrode assembly 200.

[0043] Specifically, in this embodiment, an in - series battery is provided. This battery is beneficial to maintaining the position consistency of two electrode assemblies arranged in the same housing 400. The battery includes at least two relatively arranged electrode assemblies. An isolation layer 300 is disposed between the two electrode assemblies and is used to separate the two electrode assemblies to prevent the electrolytes existing in the two electrode assemblies from penetrating each other and ensure the safety performance of the battery. A pressure - sensitive adhesive layer is provided on the isolation layer 300 at a position corresponding to the electrode assembly and is used to bond the electrode assembly to prevent the relative movement of the electrode assembly. By providing the pressure - sensitive adhesive layer, on the one hand, it can effectively fix the two electrode assemblies, improve the position consistency of the two electrode assemblies, maintain the position symmetry of the two electrode assemblies, and reduce the manufacturing difficulty of the battery. On the other hand, it can improve the isolation performance of the isolation layer 300 and realize the independent setting of the two electrode assemblies in the in - series battery.

[0044] Furthermore, the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 can be silicone pressure-sensitive adhesive layers with a silicone polymer as the main body, or the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 can also be acrylic and silicone-modified rubber-type pressure-sensitive adhesive layers modified by a silicone polymer. With the above structures, the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 have excellent properties such as chemical resistance, water resistance, oil resistance, solvent resistance, high-temperature resistance, low-temperature resistance, heat degradation resistance, and oxidation degradation resistance, and can bond with a variety of difficult-to-bond materials such as untreated polyolefins (BOPP, PET, PE, etc.), fluoroplastics, polyimides, and polycarbonates, which is beneficial to improving the internal structural stability of the battery and ensuring the safety performance of the battery.

[0045] Furthermore, in some embodiments, the battery may further include more than two electrode assemblies. These electrode assemblies are arranged opposite to each other along the thickness direction of the battery, and these electrode assemblies are connected in series or in parallel. The above-mentioned isolation layer 300 is provided between adjacent two electrode assemblies, and each electrode assembly is bonded to the isolation layer 300 through a pressure-sensitive adhesive layer. By changing the number of electrode assemblies connected in series inside the battery, the output of different desired powers can be achieved to meet the demand for higher-energy batteries.

[0046] In some embodiments, referring to Figures 2 to 3 , the minimum distance L between each edge of the first pressure-sensitive adhesive layer 310 and each edge of the first electrode assembly 100 1 satisfies: L 1 > 4 mm. Exemplarily, for example, the value of L 1 can be 4.5 mm, 5 mm, 5.2 mm, 5.5 mm, 5.6 mm, etc. The minimum distance L between each edge of the second pressure-sensitive adhesive layer 320 and each edge of the second electrode assembly 200 2 satisfies: L 2 > 4 mm. Exemplarily, for example, the value of L 2 can be 4.5 mm, 5 mm, 5.2 mm, 5.5 mm, 5.6 mm, etc.

[0047] Specifically, in this embodiment, the first pressure-sensitive adhesive layer 310 is arranged as close as possible to the center position of the first electrode assembly 100, and the second pressure-sensitive adhesive layer 320 is arranged as close as possible to the center position of the second electrode assembly 200. With such a structure, it is beneficial to fix the electrode assemblies, prevent the electrode assemblies from shifting, affecting the position consistency of the two electrode assemblies, and avoiding waste of materials due to too large an area of the pressure-sensitive adhesive layer, and even affecting the encapsulation of the battery.

[0048] It should be noted that L 1 and L 2can take the same value. Exemplarily, for example, L 1 and L 2 can both take the value of 4.5 mm. Or, L 1 and L 2 can take different values. Exemplarily, for example, L 1 can take the value of 4.5 mm, and L 2 can take the value of 5 mm.

[0049] In some embodiments, the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 may be square structures, such as square structures or rectangular structures. The first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 may also be circular structures, as long as it is beneficial to bond the first electrode assembly 100 and the second electrode assembly 200 to the isolation layer 300.

[0050] In some embodiments, referring to Figures 2 to 3 , along the direction perpendicular to the direction from the first electrode assembly to the second electrode assembly, the cross-sectional area S 1 of the first pressure-sensitive adhesive layer 310 and the cross-sectional area S 2 of the first electrode assembly 100 satisfy: 0.2 < S 1 / S 2 < 0.8. Exemplarily, for example, the value of S 1 / S 2 can be 0.3, 0.4, 0.5, 0.6, 0.7, etc. The cross-sectional area S 3 of the second pressure-sensitive adhesive layer 320 and the cross-sectional area S 4 of the second electrode assembly 200 satisfy: 0.2 < S 3 / S 4 < 0.8. Exemplarily, for example, the value of S 3 / S 4 can be 0.3, 0.4, 0.5, 0.6, 0.7, etc.

[0051] Specifically, in this embodiment, the areas of the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 are limited, and a suitable range of the area ratio of the pressure-sensitive adhesive layer to the electrode assembly is provided, so that the areas of the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 are not too large, thus avoiding waste of materials and even affecting the subsequent battery packaging. At the same time, the areas of the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 are not too small, thus avoiding poor bonding between the electrode assembly and the isolation layer 300. By defining the areas of the first pressure-sensitive adhesive layer 310 and the second pressure-sensitive adhesive layer 320 within the above area range, the electrode assembly can be effectively fixed, and the waste of materials caused by too large an area of the pressure-sensitive adhesive layer can be avoided, and even the battery packaging can be affected.

[0052] It should be noted that S 1 / S 2 and S 3 / S 4 can take the same value. Exemplarily, for example, S 1 / S 2 and S 3 / S 4 can both take the value of 0.5. Or, S 1 / S 2 and S 3 / S 4 can take different values. Exemplarily, for example, the value of S 1 / S 2 can be 0.5, and the value of S 3 / S 4 can be 0.6.

[0053] In some embodiments, referring to Figure 1 , the isolation layer 300 includes a first heat-sealing layer 330 and a second heat-sealing layer 340 that are oppositely arranged along the thickness direction of the isolation layer 300. The first heat-sealing layer 330 is disposed on the side of the first pressure-sensitive adhesive layer 310 away from the first electrode assembly 100, and the second heat-sealing layer 340 is disposed on the side of the second pressure-sensitive adhesive layer 320 away from the second electrode assembly 200.

[0054] Specifically, in this embodiment, the first heat-sealing layer 330 and the second heat-sealing layer 340 have heat-sealing adhesiveness, which is beneficial for sealing and bonding. When the battery is evacuated and packaged, first, the air bags on the first housing 410 and the second housing 420 are punctured, and at the same time, a vacuum is drawn, so that the first housing 410 adheres to the first heat-sealing layer 330, and the second housing 420 adheres to the second heat-sealing layer 340, thereby wrapping the first electrode assembly 100 in the first housing 410 and wrapping the second electrode assembly 200 in the second housing 420, further improving the fixing effect of the first electrode assembly 100 and the second electrode assembly 200 and completing the packaging of the battery.

[0055] In some embodiments, referring to Figure 1 , the thickness D 1 of the first heat-sealing layer 330 satisfies: 40um ≤ D 1 ≤ 80um. Exemplarily, for example, the value of D 1 can be 40um, 50um, 60um, 70um, 80um, etc. The thickness D 2 of the second heat-sealing layer 340 satisfies: 40um ≤ D 2 ≤ 80um. Exemplarily, for example, the value of D 2 can be 40um, 50um, 60um, 70um, 80um, etc.

[0056] Specifically, in this embodiment, a thickness range of the first heat-sealing layer 330 and the second heat-sealing layer 340 is defined. If the thicknesses of the first heat-sealing layer 330 and the second heat-sealing layer 340 are set too thin, for example, if the thicknesses of the first heat-sealing layer 330 and the second heat-sealing layer 340 are set to 30 μm, the bonding performance of the first heat-sealing layer 330 and the second heat-sealing layer 340 will be affected to a certain extent, easily resulting in poor bonding between the first heat-sealing layer 330 and the second heat-sealing layer 340, and making the heat-sealing effect of the battery poor. If the thicknesses of the first heat-sealing layer 330 and the second heat-sealing layer 340 are set too thick, for example, if the thicknesses of the first heat-sealing layer 330 and the second heat-sealing layer 340 are set to 100 μm, it will cause waste of materials, and setting the thicknesses of the first heat-sealing layer 330 and the second heat-sealing layer 340 too thick will increase the overall thickness of the battery, thereby reducing the energy density of the battery.

[0057] It should be noted that D 1 and D 2 can take the same value. For example, D 1 and D 2 can both take a value of 60 μm. Or, D 1 and D 2 can take different values. For example, D 1 can take a value of 50 μm, and D 2 can take a value of 70 μm.

[0058] In some embodiments, the first heat-sealing layer 330 and the second heat-sealing layer 340 are one of a polypropylene layer, an acid anhydride-modified polypropylene layer, a polyethylene layer, an ethylene-propylene copolymer layer, a polyvinyl chloride layer, a polystyrene layer, a polyether nitrile layer, a polyurethane layer, a polyamide layer, and a polyester layer.

[0059] Specifically, in this embodiment, the first heat-sealing layer 330 and the second heat-sealing layer 340 are made of materials with good heat-sealing adhesiveness, strong corrosion resistance, and excellent insulation. The first heat-sealing layer 330 and the second heat-sealing layer 340 can adopt the above single-layer structure. For example, the first heat-sealing layer 330 and the second heat-sealing layer 340 can both be polypropylene layers, or the first heat-sealing layer 330 can be a polypropylene layer and the second heat-sealing layer 340 can be a polyethylene layer. The first heat-sealing layer 330 and the second heat-sealing layer 340 can also adopt a composite layer structure of the above single-layer structure. For example, the first heat-sealing layer 330 and the second heat-sealing layer 340 can both be composite layers of a polypropylene layer and a polyethylene layer, or the first heat-sealing layer 330 can be a composite layer of a polypropylene layer and a polyethylene layer, and the second heat-sealing layer 340 can be a composite layer of a polyamide layer and a polyester layer.

[0060] In some embodiments, referring to Figure 1, a barrier layer 350 is provided between the first heat-sealing layer 330 and the second heat-sealing layer 340. By providing the barrier layer 350, the isolation performance of the isolation layer 300 can be effectively improved. While preventing the intrusion of moisture and oxygen, it can also prevent the electrolytes in the first accommodating cavity 411 and the second accommodating cavity 421 from flowing into each other, thereby ensuring the safety performance of the battery.

[0061] In some embodiments, referring to Figure 1 , the thickness D of the barrier layer 350 3 satisfies: 35um ≤ D 3 ≤ 40um. Exemplarily, the value of D 3 can be 35um, 36um, 37.5um, 38um, 40um, etc.

[0062] Specifically, in this embodiment, a thickness range of the barrier layer 350 is provided. If the thickness of the barrier layer 350 is set too thin, for example, if the thickness of the barrier layer 350 is set to 20um, the isolation performance of the barrier layer 350 will be affected to a certain extent, and it is easy to cause the barrier layer 350 to not play a good isolation role. If the thickness of the barrier layer 350 is set too thick, for example, if the thickness of the barrier layer 350 is set to 50um, it will cause waste of materials, and setting the thickness of the barrier layer 350 too thick will increase the overall thickness of the battery, thereby reducing the energy density of the battery.

[0063] In some embodiments, the barrier layer 350 is one of an Al layer, a Ni layer, a Ti layer, an Ag layer, an Au layer, a Pt layer, an Fe layer, a Co layer, a Cr layer, a W layer, a Mo layer, a Pb layer, an In layer, a Zn layer, a stainless steel layer, a polyethylene naphthalate layer, a polyethylene terephthalate layer, a polybutylene terephthalate layer, a carbon felt layer, a carbon film layer, a carbon black layer, an acetylene black layer, a fullerene layer, a conductive graphite film, a graphene film.

[0064] Specifically, in this embodiment, the barrier layer 350 uses a material with strong anti-pinhole property, good processability, good oxidation resistance, and high waterproofness. The barrier layer 350 can adopt the above single-layer structure. Exemplarily, for example, the barrier layer 350 can be an Al layer, the barrier layer 350 can also be a polyethylene naphthalate layer, the barrier layer 350 can also be a carbon felt layer. The barrier layer 350 can also adopt a composite layer structure of the above single-layer structure. Exemplarily, for example, the barrier layer 350 can be a composite layer of an Al layer and a polyethylene naphthalate layer, the barrier layer 350 can also be a composite layer of an Al layer and a carbon felt layer, and the barrier layer 350 can also be a composite layer of a polyethylene naphthalate layer and a carbon felt layer.

[0065] In some embodiments, referring to Figure 1 , the thickness M of the first pressure-sensitive adhesive layer 3101 Satisfy: 10um ≤ M 1 ≤ 25um, the thickness M of the second pressure - sensitive adhesive layer 320 2 Satisfy: 10um ≤ M 2 ≤ 25um. Exemplarily, for example, M 1 can take values such as 10um, 15um, 20um, 25um, etc., and M 2 can take values such as 10um, 15um, 20um, 25um, etc.

[0066] In some embodiments, referring to Figure 1 , the thickness M of the first pressure - sensitive adhesive layer 310 1 and the thickness D of the first heat - seal layer 330 1 Satisfy: 0.2 < M 1 / D 1 < 0.6, the thickness M of the second pressure - sensitive adhesive layer 320 2 and the thickness D of the second heat - seal layer 340 2 Satisfy: 0.2 < M 2 / D 2 < 0.6. Exemplarily, for example, M 1 / D 1 can take values such as 0.3, 0.35, 0.4, 0.45, 0.5, etc., and M 2 / D 2 can take values such as 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0067] Specifically, in this embodiment, referring to Table 1, for the cross - sectional area S of the first pressure - sensitive adhesive layer 310 1 , the cross - sectional area S of the first electrode assembly 100 2 , the thickness M of the first pressure - sensitive adhesive layer 310 1 and the thickness D of the first heat - seal layer 330 1 , different values are taken. By changing S 1 / S 2 and M 1 / D 1 , several comparative experiments are carried out to verify the influence of changing the design sizes of S 1 / S 2 and M 1 / D 1 on the cycle attenuation rate, rate performance and lithium plating window of the battery.

[0068] Among them, the cyclic decay rate refers to the percentage of the remaining capacity after 800 cycles when the battery is charged in a stepped manner at 3.5C to 4.5V, then the charging rate is changed to 1.5C and charged to the cut-off voltage. The rate performance refers to the ratio of the discharge capacity of the battery at a rate of 3C to the discharge capacity at a rate of 0.2C under normal temperature conditions. The lithium plating window refers to the maximum rate corresponding to no lithium plating on the cell interface after the cell is directly charged to the cut-off voltage under the conditions of 3.5C, 3.2C, 3.0C, 2.8C, 2.6C, 2.4C, and 2.0C.

[0069] S1 S2 M1 D1 S1 / S2 M1 / D1 Cyclic decay rate Rate performance Lithium plating window Example 1 609 3045 16 40 0.2 0.4 88.9％ 97.6％ 3.5C Example 2 1218 3045 16 40 0.4 0.4 87.3％ 97.1％ 3.5C Example 3 1827 3045 16 40 0.6 0.4 83.7％ 94.4％ 3.0C Example 4 2436 3045 16 40 0.8 0.4 82.5％ 93.9％ 2.8C Example 5 1218 3045 12 40 0.4 0.3 87.6％ 98.2％ 3.5C Example 6 1218 3045 20 40 0.4 0.5 84.1％ 93.7％ 3.0C Example 7 1218 3045 24 40 0.4 0.6 83.8％ 93.3％ 3.0C Comparative Example 1 305 3045 16 40 0.1 0.4 79.2％ 89.6％ 2.6C Comparative Example 2 2741 3045 16 40 0.9 0.4 78.4％ 88.8％ 2.4C Comparative Example 3 1218 3045 5 50 0.4 0.1 80.6％ 89.9％ 2.4C Comparative Example 4 1218 3045 35 50 0.4 0.7 79.1％ 87.4％ 2.4C

[0070] Table 1

[0071] As can be seen from Table 1, when the pressure-sensitive adhesive can effectively bond, when 0.2 < S 1 / S 2 < 0.4, the cyclic decay, rate decay, and lithium plating problems can be alleviated, and the smaller the area and thickness of the pressure-sensitive adhesive, the better the performance. When the area of the pressure-sensitive adhesive is too small, it will affect the bonding between the electrode assembly and the heat-sealing layer, affecting the consistency of the series-connected cells. When the area of the pressure-sensitive adhesive is too large and the thickness is too thick, it will affect the wetting degree of the electrolyte with the positive and negative electrode materials, increase the contact resistance, slow down the ion migration rate, thereby affecting the cyclic decay rate, rate performance, and causing lithium plating problems. In addition, it will also affect the heat dissipation of the battery, causing the local temperature of the battery to rise too fast, with the risk of thermal runaway caused by short circuit.

[0072] Correspondingly, another embodiment of the present invention further provides a battery pack, which includes the battery in any of the above embodiments.

[0073] Specifically, in this embodiment, the battery pack applying the above battery not only has a high energy density, which is beneficial to improving the fast charging ability and endurance of the battery pack, but also has a simple manufacturing process and can effectively ensure the position consistency of multiple electrode assemblies in the battery pack. Thanks to the improvement of the above battery, the battery pack in this embodiment has the same technical effects as the above battery, which will not be elaborated here.

[0074] It should be noted that other contents of the battery and battery pack disclosed in the present invention can be referred to the prior art, which will not be elaborated here.

[0075] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A battery, characterized in that: include: a first electrode assembly; a second electrode assembly, wherein the second electrode assembly and the first electrode assembly are arranged opposite to each other along the thickness direction of the battery, and the first electrode assembly and the second electrode assembly are connected in series or in parallel; an isolation layer, the isolation layer being arranged between the first electrode assembly and the second electrode assembly and being used to separate the first electrode assembly and the second electrode assembly, a first pressure-sensitive adhesive layer being arranged on a side of the isolation layer facing the first electrode assembly and being used to bond the first electrode assembly, and a second pressure-sensitive adhesive layer being arranged on a side of the isolation layer facing the second electrode assembly and being used to bond the second electrode assembly; The shell includes a first shell and a second shell, the first shell and the isolation layer form a first accommodating cavity for accommodating the first electrode assembly, and the second shell and the isolation layer form a second accommodating cavity for accommodating the second electrode assembly.

2. The battery according to claim 1, characterized in that The minimum distance L1 between each edge of the first pressure-sensitive adhesive layer and each edge of the first electrode assembly satisfies: L1>4mm, and the minimum distance L2 between each edge of the second pressure-sensitive adhesive layer and each edge of the second electrode assembly satisfies: L2>4mm.

3. The battery according to claim 1, characterized in that Along the direction perpendicular to the direction from the first electrode assembly to the second electrode assembly, the cross-sectional area S1 of the first pressure-sensitive adhesive layer and the cross-sectional area S2 of the first electrode assembly satisfy: 0.2<S1 / S2<0.8, and the cross-sectional area S3 of the second pressure-sensitive adhesive layer and the cross-sectional area S4 of the second electrode assembly satisfy: 0.2<S3 / S4<0.

8.

4. The battery according to claim 1, characterized in that The isolation layer includes a first heat sealing layer and a second heat sealing layer which are arranged opposite to each other along the thickness direction of the isolation layer. The first heat sealing layer is arranged on a side of the first pressure-sensitive adhesive layer away from the first electrode assembly, and the second heat sealing layer is arranged on a side of the second pressure-sensitive adhesive layer away from the second electrode assembly.

5. The battery according to claim 4, characterized in that The thickness D1 of the first heat-sealing layer satisfies: 40um≤D1≤80um, and the thickness D2 of the second heat-sealing layer satisfies: 40um≤D2≤80um.

6. The battery according to claim 4, characterized in that The first heat-sealing layer and the second heat-sealing layer are one of a polypropylene layer, anhydride-modified polypropylene layer, a polyethylene layer, an ethylene-propylene copolymer layer, a polyvinyl chloride layer, a polystyrene layer, a polyether nitrile layer, a polyurethane layer, a polyamide layer, and a polyester layer.

7. The battery according to claim 4, characterized in that A barrier layer is arranged between the first heat-sealing layer and the second heat-sealing layer.

8. The battery according to claim 7, characterized in that The thickness D3 of the barrier layer satisfies: 35um≤D3≤40um.

9. The battery according to claim 7, characterized in that The barrier layer is one of an Al layer, a Ni layer, a Ti layer, an Ag layer, an Au layer, a Pt layer, a Fe layer, a Co layer, a Cr layer, a W layer, a Mo layer, a Pb layer, an In layer, a Zn layer, a stainless steel layer, a polyethylene naphthalate layer, a polyethylene terephthalate layer, a polybutylene terephthalate layer, a carbon felt layer, a carbon film layer, a carbon black layer, an acetylene black layer, a fullerene layer, a conductive graphite film, and a graphene film.

10. The battery according to claim 5, characterized in that The thickness M1 of the first pressure-sensitive adhesive layer satisfies: 10um≤M1≤25um, and the thickness M2 of the second pressure-sensitive adhesive layer satisfies: 10um≤M2≤25um.

11. The battery according to claim 10, characterized in that The thickness M1 of the first pressure-sensitive adhesive layer and the thickness D1 of the first heat-sealing layer satisfy: 0.2<M1 / D1<0.6, and the thickness M2 of the second pressure-sensitive adhesive layer and the thickness D2 of the second heat-sealing layer satisfy: 0.2<M2 / D2<0.

6.

12. A battery pack, characterized in that: A battery comprising any one of claims 1 to 11.

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