Electrode assembly

Abstract

The utility model relates to the technical field of battery manufacturing, and discloses an electrode assembly which comprises a first pole piece, a second pole piece, a first diaphragm, a second diaphragm and a supporting assembly, when the electrode assembly works, the battery cell body expands, and the first supporting layer attached to the inner wall surface of the accommodating space supports the battery cell body, so that expansion and displacement of the battery cell body towards the accommodating space are inhibited, interface contact is improved, and lithium precipitation is improved; the second supporting layer is arranged in the first supporting layer, and the elastic modulus of the second supporting layer is smaller than that of the first supporting layer, so that the first supporting layer can contract towards the interior of the first supporting layer under a relatively high pressure to adapt to relatively high expansion of the battery cell body, and interface contact is guaranteed; therefore, the normal use of the electrode assembly at the end of the battery cell circulation is ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing technology, and in particular to an electrode assembly. Background Technology

[0002] Electrode assemblies can be classified into stacked electrode assemblies and wound electrode assemblies according to their internal molding process. Wound electrode assemblies have a longer development history and more mature molding process. Due to their lower production cost and higher yield rate, they are still widely used.

[0003] During the charging and discharging process, the electrode plates in the electrode assembly may deform, wrinkle, or even break due to expansion and contraction, which seriously affects the cycle life and safety performance of the battery.

[0004] For wound electrode assemblies, a common solution is to incorporate a rigid support structure inside the assembly to address the deformation caused by electrode expansion during charging and discharging. This mitigates electrode wrinkling due to expansion and alleviates lithium plating during cycling. However, towards the end of the cycle, the overall expansion of the electrode assembly is significant. The interaction between the internal support and the expanded assembly can easily damage the structure, causing the assembly to fail before its intended lifespan. Utility Model Content

[0005] The purpose of this invention is to provide an electrode assembly that solves the problem in the prior art where setting a rigid support structure inside the battery cell easily leads to the premature scrapping of the battery cell before its set lifespan.

[0006] To achieve the above objectives, this utility model provides an electrode assembly comprising a first electrode, a second electrode, a first diaphragm, a second diaphragm, and a support assembly;

[0007] The first diaphragm, the first electrode, the second diaphragm, and the second electrode are stacked and wound along the winding direction to form the cell body; the middle part of the cell body has a receiving space formed by the winding and enclosure;

[0008] The support component is disposed in the receiving space, and the outer peripheral surface of the support component is in contact with the inner wall surface of the receiving space;

[0009] The support component includes a first support layer and a second support layer, wherein the first support layer covers and is disposed on the outer periphery of the second support layer;

[0010] The elastic modulus of the first support layer is greater than that of the second support layer; the first support layer is used to support the battery cell body.

[0011] In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0012] Furthermore, the support component includes at least two first support layers and at least two second support layers; the first support layers and the second support layers are alternately arranged; wherein one second support layer is located in the innermost layer of the support component and one first support layer is located in the outermost layer of the support component.

[0013] Furthermore, under a preset pressure of 0.8 MPa, the compressibility of the first support layer is 5%-15%, and the compressibility of the second support layer is 50%-90%.

[0014] Furthermore, both the first support layer and the second support layer are foamed structures; the foaming rate of the first support layer is 0-10%, and the foaming rate of the second support layer is 15-35%.

[0015] Furthermore, the bubble diameter in the foamed structure of the first support layer is 30–100 μm, and the bubble diameter in the foamed structure of the second support layer is 120–200 μm.

[0016] Furthermore, in the height direction of the electrode assembly, at least one end face of the second support layer is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte;

[0017] and / or;

[0018] In the height direction of the electrode assembly, at least one end face of the first support layer is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte.

[0019] Further, along the height direction of the electrode assembly, the region of the through hole and / or blind hole has a first height S1; the region in the second support layer where no through hole and / or blind hole is formed is defined as a closed-hole region; along the height direction of the electrode assembly, the closed-hole region has a second height S2; wherein, 0.5*S1≤S2≤5*S1;

[0020] and / or;

[0021] Along the height direction of the electrode assembly, the region of through holes and / or blind holes on the first support layer has a first height H1; the region in the first support layer where no through holes and / or blind holes are formed is defined as a closed-hole region; along the height direction of the electrode assembly, the closed-hole region has a second height H2; wherein, 0.5*H1≤H2≤5*H1.

[0022] Furthermore, along the height direction of the electrode assembly, the through-hole and / or blind-hole regions and closed-hole regions on the second support layer do not overlap, and the sum of S1 and S2 is the height of the second support layer. That is, along the height direction of the electrode assembly, the through-hole and / or blind-hole regions and closed-hole regions on the second support layer are in contact with each other, but do not overlap.

[0023] Furthermore, along the height direction of the electrode assembly, the through-hole and / or blind-hole regions and closed-hole regions on the first support layer do not overlap, and the sum of H1 and H2 is the height of the first support layer. That is, along the height direction of the electrode assembly, the through-hole and / or blind-hole regions and closed-hole regions on the first support layer are in contact with each other, but do not overlap.

[0024] Furthermore, in the height direction of the electrode assembly, at least one end face of the second support layer is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte; and the first support layer may not have through holes and / or blind holes.

[0025] Furthermore, along the thickness direction of the electrode assembly, the sum of the thicknesses of all the first support layers within the support assembly is d1, and the sum of the thicknesses of all the second support layers is d2.

[0026] Where d1≤d2≤8*d1.

[0027] Furthermore, an adhesive layer is also provided on the outer periphery of the first support layer;

[0028] The first support layer is bonded and fixed to the inner wall of the accommodating space by the adhesive layer.

[0029] Furthermore, the material of the coating layer is polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, acrylic copolymer, polyacrylonitrile, or aramid.

[0030] Furthermore, the first support layer is made of polymethyl methacrylate, polyethylene terephthalate, or polytetrafluoroethylene; the second support layer is made of polyethylene, polypropylene, polyurethane, or silicone rubber.

[0031] Compared with the prior art, the battery with electrode assembly provided by this utility model has the following advantages:

[0032] This utility model provides an electrode assembly comprising a first electrode, a second electrode, a first diaphragm, a second diaphragm, and a support assembly. During operation, the battery cell expands, and the pressure from this expansion towards the receiving space acts on a first support layer that is in contact with the inner wall of the receiving space. The first support layer has a high elastic modulus and provides support to the battery cell, thereby suppressing the expansion and displacement of the battery cell towards the receiving space, improving the interfacial contact between the first and second electrodes, and consequently improving lithium plating. Furthermore, when the electrode assembly reaches the end of its cycle, the battery cell expands significantly. Because the first support layer includes a second support layer with a lower elastic modulus, the first support layer can contract inward under greater pressure to accommodate the larger expansion of the battery cell, ensuring interfacial contact with the battery cell and thus guaranteeing normal use of the electrode assembly at the end of its cycle, preventing the electrode assembly from failing before its designed lifespan.

[0033] This utility model also provides a battery, which includes a housing and the aforementioned electrode assembly; by placing the electrode assembly in the housing, a battery is assembled to facilitate subsequent use. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view of an electrode assembly according to an embodiment of the present utility model;

[0035] Figure 2 This is a cross-sectional view of a battery according to an embodiment of the present invention.

[0036] In the figure, 1000 is the battery; 100 is the electrode assembly; 200 is the housing; 1 is the cell body; 10 is the housing space; 11 is the first electrode; 12 is the second electrode; 13 is the first separator; 14 is the second separator; 2 is the support assembly; 21 is the first support layer; and 22 is the second support layer. Detailed Implementation

[0037] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0038] In the description of this utility model, it should be understood that the terms "first electrode," "second electrode," "first separator," and "second separator" used in this utility model all belong to the prior art in the field of lithium battery technology, and their specific structures and "winding along the winding direction" should also belong to the prior art. In this utility model, the term "volume" refers to the volume of the second support layer and the first support layer when not subjected to external force; the term "thickness" refers to the thickness of the support assembly when not subjected to external force.

[0039] like Figure 1 As shown, an electrode assembly 100 according to an embodiment of the present invention includes a first electrode 11, a second electrode 12, a first diaphragm 13, a second diaphragm 14, and a support assembly 2.

[0040] The first diaphragm 13, the first electrode 11, the second diaphragm 14, and the second electrode 12 are stacked and wound along the winding direction to form the cell body 1; the middle part of the cell body 1 has a receiving space 10 formed by winding and enclosing.

[0041] The support component 2 is disposed in the receiving space 10, and the outer peripheral surface of the support component 2 is in contact with the inner wall surface of the receiving space 10.

[0042] The support component 2 includes a first support layer 21 and a second support layer 22; the first support layer 21 covers and is disposed on the outer periphery of the second support layer 22.

[0043] The elastic modulus of the first support layer 21 is greater than that of the second support layer 22; the first support layer is used to support the battery cell body;

[0044] Among them, one of the first electrode 11 and the second electrode 12 is a positive electrode, and the other is a negative electrode.

[0045] Based on the above technical solution, during the operation of the electrode assembly 100, the cell body 1 expands. The pressure caused by the expansion of the cell body toward the receiving space 10 will act on the first support layer 21 that is in contact with the inner wall of the receiving space 10. The first support layer 21 has a large elastic modulus and can provide support for the cell body 1. Thus, the first support layer 21 can suppress the displacement of the cell body 1 toward the receiving space 10, thereby improving the interface contact between the first electrode 11 and the second electrode 12, and thus improving lithium plating. When the electrode assembly 100 reaches the end of the cycle, the cell body 1 will expand significantly. Since the first support layer 21 has a second support layer 22 with a smaller elastic modulus inside, the first support layer 21 can contract inward under greater pressure to adapt to the large expansion of the cell body 1, thereby ensuring interface contact with the cell body 1, and thus ensuring normal use of the electrode assembly 100 when it reaches the end of the cycle, thereby preventing the electrode assembly 100 from being scrapped before its designed service life.

[0046] Preferably, the support component 2 includes at least two first support layers 21 and at least two second support layers 22; the first support layers 21 and the second support layers 22 are alternately arranged from the outside to the inside; such that one second support layer 22 is located in the innermost layer of the support component 2, and one first support layer 21 is located in the outermost layer of the support component 2; thereby forming a multi-layer structure, and by placing one of the first support layers 21 in the inner layer, the thermal shrinkage phenomenon of the second support layer 22 located outside the first support layer 21 in the hot baking stage process is suppressed, so as to ensure the yield of the support component 2.

[0047] Preferably, such as Figure 1 As shown, in this embodiment, the support component 2 includes two first support layers 21 and two second support layers 22, and the first support layers 21 and the second support layers 22 are alternately arranged from the outside to the inside and are sequentially attached; the second support layer 22 is suppressed by the first support layer 21 arranged on the inside to suppress the thermal shrinkage phenomenon of the second support layer 22 in the baking process of the electrode component 100.

[0048] Preferably, such as Figure 1 As shown, in this embodiment, the first support layer 21 and the second support layer 22, which are alternately arranged from the outside to the inside, are coaxially arranged so that when the support assembly 2 is subjected to pressure caused by the expansion of the first electrode 11 and the second electrode 12 toward the receiving space 10, the pressure can be transmitted radially evenly, and each layer is subjected to force evenly, so as to avoid damage to the first support layer 21 and the second support layer 22 due to uneven local force.

[0049] Furthermore, under a preset pressure of 0.8 MPa, in order for the first support layer 21 to provide sufficient reaction force to the cell body 1, the compressibility of the first support layer 21 is 5%-15%, to prevent the first support layer 21 from being compressed under the pressure of the normal inward expansion of the cell body 1; the compressibility of the second support layer 22 is 50%-90%, so that when the electrode assembly 100 reaches the end of the cycle and the cell body 1 expands significantly and compresses the first support layer 21, the first support layer 21 can contract inward, thereby adapting to the large expansion pressure brought by the cell body 1 and ensuring interface contact.

[0050] Preferably, under a preset pressure of 0.8 MPa, the compressibility of the first support layer 21 is 5%-10% to ensure that the first support layer 21 can provide sufficient outward reaction force, thereby effectively limiting the inward displacement of the first electrode 11 and the second electrode 12; the compressibility of the second support layer 22 is 70%-90% to ensure that the first support layer 21 can further contract inward when subjected to greater pressure. In this embodiment, the compressibility of the first support layer 21 is set to 10%, and the compressibility of the second support layer 22 is set to 80%.

[0051] Furthermore, both the first support layer 21 and the second support layer 22 are foamed structures; the foaming rate of the first support layer 21 is 0-10%, and the foaming rate of the second support layer 22 is 15-35%. The difference in compressibility between the first support layer 21 and the second support layer 22 is achieved through different foaming rates.

[0052] Furthermore, in order to specifically realize the design and processing of the foam structure, the foam diameter in the first support layer 21 is 30-100μm, and the foam diameter in the second support layer 22 is 120-200μm.

[0053] Preferably, the bubble wall thickness of the first support layer 21 is 100–500 μm, and the bubble wall thickness of the second support layer 22 is 10–100 μm. By defining different bubble wall thicknesses, the production and processing of the first support layer 21 and the second support layer 22 with different specifications and performance can be achieved.

[0054] Furthermore, in the height direction of the electrode assembly 100 (the height direction of the electrode assembly 100 is the direction in which the tabs of the electrode assembly 100 extend from the battery cell body 1), at least one end face of the second support layer 22 is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte.

[0055] and / or;

[0056] In the height direction of the electrode assembly 100, at least one end face of the first support layer 21 is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte.

[0057] It is understood that the height direction of the electrode assembly 100 refers to... Figure 1The normal direction of the cross-section of the electrode assembly shown; the through-hole and / or blind-hole structures of the second support layer 22 and / or the first support layer 21 can absorb the electrolyte after the electrolyte is injected into the electrode assembly 100, serving as a temporary storage space for the electrolyte in the electrode assembly 100; when the cell body 1 expands, the second support layer 22 and / or the first support layer 21 will be subjected to a certain pressure, under which the electrolyte in the through-hole and / or blind-hole structures will be discharged, thereby ensuring the abundance of electrolyte in the electrode assembly 100 and thus improving the cycle life of the electrode assembly 100.

[0058] Preferably, in the height direction of the electrode assembly 100, the second support layer 22 and / or the first support layer 21 have through holes and / or blind holes on the end face of the electrode assembly 100 where the tab is provided.

[0059] Understandably, in the height direction of the electrode assembly 100, after injection, the electrolyte typically flows towards the bottom of the electrode assembly 100 under the influence of gravity, while the wetting effect on the upper part of the electrode assembly 100 is not as good as that at the bottom. Simultaneously, during circulation, the electrolyte in the upper part of the electrode assembly 100 is usually consumed more easily.

[0060] When using the electrode assembly 100, the end face of the electrode assembly 100 with the tab is usually facing upward. Therefore, this application provides through holes and / or blind holes on the end face of the second support layer 22 and / or the first support layer 21 facing the electrode assembly 100 where the tab is provided. This allows the second support layer 22 and / or the first support layer 21 to discharge electrolyte when under pressure, which is more convenient for wetting the upper part of the electrode assembly 100.

[0061] Furthermore, to ensure that the second support layer 22 has sufficient electrolyte storage space and to maintain the structural integrity of the second support layer 22; along the height direction of the electrode assembly 100, the region of the through holes and / or blind holes on the second support layer 22 has a first height S1; the region in the second support layer 22 where no through holes and / or blind holes are formed is defined as a closed-hole region; along the height direction of the electrode assembly 100, the closed-hole region has a second height S2; wherein, 0.5*S1≤S2≤5*S1;

[0062] and / or;

[0063] Along the height direction of the electrode assembly 100, the regions of through holes and / or blind holes on the first support layer 21 have a first height H1; the regions in the first support layer 21 where no through holes and / or blind holes are formed are defined as closed-hole regions; along the height direction of the electrode assembly 100, the closed-hole regions have a second height H2; wherein, 0.5*H1≤H2≤5*H1.

[0064] Preferably, 2*S1≤S2≤5*S1, and the height of the closed-hole region is preferably higher. If the height of the through-hole is too high, it will absorb too much electrolyte, resulting in a significant increase in battery weight and a substantial decrease in battery energy density.

[0065] Preferably, 2*H1≤H2≤5*H1, and the height of the closed-cell region is preferably higher. If the height of the through-cell is too high, it will absorb too much electrolyte, resulting in a significant increase in battery weight and a substantial decrease in battery energy density.

[0066] Furthermore, along the height direction of the electrode assembly 100, the through-hole and / or blind-hole regions and closed-hole regions on the second support layer 22 do not overlap, and the sum of S1 and S2 is the height of the second support layer. That is, along the height direction of the electrode assembly 100, the through-hole and / or blind-hole regions and closed-hole regions on the second support layer 22 are in contact with each other, but do not overlap.

[0067] Furthermore, along the height direction of the electrode assembly 100, the through-hole and / or blind-hole regions and the closed-hole regions on the first support layer 21 do not overlap, and the sum of H1 and H2 is the height of the first support layer 21. That is, along the height direction of the electrode assembly 100, the through-hole and / or blind-hole regions and the closed-hole regions on the first support layer 21 are in contact with each other, but do not overlap.

[0068] Furthermore, in the height direction of the electrode assembly 100, at least one end face of the second support layer 22 is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte; and the first support layer 21 may not have through holes and / or blind holes.

[0069] Furthermore, along the thickness direction of the electrode assembly 100 (i.e. Figure 1In the vertical direction of the structure, the sum of the thicknesses of all the first support layers 21 within the support assembly 2 is d1, and the sum of the thicknesses of all the second support layers 22 is d2; where d1≤d2≤8*d1. The sum of the thicknesses of all the first support layers 21 within the entire support assembly 2 needs to be limited to a suitable range. If the sum of the thicknesses of all the first support layers 21 is greater than the sum of the thicknesses of all the second support layers 22, then the thickness of the first support layers 21 within the support assembly 2 is relatively large. Since the cell body 1 will undergo significant expansion when the electrode assembly 100 reaches the end of the cycle, if the first support layer 21 is relatively thick and the second support layer 22 is relatively small, it will be difficult for the first support layer 21 to compress inward, thereby causing the first support layer 21 to be unable to adapt to the significant expansion at the end of the cell cycle and failing to guarantee the normal use of the electrode assembly 100. If the sum of the thicknesses of all the first support layers 21 is still less than 8 times the sum of the thicknesses of all the second support layers 22, it indicates that the thickness of the first support layer 21 in the support assembly 2 is too small. It cannot provide sufficient reaction force to the battery cell body 1 when the battery cell body 1 expands inward, which can easily lead to the battery cell body 1 not receiving effective support. Furthermore, the second support layer 22 has a higher compressibility, which can easily cause the first support layer 21 to separate from the battery cell body 1, resulting in problems such as wrinkling.

[0070] Preferably, to balance the effective support and inward contraction of the first support layer 21 to the cell body 1, it is further preferred that 4d1≤d2≤8*d1. In this embodiment, 4d1=d2.

[0071] Preferably, such as Figure 1 As shown, in order to ensure the energy density of the battery and prevent the support component 2 from occupying too much space while playing a role in improving lithium plating, the thickness of the cell body 1 is defined as D1, and the thickness of the support component 2 is defined as D2; wherein, 3%*D1≤D2≤12%*D1.

[0072] Preferably, such as Figure 1 As shown, to balance the improving effect of the support component 2 and the energy density of the battery, in this embodiment, 7%*D1≤D2≤12%*D1 is used to ensure that the support component 2 has sufficient thickness to improve lithium plating. In this embodiment, 7%*D1=D2.

[0073] Preferably, the first support layer 21 is made of polymethyl methacrylate, polyethylene terephthalate, or polytetrafluoroethylene; polymethyl methacrylate, polyethylene terephthalate, and polytetrafluoroethylene have high mechanical strength and stiffness, which can provide sufficient outward reaction force when the battery cell body 1 expands inward. In this embodiment, the first support layer 21 is made of polymethyl methacrylate.

[0074] The second support layer 22 is made of polyethylene, polypropylene, polyurethane, or silicone rubber. Polyethylene, polypropylene, polyurethane, and silicone rubber all have high flexibility and compressibility, allowing the first support layer 21 to continue contracting inward to accommodate greater expansion pressure. In this embodiment, the second support layer 22 is made of silicone rubber.

[0075] Furthermore, an adhesive layer (not shown in the figure) is also provided on the outer periphery of the first support layer 21; the first support layer 21 is bonded and fixed to the inner wall of the receiving space 10 through the adhesive layer; thereby enabling the first electrode 11 and the second electrode 12 constituting the battery cell body 1 to remain relatively fixed during expansion and contraction, without significant displacement or sliding that could damage the battery cell body 1. The thickness of the adhesive layer is 0.5 to 3 μm to ensure sufficient adhesion and fixation.

[0076] Preferably, the thickness of the adhesive coating layer is further preferably 0.5–1 μm to avoid the adhesive coating layer being too thick, which would affect the heat dissipation of the first electrode 11 and the second electrode 12, and easily lead to the expansion pressure of the first electrode 11 and the second electrode 12 not being fully transmitted to the first support layer 21. In this embodiment, the adhesive coating layer melts during the hot pressing process, and then adheres and fixes itself to the diaphragm located on the innermost side of the cell body 1, thereby achieving positioning and fixation. In this embodiment, the thickness of the adhesive coating layer is set to 1 μm.

[0077] Furthermore, the adhesive layer is made of polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, acrylic copolymer, polyacrylonitrile, or aramid to obtain good adhesive properties. In this embodiment, the adhesive layer is made of polyvinylidene fluoride.

[0078] Preferably, the first support layer 21 and the second support layer 22 are integrally formed, and the second support layer and the first support layer are integrally connected without an adhesive layer. By preparing adhesive solutions of different compositions, the adhesive solutions are sequentially applied to the substrate by coating, irradiated under ultraviolet light with a wavelength of 200-280 nm for 30-60 minutes, and then baked at 100-150°C for 3-15 minutes. After processes such as slitting and cutting, the integral second support layer and the first support layer are obtained.

[0079] like Figure 2 As shown, the present invention also provides a battery 1000, which includes a housing 200 and the aforementioned electrode assembly 100; the electrode assembly 100 is placed in the housing 200.

[0080] Based on the above technical solution, the battery 1000 is assembled by placing the electrode assembly 100 in the housing 200, which facilitates subsequent use.

[0081] Preferably, in this embodiment, the two electrode assemblies 100 are placed in the housing 200 to increase the total energy capacity of the battery 1000 and effectively utilize the internal space of the housing 200 to meet the requirements of high energy density.

[0082] The working process of this utility model is as follows: when the electrode assembly 100 is working, the battery cell body 1 expands, and the first support layer 21, which is in contact with the inner wall of the accommodating space, gives the battery cell body 1 an outward reaction force to limit the displacement of the battery cell body 1 toward the accommodating space 10.

[0083] When the electrode assembly 100 reaches the end of the cycle, the cell body 1 undergoes a large expansion. Since the first support layer 21 is internally a second support layer 22, the first support layer 21 can contract inward under greater pressure to accommodate the large expansion of the cell body 1, thereby ensuring interface contact with the cell body 1 and thus ensuring normal use of the electrode assembly 100 when it reaches the end of the cell cycle.

[0084] In summary, this utility model embodiment provides an electrode assembly 100, comprising a first electrode 11, a second electrode 12, a first diaphragm 13, a second diaphragm 14, and a support assembly 2. During the operation of the electrode assembly 100, the battery cell body 1 expands. The pressure generated by the expansion of the battery cell body 1 toward the receiving space 10 acts on the first support layer 21, which is in contact with the inner wall of the receiving space 10. The first support layer 21 has a large elastic modulus and can provide support to the battery cell body 1. Therefore, the first support layer 21 can suppress the expansion and displacement of the battery cell body 1 toward the receiving space 10. Improving the interface contact between the first electrode 11 and the second electrode 12 improves lithium plating. When the electrode assembly 100 reaches the end of the cell cycle, the cell body 1 will expand significantly. Since the first support layer 21 has a second support layer 22 with a smaller elastic modulus inside, the first support layer 21 can contract inward under greater pressure to adapt to the large expansion of the cell body 1, thereby ensuring interface contact with the cell body 1 and ensuring normal use of the electrode assembly 100 when it reaches the end of the cell cycle, thus preventing the electrode assembly 100 from being scrapped before its designed service life.

[0085] This utility model also provides a battery 1000, which includes a housing 200 and the aforementioned electrode assembly 100; by placing the electrode assembly 100 in the housing 200, the battery 1000 is assembled and formed, which facilitates subsequent use.

[0086] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. An electrode assembly, characterized in that, It includes a first electrode, a second electrode, a first diaphragm, a second diaphragm, and a support assembly; The first diaphragm, the first electrode, the second diaphragm, and the second electrode are stacked and wound along the winding direction to form the cell body; the middle part of the cell body has a receiving space formed by the winding and enclosure; The support component is disposed in the receiving space, and the outer peripheral surface of the support component is in contact with the inner wall surface of the receiving space; The support component includes a first support layer and a second support layer, wherein the first support layer covers and is disposed on the outer periphery of the second support layer; The elastic modulus of the first support layer is greater than that of the second support layer; the first support layer is used to support the battery cell body. In this configuration, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

2. The electrode assembly as described in claim 1, characterized in that, The support assembly includes at least two first support layers and at least two second support layers; the first support layers and the second support layers are alternately arranged; wherein one second support layer is located in the innermost layer of the support assembly and one first support layer is located in the outermost layer of the support assembly.

3. The electrode assembly as described in claim 1, characterized in that, Under a preset pressure of 0.8 MPa, the compressibility of the first support layer is 5%-15%, and the compressibility of the second support layer is 50%-90%.

4. The electrode assembly as claimed in claim 1, characterized in that, Both the first support layer and the second support layer are foamed structures; the foaming rate of the first support layer is 0-10%, and the foaming rate of the second support layer is 15-35%. And / or; the bubble diameter in the foam structure of the first support layer is 30-100 μm, and the bubble diameter in the foam structure of the second support layer is 120-200 μm.

5. The electrode assembly as claimed in claim 1, characterized in that, In the height direction of the electrode assembly, at least one end face of the second support layer is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte; and / or; In the height direction of the electrode assembly, at least one end face of the first support layer is formed with through holes and / or blind holes; the through holes and / or blind holes are used to absorb electrolyte.

6. The electrode assembly as claimed in claim 5, characterized in that, Along the height direction of the electrode assembly, the region of through holes and / or blind holes on the second support layer has a first height S1; the region in the second support layer where no through holes and / or blind holes are formed is defined as a closed-hole region; along the height direction of the electrode assembly, the closed-hole region has a second height S2; wherein, 0.5*S1≤S2≤5*S1; and / or; Along the height direction of the electrode assembly, the region of through holes and / or blind holes on the first support layer has a first height H1; the region in the first support layer where no through holes and / or blind holes are formed is defined as a closed-hole region; along the height direction of the electrode assembly, the closed-hole region has a second height H2; wherein, 0.5*H1≤H2≤5*H1.

7. The electrode assembly as claimed in claim 1, characterized in that, Along the thickness direction of the electrode assembly, the sum of the thicknesses of all the first support layers in the support assembly is d1, and the sum of the thicknesses of all the second support layers is d2; Where d1≤d2≤8*d1.

8. The electrode assembly as claimed in claim 1, characterized in that, The outer periphery of the first support layer is also provided with an adhesive layer; The first support layer is bonded and fixed to the inner wall of the accommodating space by the adhesive layer.

9. The electrode assembly as claimed in claim 8, characterized in that, The coating layer is made of polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, acrylic copolymer, polyacrylonitrile, or aramid.

10. The electrode assembly as claimed in claim 1, characterized in that, The first support layer is made of polymethyl methacrylate, polyethylene terephthalate, or polytetrafluoroethylene; the second support layer is made of polyethylene, polypropylene, polyurethane, or silicone rubber.

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