Composite foil and battery

Abstract

The utility model discloses a kind of composite foil, including foil layer and substrate layer, the substrate layer is macromolecular layer;The substrate layer has connecting surface, and the connecting surface of the substrate layer is equipped with the foil layer;The substrate layer includes filler hole, and the filler hole has interval between the connecting surface, and the filler hole is filled with fire extinguishing material.The utility model improves the safety performance when battery thermal runaway.The utility model further discloses a kind of battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a composite foil material and a battery. Background Technology

[0002] As the primary power source for new energy vehicles, the demand for lithium batteries is increasing daily. With rising demands for longer driving ranges and the occurrence of battery fires, higher requirements are being placed on their safety performance. Utility Model Content

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a composite foil material and battery to improve the safety performance of the battery during thermal runaway.

[0004] The objective of this utility model is achieved through the following technical solution:

[0005] This utility model provides a composite foil material, comprising a foil layer and a substrate layer, wherein the substrate layer is a polymer layer; the substrate layer has a connecting surface, and the foil layer is disposed on the connecting surface of the substrate layer; the substrate layer includes filler holes, and there is a gap between the filler holes and the connecting surface, wherein the filler holes are filled with fire extinguishing material.

[0006] In one embodiment, the composite foil has a thickness direction, and the connecting surface is a surface of the substrate layer perpendicular to the thickness direction; the substrate layer has at least one side surface parallel to the thickness direction, and the filler hole penetrates at least one side surface.

[0007] In one embodiment, the substrate layer includes at least one of the filler holes, the at least one of the filler holes being filled with fire extinguishing material, the substrate layer having at least a pair of opposing side surfaces, the filler hole penetrating the pair of opposing side surfaces of the substrate layer.

[0008] In one embodiment, the packing hole is provided with a sealing layer at the point through the side surface, and the sealing layer is capable of melting at a first preset temperature.

[0009] In one embodiment, the foil layer is an aluminum foil layer or a copper foil layer, and the substrate layer is a polymer layer containing PET or PP.

[0010] In one embodiment, the composite foil has a thickness direction, and the connecting surface is the surface of the substrate layer perpendicular to the thickness direction; the substrate layer comprises two layers stacked and composited along the thickness direction, the two layers including a composite surface in contact, at least one of the composite surfaces of the layers having a through groove, and the filler hole is formed by the through groove in the composite state of the two layers.

[0011] In one embodiment, the through slots are multiple, each through slot is located in the same layer, or each layer has the through slots.

[0012] In one embodiment, the packing hole is formed by combining the through groove on one layer and the composite surface of the other layer; or, the through grooves are provided on the composite surfaces of the two layers at opposite positions, and the packing hole is formed by combining two through grooves that are respectively provided on the two layers.

[0013] In one embodiment, the fire extinguishing material comprises a fire extinguishing capsule; the fire extinguishing capsule comprises a capsule shell and fire extinguishing powder located inside the capsule shell, the capsule shell being capable of rupturing at a second preset temperature.

[0014] In one embodiment, the composite foil has a thickness direction, and the connecting surface is the surface of the substrate layer perpendicular to the thickness direction; the substrate layer has at least one side surface parallel to the thickness direction, the filler hole penetrates at least one side surface, and a sealing layer is provided at the point where the filler hole penetrates the side surface, the sealing layer being capable of melting at a first preset temperature; the first preset temperature is less than or equal to a second preset temperature.

[0015] This utility model also provides a battery comprising the composite foil material as described above.

[0016] In one embodiment, the two ends of the filler hole respectively penetrate the substrate layer, the battery includes a housing and an explosion-proof valve disposed in the housing, the composite foil is located inside the housing, and the explosion-proof valve is disposed at at least one end of the housing along the penetration direction of the filler hole.

[0017] The beneficial effects of this invention are as follows: The composite foil material comprises a foil layer and a polymer substrate layer. The foil layer is disposed at the connection surface of the substrate layer. The substrate layer has filler holes that do not penetrate the connection surface, and the holes are filled with fire extinguishing material. By filling the composite foil material with fire extinguishing material, the fire extinguishing material can be triggered to extinguish the fire when the battery cell made of the composite foil material experiences thermal runaway, which helps to improve the safety performance of the battery during thermal runaway. There is a gap between the filler holes and the connection surface of the substrate layer, thereby preventing the filler holes from penetrating the connection surface of the substrate layer and affecting the flatness of the composite area between the foil layer and the substrate layer, thus avoiding affecting the flatness of the foil layer and the subsequent coating of active materials. In addition, the polymer substrate layer of the composite foil material helps to improve the battery safety performance and reduce the weight of the composite foil material, thereby reducing the battery weight and increasing the battery energy density. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a cross-sectional view of the composite foil material of one embodiment of the present invention, parallel to the thickness direction;

[0020] Figure 2 This is a cross-sectional view of the composite foil material of another embodiment of the present invention, parallel to the thickness direction;

[0021] Figure 3 This is a cross-sectional view of the composite foil material of another embodiment of the present invention, parallel to the thickness direction;

[0022] Figure 4 This is an exploded view of the substrate layer of this utility model;

[0023] Figure 5 This is a cross-sectional view of the composite foil material of this utility model along the length of the filler hole at the position of the filler hole.

[0024] In the diagram: 1. Composite foil; 2. Substrate layer; 2A. Layering; 21. Filler hole; 211. Through groove; 22. Connecting surface; 23. Side surface; 24. Composite surface; 3. Foil layer; 4. Fire extinguishing material; 5. Sealing layer. Detailed Implementation

[0025] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of this utility model. Based on the description of this utility model, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this utility model.

[0026] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0027] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of description and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0029] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0030] This utility model provides a composite foil material 1, such as Figure 1 As shown, it includes a foil layer 3 and a substrate layer 2, the substrate layer 2 being a polymer layer; the substrate layer 2 has a connecting surface 22, on which the foil layer 3 is disposed; the substrate layer 2 includes a filler hole 21, with a gap between the filler hole 21 and the connecting surface 22, and the filler hole 21 is filled with fire extinguishing material 4.

[0031] In this embodiment, the composite foil 1 consists of a foil layer 3 and a polymer substrate layer 2. The foil layer 3 is disposed at the connection surface 22 of the substrate layer 2. The substrate layer 2 has filler holes 21 that do not penetrate the connection surface 22, and the holes are filled with fire extinguishing material 4. Thus, when the battery cell made of the composite foil 1 experiences thermal runaway, the fire extinguishing material 4 can be triggered to extinguish the fire, which helps improve the safety performance of the battery during thermal runaway. There is a gap between the filler holes 21 and the connection surface 22 of the substrate layer 2, thereby preventing the filler holes 21 from penetrating the connection surface 22 of the substrate layer 2 and affecting the flatness of the composite area between the foil layer 3 and the substrate layer 2, and thus avoiding affecting the flatness of the foil layer 3, which helps to avoid affecting the subsequent coating of active materials. In addition, the polymer substrate layer 2 of the composite foil 1 helps to improve the battery safety performance and reduce the weight of the composite foil 1, thereby reducing the battery weight and increasing the battery energy density.

[0032] Among them, the packing hole 21 is an elongated hole (such as...). Figures 1 to 4 As shown), its length direction is perpendicular to the thickness direction, and the cross-section of the packing hole 21 perpendicular to its own length direction can be square or circular. Specifically, the diameter of the circular cross-section is not less than 1μm, and the square cross-section can be a square with a side length of not less than 1μm, or a rectangle with a short side of not less than 1μm. This avoids the packing hole 21 being too small, thus preventing it from carrying too little extinguishing material 4.

[0033] Each packing hole 21 can be arranged in parallel, with a spacing of s between adjacent packing holes 21, where 1mm ≤ s ≤ 10mm. This avoids the packing holes 21 being too dense, which would affect processing, and also avoids the packing holes 21 being too sparse, which would affect the number of packing holes 21 and thus the storage of fire extinguishing material 4.

[0034] Specifically, the packing hole 21 can be a cylindrical hole with a cross-sectional diameter of 5μm; the spacing between adjacent packing holes 21 can be selected as 5mm.

[0035] As one implementation method, such as Figure 1 As shown, the composite foil 1 has a thickness direction D, and the connecting surface 22 is the surface of the substrate layer 2 perpendicular to the thickness direction D; along the thickness direction D, foil layers 3 are provided on both sides of the substrate layer 2, and the substrate layer 2 has two connecting surfaces 22.

[0036] As one implementation method, such as Figure 1 and Figure 4 As shown, the substrate layer 2 has at least one side surface 23 parallel to the thickness direction D, and the packing hole 21 penetrates at least one side surface 23; thereby, the fire extinguishing material 4 in the packing hole 21 can be conveniently released from the packing hole 21 when fire extinguishing is required.

[0037] As one implementation method, such as Figure 4 and Figure 5 As shown, the substrate layer 2 includes at least one filler hole 21, and the at least one filler hole 21 is filled with fire extinguishing material 4. The substrate layer 2 has at least a pair of oppositely arranged side surfaces 23, and the filler hole 21 penetrates the pair of oppositely arranged side surfaces 23 of the substrate layer 2. The design of the filler hole 21 penetrating the opposite side surfaces 23 ensures that the fire extinguishing material 4 can be released more quickly, thereby enhancing the fire extinguishing effect.

[0038] As one implementation method, such as Figures 1 to 5 As shown, the substrate layer 2 has four side surfaces 23, and the filler hole 21 penetrates two of the opposite side surfaces 23, which facilitates the rapid release of the extinguishing material 4 from both sides and the rapid response to thermal runaway; if the filler hole 21 only penetrates one side surface 23, the extinguishing material 4 will be released from that side during thermal runaway, and the release of the extinguishing material 4 will be slower.

[0039] As one implementation method, such as Figure 5 As shown, a sealing layer 5 is provided at the through-side surface 23 of the packing hole 21. The sealing layer 5 can melt at a first preset temperature. When the battery is working normally, the sealing layer 5 is used to seal the packing hole 21 to prevent the fire extinguishing material 4 from leaking; in the event of thermal runaway, the sealing layer 5 melts and triggers the fire extinguishing process.

[0040] Specifically, the sealing layer 5 can melt at a first preset temperature (e.g., 60-100°C) to release the extinguishing material 4. The sealing layer 5 may contain paraffin wax or polyethylene wax with a suitable melting point. Specifically, it may include an emulsifier that is emulsified and dispersed by heating and stirring wax, adhesive, and water. After being coated onto the side surface 23 penetrated by the filling hole 21 in the emulsified state, excess liquid on the surface is scraped off, and then it is dried and cooled to form the sealing layer 5. Under normal battery operation, the sealing layer 5 prevents the extinguishing material 4 from detaching from the filling hole 21. When the battery reaches the first preset temperature, the sealing layer 5 breaks to release the extinguishing material 4.

[0041] In one embodiment, the foil layer 3 is an aluminum foil layer or a copper foil layer, and the substrate layer 2 is a polymer layer containing PET or PP.

[0042] As one implementation, the substrate layer 2 also contains graphene and / or carbon nanotubes; graphene or carbon nanotubes have a high thermal radiation coefficient, which is beneficial for heat dissipation and reduces the risk of thermal runaway.

[0043] Specifically, the substrate layer 2 comprises PET and graphene, with a mass ratio of PET to graphene of (70:30) to (95:5), for example, a mass ratio of PET to graphene of 95:5; or the substrate layer 2 comprises PP and graphene, with a mass ratio of PP to graphene of (70:30) to (95:5); or the substrate layer 2 comprises PET and carbon nanotubes, with a mass ratio of PET to carbon nanotubes of (70:30) to (95:5); or the substrate layer 2 comprises PP and carbon nanotubes, with a mass ratio of PP to carbon nanotubes of (70:30) to (95:5).

[0044] As one implementation method, such as Figures 2 to 5 As shown, the substrate layer 2 comprises two layers 2A stacked and composited along the thickness direction D. The two layers 2A include a composite surface 24 in contact. At least one layer 2A has a through groove 211 on its composite surface 24. The filler hole 21 is formed by the through groove 211 in the composite state of the two layers 2A. By prefabricating the through groove 211 in the layers 2A (e.g., by molding or laser engraving), the direct machining of channels within a single substrate layer 2 is avoided, reducing manufacturing difficulty. The composite layer 2A also facilitates control over the shape, size, and distribution of the filler hole 21, adapting to different battery design requirements. The two layers 2A can be thermally bonded together, maintaining a certain distance between the thermally bonded portion and the filler hole 21. Alternatively, the filler hole 21 can be cooled during thermal bonding to prevent impact on the fire extinguishing material 4. After thermal bonding, a sealing layer 5 is provided to seal the fire extinguishing material 4 within the filler hole 21. The sealing layer 5 can cover the entire side surface 23 penetrated by the filler hole 21 to improve sealing performance.

[0045] As one implementation method, such as Figure 2As shown, there are multiple through slots 211, each located in the same layer 2A. Therefore, it is unnecessary to align the through slots 211 in two layers 2A, simplifying the composite process, improving production efficiency, and avoiding blockage of the filler holes 21 due to misalignment. This also reduces the number of processing steps for the through slots 211, lowering mold complexity and material waste. As another embodiment, such as... Figure 3 and Figure 4 As shown, each layer 2A has a through groove 211.

[0046] As one implementation method, such as Figure 2 As shown, the packing hole 21 is formed by combining a through groove 211 on one layer 2A and a composite surface 24 on another layer 2A; or, as Figure 3 and Figure 4 As shown, through grooves 211 are provided on the composite surfaces 24 of the two layers 2A at opposite positions. The filler hole 21 is formed by two through grooves 211 that are respectively provided on the two layers 2A. In this way, the two layers 2A are symmetrically arranged, which is beneficial to the structural stability of the composite foil 1.

[0047] In one embodiment, the fire extinguishing material 4 comprises a fire extinguishing capsule (not shown); the fire extinguishing capsule comprises a capsule shell (not shown) and fire extinguishing powder (not shown) located inside the capsule shell, the capsule shell being capable of rupturing at a second preset temperature; the fire extinguishing powder is one or more of sodium bicarbonate, modified sodium salt, baking soda, ammonium carbonate, and ammonium phosphate, and the capsule shell is one of polyvinyl alcohol shell, polyamide shell, polystyrene shell, polyester shell, or epoxy resin shell. Specifically, the capsule shell ruptures at a second preset temperature (e.g., the battery thermal runaway initiation temperature, 100°C), releasing the fire extinguishing powder to extinguish the fire; the capsule shell ruptures at a specific second preset temperature to avoid premature or delayed release of the fire extinguishing powder, ensuring accurate timing of fire extinguishing; the capsule encapsulation prevents the fire extinguishing powder from becoming ineffective, and after rupture, the powder quickly covers the burning area, extinguishing the fire through mechanisms such as decomposition and heat absorption, and oxygen isolation. Wherein, the first preset temperature ≤ the second preset temperature.

[0048] This invention also provides a battery (not shown) comprising a composite foil 1 as described above. The composite foil 1 is used to make electrode sheets. This invention achieves fire extinguishing at the electrode sheet level, thereby improving overall safety.

[0049] As one implementation method, such as Figure 5As shown, the composite foil 1 includes a tab (not shown), with the thickness direction D being horizontal, and the tab located at the bottom of the composite foil 1. A filler hole 21 is vertically arranged and penetrates at least downwards through the substrate layer 2 along the vertical direction H. The vertically arranged filler hole 21 reduces resistance to the falling and released extinguishing material 4. The filler hole 21 can avoid the external welding points of the tab, and at least part of the filler hole 21 penetrates the bottom of the substrate layer 2 where no tab is provided. Specifically, the tab is a high-risk area for battery thermal runaway (current concentration easily generates heat). Since the tab is located at the bottom of the composite foil 1, in the event of thermal runaway, the extinguishing material 4 can quickly fall from the filler hole 21 at the bottom of the substrate layer 2 under gravity to the vicinity of the tab, which helps improve extinguishing efficiency and ensures a rapid response in the early stages of a fire at the tab.

[0050] In one embodiment, the two ends of the packing hole 21 penetrate the substrate layer 2, the battery includes a housing (not shown) and an explosion-proof valve (not shown) disposed in the housing, the composite foil 1 is located inside the housing, and the explosion-proof valve is disposed at at least one end of the housing along the penetration direction of the packing hole 21. Therefore, after the extinguishing material 4 is released, the packing hole 21 can serve as an air passage, facilitating the release of air and pressure from inside the battery to the explosion-proof valve for explosion prevention, thus improving safety performance.

[0051] As one implementation method, such as Figure 5 As shown, the filler hole 21 penetrates the substrate layer 2 at both ends along the vertical direction H. The battery includes a housing and an explosion-proof valve disposed in the housing. The composite foil 1 is located inside the housing, and the explosion-proof valve is disposed at the bottom of the housing along the vertical direction H.

[0052] The beneficial effects of this invention are as follows: The composite foil 1 is composed of a foil layer 3 and a polymer substrate layer 2. The foil layer 3 is disposed at the connection surface 22 of the substrate layer 2. The substrate layer 2 has a filler hole 21 that does not penetrate the connection surface 22, and the hole is filled with fire extinguishing material 4. Thus, when the battery cell made of the composite foil 1 experiences thermal runaway, the fire extinguishing material 4 can be triggered to extinguish the fire, which helps to improve the safety performance of the battery during thermal runaway. There is a gap between the filler hole 21 and the connection surface 22 of the substrate layer 2, thereby preventing the filler hole 21 from penetrating the connection surface 22 of the substrate layer 2 and affecting the flatness of the composite area between the foil layer 3 and the substrate layer 2, and thus avoiding affecting the flatness of the foil layer 3, which helps to avoid affecting the subsequent coating of active materials. In addition, the polymer substrate layer 2 of the composite foil 1 helps to improve the battery safety performance and reduce the weight of the composite foil 1, thereby reducing the battery weight and increasing the battery energy density.

[0053] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the present utility model's technical solution. These are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model's technical solution shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A composite foil material, characterized in that, It includes a foil layer (3) and a substrate layer (2), wherein the substrate layer (2) is a polymer layer; the substrate layer (2) has a connecting surface (22), and the foil layer (3) is disposed on the connecting surface (22) of the substrate layer (2); the substrate layer (2) includes a filler hole (21), and there is a gap between the filler hole (21) and the connecting surface (22), wherein the filler hole (21) is filled with fire extinguishing material (4).

2. The composite foil as described in claim 1, characterized in that, The composite foil (1) has a thickness direction (D), and the connecting surface (22) is a surface of the substrate layer (2) perpendicular to the thickness direction (D); the substrate layer (2) has at least one side surface (23) parallel to the thickness direction (D), and the filler hole (21) penetrates at least one side surface (23).

3. The composite foil material as described in claim 2, characterized in that, The substrate layer (2) includes at least one of the filling holes (21), the at least one of the filling holes (21) is filled with fire extinguishing material (4), the substrate layer (2) has at least a pair of opposing side surfaces (23), and the filling hole (21) penetrates the pair of opposing side surfaces (23) of the substrate layer (2).

4. The composite foil as described in claim 2, characterized in that, The filling hole (21) is provided with a sealing layer (5) at the point through the side surface (23), and the sealing layer (5) can melt at a first preset temperature.

5. The composite foil as described in claim 1, characterized in that, The foil layer (3) is an aluminum foil layer or a copper foil layer, and the substrate layer (2) is a polymer layer containing PET or PP.

6. The composite foil as described in any one of claims 1 to 5, characterized in that, The composite foil (1) has a thickness direction (D), and the connecting surface (22) is the surface of the substrate layer (2) perpendicular to the thickness direction (D); the substrate layer (2) includes two layers (2A) stacked and composited along the thickness direction (D), the two layers (2A) include a composite surface (24) in contact, and at least one of the composite surfaces (24) of the layers (2A) is provided with a through groove (211), and the filler hole (21) is formed by the through groove (211) in the composite state of the two layers (2A).

7. The composite foil as described in claim 6, characterized in that, The through slots (211) are multiple, and each through slot (211) is located in the same layer (2A), or each layer (2A) has the through slot (211).

8. The composite foil as described in claim 6, characterized in that, The packing hole (21) is formed by combining the through groove (211) on one layer (2A) and the composite surface (24) of the other layer (2A); or, the through groove (211) is provided on the composite surface (24) of the two layers (2A) at opposite positions, and the packing hole (21) is formed by combining the two through grooves (211) that are respectively provided on the two layers (2A).

9. The composite foil as described in any one of claims 1 to 5, characterized in that, The fire extinguishing material (4) includes a fire extinguishing capsule; the fire extinguishing capsule includes a capsule shell and fire extinguishing powder located inside the capsule shell, and the capsule shell can rupture at a second preset temperature.

10. The composite foil as described in claim 9, characterized in that, The composite foil (1) has a thickness direction (D), and the connecting surface (22) is the surface of the substrate layer (2) perpendicular to the thickness direction (D); the substrate layer (2) has at least one side surface (23) parallel to the thickness direction (D), the filler hole (21) penetrates at least one side surface (23), and the filler hole (21) is provided with a sealing layer (5) at the point where it penetrates the side surface (23), and the sealing layer (5) is capable of melting at a first preset temperature; the first preset temperature is less than or equal to the second preset temperature.

11. A battery, characterized in that, It includes the composite foil (1) as described in any one of claims 1-10.

12. The battery as claimed in claim 11, characterized in that, The two ends of the filler hole (21) respectively penetrate the substrate layer (2), the battery includes a housing and an explosion-proof valve disposed in the housing, the composite foil (1) is located inside the housing, and the explosion-proof valve is disposed at at least one end of the housing along the penetration direction of the filler hole (21).

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