Battery cell, heat-shrinkable film, battery device, and electric device

Abstract

The application relates to a battery monomer, a heat-shrinkable film, a battery device and a power utilization device. The battery monomer comprises: an electric core with two large surfaces oppositely arranged in a first direction. The heat-shrinkable film is wrapped around the electric core and comprises a base film and a buffer, the base film has a first side and a second side oppositely arranged in the first direction and respectively attached to the two large surfaces of the electric core, and at least one layer of the buffer is arranged on the outer surface of the first side and / or the second side. Thus, the battery monomer with the heat-shrinkable film integrates the buffer and the base film, when a plurality of battery monomers are stacked, the buffer layer does not need to be additionally placed, the position of the buffer is stable, the uniformity of the interlayer support can be ensured, the buffer is not prone to wrinkles and has uniform thickness, the overall large surface flatness can be improved, the stacked multiple battery monomers are stable and are not prone to skewing, and the subsequent assembly is facilitated.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, heat-shrink films, battery devices, and electrical devices. Background Technology

[0002] With the rapid development of new energy vehicle technology, the power battery system, as a core component, directly determines the performance of the entire vehicle through its energy density, safety, and cycle life. Among various packaging forms, pouch batteries have become an important choice for electric vehicles due to their advantages such as lightweight aluminum-plastic film casing, compact internal winding or stacked structure, and high energy density. To meet the high voltage and large capacity requirements of electric vehicles, multiple cells are typically stacked and connected in series and parallel to form a battery pack.

[0003] In the process of stacking multiple battery cells, separate buffer layers such as foam boards, cardboard, and air cushion films are usually placed between the cells. Because the buffer layers are separate from the cells, they are prone to shifting or misaligning relative to the cells during stacking, resulting in uneven interlayer support. Moreover, thinner buffer layers are prone to wrinkling during placement, leading to poor overall flatness of the stacked multi-layer cells, which can cause skewing and affect subsequent assembly. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, heat shrink film, battery device and power device, which can improve the problem that buffers are prone to displacement, shifting and wrinkling during the multi-cell stacking process, resulting in uneven interlayer support and poor overall surface flatness.

[0005] In a first aspect, this application provides a battery cell, the battery cell comprising:

[0006] The battery cell has two large surfaces disposed opposite each other in a first direction;

[0007] A heat-shrinkable film is used to cover the battery cell. The heat-shrinkable film includes a base film and a buffer. The base film has a first side and a second side that are disposed opposite to each other in the first direction and respectively adhere to the two large surfaces. At least one layer of the buffer is disposed on the outer surface of the first side and / or the second side.

[0008] The battery cell provided in this application embodiment, by setting the cell and heat shrink film, has at least one layer of buffer material on the outer surface of the first side and / or the second side of the bonding surface of the heat shrink film. In this way, the heat shrink film integrates the buffer material, so when stacking multiple battery cells, there is no need to place an additional buffer layer. The position of the buffer material is stable, which can ensure the uniformity of interlayer support. Moreover, the buffer material is not easy to wrinkle and has a uniform thickness, which can improve the flatness of the overall surface, make the stacking stable, and not easy to be skewed, which is beneficial to subsequent assembly.

[0009] In some other embodiments, the large surface of the battery cell is located within the coverage area of ​​the orthographic projection of the buffer in the first direction.

[0010] The battery cell provided in this application embodiment has its large surface circumferential edge located inside the circumferential edge of the buffer. This allows the buffer to completely cover the large surface of the battery cell, ensuring the contact area between the buffer and other battery cells, providing effective support, and enabling the stacking pressure to be evenly distributed, which is beneficial to improving the flatness of the large surface after multiple battery cells are stacked.

[0011] In some other embodiments, the buffer is located within the coverage area of ​​the orthographic projection of the large surface of the battery cell in a first direction.

[0012] The battery cell provided in this application embodiment has a buffer component located within the coverage area of ​​the orthographic projection of the large surface of the cell in the first direction. This ensures that the edge of the buffer component is flush with the edge of the large surface of the cell or located inside the edge of the large surface of the cell. This allows the buffer component to provide a buffering effect between battery cells and prevents the buffer component from occupying the lateral space of the cell.

[0013] In some other embodiments, the distance between the circumferential edge of the buffer and the circumferential edge of the large surface of the battery cell is less than or equal to 2 mm.

[0014] The battery cell provided in this application embodiment ensures effective support by setting the distance between the circumferential edge of the buffer and the circumferential edge of the large surface of the cell to be less than or equal to 2mm, thereby ensuring the contact area between the buffer and other battery cells, allowing the stacking pressure to be evenly distributed, and also improving the flatness of the large surface after multiple battery cells are stacked.

[0015] In some other embodiments, the buffer covers the large surface of the battery cell and at least a portion of the side surface of the battery cell.

[0016] The battery cell provided in this application embodiment includes a buffer that covers the large surface of the cell and at least part of the side surface of the cell. This buffer can isolate the corners of adjacent cells when multiple battery cells are stacked, preventing the corners from bumping or squeezing each other. It can also provide cushioning on the side surface of the cell.

[0017] Secondly, this application provides a heat-shrinkable film suitable for the battery cell in any of the above embodiments, the heat-shrinkable film comprising:

[0018] A substrate film having a first side and a second side disposed opposite to each other in a first direction and both used to adhere to the large surface of the battery cell;

[0019] A buffer member, wherein at least one layer of the buffer member is provided on the outer surface of the first side and / or the second side.

[0020] The heat shrink film provided in this application embodiment has a base film and a buffer. The base film has a first side and a second side that are arranged opposite to each other in a first direction and are both used to adhere to the large surface of the battery cell. At least one buffer is provided on the outer surface of the first side and / or the second side. In this way, the buffer and the base film are integrated into one piece. When stacking battery cells, there is no need to place an additional buffer layer. The position of the buffer is stable, which can ensure the uniformity of interlayer support. The buffer is not prone to wrinkles and has a uniform thickness, which can improve the overall flatness of the large surface. The stacking of multiple battery cells is stable and not prone to skewing, which is beneficial to subsequent assembly.

[0021] In some other embodiments, the buffer is adhesively attached to the substrate membrane.

[0022] The heat shrink film provided in this embodiment has a buffer component that is bonded to the base film. The large connection area between the buffer component and the base film results in high bonding strength, which helps to improve the connection stability.

[0023] In some other embodiments, the buffer is a foam pad, a rubber pad, a buffer film, or a composite thermal insulation buffer pad.

[0024] The heat shrink film provided in this application embodiment can be selected as a foam pad, rubber pad, buffer film or composite heat insulation buffer pad, so that the buffer has good buffering performance, and also has at least one of the functions of insulation, heat insulation and flame retardancy.

[0025] In some other embodiments, the battery cell is a pouch solid-state battery cell, and the thickness of the buffer is 5μm-30μm.

[0026] The heat shrink film provided in this application embodiment has a buffer thickness of 5μm-30μm for soft-pack solid-state batteries, which keeps the buffer thin, thus not only achieving the buffering effect but also saving space.

[0027] In some other embodiments, the battery cell is a pouch liquid battery cell, and the thickness of the buffer is 3mm-5mm.

[0028] The heat shrink film provided in this application embodiment, with a buffer thickness of 3mm-5mm for soft-pack liquid battery cells, can provide a large buffer stroke, effectively absorb expansion force, and homogenize the pressure distribution between the central and edge areas, avoiding excessive local stress.

[0029] In some other embodiments, the buffer is constructed as a flat plate structure.

[0030] The heat shrink film provided in this application embodiment has good spatial fit by using a flat buffer structure, which can maximize the use of the gap between the two battery cells and reduce space waste.

[0031] In some other embodiments, the substrate film is configured as a bag-shaped structure with one end open in a second direction, which is the tab lead-out direction of the battery cell.

[0032] The heat shrink film provided in this embodiment, by adopting a bag-shaped base film, can fully wrap the battery cell after heating and shrinking, providing continuous and uniform pre-tightening force to the battery cell and achieving the effects of moisture-proof, waterproof and insulation.

[0033] In some other embodiments, the substrate film is constructed as a cylindrical structure with openings at both opposite ends in a second direction, the second direction being the tab lead-out direction of the battery cell.

[0034] The heat shrink film provided in this embodiment is open at both ends in the second direction, so the expansion of the battery cell in the first direction is not constrained by the heat shrink film at the ends in the second direction, thus avoiding tearing of the heat shrink film.

[0035] In some other embodiments, the outer surfaces of the first side and / or the second side are provided with multiple layers of the buffer members, which are stacked in the first direction.

[0036] The heat shrink film provided in this embodiment can be provided with multiple layers of buffers on the outer surface of the first side and / or the second side. The multiple layers of buffers are stacked in the first direction to form a gradient energy absorption structure, which can improve the impact resistance and extend the life of the buffering effect.

[0037] Thirdly, this application provides a battery device, which includes a battery cell as described in any of the above embodiments.

[0038] Fourthly, this application provides an electrical device including a battery device as described in any of the above embodiments, the battery device being used to provide electrical energy.

[0039] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0040] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0041] Figure 1 This is a three-dimensional structural diagram of the heat shrink film according to some embodiments of this application;

[0042] Figure 2 for Figure 1 A side view of the heat-shrinkable film along the Y direction;

[0043] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle;

[0044] Figure 4 This is a three-dimensional structural diagram of a battery cell according to some embodiments of this application;

[0045] Figure 5 for Figure 4 A schematic diagram of the cross-sectional structure of a single battery cell along the X direction;

[0046] Figure 6 for Figure 5 A magnified view of a portion of point B in the middle;

[0047] Figure 7 This is a schematic diagram of the structure of multi-cell stacking in some embodiments of this application;

[0048] Figure 8 This is an exploded view of the battery device according to some embodiments of this application;

[0049] Figure 9 This is a schematic diagram of the structure of a vehicle according to some embodiments of this application.

[0050] The reference numerals in the detailed embodiments are as follows:

[0051] 1000, vehicles;

[0052] 100. Battery assembly; 200. Controller; 300. Motor;

[0053] 10. Box body; 11. First part; 12. Second part;

[0054] 20. Battery cell; 21. Cell; 210. Large surface area; 211. Casing; 212. Electrode assembly; 2121. Positive electrode; 2122. Negative electrode; 2123. Solid electrolyte layer; 213. Tab; 22. Heat shrink film; 221. Substrate film; 2211. First side; 2212. Second side; 222. Buffer. Detailed Implementation

[0055] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0057] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0058] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0059] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0060] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0061] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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 the embodiments of this application.

[0062] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0063] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0064] Among various packaging forms, pouch cells have become an important choice for electric vehicles due to their advantages such as lightweight aluminum-plastic film casing, compact internal winding or stacked structure, and high energy density. To meet the high voltage and large capacity requirements of electric vehicles, multiple individual cells are usually stacked and combined in series and parallel to form a battery pack.

[0065] The inventors of this application have noticed that during the multi-cell stacking process, separate buffer layers such as foam boards, cardboard, and air cushion films are usually placed between the cells. Because the buffer layers are separate from the cells, they are prone to shifting or misaligning during stacking. Moreover, thinner buffer layers are prone to wrinkling when placed, resulting in uneven interlayer support, poor overall flatness of the stacked multi-cell surface, and a tendency for skewing.

[0066] Furthermore, when the stacked cells are pressed and tightened later, the wrinkled buffer layer may cause the electrode to break. In addition, during normal charging and discharging, uneven interlayer support may cause the electrode to not adhere tightly to the electrolyte interface, affecting the reliability of the cell's service life.

[0067] Based on the above considerations, to address the issues of buffer components easily shifting, displacing, and wrinkling during multi-cell stacking, leading to uneven interlayer support and poor overall surface flatness, the inventors, through in-depth research, designed a battery cell comprising a cell and a heat-shrinkable film. The cell has two large surfaces arranged opposite each other in a first direction. The heat-shrinkable film includes a base film and a buffer component. The base film has a first side and a second side arranged opposite each other in the first direction and respectively attached to the two large surfaces of the cell. At least one layer of buffer component is disposed on the outer surface of the first side and / or the second side. Thus, the buffer component and the base film are integrated into one unit. Therefore, when stacking battery cells using this heat-shrinkable film, there is no need to place an additional buffer layer. The position of the buffer component is stable, ensuring uniform interlayer support. Furthermore, the buffer component is less prone to wrinkling and has a uniform thickness, improving the overall surface flatness, ensuring stable stacking, reducing the likelihood of skewing, and facilitating subsequent assembly.

[0068] Furthermore, because the heat-shrink film integrates a buffer, there is no need for a separate buffer. This reduces the likelihood of wrinkles forming in the buffer, preventing damage to the electrodes when multiple stacked cells are pressed together. For solid-state cells, this also ensures a tighter fit between the electrodes and the electrolyte interface, improving the reliability of the cell during operation.

[0069] The heat shrink film, battery cell, battery device, and power device provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0070] See Figures 1 to 5 , Figure 1 This is a schematic diagram of the structure of the heat shrink film 22 in some embodiments of this application. Figure 2 for Figure 1 A side view of the heat-shrinkable film 22 along the Y direction. Figure 3 for Figure 2 A magnified view of a portion of point A in the middle. Figure 4 This is a schematic diagram of the structure of a battery cell 20 according to some embodiments of this application. Figure 5 for Figure 4 A schematic diagram of the cross-sectional structure of the battery cell 20 along the X direction.

[0071] This application provides a heat-shrinkable film 22, which includes a base film 221 and a buffer member 222. The base film 221 has a first side portion 2211 and a second side portion 2212 disposed opposite to each other in a first direction and both used for bonding to the large surface 210 of the battery cell 21. At least one layer of buffer member 222 is disposed on the outer surface of the first side portion 2211 and / or the second side portion 2212. Wherein, the first direction is as follows: Figure 1 The X direction is shown in the diagram.

[0072] The heat-shrink film 22 is used to cover the battery cell 21. The first side 2211 and the second side 2212 of the substrate film 221 are respectively attached to the two large surfaces 210 of the battery cell 21. That is, the two large surfaces 210 of the battery cell 21 are arranged opposite each other in the first direction, and the battery cell 21 is located between the first side 2211 and the second side 2212 in the first direction. At this time, the buffer member 222 is located outside the large surface 210 of the battery cell 21. When multiple battery cells 20 are stacked, the buffer member 222 contacts the buffer member 222 outside another battery cell 21, and the two buffer members 222 together play a supporting and buffering role.

[0073] Here, the large surface 210 of cell 21 refers to the largest and flattest surface of cell 21. When stacking multiple battery cells 20, the large surfaces 210 of two adjacent cells 21 are arranged opposite each other.

[0074] Optionally, a buffer 222 can be provided on the outer surface of the first side 2211 or the second side 2212. In this way, the battery cell 20 using the heat-shrinkable film 22 can be located at the bottom layer when stacked, with the buffer 222 facing upwards and contacting the buffer 222 of the heat-shrinkable film 22 of the upper battery cell 20. Alternatively, it can be located at the top layer, with the buffer 222 facing downwards and contacting the buffer 222 of the heat-shrinkable film 22 of the lower battery cell 20. Of course, buffers 222 can be provided on the outer surfaces of both the first side 2211 and the second side 2212. In this case, the battery cell 20 using the heat-shrinkable film 22 can contact the upper and lower battery cells 20 respectively through the buffers 222 on both sides when stacked.

[0075] The heat-shrink film 22 provided in this embodiment, by setting a base film 221 and a buffer 222, has a first side 2211 and a second side 2212 arranged opposite to each other in a first direction and both used to adhere to the large surface 210 of the battery cell 21. At least one layer of buffer 222 is provided on the outer surface of the first side 2211 and / or the second side 2212. Thus, the buffer 222 and the base film 221 are integrated into one unit. When stacking the battery cells 20, no additional buffer layer is needed. The position of the buffer 222 is stable, ensuring the uniformity of interlayer support. Furthermore, the buffer 222 is less prone to wrinkles and has a uniform thickness, improving the overall flatness of the large surface. This makes the stacking of multiple battery cells 20 stable and less prone to skewing, which is beneficial for subsequent assembly. The subsequent assembly process involves applying pressure, clamping, and fixing the stacked multiple battery cells 20.

[0076] Understandably, the buffer 222 is integrated on the heat-shrink film 22, and the heat-shrink film 22 covers the cell 21 to form a battery cell 20. In this way, when the battery cells 20 are stacked, the buffer 222 is restricted by the connection and fixation of the base film 221, and is not easy to form wrinkles due to bending, folding, etc. In this way, the thickness of the buffer 222 remains unchanged, thereby making the overall flatness of the large surface better when multiple battery cells 20 are stacked, and thus less likely to be skewed.

[0077] Furthermore, the buffer 222 can also serve as an external protective layer for the battery cell 20, providing a certain level of protection. When stacking the battery cells 20, the process of placing a separate buffer layer can be eliminated, thereby reducing process and material costs and management difficulties, which is conducive to automated production.

[0078] In some embodiments, the buffer 222 is a foam pad, a rubber pad, a buffer film, or a composite thermal insulation buffer pad.

[0079] The cushioning element 222 can be selected as a foam pad, which not only gives the cushioning element 222 good cushioning performance, but also the foam has excellent flame retardant, high temperature resistance and insulation properties, and also has the functions of heat insulation, flame retardancy and insulation. The foam pad can be selected from, but is not limited to, foamed polymer foam, such as polyurethane foam, cross-linked polyethylene foam (including chemically cross-linked (XPE) foam, electron irradiation associated (IXPE) foam), etc., without specific limitations.

[0080] The buffer element 222 can be selected as a rubber gasket, which not only gives the buffer element 222 good cushioning performance, but also the rubber has excellent flame retardant, high temperature resistance, and insulation properties, thus providing heat insulation, flame retardant, and insulation functions. Its wear resistance can also extend its service life. The material of the rubber gasket can be selected, but is not limited to, silicone rubber, acrylic rubber, nitrile rubber, etc.

[0081] The buffer element 222 can be selected as a buffer film, which can absorb stress by utilizing its good flexibility and extensibility, and also has the functions of heat insulation, flame retardancy and insulation. The buffer film can be selected, but is not limited to, PET (polyester film), PP (polypropylene film), PE (polyethylene film), etc.

[0082] Among them, the buffer element 222 can be selected as a composite heat-insulating buffer pad, which not only gives the buffer element 222 good cushioning performance, but also has the functions of heat insulation, flame retardancy and insulation. The material of the composite heat-insulating buffer pad can be selected but is limited to silicone foam cotton, aerogel composite buffer film (such as combined with ceramic fiber, glass fiber substrate, etc.).

[0083] In some embodiments, the buffer 222 is bonded to the substrate membrane 221.

[0084] When the buffer element 222 is selected as a foam pad or a rubber pad, it can be fixed to the base film 221 by hot melt adhesive and roller pressing. When the buffer element 222 is a buffer film, it can be fixed to the base film 221 by solvent-free adhesive and low-temperature (e.g., 40℃-55℃) roller pressing (e.g., 0.08Mpa-0.15Mpa). When the buffer element 222 is a composite heat-insulating buffer pad, it can be fixed to the base film 221 by solvent-free adhesive and low-temperature (e.g., 40℃-55℃) roller pressing (e.g., 0.05Mpa-0.10Mpa).

[0085] The buffer element 222 is connected to the base membrane 221 by adhesive bonding. The buffer element 222 and the base membrane 221 have a large connection area and high bonding strength, which is beneficial to improving the connection stability between the buffer element 222 and the base membrane 221.

[0086] Of course, in other embodiments, the buffer 222 and the base film 221 can be fixed by heat sealing depending on the material of the buffer 222.

[0087] In some embodiments, refer to Figure 2 and Figure 3 Cell 21 is a soft-pack solid-state cell, and the thickness d of buffer 222 is 5μm-30μm.

[0088] Among them, soft-pack solid-state cells refer to cells with soft-pack casings, such as aluminum-plastic film casings, and solid electrolytes. In this case, the thickness d of the buffer 222 is set to 5μm-30μm, so that the buffer 222 maintains a relatively thin thickness, which not only achieves the buffering effect, but also saves space.

[0089] It should be noted that the electrodes inside the solid-state battery cell are in solid-solid contact with the solid electrolyte. During charging, slight lattice expansion and contraction will occur, generating interfacial stress at the nanometer to micrometer level. A buffer component 222 with a thickness of 5μm-30μm is sufficient to achieve the buffering effect.

[0090] Specifically, the thickness d of the buffer 222 can be selected as 5μm, 10μm, 15μm, 20μm, 25μm or 30μm, or other reasonable values, without specific limitations here.

[0091] Of course, in other embodiments, the battery cell can also be a pouch liquid battery cell, and the thickness of the buffer is 3mm-5mm.

[0092] Herein, the pouch-type liquid cell refers to a cell whose outer casing is a pouch outer casing, for example, an aluminum-plastic film is used as the outer casing, and a liquid electrolyte is adopted at the same time. The liquid electrolyte may be, for example, an organic liquid electrolyte, an aqueous liquid electrolyte, or the like. In this case, the pouch-type liquid cell will undergo significant volume expansion during charging and discharging. Setting the thickness of the buffer member to 3mm-5mm can provide a large buffer stroke, effectively absorb the expansion force, and can also homogenize the pressure distribution in the central region and the boundary region, avoiding excessive local stress.

[0093] Specifically, the thickness of the buffer member may be selected as 3mm, 3.5mm, 4mm, 4.5mm or 5mm, and certainly other reasonable values may also be selected, which is not specifically limited herein.

[0094] In some embodiments, refer to Figure 2 and Figure 3 , the buffer member 222 is configured as a flat plate-like structure.

[0095] Herein, the flat plate-like structure refers to two opposite and parallel planes in the thickness direction, that is, the first direction. At this time, the thickness of the buffer member 222 in the first direction is uniform, and the surface is flat.

[0096] By adopting the flat plate-shaped buffer member 222, the buffer member 222 has good space fit, can maximize the use of the gap between the two battery cells 20, and reduce space waste.

[0097] Certainly, in other embodiments, the buffer member may also be configured as a stepped structure. For example, the buffer member has two stepped planes, which are defined as a first stepped surface and a second stepped surface. The first stepped surface is farther away from the base film relative to the second stepped surface. In this way, when a plurality of cells are stacked, the two buffer members cooperate with each other, the first stepped surface of one buffer member contacts the second stepped surface of the other buffer member, so that the stepped buffer members can also be used to realize butting and limiting of the two cells.

[0098] Alternatively, at least one through hole may be further opened in the buffer member in the first direction, for example, the buffer member is configured as a "mouth"-shaped structure, a "tian"-shaped structure, etc., that is, the buffer member is provided as a structure with an opening, which can deform in a limited space, providing sufficient reserved space to cope with the expansion of the cell.

[0099] In some embodiments, refer to Figure 1 and Figure 4 , the base film 221 is configured as a bag-shaped structure with an opening at one end in the second direction, and the second direction is the tab leading-out direction of the cell 21. Herein, the first direction is the X direction as shown in Figure 1 and Figure 4 , and the second direction is as shown in Figure 1 and Figure 4The Y direction is shown in the diagram. Specifically, the first and second directions are perpendicular.

[0100] The bag-shaped structure has an opening for the power supply core 21 to enter, while the tabs 213 of the power supply core 21 are led out through the opening.

[0101] By using a bag-shaped heat-shrink film 22, the heat-shrink film 22 can wrap the battery cell 21 in all directions after being heated and shrunk, providing the battery cell 21 with a continuous and uniform pre-tightening force, and achieving the effects of moisture-proof, waterproof and insulation.

[0102] Of course, in other embodiments, the substrate film may also be configured as a cylindrical structure with openings at both ends opposite each other in a second direction, the second direction being the direction in which the electrode leads out of the battery cell. Specifically, the first direction and the second direction are perpendicular to each other.

[0103] The cylindrical structure has an opening for the battery cell to enter, while the battery cell's tabs are led out through one of the openings. By using a cylindrical heat-shrink film, after heating and shrinking, the expansion of the battery cell in the first direction is not constrained by the heat-shrink film at the ends in the second direction because both ends are open in the second direction, thus avoiding tearing of the heat-shrink film.

[0104] In some embodiments, refer to Figure 2 and Figure 3 A buffer layer 222 is provided on the outer surface of the first side portion 2211 and / or the second side portion 2212. This reduces the space occupied by the buffer layer 222, which is beneficial for reducing the height when multiple battery cells 20 are stacked.

[0105] Of course, in other embodiments, the outer surface of the first side and / or the second side is provided with multiple layers of buffer members, which are stacked in the first direction. Adjacent buffer members can be bonded together.

[0106] By setting up multiple layers of buffer components, which are stacked in the first direction, a gradient energy absorption structure can be formed, improving impact resistance and extending the lifespan of the buffering function.

[0107] The heat shrink film provided in this application embodiment refers to... Figures 1 to 5 The heat-shrink film 22 includes a base film 221 and a buffer member 222. The base film 221 has a first side portion 2211 and a second side portion 2212, which are disposed opposite each other in a first direction and are both used to adhere to the large surface 210 of the battery cell 21. A buffer member 222 is provided on the outer surface of both the first side portion 2211 and the second side portion 2212. The first direction is as follows: Figure 1 and Figure 4 The X direction is shown in the diagram.

[0108] After the substrate film 221 covers the battery cell 21, the first side 2211 and the second side 2212 of the substrate film 221 are respectively attached to the two large surfaces 210 of the battery cell 21, that is, the battery cell 21 is located between the first side 2211 and the second side 2212 in the first direction. At this time, the buffer 222 is located outside the large surface 210 of the battery cell 21. When stacking multiple battery cells 20, there is no need to place an additional buffer layer. The position of the buffer 222 is stable, which can ensure the uniformity of interlayer support. Moreover, the buffer 222 is not prone to wrinkles and has a uniform thickness, which can improve the overall flatness of the large surface. Thus, the stacking of multiple battery cells 20 is stable and not prone to skewing, which is beneficial to subsequent assembly.

[0109] Furthermore, when stacking 20 individual battery cells, the process of placing a separate buffer layer can be eliminated, thereby reducing process and material costs and management difficulty, which is conducive to automated production.

[0110] This application provides a battery cell 20, which refers to the smallest unit that makes up the battery device 100. In this embodiment, the battery cell 20 can be a pouch solid-state battery or a pouch liquid battery.

[0111] In some embodiments, please refer to Figure 4 and Figure 5 and further refer to Figure 6 and Figure 7 . Figure 6 for Figure 5 A magnified view of a portion of point B in the middle. Figure 7 This is a schematic diagram of the structure of a multi-cell stack 20 according to some embodiments of this application.

[0112] This application provides a battery cell 20, which is selected as a pouch solid-state battery. The battery cell 20 includes a heat-shrink film 22 and a cell 21. The cell 21 includes a casing 211 and an electrode assembly 212. The electrode assembly 212 is composed of alternating stacks of a positive electrode 2121, a solid electrolyte layer 2123, and a negative electrode 2122. The electrode assembly 212 is housed within a sealed cavity formed by the casing 211.

[0113] Among them, the outer shell 211 is a soft-pack outer shell. The material of the soft-pack outer shell is not limited. For example, it can be an aluminum-plastic film. The aluminum-plastic film has a three-layer composite structure, consisting of a substrate layer, a barrier layer, and a heat-sealing layer. The substrate layer is usually made of nylon or PET (polyethylene terephthalate) film, the barrier layer is mostly made of high-purity aluminum foil, and the heat-sealing layer is usually made of modified polypropylene (CPP).

[0114] The solid electrolyte layer 2123 can be made of polymer solid electrolytes, such as polyethylene oxide, polyvinylidene fluoride, and other polymer systems. It can also be made of oxide solid electrolytes, such as crystalline oxides and glassy oxides. Alternatively, it can be made of sulfide solid electrolytes.

[0115] Furthermore, both the positive electrode 2121 and the negative electrode 2122 are provided with tabs 213 extending outward from the sealing edge of the outer casing 211. Thus, the battery cell 21 has two large, oppositely arranged surfaces 210 in a first direction, and the second direction is the tab extension direction. The first and second directions are perpendicular. The first direction is as follows: Figure 4 The X direction is shown, and the second direction is as follows: Figure 4 Y direction shown in .

[0116] Combination Figures 5 to 7 As shown, the battery cell 20 includes a cell 21 and the aforementioned heat-shrink film 22. The cell 21 has two large surfaces 210 arranged opposite each other in a first direction. The heat-shrink film 22 covers the cell 21 and includes a base film 221 and a buffer 222. The base film 221 has a first side portion 2211 and a second side portion 2212 arranged opposite each other in the first direction and respectively attached to the two large surfaces 210. At least one layer of buffer 222 is provided on the outer surface of the first side portion 2211 and the second side portion 2212.

[0117] Thus, when multiple battery cells 20 are stacked, the buffer 222 of the upper battery cell 20 and the buffer 222 of the lower battery cell 20 are in contact. The direction in which the multiple battery cells 20 are stacked is the first direction, which is the vertical direction. That is to say, the multiple battery cells 20 are stacked sequentially from bottom to top.

[0118] In this embodiment, the battery cell 20 adopts the heat shrink film 22 provided in this application embodiment. The heat shrink film 22 integrates a buffer 222. Thus, when stacking the battery cells 20, there is no need to place an additional buffer layer. The position of the buffer 222 is stable, which can ensure the uniformity of interlayer support. Moreover, the buffer 222 is fixed as a whole with the heat shrink film 22 and the cell 21, which is not easy to wrinkle and has uniform thickness, which can improve the flatness of the overall surface. The stacking of multiple battery cells 20 is stable and not easy to be skewed, which is beneficial to subsequent assembly.

[0119] In some embodiments, the large surface 210 of the battery cell 21 is located within the coverage area of ​​the orthographic projection of the buffer 222 in the first direction.

[0120] Understandably, see Figure 5 and Figure 6 The circumferential edge of the large surface 210 of the battery cell 21 is located inside the circumferential edge of the buffer 222. This ensures that the buffer 222 completely covers the large surface 210 of the battery cell 21, guaranteeing the contact area between the buffer 222 and other battery cells 20, providing effective support, and allowing the stacking pressure to be evenly distributed, which is beneficial to improving the flatness of the large surface after multiple battery cells 20 are stacked. The first direction is as follows: Figure 6The X direction is shown in the diagram.

[0121] In this case, since the base film 221 covers the battery cell 21 and has a certain thickness, the circumferential edge of the buffer 222 can extend beyond the circumferential edge of the large surface 210. For example, the extension distance is less than or equal to the thickness of the base film 221. Of course, the extension distance can also be greater than the thickness of the base film 221.

[0122] Of course, in other embodiments, the buffer is located within the coverage area of ​​the orthographic projection of the large surface of the cell in the first direction.

[0123] Understandably, the circumferential edge of the buffer can be set to be located inside the circumferential edge of the large surface of the cell. This not only saves materials, but also allows the space not occupied by the buffer to be used to arrange cooling channels or as a heat dissipation space, so as to provide a better heat dissipation environment for the battery cell.

[0124] For example, the distance between the circumferential edge of the buffer and the circumferential edge of the large surface of the battery cell is less than or equal to 2 mm. In other words, the distance between the circumferential edge of the buffer and the circumferential edge of the large surface should not be too large. If it is too large, the area covered by the buffer on the large surface will be small, which can easily lead to an imbalance in support when stacking battery cells, resulting in the stacked battery cells becoming skewed or collapsing. Therefore, ensuring sufficient contact area between the buffer and other battery cells provides effective support, allowing the stacking pressure to be evenly distributed, which helps improve the flatness of the large surface after multiple battery cells are stacked.

[0125] The distance between the circumferential edge of the buffer and the circumferential edge of the large surface of the battery cell can be selected as 0.5mm, 1mm, 1.5mm or 2.0mm. Of course, other reasonable values ​​can also be selected.

[0126] Alternatively, the circumferential edge of the buffer can be set to be flush with the circumferential edge of the large surface of the battery cell, so that the buffer completely covers the large surface of the battery cell. In this way, when stacking battery cells, the buffer can support and buffer the entire large surface of the upper battery cell, which can increase the contact area.

[0127] Of course, in some other embodiments, the buffer may also cover the large surface of the battery cell and at least part of the side surface of the battery cell. The battery cell has a large surface, an end face, and side surfaces. The large surface is along the thickness direction of the battery cell (e.g., the thickness direction of the cell). Figure 4 The two surfaces on the first direction shown are the largest pair of parallel planes. The end face is the direction in which the battery cell is led out from the tab (as shown in the diagram). Figure 4 As shown in the second direction, the cell has two oppositely arranged end faces, with the tab extending from one of these end faces. The side of the cell is the surface between the two large faces, also known as the narrow side.

[0128] In this way, the buffer not only covers the large surface of the cell, but also covers at least part of the side surface. When stacking multiple cells, the buffer can isolate the corners of adjacent cells, preventing them from bumping or squeezing each other. It can also provide cushioning on the side of the cell.

[0129] This application also provides a battery device 100, which includes a battery cell 20 according to embodiments of this application. Please refer to... Figure 8 , Figure 8 This is an exploded structural diagram of a battery device 100 provided in some embodiments of this application.

[0130] The battery device 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 provides space for the battery cells 20 and can have various structures.

[0131] In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, and together define a receiving space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, with the first portion 11 covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 together define the receiving space; alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0132] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel connections. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0133] This application embodiment also provides an electrical device, including the battery device 100 in the above embodiments, and providing electrical energy through the battery device 100. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0134] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0135] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes: The battery cell (21) has two large surfaces (210) arranged opposite each other in a first direction. Heat shrink film (22) is used to cover the battery cell (21). The heat shrink film (22) includes a base film (221) and a buffer (222). The base film (221) has a first side (2211) and a second side (2212) that are disposed opposite to each other in the first direction and respectively adhere to the two large surfaces (210). At least one layer of the buffer (222) is provided on the outer surface of the first side (2211) and / or the second side (2212).

2. The battery cell according to claim 1, characterized in that, The large surface (210) of the battery cell (21) is located within the coverage area of ​​the orthographic projection of the buffer (222) in the first direction.

3. The battery cell according to claim 1, characterized in that, The buffer (222) is located within the coverage area of ​​the large surface (210) of the cell (21) in the first direction.

4. The battery cell according to claim 3, characterized in that, The distance between the circumferential edge of the buffer (222) and the circumferential edge of the large surface (210) of the battery cell (21) is less than or equal to 2 mm.

5. The battery cell according to claim 1, characterized in that, The buffer (222) covers the large surface (210) of the cell (21) and at least part of the side surface of the cell (21).

6. A heat-shrinkable film, characterized in that, Suitable for battery cells as described in any one of claims 1 to 5, the heat-shrink film comprises: The substrate film (221) has a first side portion (2211) and a second side portion (2212) disposed opposite to each other in a first direction and both used to adhere to the large surface (210) of the battery cell (21). The buffer (222) has at least one layer of the buffer (222) on the outer surface of the first side (2211) and / or the second side (2212).

7. The heat-shrinkable film according to claim 6, characterized in that, The buffer (222) is bonded to the base film (221).

8. The heat-shrinkable film according to claim 6, characterized in that, The buffer (222) is a foam pad, a rubber pad, a buffer film, or a composite heat-insulating buffer pad.

9. The heat-shrinkable film according to claim 6, characterized in that, The battery cell (21) is a soft-pack solid-state battery cell, and the thickness of the buffer (222) is 5μm-30μm.

10. The heat-shrinkable film according to claim 6, characterized in that, The battery cell (21) is a soft-pack liquid battery cell, and the thickness of the buffer (222) is 3mm-5mm.

11. The heat-shrinkable film according to claim 6, characterized in that, The buffer (222) is constructed as a flat plate structure.

12. The heat-shrinkable film according to claim 6, characterized in that, The substrate film (221) is constructed as a bag-shaped structure with one end open in a second direction, which is the tab lead-out direction of the battery cell (21).

13. The heat-shrinkable film according to claim 6, characterized in that, The substrate film (221) is constructed as a cylindrical structure with openings at both ends in a second direction, which is the direction in which the tabs of the battery cell (21) are led out.

14. The heat-shrinkable film according to claim 6, characterized in that, The outer surface of the first side (2211) and / or the second side (2212) is provided with multiple layers of the buffer (222), which are stacked in the first direction.

15. A battery device, characterized in that, The battery device comprises a battery cell as described in any one of claims 1 to 5.

16. An electrical appliance, characterized in that, Includes the battery device as described in claim 15, wherein the battery device is used to provide electrical energy.

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