Battery device and electric equipment

Abstract

The utility model discloses a battery device and electric equipment. The battery device comprises a box body, a battery monomer assembly and a separation assembly, the battery monomer assembly is arranged in the box body, the battery monomer assembly comprises a plurality of battery monomers arranged along a first direction, each battery monomer comprises a shell and an end cover, the end cover is positioned on one side of the shell along a second direction, and the shell is connected with the end cover through a connecting piece. The first direction and the second direction intersect. The separation assembly is arranged between two adjacent battery monomers in the first direction, the separation assembly comprises a buffer layer and a heat insulation layer which are stacked in the first direction, and a stress avoiding space is formed in the separation assembly. And the separation assemblies are at least partially arranged at intervals through the stress avoiding spaces and the connecting pieces of the adjacent battery monomers. According to the technical scheme, the risk of failure of the joint of the shell and the end cover after the single battery is subjected to external force can be reduced, and the risk of thermal runaway of the single battery assembly is reduced.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery device and an electrical appliance. Background Technology

[0002] Batteries are widely used in various electronic devices, such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy airplanes, electric toy ships, power tools, and energy storage systems, etc.

[0003] However, when a battery cell is subjected to vibration or impact, the connection area between the end cap and the casing is prone to cracking, increasing the risk of thermal runaway in the battery device. Therefore, improvements to the aforementioned structure are necessary. Utility Model Content

[0004] In view of the above problems, this application provides a battery device and an electrical device that can reduce the risk of battery cells cracking and failing after being subjected to external forces, and reduce the risk of thermal runaway of battery cell assemblies.

[0005] In a first aspect, this application provides a battery device, including a housing, a battery cell assembly, and a separator assembly. The battery cell assembly is disposed within the housing and includes multiple battery cells arranged along a first direction. Each battery cell includes a housing and an end cap. The end cap is located on one side of the housing along a second direction, and the housing and end cap are connected by a connector. The first and second directions intersect. The separator assembly is disposed between two adjacent battery cells along the first direction and includes a buffer layer and a heat insulation layer stacked along the first direction, forming a stress-avoidance space. The separator assembly is at least partially spaced from the adjacent battery cells by the stress-avoidance space and the connector. In the second direction, the connector protrudes from the heat insulation layer towards the edge of the end cap to form the stress-avoidance space.

[0006] In the technical solution of this application embodiment, the housing provides a stable installation space for the battery cells, reducing the impact of external impurities and moisture on the battery cells. The partition component between two battery cells reduces heat transfer between them, lowering the risk of battery cell failure due to thermal runaway. It also reduces stress transfer between battery cells, lowering the risk of deformation and cracking. Specifically, by forming a stress-avoidance space, deformation space is provided for battery cell expansion or external pressure, preventing stress from directly acting on the connection area between the end cap and the housing. At least a portion of the connector is spaced apart from the stress-avoidance space, meaning the connection position is precisely designed in a low-stress area, reducing the risk of cracking. Therefore, the above structure effectively reduces the risk of thermal runaway of battery cells and improves the operational stability of the battery device. Furthermore, by changing the placement of the insulation layer to form the stress-avoidance space, the structure is simple and easy to install.

[0007] In some embodiments, the orthographic projection of the connector onto the battery cell's casing falls entirely within the projection range of the stress relief space onto the casing. This structure further reduces the stress at the battery cell's connection points, lowers the risk of cracking of the battery cell's casing and end caps, and improves the operational stability of the battery cell.

[0008] In some embodiments, in the second direction, the edge of the heat insulation layer near the end cap protrudes beyond the corresponding edge of the buffer layer. This structure, by positioning the heat insulation layer higher than the buffer layer, reduces stress transmission from the buffer layer to the edge of the heat insulation layer, further reducing stress transmission to the connection between the casing and the end cap, and improving the structural stability of the battery cell.

[0009] In some embodiments, the height H1 of the heat insulation layer protruding from the buffer layer satisfies: 6mm ≤ H1 ≤ 15mm. In the above structure, by setting the protrusion height of the edge of the heat insulation layer within a suitable range, the stress transmission is reduced while ensuring the buffering effect of the buffer layer, thereby improving the structural stability of the battery cell.

[0010] In some embodiments, the buffer layer has a relief groove on the side surface facing the connector. In the above structure, by providing a groove on the buffer layer, stress transmission is reduced, and the stability of the battery cell structure is improved.

[0011] In some embodiments, the heat insulation buffer pad further includes a first adhesive layer and a second adhesive layer. The first adhesive layer is disposed on the side of the heat insulation layer opposite to the buffer layer and is bonded to the adjacent battery cell. The second adhesive layer is disposed on the side of the buffer layer opposite to the heat insulation layer and is bonded to the adjacent battery cell. In the above structure, the first adhesive layer provides a stable connection between the heat insulation layer and the battery cell, and the second adhesive layer provides a stable connection between the buffer layer and the battery cell, thereby improving the connection stability between the separator assembly and the battery cell.

[0012] In some embodiments, the end cap and the housing are welded together, and the connector is an annular weld formed at the joint between the end cap and the housing. In the above structure, the welding method can improve the connection strength between the end cap and the housing, and the annular weld reduces welding blind spots and stress concentration points, thereby improving the structural stability of the connection between the end cap and the housing.

[0013] In some embodiments, the top surface of the end cap is flush with the end face of the housing. In the above structure, the flush butt joint allows for a smoother transition of the stress-bearing cross-section between the end cap and the housing at the weld, avoiding the abrupt changes in cross-section caused by a stepped structure. This structure effectively reduces stress concentration at the weld root. The stress avoidance space prevents external stress peaks from directly acting on the weld area, and the flush butt joint structure itself has superior fatigue resistance. Together, these factors reduce the risk of weld cracking under long-term vibration and impact loads.

[0014] In some embodiments, the thickness W1 of the buffer layer satisfies: 2mm ≤ W1 ≤ 3mm. In the above structure, setting the thickness of the buffer layer within a suitable range ensures that the buffering effect reduces stress transmission while reducing the space occupied by the buffer layer.

[0015] In some embodiments, the thickness W2 of the insulation layer satisfies: 1.5mm ≤ W2 ≤ 3mm. In the above structure, setting the thickness of the insulation layer within a suitable range ensures the insulation effect reduces heat transfer while minimizing the space occupied by the insulation layer.

[0016] Secondly, this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0017] 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

[0018] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0019] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0020] Figure 2 Explosion-proof diagrams of battery devices provided in some embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0022] Figure 4 This is a partial structural schematic diagram of a battery device provided in some embodiments of this application;

[0023] Figure 5 for Figure 4 A magnified structural diagram of part A in the middle;

[0024] Figure 6This is a partial structural schematic diagram of a battery device provided in other embodiments of this application;

[0025] Figure 7 This is a partial structural schematic diagram of a battery device provided in other embodiments of this application;

[0026] Figure 8 This is a schematic diagram of the structure of the heat insulation cushioning pad provided in some embodiments of this application;

[0027] Figure 9 This is a partial structural schematic diagram of a battery device provided in other embodiments of this application;

[0028] Figure 10 This is a partial structural schematic diagram of a battery device provided for other embodiments of this application.

[0029] Detailed Explanation of Reference Numerals

[0030] 1. Vehicle; 2. Battery assembly; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 6. Battery cell; 10. Electrode assembly; 20. Housing; 30. End cap; 40. Shell; 50. Electrode terminal; 60. Connector; 70. Stress relief space; 7. Battery cell assembly; 8. Separator assembly; 801. Buffer layer; 802. Heat insulation layer; 803. Heat insulation buffer pad; 804. First adhesive layer; 805. Second adhesive layer; 806. Relief groove; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] In this application, "multiple" means two or more (including two).

[0040] In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0041] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0042] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0043] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0044] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0045] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0046] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0047] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0048] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0049] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0050] Liquid electrolytes include electrolyte salts and solvents.

[0051] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge and fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0052] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0053] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0054] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0055] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0056] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0057] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0058] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0059] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap covering the opening. Optionally, the end cap has an injection hole for injecting electrolyte into the casing. The casing may have one or more openings. The end cap may also be provided with one or more.

[0060] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0061] A battery cell includes a casing, which typically consists of a housing and end caps. These are welded together, for example, using laser welding, to form a circumferential weld around the end cap for sealing. When heat insulation pads or buffer pads are directly placed on the sides of the battery cell, if the battery deforms due to internal gas generation or is subjected to external forces such as compression or vibration, the casing (especially the sidewalls) will directly transfer stress to the connection between the end cap and the housing. Since the weld area is a structurally weak point, this direct compression or tension will cause stress concentration at the weld and subject it to significant vibration stress. This condition easily leads to weld fatigue damage or even cracking, resulting in failure modes such as leakage and short circuits. This not only reduces the pass rate of battery modules in vibration tests but also seriously affects the long-term reliability and safety of the product.

[0062] In view of this, embodiments of this application provide a battery device in which a housing provides a stable mounting space for individual battery cells, reducing the impact of external impurities and moisture on the battery cells. The partition component between two battery cells reduces heat transfer between them, lowering the risk of individual cell failure due to thermal runaway. It also reduces stress transfer between cells, decreasing the risk of deformation and cracking. Specifically, by forming a stress-avoidance space, deformation space is provided for battery cell expansion or external pressure, preventing stress from directly acting on the connection area between the end cap and the housing. At least a portion of the connector is spaced apart from the stress-avoidance space, meaning the connection position is precisely designed in a low-stress area, reducing the risk of cracking. Therefore, the above structure effectively reduces the risk of thermal runaway of individual battery cells and improves the operational stability of the battery device.

[0063] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0064] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0065] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0066] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0067] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0068] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0069] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0070] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0071] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0072] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0073] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0074] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0075] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0076] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0077] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0078] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0079] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and battery cells 6, with the battery cells 6 housed within the housing 5. The battery cell 6 can be the smallest unit that makes up a battery.

[0080] The housing 5 is used to house the battery cell 6, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a receiving space for housing the battery cell 6. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with a receiving space; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with a receiving space. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.

[0081] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0082] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0083] In the battery device 2, there can be one or more battery cells 6. If there are multiple battery cells 6, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 6 are connected in both series and parallel.

[0084] Multiple battery cells 6 can be directly connected in series, parallel, or in a mixed manner, and then the whole composed of multiple battery cells 6 can be housed in the housing 5; of course, multiple battery cells 6 can also be connected in series, parallel, or in a mixed manner to form a battery module, and multiple battery modules can then be connected in series, parallel, or in a mixed manner to form a whole, and housed in the housing 5.

[0085] Please refer to the reference. Figures 2 to 5 , Figure 2 This is an exploded schematic diagram of a battery device provided in some embodiments of this application. Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application. Figure 4 This is a partial structural diagram of a battery device provided in some embodiments of this application. Figure 5 for Figure 4 A magnified structural diagram of part A in the middle.

[0086] As shown in the figure, an embodiment of this application provides a battery device 2, including a housing 5, multiple battery cell assemblies, and a separator assembly 8. Battery cell assemblies 6 are disposed within the housing 5, and each battery cell 6 assembly includes multiple battery cells 6 arranged along a first direction X. Each battery cell 6 includes a housing 40 and an end cap 30. The end cap 30 is located on one side of the housing 40 along a second direction Y, and the housing 40 and the end cap 30 are connected by a connector 60. The first direction X and the second direction Y intersect. The separator assembly 8 is disposed between two adjacent battery cells 6 along the first direction X. The separator assembly 8 includes a buffer layer 801 and a heat insulation layer 802 stacked along the first direction X, and the separator assembly 8 forms a stress relief space 70. The separator assembly 8 is at least partially spaced from the adjacent battery cells 6 by the stress relief space 70 and the connector 60. In the second direction Y, the connector 60 protrudes from the heat insulation layer 802 toward the edge of the end cap 30 to form the stress relief space 70.

[0087] Optionally, the connector 60 can be a weld or an adhesive. For example, the weld is a closed weld bead formed by circumferential welding along the periphery of the end cap 30 after the cylindrical or cup-shaped shell 40 is butt-welded to the plate-shaped end cap 30 in the second direction Y using high-energy beam welding processes such as laser welding or ultrasonic welding. This weld is located at the edge region where the end cap 30 connects to the shell 40 and is a core element for achieving the internal airtightness of the battery cell 6 and preventing electrolyte leakage. Due to the heat-affected zone effect during welding, the grain structure and mechanical properties of the weld and its adjacent areas differ from the base material, making this area a mechanically weak point in the structural strength of the battery cell 6. Under long-term cycling, external vibration, or compression, especially when the shell 40 expands due to internal gas generation, stress easily concentrates in this area, leading to fatigue microcracks that may propagate into through cracks, resulting in sealing failure.

[0088] The stress relief space 70 refers to the physical gap between the sidewall surface of the battery cell 6 and the surface of the heat insulation layer 802 of the separator assembly 8. Optionally, this area can be actively formed by structurally designing the battery cell 6 to have a larger outline dimension than the heat insulation layer 802. Specifically, the edge of the battery cell 6, that is, the area near the end cap 30 and the weld, protrudes outward, extending beyond the corresponding edge of the heat insulation layer 802.

[0089] When the battery cell 6 swells due to internal gas generation, or when the battery assembly 2 is subjected to external compression, the sidewall of the battery cell 6 tends to deform outward. The stress relief space 70 provides a pre-set buffer space for this deformation, allowing it to occur slightly, thus preventing the sidewall of the battery cell 6 from making rigid contact or hard collision with the rigid heat insulation layer 802.

[0090] Without the stress relief space 70, the deformation of the battery cell 6 would be directly and rapidly transmitted to the entire structure through the heat insulation layer 802, ultimately concentrating the stress in the weakest weld area. However, in the structure described in this application, the stress transmission path is altered or prolonged due to the presence of the stress relief space 70. The deformation of the battery cell 6 is first released within this cavity, significantly reducing the peak stress ultimately transmitted to the end cap 30 and the weld area.

[0091] In the technical solution of this application embodiment, the housing 5 provides a stable installation space for the battery cells 6, reducing the impact of external impurities and moisture on the battery cells 6. The partition component 8 between two battery cells 6 reduces heat transfer between them, lowering the risk of thermal runaway and battery cell 6 failure. It also reduces stress transfer between the battery cells 6, lowering the risk of deformation and cracking. Specifically, by forming a stress-avoidance space 70, deformation space is provided for the battery cells 6 to expand or be subjected to external pressure, preventing stress from directly acting on the connection area between the end cap 30 and the housing 40. At least a portion of the connector 60 is spaced apart from the stress-avoidance space 70, meaning the connection position is precisely designed in a low-stress area, reducing the risk of cracking. Furthermore, the connector 60 protrudes from the edge of the end cap 30 into the heat insulation layer 802, reducing the stress on the connector 60 of the battery cells 6, lowering the risk of cracking between the housing 40 and the end cap 30, and improving the operational stability of the battery cells 6. Therefore, the above structure can effectively reduce the risk of thermal runaway of battery cell 6 and improve the operational stability of battery device 2.

[0092] In some embodiments of this application, the stress avoidance space includes a first region, which is formed by the end cap 30 protruding from the heat insulation layer 802. With the above structure, when the battery cell 6 is subjected to vibration or impact, the separator 8 can prevent the impact and vibration from acting on the end cap 30, reduce the direct impact on the connector 60 provided between the end cap 30 and the housing 40, and improve the stability of the connection between the housing 40 and the end cap 30.

[0093] In some embodiments of this application, the stress avoidance space includes a second region, which is formed by the housing 40 protruding from the heat insulation layer 802. With the above structure, when the battery cell 6 is subjected to vibration or impact, the separating component 8 can absorb a certain amount of vibration and reduce the direct transmission of the aforementioned pressure to the area where the housing 40 and the end cap 30 are connected, further reducing the impact on the end cap 30 and the connection area of ​​the housing 40, and improving the structural stability of the battery cell 6. In some embodiments of this application, the stress avoidance space 70 is formed by the edge of the battery cell 6 near the connector 60 protruding from the heat insulation layer 802.

[0094] During cyclic use, the battery may experience slight bulging due to increased internal pressure caused by gas evolution. This bulge provides a pre-defined and controllable deformation space for the expansion of the battery cell 6 along the second direction Y. The casing 40 can undergo slight deformation within this space, thereby releasing some stress and preventing stress from being completely transmitted to the end cap 30 through the casing 40.

[0095] Without introducing complex moving parts or special flexible materials, simply changing the size and installation position of the insulation layer 802 creates a stress-avoidance space 70. This subtractive design, or positional offset design, requires minimal changes to existing production processes, only needing control during the design and assembly stages. It is very easy to implement and does not increase additional parts costs, making it highly industrially practical. Furthermore, the absence of moving parts enhances its reliability.

[0096] Since the weakest and most sensitive connection area of ​​the battery cell 6 is usually located at its edge (i.e., the protruding area), this design ensures that this area faces an "empty" buffer zone, rather than a rigid heat insulation layer 802. When the module is subjected to external pressure, the pressure is first borne by the more robust sidewall of the battery casing 40, or absorbed by the deformation of the buffer layer 801, thus preventing the vulnerable weld area from directly bearing huge impacts or pressures, achieving precise protection for critical parts.

[0097] like Figure 7 As shown, in some embodiments of this application, the orthographic projection of the connector 60 onto the casing 20 of the battery cell 6 falls entirely within the stress relief space 70. For example, the orthographic projection of the connector 60 in the second direction Y falls entirely within the stress relief space 70.

[0098] For example, viewed from the second direction Y, the outline of the battery cell 6 is a rectangle, with its top edge (i.e., the protruding portion) forming an upper boundary in the projection. The projection of the stress avoidance space 70 is a section of the top of this rectangle.

[0099] In rigorous tests such as vibration, impact, and compression, the magnitude and direction of stress are complex and variable. The "complete fall-in" design ensures that the connector 60 is protected by the stress avoidance space 70 under all possible angles and operating conditions, thereby improving the confidence and pass rate of the battery cell assembly 7 in passing the most stringent safety tests. When the battery cell 6 bulges, its deformation is most pronounced in the edge area of ​​the end cover 30. Requiring the connector 60 to "completely fall into" the avoidance area provides a uniform buffer space for the entire circumferential deformation of the end cover 30 edge, ensuring that the tensile stress on the connector 60 is effectively released in the event of bulging, further reducing the risk of the connector 60 tearing due to bulging.

[0100] The above structure further reduces the stress on the connector 60 of the battery cell 6, reduces the risk of cracking of the housing 40 and end cap 30 of the battery cell 6, and improves the operational stability of the battery cell 6.

[0101] like Figure 7 As shown, in some embodiments of this application, in the second direction Y, the edge of the heat insulation layer 802 near the end cap 30 protrudes beyond the corresponding edge of the buffer layer 801. For example, the edge of the heat insulation layer 802 in the third direction Z protrudes beyond the corresponding edge of the buffer layer 801 in the third direction Z, where the third direction Z is perpendicular to both the first direction X and the second direction Y.

[0102] The buffer layer 801 is typically made of a soft, compressible material, such as foam, silicone, or rubber. Its main function is to absorb mechanical energy and cushion impacts through its own deformation. The heat insulation layer 802 is typically made of a more rigid, less deformable material, such as mica sheet, hard ceramic fiber board, or a composite layer of metal foil and heat insulation material. Its main function is to block heat transfer. The rigidity of the heat insulation layer 802 is greater than that of the buffer layer 801. During assembly, one edge of the heat insulation layer 802 in the third direction Z protrudes upwards more than the corresponding edge of the buffer layer 801. This forms a stepped structure, in which the more rigid heat insulation layer 802 is the part that first contacts the battery cell 6.

[0103] For example, the buffer layer 801 has a height of 17mm, and the heat insulation layer 802 has a height of 20mm. During assembly, instead of aligning the two, the heat insulation layer 802 protrudes 2mm-3mm more than the buffer layer 801 in the third direction (Z). Thus, from the perspective of the battery cell 6, the edge of this 2mm protruding rigid heat insulation layer 802 is the first point of contact, followed by the buffer layer 801.

[0104] Because the heat insulation layer 802 protrudes further, when the battery cell 6 expands or is subjected to external pressure, the edge of the rigid heat insulation layer 802 will contact the battery cell 6 casing 40 before the soft buffer layer 801. This necessary, localized contact will first disperse and conduct some of the stress through the more rigid heat insulation layer 802, thereby changing the force transmission path.

[0105] Conversely, if the buffer layer 801 protrudes more, the soft buffer material will immediately undergo large deformation, directly and completely transferring the stress to the insulation layer 802 on its back, ultimately directing all the stress towards the weld of the end cap 30. This design, however, diverts some of the stress through the preferential contact of the rigid insulation layer 802.

[0106] The above structure, by setting the heat insulation layer 802 higher than the buffer layer 801, reduces the stress transmission from the buffer layer 801 to the edge of the heat insulation layer 802, further reduces the stress transmission to the weld, and improves the structural stability of the battery cell 6.

[0107] like Figure 8 As shown, in some embodiments of this application, the separator 8 includes a plurality of independent heat insulation buffer pads 803, each heat insulation buffer pad 803 including a buffer layer 801 and a heat insulation layer 802 stacked together, and each heat insulation buffer pad 803 is provided for a pair of adjacent battery cells 6.

[0108] The independent heat insulation buffer pads 803 refer to each heat insulation buffer pad 803 being a pre-fabricated independent functional unit containing a buffer layer 801 and a heat insulation layer 802. These pads are physically separate and not rigidly connected to each other. Each independent heat insulation buffer pad 803 is precisely positioned between a pair of adjacent battery cells 6. This arrangement forms a corresponding configuration of one independent pad for each gap between battery cells 6.

[0109] Suppose that a battery cell assembly 7 consists of 10 battery cells 6. Then, between another battery cell assembly 7 adjacent to it, 10 independent heat insulation buffer pads 803 need to be installed, each heat insulation buffer pad 803 precisely aligned with the gap between the two battery cells 6.

[0110] If a continuous, monolithic thermal insulation panel is ignited or damaged, its insulation performance will fail over a large area. In contrast, the individual gasket design isolates the risk of thermal runaway propagation within the area corresponding to a single battery cell 6. If a battery cell 6 experiences thermal runaway, the high-temperature ejected material primarily affects the individual gasket directly opposite it. Even if this gasket is burned out, the gaskets on either side remain intact, continuing to effectively insulate heat and preventing the chain propagation of thermal runaway along the battery cell assembly 7 arrangement direction (first direction X).

[0111] When a battery cell 6 bulges, its expansion force mainly acts on the independent gasket directly opposite it. The buffer layer 801 of this gasket can undergo localized deformation to absorb energy, without diffusing stress through a rigid integral plate to the adjacent, unbulged battery cell 6 area, thus minimizing the range of mechanical stress influence.

[0112] In addition, individual gaskets are easier to install and replace. During assembly, the position of the gaskets can be flexibly adjusted, or gaskets with different performance characteristics can be combined. If a gasket is damaged during testing or use, it can be replaced individually without replacing the entire large component, reducing maintenance costs.

[0113] In the above structure, by setting an independent heat insulation buffer pad 803, the stress and heat transfer between adjacent battery cells 6 are reduced, thereby improving the overall operational stability of the battery device 2.

[0114] like Figure 7 as well as Figure 8 As shown, in some embodiments of this application, the edge of the heat insulation layer 802 near the end cap 30 protrudes beyond the corresponding edge of the buffer layer 801. This structure, by setting the heat insulation layer 802 higher than the buffer layer 801, reduces the stress transmission from the buffer layer 801 to the edge of the heat insulation layer 802, further reducing stress transmission to the connection between the housing 40 and the end cap 30, and improving the structural stability of the battery cell 6.

[0115] In some embodiments of this application, the height H1 of the heat insulation layer 802 protruding from the buffer layer 801 satisfies: 6mm≤H1≤15mm.

[0116] For example, assuming the protrusion is too small (e.g., <6mm), when the battery cell 6 expands or is compressed, the soft buffer layer 801 may quickly compress and "submerge" this small protrusion height, causing the rigid heat insulation layer 802 to be unable to preferentially contact or effectively divert stress, rendering the design ineffective. A 6mm protrusion ensures that the heat insulation layer 802 provides effective rigid resistance to the aforementioned forces. Sufficient protrusion ensures that the heat insulation layer 802 can prevent the buffer layer 801 from being directly scratched by the outside environment, maintaining its structural integrity.

[0117] Excessive protrusion (e.g., >15mm) unnecessarily increases the overall dimensions of the separator assembly 8, thus occupying valuable space within the battery module and hindering the improvement of system energy density. An excessively long cantilever (protruding heat insulation layer 802) will experience a large bending moment at its root upon impact, posing a risk of breakage. The 15mm upper limit ensures that the heat insulation layer 802, while fulfilling its current shunting function, possesses sufficient structural strength and reliability. Battery deformation can sometimes be significant, requiring the buffer layer 801 to fully utilize its energy absorption function. If the heat insulation layer 802 protrudes excessively, it may excessively suppress the compression stroke of the buffer layer 801, preventing it from effectively absorbing energy at critical moments.

[0118] By precisely controlling H1 within the range of 6-15mm, the stress diversion and protection functions of the heat insulation layer 802 and the energy absorption and buffering functions of the buffer layer 801 achieve optimal synergy. This avoids functional failure due to insufficient protrusion and reduces space waste and structural risks caused by excessive protrusion. Under this optimized balance, the stress transmitted to the weld area of ​​the end cap 30 of the battery cell 6 is minimized, thereby improving the structural stability of the battery cell 6 under harsh conditions such as vibration and extrusion.

[0119] In the above structure, by setting the protrusion height of the edge of the heat insulation layer 802 within a suitable range, the stress transmission is reduced while ensuring the buffering effect of the buffer layer 801, thereby improving the structural stability of the battery cell 6.

[0120] like Figure 9 As shown, in some embodiments of this application, the buffer layer 801 has a relief groove 806 on the side surface facing the connector 60. By providing a groove on the buffer layer, stress transmission is reduced, and the stability of the battery cell 6 structure is improved. At the same time, the above structure is easy to manufacture, improves manufacturing efficiency, and reduces manufacturing costs.

[0121] like Figure 10 As shown, in some embodiments of this application, the heat insulation buffer pad 803 further includes a first adhesive layer 804 and a second adhesive layer 805. The first adhesive layer 804 is disposed on the side of the heat insulation layer 802 away from the buffer layer 801 and is bonded to the adjacent battery cell 6. The second adhesive layer 805 is disposed on the side of the buffer layer 801 away from the heat insulation layer 802 and is bonded to the adjacent battery cell 6. The first adhesive layer 804 is an adhesive, such as double-sided tape, hot melt adhesive, pressure-sensitive adhesive, etc., which is coated or attached to the outer surface of the heat insulation layer 802, that is, the side of the heat insulation layer 802 away from the buffer layer 801. Its functional surface faces and is bonded to the housing 40 of a battery cell 6.

[0122] The second adhesive layer 805 is also an adhesive layer, which is disposed on the outer surface of the buffer layer 801, that is, the side of the buffer layer 801 that faces away from the heat insulation layer 802. Its functional surface faces and is bonded to the housing 40 of the adjacent battery cell 6.

[0123] An independent heat-insulating buffer pad 803 is firmly "clamped" between two adjacent battery cells 6 by adhesive layers on both sides. The buffer layer 801 and the heat-insulating layer 802 are sandwiched in the middle as the core functional layers, while the adhesive layers on both sides are responsible for achieving mechanical connection.

[0124] For example, a first adhesive layer 804 can be provided on the sidewall of each battery cell 6 of the first battery cell assembly 7 to connect one side of the heat insulation buffer pad 803, and then a second adhesive layer 805 can be provided on the side surface of the heat insulation buffer pad 803 opposite to the first adhesive layer 804. Finally, the second battery cell assembly 7 is bonded and positioned to the second adhesive layer 805.

[0125] The adhesive layer provides uniform adhesion across the entire contact surface, firmly bonding the heat insulation buffer pad 803 to the battery cell 6 housing 40 as a whole. This reduces potential micro-movements, collisions, and abnormal noises between the pad and the battery cell 6 during vehicle vibration. Compared to simple "interference fit" or "slot fixing," bonding more effectively suppresses relative displacement caused by differences in the thermal expansion coefficients of different materials, eliminating the potential for functional degradation due to long-term wear.

[0126] In the above structure, the heat insulation layer 802 is stably connected to the battery cell 6 by setting the first adhesive layer 804, and the buffer layer 801 is stably connected to the battery cell 6 by setting the second adhesive layer 805, thereby improving the connection stability between the separator assembly 8 and the battery cell 6.

[0127] In some embodiments of this application, the end cap 30 and the housing 40 are welded together, and the connector 60 is an annular weld formed at the junction of the end cap 30 and the housing 40. In the above structure, the welding method can improve the connection strength between the end cap 30 and the housing 40, and the annular weld reduces welding blind spots and stress concentration points, thereby improving the structural stability of the connection between the end cap 30 and the housing 40. In some embodiments, the top surface of the end cap 30 is flush with the end surface of the housing 40.

[0128] In the above structure, the flush butt joint allows for a smoother transition of the stress-bearing cross-section between the end cap 30 and the shell 40 at the weld, avoiding abrupt changes in cross-section caused by a stepped structure. This structure effectively reduces stress concentration at the weld root. The stress avoidance space 70 prevents external stress peaks from directly acting on the weld area, and the flush butt joint structure itself has superior fatigue resistance. Together, these two features reduce the risk of weld cracking under long-term vibration and impact loads.

[0129] In some embodiments of this application, the thickness W1 of the buffer layer 801 satisfies: 2mm≤W1≤3mm.

[0130] For example, a buffer layer 801 with a thickness of less than 2 mm has very limited compressible deformation space. When the battery cell 6 bulges or the module is squeezed, the excessively thin buffer layer 801 will be quickly compressed into a solid state, unable to absorb energy through further deformation, thus losing its buffering effect and resulting in rigid impact. A certain thickness is the basis for ensuring stable and predictable mechanical properties of porous / elastic materials such as foam and silicone. Materials that are too thin have large performance fluctuations and are prone to permanent deformation (creep relaxation) after long-term pressure, leading to preload failure.

[0131] Thicknesses exceeding 3mm may exhibit diminishing returns. That is, increasing thickness no longer improves cushioning performance, but linearly increases space requirements and material costs. A thickness of 3mm is considered the critical point for achieving effective cushioning at a cost-effectiveness ratio with commonly used cushioning materials (such as foam of a certain density).

[0132] The range of 2mm ≤ W1 ≤ 3mm is not a broad, conventional choice, but a precise optimization range. This allows the buffer layer 801 to provide reliable and sufficient buffering performance within a limited space. It avoids functional failure due to excessive thinness and space waste due to excessive thickness. This enables the battery device 2 to maintain structural integrity during mechanical shock testing while achieving the highest possible energy density.

[0133] In the above structure, the thickness of the buffer layer 801 is set within a suitable range to ensure that the buffering effect reduces stress transmission while reducing the space occupied by the buffer layer 801.

[0134] In some embodiments of this application, the thickness W2 of the insulation layer 802 satisfies: 1.5mm ≤ W2 ≤ 3mm.

[0135] The thermal insulation effect of the insulation layer 802 is positively correlated with its thickness. Insufficient thickness (e.g., <1.5mm) results in too low thermal resistance. In the event of thermal runaway in an adjacent battery cell 6, high temperatures and flames may rapidly penetrate the insulation layer 802, failing to play its crucial role in delaying or preventing heat spread and leading to systemic thermal failure. An excessively thin insulation layer 802 (such as ceramic fiber paper or thin-layer aerogel) has poor mechanical strength and is prone to tearing and damage during assembly or vibration, leading to localized thermal insulation failure. A thickness of 1.5mm ensures it possesses the basic strength and durability required for a structural component.

[0136] Similar to the buffer layer 801, the thickness of the heat insulation layer 802 directly increases the total width of the battery cell assembly 7. Keeping W2 below 3mm while meeting thermal safety requirements is crucial for improving the overall volumetric energy density of the battery system. For most heat insulation materials, the increase in thermal resistance is not linearly proportional to thickness. Once the thickness exceeds a certain value (such as 3mm), the improvement in heat insulation performance for each additional 1mm is very limited, while the space occupied and material cost increase. Therefore, 3mm is a critical thickness with extremely high cost-effectiveness.

[0137] The range of 1.5mm ≤ W2 ≤ 3mm represents the optimal balance between thermal insulation performance and space utilization. This ensures that the insulation layer 802 provides reliable and compliant thermal runaway protection within an extremely limited space. This allows the battery device 2 to maximize energy density while passing stringent thermal diffusion tests.

[0138] In the above structure, the thickness of the insulation layer 802 is set within a suitable range to ensure the insulation effect, reduce heat transfer, and reduce the space occupied by the insulation layer 802.

[0139] In some alternative embodiments, the battery device 2 includes a housing, battery cell assemblies 7, and a separator assembly 8. Battery cell assemblies 6 are disposed within the housing 5, and each battery cell 6 assembly includes multiple battery cells 6 arranged along a first direction X. Each battery cell 6 includes a housing 40 and an end cap 30, which are connected by a connector 60. The separator assembly 8 is disposed between two adjacent battery cells 6 along the first direction X. The separator assembly 8 includes a buffer layer 801 and a heat insulation layer 802 stacked along the first direction X, and forms a stress relief space 70. The separator assembly 8 is at least partially spaced from the adjacent battery cell 6 by the stress relief space 70 and the connector 60. The stress relief space 70 is formed by the edge of the connector 60 protruding from the heat insulation layer 802 near the end cap 30. The orthographic projection of the connector 60 onto the housing 20 of the battery cell 6 falls entirely within the projection range of the stress relief space 70 onto the housing 20. The edge of the heat insulation layer 802 near the end cap 30 protrudes from the corresponding edge of the buffer layer 801. The heat insulation buffer pad 803 also includes a first adhesive layer 804 and a second adhesive layer 805. The first adhesive layer 804 is disposed on the side of the heat insulation layer 802 away from the buffer layer 801 and is bonded to the adjacent battery cell 6. The second adhesive layer 805 is disposed on the side of the buffer layer 801 away from the heat insulation layer 802 and is bonded to the adjacent battery cell 6.

[0140] An embodiment of this application also provides an electrical device, which includes the battery device 2 in the above embodiments, the battery device 2 being used to provide electrical energy. The electrical device can also achieve the technical effects of the above embodiments, and will not be described in detail here.

[0141] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 device, characterized in that, include: Box; A battery cell assembly is disposed within the housing. The battery cell assembly includes a plurality of battery cells arranged along a first direction. Each battery cell includes a housing and an end cap. The end cap is located on one side of the housing along a second direction, and the housing and the end cap are connected by a connector. The first direction and the second direction intersect. A separator assembly is disposed between two adjacent battery cells along a first direction. The separator assembly includes a buffer layer and a heat insulation layer stacked along the first direction, and the separator assembly forms a stress relief space. The separation assembly is at least partially spaced apart from the stress relief space and the connector of the adjacent battery cell. In the second direction, the connector protrudes from the heat insulation layer toward the edge of the end cap to form the stress relief space.

2. The battery device according to claim 1, characterized in that, The orthographic projection of the connector on the outer casing of the battery cell falls completely within the projection range of the stress relief space on the outer casing.

3. The battery device according to claim 1, characterized in that, In the second direction, the edge of the heat insulation layer near the end cap protrudes beyond the corresponding edge of the buffer layer.

4. The battery device according to claim 3, characterized in that, The height H1 by which the heat insulation layer protrudes from the buffer layer satisfies: 6mm ≤ H1 ≤ 15mm.

5. The battery device according to claim 1, characterized in that, The buffer layer has a relief groove on the side surface facing the connector.

6. The battery device according to any one of claims 1-5, characterized in that, The separation component also includes: The first adhesive layer is disposed on the side of the heat insulation layer away from the buffer layer and is bonded to the adjacent battery cell; The second adhesive layer is disposed on the side of the buffer layer away from the heat insulation layer and is bonded to the adjacent battery cell.

7. The battery device according to any one of claims 1-5, characterized in that, The end cap and the housing are welded together, and the connecting member is an annular weld formed at the junction of the end cap and the housing.

8. The battery device according to claim 7, characterized in that, The top surface of the end cap is flush with the end surface of the housing.

9. The battery device according to any one of claims 1-5, characterized in that, The thickness W1 of the buffer layer satisfies: 2mm≤W1≤3mm.

10. The battery device according to any one of claims 1-5, characterized in that, The thickness W2 of the insulation layer satisfies: 1.5mm≤W2≤3mm.

11. An electrical appliance, characterized in that, The electrical equipment includes a battery device as described in any one of claims 1-10, the battery device being used to provide electrical energy.

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