CN121663128A - Battery pack and electric equipment - Google Patents

Abstract

The application relates to a battery pack and electric equipment, and relates to the technical field of batteries. The battery cell is provided with a pole piece and a pole lug connected to the pole piece, and the bus bar is connected to one end of the pole lug far away from the pole piece. The first adhesive layer is encapsulated between the bus bar and the pole piece and coats the connection part of the pole piece and the pole lug, the second adhesive layer is encapsulated between the bus bar and the first adhesive layer and coats the connection part of the bus bar and the pole lug, wherein the elastic modulus of the first adhesive layer is a, the elastic modulus of the second adhesive layer is b, and a is smaller than b. Through the gradient distribution of the elastic modulus, the first adhesive layer forms flexible buffer in the tab area to adapt to the expansion deformation of the pole piece, and the second adhesive layer forms rigid support to absorb impact load, so that the structural strength and reliability of the tab connection part are improved to a certain extent, and the safety performance of the battery pack under the conditions of falling and vibration is improved.

Description

Battery pack and electric equipment

Technical Field

The application relates to the technical field of batteries, in particular to a battery pack and electric equipment.

Background

At present, an electric vertical take-off and landing (eVTOL) aircraft operates in a high-altitude complex environment, and more stringent requirements are put forward on the mechanical strength and safety performance of a power battery module, and particularly in a drop test, the module still has reliable protective performance when impacted.

However, the protection design of the existing soft package battery module at the electrode lead-out part still has outstanding problems. Because the electrode lead-out area is generally integrated with different structural components such as a bus bar, a tab and the like, the electrode lead-out area can meet the protection buffer requirement in the drop test process, but the tab is easily damaged in the use process of the battery, so that the performance and the safety of the battery are affected.

Disclosure of Invention

The embodiment of the application provides a battery pack and electric equipment so as to at least partially solve the technical problems.

In order to achieve the above object, according to a first aspect of the present application, there is provided a battery pack comprising:

The battery cell comprises a pole piece and a pole lug, wherein the pole lug is connected to the pole piece;

The busbar is connected to one end of the tab, which is far away from the pole piece;

The first adhesive layer is encapsulated between the busbar and the pole piece, and coats the connecting part of the pole piece and the pole lug;

A second adhesive layer encapsulated between the bus bar and the first adhesive layer and covering the connection part of the bus bar and the tab, wherein,

The elastic modulus of the first adhesive layer is a, and the elastic modulus of the second adhesive layer is b, wherein a is smaller than b.

Through the technical scheme, the gradient buffer structure is formed by arranging the two layers of adhesive layers with different elastic moduli between the pole piece and the bus bar, wherein the elastic modulus of the first adhesive layer is smaller, the gradient buffer structure has a flexible buffer effect, the connection part of the pole lug and the pole piece can be kept stable and not easy to break due to follow-up deformation in the expansion or circulation process of the pole piece, the elastic modulus of the second adhesive layer is larger, the hardness is higher, the rigid support can be provided when falling or mechanical impact is carried out, and the connection part of the bus bar and the pole lug is prevented from breaking. The first adhesive layer and the second adhesive layer cooperate to realize the dynamic protection and impact buffering of the lug connection part, and greatly improve the lug reliability of the battery pack under the conditions of falling impact and long-term use.

In one embodiment, the battery pack further comprises a top sealing part, the pole piece is positioned in the top sealing part, the pole lug comprises a first lug part and a second lug part, wherein,

The first lug is embedded in the top sealing part and connected with the pole piece, and the first adhesive layer coats the top sealing part;

The second ear is connected to one end of the first ear, which is far away from the pole piece, the second ear is exposed out of the top sealing part and connected with the busbar, and the second ear is coated by the second adhesive layer.

Through the adoption of the technical scheme, the electrode lug is divided into the first lug part embedded in the top sealing part and the exposed second lug part, the first lug part is coated by the flexible first adhesive layer, so that flexible follow-up protection can be realized when the battery cell expands, the second lug part is coated by the second adhesive layer, a rigid protective layer is formed in a busbar connection area, and the impact resistance of the exposed section of the electrode lug is enhanced. The structure effectively partitions different functional areas of the protective electrode lug, so that the internal flexible buffer and the external structural strength are complementary, and the overall durability and the anti-falling performance of the battery cell packaging area are improved.

In one embodiment, the first adhesive layer is a flexible adhesive and/or the second adhesive layer is a high-strength adhesive.

Through adopting above-mentioned technical scheme, through designing first glue film as flexible glue, second glue film design for high strength glue for the deformation of electric core in normal charge-discharge cycle in-process can be absorbed the buffering by flexible glue film, and when receiving external force impact, provide rigid support by high strength glue film, realize gentle-just combined multistage protection effect, promoted the reliability of utmost point ear welded part and the anti mechanical shock ability of module.

In one embodiment, the first adhesive layer is made of polyimide material or organic silicon material, and/or the second adhesive layer is made of epoxy resin material or polyurethane material.

By adopting the technical scheme, the first adhesive layer made of polyimide or organic silicon material has excellent flexibility, high temperature resistance and dielectric property, can keep stable adhesion when the pole piece expands and deforms, and the second adhesive layer made of epoxy resin or polyurethane material has high strength and excellent impact energy absorption property, and can rapidly disperse impact energy under a falling working condition. Through material characteristic matching, comprehensive protection of the high-altitude flight battery module under the working conditions of multi-field coupling such as temperature, stress and impact is realized.

In an embodiment, the thickness of the first adhesive layer in the height direction of the electric core is H1, and the thickness of the second adhesive layer in the height direction of the electric core is H2, wherein H1< H2.

Through adopting above-mentioned technical scheme, through setting first glue film thickness H1 to be less than second glue film thickness H2, form by gentle to just thickness gradient distribution, make the stress layer by layer transition of tab junction region, avoid because of the stress concentration that rigidity abrupt change leads to. The thickness design further improves the buffer coordination performance of the adhesive layer, and ensures the structural stability and the service life under different loads such as falling, vibration, cyclic expansion and the like.

In an embodiment, the battery pack further comprises a box body, a plurality of battery cells are arranged in the box body along the length direction of the box body, and the first adhesive layer and the second adhesive layer are respectively encapsulated between the battery cells and the inner top wall of the box body.

Through adopting above-mentioned technical scheme, set up first glue film and second glue film simultaneously between electric core and box, constitute the whole embedment system of module level, can absorb the impact energy between electric core and the box simultaneously, form multilayer buffering protection network. The structure can prevent the damage of the lug and the bus bar under the drop impact, and effectively improve the overall impact resistance and the service life of the battery pack.

In one embodiment, the box body is made of a composite of para-aramid fiber material and T700-grade carbon fiber material.

By adopting the technical scheme, the box body is made of the para-aramid fiber material and the T700-grade carbon fiber in a compounding way, so that the specific strength of the box body is about 10 times of that of the aluminum alloy, the specific rigidity of the box body is more than 5 times of that of the aluminum alloy, and the structural strength and the impact resistance of the box body are obviously improved. Meanwhile, the aramid fiber layer has excellent puncture resistance and tear resistance, can disperse energy when falling, protects an internal cell from structural deformation impact, and realizes balance of light weight and high protection.

In an embodiment, the battery pack further includes a non-newtonian fluid buffer layer filled between the case and the battery cell and between the battery cell and the battery cell.

By adopting the technical scheme, the non-Newtonian fluid buffer layer is filled between the battery cell and the box body and between the adjacent battery cells, the buffer layer is kept soft in a static state, and the molecular structure is instantaneously locked to form a rigid state when being impacted, so that impact force can be instantaneously absorbed and diffused, and the soft state can be recovered after the impact. The dynamic response characteristic enables the battery pack to efficiently absorb energy and buffer under the working condition that the aircraft falls or violently shakes, and the overall impact-resistant safety level is improved.

In one embodiment, the non-Newtonian fluid buffer layer is made of a polyglycol material and/or a polyglycol material.

By adopting the technical scheme, the energy absorption capacity of the non-Newtonian fluid buffer layer made of the polyglycol or the polytrialcohol is improved by about 6 times compared with that of the traditional EVA or polyurethane foam, the response speed is improved by 7 times under the high strain rate, and the high-efficiency energy absorption and dispersion can be realized when the aircraft falls down at a high speed or lands in an emergency, so that the impact resistance and the navigability safety of the battery pack are greatly improved.

In an embodiment, the box body is provided with a through hole for the lead of the battery cell to pass through, the periphery of the through hole on the box body is provided with a reinforcing ring, the periphery of the reinforcing ring on the box body is provided with a plurality of reinforcing ribs, and the reinforcing ribs are arranged in a reflection mode around the through hole.

Through adopting above-mentioned technical scheme, the box perforation periphery sets up the strengthening ring and the strengthening rib structure that the reflection form distributes, can effectively disperse the stress concentration in the area is worn out to the electric core lead wire, prevents to fall or the perforation position emergence crack growth in the vibration process. The radial reinforcing ribs can also guide the impact energy to spread to the outside of the box body, and enhance the fatigue resistance and the integral structural integrity of the key connection area.

In an embodiment, the corner regions of the box have a reinforcing structure, which is a three-dimensional honeycomb topology.

By adopting the technical scheme, the three-dimensional honeycomb topology reinforcing structure is arranged in the corner region of the box body, so that the bending resistance, shearing resistance and compression resistance of the region can be remarkably improved. The three-dimensional honeycomb topological structure can form multi-path energy dissipation channels when falling or side impact occurs, so that stress distribution is more uniform, local deformation or instability of the box body is prevented, and multi-directional protection is provided for the battery cell.

In an embodiment, the reinforcing structure includes a first wall surface, a second wall surface and reinforcing columns, a plurality of reinforcing columns are disposed between the first wall surface and the second wall surface, a first end of each reinforcing column is connected with the first wall surface, a second end of each reinforcing column is connected with the second wall surface, the reinforcing columns are arranged in a hollow mode, and a plurality of reinforcing columns are combined adjacently in sequence to form a honeycomb shape.

Through adopting above-mentioned technical scheme, through setting up a plurality of hollow spliced pole formation cellular structure between first wall and second wall, the spliced pole can take place controlled deformation energy-absorbing when the atress, makes the box can realize high energy absorption with less structural weight when bearing the impact. The cavity design further reduces the mass and the lifting ratio strength, and meets the structural requirement of eVTOL aircraft on light weight and impact resistance.

In an embodiment, the cross section of the reinforcing column is regular hexagon, the single-side length of the regular hexagon ranges from 2mm to 6mm, and the wall thickness of the reinforcing column ranges from 0.1mm to 0.5mm.

By adopting the technical scheme, the reinforcing column adopts the regular hexagon section and limits the parameter interval with the side length of 2mm to 6mm and the wall thickness of 0.1mm to 0.5mm, so that the reinforcing column has the optimal in-plane compression resistance and bending resistance while keeping the weight reduction. The design of the micro-scale honeycomb unit enables the whole box body to have quasi-isotropy mechanical characteristics, and the anti-drop impact capability is further improved.

In a second aspect, the present application further provides an electric device, including the battery pack according to the first aspect.

The embodiment of the application has the beneficial effects that:

1. And a first adhesive layer and a second adhesive layer with different elastic moduli are poured into the lug connection area to form a cooperative structure of flexible buffering and rigid supporting. The first adhesive layer is flexible adhesive with smaller elastic modulus, and covers the connection part of the pole piece and the pole lug, and moderate deformation can be generated along with volume expansion of the pole piece in the battery core circulation process so as to absorb stress fluctuation of the connection area and reduce fatigue fracture risk of the connection part of the pole lug and the pole piece, the second adhesive layer is high-strength adhesive with larger elastic modulus, and covers the connection part of the busbar and the pole lug, so that structural constraint and support can be provided under the effects of falling, vibration and impact load, and bending or fracture of the busbar and the pole lug under transient load is prevented. The elastic modulus gradient arrangement of the first adhesive layer and the second adhesive layer enables the lug area to be moderately buffered and reliably supported under two working conditions of cyclic deformation and external impact, so that the structural durability and the safety reliability of the battery module are improved to a certain extent;

2. The box body is made of a para-aramid fiber and T700-grade carbon fiber composite material, has the characteristics of high specific strength and high specific stiffness, is combined with a non-Newtonian fluid buffer layer arranged between the cell gap and the box body and the cell, and when falling or external impact is applied, molecular structures in the buffer layer are instantaneously locked to form a rigid body to absorb the impact energy, and the soft state is restored after the impact is finished, so that the energy concentration is reduced to a certain extent. The three-dimensional honeycomb topology reinforcing structure of the box body corner areas and the reflective reinforcing ribs surrounding the perforations further disperse stress paths, and stress concentration of the local structure is avoided. Through the synergistic effect of the flexible glue layer, the high-strength glue layer, the non-Newtonian fluid buffer layer and the composite box body, the battery pack has excellent shock resistance and structural integrity, can maintain a stable electric connection state under the use environment of the aircraft with large drop height and high impact strength, and meets the navigability requirement of high safety level.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is evident that the drawings in the following description are only some embodiments of the application and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.

For a more complete understanding of the present application and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts throughout the following description.

Fig. 1 is an internal cross-sectional view of a battery pack in an embodiment of the present application;

FIG. 2 is a partial schematic view of a tank in an embodiment of the application at a perforation;

FIG. 3 is an exploded perspective schematic view of a reinforcing structure in an embodiment of the present application;

FIG. 4 is a schematic illustration of a partial connection of a reinforcement column in an embodiment of the application.

Reference numerals illustrate:

1. The battery comprises a battery core, 11 electrode plates, 12 electrode lugs, 121, a first lug, 122 and a second lug;

2. a busbar;

3. A first adhesive layer;

4. a second adhesive layer;

5. A top seal;

6. The box body is provided with 61, perforations, 62, reinforcing rings, 63, reinforcing ribs, 64, a reinforcing structure, 65, a first wall surface, 66, a second wall surface and 67, a reinforcing column;

7. a non-newtonian fluid buffer layer.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by a person skilled in the art without any inventive effort, are intended to be within the scope of the present application based on the embodiments of the present application.

In a first aspect, referring to fig. 1, the battery pack includes a battery cell 1, a bus bar 2, a first adhesive layer 3 and a second adhesive layer 4, wherein the battery cell 1 includes a pole piece 11 and a pole tab 12, the pole tab 12 is connected to the pole piece 11, and the bus bar 2 is disposed at one end of the pole tab 12 away from the pole piece 11.

Illustratively, the first adhesive layer 3 is encapsulated in a gap between the bus bar 2 and the pole piece 11, and the first adhesive layer 3 encapsulates a connection part of the pole piece 11 and the pole lug 12, and further, the second adhesive layer 4 is encapsulated between the bus bar 2 and the first adhesive layer 3, and the second adhesive layer 4 encapsulates a connection part of the bus bar 2 and the pole lug 12.

The modulus of elasticity of the first glue layer 3 is illustratively a, and the modulus of elasticity of the second glue layer 4 is b, a < b.

It can be understood that the first adhesive layer 3 is softer than the second adhesive layer 4, that is, the flexible characteristic of the first adhesive layer 3 is beneficial to absorbing deformation energy of the battery cell 1 in the charge-discharge cycle, when the pole piece 11 expands, the pole piece 11 drives the pole lug 12 to generate micro displacement, and the first adhesive layer 3 responds to the displacement through self elastic expansion, so that the connection part of the pole lug 12 and the pole piece 11 is kept stable and not easy to break.

At the same time, the second adhesive layer 4 has higher hardness and higher elastic modulus than the first adhesive layer 3, and the second adhesive layer 4 provides stable supporting force when the battery pack is subjected to falling or vibration impact, thereby being beneficial to protecting the mechanical integrity of the connecting interface of the busbar 2 and the tab 12. The modulus difference between the first adhesive layer 3 and the second adhesive layer 4 forms a gradient buffer area, so that the stress is attenuated step by step in the transmission process, and the risk of fatigue damage to the lug 12 is reduced.

In some embodiments, as shown in fig. 1, the battery pack further includes a top seal 5, and the pole piece 11 is positioned within the top seal 5. Further, the top sealing part 5 is hollow and is used for protecting the pole piece 11, but the first adhesive layer 3 is partially filled into the top sealing part 5 during filling and sealing.

In some embodiments, the tab 12 includes a first ear portion 121 and a second ear portion 122, where the first ear portion 121 is embedded in the top sealing portion 5 and connected to the pole piece 11, and the second ear portion 122 is connected to one end of the first ear portion 121 away from the pole piece 11 and exposed out of the top sealing portion 5, and is electrically connected to the busbar 2. The first adhesive layer 3 covers the top sealing part 5 and the first lug 121 area to enable the connection area of the packaging end of the battery cell 1 to keep a flexible interface, the second adhesive layer 4 covers the connection position of the second lug 122 and the busbar 2, and a high-strength protective belt is formed at the exposed section.

It can be understood that by such a zoned design, the internal connection region of the cell 1 is flexibly buffered, while the relatively outer connection region of the cell 1 is rigidly supported, so that the cell 1 has a moderate deformation space and fracture resistance under the conditions of expansion and external impact. The adhesive layers on the inner side and the outer side of the top sealing part 5 are continuously transited, interface stripping caused by abrupt change of rigidity is avoided, and the sectional layout of the first lug part 121 and the second lug part 122 is also beneficial to precisely controlling the stress transmission path, so that the stress of the connecting area is more uniform.

Illustratively, the battery cell 1 further includes a core body, a majority of the pole piece 11 is located inside the core body, an electrochemical reaction body of the battery cell 1 is formed by a laminated structure, and a small portion of the pole piece 11 is led out from an upper end of the core body, and the section area is referred to as a tab. The leading lug is positioned in the inner position of the top sealing part 5 and is connected with the first lug 121 in a laser welding or ultrasonic welding mode and the like to form a conductive transition structure between the inner pole piece 11 of the battery cell 1 and the outer busbar 2.

In some embodiments, the first adhesive layer 3 is made of a flexible adhesive material, and the second adhesive layer 4 is made of a high-strength adhesive material. It should be noted that the high-strength adhesive in this embodiment refers to a cured structural adhesive with a higher elastic modulus and a higher shear strength, the tensile strength is generally not lower than 20MPa, the shear strength is not lower than 15MPa, and the elastic modulus can range from 500MPa to 2000MPa. The colloid has higher structural supporting capability and deformation resistance after solidification, and can maintain a stable connection structure of the busbar 2 and the tab 12 region under the action of external force impact or falling load.

The first glue layer 3 is made of polyimide material or silicone material, for example.

The second glue layer 4 is made of an epoxy material or a polyurethane material, for example.

It can be understood that the flexible glue material such as polyimide or organic silicon material has excellent heat resistance and flexibility, can maintain stable bonding state in a wider temperature range, has larger breaking elongation and can extend along with the expansion of the pole piece 11, while the high-strength glue material such as epoxy resin or polyurethane material has higher shear modulus and impact energy absorption performance, and can absorb and disperse external impact energy under the transient load. The material differential design establishes a functional layered system, so that the flexible layer bears a cyclic deformation buffering function, and the rigid layer bears a structural protection function, thereby maintaining the electrical property and mechanical stability of the connection part of the tab 12 under a complex working condition.

In some embodiments, the thickness of the first adhesive layer 3 in the height direction of the cell 1 is H1, and the thickness of the second adhesive layer 4 in the height direction of the cell 1 is H2, wherein H1< H2.

It can be understood that the thickness difference enables the adhesive layer to form a soft-to-rigid gradual change structure in the height direction, so that external force can be guided to be transmitted and attenuated layer by layer, and local stress peaks of interfaces are reduced. The thinner first adhesive layer 3 forms a controllable flexible area at the top of the battery cell 1, the thicker second adhesive layer 4 forms a high-energy absorption area at the outer layer, and the cooperative distribution of the two layers is beneficial to maintaining the overall morphological stability of the adhesive layer in the falling impact or structural vibration process, and meanwhile, the inner conductive connection area is not influenced by excessive stretching or shearing.

In some embodiments, referring to fig. 1, the battery pack further includes a case 6, and a plurality of electric cells 1 are disposed in the case 6 along a length direction of the case 6, and the first adhesive layer 3 and the second adhesive layer 4 are all encapsulated between the electric cells 1 and an inner top wall of the case 6.

It can be understood that the plurality of electric cores 1 of the battery pack are distributed along the length direction of the box body 6, the first adhesive layer 3 and the second adhesive layer 4 are encapsulated between the plurality of electric cores 1 and between the electric cores 1 and the inner top wall of the box body 6, and an integral encapsulating system is formed. After curing, the potting adhesive coats the upper surface of each cell 1 and the electrode lug 12 area, so that the array of the cells 1 forms a continuous elastic support network inside the box 6. The network can realize the cooperative response of local deformation and stress diffusion under the action of external force, has the dual functions of a buffer layer and structural adhesive, and is beneficial to improving the overall anti-seismic performance and thermal cycle stability of the module. When the array of the battery cells 1 is subjected to longitudinal falling impact, the first adhesive layer 3 firstly absorbs the initial energy of the impact, and the second adhesive layer 4 then further disperses residual stress through the high-strength structure of the second adhesive layer, so that the mechanical strain level of the single battery cells 1 is reduced.

In some embodiments, the box 6 is made of a composite of para-aramid fiber material and a T700 grade carbon fiber material. The para-aramid fiber layer has high specific strength and excellent impact resistance, can form a toughness protection area under the action of external impact to prevent crack growth, and the T700-level carbon fiber layer provides higher bending rigidity to ensure that the box body 6 structurally maintains an integral form. The composite structure is significantly lower in weight than the conventional metal box 6 and can maintain good deformation recovery performance in multiple drop or vibration tests. The carbon fiber layer and the aramid fiber layer are combined through high-temperature curing resin to form a layered stress system, so that stress is beneficial to diffusing along the interlayer surface under the action of external force, and the concentrated impact on the battery cell 1 is weakened. The design of the composite box 6 meets the double requirements of eVTOL aircraft for light weight and high strength.

In some embodiments, referring to fig. 1, a non-newtonian fluid buffer layer 7 is provided between the case 6 and the cell 1 and in the adjacent gap of the cell 1, and fills the structural gap and remains soft under normal conditions. When impacted by high-speed impact or acceleration, the molecular chain structure of the non-Newtonian fluid is instantaneously aligned and locked to form a temporary rigid state, absorbing and dispersing impact energy. After the impact is finished, the molecular chains are restored to an unordered state, so that the buffer layer is restored to the flexibility again. The strain response rate of the non-newtonian fluid is several orders of magnitude higher than that of conventional EVA or polyurethane foam, and yet still maintain effective energy absorbing performance at high impact rates. The buffer layer is introduced to ensure that the battery cell 1 can obtain dynamic adaptive protection under the conditions of falling, air current jolting or body vibration, and the energy absorption interval is obviously expanded.

In some embodiments, the non-newtonian fluid buffer layer 7 is made of a polyglycol or a polytrialcohol material, and the molecular structure of the material contains polyhydroxy branched chains, so that the material has excellent viscoelastic properties and reversible shear thickening effect. When the battery pack is impacted by different magnitudes, the intermolecular hydrogen bonding effect generates controllable structural change, so that the material is in a low-viscosity state at the initial stage of being stressed to buffer low-speed impact, and in a high-viscosity state at the later stage of being stressed to resist high-speed impact, thereby maintaining stable energy absorption performance in a wide speed interval. The energy absorption capacity of the material is about six times that of the traditional foam material, the high-speed strain force response efficiency is improved by about seven times, and the material is suitable for the extreme drop test requirement of eVTOL aircraft.

In some embodiments, as shown in fig. 1 and 2, a through hole 61 through which the lead of the power supply core 1 passes is provided in the case 6, a reinforcing ring 62 is provided at the periphery of the through hole 61, a plurality of reinforcing ribs 63 are uniformly distributed at the periphery of the through hole 61, and the reinforcing ribs 63 are arranged in a reflective manner around the through hole 61. The reinforcing ring 62 is used for reinforcing the local structural rigidity of the region of the through hole 61 and preventing the lead wire outgoing region of the battery cell 1 from generating cracks due to repeated vibration or impact. The reflective ribs 63 are designed to help direct stresses concentrated in the region of the perforations 61 radially to the wall of the tank 6, thereby distributing the impact energy over a greater range. The geometric match between the reinforcing ring 62 and the reinforcing ribs 63 is determined by finite element optimization so that the stress distribution is uniform and secondary concentration is not caused, which is beneficial to maintaining the tightness and structural integrity of the tank 6 for a long time.

In some embodiments, referring to fig. 1, 3 and 4, the corner regions of the case 6 have a reinforcing structure 64, and the reinforcing structure 64 is a three-dimensional honeycomb topology.

Illustratively, the reinforcing structure 64 includes a first wall 65, a second wall 66 and reinforcing columns 67, a plurality of reinforcing columns 67 are disposed between the first wall 65 and the second wall 66, a first end of each reinforcing column 67 is connected to the first wall 65, a second end of each reinforcing column 67 is connected to the second wall 66, the reinforcing columns 67 are hollow, and the reinforcing columns 67 are sequentially adjacently combined to form a honeycomb shape.

It will be appreciated that the reinforcement columns 67 are hollow in structure and that a plurality of reinforcement columns 67 are adjacently combined to form a honeycomb-like space unit. The geometric characteristics of the honeycomb topology enable the structure to show quasi-isotropic mechanical response when stressed, and are beneficial to absorbing multidirectional impact loads. The hollow reinforcing column 67 undergoes controllable micro buckling under the action of external force, and generates energy dissipation, which is beneficial to reducing the transmission of instantaneous impact stress to the main body of the box 6. The spacing between the first wall 65 and the second wall 66, the wall thickness of the reinforcing columns 67, and the arrangement density are designed by structural optimization to balance the honeycomb unit between mass, strength, and energy absorption performance.

In some embodiments, referring to fig. 1, 3 and 4, the cross-sectional shape of the reinforcing column 67 is a regular hexagon, and the single-side length of the regular hexagon ranges from 2mm to 6mm, and the wall thickness of the reinforcing column 67 ranges from 0.1mm to 0.5mm.

It will be appreciated that the reinforcement post 67 may achieve higher in-plane compression and bending stiffness while maintaining light weight. The continuous arrangement of the regular hexagonal structures forms a stable energy absorption path, and stresses are dispersed in multiple directions when impacted, avoiding concentration of stresses on a certain cell. Through the micro-scale design of the structure, the honeycomb area shows predictable buckling behavior under stress, and is beneficial to maintaining stable protective performance of the battery pack in multiple impact cycles.

In a second aspect, the present application also provides a powered device, including the battery pack of the first aspect.

It is understood that the battery pack is installed in electric equipment, and the electric equipment comprises high-altitude operation carriers such as aircrafts or unmanned aerial vehicles. The multi-stage buffer system of the battery pack comprises a flexible first adhesive layer 3, a rigid second adhesive layer 4, a non-Newtonian fluid buffer layer 7 and a composite material box body 6, and an energy attenuation chain is formed from inside to outside. The flexible layer absorbs micro-deformation energy, the rigid layer diffuses mechanical impact, the fluid layer provides dynamic response energy absorption, and the composite box 6 bears outer layer protection. The whole system maintains structural integrity in 15m drop test, maintains connection reliability of the battery cell 1 under high-frequency vibration and temperature difference circulation conditions, and meets the airworthiness safety requirement of an aircraft. The structural scheme is beneficial to improving the impact resistance and environmental adaptability of the battery pack on the premise of not obviously increasing the weight, and provides a stable power supply foundation for the electric vertical take-off and landing aircraft.

In the description of the present application, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments.

The embodiments, the implementation modes and the related technical features of the application can be mutually combined and replaced under the condition of no conflict.

The foregoing is only a preferred embodiment of the present application, and is not intended to limit the present application in any way, but any simple modification, equivalent variation and modification made to the above embodiment according to the technical matter of the present application still fall within the scope of the technical solution of the present application.

Claims (14)

1. A battery pack, comprising:

the battery cell (1) comprises a pole piece (11) and a pole lug (12), wherein the pole lug (12) is connected to the pole piece (11);

the busbar (2) is connected to one end of the tab (12) far away from the pole piece (11);

the first adhesive layer (3) is encapsulated between the busbar (2) and the pole piece (11), and the first adhesive layer (3) coats the connection part of the pole piece (11) and the pole lug (12);

a second adhesive layer (4) encapsulated between the busbar (2) and the first adhesive layer (3), wherein the second adhesive layer (4) coats the connection part of the busbar (2) and the tab (12),

The elastic modulus of the first adhesive layer (3) is a, and the elastic modulus of the second adhesive layer (4) is b, wherein a is smaller than b.

2. The battery pack according to claim 1, further comprising a top seal (5), wherein the pole piece (11) is positioned within the top seal (5), wherein the tab (12) comprises a first ear (121) and a second ear (122), wherein,

The first lug part (121) is embedded in the top sealing part (5) and is connected with the pole piece (11), and the first adhesive layer (3) coats the top sealing part (5);

the second lug (122) is connected to one end, far away from the pole piece (11), of the first lug (121), the second lug (122) is exposed out of the top sealing part (5) and connected with the busbar (2), and the second lug (122) is coated by the second adhesive layer (4).

3. The battery pack according to claim 1, wherein the first glue layer (3) is a flexible glue and/or the second glue layer (4) is a high-strength glue.

4. The battery pack according to claim 1, wherein the first adhesive layer (3) is made of a polyimide material or a silicone material, and/or the second adhesive layer (4) is made of an epoxy resin material or a polyurethane material.

5. The battery pack according to claim 1, wherein the thickness of the first adhesive layer (3) in the height direction of the battery cell (1) is H1, and the thickness of the second adhesive layer (4) in the height direction of the battery cell (1) is H2, wherein H1< H2.

6. The battery pack according to any one of claims 1 to 5, further comprising a case (6), wherein a plurality of the electric cells (1) are arranged in the case (6) along the length direction of the case (6), and the first adhesive layer (3) and the second adhesive layer (4) are respectively encapsulated between the electric cells (1) and the inner top wall of the case (6).

7. The battery pack according to claim 6, wherein the case (6) is made of a composite of para-aramid fiber material and T700 grade carbon fiber material.

8. The battery pack according to claim 6, further comprising a non-newtonian fluid buffer layer (7), the non-newtonian fluid buffer layer (7) being filled between the case (6) and the cell (1) and between the cell (1) and the cell (1).

9. The battery pack according to claim 8, wherein the non-newtonian fluid buffer layer (7) is made of a polyglycol material and/or a polytrialcohol material.

10. The battery pack according to claim 6, wherein the case (6) is provided with a through hole (61) through which the lead wire of the battery cell (1) passes, a reinforcing ring (62) is arranged on the case (6) and positioned on the periphery of the through hole (61), a plurality of reinforcing ribs (63) are arranged on the case (6) and positioned on the periphery of the reinforcing ring (62), and the reinforcing ribs (63) are arranged in a reflective manner around the through hole (61).

11. The battery pack according to claim 6, wherein the corner regions of the case (6) have a reinforcing structure (64), the reinforcing structure (64) being a three-dimensional honeycomb topology.

12. The battery pack according to claim 11, wherein the reinforcement structure (64) comprises a first wall surface (65), a second wall surface (66) and reinforcement columns (67), a plurality of reinforcement columns (67) are arranged between the first wall surface (65) and the second wall surface (66), a first end of each reinforcement column (67) is connected with the first wall surface (65), a second end of each reinforcement column is connected with the second wall surface (66), the reinforcement columns (67) are arranged in a hollow mode, and a plurality of reinforcement columns (67) are sequentially combined adjacently to form a honeycomb shape.

13. The battery pack according to claim 12, wherein the cross-sectional shape of the reinforcing column (67) is a regular hexagon, and the single-sided length of the regular hexagon ranges from 2mm to 6mm, and the wall thickness of the reinforcing column (67) ranges from 0.1mm to 0.5mm.

14. A powered device comprising a battery pack according to any one of claims 1 to 13.