Battery cell structure, secondary battery, and electric device

Abstract

The utility model belongs to battery technical field, concretely relates to a kind of electric core structure, secondary battery and electric equipment, wherein, the electric core structure includes bare electric core body and protection piece;Corner section is equipped on the bare electric core body;Protection piece is covered at least partial structure along the corner section on the outer side of circumferential direction, and the protection piece is connected on the outer side of corner section;And the protection piece is equipped with buffer gap.The utility model can improve the safety characteristic after lithium battery drop, and improve the security and stability of use.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, and in particular relates to a cell structure, a secondary battery, and an electrical device. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supplies, power storage, new energy storage power supplies, and aerospace and military industries due to their advantages such as large capacity, high operating voltage, strong charge retention, and long cycle life. Battery safety has always been a top priority in the industry. Batteries with better safety are more favored by the market, and major battery manufacturers and OEMs are competing to design high-safety battery products, verifying battery safety through tests such as drop tests.

[0003] However, during a fall, the corners of lithium batteries tend to hit the ground first, causing the corners to contract. This damage to the corners after the fall can easily lead to thermal runaway and fire, resulting in lower safety. Utility Model Content

[0004] The purpose of this utility model is to provide a battery cell structure that addresses the shortcomings of existing technologies and solves the technical problem of low safety in the use of existing technologies.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A battery cell structure includes a bare battery cell body and a protective component; the bare battery cell body has a corner segment; the protective component covers at least a portion of the outer side of the corner segment in the circumferential direction, and the protective component is connected to the outer side of the corner segment; and the protective component has a buffer gap.

[0007] Preferably, the corner segment has two oppositely arranged corner positions; the number of protective components is two, and they are respectively connected to different corner positions; and the two protective components are symmetrically arranged along the central axis of the corner segment.

[0008] Preferably, the outer circumferential surface of the protective component is provided with a first connecting straight surface, a second connecting straight surface, and an abutting arc surface arranged sequentially; and the abutting arc surface is connected to the corner segment; the first connecting straight surface and the second connecting straight surface are inclined; the second connecting straight surface and the abutting arc surface are inclined; the first connecting straight surface and the abutting arc surface are inclined.

[0009] Preferably, the protective component further includes a first connecting straight surface, a connecting curved surface, and a second connecting straight surface; the first connecting straight surface is connected to the second connecting straight surface through the connecting curved surface; the first connecting straight surface is connected to the abutting arc surface through the first connecting straight surface; and the second connecting straight surface is connected to the abutting arc surface through the second connecting straight surface.

[0010] Preferably, the protective component is selected from one of epoxy resin composite material, polyimide, polyarylether, polyetheretherketone, carbon fiber reinforced composite material, and aramid fiber reinforced composite material.

[0011] Preferably, the relationship between the width d0 of the bare battery cell body and the width d1 of the protective component satisfies: d1=d0*B; where B is 0.3~0.45;

[0012] And / or, the relationship between the thickness W0 of the bare cell body and the thickness W1 of the protective component satisfies: W1 = W0 * C; where C is 0.3 to 0.45;

[0013] And / or, the fillet radius R of the protective element satisfies: 0.25mm ≤ R ≤ 0.5mm;

[0014] And / or, the relationship between the material strength N of the protective component and the cross-sectional area S of the protective component satisfies: 0.9≤N / (10*S)≤1.5.

[0015] Preferably, the relationship between the height L1 of the bare cell body and the height L2 of the protective component satisfies: L2=L1*D; where D satisfies: 0.95≤D≤0.99.

[0016] Preferably, the protective component has an assembly gap that extends across the protective component along a direction intersecting the circumferential direction, forming a first segment and a second segment that are positioned opposite each other.

[0017] The relationship between the height L3 of the first segment or the second segment and the height L1 of the bare cell body satisfies: L3=E*L1; where E satisfies: 0.2≤E≤0.3.

[0018] This utility model also discloses a secondary battery, including the cell structure described above.

[0019] This utility model also discloses an electrical device, including the aforementioned secondary battery.

[0020] The beneficial effects of this utility model are that by adding protective components at the corner of the battery, the overall rigidity of the cell structure can be effectively improved. In addition, the buffer gap added between two adjacent protective components helps to reduce the direct contact and stress transmission between the protective components during the drop impact, thereby reducing the secondary damage to the cell body caused by the deformation of the protective components. This not only effectively alleviates the degree of structural damage to the battery at the corner after a drop, but also significantly improves the safety and structural stability of lithium-ion batteries in drop tests and actual use. Attached Figure Description

[0021] The following will refer to the appendix. Figures 1-5 This section describes the features, advantages, and technical effects of exemplary embodiments of the present invention.

[0022] Figure 1 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention;

[0024] Figure 3 This is a front view of the cell structure of one embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the protective component of a battery cell structure according to an embodiment of the present invention;

[0026] Figure 5 This is a front view of the cell structure according to another embodiment of the present invention.

[0027] In the diagram: 1-bare cell body; 11-corner segment; 12-edge corner; 2-protective component; 201-abutting arc surface; 202-first connecting straight surface; 203-first connecting straight surface; 205-second connecting straight surface; 204-connecting curved surface; 206-second connecting straight surface; 3-buffer gap; 4-assembly gap. Detailed Implementation

[0028] 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 intended to particularly describe embodiments and not to limit the scope of this 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.

[0029] 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 embodiment description, "multiple" refers to two or more, unless otherwise specifically defined.

[0030] The term 'embodiment' means that a particular feature, structure, or characteristic described exists 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] 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, or multiple situations existing alone. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.

[0032] 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 also refer to a mechanical connection or an electrical connection. They can be directly connected or indirectly connected through an intermediate medium, manifesting as internal communication between two components or an 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.

[0033] The following is in conjunction with the appendix Figures 1-5 The present invention will be described in further detail, but this is not intended to limit the scope of the present invention.

[0034] like Figure 1 As shown, in one embodiment of this utility model, the battery cell structure includes a bare battery cell body 1 and at least two protective members 2. The bare battery cell body 1 has at least one corner segment 11. The protective member 2 covers at least a portion of the outer surface of the corner segment 11 in the circumferential direction A, and is connected to the outer surface of the corner segment 11. The protective member 2 also has a buffer gap 3. In some embodiments, the number of corner segments 11 is two, and they are respectively located at the left and right ends of the bare battery cell body 1.

[0035] The technical solution of this utility model effectively improves the overall rigidity of the battery cell structure by adding protective components at the corner of the battery. Combined with the buffer gap added between two adjacent protective components, it helps to reduce the direct contact and stress transmission between the protective components during drop impact, thereby reducing secondary damage to the battery cell body caused by the deformation of the protective components. This not only effectively alleviates the degree of structural damage to the battery at the corner after a drop, but also significantly improves the safety and structural stability of lithium-ion batteries in drop tests and actual use.

[0036] The bare cell body 1 includes a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive current collector and a positive active material layer, the latter coated on the surface of the current collector. The current collector can be made of aluminum, and the active material layer includes a positive active material, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode includes a negative current collector and a negative active material layer, the latter coated on the surface of the current collector. The current collector can be made of copper, and the active material layer includes a negative active material, such as carbon or silicon. The separator can be made of PP (polypropylene) or PE (polyethylene).

[0037] Specifically, in some embodiments, the protective component 2 is selected from one of ultra-high molecular weight polyethylene (UHMWPE), epoxy resin composite material, polyimide (PI), polyarylene ether (PAE), polyether ether ketone (PEEK), carbon fiber reinforced composite material, and aramid fiber reinforced composite material. UHMWPE is a polyethylene material with extremely high molecular weight, typically above 3 million; it possesses high impact strength and tensile strength. Carbon fiber reinforced composite material is a high-strength, high-modulus polymer material composed of carbon fibers and a matrix resin, exhibiting excellent mechanical properties. Aramid fiber reinforced composite material is composed of aramid fibers as reinforcement and a matrix resin; it possesses high strength, high modulus, and good heat resistance. Polyimide is a high-performance polymer material with excellent thermal stability, mechanical properties, and chemical stability. Epoxy resin composite material is a composite material made by adding appropriate reinforcing materials (such as glass fiber, carbon fiber, etc.) to an epoxy resin matrix; it possesses good mechanical properties. This structure uses a high-strength polymer material protective component 2 to regulate the force on the battery cell, thereby mitigating the damage to the corner section after a battery drop, and improving the safety characteristics of the lithium battery after a drop, thus enhancing its safety and stability in use.

[0038] Specifically, in some implementations, such as Figure 1 and 2As shown, the corner segment 11 has two oppositely arranged corner positions 12; there are two protective members 2, each connected to the corresponding corner position 12; and the two protective members 2 are symmetrically arranged along the central axis A of the corner segment 11. Each protective member 2 is bonded to the corner position 12. This structure effectively buffers external stress by protecting the corner segment 11 with the two oppositely arranged protective members 2, and also reduces the overall weight, thereby improving cycle life.

[0039] Specifically, in some implementations, such as Figure 2 and 4 As shown, the outer surface of the protective component 2 in the circumferential direction B is provided with a first connecting straight surface 203, a second connecting straight surface 205, and an abutting arc surface 201 arranged sequentially; and the abutting arc surface 201 is connected to the corner position 12 in the corner segment 11; the first connecting straight surface 203 and the second connecting straight surface 205 are inclined; the second connecting straight surface 205 and the abutting arc surface 201 are inclined; the first connecting straight surface 203 and the abutting arc surface 201 are inclined. In some embodiments, such as... Figure 4 As shown, the first connecting straight surface 203 and the second connecting straight surface 205 are perpendicularly arranged. This structure, with the inner side being an abutting arc surface 201 combined with the upper side forming a right angle surface, ensures the stability of assembly with the inner bare cell body, and also ensures the stability of assembly with the outer casing and other structures. Furthermore, the pressing and shaping pressure between the abutting arc surface 201 and the bare cell body 1 meets the requirement of 0.2~0.45MPa.

[0040] Furthermore, in some embodiments, the protective component 2 further includes a first connecting straight surface 202, a connecting curved surface 204, and a second connecting straight surface 206; the first connecting straight surface 203 is connected to the second connecting straight surface 205 via the connecting curved surface 204; the first connecting straight surface 203 is connected to the abutting arc surface 201 via the first connecting straight surface 202; the second connecting straight surface 205 is connected to the abutting arc surface 201 via the second connecting straight surface 206. That is, both ends of the connecting curved surface 204 are connected to the first connecting straight surface 203 and the second connecting straight surface 205; both ends of the first connecting straight surface 202 are connected to the first connecting straight surface 203 and the abutting arc surface 201; both ends of the second connecting straight surface 206 are connected to the abutting arc surface 201 and the second connecting straight surface 205. This structure, through the connection of the first connecting straight surface 202, the connecting curved surface 204, and the second connecting straight surface 206, adjusts the force on the battery cell to alleviate the damage to the corner section after the battery falls, thereby improving the safety characteristics of the lithium battery after a fall and enhancing the safety and stability of its use.

[0041] Specifically, in some implementations, such as Figure 1 and 2As shown, the relationship between the width d0 of the bare cell body 1 and the width d1 of the protective component 2 satisfies: d1 = d0 * B; where B is 0.3 to 0.45. Further, the width d0 of the bare cell body 1 satisfies: 50mm ≤ d0 ≤ 100mm. That is, d0 can be 50mm, 55mm, 60mm, 70mm, 80mm, 90mm, 93mm, 95mm, 100mm, etc.; preferably 80mm. B can be 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.40, 0.42, 0.44, 0.45, etc.; preferably 0.35. This structure ensures stability and safety through appropriate widths of the bare cell body 1 and the protective component 2. If d1 is too large, the material will exceed the corner area, affecting the cell thickness; if d1 is too small, the structural reinforcement effect will be small. When the bare cell body 1 is placed horizontally, its width is the dimension in the horizontal direction.

[0042] Specifically, in some implementations, such as Figure 1 and 2 As shown, the relationship between the thickness W0 of the bare cell body 1 and the thickness W1 of the protective component 2 satisfies: W1 = W0 * C; where C is 0.3 to 0.45. Further, the thickness W0 of the bare cell body 1 satisfies: 6mm ≤ d0 ≤ 10mm. That is, W0 can be 5mm, 5.5mm, 6.0mm, 7.0mm, 8.0mm, 9.0mm, 9.3mm, 9.5mm, 10.0mm, etc.; preferably 8.0mm. When the bare cell body is too thin, the corner space is insufficient, resulting in a smaller improvement benefit; when the bare cell body is too thick, the corner space is too large, resulting in a smaller improvement benefit. And C can be 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.40, 0.42, 0.44, 0.45, etc.; preferably 0.35. This structure ensures stability and safety through appropriate thicknesses of the bare cell body 1 and the protective component 2. Furthermore, an excessively large W1 will cause the material to extend beyond the corner edge, affecting the cell width; an excessively small W1 will result in insufficient structural reinforcement. When the bare cell body 1 is placed horizontally, its thickness refers to the dimension along the height direction.

[0043] Specifically, in some implementations, such as Figure 2 and 3As shown, the relationship between the height L1 of the bare cell body 1 and the height L2 of the protective component 2 satisfies: L2 = L1 * D; where D satisfies: 0.95 ≤ D ≤ 0.99. Furthermore, D can be: 0.95, 0.96, 0.97, 0.98, 0.985, 0.99, etc.; preferably 0.97. This structure can effectively protect the corner segment 11 through the protective component 2 of appropriate height. If L2 is too small, the corner cannot be protected; if L2 is too large, it affects the length of the cell. When the bare cell body 1 is placed upright, the height is the vertical dimension.

[0044] Specifically, in some implementations, such as Figure 2 and 4 As shown, the fillet radius R of the connecting curved surface 204 in the protective component 2 satisfies: 0.25mm ≤ R ≤ 0.5mm. R can be 0.25mm, 0.35mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.495mm, 0.5mm, etc.; preferably 0.25mm. If the fillet radius R of this structure is too small, it is easy to puncture the aluminum-plastic film; if it is too large, it weakens the strength.

[0045] Specifically, in some implementations, such as Figure 2 and 4 As shown, the relationship between the material strength N of the protective component 2 and the cross-sectional area S of the protective component 2 satisfies: 0.9≤N / (10*S)≤1.5; where N / (10*S)=0.9, N / (10*S)=1.1, N / (10*S)=1.2, N / (10*S)=1.3, N / (10*S)=1.4, N / (10*S)=1.45, N / (10*S)=1.5, etc.

[0046] Specifically, in some implementations, such as Figure 5 As shown, each protective component 2 has an assembly gap 4 at its midpoint in the height direction. The assembly gap 4 is arranged across the protective component 2 along a direction intersecting the circumferential direction, thus realizing the vertically opposed first and second segments. This structure breaks the protective component 2 in the middle through the assembly gap 4 to form the vertically opposed first and second segments, thereby effectively reducing the overall weight and ensuring protective performance, thereby improving the weight energy density. In some embodiments, the relationship between the height L3 of the first or second segment and the height L1 of the bare cell body 1 satisfies: L3 = E * L1; where E satisfies: 0.2 ≤ E ≤ 0.3. Further, E can be 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, etc.; preferably 0.25. This structure, through the rationally designed first or second segments, can effectively reduce the overall weight and ensure protective performance, thereby improving the weight energy density.

[0047] However, drop tests were conducted on battery cells with and without protective plates; and for battery cells with protective plates that met the condition that the relationship between the material strength N and the cross-sectional area S of the protective component 2 is 0.9≤N / (10*S)≤1.5; the specific values ​​are shown in the table below:

[0048]

[0049]

[0050] Therefore, this technical solution can achieve the following: 1. Using the space of the corner section 11 of the wound battery to add a protective component 2 with enhanced function to protect the corner of the battery cell; it can also make full use of the spare space inside the battery without affecting the volumetric energy density of the battery cell; and the protective component 2 with enhanced function fits the arc of the corner of the battery cell, so that the impact force after a drop is distributed by the entire arc surface of the battery cell, reducing the damage to the battery cell.

[0051] 2. The corner reinforcement structure fits the corner curvature of the battery cell, so that the impact force after a drop is distributed across the entire curved surface of the battery cell, reducing damage to the battery cell.

[0052] This utility model also proposes a secondary battery, which includes a cell structure. The specific structure of the cell structure is as described in the above embodiments. Since this secondary battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0053] A rechargeable battery, also known as a secondary battery or accumulator, is a battery that can be recharged after being discharged, allowing the active materials to be reactivated and reused. Utilizing the reversibility of chemical reactions, a new battery can be constructed; that is, after a chemical reaction converts into electrical energy, the electrical energy can be used to repair the chemical system, and then the chemical reaction can be converted back into electrical energy. Therefore, it is called a secondary battery (rechargeable battery). The main types of rechargeable batteries on the market include nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid (or lead-acid) batteries, lithium-ion batteries, and polymer lithium-ion batteries.

[0054] The present invention also proposes an electrical device, which includes a secondary battery. The specific structure of the secondary battery is as described in the above embodiments. Since the present electrical device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0055] The electrical equipment 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 special limitations on the above-mentioned electrical equipment.

[0056] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0057] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on this utility model are within the protection scope of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A battery cell structure, characterized in that: The device includes a bare battery cell body and a protective component; the bare battery cell body has a corner segment; the protective component covers at least a portion of the outer side of the corner segment in the circumferential direction, and the protective component is connected to the outer side of the corner segment; and the protective component has a buffer gap.

2. The cell structure according to claim 1, characterized in that: The corner segment has two opposite corner positions; there are two protective components, which are respectively connected to different corner positions; and the two protective components are symmetrically arranged along the central axis of the corner segment.

3. The cell structure according to claim 1 or 2, characterized in that: The outer circumferential surface of the protective component is provided with a first connecting straight surface, a second connecting straight surface, and an abutting arc surface arranged sequentially; and the abutting arc surface is connected to the corner segment; the first connecting straight surface and the second connecting straight surface are inclined; the second connecting straight surface and the abutting arc surface are inclined; the first connecting straight surface and the abutting arc surface are inclined.

4. The cell structure according to claim 3, characterized in that: The protective component further includes a first connecting straight surface, a connecting curved surface, and a second connecting straight surface; the first connecting straight surface is connected to the second connecting straight surface through the connecting curved surface; the first connecting straight surface is connected to the abutting arc surface through the first connecting straight surface; and the second connecting straight surface is connected to the abutting arc surface through the second connecting straight surface.

5. The cell structure according to claim 1, characterized in that: The protective component is selected from one of the following: epoxy resin composite material, polyimide, polyarylene ether, polyether ether ketone, carbon fiber reinforced composite material, and aramid fiber reinforced composite material.

6. The cell structure according to claim 1, characterized in that: The relationship between the width d0 of the bare battery cell body and the width d1 of the protective component satisfies: d1 = d0 * B; where B is 0.3 to 0.

45. And / or, the relationship between the thickness W0 of the bare cell body and the thickness W1 of the protective component satisfies: W1 = W0 * C; where C is 0.3 to 0.45; And / or, the fillet radius R of the protective element satisfies: 0.25mm ≤ R ≤ 0.5mm; And / or, the relationship between the material strength N of the protective component and the cross-sectional area S of the protective component satisfies: 0.9≤N / (10*S)≤1.

5.

7. The cell structure according to claim 1 or 6, characterized in that: The relationship between the height L1 of the bare battery cell body and the height L2 of the protective component satisfies: L2=L1*D; where D satisfies: 0.95≤D≤0.

99.

8. The cell structure according to claim 1 or 6, characterized in that: The protective component has an assembly gap, which is provided across the protective component along a direction intersecting the circumferential direction to form a first segment and a second segment that are arranged opposite to each other. The relationship between the height L3 of the first segment or the second segment and the height L1 of the bare cell body satisfies: L3=E*L1; where E satisfies: 0.2≤E≤0.

3.

9. A secondary battery, characterized in that: Includes the cell structure described in any one of claims 1 to 8.

10. An electrical appliance, characterized in that: Includes the secondary battery as described in claim 9.

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