Battery cell structure, lithium ion battery and power utilization device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery cell structure, a lithium ion battery and an electric device, the battery cell structure comprises a first pole piece, a second pole piece and a diaphragm, and the first pole piece, the diaphragm and the second pole piece are sequentially overlapped and wound to form a roll core; first ending glue is adhered to the side part of the roll core, a thermosensitive coating is coated on one surface, facing the outer side of the roll core, of the first ending glue, a flame retardant layer is coated on the surface of the thermosensitive coating, and second ending glue is adhered to the surface of the flame retardant layer. By optimizing the battery cell structure, the problem of thermal runaway of the battery can be relieved, and the quality of the battery can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to a battery core structure, a lithium-ion battery and an electrical device. Background Art

[0002] Nowadays, lithium-ion batteries, as a new type of secondary battery, have the advantages of high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and green environmental protection. They have broad application prospects in portable appliances, power tools, large-scale energy storage, electric transportation power supply, etc.

[0003] The needle puncture safety performance of cylindrical batteries has attracted much attention and is one of the battery cell safety test items required by national standards.

[0004] In the process of realizing the present invention, the inventors found that the prior art has at least the following problems:

[0005] When an existing cylindrical battery cell is punctured by a needle, the winding core has no fixing and protection structure, and the positive and negative poles are easily short-circuited, causing an internal short circuit, which causes the internal temperature of the battery to rise sharply, resulting in thermal runaway, and the battery cell is prone to fire, explosion, and other phenomena. Utility Model Content

[0006] One of the purposes of the present invention is to address the deficiencies of the prior art and provide a battery cell structure that can alleviate the problem of thermal runaway of the battery by optimizing the battery cell structure, thereby helping to improve the quality of the battery.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A battery cell structure includes a first electrode piece, a second electrode piece and a diaphragm, wherein the first electrode piece, the diaphragm and the second electrode piece are stacked in sequence and wound to form a winding core; a first finishing glue is adhered to the side of the winding core, a side of the first finishing glue facing the outside of the winding core is coated with a thermosensitive coating, a surface of the thermosensitive coating is coated with a flame retardant layer, and a second finishing glue is adhered to the surface of the flame retardant layer.

[0009] Preferably, the first finishing glue, the heat-sensitive coating, the flame retardant layer and the second finishing glue are sequentially arranged around the side of the winding core.

[0010] Preferably, the thermosensitive coating is in contact with the flame retardant layer, the first finishing glue is in contact with the side of the core facing the inner side of the core, and the second finishing glue is coated with the flame retardant layer on the inner side of the core.

[0011] Preferably, the battery cell structure further includes a shell, the winding core is arranged in the shell, and the sum of the radius of the winding core, the thickness of the thermosensitive coating, the thickness of the flame retardant layer and the thickness of the second finishing glue is smaller than the radius of the shell.

[0012] Preferably, the diaphragm has a tail end, the tail end is located at the outermost circle of the winding core, and the first tail glue is adhered to the side of the tail end facing the outer side of the winding core.

[0013] Preferably, the number of windings of the tail end of the diaphragm is 1 to 2, and the number of windings of the first tail end glue is at least 1.

[0014] Preferably, the cross-section of the winding core is circular, oval or square.

[0015] Preferably, the flame retardant layer is a gel structure.

[0016] A second object of the present invention is to provide a lithium-ion battery comprising the above-mentioned battery cell structure.

[0017] A third object of the present invention is to provide an electrical device comprising the above-mentioned lithium-ion battery.

[0018] One of the above technical solutions has the following beneficial effects:

[0019] The utility model optimizes the battery cell structure and applies a heat-sensitive coating and a flame retardant layer between the first finishing glue and the second finishing glue respectively. When the battery cell is pierced by a needle, the heat rises, and the heat-sensitive coating can expand or melt at high temperature, wrapping the short-circuit point between the steel needle and the positive and negative electrodes of the battery, reducing the contact area between the steel needle and the positive and negative electrodes, and alleviating the short-circuit reaction in the battery, thereby improving the needle penetration rate of the cylindrical battery cell. At the same time, the flame retardant layer can melt into a liquid and flow into the interior of the battery cell, which can block the thermal runaway of the battery and prevent the battery cell from catching fire, exploding, etc. Among them, the utility model adopts a double-layer structure consisting of the first finishing glue and the second finishing glue, which can fix the core and prevent the core from being damaged or deformed. In addition, the double-layer finishing glue can provide double-layer protection for the core, which helps to improve the safety performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0021] Figure 1 It is a structural diagram of the present utility model.

[0022] The description of the accompanying drawings is as follows:

[0023] 1- core;

[0024] 2-First finishing glue;

[0025] 3-Thermosensitive coating;

[0026] 4-flame retardant layer;

[0027] 5-Second finishing glue;

[0028] X-towards the inner side of the core;

[0029] Y-towards the outside of the core. DETAILED DESCRIPTION

[0030] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0031] Furthermore, the terms “first,” “second,” etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0032] In this utility model, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings, but the accompanying drawings are not intended to limit the present invention.

[0034] Implementation Method 1

[0035] Because when the existing cylindrical battery cell is pierced by a needle, the winding core has no fixing and protection structure, the positive and negative poles are easily short-circuited, causing an internal short circuit, which causes the internal temperature of the battery to rise sharply, resulting in thermal runaway, and the battery cell is prone to fire, explosion, etc.

[0036] The battery cell structure of the present invention includes a first electrode piece, a second electrode piece and a diaphragm. The first electrode piece, the diaphragm and the second electrode piece are stacked and wound in sequence to form a winding core 1; a first finishing glue 2 is pasted on the side of the winding core 1, and the first finishing glue 2 is coated with a heat-sensitive coating 3 on the side facing the outer direction Y of the winding core. The surface of the heat-sensitive coating 3 is coated with a flame retardant layer 4, and the surface of the flame retardant layer 4 is pasted with a second finishing glue 5. The utility model optimizes the battery cell structure and coats a heat-sensitive coating 3 and a flame retardant layer 4 between the first finishing glue 2 and the second finishing glue 5 respectively. When the battery cell is pierced by a needle, the heat rises, and the heat-sensitive coating 3 can expand or melt at high temperature, wrapping the short-circuit point between the steel needle and the positive and negative electrodes of the battery, reducing the contact area between the steel needle and the positive and negative electrodes, alleviating the short-circuit reaction in the battery, and improving the needle penetration rate of the cylindrical battery cell. At the same time, the flame retardant layer 4 can melt into a liquid and flow into the battery cell, which can block the thermal runaway of the battery and prevent the battery cell from catching fire, exploding, etc. Among them, the utility model adopts a double-layer structure composed of the first finishing glue 2 and the second finishing glue 5, which can fix the core 1 and prevent the core 1 from being damaged or deformed; in addition, the double-layer finishing glue can provide double-layer protection for the core 1, which helps to improve the safety performance of the battery cell.

[0037] It should be noted that the material and thickness of the first finishing glue 2 and the second finishing glue 5 are consistent. The first finishing glue 2 adopts a single-sided coating structure, that is, the side of the first finishing glue 2 facing the inner side direction X of the core is directly in contact with the side of the core 1, and the side of the first finishing glue 2 facing the outer side direction Y of the core is coated with a heat-sensitive coating 3; the second finishing glue 5 is also a single-sided coating structure, and the side of the second finishing glue 5 facing the inner side direction X of the core is coated with a flame retardant layer 4, and the side of the second finishing glue 5 facing the outer side direction Y of the core is not coated with the flame retardant layer 4, and this surface serves as the outermost layer of the battery cell and plays an insulating role.

[0038] In the battery cell structure according to the present invention, the first finishing adhesive 2, the heat-sensitive coating 3, the flame retardant layer 4, and the second finishing adhesive 5 are sequentially arranged around the side of the core 1. Specifically, the first finishing adhesive 2, the heat-sensitive coating 3, the flame retardant layer 4, and the second finishing adhesive 5 form a four-layer structure, which covers the side of the core 1 in accordance with the law. The side of the core 1 is the cylindrical surface of the core 1. The first finishing adhesive 2, the heat-sensitive coating 3, the flame retardant layer 4, and the second finishing adhesive 5 form a four-layer structure outside the cylindrical surface of the core 1. The first finishing adhesive 2 is located in the innermost layer, the heat-sensitive coating 3 is located in the second innermost layer, the flame retardant layer 4 is located in the second outermost layer, and the second finishing adhesive is located in the outermost layer.

[0039] In the battery core structure according to the present invention, the thermosensitive coating 3 and the flame retardant layer 4 are in contact with each other, and the thermosensitive coating 3 and the flame retardant layer 4 are respectively coated in the double-layer finishing glue. The thermosensitive coating 3 and the flame retardant layer 4 are in contact with each other, and both are layered structures at normal temperature, and deform at high temperature.

[0040] In the battery cell structure according to the present invention, the cell structure also includes an outer shell, within which the core 1 is disposed. The sum of the radius of the core 1, the thickness of the heat-sensitive coating 3, the thickness of the flame retardant layer 4, and the thickness of the second finishing adhesive 5 is less than the radius of the outer shell. Specifically, to facilitate installation within the outer shell, the outer shell radius is larger than the radius of the core 1, and space is reserved for the thickness of the heat-sensitive coating 3, the thickness of the flame retardant layer 4, and the thickness of the second finishing adhesive 5. Furthermore, the core 1 is cylindrical, and the outer shell is preferably cylindrical, preferably aluminum. However, this is not limiting to the present invention, and the shape and material of the outer shell can be adjusted according to the actual battery structure.

[0041] In the battery cell structure according to the present invention, the flame retardant layer 4 preferably adopts a gel structure, which can melt into liquid and flow into the battery cell, thereby blocking thermal runaway of the battery and preventing the battery cell from catching fire, exploding, etc.

[0042] The working principle of this utility model is:

[0043] The utility model optimizes the battery cell structure and coats a heat-sensitive coating 3 and a flame retardant layer 4 between the first finishing glue 2 and the second finishing glue 5 respectively. When the battery cell is pierced by a needle, the heat rises, and the heat-sensitive coating 3 can expand or melt at high temperature, wrapping the short-circuit point between the steel needle and the positive and negative electrodes of the battery, reducing the contact area between the steel needle and the positive and negative electrodes, alleviating the short-circuit reaction in the battery, and improving the needle penetration rate of the cylindrical battery cell. At the same time, the flame retardant layer 4 can melt into a liquid and flow into the battery cell, which can block the thermal runaway of the battery and prevent the battery cell from catching fire, exploding, etc. Among them, the utility model adopts a double-layer structure composed of the first finishing glue 2 and the second finishing glue 5, which can fix the core 1 and prevent the core 1 from being damaged or deformed; in addition, the double-layer finishing glue can provide double-layer protection for the core 1, which helps to improve the safety performance of the battery cell.

[0044] Implementation Method 2

[0045] Unlike the first embodiment, the diaphragm in this embodiment has a tail end, which is located at the outermost circle of the winding core 1. A first tail glue 2 is adhered to the side of the tail end facing the outer side of the winding core 1. The number of winding turns of the tail end of the diaphragm is 1 to 2, and the number of winding turns of the first tail glue 2 is at least 1. Specifically, the tail end of the diaphragm is wound around the winding core 1 one or two times, preferably 1.5 times, and is adhered to the tail end by the first tail glue 2 to prevent displacement of the tail end of the diaphragm. Accordingly, the first tail glue 2 wraps around the winding core 1 at least once, ensuring that the first tail glue 2 completely covers the side of the winding core 1, thereby fixing the winding core 1 and preventing damage or deformation of the winding core 1.

[0046] The other structures are the same as those in the first embodiment and will not be described again here.

[0047] Implementation Method 3

[0048] Different from the first embodiment, the cross-section of the core 1 of this embodiment is circular, elliptical or square. The core 1 preferably adopts a cylindrical structure, and the cross-section of the core 1 is circular, but the present invention is not limited to this. The structure in which the heat-sensitive coating 3 and the flame retardant layer 4 are respectively coated between the first finishing glue 2 and the second finishing glue 5 can also be applied to batteries with other cross-sectional shapes.

[0049] The other structures are the same as those in the first embodiment and will not be described again here.

[0050] lithium-ion batteries

[0051] The utility model includes battery core structures of embodiments one to three.

[0052] Specifically, the battery includes a first electrode sheet, a diaphragm and a second electrode sheet, which are wound in sequence to form a bare cell.

[0053] The battery is packaged in an aluminum shell, and the first and second pole pieces are provided with tabs respectively. The positions of the two sets of tabs correspond to the positive and negative poles on the aluminum shell or cover.

[0054] In order to avoid short circuit between the positive and negative pole pieces, a diaphragm is provided between each two adjacent pole pieces, and the pole pieces with opposite polarities are electrically isolated by the diaphragm.

[0055] The first electrode may be a positive electrode, and the second electrode may be a negative electrode; or, the first electrode may be a negative electrode, and the second electrode may be a positive electrode, which is not limited here.

[0056] Electrical devices

[0057] The battery containing the cell structure of the present invention can also be used in different electrical devices, and the electrical equipment can be cars, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and electric tools, etc. Cars can be fuel cars, gas cars or new energy cars, and new energy cars can be pure electric cars, hybrid cars or extended-range cars, etc.; spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0058] Based on the disclosure and teachings of the above description, those skilled in the art will be able to make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention fall within the scope of protection of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation on the present invention.

Claims

1. A battery cell structure, characterized in that: include: A first pole piece, a second pole piece and a diaphragm, wherein the first pole piece, the diaphragm and the second pole piece are stacked in sequence and wound to form a winding core (1); A first finishing glue (2) is adhered to the side of the winding core (1); a heat-sensitive coating (3) is coated on the side of the first finishing glue (2) facing the outside of the winding core (1); a flame retardant layer (4) is coated on the surface of the heat-sensitive coating (3); and a second finishing glue (5) is adhered to the surface of the flame retardant layer (4).

2. A battery cell structure according to claim 1, characterized in that: The first finishing glue (2), the heat-sensitive coating (3), the flame retardant layer (4) and the second finishing glue (5) are sequentially arranged around the side of the winding core (1).

3. A battery cell structure according to claim 2, characterized in that: The heat-sensitive coating (3) and the flame retardant layer (4) are in contact with each other, the first finishing glue (2) is in contact with the side of the winding core (1) on the side facing the inner side of the winding core (1), and the second finishing glue (5) is coated with the flame retardant layer (4) on the side facing the inner side of the winding core (1).

4. A battery cell structure according to claim 3, characterized in that: The battery core structure further comprises a shell, the winding core (1) is arranged in the shell, and the sum of the radius of the winding core (1), the thickness of the heat-sensitive coating (3), the thickness of the flame retardant layer (4) and the thickness of the second finishing glue (5) is smaller than the radius of the shell.

5. A battery cell structure according to any one of claims 1 to 4, characterized in that: The diaphragm has a tail end, the tail end is located at the outermost circle of the winding core (1), and the first tail glue (2) is adhered to the side of the tail end facing the outer side of the winding core (1).

6. A battery cell structure according to claim 5, characterized in that: The number of winding turns of the tail end of the diaphragm is 1 to 2 turns, and the number of winding turns of the first tail end glue (2) is at least 1.

7. A battery cell structure according to any one of claims 1 to 4, characterized in that: The cross section of the winding core (1) is circular, oval or square.

8. A battery cell structure according to any one of claims 1 to 4, characterized in that: The flame retardant layer (4) is a gel-state structure.

9. A lithium-ion battery, characterized in that: The battery cell structure comprises the battery cell structure according to any one of claims 1 to 8.

10. An electrical device, characterized in that: Including the lithium ion battery according to claim 9.

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