Square winding lithium battery

Abstract

The utility model discloses a square winding lithium battery which comprises a battery outer shell, the battery outer shell is an aluminum shell, an inner sealing shell is arranged in the battery outer shell, an inner cavity is formed between the battery outer shell and the inner sealing shell, a plurality of buffer balls are filled in the inner cavity, and the interior of each buffer ball is designed to be of a hollow structure. A wound positive plate is arranged in the inner sealing shell, a diaphragm is wound on the inner side of the positive plate, a negative plate is wound on the inner side of the diaphragm, the positive plate, the diaphragm and the negative plate jointly form a lithium battery cell, the positive plate is a porous aluminum foil, and the porosity of the porous aluminum foil ranges from 20% to 50%. Therefore, the energy density of the wound lithium battery can be effectively improved, the wound lithium battery has an actual adaptation effect of high energy density, the performance of the battery can be further optimized, the interface resistance can be effectively reduced through the coated conductive polymer layer, and the use effect of the battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, specifically to a square wound lithium battery. Background Technology

[0002] Lithium-ion batteries have advantages such as high operating voltage, high specific energy, long cycle life, and no environmental pollution. They are widely used not only in mobile communication devices and portable electronic devices, but also in large and medium-sized electric equipment such as electric vehicles, electric bicycles, and power tools. They are currently the main development direction of major battery manufacturers.

[0003] Lithium-ion batteries mainly include square, round, and polymer types, among which the winding of the cells has a very important impact on the performance and safety of lithium-ion batteries.

[0004] The prior art discloses a novel square wound lithium battery with application number CN201020698217.1, comprising a battery cell (1) formed by sequentially stacking and winding a negative electrode (1.1), a separator (1.3), and a positive electrode (1.2). The battery cell (1) has a winding needle hole (1.4) in the middle, and a gasket (1.5) with acid and alkali resistance and insulation and irreversible deformation is provided inside the winding needle hole (1.4). This square wound lithium battery can prevent breakage at the arc-shaped corners of the inner electrode of the battery cell and damage to the separator.

[0005] Based on the search of the aforementioned patents and the findings of existing battery usage, it was discovered that the energy density of the aforementioned batteries is relatively low when used, which prevents further optimization of battery performance. At the same time, the protection performance is poor, and the cells are easily damaged by external forces, affecting the service life. Utility Model Content

[0006] The purpose of this invention is to provide a square wound lithium battery to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a square wound lithium battery, comprising a battery casing, the battery casing being an aluminum casing, an inner sealing shell being disposed inside the battery casing, an inner cavity being disposed between the battery casing and the inner sealing shell, the inner cavity being filled with a plurality of buffer balls, the buffer balls having a hollow structure design, a wound positive electrode sheet being disposed inside the inner sealing shell, a separator being wound on the inner side of the positive electrode sheet, a negative electrode sheet being wound on the inner side of the separator, the positive electrode sheet, the separator, and the negative electrode sheet together forming a lithium battery cell, the positive electrode sheet being a porous aluminum foil with a porosity between 20% and 50%, and a conductive polymer layer being coated on the surface of the positive electrode sheet, the coating area of ​​the conductive polymer layer being not less than two-thirds of the total area of ​​the positive electrode sheet.

[0008] Preferably, the buffer ball is made of elastic silicone material, and the interior of the buffer ball is filled with an inert gas, namely helium.

[0009] Preferably, the winding angle of the positive electrode, the separator, and the negative electrode is between 10° and 45°.

[0010] Preferably, the conductive polymer layer is a coated conductive polymer, and the thickness of the conductive polymer layer is between 5-20 μm.

[0011] Preferably, the space between the inner sealing shell and the lithium battery cell is filled with electrolyte.

[0012] Preferably, a top cover is fixedly installed on the top of the battery casing, and a positive terminal post and a negative terminal post are respectively installed on both sides of the upper surface of the top cover.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This invention designs and optimizes the structure of the wound positive electrode sheet, which effectively reduces the interface resistance. At the same time, by coating it with a large-area conductive polymer layer, the energy density of the wound lithium battery can be effectively improved, resulting in a high energy density and further optimizing battery performance. The conductive polymer layer effectively reduces the interface resistance and improves the battery's performance.

[0015] Meanwhile, the winding angles of the positive electrode, separator, and negative electrode are between 10° and 45°. This structural design can effectively avoid the problem of excessive stress concentration caused by right-angle bending, effectively reduce internal stress, reduce the risk of battery short circuit, and improve battery safety.

[0016] Furthermore, the elastically deformable buffer ball can effectively buffer and resist external pressure, thereby better protecting the internal battery structure from damage. It has a certain buffering protection effect, improves the buffering protection performance of the internal battery structure, avoids external forces acting directly on the internal cells, improves the overall lifespan of lithium batteries, and is more practical.

[0017] Finally, the buffer ball of this invention is filled with helium. With this structural design, when an open flame appears in the internal battery cell, the buffer ball will rupture due to heat. At this time, the helium filled inside the buffer ball will be released. The released helium can play a certain role in flame retardancy, effectively suppressing the spread of flames and providing a certain flame retardant time for emergency handling. This improves the safety of lithium battery structure and makes the buffer ball not only have the buffering function of a sphere, but also the released inert gas has a good flame retardant effect. It has multiple functions and improves the overall safety of battery use. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external three-dimensional structure of the lithium battery according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the internal structure of the battery casing according to an embodiment of the present utility model;

[0020] Figure 3 This is a schematic diagram of the internal planar structure of the battery casing according to an embodiment of the present invention.

[0021] In the diagram: 1. Battery outer casing; 2. Inner sealing shell; 3. Inner cavity; 4. Buffer ball; 5. Positive electrode plate; 6. Separator; 7. Negative electrode plate; 8. Electrolyte; 9. Top cover; 10. Positive electrode post; 11. Negative electrode post. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] Please see Figure 1-3The present invention provides an embodiment of a square wound lithium battery, including a battery casing 1, which is an aluminum casing. This improves the structural strength of the external casing of the lithium battery, enabling it to effectively resist external impacts and providing better structural reinforcement and protection.

[0026] The battery housing 1 has an inner sealing shell 2 inside, and an inner cavity 3 is provided between the battery housing 1 and the inner sealing shell 2. The inner cavity 3 is filled with a number of buffer balls 4, and the buffer balls 4 have a hollow structure design.

[0027] Among them, the buffer ball 4 is made of elastic silicone material, and the interior of the buffer ball 4 is filled with inert gas, which is helium.

[0028] With this structural design, when an external impact force causes an impact dent to the battery casing 1, the dented deformation area of ​​the battery casing 1 will squeeze the internal buffer ball 4. The buffer ball 4 will undergo a certain elastic deformation due to the external pressure. The elastically deformed buffer ball 4 can effectively buffer and resist the external pressure, thereby better protecting the internal battery structure from damage. It has a certain buffer protection effect, improves the buffer protection performance of the internal battery structure, avoids external forces acting directly on the internal cells, improves the overall service life of the lithium battery, and is more practical.

[0029] Meanwhile, the buffer ball 4 of this utility model is filled with helium. With this structural design, when an open flame appears in the internal battery cell, the buffer ball 4 will crack due to heat. At this time, the helium filled inside the buffer ball 4 will be discharged. The discharged helium can play a certain flame-retardant role, effectively suppressing the spread of flames and providing a certain flame-retardant time for emergency handling. This improves the safety of lithium battery structure. The buffer ball 4 not only has the buffering function of a sphere, but also the discharged inert gas has a good flame-retardant effect, which has the versatility of function and improves the overall safety of battery use.

[0030] Furthermore, the inner sealing shell 2 is provided with a wound positive electrode 5, a separator 6 is wound inside the positive electrode 5, and a negative electrode 7 is wound inside the separator 6. The positive electrode 5, the separator 6 and the negative electrode 7 together form a lithium battery cell. The space between the inner sealing shell 2 and the lithium battery cell is filled with electrolyte 8, which can ensure normal use.

[0031] The positive electrode 5 is a porous aluminum foil with a porosity between 20% and 50%. The surface of the positive electrode 5 is coated with a conductive polymer layer, and the coating area of ​​the conductive polymer layer is not less than two-thirds of the total area of ​​the positive electrode 5.

[0032] The positive electrode 5 with this structural design can effectively reduce the interface impedance. At the same time, by coating with a large area of ​​conductive polymer layer, the energy density of the wound lithium battery of this utility model can be effectively improved, and it has a high energy density practical adaptability effect, so that the battery performance can be further optimized.

[0033] It should be noted that the conductive polymer layer is a coated conductive polymer, which is polypyrrole. It has strong adhesion to the positive electrode 5 of aluminum foil. The thickness of the conductive polymer layer is between 5-20μm. The coated conductive polymer layer can effectively reduce the interface resistance and improve the performance of the battery.

[0034] In this embodiment, the winding angles of the positive electrode 5, the separator 6, and the negative electrode 7 are between 10° and 45°. This structural design can effectively avoid the problem of excessive stress concentration caused by right-angle bending, effectively reduce internal stress, reduce the risk of battery short circuit, and improve battery safety.

[0035] In this embodiment, in order to ensure the normal power connection and use of the lithium battery, a top cover 9 is fixedly installed on the top of the battery casing 1. A positive electrode post 10 and a negative electrode post 11 are respectively installed on both sides of the upper surface of the top cover 9. The positive electrode post 10 and the negative electrode post 11 are electrically connected to the internal lithium battery cell, thereby ensuring the normal power connection and use of the lithium battery.

[0036] Working principle: Users can use the square wound lithium battery of this utility model through conventional methods;

[0037] This utility model sets the positive electrode 5 as a porous aluminum foil with a porosity between 20% and 50%, and coats the surface of the positive electrode 5 with a conductive polymer layer, the coating area of ​​which is not less than two-thirds of the total area of ​​the positive electrode 5.

[0038] By designing and optimizing the structure of the positive electrode 5, the positive electrode 5 of this invention can effectively reduce the interface resistance. At the same time, by coating with a large area of ​​conductive polymer layer, the energy density of the wound lithium battery of this invention can be effectively improved, and it has a high energy density practical adaptability effect, so that the battery performance can be further optimized. The conductive polymer layer can effectively reduce the interface resistance and improve the battery's performance.

[0039] Meanwhile, the winding angles of the positive electrode 5, the separator 6, and the negative electrode 7 are between 10° and 45°. This structural design can effectively avoid the problem of excessive stress concentration caused by right-angle bending, effectively reduce internal stress, reduce the risk of battery short circuit, and improve battery safety.

[0040] Furthermore, when the lithium battery of this utility model is subjected to an external impact, causing the battery casing 1 to be dented, the dented deformation area of ​​the battery casing 1 will squeeze the internal buffer ball 4. The buffer ball 4 will undergo a certain elastic deformation due to the external pressure. The elastically deformed buffer ball 4 can effectively buffer and resist the external pressure, thereby better protecting the internal battery structure from damage. It has a certain buffer protection effect, improves the buffer protection performance of the internal structure of the battery, avoids the external force from acting directly on the internal cells, improves the overall service life of the lithium battery, and is more practical.

[0041] Meanwhile, the buffer ball 4 of this utility model is filled with helium. With this structural design, when an open flame appears in the internal battery cell, the buffer ball 4 will crack due to heat. At this time, the helium filled inside the buffer ball 4 will be discharged. The discharged helium can play a certain flame-retardant role, effectively suppressing the spread of flames and providing a certain flame-retardant time for emergency handling. This improves the safety of lithium battery structure. The buffer ball 4 not only has the buffering function of a sphere, but also the discharged inert gas has a good flame-retardant effect, which has the versatility of function and improves the overall safety of battery use.

[0042] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A square wound lithium battery comprising a battery outer housing (1), characterized in that, The battery casing (1) has an inner sealing shell (2) inside. An inner cavity (3) is provided between the battery casing (1) and the inner sealing shell (2). The inner cavity (3) is filled with several buffer balls (4). The buffer balls (4) have a hollow structure design. The inner sealing shell (2) has a wound positive electrode sheet (5). A separator (6) is wound on the inner side of the positive electrode sheet (5). A negative electrode sheet (7) is wound on the inner side of the separator (6). The positive electrode sheet (5), the separator (6) and the negative electrode sheet (7) together form a lithium battery cell. The positive electrode sheet (5) is a porous aluminum foil with a porosity between 20% and 50%. The surface of the positive electrode sheet (5) is coated with a conductive polymer layer. The coating area of ​​the conductive polymer layer is not less than two-thirds of the total area of ​​the positive electrode sheet (5).

2. The square-wound lithium battery of claim 1, wherein: The buffer ball (4) is made of elastic silicone material and is filled with an inert gas, which is helium. 3.The square-wound lithium battery of claim 1, wherein: The winding angles of the positive electrode (5), the separator (6), and the negative electrode (7) are between 10° and 45°. 4.The square-wound lithium battery of claim 1, wherein: The conductive polymer layer is a coated conductive polymer, and the thickness of the conductive polymer layer is between 5-20 μm.

5. The square-wound lithium battery of claim 1, wherein: The inner sealing shell (2) is filled with electrolyte (8) between itself and the lithium battery cell. 6.The square-wound lithium battery of claim 1, wherein: The battery casing (1) is an aluminum casing. 7.The square-wound lithium battery of claim 1, wherein: A top cover (9) is fixedly installed on the top of the battery casing (1), and a positive terminal post (10) and a negative terminal post (11) are respectively installed on both sides of the upper surface of the top cover (9).

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