Lithium ion battery

Abstract

This utility model relates to a lithium-ion battery, including a battery casing, a core, an insulating film, and a base plate. The battery casing has a receiving cavity, the core is disposed within the receiving cavity, and the base plate is disposed at the bottom of the receiving cavity, positioned between the core and the battery casing. The base plate has several protrusions located on the side of the base plate facing the core. A first through hole is provided on the base plate. The insulating film wraps around the outer surface of the core, and a second through hole is provided on the insulating film, located on the side of the insulating film facing the base plate. The second through hole is offset from the first through hole. This lithium-ion battery prevents powder falling from the core from conducting between the core and the battery casing through the first and second through holes, thus reducing the risk of short circuits. Furthermore, by providing the protrusions, even with the first and second through holes misaligned, the electrolyte can smoothly enter the second through hole through a first gap.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries, as a new type of energy source with high energy density, long cycle life, high operating voltage, no pollution, and fast charging and discharging speed, have been widely used in energy storage devices. In related technologies, a lithium-ion battery includes a battery casing and a core installed inside the casing. The core is wrapped with an insulating film for insulation protection. A base plate is provided between the bottom of the core and the battery casing, which also serves as an insulating barrier. Both the base plate and the insulating film have through holes to allow the electrolyte inside the battery casing to enter the core. However, during the operation of a lithium-ion battery, when the electrodes in the core are subjected to external pressure or vibration, electrode powder may fall off. When the powder particles fall into the through holes, they can cause blockage, affecting the normal diffusion of the electrolyte. Furthermore, the powder particles falling into the through holes can also create a connection between the core and the battery casing, potentially leading to a short circuit. Utility Model Content

[0003] The purpose of this invention is to provide a lithium-ion battery that ensures the electrolyte diffuses smoothly from the battery casing into the core, thus avoiding the risk of short circuit.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A lithium-ion battery is provided, comprising a battery casing, a winding core, an insulating film, and a base plate. The battery casing has a receiving cavity, the winding core is disposed within the receiving cavity, and the base plate is disposed at the bottom of the receiving cavity, with the base plate located between the winding core and the battery casing. The base plate has a plurality of protrusions located on the side of the base plate facing the winding core. The base plate has a first through hole. The insulating film wraps around the outer surface of the winding core, and the insulating film has a second through hole located on the side of the insulating film facing the base plate. The second through hole is offset from the first through hole.

[0006] Furthermore, the insulating film is provided with a plurality of second through holes at intervals, the diameter of the second through holes being D2, 0.2mm≤D2≤1mm.

[0007] Furthermore, the spacing between two adjacent second through holes is D3, where D3 = 2D2 ~ 3D2.

[0008] Furthermore, the number of the first through holes is less than the number of the second through holes.

[0009] Furthermore, there are two first through holes, which are respectively disposed at both ends of the base plate along its length direction. The minimum distance between the first through holes and the ends of the base plate along its length direction is L1, and the length dimension of the base plate is L0, where L1 / L0 = 1 / 9 to 1 / 8.

[0010] Furthermore, the diameter of the first through hole is D1, where 0.2mm ≤ D1 ≤ 2mm.

[0011] Furthermore, the surface of the protrusion is spherical or curved.

[0012] Furthermore, the surface of the protrusion is spherical, and the diameter of the protrusion is D4, where 0 < D4 ≤ 0.3 mm.

[0013] Furthermore, the height of the protrusion is smaller than the diameter of the protrusion.

[0014] Furthermore, the base plate has several protrusions on both sides along its thickness direction.

[0015] The beneficial effects of this invention are as follows: By staggering the first and second through holes, powder falling from the core can be prevented from connecting the core to the battery casing through the first and second through holes, thus reducing the risk of short circuits. Furthermore, by providing the protrusions, a first gap is created between the base plate and the insulating film. Even with the first and second through holes staggered, the electrolyte can smoothly enter the second through hole through the first gap. Simultaneously, even if some of the second through holes are blocked by powder, the electrolyte can still flow into the core along the path of the first through hole, the first gap, and the unblocked second through hole, ensuring normal electrolyte diffusion. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a lithium-ion battery according to an embodiment of the present invention.

[0017] Figure 2 This is a partial cross-sectional view of a lithium-ion battery according to an embodiment of the present invention.

[0018] Figure 3 This is a partial cross-sectional view of a lithium-ion battery according to another embodiment of the present invention.

[0019] Figure 4 This is a partial cross-sectional view of a lithium-ion battery according to another embodiment of the present invention.

[0020] In the picture:

[0021] 1. Base plate; 11. Support plate; 12. Protrusion; 13. First through hole; 14. Enclosure plate; 2. Insulating film; 21. Cavity; 22. Second through hole; 3. Battery casing; 31. Receiving cavity; 32. Terminal post; 4. Core; 5. First gap; 6. Second gap. Detailed Implementation

[0022] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 and Figure 2 As shown, this embodiment provides a lithium-ion battery, including a battery casing 3, a core 4, an insulating film 2, and a base plate 1. The battery casing 3 is a square casing, typically made of aluminum or steel. The battery casing 3 has a hollow structure with an internal cavity 31. A terminal post 32 is provided on the top of the battery casing 3, for electrical connection to an external power source or external electrical equipment. The core 4 is used to generate an electrochemical reaction; the core 4 is disposed within the cavity 31 and electrically connected to the terminal post 32. The insulating film 2 provides insulation and isolation for the core 4, wrapping around its outer surface. The inner side of the insulating film 2 forms the cavity 21 for accommodating the core 4. The base plate 1 is made of insulating material and provides support and insulation for the core 4. The base plate 1 is located at the bottom of the cavity 31, between the core 4 and the battery casing 3. It should be noted that, since the insulating film 2 wraps around the outer surface of the core 4, one side of the base plate 1 in the thickness direction (Z direction in the figure) contacts the battery casing 3, and the other side contacts the insulating film 2. A gap exists between the core 4 and the sidewall of the battery casing 3, and this gap is filled with electrolyte. A first through hole 13 is provided on the base plate 1, penetrating both sides of the base plate 1 in the thickness direction, allowing electrolyte to flow through. Several protrusions 12 are provided on the side of the base plate 1 facing the core 4; that is, the protrusions 12 are located on the side of the base plate 1 facing the core 4, and the top of the protrusions 12 abuts against the insulating film 2. Under the support of the protrusions 12, a first gap 5 for electrolyte flow is formed between the base plate 1 and the insulating film 2. A second through hole 22 is provided on the side wall of the insulating film 2 facing the base plate 1. That is, the second through hole 22 is located on the surface of the insulating film 2 facing the base plate 1, and the second through hole 22 penetrates both sides of the insulating film 2 in the thickness direction, allowing the electrolyte to flow through. The electrolyte in the receiving cavity 31 can enter the core 4 in sequence through the first through hole 13, the first gap 5, and the second through hole 22 to maintain the core 4 in a state of being wetted by the electrolyte. The first through hole 13 and the second through hole 22 are staggered, that is, the projection of the second through hole 22 on the base plate 1 is spaced apart from the first through hole 13.

[0024] Understandably, the base plate 1 is freely placed at the bottom of the receiving cavity 31, and the two are not completely tightly fitted together. Therefore, the electrolyte in the receiving cavity 31 can enter the first through hole 13 through the tiny gap between the base plate 1 and the battery casing 3, thereby allowing the electrolyte to flow towards the winding core 4. By staggering the first through hole 13 and the second through hole 22, powder falling from the winding core 4 can be prevented from conducting between the winding core 4 and the battery casing 3 through the first through hole 13 and the second through hole 22, thus reducing the risk of short circuit. Furthermore, by providing the protrusion 12, a first gap 5 is created between the base plate 1 and the insulating film 2. Even with the staggered first through hole 13 and the second through hole 22, the electrolyte can smoothly enter the second through hole 22 through the first gap 5. At the same time, even if part of the second through hole 22 is blocked by powder, the electrolyte can still flow into the winding core 4 along the path of the first through hole 13, the first gap 5, and the unblocked second through hole 22, ensuring normal diffusion of the electrolyte.

[0025] Specifically, the base plate 1 includes a support plate 11 and a protrusion 12 formed on the support plate 11. The support plate 11 has a flat structure, and the support plate 11 and the protrusion 12 are integrally injection molded. The function of the protrusion 12 is to create a gap between the support plate 11 and the insulating film 2. Therefore, the protrusion 12 can be of any shape, such as spherical, hemispherical, square, cylindrical, etc. The end of the protrusion 12 facing away from the support plate 11 is the top of the protrusion 12, and the top of the protrusion 12 abuts against the insulating film 2, forming a first gap 5 between the support plate 11 and the insulating film 2. As one preferred embodiment, the surface of the protrusion 12 is spherical or curved to avoid the protrusion 12 puncturing the insulating film 2.

[0026] Specifically, the insulating film 2 has a plurality of second through holes 22 spaced apart. The insulating film 2 is attached to the surface of the core 4, that is, the second through holes 22 are located at the bottom of the core 4. The diameter of the second through hole 22 is D2, 0.2mm≤D2≤1mm. A sufficient number of second through holes 22 are required on the insulating film 2 to ensure that the electrolyte can smoothly enter the core 4. Since the particle size of the powder is generally greater than 1mm, the diameter of the second through hole 22 is less than 1mm, which helps to prevent the powder from entering the second through hole 22 and falling into the first gap 5. In this embodiment, the value range of the diameter D2 of the second through hole 22 includes, but is not limited to, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm and 1mm.

[0027] Specifically, the spacing between two adjacent second through holes 22 is D3, where D3 = 2D2 to 3D2. In this embodiment, the multiple second through holes 22 are arranged in an array, and the spacing D3 between two adjacent second through holes 22 is the minimum value of the spacing between two adjacent second through holes 22 in the same horizontal row and the spacing between two adjacent second through holes 22 in the same vertical column. By setting the spacing of the second through holes 22 to 2 to 3 times the diameter of the second through holes 22, a sufficient number of second through holes 22 can be arranged on the insulating film 2 to ensure the penetration efficiency of the electrolyte on the insulating film 2.

[0028] Specifically, the number of first through holes 13 is less than the number of second through holes 22. The relatively smaller number of first through holes 13 reduces the probability of powder falling into them, thus lowering the risk of short circuits. As a preferred embodiment, two first through holes 13 are provided, each located at one end of the base plate 1 along its length (X direction in the diagram). Since the electrolyte is mainly contained in the side area of ​​the core 4, placing the first through holes 13 at the ends of the base plate 1 helps reduce the flow path of the electrolyte into the first through holes 13. The distance between the first through hole 13 and the corresponding end of the base plate 1 along its length is L1, where L1 is the minimum distance between the first through hole 13 and the end of the base plate 1. The length of the base plate 1 is L0, and L1 / L0 = 1 / 9 to 1 / 8. Of course, in practical applications, the position of the first through hole 13 on the base plate 1 can be flexibly selected according to the specific structure of the base plate 1, so as to facilitate the efficient flow of electrolyte in the receiving cavity 31 into the first through hole 13. The diameter of the first through hole 13 is D1, 0.2mm≤D1≤2mm. It can be understood that the number of first through holes 13 is relatively small, therefore, the diameter of the first through hole 13 is set to be larger than that of the second through hole 22 to ensure the flow efficiency of electrolyte. In this embodiment, the value range of the diameter D1 of the first through hole 13 includes, but is not limited to, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm.

[0029] Specifically, the surface of the protrusion 12 is spherical, and the diameter of the protrusion 12 is D4, where 0 < D4 ≤ 0.3 mm. It is understood that under the gravity of the core 4, the insulating film 2 will partially cover the protrusion 12. The contact area between the protrusion 12 and the insulating film 2 is located between several adjacent second through holes 22. Therefore, the size of the protrusion 12 is smaller than the distance D3 between two adjacent second through holes 22. In this embodiment, the diameter D4 of the protrusion 12 can range from, but is not limited to, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, and 0.3 mm.

[0030] Specifically, the height of the protrusion 12 is smaller than its diameter D4. This structure helps to reduce the width of the first gap 5, that is, to reduce the distance between the support plate 11 and the insulating film 2. Since the flow of electrolyte relies on capillary action between the support plate 11 and the insulating film 2, in practical applications, the height of the protrusion 12 should be reasonably selected according to the characteristics of the electrolyte to promote smooth flow of electrolyte within the first gap 5.

[0031] In another embodiment, such as Figure 3 As shown, the bottom support plate 1 has several protrusions 12 on both sides along its thickness direction. Specifically, the side of the support plate 11 facing the winding core 4 has several protrusions 12, and the side of the support plate 11 away from the winding core 4 also has several protrusions 12. This structure creates a second gap 6 between the support plate 11 and the bottom of the receiving cavity 31, facilitating the flow of electrolyte into the second gap 6 before entering the first through hole 13. This structure avoids reducing the electrolyte flow efficiency due to excessively tight contact between the support plate 11 and the bottom of the battery casing 3.

[0032] In another embodiment, such as Figure 4 As shown, the base plate 1 includes a support plate 11 and a surrounding plate 14 arranged around the periphery of the support plate 11, forming a groove between the support plate 11 and the surrounding plate 14. The bottom end of the winding core 4 is inserted into the groove. Several protrusions 12 are provided on the groove wall, and the protrusions 12 contact the insulating film 2. This structure allows the electrolyte to flow directly downwards into the groove through the side area of ​​the winding core 4, and then flow from the groove to the second through hole 22. This avoids reducing the electrolyte flow efficiency due to the support plate 11 being too tightly attached to the bottom of the battery casing 3.

[0033] The beneficial effects of this embodiment are as follows: By staggering the first through hole 13 and the second through hole 22, powder falling from the core 4 can be prevented from connecting the core 4 to the battery casing 3 through the first through hole 13 and the second through hole 22, thereby reducing the risk of short circuit. Furthermore, by providing the protrusion 12, a first gap 5 is created between the base plate 1 and the insulating film 2. Even with the first through hole 13 and the second through hole 22 staggered, the electrolyte can smoothly enter the second through hole 22 through the first gap 5. Simultaneously, even if some of the second through hole 22 is blocked by powder, the electrolyte can still flow into the core 4 along the path of the first through hole 13, the first gap 5, and the unblocked second through hole 22, ensuring normal diffusion of the electrolyte.

[0034] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A lithium-ion battery, characterized by, The device includes a battery casing, a winding core, an insulating film, and a base plate. The battery casing has a receiving cavity, the winding core is disposed within the receiving cavity, and the base plate is disposed at the bottom of the receiving cavity, with the base plate located between the winding core and the battery casing. The base plate has several protrusions located on the side of the base plate facing the winding core. The base plate has a first through hole. The insulating film wraps around the outer surface of the winding core, and the insulating film has a second through hole located on the surface of the insulating film facing the base plate. The second through hole is offset from the first through hole.

2. The lithium-ion battery of claim 1, wherein, The insulating film is provided with a plurality of second through holes spaced apart, the diameter of the second through holes being D2, 0.2mm≤D2≤1mm.

3. The lithium-ion battery of claim 2, wherein, The distance between two adjacent second through holes is D3, where D3 = 2D2 ~ 3D2.

4. The lithium-ion battery of claim 2, wherein, The number of the first through holes is less than the number of the second through holes.

5. The lithium-ion battery of claim 4, wherein, There are two first through holes, which are respectively disposed at both ends of the base plate along its length direction. The minimum distance between the first through holes and the ends of the base plate along its length direction is L1. The length dimension of the base plate is L0, and L1 / L0 = 1 / 9 to 1 / 8.

6. The lithium-ion battery of claim 1, wherein, The diameter of the first through hole is D1, where 0.2mm ≤ D1 ≤ 2mm.

7. The lithium-ion battery of claim 1, wherein, The surface of the protrusion is spherical or curved.

8. The lithium-ion battery of claim 1, wherein, The surface of the protrusion is spherical, and the diameter of the protrusion is D4, where 0 < D4 ≤ 0.3 mm.

9. The lithium-ion battery of claim 8, wherein, The height of the protrusion is smaller than the diameter of the protrusion.

10. The lithium-ion battery according to any one of claims 1 to 9, characterized in that, The base plate has several protrusions on both sides along its thickness direction.

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