Structure for improving corrosion resistance of battery

Abstract

The utility model relates to a structure for improving the corrosion resistance of a battery, which comprises a bottom support, a first through hole and a second through hole, the Mylar film comprises a bearing film fixed to the top of the bottom support body, a second through hole penetrating through the bearing film and a runner arranged between the bottom support body and the bearing film; the first through hole and the second through hole are staggered, and the first through hole and the second through hole are communicated through a flow channel. According to the structure for improving the corrosion resistance of the battery, a one-to-one correspondence design of the Mylar film and the bottom support hole is changed into a staggered design, so that electron and ion channel paths for corroding the aluminum shell of the battery are greatly increased, the possibility that the pole piece is in contact with the aluminum shell after powder falls off is prevented by the design, the probability of corrosion and liquid leakage of the battery is reduced, and the service life of the battery is prolonged. And the safety performance of the battery is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium batteries, and in particular relates to a structure for improving the corrosion resistance of batteries. Background Art

[0002] Existing lithium batteries, especially square lithium batteries, mainly include shell, core, bottom bracket and Mylar film and other parts. The core is wrapped with Mylar film to achieve isolation from the shell, and electrolyte is injected between the shell and the Mylar film. The bottom bracket is welded to the Mylar film at the bottom of the core and is provided with a through hole. The electrolyte can penetrate into the core through the through hole, so that the electrolyte flows from the negative electrode to the positive electrode, achieving the effect of lithium battery charging and discharging, which not only ensures the insulation between the core and the aluminum shell, but also ensures the good wettability of the core after the electrolyte enters the shell.

[0003] However, with this design, the probability of the electrode expanding and losing powder will increase as the number of charge and discharge cycles of the battery increases. Since the negative electrode expands and loses powder and comes into contact with the aluminum shell through the through-hole, the aluminum shell of the battery will corrode. If the corrosion is severe, leakage will occur during the use of the battery, which poses a great safety hazard to the battery. Utility Model Content

[0004] The utility model provides a structure for improving the corrosion resistance of the battery, and changes the Mylar film and the bottom support hole from a one-to-one corresponding design to a staggered design, which greatly prevents the aluminum shell from being corroded and leaking due to pole piece expansion and powder loss, and reduces safety hazards.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a structure for improving the corrosion resistance of the battery, which comprises:

[0006] A base, the base comprising a base body and a first through hole penetrating the base body;

[0007] Mylar film, the Mylar film comprising a carrier film fixed on the top of the base body, a second through hole penetrating the carrier film, and a flow channel arranged between the base body and the carrier film;

[0008] The first through hole is staggered with the second through hole, and the first through hole and the second through hole are connected through a flow channel.

[0009] Optimally, the Mylar film also includes a first folding film integrally connected to both sides of the carrier film and arranged oppositely, and a second folding film integrally connected to both sides of the first folding film and arranged oppositely. After folding, the first folding film and the second folding film form a core cavity with the carrier film.

[0010] Optimally, the Mylar film further comprises inner folding films integrally connected to both sides of the carrier film and arranged opposite to each other, and the inner folding films are located on the inner side of the second folding film after being folded.

[0011] Optimally, the Mylar film further comprises inner tapered portions arranged on both sides of the inner folded film and an outer tapered portion arranged on a side of the second folded film close to the inner folded film.

[0012] Optimally, the width of the second folding film is smaller than the width of the carrier film, and the width of the second folding film is greater than half of the width of the carrier film.

[0013] Optimally, the base also includes a first overflow hole penetrating the base body, and a diameter of the first overflow hole is greater than a diameter of the first through hole.

[0014] Optimally, the Mylar film further includes a second overflow hole penetrating the carrier film, and a diameter of the second overflow hole is larger than a diameter of the second through hole.

[0015] Optimally, after the carrying film is fixed to the top of the base body, the first overflow hole overlaps with the second overflow hole.

[0016] Optimally, the diameter of the first through hole is equal to the diameter of the second through hole.

[0017] Optimally, the diameter of the first overflow hole is equal to the diameter of the second overflow hole.

[0018] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0019] The utility model improves the corrosion resistance of the battery by changing the Mylar film and the bottom support hole from a one-to-one corresponding design to a staggered design, which greatly increases the electron and ion channel paths that cause corrosion to the battery aluminum shell. Moreover, this design itself prevents the possibility of the pole piece from contacting the aluminum shell after powder falls off, reduces the probability of corrosion and leakage of the battery, and greatly improves the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the bottom bracket of the utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the Mylar film of the utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the base and the Mylar film after being laminated to each other;

[0023] Figure 4 It is the traditional ion path trajectory diagram;

[0024] Figure 5 It is the existing ion path trajectory diagram of the utility model;

[0025] Description of reference numerals:

[0026] 1. Bottom bracket; 11. Bottom bracket body; 12. First through hole; 13. First overflow hole;

[0027] 2. Mylar film; 21. Carrying film; 22. First folding film; 23. Second folding film; 24. Inner folding film; 25. Inner tapered portion; 26. Outer tapered portion; 27. Second through hole; 28. Second overflow hole. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the embodiments shown in the accompanying drawings.

[0029] The utility model discloses a structure for improving the corrosion resistance of a battery, which is composed of a bottom support 1 and a Mylar film 2.

[0030] The core is wrapped with Mylar film 2 to achieve isolation from the shell. When the core is loaded into the battery shell, it can prevent the core from being scratched when loaded into the battery shell, and it can also play an insulating role to prevent the core and the metal shell of the battery from directly contacting each other and causing safety accidents. Electrolyte is injected between the shell and the Mylar film 2. The base 1 is welded to the Mylar film 2 at the bottom of the core and is provided with a through hole. The electrolyte can penetrate into the core through the through hole, so that the electrolyte flows from the negative electrode to the positive electrode, achieving the effect of charging and discharging the lithium battery.

[0031] like Figure 1 , which is a schematic diagram of the structure of the base 1, the base 1 comprises a base body 11 and a first through hole 12. The base body 11 is made of PP or PET, and the base 1 is rectangular, having two long sides and two short sides arranged oppositely.

[0032] The base body 11 is provided with a plurality of first through holes 12 in a rectangular array, and the first through holes 12 penetrate the base body 11. After the electrolyte is injected between the shell and the Mylar film 2, the electrolyte flows and penetrates into the winding core through the first through holes 12 on the base 1 and the second through holes 27 on the Mylar film 2, so that the electrolyte flows from the negative electrode to the positive electrode, achieving the effect of charging and discharging the lithium battery.

[0033] The Mylar film 2 is fixed on the base 1 and is used to cover the core. Figure 2As shown, the Mylar film 2 includes a carrier film 21, a first folding film 22, a second folding film 23, an inner folding film 24, an inner tapered portion 25, an outer tapered portion 26, and a second through hole 27. The carrier film 21 is also rectangular, having two long sides and two short sides arranged opposite to each other, and the size of the carrier film 21 matches the size of the base body 11 to improve the effect of the base 1 supporting the Mylar film 2.

[0034] The first folding film 22 has two pieces, which are integrally connected to the long side of the carrier film 21 and arranged opposite to each other. There is a bending line between the first folding film 22 and the long side of the carrier film 21. The first folding film 22 can be bent upward along the bending line to be perpendicular to the carrier film 21 to facilitate the subsequent insertion of the roll core.

[0035] The second folding film 23 is integrally connected to both sides of the first folding film 22 and arranged oppositely, and a bending line is provided between the second folding film 23 and the first folding film 22 . The second folding film 23 can be bent upward along the bending line to be perpendicular to the first folding film 22 .

[0036] like Figure 2 As shown, there are two first folding films 22 and four second folding films 23 on a Mylar film 2. According to the folding method of a cuboid, by folding the first folding films 22 and the second folding films 23, a cuboid with a roll core cavity can be folded. The top of the cuboid is open to facilitate the insertion of the roll core. The carrier film 21 is the lower surface A of the cuboid, the two first folding films 22 are the two opposite side surfaces B of the cuboid, and the second folding films 23 are the other two opposite side surfaces C of the cuboid.

[0037] exist Figure 2 In the viewing angle shown, the two second folding films 23 above the carrier film 21 are folded to form one side surface C, and the two second folding films 23 below the carrier film 21 are folded to form the other side surface C.

[0038] After folding, the folded part is fixed by hot melt. The width of the second folding film 23 is greater than half of the width of the carrier film 21. When the two second folding films 23 are folded to form the side C of the cuboid, it is ensured that there is an overlapping part between the two. On the one hand, it is convenient for hot melt fixing, and on the other hand, it is avoided that there are gaps in the folding and the internal winding core is avoided. The width of the second folding film 23 is smaller than the width of the carrier film 21. After folding, the second folding film 23 is prevented from protruding from the side C of the cuboid to avoid affecting the subsequent assembly.

[0039] The inner folding film 24 has two pieces, which are integrally connected to the two sides of the carrier film 21 and arranged opposite to each other. There is also a bending line between the inner folding film 24 and the carrier film 21. The inner folding film 24 can be bent upward along the bending line to be perpendicular to the carrier film 21. After the inner folding film 24, the first folding film 22 and the second folding film 23 are folded, the three are fixed by hot melting.

[0040] The inner folding film 24 is located on the inner side of the second folding film 23. Since the inner folding film 24 is integrally connected to both sides of the carrier film 21, after the inner folding film 24 is folded upward, no hot melt seam will appear at the folding position. The integrated inner folding film 24 can improve the structural strength of the carrier film 21. After the second folding film 23 is folded, it is covered on the outer surface of the inner folding film 24. After hot melting, the second folding film 23 and the inner folding film 24 are fixed, and the structural strength at the folding corner is higher.

[0041] like Figure 2 As shown, inner tapered portions 25 are provided on both sides of the inner folded film 24, that is, the inner folded film 24 and the inner tapered portions 25 form an isosceles trapezoidal shape. With the two waists, when the inner folded film 24 is bent inward, the inner folded film 24 and the inner surface of the first folded film 22 will not contact and rub, thereby avoiding scratches on the inner side of the first folded film 22 and affecting the life of the overall structure.

[0042] like Figure 2 As shown, the second folding film 23 is provided with an outer tapered portion 26 on one side close to the inner folding film 24, and the second folding film 23 and the outer tapered portion 26 form a right-angled trapezoid. The provision of the outer tapered portion 26 facilitates the folding of the second folding film 23, and also makes it easier to perform hot-melt treatment after folding.

[0043] The carrier film 21 is provided with a plurality of second through holes 27 in a rectangular array, and the second through holes 27 penetrate the carrier film 21. After the electrolyte is injected between the shell and the Mylar film 2, the electrolyte flows and penetrates into the winding core through the first through hole 12 on the base 1 and the second through hole 27 on the Mylar film 2, so that the electrolyte flows from the negative electrode to the positive electrode, achieving the effect of charging and discharging the lithium battery.

[0044] The carrier film 21 is fixed on the top of the base body 11, and a flow channel is provided between the carrier film 21 and the base body 11, and the first through hole 12 and the second through hole 27 are connected through the flow channel to facilitate the flow of the electrolyte. In specific implementation, the two long sides of the carrier film 21 can be fixed on the two long sides of the base body 11, or the two short sides of the carrier film 21 can be fixed on the two short sides of the base body 11, so as to avoid the carrier film 21 and the base body 11 being completely close to each other, so that the first through hole 12 and the second through hole 27 cannot be connected.

[0045] The diameters of the first through hole 12 and the second through hole 27 are the same, and the projection of the second through hole 27 on the base body 11 is staggered from the first through hole 12. The electron channel and the ion channel are connected through the Mylar membrane holes and the base holes. Figure 4 As shown, the holes in the traditional Mylar membrane correspond one to one with the holes in the bottom support. As the negative electrode expands and powder falls off, it comes into direct contact with the aluminum shell through the through holes. At this time, the aluminum shell of the battery will corrode. If the corrosion is severe, leakage will occur during the use of the battery, which poses a great safety hazard to the battery.

[0046] like Figure 5 As shown, the staggered design of the first through hole 12 and the second through hole 27 greatly increases the paths of the electron channel and the ion channel, and prevents the falling powder of the electrode from contacting the aluminum shell (the electrode falls through the second through hole 27 and falls on the bottom bracket 1, and will not fall on the aluminum shell through the first through hole 12), thereby solving the corrosion and leakage of the aluminum shell due to powder falling, and greatly improving the safety performance of the battery.

[0047] Since the first folding film 22, the second folding film 23 and the inner folding film 24 are folded to form a rectangular shape with the carrier film 21, the electrolyte is injected between the shell and the Mylar film 2, and the electrolyte at the long side of the base 1 flows relatively fast, while more electrolyte will gather at the short side of the base 1. Therefore, the base body 11 is provided with a first overflow hole 13, and the diameter of the first overflow hole 13 is greater than the diameter of the first through hole 12. The carrier film 21 is provided with a second overflow hole 28, and the diameter of the second overflow hole 28 is greater than the diameter of the second through hole 27.

[0048] When the Mylar film 2 is fixed on the base 1, the second overflow hole 28 overlaps with the first overflow hole 13, and the diameters of the two are the same, so as to avoid the electrolyte from gathering at the short side (the first through hole 12 and the second through hole 27 are still in a staggered distribution).

[0049] The utility model improves the corrosion resistance of the battery by changing the Mylar film and the bottom support hole from a one-to-one corresponding design to a staggered design, which greatly increases the electron and ion channel paths of corrosion. Moreover, this design itself prevents the possibility of the pole piece from contacting the aluminum shell after powder falls off, reduces the probability of corrosion and leakage of the battery, and greatly improves the safety performance of the battery.

[0050] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A structure for improving the corrosion resistance of a battery, characterized in that: include: A base (1), the base (1) comprising a base body (11) and a first through hole (12) penetrating the base body (11); A Mylar film (2), the Mylar film (2) comprising a carrier film (21) fixed on the top of the base body (11), a second through hole (27) penetrating the carrier film (21), and a flow channel arranged between the base body (11) and the carrier film (21); The first through hole (12) and the second through hole (27) are staggered, and the first through hole (12) and the second through hole (27) are connected through a flow channel.

2. A structure for improving the corrosion resistance of a battery according to claim 1, characterized in that: The Mylar film (2) further comprises a first folding film (22) integrally connected to both sides of the carrier film (21) and arranged opposite to each other, and a second folding film (23) integrally connected to both sides of the first folding film (22) and arranged opposite to each other, wherein the first folding film (22) and the second folding film (23) are folded to form a winding core cavity together with the carrier film (21).

3. A structure for improving the corrosion resistance of a battery according to claim 2, characterized in that: The Mylar film (2) further comprises inner folding films (24) integrally connected to both sides of the carrier film (21) and arranged opposite to each other, and the inner folding films (24) are located on the inner side of the second folding film (23) after being folded.

4. A structure for improving the corrosion resistance of a battery according to claim 3, characterized in that: The Mylar film (2) further comprises inner tapered portions (25) arranged on both sides of the inner folded film (24) and an outer tapered portion (26) arranged on one side of the second folded film (23) close to the inner folded film (24).

5. The structure for improving the corrosion resistance of a battery according to claim 2, characterized in that: The width of the second folding film (23) is smaller than the width of the carrying film (21), and the width of the second folding film (23) is greater than half the width of the carrying film (21).

6. The structure for improving the corrosion resistance of a battery according to claim 1, characterized in that: The base (1) further comprises a first overflow hole (13) penetrating the base body (11), wherein the diameter of the first overflow hole (13) is greater than the diameter of the first through hole (12).

7. A structure for improving the corrosion resistance of a battery according to claim 6, characterized in that: The Mylar film (2) further comprises a second overflow hole (28) penetrating the carrier film (21), wherein the diameter of the second overflow hole (28) is greater than the diameter of the second through hole (27).

8. The structure for improving the corrosion resistance of a battery according to claim 7, characterized in that: When the carrying film (21) is fixed on the top of the base body (11), the first overflow hole (13) and the second overflow hole (28) overlap.

9. The structure for improving the corrosion resistance of a battery according to claim 1, characterized in that: The diameter of the first through hole (12) is equal to the diameter of the second through hole (27).

10. The structure for improving the corrosion resistance of a battery according to claim 7, characterized in that: The diameter of the first overflow hole (13) is equal to the diameter of the second overflow hole (28).

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