Improved lithium battery structure

Abstract

The utility model discloses an improved lithium battery structure, which comprises a shell, a battery cell, a positive electrode end, a negative electrode end and the like, and is mainly characterized in that a negative electrode current collector of the negative electrode end is circumferentially welded in the shell through a surrounding edge, and a negative electrode bottom cover is circumferentially welded in the shell through an outer folding section of a folding edge; a caulking seam is formed between the inner folding section of the folding edge and the inner circumferential surface of the shell to sleeve the surrounding edge, so that the whole structure is simpler, and the advantages of simplifying the production process, reducing the production cost, improving the sealing quality of the negative electrode end, increasing the accommodating space of the battery core and the like are achieved; meanwhile, the welding structure of the positive electrode end is also improved, so that the firmness of a welding spot is improved, and the reliability of welding quality is ensured; besides, the battery cell is formed by laminating and tightly winding the positive pole piece, the diaphragm paper and the negative pole piece, and seepage channels are reserved between the positive pole piece and the diaphragm paper as well as between the diaphragm paper and the negative pole piece for rapid seepage of electrolyte, so that the difficulty of seepage of the electrolyte into the battery cell is reduced, the seepage efficiency is improved, and enough seepage amount is increased.

Description

Technical Field

[0001] The utility model relates to a lithium battery structure, in particular to an improved lithium battery structure. Background Art

[0002] At present, the structure of a lithium battery is mainly composed of an outer shell, a battery cell in the outer shell, and a positive terminal and a negative terminal at both ends of the closed outer shell. The positive terminal includes a positive current collector, an insulating sealing ring, an insulating ring, a positive current collector column, a positive sealing ring, a positive pressure ring, a positive insulating cover and a positive cap, and the negative terminal includes a negative current collector, a plastic sealing ring and a negative bottom cover. In the manufacturing process of the negative terminal, it is necessary to first process a groove on the outer surface of the outer shell, and the concave part of the groove presses the negative current collector and the battery cell in the outer shell, and then the plastic sealing ring is placed and the negative bottom cover is used to seal it. Therefore, during the manufacturing process, due to the presence of the plastic sealing ring, the negative bottom cover is often prone to sealing quality problems when it is closed. Moreover, the grooving process also makes the production process of lithium batteries more complicated and increases the production cost. In particular, the concave part formed by the grooving process combined with the design of the plastic sealing ring will also increase the sealing structure space in the outer shell, which correspondingly compresses the accommodation space of the battery cell, thereby affecting the battery capacity. At the same time, the positive sealing ring of the positive end is installed in the injection hole of the positive current collecting column, so that a circle of weld is formed between the top of the positive sealing ring and the top of the positive current collecting column, and the weld needs to be welded by laser circumferential welding to realize the welding and fixation of the positive sealing ring in the injection hole, and the positive pressure ring is sleeved outside the positive current collecting column, so that a circle of weld is also formed between the top of the positive pressure ring and the top of the positive current collecting column, and the weld also needs to be welded by laser circumferential welding to realize the welding and fixation of the positive pressure ring outside the positive current collecting column; however, in the actual manufacturing process, since the circle of weld between the top of the positive sealing ring and the top of the positive current collecting column, and the circle of weld between the top of the positive pressure ring and the top of the positive current collecting column are straight through from top to bottom, it is often easy to cause welding penetration welds when performing laser circumferential welding, which will cause poor firmness of the weld point and affect the reliability of welding quality. In addition, in order to ensure the service life of lithium batteries, sufficient electrolyte is usually required to penetrate into the battery cells. However, existing battery cells are made of positive electrode plates, diaphragm paper and negative electrode plates stacked and tightly wound, so the gaps between them are quite dense. This causes defects such as difficulty in electrolyte penetration into the battery cells, low electrolyte penetration efficiency and insufficient electrolyte penetration during the lithium battery production process. Utility Model Content

[0003] The technical problem to be solved by the utility model is to overcome the defects of the prior art and provide an improved lithium battery structure which simplifies the production process, reduces the production cost, improves the sealing quality of the negative terminal and increases the battery cell accommodating space, enhances the welding quality of the positive terminal, reduces the difficulty of electrolyte infiltration into the battery cell, improves the infiltration efficiency and increases the sufficient infiltration amount.

[0004] The technical problem of the utility model is achieved through the following technical solutions:

[0005] An improved lithium battery structure comprises an outer shell, an electric cell in the outer shell, and a positive terminal and a negative terminal enclosing both ends of the outer shell; the positive terminal comprises a positive current collector, an insulating sealing ring, an insulating ring, a positive current collector column, a positive sealing ring, a positive pressure ring, a positive insulating cover and a positive cap, the positive sealing ring is fitted in the injection hole of the positive current collector column and is welded and fixed, and the positive pressure ring is sleeved on the outside of the positive current collector column and is also welded and fixed; the negative terminal comprises a negative current collector welded on the electric cell to form a conductive connection and a negative bottom cover enclosing the negative current collector, the outer circumference of the negative bottom cover is provided with a folded edge bent outwardly, and the outer circumference of the negative current collector is provided with a surrounding edge bent outwardly; the surrounding edge is circumferentially welded in the outer shell; the folded edge is circumferentially welded in the outer shell through the outer folded section, and a caulking is formed between the inner folded section of the folded edge and the inner circumferential surface of the outer shell and is inserted into the surrounding edge.

[0006] The inner circumference of the injection hole is provided with an inner shoulder, and the positive electrode sealing ring is matched with the inner shoulder; the outer circumference of the positive electrode current collecting column is provided with an outer shoulder, and the positive electrode pressure ring is matched with the outer shoulder.

[0007] The negative electrode current collector is composed of a body and a surrounding edge fixed on the outer circumference of the body. The body is made of a material suitable for welding and fixing the pole ears of the battery cell, and the surrounding edge is made of a material suitable for circumferential welding and fixing the shell.

[0008] The surrounding edge is composed of a horizontal ring and a vertical ring formed by right-angle bending.

[0009] The outer circumference of the main body is provided with a bending portion with a circumference bent, and the main body is welded and fixed on the horizontal ring of the surrounding edge through the bending portion.

[0010] The horizontal ring is provided with a plurality of rivet holes, and the outer circumferential surface of the main body is provided with a plurality of rivet joints corresponding to the rivet holes. The main body is punched and riveted into the plurality of rivet holes on the horizontal ring through the plurality of rivet joints.

[0011] The folded edge is bent in the middle to form an inner folded section and an outer folded section respectively.

[0012] The battery core is formed by stacking and tightly winding a positive electrode sheet, a separator paper and a negative electrode sheet, and a liquid seepage channel is left between the positive electrode sheet and the separator paper, and between the separator paper and the negative electrode sheet.

[0013] The outer surface of the diaphragm paper is provided with a plurality of seepage grooves, which are arranged equidistantly along the winding direction of the diaphragm paper, each seepage groove is parallel to the winding axis, both ends of each seepage groove penetrate the diaphragm paper respectively, and seepage channels are formed between the positive electrode sheet and the diaphragm paper, and between the diaphragm paper and the negative electrode sheet through the seepage grooves.

[0014] The seepage groove is a semicircular groove, a triangular groove or a trapezoidal groove.

[0015] Compared with the prior art, the utility model mainly has a folded edge bent outwardly on the outer circumference of the negative electrode bottom cover, and a surrounding edge bent outwardly on the outer circumference of the negative electrode current collector; and the surrounding edge is circumferentially welded in the outer shell, and the folded edge is also circumferentially welded in the outer shell through the outer folded section, and the inner folded section of the folded edge forms a seam with the inner circumferential surface of the outer shell and is inserted into the surrounding edge. In this way, since the improved negative terminal of the lithium battery has eliminated the plastic sealing ring and the grooving process that are required in the traditional structure, the overall structure is simpler, thereby simplifying the production process, reducing production costs, improving the sealing quality of the negative terminal, and increasing the cell accommodating space to increase the battery capacity. At the same time, the welding structure of the positive terminal has also been improved. Specifically, an inner shoulder is provided on the inner circumferential surface of the injection hole of the positive current collecting column, and the positive sealing ring is matched with the inner shoulder, while an outer shoulder is provided on the outer circumferential surface of the positive current collecting column, and the positive pressure ring is matched with the outer shoulder, so that the top of the positive sealing ring can be ensured to be matched with the positive current collecting column. A circle of welds between the tops, and a circle of welds between the top of the positive pressure ring and the top of the positive current collecting column are blocked by the inner shoulder and the outer shoulder respectively and cannot form a straight through up and down connection. Therefore, when laser circular welding is performed, the weld will not penetrate the weld, thereby improving the firmness of the weld point and ensuring the reliability of the welding quality. In addition, when the battery cell is composed of the positive electrode sheet, diaphragm paper and negative electrode sheet stacked and tightly wound, seepage channels are reserved between the positive electrode sheet and the diaphragm paper, and between the diaphragm paper and the negative electrode sheet. Therefore, the electrolyte can quickly penetrate into the battery cell through these seepage channels, thereby effectively reducing the difficulty of electrolyte infiltration into the battery cell, improving the seepage efficiency and increasing a sufficient amount of seepage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional structural schematic diagram of the utility model.

[0017] Figure 2 A cross-sectional view of the negative terminal.

[0018] Figure 3 for Figure 2 Enlarged view of point A.

[0019] Figure 4 for Figure 3 Schematic diagram of the structure with the negative electrode current collector removed.

[0020] Figure 5 for Figure 3 A cross-sectional view of the first structure of the middle negative electrode current collector.

[0021] Figure 6 for Figure 3 A cross-sectional view of the second structure of the middle negative electrode current collector.

[0022] Figure 7 For application Figure 6 Schematic diagram of the negative electrode current collector of the structure.

[0023] Figure 8 for Figure 2 Top view of the .

[0024] Fig. 9 for Figure 2 Stereoscopic diagram.

[0025] Fig.10 It is a cross-sectional view of the negative electrode bottom cover.

[0026] Fig.11 A cross-sectional view of the positive terminal.

[0027] Fig.12 This is an enlarged cross-sectional view of the positive electrode current collecting column.

[0028] Fig.13 A schematic diagram of the structure of a battery cell.

[0029] Fig.14 for Fig.13 Enlarged view of point B.

[0030] Fig.15 Schematic diagram of the unfolded separator paper structure.

[0031] Fig.16 for Fig.15 Top view of the .

[0032] Fig.17 for Fig.15 Stereoscopic diagram. DETAILED DESCRIPTION

[0033] The embodiments of the present invention will be described in detail below according to the above-mentioned drawings.

[0034] like Figure 1 to Figure 17As shown, 1. shell, 2. battery cell, 3. positive terminal, 31. positive current collector, 32. insulating ring, 33. positive current collector column, 331. inner shoulder, 332. outer shoulder, 333. injection hole, 34. positive sealing ring, 35. positive electrode cap, 36. positive electrode pressure ring, 37. positive electrode insulating cover, 38. insulating sealing ring, 4. negative terminal, 41. negative current collector, 411. body, 412. surrounding edge, 413. bending part, 414. horizontal ring, 415. vertical ring, 416. rivet hole, 417. rivet joint, 42. negative bottom cover, 43. folded edge, 431. outer folded section, 432. inner folded section, 5. caulking, 6. diaphragm paper, 61. seepage channel, 611. seepage groove.

[0035] An improved lithium battery structure, such as Figure 1 As shown, it is mainly composed of a shell 1, a battery cell 2 in the shell, and a positive terminal 3 and a negative terminal 4 at both ends of the closed shell. The shell 1 is a cylindrical steel shell, and other materials or shapes can also be used.

[0036] The positive terminal 3 is as follows Fig.11 , Fig.12 As shown, it includes a positive current collecting sheet 31 welded on the battery cell 2 to form a conductive connection, an insulating sealing ring 38 arranged on the positive current collecting sheet 31, an insulating ring 32 arranged between the positive current collecting sheet 31 and the outer shell 1, a positive current collecting column 33 welded and fixed on the positive current collecting sheet 31, a positive sealing ring 34 fitted in the injection hole 333 of the positive current collecting column 33 and welded and fixed, a positive pressure ring 36 sleeved on the outside of the positive current collecting column 33 and also welded and fixed, a positive cap 35 that simultaneously seals the positive current collecting column 33, the positive sealing ring 34 and the positive pressure ring 36, and a positive insulating cover 37 arranged on the periphery of the positive cap 35.

[0037] In addition, an inner shoulder 331 is provided on the inner circumference of the injection hole 333, and the positive electrode sealing ring 34 is matched with the inner shoulder, and an outer shoulder 332 is provided on the outer circumference of the positive electrode current collecting column 33, and the positive electrode pressure ring 36 is matched with the outer shoulder.

[0038] In this way, it can be ensured that a circle of welds between the top of the positive sealing ring 34 and the top of the positive current collecting column 33, as well as a circle of welds between the top of the positive pressure ring 36 and the top of the positive current collecting column 33, are respectively blocked by the inner shoulder 331 and the outer shoulder 332 and cannot form a straight through from top to bottom. Therefore, when performing laser circular welding, the weld will not penetrate the weld, thereby improving the firmness of the weld point and ensuring the reliability of the welding quality.

[0039] The negative terminal 4 comprises a negative electrode current collector 41 welded on the battery cell 2 and forming a conductive connection and a negative electrode bottom cover 42 sealing the negative electrode current collector. Figure 1 The circumference of the negative electrode current collector 41 is bent downward, and the circumference can be directly connected to the outer circumference of the negative electrode current collector 41 and bent toward the outer circumference, or the negative electrode current collector 41 can be divided into two separate parts: a main body 411 and a circumference 412. The main body 411 is a circular sheet, mainly made of copper material suitable for welding and fixing the pole ears of the battery cell 2, and the circumference 412 is mainly made of iron material suitable for circumferential welding and fixing the outer shell 1, that is, the circumference 412 is fixed to the outer circumference of the main body 411 to form a whole.

[0040] Of course, in the actual manufacturing process, the materials of the main body 411 and the surrounding edge 412 can be freely selected, as long as the main body 411 is suitable for welding and fixing the tabs of the battery cell 2 and the surrounding edge 412 is suitable for circumferential welding and fixing the shell 1.

[0041] Meanwhile, when the negative electrode current collector 41 is divided into two separate parts, namely, the main body 411 and the surrounding edge 412, the surrounding edge 412 may be composed of a horizontal ring 414 and a vertical ring 415 formed by right-angle bending, the forming process of the negative electrode current collector 41 is mainly divided into two types: the first type is as follows: Figure 5 As shown, the outer circumference of the body 411 may be provided with a circumferentially bent bending portion 413, and the body is welded and fixed to the horizontal ring 414 of the surrounding edge 412 through the bending portion 413; the second type is as follows Figure 6 , Figure 7 As shown, the horizontal ring 414 is provided with a plurality of circumferentially distributed rivet holes 416, and correspondingly, the outer circumferential surface of the main body 411 is also provided with a plurality of rivet joints 417 that are evenly distributed around the circumference and correspond to the rivet holes 416. The main body 411 can be punched and riveted into the plurality of rivet holes 416 on the horizontal ring 414 through the plurality of rivet joints 417.

[0042] In this way, the welding process of the negative electrode current collector 41 is: first weld and fix the surrounding edge 412 to the outer circumference of the main body 411, then weld and fix the main body 411 and the pole ear of the battery cell 2, and finally weld and fix the surrounding edge 412 and the outer shell 1 in a circular manner, that is, the negative electrode current collector 41 is welded in the outer shell 1 through the surrounding edge 412 in a circular manner.

[0043] The main body 411 is made of copper and the surrounding edge 412 is made of iron. This is because the tabs of the battery cell 2 are made of copper and the outer shell 1 is made of steel. If the negative electrode collector 41 is made entirely of copper, although it can ensure that it is firmly welded to the tabs of the battery cell 2, the difference in material between the tabs and the outer shell 1 may lead to poor welding firmness. If the negative electrode collector 41 is made entirely of iron, although it can ensure that it is firmly welded to the outer shell 1, due to the difference in material between the tabs and the battery cell 2, a chemical reaction may easily occur after welding, resulting in poor welding firmness. This will affect the conductivity between the battery cell 2 and the negative electrode collector 41, thereby causing a decrease in the quality of the battery cell 2.

[0044] The outer circumference of the negative electrode bottom cover 42 is also provided with a circumference that is bent outwards, i.e. Figure 1 The folded edge 43 shown is circumferentially bent downward, that is, the folded edge 43 and the surrounding edge 412 are bent in the same direction, and the folded edge is also bent in the middle to form an inner folded section 432 and an outer folded section 431 respectively. Therefore, the folded edge 43 is also circumferentially welded in the outer shell 1 through the outer folded section 431, and a caulking 5 is formed between the inner folded section 432 of the folded edge and the inner circumferential surface of the outer shell 1 and is inserted into the surrounding edge 412, that is, a space for accommodating the surrounding edge 412 is formed by the caulking 5.

[0045] Obviously, since the improved negative terminal of the lithium battery has eliminated the plastic sealing ring and grooving process that are required in the traditional structure, the overall structure will be simpler, thereby simplifying the production process, reducing production costs, and increasing the cell accommodation space to increase battery capacity. In particular, the elimination of the plastic sealing ring can also improve the sealing quality of the negative terminal.

[0046] The battery cell 2 is formed by stacking and tightly winding a positive electrode sheet, a separator paper 6 and a negative electrode sheet, and leaving a seepage channel 61 between the positive electrode sheet and the separator paper 6, and between the separator paper and the negative electrode sheet. The specific structure is as follows: Figure 13~Figure 17 As shown: the outer surface of the diaphragm paper 6 is provided with a plurality of seepage grooves 611, and the plurality of seepage grooves are arranged equidistantly along the winding direction of the diaphragm paper 6, and each seepage groove 611 is parallel to the winding axis, and both ends of each seepage groove 611 respectively penetrate the diaphragm paper 6, and in particular, the plurality of seepage grooves 611 are directly pressed on the diaphragm paper 6, so that the two sides of the diaphragm paper 6 can form concave-convex groove-shaped gaps through the plurality of pressed seepage grooves 61, so that seepage channels 61 can be formed between the positive electrode sheet and the diaphragm paper 6, and between the diaphragm paper and the negative electrode sheet through these seepage grooves 611.

[0047] In this way, the electrolyte can quickly penetrate into the battery cell 2 through these penetration channels 61, thereby reducing the difficulty of electrolyte penetration into the battery cell, improving the penetration efficiency and increasing a sufficient amount of penetration to ensure the service life of the lithium battery.

[0048] In addition, in actual design, the seepage groove 611 is usually a semicircular groove, a triangular groove, or a trapezoidal groove. Of course, grooves of any other shapes can also be selected.

[0049] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design equivalent to this embodiment should be included in the protection scope of the present invention.

Claims

1. An improved lithium battery structure, comprising a shell (1), a battery cell (2) in the shell, and a positive terminal (3) and a negative terminal (4) sealing both ends of the shell; the positive terminal comprises a positive current collector (31), an insulating seal ring (38), an insulating ring (32), a positive current collector column (33), a positive seal ring (34), a positive pressure ring (36), a positive insulating cover (37) and a positive cap (35); the positive seal ring (34) is fitted into a liquid injection hole (333) of the positive current collector column (33) and is welded and fixed; the positive pressure ring (36) is sleeved on the outside of the positive current collector column (33) and is also welded and fixed; the negative terminal (4) comprises a negative current collector (41) welded to the battery cell (2) and forming a conductive connection and a negative bottom cover (42) sealing the negative current collector, characterized in that The outer circumference of the negative electrode bottom cover (42) is provided with a folded edge (43) that is folded outwardly, and the outer circumference of the negative electrode current collector (41) is provided with a surrounding edge (412) that is folded outwardly; the surrounding edge is circumferentially welded inside the outer shell (1); the folded edge (43) is circumferentially welded inside the outer shell (1) via the outer folded section (431), and a caulking (5) is formed between the inner folded section (432) of the folded edge (43) and the inner circumferential surface of the outer shell (1) and is inserted into the surrounding edge (412).

2. An improved lithium battery structure according to claim 1, characterized in that An inner shoulder (331) is provided on the inner circumferential surface of the injection hole (333), and the positive electrode sealing ring (34) is fitted with the inner shoulder; an outer shoulder (332) is provided on the outer circumferential surface of the positive electrode current collecting column (33), and the positive electrode pressing ring (36) is fitted with the outer shoulder.

3. An improved lithium battery structure according to claim 1, characterized in that The negative electrode current collector (41) is composed of a main body (411) and a peripheral edge (412) fixed to the outer circumference of the main body, and the main body (411) is made of a material suitable for welding and fixing the pole lugs of the battery cell (2), and the peripheral edge (412) is made of a material suitable for circumferential welding and fixing the outer shell (1).

4. An improved lithium battery structure according to claim 3, characterized in that The surrounding edge (412) is composed of a horizontal ring (414) and a vertical ring (415) formed by right-angle bending.

5. An improved lithium battery structure according to claim 4, characterized in that The outer circumference of the main body (411) is provided with a circumferentially bent bending portion (413), and the main body (411) is welded and fixed to the horizontal ring (414) of the surrounding edge (412) via the bending portion (413).

6. An improved lithium battery structure according to claim 4, characterized in that The horizontal ring (414) is provided with a plurality of rivet holes (416), and a plurality of rivet joints (417) corresponding to the rivet holes (416) are provided on the outer circumferential surface of the body (411). The body (411) is punched and riveted into the plurality of rivet holes (416) on the horizontal ring (414) via the plurality of rivet joints (417).

7. The improved lithium battery structure according to claim 1, characterized in that The folded edge (43) is bent in the middle to form an inner folded section (432) and an outer folded section (431).

8. The improved lithium battery structure according to claim 1, characterized in that The battery core (2) is formed by stacking and tightly winding a positive electrode sheet, a separator paper (6) and a negative electrode sheet, and a liquid seepage channel (61) is left between the positive electrode sheet and the separator paper (6), and between the separator paper (6) and the negative electrode sheet.

9. An improved lithium battery structure according to claim 8, characterized in that The outer surface of the separator paper (6) is provided with a plurality of seepage grooves (611), the plurality of seepage grooves (611) are arranged equidistantly along the winding direction of the separator paper (6), each seepage groove (611) is parallel to the winding axis, both ends of each seepage groove (611) respectively penetrate the separator paper (6), and seepage channels (61) are formed between the positive electrode sheet and the separator paper (6), and between the separator paper (6) and the negative electrode sheet through the seepage grooves (611).

10. An improved lithium battery structure according to claim 9, characterized in that The seepage groove (611) is a semicircular groove, a triangular groove, or a trapezoidal groove.

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