A simple lithium battery end sealing structure and manufacturing method

Abstract

The present invention discloses a simple lithium battery end sealing structure and manufacturing method, including a shell, a battery cell and a current collector, etc., mainly adding a current collector cover outside the current collector, and making the inner end face of the current collector seal tightly against the outer end face of the current collector, and then providing inner and outer support rings on the outer end face of the current collector, and the inner support ring is fixed to the boss, and the outer support ring is fixed to the shell, so as to press the current collector cover to achieve the end sealing of the lithium battery. Obviously, the sealing of the end of the above-mentioned lithium battery is mainly undertaken by two structures respectively, so there is no need to use circumferential welding, and it is sufficient to ensure that the inner support ring and the boss, and the outer support ring and the battery shell can be fixed, which greatly reduces the requirements of the welding process; at the same time, this structural design is simpler, and combined with the corresponding manufacturing method, it can save welding time, improve manufacturing efficiency, avoid welding leaks and reduce welding shielding gas pollution, etc.; at the same time, the manufacturing method without circumferential welding also greatly reduces the manufacturing cost of lithium batteries.

Description

Technical Field

[0001] The invention relates to a lithium battery end sealing structure, in particular to a simple lithium battery end sealing structure and a manufacturing method thereof. Background Art

[0002] At present, the end sealing is required in the production and manufacturing process of lithium batteries. Specifically, the collector sheet is first installed at the end of the shell to seal the battery cell in the shell, and then the collector sheet and the battery cell are electrically conductive; at the same time, a collector ring is also required on the collector sheet, and the collector ring and the shell need to be sealed and fixed by circumferential welding to seal the collector sheet inside, and finally, an insulating cover is placed on the collector ring, and the end sealing is completed by pressing and fixing it through the curling of the outer edge of the shell. Obviously, the above-mentioned lithium battery end sealing structure is not only complex in design, but also the collector ring that seals the collector sheet must be sealed by circumferential welding, that is, the collector ring welded by circumferential welding is used to simultaneously bear the connection and sealing, which has high requirements for welding technology, and there are also defects such as long welding time, low manufacturing efficiency, easy welding leakage and welding shielding gas pollution environment; at the same time, this circumferential welding method requires the configuration of a special laser welding machine, which also increases the manufacturing cost of lithium batteries. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a simple lithium battery end sealing structure and a manufacturing method which can complete the lithium battery end sealing only through simple structural design without circumferential welding sealing.

[0004] The technical problem of the present invention is achieved through the following technical solutions:

[0005] A simple lithium battery end sealing structure comprises an outer shell, a battery cell in the outer shell and a current collector installed at the end of the outer shell. The current collector seals the battery cell in the outer shell and forms electrical conduction with the battery cell. A boss protruding outward is provided in the middle of the current collector. A current collecting cover is provided outside the current collector. The inner end face of the current collecting cover is sealed tightly against the outer end face of the current collector. An inner supporting ring and an outer supporting ring are provided on the outer end face of the current collecting cover. The inner supporting ring is fixed to the boss, and the outer supporting ring is fixed to the outer shell.

[0006] The outer edge of the current collecting cover is provided with a bent edge that is circumferentially bent outward, and the bent edge circumferentially covers the outer edge of the outer support ring. The outer edge of the outer shell end is provided with a circumferentially folded outer rolled mouth, which covers and seals the bent edge inside and is fixed to the outer support ring; or the outer edge of the current collecting cover is directly circumferentially pressed against the outer shell to form a seal, and the outer edge of the outer support ring is directly circumferentially contacted with the outer shell and fixed.

[0007] The inner edge of the outer support ring is provided with an inner extension edge which extends inwards and is embedded in the current collecting cover.

[0008] A through hole is provided in the middle of the current collecting cover for exposing the boss, and a circumferential inclined surface sealing contact or a circumferential vertical surface sealing contact is made between the hole wall of the through hole and the outer surface of the boss.

[0009] The outer circumferential surface of the boss is provided with an inner rolled opening with a circumferential fold, which is fixed to the inner support ring, or the inner edge of the inner support ring is directly in circumferential contact with the boss and fixed; the outer edge of the inner support ring is provided with an outer extension edge extending outward and embedded in the collecting cover.

[0010] The current collector is composed of a current collecting sheet and a current collecting ring. The current collecting ring forms a boss protruding outward, and the outer edge of the current collecting ring is conductively connected to the inner edge of the current collecting sheet.

[0011] The boss is provided with a central hole penetrating along the axis, and the central hole is provided with a cap or boss sealing the central hole, which is a fully enclosed boss, and a magnetic sheet is provided on the fully enclosed boss.

[0012] The outer edge of the current collector is provided with a folded edge that is circumferentially bent inward, and an insulating ring is provided between the folded edge and the outer shell.

[0013] The outer circumferential surface of the shell is provided with a rolling groove, and the insulating ring is positioned and fixed in the shell by the rolling groove, or the outer support ring squeezes the insulating ring through the collecting cover and positions and fixes the insulating ring in the shell.

[0014] A method for manufacturing a simple lithium battery end sealing structure comprises the following steps:

[0015] Step 1: Take the outer shell of the lithium battery and install the battery cell inside;

[0016] Step 2: Install the current collector at the end of the shell through the insulating ring so that the battery cell is enclosed in the shell and conduction is formed between the current collector and the battery cell;

[0017] Step 3: A boss protruding outward is provided in the middle of the current collector; if the end of the lithium battery is a positive terminal, a middle hole penetrating along the axis and a cap sealing the middle hole are provided in the boss; if the end of the lithium battery is a negative terminal, the boss is a fully enclosed boss, and a magnetic sheet is provided on the fully enclosed boss;

[0018] Step 4: a current collecting cover is arranged outside the current collector, the inner end face of the current collecting cover is tightly sealed against the outer end face of the current collector, and a through hole is arranged in the middle of the current collecting cover for exposing the boss, and a circumferential inclined sealing contact or a circumferential vertical sealing contact is made between the hole wall of the through hole and the outer surface of the boss;

[0019] Step 5: Arrange an inner support ring and an outer support ring on the outer end surface of the current collecting cover;

[0020] Step 6: Fix the inner support ring to the boss. There are two types of fixing structures: one is that the outer circumferential surface of the boss is provided with an inner rolled opening with a circumferential fold, and the inner rolled opening is fixed to the inner support ring; the other is that the inner edge of the inner support ring is directly in circumferential contact with the boss and fixed;

[0021] Step 7, fix the outer support ring to the outer shell. The fixing structure is also divided into two types; one is that a curved edge with a circumference bent outward is provided on the outer edge of the current collecting cover, and the curved edge covers the outer edge of the outer support ring, and at the same time, a circumferentially folded outer rolled mouth is provided on the outer edge of the outer shell end, and the outer rolled mouth covers the curved edge and seals it inside, and is fixed to the outer support ring; the other is that the outer edge of the current collecting cover is directly circumferentially close to the outer shell and forms a seal, and the outer edge of the outer support ring is directly circumferentially in contact with the outer shell and fixed;

[0022] Step 8: After the inner and outer support rings are fixed to the boss and the outer shell respectively, the inner end surface of the current collector cap and the outer end surface of the current collector can be sealed tightly, thereby completing the sealing manufacturing of the lithium battery port.

[0023] Compared with the prior art, the present invention mainly adds a current collecting cover outside the current collector, and makes the inner end face of the current collecting cover seal tightly against the outer end face of the current collector, and then provides an inner support ring and an outer support ring on the outer end face of the current collecting cover, and the inner support ring is fixed to the boss, and the outer support ring is fixed to the outer shell of the lithium battery, thereby pressing the current collecting cover to achieve the end sealing of the lithium battery. Obviously, the sealing and closure of the lithium battery end of the above structure is mainly achieved through the tightly fitting collecting cover, and the connection between the collecting cover and the outer shell is achieved through the inner and outer support rings, that is, the sealing and closure of the lithium battery end are undertaken by two structures respectively. Compared with the traditional lithium battery end which mainly relies on the collecting ring for circumferential welding to connect and seal at the same time, the simplified lithium battery end sealing structure omits the circumferential welding method, and only needs to ensure that the inner support ring and the boss, the outer support ring and the outer shell can be fixed, so the requirements for the welding process are greatly reduced; at the same time, this structural design is simpler, and combined with the corresponding manufacturing method, it can save welding time, improve manufacturing efficiency, avoid welding leaks and reduce welding shielding gas pollution; in addition, the manufacturing method without circumferential welding also greatly reduces the manufacturing cost of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a first structural cross-sectional view of the present invention.

[0025] Figure 2 for Figure 1 Magnified cross-sectional view of the positive end.

[0026] Figure 3 for Figure 1 Magnified cross-sectional view of the negative end.

[0027] Figure 4 This is a cross-sectional view of the second structure of the present invention.

[0028] Figure 5 for Figure 4 Magnified cross-sectional view of the positive end.

[0029] Figure 6 for Figure 4 Magnified cross-sectional view of the negative end.

[0030] Figure 7 for Figure 2 Schematic diagram of the cross-sectional structure of the middle collecting cover.

[0031] Figure 8 for Figure 5 Schematic diagram of the cross-sectional structure of the middle collecting cover.

[0032] Fig. 9 It is a schematic diagram of the cross-sectional structure of the current collector.

[0033] Fig.10 for Figure 2 Schematic diagram of the cross-sectional structure of the middle collector ring (boss).

[0034] Fig.11 for Figure 3 Schematic diagram of the cross-sectional structure of the middle collector ring (boss). DETAILED DESCRIPTION

[0035] The embodiments of the present invention will be described in detail below with reference to the above-mentioned drawings.

[0036] like Figure 1 to Figure 11 As shown, 1. shell, 11. battery cell, 12. outer rolled mouth, 13. rolling groove, 2. current collector, 21. current collecting sheet, 211. folded edge, 22. current collecting ring, 221. middle hole, 222. inner rolled mouth, 223. groove, 3. current collecting cover, 31. through hole, 32. bent edge, 33. embedded groove, 34. circumferential inclined surface, 35. circumferential vertical surface, 4. inner support ring, 41. outer extension edge, 5. outer support ring, 51. inner extension edge, 6. insulating ring, 7. cap, 8. sealing ring, 9. boss, 10. magnetic sheet.

[0037] A simple lithium battery end sealing structure and manufacturing method, such as Figure 1As shown, it can be applied to the end sealing of the positive terminal and the negative terminal of the lithium battery at the same time. Its structure is mainly composed of a shell 1, a battery cell 11 in the shell, and a current collector 2 installed at the end of the shell 1. The current collector is provided with a current collector cover 3 outside, and the current collector cover is made of a non-conductive rubber sealing material, and its inner end face is sealed tightly against the outer end face of the current collector. The outer end face of the current collector cover 3 is provided with an inner support ring 4 and an outer support ring 5, and the inner support ring is fixed to the boss 9, and the outer support ring is fixed to the shell 1. Since this embodiment is described by taking a cylindrical lithium battery as an example, the shapes of the shell 1, the current collector 2, the current collector cover 3, the inner support ring 4 and the outer support ring 5 are also mainly circular or annular.

[0038] The current collector 2 is composed of a current collecting sheet 21 and a current collecting ring 22. The current collecting ring forms an outwardly protruding boss 9. In fact, the boss is located at the center of the current collector 2 and protrudes outward, and the outer edge of the current collecting ring 22 is conductively connected to the inner edge of the current collecting sheet 21.

[0039] The current collector 2 is composed of two structures in order to meet the use requirements in the actual manufacturing process by using two kinds of materials for the current collecting sheet 21 and the current collecting ring 22 respectively.

[0040] At the same time, the structures of the bosses 9 at the positive and negative ends are also different. Fig.10 As shown, the boss 9 is provided with a central hole 221 penetrating along the axis, and the central hole is provided with a cap 7 which is sealed by a sealing ring 8 to cover the central hole. The cap needs to have a safety pressure relief device, such as a safety valve, etc.; the boss at the negative end is as shown Fig.11 As shown, the boss 9 is actually a fully enclosed boss, and the fully enclosed boss is also provided with a magnetic sheet 10 embedded in the groove 223, and the function of the magnetic sheet 10 is: during the lithium battery manufacturing process, a REID digital identification code can be absorbed by the magnetic sheet 10, so as to detect, record, store and track the process assembly and process parameters of the entire lithium battery.

[0041] The fixing structure of the inner support ring 4 and the boss 9 is divided into two types: one is as follows: Figure 2 , Figure 3 As shown, on the outer circumferential surface of the boss 9, specifically the outer circumferential surface of the collector ring 22, there is a circumferentially folded inner roll 222, which presses the top surface of the inner support ring 4 and is welded and fixed to the inner support ring through a plurality of welding points; another example is Figure 5 , Figure 6 As shown, the inner edge of the inner support ring 4 is directly in circumferential contact with the boss 9, and then is welded and fixed through a plurality of welding points.

[0042] The outer edge of the inner support ring 4 is provided with an outer edge 41 which surrounds the circumference and extends outward, and the outer edge is directly embedded in the current collector 3. The design of the outer edge 41 is combined with the fixing structure between the inner edge of the inner support ring 4 and the boss 9, so as to enhance the installation and fixation of the inner support ring 4 on the outer end face of the current collector 3.

[0043] The fixing structure of the outer support ring 5 and the housing 1 is also divided into two types: one is as follows: Figure 2 , Figure 3 As shown, the outer edge of the current collecting cover 3 is provided with a circumferentially outwardly bent edge 32, which wraps the outer edge of the outer support ring 5, and the outer edge of the end of the shell 1 is provided with a circumferentially folded outer roll 12, which wraps the bent edge 32 and seals it inside, and is welded and fixed to the outer support ring 5 through a plurality of welding points; another example is Figure 5 , Figure 6 As shown, the outer edge of the collecting cover 3 is directly circumferentially in close contact with the outer shell 1 to form a seal, and the outer edge of the outer support ring 5 is directly circumferentially in contact with the outer shell 1, and then is welded and fixed through a plurality of welding points.

[0044] The inner edge of the outer support ring 5 is provided with an inner extension 51 which surrounds the circumference and extends inward, and the inner extension is directly embedded in the current collector 3. The design of the inner extension 51 is combined with the fixing structure between the outer edge of the outer support ring 5 and the outer shell 1 to enhance the installation and fixation of the outer support ring 5 on the outer end face of the current collector 3.

[0045] After the inner and outer support rings are welded and fixed, they are respectively fitted into the preset grooves 33 on the outer end faces of the collecting cover 3, so that a double ring with the same center is formed between the two, and a support frame structure is formed to press the collecting cover 3 inside. At this time, the outer end faces of the inner and outer support rings are also flush with the outer end faces of the collecting cover 3 exposed between the two.

[0046] The collecting cover 3 is provided with a through hole 31 in the middle for exposing the boss 9. The hole wall of the through hole and the outer surface of the boss 9 can be sealed by a circumferential inclined surface 34 or a circumferential vertical surface 35 to meet the selection under various sealing conditions.

[0047] In addition, the installation structure between the current collector 2 and the end of the shell 1 is: the outer edge of the current collector 2 is provided with a folded edge 211 that is folded inward in a circumferential direction, and an insulating ring 6 is provided between the folded edge and the shell 1. While the installation is achieved through the insulating ring, the installation position is also positioned in the shell 1.

[0048] The insulating ring 6 of this embodiment mainly adopts two positioning structures, one is as follows: Figure 2 , Figure 3 As shown, a circumferential rolling groove 13 is provided on the outer circumferential surface of the housing 1, and the insulating ring 6 is positioned and fixed in the housing 1 by the concave of the rolling groove. Figure 5, Figure 6 As shown, the insulating ring 6 is squeezed through the outer support ring 5 through the collecting cover 3 and the insulating ring is positioned and fixed in the housing 1.

[0049] In this way, the battery cell 11 can be enclosed in the housing 1 by means of the current collector 2 installed at the end of the housing 1, and the current collector is then welded to form electrical conduction with the battery cell 11.

[0050] The manufacturing method of this simplified lithium battery end sealing structure mainly includes the following steps:

[0051] Step 1: Take the outer shell 1 of the lithium battery and install the battery cell 11 inside;

[0052] Step 2: Install the current collector 2 at the end of the housing 1 through the insulating ring 6, and also seal the battery cell 11 in the housing 1, so that the current collector 2 and the battery cell 11 are electrically conductive;

[0053] Step 3: A boss 9 protruding outward is provided in the middle of the current collector 2. If the end of the lithium battery is a positive terminal, a middle hole 221 penetrating along the axis and a cap 7 sealing the middle hole are provided in the boss; if the end of the lithium battery is a negative terminal, the boss 9 is a fully enclosed boss, and a magnetic sheet 10 is provided on the fully enclosed boss;

[0054] Step 4: a current collecting cover 3 is arranged outside the current collector 2, and the inner end surface of the current collecting cover is sealed tightly against the outer end surface of the current collector. Meanwhile, a through hole 31 is arranged in the middle of the current collecting cover 3 for exposing the boss 9. The hole wall of the through hole is in sealing contact with the outer surface of the boss 9 by a circumferential inclined surface 34 or a circumferential vertical surface 35;

[0055] Step 5: The outer end surface of the current collecting cover 3 is provided with an inner support ring 4 and an outer support ring 5;

[0056] Step 6: Fix the inner support ring 4 to the boss 9. There are two types of fixing structures: one is that the outer circumferential surface of the boss 9 is provided with an inner rolled opening 222 with a circumferential fold, and the inner rolled opening is fixed to the inner support ring 5; the other is that the inner edge of the inner support ring 4 is directly in circumferential contact with the boss 9 and fixed;

[0057] Step 7, fix the outer support ring 5 to the outer shell 1, and the fixing structure is also divided into two types; one is that a curved edge 32 with a circumference bent outward is provided on the outer edge of the current collecting cover 3, and the outer edge of the outer support ring 5 is covered by the curved edge, and at the same time, a circumferentially folded outer rolled mouth 12 is provided on the outer edge of the end of the outer shell 1, and the outer rolled mouth covers and seals the curved edge 32 inside and is fixed to the outer support ring 5; the other is that the outer edge of the current collecting cover 3 is directly circumferentially close to the outer shell 1 and forms a seal, and the outer edge of the outer support ring 5 is directly circumferentially in contact with the outer shell 1 and fixed;

[0058] Step 8: After the inner and outer support rings are fixed to the boss 9 and the housing 1 respectively, the inner end surface of the current collector cover 3 and the outer end surface of the current collector 2 can be sealed tightly, thereby completing the sealing of the lithium battery port.

[0059] The sealing of the end of the lithium battery of the present invention is achieved by a tightly fitting collecting cover, and the connection between the collecting cover and the outer shell is achieved by the inner and outer support rings, that is, the port closing structure is borne by two places respectively. Since the sealing and fixing are manufactured separately, it is only necessary to ensure that the inner support ring and the boss, and the outer support ring and the outer shell can be fixed, and there is no need to ensure the sealing and connection at the same time like circular welding, which greatly reduces the requirements for the welding process; obviously, this structural method is not only simpler in design, but also saves welding time, improves manufacturing efficiency, avoids welding leaks and reduces welding shielding gas pollution to the environment; at the same time, the manufacturing method without circular welding also greatly reduces the manufacturing cost of lithium batteries.

[0060] The above description is only a specific embodiment of the present invention. Those skilled in the art should understand that any structural design similar to this embodiment should be included in the protection scope of the present invention.

Claims

1. A simple lithium battery end sealing structure, comprising a housing (1), a battery cell (11) in the housing, and a current collector (2) mounted at the end of the housing (1), the current collector sealing the battery cell (11) in the housing (1) and forming a conductive connection with the battery cell (11), and a boss (9) protruding outward is provided in the middle of the current collector (2). Features The collector (2) is provided with a collector cover (3) outside, the inner end face of the collector cover is tightly sealed against the outer end face of the collector, the outer end face of the collector cover (3) is provided with an inner support ring (4) and an outer support ring (5), the inner support ring (4) is fixed to the boss (9), and the outer support ring (5) is fixed to the outer shell (1); the outer edge of the collector cover (3) is provided with a curved edge (32) with a circumference bent outward, the curved edge wraps the outer edge of the outer support ring (5) inside, and the outer edge of the end of the outer shell (1) is provided with an outer rolled opening (12) with a circumference folded, the outer rolled opening wraps the curved edge (32) The outer edge of the current collecting cover (3) is directly circumferentially in close contact with the outer shell (1) and forms a seal, and the outer edge of the outer support ring (5) is directly circumferentially in contact with the outer shell (1) and is fixed; the outer circumferential surface of the boss (9) is provided with an inner rolled opening (222) with a circumferential fold, and the inner rolled opening is fixed to the inner support ring (4), or the inner edge of the inner support ring (4) is directly circumferentially in contact with the boss (9) and is fixed; the outer edge of the inner support ring (4) is provided with an outer extension edge (41) extending outward and embedded in the current collecting cover (3); The method for manufacturing the simplified lithium battery end sealing structure comprises the following steps: Step 1: Take the outer shell (1) of the lithium battery and install the battery cell (11) therein; Step 2: Install the current collector (2) at the end of the housing (1) via the insulating ring (6), so that the battery cell (11) is enclosed in the housing (1), and electrical conduction is established between the current collector (2) and the battery cell (11); Step 3: a boss (9) protruding outward and exposed is provided in the middle of the current collector (2); if the end of the lithium battery is a positive terminal, a middle hole (221) penetrating along the axis and a cap (7) sealing the middle hole are provided in the boss (9); if the end of the lithium battery is a negative terminal, the boss (9) is a fully enclosed boss, and a magnetic sheet (10) is provided on the fully enclosed boss; Step 4: a current collecting cover (3) is arranged outside the current collector (2), the inner end surface of the current collecting cover is tightly sealed against the outer end surface of the current collector, and a through hole (31) is provided in the middle of the current collecting cover (3) for exposing the boss (9), and a circumferential inclined surface (34) or a circumferential vertical surface (35) is in sealing contact with the outer surface of the boss; Step 5: Arrange an inner support ring (4) and an outer support ring (5) on the outer end surface of the current collecting cover; Step 6: fix the inner support ring (4) and the boss (9). The fixing structure is divided into two types: one is that the outer circumferential surface of the boss (9) is provided with an inner rolled opening (222) with a circumferential fold, and the inner support ring (4) is fixed by the inner rolled opening; the other is that the inner edge of the inner support ring (4) directly contacts the boss (9) and is fixed; Step 7: fix the outer support ring (5) to the outer shell (1). The fixing structure is also divided into two types; one is that a curved edge (32) with a circumferential outward bend is provided on the outer edge of the current collecting cover (3), and the curved edge circumferentially covers the outer edge of the outer support ring (5), and at the same time, a circumferentially folded outer rolled mouth (12) is provided on the outer edge of the end of the outer shell (1), and the outer rolled mouth covers the curved edge (32) and seals it inside, and is fixed to the outer support ring (5); the other is that the outer edge of the current collecting cover (3) is directly circumferentially in close contact with the outer shell (1) to form a seal, and the outer edge of the outer support ring (5) is directly circumferentially in contact with the outer shell (1) and fixed; Step 8: After the inner and outer support rings are fixed to the boss (9) and the outer shell respectively, the inner end surface of the current collector cover and the outer end surface of the current collector can be sealed and tightly attached, thereby completing the sealing of the lithium battery port.

2. A simplified lithium battery end sealing structure according to claim 1, Features The inner edge of the outer support ring (5) is provided with an inner extension edge (51) extending inwardly and embedded in the current collecting cover (3).

3. A simplified lithium battery end sealing structure according to claim 1, Features A through hole (31) is provided in the middle of the collecting cover (3) for exposing the boss (9), and a circumferential inclined surface (34) or a circumferential vertical surface (35) is in sealing contact with the outer surface of the boss (9) between the hole wall of the through hole and the outer surface of the boss (9).

4. A simplified lithium battery end sealing structure according to claim 1, Features The current collector (2) is composed of a current collecting sheet (21) and a current collecting ring (22), the current collecting ring forming an outwardly protruding boss (9), and the outer edge of the current collecting ring is conductively connected to the inner edge of the current collecting sheet.

5. A simplified lithium battery end sealing structure according to claim 1, Features The boss (9) is provided with a central hole (221) penetrating along the axis, and a cap (7) sealingly covering the central hole is provided in the central hole, or the boss (9) is a fully enclosed boss, and a magnetic sheet (10) is provided on the fully enclosed boss.

6. A simplified lithium battery end sealing structure according to claim 1, Features The outer edge of the current collector (2) is provided with a folded edge (211) that is circumferentially bent inwards, and an insulating ring (6) is provided between the folded edge and the outer shell.

7. A simplified lithium battery end sealing structure according to claim 6, Features A rolling groove (13) is provided on the outer circumferential surface of the housing (1), and the insulating ring (6) is positioned and fixed in the housing (1) by the rolling groove, or the outer support ring (5) squeezes the insulating ring (6) through the current collecting cover (3), and positions and fixes the insulating ring in the housing (1).

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