Novel detachable lithium battery pack structure

Abstract

The novel detachable lithium battery pack structure comprises a first battery module, a second battery module, a BMS (battery management system) and a display screen, the first battery module and the second battery module are positioned on two sides below the BMS, and the display screen is positioned on the wall surface above the BMS; the first battery module comprises a bracket A, a plurality of lithium ion cells, a bracket B and a mylar, the plurality of lithium ion cells are positioned in the middle of the first battery module, the bracket A and the bracket B are respectively positioned on two sides of the lithium ion cells, a series nickel strap A is arranged between the mylar and the bracket A, and a series nickel strap B and a series nickel strap C are arranged between the bracket B and the mylar; the second battery module comprises a support C, a lithium ion battery cell, a support B and a mylar, the support C and the support B are located on the two sides of the lithium ion battery cell respectively, and a positive and negative nickel strap is arranged between the mylar and the support B; according to the utility model, the BMS is convenient to disassemble, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a lithium-ion battery structure in which a battery pack and a BMS are connected by a pressing sheet and bolts for fixing, and the BMS is convenient for disassembly. The battery has a display screen, CAN and 485 communications. Background Art

[0002] Due to the influence of the current market environment, new energy sources are gradually being paid attention to by the public, especially the advantages of lithium batteries such as high energy density and high number of cycles are gradually being applied to various fields. Compared with lead-acid batteries, the advantages of lithium batteries are more obvious. Lead-acid replacement projects are being carried out in full swing in various fields, especially the demand for commonly used 12V battery packs of various models has increased sharply. The market demand for lithium battery packs is becoming more and more diversified, and higher requirements are being placed on lithium battery manufacturers. How to quickly and efficiently produce lithium battery packs that meet market demand is the demand that the market currently puts forward to lithium battery manufacturers.

[0003] At present, lithium-ion battery packs mainly use straight-line and staggered structures between battery packs to achieve the fixation between individual battery cells. With the customization of more and more lithium battery packs, a bracket structure has been developed to better fix the battery cells. However, due to the limitations of lead-acid shells, BMS is mostly fixed on the side or front of the battery pack, and soldering is used to meet the conductivity requirements of large currents.

[0004] Currently, there are only two ways to connect lithium-ion batteries to protection boards. One is to directly connect the battery pack B+ / B- to the protection board using soldering by extending the nickel strip. The soldering process has high requirements and it is difficult to maintain the product in the later stage. The other is to directly weld one end of the multi-strand silicone wire harness to the B+ / B- pole surface of the battery pack and connect the other end to the protection board, which will cause a waste of space and complicated wiring.

[0005] In view of the above disadvantages, the market is currently in urgent need of a battery pack structure that can achieve high current conductivity and facilitate subsequent maintenance through the close cooperation of the upper and lower pressure plates and bolts between the BMS and the battery pack B+ / B-. Summary of the invention

[0006] The utility model provides a novel detachable lithium battery pack structure, which solves the problems of design defects and low production efficiency existing in current batteries.

[0007] To achieve the above object, the utility model provides the following technical solutions: a novel detachable lithium battery pack structure, comprising a first battery module, a second battery module, a BMS and a display screen, wherein the first battery module and the second battery module are located on both sides below the BMS, and the display screen is located on the wall above the BMS;

[0008] The first battery module comprises a bracket A, a lithium-ion battery cell, a bracket B and a Mylar sheet, a plurality of the lithium-ion battery cells are located in the middle of the first battery module, the bracket A and the bracket B are respectively located on both sides of the lithium-ion battery cell, the Mylar sheets are respectively located on the outermost sides of the first battery module, and a series nickel strip A is provided between the Mylar sheet and the bracket A close to the outer side, and a series nickel strip B and a series nickel strip C are provided between the bracket B and the Mylar sheet close to the inner side;

[0009] The second battery module includes a bracket C, a lithium-ion battery cell, a bracket B and a Mylar sheet. Several of the lithium-ion battery cells are located in the middle of the second battery module. The bracket C and the bracket B are respectively located on both sides of the lithium-ion battery cells. The Mylar sheets are respectively located on the outermost sides of the second battery module, and positive and negative nickel strips are provided between the Mylar sheet and the bracket B close to the outer side.

[0010] Preferably, first copper studs are respectively provided on both sides of the upper end of the bracket A for fixing to each other with the BMS bracket at the upper end, first battery pack fixing columns are respectively provided on the inner wall surfaces at both ends of the bracket A, and M5 copper studs are embedded inside the columns of the battery pack fixing columns for fixing the lithium-ion battery cells, and first waist holes are respectively provided on the outer ends of the first copper studs for fixing the assembled battery pack to the battery shell.

[0011] Preferably, second copper studs are respectively provided on both sides of the upper end of the bracket C for fixing to each other with the BMS bracket at the upper end, second battery pack fixing columns are respectively provided on the inner wall surfaces at both ends of the bracket A, and M5 copper studs are embedded inside the columns of the second battery pack fixing columns for fixing the lithium-ion battery cells, and second waist holes are respectively provided on the outer ends of the second copper studs for fixing the assembled battery pack to the battery shell.

[0012] Preferably, an upper pressing plate and a lower pressing plate are respectively provided on one side of the BMS surface, and the upper pressing plate and the lower pressing plate are respectively located at the upper and lower ends of the BMS, and the upper pressing plate is provided with a plurality of first through holes for convenient insertion of bolts; threaded holes are provided on the surface of the lower pressing plate, and are fixed by bolts passing through the first through holes in the upper pressing plate; and a limiting hole is also provided on the surface of the lower pressing plate.

[0013] Preferably, first bosses are respectively provided on both sides of the upper end of the bracket B, which are used to support the BMS and prevent the BMS from contacting the lithium-ion battery cell; a plurality of second bosses are provided on the upper end surface of the bracket B, which are limited by the cooperation of the second bosses and the limiting holes; a plurality of third bosses are provided on the inner side surface of the bracket B, which are used to limit the nickel sheet; an isolation line is provided in the middle position of the bracket B, which is used to physically isolate nickel strips of different polarities to prevent short circuits caused by contact between nickel strips of different polarities; second through holes are respectively provided at both ends of the other side wall of the bracket B, and the battery pack is fixed by the cooperation of the second through holes and bolts; third waist holes are respectively provided on the outer sides of the first bosses, which are used to assemble the battery pack and fix it to the battery shell.

[0014] Preferably, a plurality of first circular holes are provided on the side surface of the series nickel strip A, and the first circular holes are matched with the limiting holes between the brackets to limit the position of the nickel strip; a first externally exposed nickel strip is provided on the upper end of the series nickel strip A for collecting voltage.

[0015] Preferably, a plurality of second circular holes are provided on the side surfaces of the positive and negative nickel strips, which are used to limit the position of the nickel strips through the concave-convex cooperation between the second circular holes and the limiting holes between the brackets; a plurality of fixing circular holes are provided on the upper end surfaces of the positive and negative nickel strips, which are fixed to the BMS by cooperating with bolts.

[0016] Preferably, the series nickel strip B and the series nickel strip C are in a mirror image relationship, and a plurality of third circular holes are provided on the side surfaces of the series nickel strip B and the series nickel strip C, which are used to limit the nickel strip through the concave-convex cooperation with the limiting holes between the brackets; a nickel strip fold is provided between the series nickel strip B and the series nickel strip C, which is used for folding the nickel strip when the battery pack is folded; a second externally exposed nickel strip is provided on the upper ends of the series nickel strip B and the series nickel strip C, respectively, for voltage collection.

[0017] Preferably, a third through hole is respectively provided on both sides of the BMS for fixing the BMS on the bracket; a P+ wiring harness position is provided on the surface of the BMS for connecting to the P+ pole of the lead-acid shell; a B+ conductive electrode is provided on one side of the surface of the BMS, in which a small hole is provided for connecting to the battery pack B+; a B- conductive electrode is provided on the other side of the surface of the BMS, in which a small hole is provided, which is fixed by upper and lower pressure plates for connecting to the battery pack B-; a B1 welding point and a B2 welding point are respectively provided on the surface of the BMS for voltage collection at B1 and B2 of the battery pack respectively; a communication terminal seat is also provided on the surface of the BMS for supporting RS232 and 485 communications; a P- wiring harness position is provided on the surface of the BMS near the B2 welding point for connecting to the P- pole of the lead-acid shell; a display screen communication terminal seat is symmetrically provided on the surface of the BMS on the other side of the communication terminal seat for displaying information such as the battery pack power; an NTC position is provided on one side of the display screen communication terminal seat for battery pack temperature collection.

[0018] Compared with the prior art, the utility model has the following beneficial effects: the utility model sets up a BMS and a battery pack B+ / B-, and achieves a battery pack structure with high current conductivity and convenient later maintenance through the close cooperation of the upper and lower pressure plates and bolts, while improving production efficiency and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention.

[0020] In the attached picture:

[0021] Figure 1 This is a schematic diagram of the structure of the battery pack of the utility model after spot welding and assembly;

[0022] Figure 2 This is a schematic diagram of the explosion of the battery pack of the utility model after spot welding;

[0023] Figure 3 It is a structural schematic diagram of the bracket A of the utility model;

[0024] Figure 4 It is a structural schematic diagram of the bracket B of the utility model;

[0025] Figure 5 It is a structural schematic diagram of the bracket C of the utility model;

[0026] Figure 6 This is a schematic diagram of the structure of the serially connected nickel strip A of the utility model;

[0027] Figure 7 It is a schematic diagram of the structure of the serial nickel strip B and the serial nickel strip C of the utility model;

[0028] Figure 8 This is a schematic diagram of the structure of the positive and negative nickel strips of the utility model;

[0029] Fig. 9 It is a structural schematic diagram of the BMS of the utility model;

[0030] Numbers in the figure: 1. Nickel strip A in series; 101. First round hole; 102. First exposed nickel strip; 11. Mylar sheet; 12. Bracket B; 1201. First boss; 1202. Second boss; 1203. Third boss; 1204. Isolation line; 1205. Second through hole; 1206. Third waist hole; 13. Lithium-ion battery cell; 14. Bracket C; 1401. Second copper stud; 1402. Second battery pack fixing column; 1403. Second waist hole; 15. Bracket A; 1501. First copper stud; 1502. First battery pack fixing column; 1503. First waist hole; 2. Nickel strip in series B; 201, third round hole; 202, nickel belt fold; 203, second exposed nickel belt; 3, series nickel belt C; 4, display screen; 5, BMS; 501, third through hole; 502, P+ wiring harness; 503, B+ conductive electrode; 504, B- conductive electrode; 505, B1 welding point; 506, communication terminal seat; 507, B2 welding point; 508, P- wiring harness; 509, display screen communication terminal seat; 510, NTC; 6, bolt; 7, upper pressure plate; 8, lower pressure plate; 801, threaded hole; 802, limit hole; 9, positive and negative nickel belts; 901, fixed round hole; 902, second round hole. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0032] Example: Figure 1 and Figure 2 As shown, a novel detachable lithium battery pack structure includes a first battery module, a second battery module, a BMS5 and a display screen 4, wherein the first battery module and the second battery module are located on both sides below the BMS5, and the display screen 4 is located on the wall above the BMS5;

[0033] The first battery module includes a bracket A15, a lithium-ion battery cell 13, a bracket B12 and a Mylar sheet 11, a plurality of the lithium-ion battery cells 13 are located in the middle of the first battery module, the bracket A15 and the bracket B12 are located on both sides of the lithium-ion battery cell 13, the Mylar sheet 11 is located at the outermost side of the first battery module, and a series nickel strip A1 is provided between the Mylar sheet 11 and the bracket A15 near the outer side, and a series nickel strip B2 and a series nickel strip C3 are provided between the bracket B12 and the Mylar sheet 11 near the inner side;

[0034] The second battery module includes a bracket C14, a lithium-ion battery cell 13, a bracket B12 and a Mylar sheet 11. Several of the lithium-ion battery cells 13 are located in the middle of the second battery module, the bracket C14 and the bracket B12 are respectively located on both sides of the lithium-ion battery cell 13, the Mylar sheet 11 is respectively located at the outermost side of the second battery module, and a positive and negative nickel strip 9 is provided between the Mylar sheet 11 close to the outside and the bracket B12.

[0035] Among them, the material used for bracket A15, bracket B12, and bracket C14 is ABS, the flame retardant grade is V0, and the color is black. After the battery pack is spot-welded, the Mylar sheet 11 is attached to the back of the battery pack to provide insulation protection for the battery pack.

[0036] Among them, Figure 3 As shown, first copper studs 1501 are respectively provided on both sides of the upper end of the bracket A15, and M3 first copper studs are pre-embedded with a depth of 6 mm, which are used to fix with the BMS5 bracket at the upper end to ensure the firmness of the BMS5. First battery pack fixing columns 1502 are respectively provided on the inner wall surfaces at both ends of the bracket A15, and M5 copper studs are embedded inside the columns of the battery pack fixing columns to fix the two battery packs and prevent the battery packs from moving and affecting the performance of the protection board. The outer ends of the first copper studs 1501 are respectively provided with first waist holes 1503 for fixing the assembled battery pack to the battery shell.

[0037] Among them, Figure 5 As shown, second copper studs 1401 are respectively provided on both sides of the upper end of the bracket C14, and pre-embedded M3 copper studs with a depth of 6 mm are used to fix with the BMS5 bracket at the upper end to ensure the firmness of the BMS5; the inner wall surfaces at both ends of the bracket A15 are respectively provided with second battery pack fixing columns 1402, and the inside of the second battery pack fixing columns 1402 is inlaid with M5*130 copper studs for fixing the lithium-ion battery cells 13, and the outer ends of the second copper studs 1401 are respectively provided with second waist holes 1403 for fixing the assembled battery pack to the battery shell.

[0038] Among them, Figure 4As shown, first bosses 1201 are respectively provided on both sides of the upper end of the bracket B12 for supporting the BMS5 to prevent the BMS5 from contacting the lithium-ion battery cell 13; the upper end surface of the bracket B12 is provided with a plurality of second bosses 1202 with a diameter of 4 mm, and the height of the second bosses 1202 is 5 mm, and the second bosses 1202 and the limiting holes 802 cooperate with each other to limit the position, and the inner side surface of the bracket B12 is provided with a plurality of third bosses 1203 with a diameter of 3 mm and a height of 1 mm for limiting the position with the nickel sheet. An isolation line 1204 with a width of 2mm and a height of 2mm is provided at the intermediate position, and the isolation line 1204 is used to physically isolate the nickel strips of different polarities to prevent short circuit caused by contact between the nickel strips of different polarities; second through holes 1205 are respectively provided at both ends of the other side wall of the bracket B12, and the battery pack is fixed by the cooperation of the second through holes 1205 and the bolts 6; third waist holes 1206 are respectively provided on the outer side of the first boss 1201, and the third waist holes 1206 are used to assemble the battery pack and fix it to the battery shell.

[0039] Among them, Figure 6 As shown, a plurality of first circular holes 101 with a diameter of 3 mm are provided on the side surface of the series nickel strip A1, and the first circular holes 101 are matched with the limiting holes 802 between the brackets to limit the position of the nickel strip; a first externally exposed nickel strip 102 is provided on the upper end of the series nickel strip A1 for collecting voltage.

[0040] Among them, Figure 8 As shown, the side surfaces of the positive and negative nickel strips 9 are provided with a plurality of second circular holes 902 with a diameter of 3 mm, and the second circular holes 902 are used to limit the nickel strips through the concave-convex cooperation with the limiting holes 802 between the brackets; the upper end surfaces of the positive and negative nickel strips 9 are provided with a plurality of fixing circular holes 901 with a diameter of 5 mm, which are fixed to the BMS5 by cooperating with the M5*14mm bolts 6.

[0041] Among them, Figure 7 As shown, the series-connected nickel strip B2 and the series-connected nickel strip C3 are in a mirror image relationship, and the side surfaces of the series-connected nickel strip B2 and the series-connected nickel strip C3 are provided with a plurality of third circular holes 201 with a diameter of 3 mm, and the third circular holes 201 are matched with the limiting holes 802 between the brackets to limit the position of the nickel strip; a nickel strip fold 202 is provided between the series-connected nickel strip B2 and the series-connected nickel strip C3, which is used for folding the nickel strip when the battery pack is folded; the upper ends of the series-connected nickel strip B2 and the series-connected nickel strip C3 are respectively provided with second externally exposed nickel strips 203 for voltage collection.

[0042] Among them, Fig. 9As shown, an upper pressing plate 7 and a lower pressing plate 8 are respectively provided on one side of the surface of BMS5, and the upper pressing plate 7 and the lower pressing plate 8 are respectively located at the upper and lower ends of the BMS5, and the upper pressing plate 7 is a nickel-plated steel plate with a thickness of 3 mm; and the upper pressing plate 7 is provided with a plurality of first through holes with a diameter of 4 MM, which are convenient for the bolt 6 to penetrate; the surface of the lower pressing plate 8 is provided with an M5 threaded hole 801, and the bolt 6 is inserted into the first through hole in the upper pressing plate 7 for fixing; the surface of the lower pressing plate 8 is also provided with a limiting hole 802 with a diameter of 4 mm, and the boss of the bracket B12 can be inserted to play a limiting role; third through holes 501 with a diameter of 3 mm are respectively provided on both sides of the BMS5, which are used to fix the BMS5 on the bracket; a P+ wiring harness 502 position is provided on the surface of the BMS5, which is used to connect with the P+ pole of the lead-acid shell; a B+ conductive electrode 503 is provided on one side of the surface of the BMS5, which includes 4 diameters It is a 5mm small hole for connecting to the battery pack B+; a B- conductive electrode 504 is provided on the other side of the BMS5 surface, which includes 4 small holes with a diameter of 5mm, fixed by upper and lower pressing plates 8, and is used to connect to the battery pack B-; the BMS5 surface is respectively provided with B1 welding point 505 and B2 welding point 507, which are used for voltage collection at B1 and B2 of the battery pack respectively; the BMS5 surface is also provided with a communication terminal seat 506, which supports RS232 and 485 communications; a P- wiring harness 508 position is provided on the BMS5 surface near the B2 welding point 507, which is used to connect to the P-pole of the lead-acid shell; a display screen communication terminal seat 509 is symmetrically provided on the BMS5 surface on the other side of the communication terminal seat 506, which is used to display information such as battery pack power; an NTC510 position is provided on one side of the display screen communication terminal seat 509, which is used to collect battery pack temperature.

[0043] Specific steps:

[0044] Step 1: Assemble the first battery module, load 60 lithium iron phosphate battery cells 13 into the bracket A15 and then assemble the bracket B12.

[0045] Step 2: Assemble the second battery module, load 60 lithium iron phosphate battery cells 13 into the bracket C14 and then assemble the bracket B12.

[0046] Step 3: spot welding the first battery module and the second battery module, and spot welding nickel strips use series nickel strip A1, series nickel strip B2, series nickel strip C3, and positive and negative nickel strips 9.

[0047] Step 4: Stick the Mylar sheet 11 on the front and back of the first battery module and the second battery module to avoid safety problems.

[0048] Step 5: Assemble the protection board. The protection board is fixed in the reserved holes with four screws. Crimping the protection board B+ and B-, welding the protection board and the nickel strip to the outside, using nickel-plated gaskets as carriers for the power supply end of the protection board and the battery, connecting the protection board and the nickel sheet of the battery pack to avoid direct connection between the protection board and the nickel sheet of the battery pack through soldering, which is conducive to the later disassembly and maintenance of the protection board.

[0049] Step 6: Use the communication harness to connect the protection board and the display screen 4.

[0050] Step 7: Place the NTC510 inside the battery cell and secure it with tape.

[0051] Finally, it should be noted that the above description is only a preferred example of the present utility model and is not intended to limit the present utility model. Although the present utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A novel detachable lithium battery pack structure, characterized in that: It includes a first battery module, a second battery module, a BMS and a display screen, wherein the first battery module and the second battery module are located on both sides below the BMS, and the display screen is located on the wall above the BMS; The first battery module comprises a bracket A, a lithium-ion battery cell, a bracket B and a Mylar sheet, a plurality of the lithium-ion battery cells are located in the middle of the first battery module, the bracket A and the bracket B are respectively located on both sides of the lithium-ion battery cell, the Mylar sheets are respectively located on the outermost sides of the first battery module, and a series nickel strip A is provided between the Mylar sheet and the bracket A close to the outer side, and a series nickel strip B and a series nickel strip C are provided between the bracket B and the Mylar sheet close to the inner side; The second battery module includes a bracket C, a lithium-ion battery cell, a bracket B and a Mylar sheet. Several of the lithium-ion battery cells are located in the middle of the second battery module. The bracket C and the bracket B are respectively located on both sides of the lithium-ion battery cells. The Mylar sheets are respectively located on the outermost sides of the second battery module, and positive and negative nickel strips are provided between the Mylar sheet and the bracket B close to the outer side.

2. A novel detachable lithium battery pack structure according to claim 1, characterized in that: First copper studs are respectively provided on both sides of the upper end of the bracket A for fixing to each other with the BMS bracket at the upper end; first battery pack fixing columns are respectively provided on the inner wall surfaces at both ends of the bracket A, and M5 copper studs are embedded inside the columns of the battery pack fixing columns for fixing the lithium-ion battery cells; first waist holes are respectively provided on the outer ends of the first copper studs for fixing the assembled battery pack to the battery shell.

3. The novel detachable lithium battery pack structure according to claim 1 is characterized in that: Second copper studs are respectively provided on both sides of the upper end of the bracket C for fixing to the BMS bracket at the upper end. Second battery pack fixing columns are respectively provided on the inner wall surfaces at both ends of the bracket A, and M5 copper studs are embedded inside the columns of the second battery pack fixing columns for fixing the lithium-ion battery cells. Second waist holes are respectively provided on the outer ends of the second copper studs for fixing the assembled battery pack to the battery shell.

4. The novel detachable lithium battery pack structure according to claim 1, characterized in that: An upper pressing plate and a lower pressing plate are respectively provided on one side of the BMS surface, and the upper pressing plate and the lower pressing plate are respectively located at the upper and lower ends of the BMS, and the upper pressing plate is provided with a plurality of first through holes for convenient insertion of bolts; threaded holes are provided on the surface of the lower pressing plate, and are fixed by bolts passing through the first through holes in the upper pressing plate; a limiting hole is also provided on the surface of the lower pressing plate.

5. A novel detachable lithium battery pack structure according to claim 4, characterized in that: A first boss is respectively provided on both sides of the upper end of the bracket B, which is used to support the BMS and prevent the BMS from contacting the lithium-ion battery cell; a plurality of second bosses are provided on the upper end surface of the bracket B, and the second bosses and the limiting holes are limited by mutual cooperation; a plurality of third bosses are provided on the inner side surface of the bracket B, which are used to limit the nickel sheet; an isolation line is provided in the middle position of the bracket B, and the isolation line is used to physically isolate nickel strips of different polarities to prevent short circuits caused by contact between nickel strips of different polarities; second through holes are respectively provided at both ends of the other side wall of the bracket B, and the battery pack is fixed by mutual cooperation with bolts through the second through holes; third waist holes are respectively provided on the outer sides of the first bosses, and the third waist holes are used to assemble the battery pack and fix it to the battery shell.

6. A novel detachable lithium battery pack structure according to claim 5, characterized in that: The side surface of the series nickel strip A is provided with a plurality of first circular holes, which are used to limit the position of the nickel strip through the concave-convex cooperation with the limiting holes between the brackets; the upper end of the series nickel strip A is provided with a first externally exposed nickel strip for voltage collection.

7. A novel detachable lithium battery pack structure according to claim 6, characterized in that: A plurality of second circular holes are provided on the side surfaces of the positive and negative nickel strips, which are used to limit the position of the nickel strips through the concave-convex cooperation with the limiting holes between the brackets; a plurality of fixing circular holes are provided on the upper end surfaces of the positive and negative nickel strips, which are fixed to the BMS by cooperating with bolts.

8. A novel detachable lithium battery pack structure according to claim 7, characterized in that: The series nickel strip B and the series nickel strip C are in a mirror image relationship. The side surfaces of the series nickel strip B and the series nickel strip C are provided with a plurality of third circular holes, which are used to limit the nickel strip through the concave-convex cooperation with the limiting holes between the brackets; a nickel strip fold is provided between the series nickel strip B and the series nickel strip C, which is used for folding the nickel strip when the battery pack is folded; the upper ends of the series nickel strip B and the series nickel strip C are respectively provided with a second externally exposed nickel strip for voltage collection.

9. A novel detachable lithium battery pack structure according to claim 8, characterized in that: A third through hole is provided on both sides of the BMS for fixing the BMS on the bracket; a P+ harness position is provided on the surface of the BMS for connecting to the P+ pole of the lead-acid shell; a B+ conductive electrode is provided on one side of the surface of the BMS, in which a small hole is provided for connecting to the battery pack B+; a B- conductive electrode is provided on the other side of the surface of the BMS, in which a small hole is provided, which is fixed by upper and lower pressure plates for connecting to the battery pack B-; a B1 welding point and a B2 welding point are provided on the surface of the BMS for voltage collection at B1 and B2 of the battery pack respectively; a communication terminal seat is also provided on the surface of the BMS for supporting RS232 and 485 communications; a P- harness position is provided on the surface of the BMS near the B2 welding point for connecting to the P- pole of the lead-acid shell; a display screen communication terminal seat is provided on the surface of the BMS symmetrically to the other side of the communication terminal seat for displaying information such as the battery pack power; an NTC position is provided on one side of the display screen communication terminal seat for battery pack temperature collection.

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