Improved foil coil structure and manufacturing method thereof

Abstract

The invention relates to the technical field of coil structures, in particular to an improved foil coil structure and a manufacturing method thereof. An upper winding and a lower winding are wound on the iron core column; the upper winding is formed by winding an upper coil foil tape and upper interlayer insulation paper which are attached to each other along the top of the iron core column; the lower winding is formed by winding a lower coil foil tape and lower interlayer insulation paper which are attached to each other along the bottom of the iron core column; the upper coil foil tape and the lower coil foil tape are connected in series, and the sum of the number of turns of the upper coil foil tape and the number of turns of the lower coil foil tape which are connected in series is the total number of turns of the improved foil coil structure; the thickness of the upper coil foil tape is the same as that of the lower coil foil tape; and the width of the upper coil foil tape is greater than that of the lower coil foil tape. The width of the upper coil foil tape is larger than that of the lower coil foil tape, so that the temperature of the upper winding can be reduced, the temperature rise of the upper winding is basically close to that of the lower winding, the hot-spot temperature rise of the coil is reduced, and the product reliability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coil structures, and in particular to an improved foil-wound coil structure and a manufacturing method thereof. Background Art

[0002] In today's fierce competition in the transformer industry, small size, high power density and low cost have become the key goals pursued by many transformer manufacturers and front-end customers in the development of new products. In the process of striving towards this goal, improving the temperature resistance level of the product has become an effective technical path. With the gradual increase in the allowable temperature rise of the product, the physical size of the transformer can be further reduced, and the amount of material used can be reduced accordingly. This not only conforms to the development trend of miniaturization and lightweight of modern electronic products, but also can effectively reduce production costs and improve the market competitiveness of products.

[0003] However, in practice, a significant bottleneck problem has gradually emerged. Generally speaking, the temperature resistance level of insulating materials is positively correlated with the unit price, that is, the higher the temperature resistance of the insulating material, the more expensive its unit price. This makes cost control a huge challenge while pursuing high temperature resistance levels to achieve product miniaturization. Therefore, exploring how to reduce the amount of insulating materials while ensuring that the performance of the entire machine is not affected has become one of the important research directions for reducing product costs.

[0004] At present, there have been some technical attempts to solve this problem. For example, the Chinese invention patent with patent application number 2024103286983 adopts the method of halving the width of the foil, doubling the thickness, and winding 2 turns in one layer to achieve the purpose of halving the layer insulation. In this way, without changing the size and performance of the whole machine, the amount of insulating paper is successfully saved, and the cost is reduced to a certain extent. However, this technology is not perfect. In actual applications, it is found that when the coil is divided into two sections, the width of the upper foil is the same as the width of the lower foil, which will cause the temperature rise of the upper coil to be significantly higher than that of the lower coil. This phenomenon shows that the existing design of equal width of the upper and lower coil foils is not the optimal solution, and there is still room for further optimization. Summary of the invention

[0005] The object of the present invention is to provide an improved foil-wound coil structure and a manufacturing method thereof in view of the above-mentioned deficiencies in the prior art.

[0006] The object of the present invention is achieved by the following technical scheme: an improved foil-wound coil structure, comprising an iron core column; the iron core column is wound with an upper winding and a lower winding; the upper winding is formed by winding an upper coil foil tape and an upper interlayer insulating paper that are bonded to each other along the top of the iron core column; the lower winding is formed by winding a lower coil foil tape and a lower interlayer insulating paper that are bonded to each other along the bottom of the iron core column;

[0007] The upper coil foil strip is connected in series with the lower coil foil strip, and the sum of the turns of the upper coil foil strip and the turns of the lower coil foil strip after the series connection is the total number of turns of the improved foil-wound coil structure;

[0008] The thickness of the upper coil foil is the same as that of the lower coil foil; the width of the upper coil foil is greater than that of the lower coil foil.

[0009] The present invention is further configured such that a ventilation gap is provided between the upper winding and the lower winding.

[0010] The present invention is further configured such that the upper winding is provided with an upper air duct; and the lower winding is provided with a lower air duct.

[0011] The present invention is further configured such that the width of the upper interlayer insulating paper is greater than the width of the upper coil foil; and the width of the lower interlayer insulating paper is greater than the width of the lower coil foil.

[0012] The present invention is further configured such that an upper inlet line row is provided on the inner side of the front end of the top of the core column; a lower inlet line row is provided on the inner side of the front end of the bottom of the core column;

[0013] An upper outgoing wire row is provided on the outer front end of the top of the core column; the upper outgoing wire row passes through the lower winding and extends to the bottom of the core column; a lower outgoing wire row is provided on the outer front end of the bottom of the core column; the lower outgoing wire row passes through the upper winding and extends to the top of the core column;

[0014] The upper outgoing line row is connected in series with the lower incoming line row;

[0015] The upper coil foil is arranged between the upper incoming wire row and the upper outgoing wire row, and is respectively welded to the upper incoming wire row and the upper outgoing wire row before being led out; the lower coil foil is arranged between the lower incoming wire row and the lower outgoing wire row, and is respectively welded to the lower incoming wire row and the lower outgoing wire row before being led out.

[0016] The present invention is further configured such that the bottom of the upper outlet row and the top of the lower outlet row are both covered with insulating tape.

[0017] The present invention is further configured such that the bottom of the upper outgoing wire row and the top of the lower outgoing wire row are both covered with insulating paper pads.

[0018] The present invention is further configured that the iron core column includes a first core column, a second core column and a third core column; the first core column, the second core column and the third core column are all provided with an upper winding and a lower winding;

[0019] An upper cross iron is arranged between the top of the first core column, the top of the second core column and the top of the third core column; a lower cross iron is arranged between the bottom of the first core column, the bottom of the second core column and the bottom of the third core column.

[0020] A method for manufacturing an improved foil wound coil structure comprises the following steps:

[0021] S1, laminating the upper coil foil tape and the upper interlayer insulating paper together, and laminating the lower coil foil tape and the lower interlayer insulating paper together;

[0022] S2, winding the upper coil foil and the upper interlayer insulating paper along the top of the core column and winding the lower coil foil and the lower interlayer insulating paper along the bottom of the core column at the same time;

[0023] S3, connecting the end of the upper coil foil strip with the beginning of the lower coil foil strip in series.

[0024] The present invention is further configured that the selection of the width of the upper coil foil and the width of the lower coil foil comprises the following steps:

[0025] A1. Measure the height of the top surface of the lower coil foil and the height of the top surface of the upper coil foil;

[0026] A2. Measure the temperature rise of the upper winding and the temperature rise of the lower winding after current is passed;

[0027] A3. Calculate the unit heat load of the upper coil foil and the unit heat load of the lower coil foil according to the formula T=k1*(H / 1000)^0.2*q^0.8; where T is the temperature rise, k1 is the temperature rise coefficient, H is the height of the top surface of the coil foil, and q is the unit heat load;

[0028] A4. Convert the unit heat load of the upper coil foil into the coil temperature rise value T1 and convert the unit heat load of the lower coil foil into the coil temperature rise value T2. Based on the principle of T1=T2, calculate the width of the upper coil foil and the width of the lower coil foil.

[0029] Beneficial effects of the present invention: The present invention can reduce the temperature of the upper winding by making the width of the upper coil foil greater than that of the lower coil foil, making the temperature rise of the upper winding and the lower winding basically close, reducing the hot spot temperature rise of the coil and improving product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0031] Figure 1 is a perspective view of the present invention;

[0032] Figure 2 is a top view of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the three core columns of the present invention after being combined;

[0034] Figure 4 It is a structural schematic diagram of another viewing angle after the three core columns of the present invention are combined;

[0035] Figure 5 is a table for selecting the width of the upper coil foil and the width of the lower coil foil of the present invention;

[0036] Among them: 1. Iron core column; 2. Upper winding; 21. Upper coil foil; 22. Upper interlayer insulating paper; 3. Lower winding; 31. Lower coil foil; 32. Lower interlayer insulating paper; 4. Ventilation gap; 51. Upper air duct; 52. Lower air duct; 61. Upper incoming wire row; 62. Upper outgoing wire row; 71. Lower incoming wire row; 72. Lower outgoing wire row; 81. Insulating tape; 82. Insulating paper pad; 91. First core column; 92. Second core column; 93. Third core column; 94. Upper cross iron; 95. Lower cross iron. DETAILED DESCRIPTION

[0037] The present invention is further described in conjunction with the following examples.

[0038] Depend on Figures 1 to 5 It can be seen that the improved foil-wound coil structure described in this embodiment includes an iron core column 1; the iron core column 1 is wound with an upper winding 2 and a lower winding 3; the upper winding 2 is formed by winding an upper coil foil tape 21 and an upper interlayer insulating paper 22 that are attached to each other along the top of the iron core column 1; the lower winding 3 is formed by winding a lower coil foil tape 31 and a lower interlayer insulating paper 32 that are attached to each other along the bottom of the iron core column 1;

[0039] The upper coil foil strip 21 and the lower coil foil strip 31 are connected in series, and the sum of the turns of the upper coil foil strip 21 and the turns of the lower coil foil strip 31 after the series connection is the total number of turns of the improved foil-wound coil structure;

[0040] The thickness of the upper coil foil 21 is the same as that of the lower coil foil 31 ; the width of the upper coil foil 21 is greater than that of the lower coil foil 31 .

[0041] Specifically, in the improved foil-wound coil structure described in this embodiment, the upper winding 2 can be wound together with the lower winding 3 during production, which can effectively improve the overall production efficiency. In addition, by making the width of the upper coil foil 21 larger than the width of the lower coil foil 31, the temperature of the upper winding 2 can be reduced, making the temperature rise of the upper winding 2 and the lower winding 3 basically close, reducing the hot spot temperature rise of the coil and improving product reliability.

[0042] In the improved foil-wound coil structure described in this embodiment, a ventilation gap 4 is provided between the upper winding 2 and the lower winding 3. The above arrangement can improve the overall heat dissipation function.

[0043] In the improved foil-wound coil structure described in this embodiment, the upper winding 2 is provided with an upper air duct 51, and the lower winding 3 is provided with a lower air duct 52. The above arrangement can improve the overall heat dissipation function.

[0044] In the improved foil-wound coil structure described in this embodiment, the width of the upper interlayer insulating paper 22 is greater than the width of the upper coil foil 21; the width of the lower interlayer insulating paper 32 is greater than the width of the lower coil foil 31. Through the above arrangement, the upper and lower sides of the upper interlayer insulating paper 22 are respectively beyond the upper and lower sides of the upper coil foil 21, and the upper and lower sides of the lower interlayer insulating paper 32 are respectively beyond the upper and lower sides of the lower coil foil 31, so that the insulation effect can be effectively achieved.

[0045] An improved foil-wound coil structure described in this embodiment is characterized in that an upper incoming wire row 61 is provided on the inner side of the front end of the top of the core column 1; a lower incoming wire row 71 is provided on the inner side of the front end of the bottom of the core column 1; an upper outgoing wire row 62 is provided on the outer side of the front end of the top of the core column 1; the upper outgoing wire row 62 passes through the lower winding 3 and extends to the bottom of the core column 1; a lower outgoing wire row 72 is provided on the outer side of the front end of the bottom of the core column 1; the lower outgoing wire row 72 passes through the upper winding 2 and extends to the top of the core column 1; the upper outgoing wire row 62 is connected in series with the lower incoming wire row 71; the upper coil foil strip 21 is provided between the upper incoming wire row 61 and the upper outgoing wire row 62, and is respectively welded to the upper incoming wire row 61 and the upper outgoing wire row 62 and then led out; the lower coil foil strip 31 is provided between the lower incoming wire row 71 and the lower outgoing wire row 72, and is respectively welded to the lower incoming wire row 71 and the lower outgoing wire row 72 and then led out.

[0046] Specifically, through the above arrangement, the upper winding 2 and the lower winding 3 are wound simultaneously and then connected at the upper outgoing wire row 62 and the lower incoming wire row 71 , so that the end of the upper winding 2 and the beginning of the lower winding 3 are connected in series.

[0047] In the improved foil-wound coil structure described in this embodiment, the bottom of the upper outgoing wire row 62 and the top of the lower outgoing wire row 72 are both covered with insulating tape 81. The above arrangement facilitates insulation between the upper outgoing wire row 62 and the lower winding 3, and facilitates insulation between the lower outgoing wire row 72 and the upper winding 2.

[0048] In the improved foil-wound coil structure described in this embodiment, the bottom of the upper outgoing wire row 62 and the top of the lower outgoing wire row 72 are both covered with an insulating paper pad 82. The above arrangement can improve the insulation performance between the upper outgoing wire row 62 and the lower winding 3, and can improve the insulation performance between the lower outgoing wire row 72 and the upper winding 2.

[0049] An improved foil-wound coil structure described in this embodiment, the iron core column 1 includes a first core column 91, a second core column 92 and a third core column 93; the first core column 91, the second core column 92 and the third core column 93 are all provided with an upper winding 2 and a lower winding 3; an upper cross iron 94 is provided between the top of the first core column 91, the top of the second core column 92 and the top of the third core column 93; a lower cross iron 95 is provided between the bottom of the first core column 91, the bottom of the second core column 92 and the bottom of the third core column 93.

[0050] Specifically, through the above arrangement, this embodiment can respectively wind one layer of upper winding 2 and lower winding 3 outside the first core column 91, outside the second core column 92 and outside the third core column 93, thereby forming a three-phase transformer.

[0051] A method for manufacturing an improved foil-wound coil structure according to this embodiment includes the following steps:

[0052] S1, laminating the upper coil foil 21 and the upper interlayer insulating paper 22 together, and laminating the lower coil foil 31 and the lower interlayer insulating paper 32 together;

[0053] S2, simultaneously winding the upper coil foil 21 and the upper interlayer insulating paper 22 along the top of the core column 1 and winding the lower coil foil 31 and the lower interlayer insulating paper 32 along the bottom of the core column 1;

[0054] S3, connecting the end of the upper coil foil 21 and the beginning of the lower coil foil 31 in series.

[0055] Specifically, the manufacturing method for manufacturing an improved foil-wound coil structure described in this embodiment divides the total number of turns of the improved foil-wound coil structure into two parts, an upper and a lower part, for winding. The upper and lower parts are each wound half and then connected in series, so that the number of turns is reduced to half of the original number, thereby effectively improving production efficiency. At the same time, since the number of coil winding layers is halved, the total amount of upper interlayer insulating paper 22 and lower interlayer insulating paper 32 is also reduced to half of the original number, thereby reducing material costs.

[0056] In the manufacturing method for manufacturing an improved foil-wound coil structure described in this embodiment, the selection of the width of the upper coil foil strip 21 and the width of the lower coil foil strip 31 includes the following steps:

[0057] A1. Measure the height of the top surface of the lower coil foil 31 and the height of the top surface of the upper coil foil 21;

[0058] A2. After current is passed, measure the temperature rise of the upper winding 2 and the temperature rise of the lower winding 3;

[0059] A3. Calculate the unit heat load of the upper coil foil 21 and the unit heat load of the lower coil foil 31 according to the formula T=k1*(H / 1000)^0.2*q^0.8; where T is the temperature rise, k1 is the temperature rise coefficient, H is the height of the top surface of the coil foil, and q is the unit heat load;

[0060] A4. Convert the unit heat load of the upper coil foil 21 into the coil temperature rise value T1 and convert the unit heat load of the lower coil foil 31 into the coil temperature rise value T2. According to the principle of T1=T2, calculate the width of the upper coil foil 21 and the width of the lower coil foil 31.

[0061] In actual applications, in order to facilitate the purchase of foil, the width of the foil is usually rounded to 10 or 5, so the temperature rise T1 and T2 of the upper and lower coils will be slightly different.

[0062] Specifically, for easier understanding, an example is given below:

[0063] 1. Traditional products, whose winding is wound by a whole foil strip and interlayer insulation paper:

[0064] 1) The foil tape is 0.6mm thick * 400mm wide / 50 turns 60kg;

[0065] 2) The interlayer insulation paper uses 0.14mm thickness * 420mm width / 50 turns 6.5kg;

[0066] 3) Calculate the temperature rise: coil height H=0.4m, unit heat load q=0.11*10^4 W / m^2, coefficient k1=0.432, coil temperature rise To=0.432*0.4^0.2*(0.11*10^4)^0.8=97.5K.

[0067] 2. Products with patent number 2024103286983:

[0068] Since the coils are placed up and down, the foil thickness and width of the upper and lower coils are the same, and the thickness of the foil is twice that of the traditional product: 0.6*2=1.2mm, and the width is half of the traditional product: 400 / 2=200mm, keeping the current density of the winding unchanged, so:

[0069] 1) The foil tape is 1.2mm thick * 200mm wide / (upper 25 turns + lower 25 turns), about 60kg, and the total weight is basically unchanged. Here, the upper winding foil tape is 200mm wide and the lower winding foil tape is 200mm wide;

[0070] 2) The interlayer insulation paper is 0.14mm thick * 215mm wide (upper 25 turns + lower 25 turns) / 3.26kg. The upper interlayer insulation paper is 215mm wide and the lower interlayer insulation paper is 215mm wide. Compared with the traditional product of 6.5kg interlayer insulation paper, the amount is reduced by about half, saving material costs.

[0071] 3) Temperature rise calculation: when the foil is divided equally, the height of the top surface of the lower foil is H=200mm, the distance between the top surface of the lower foil and the bottom surface of the upper foil is D=20mm, and the height of the top surface of the upper coil is H=200+20+200=420mm. Since the current density of the winding and the placement of the air duct have not changed, the unit heat load q value is still 0.11*10^4W / m^2, the air duct has not changed, and the outer circumference of the coil has not changed. At this time,

[0072] Lower winding temperature rise Tlower = 0.432*0.2^0.2*(0.11*10^4)^0.8=85K,

[0073] Upper winding temperature rise Tup = 0.432*0.42^0.2*(0.11*10^4)^0.8 = 98.5K,

[0074] From the above, it can be seen that the product with patent number 2024103286983 does save insulation paper, but the temperature rise of the upper and lower coils differs by 13.5K.

[0075] 3. The product of this embodiment:

[0076] Similarly, since the coils are placed up and down, the total foil width is 400mm, the width of the upper coil foil 21 is 220, and the width of the lower coil foil 31 is 180. Then the height of the top surface of the lower coil foil 31 is H1=180mm, the distance between the top surface of the lower coil foil 31 and the bottom surface of the upper coil foil 21 is D1=20mm, and the height of the top surface of the upper coil foil 21 is H2=180+D20+220=420mm. The thickness of the upper coil foil 21 and the thickness of the lower coil foil 31 are selected to be twice that of the traditional product, 0.6*2=1.2mm; the width of the upper coil insulation paper is 235mm, and the width of the lower coil insulation paper is 195mm. At this time, since the total width of the foil and the total width of the interlayer insulation paper are the same as the product with patent number 2024103286983, the dosage is also the same:

[0077] 1) The sum of the upper and lower coil foil strips 31 is still 60 kg, and the total weight is basically unchanged. Here, the width of the upper coil foil strip 21 is 220 mm, and the width of the lower coil foil strip 31 is 180 mm;

[0078] 2) The sum of the insulation paper 32 between the upper and lower layers is still 3.26kg. Here, the width of the upper insulation paper 22 is 235mm, and the width of the lower insulation paper 32 is 195mm. Compared with the traditional product of 6.5kg insulation paper between layers, the amount of insulation paper used is reduced by about half.

[0079] 3) Temperature rise calculation: when the width of the lower coil foil 31 is 180, the airway does not change, and the outer circumference of the coil does not change. At this time, the current density increases and the unit heat load increases.

[0080] Unit heat load q = 0.11 / 180*200 = 0.1222*10^4 W / m^2,

[0081] Lower winding 3 temperature rise Tlower = 0.432*0.18^0.2*(0.1222*10^4)^0.8=90.3K;

[0082] When the width of the upper coil foil 21 is 220, the air passage does not change, and the outer circumference of the coil does not change. At this time, the current density decreases and the unit heat load decreases.

[0083] Unit heat load qup = 0.11 / 220*200 = 0.1*10^4 W / m^2,

[0084] The temperature rise of upper winding 2 is Tup = 0.432*0.42^0.2*(0.1*10^4)^0.8 = 91.2K.

[0085] From the above calculation, it can be seen that the maximum temperature rise of the present invention is reduced by about 98.5-91.2=7.3K compared with the product of Patent No. 2024103286983; the temperature rise is reduced by about 97.5-91.2=6.3K compared with the traditional product; from the above example, it can be seen that the present invention not only saves insulation paper, but also reduces the temperature rise of the hot spot of the coil.

[0086] It is not difficult to understand that the higher the coil is, the longer the internal air duct is, and the greater the obstruction to the airflow is. Therefore, the higher the coil is, the more uneven the temperature distribution is, resulting in a phenomenon in which the temperature at the upper part of the coil is high and the temperature at the lower part is low. After the coil is segmented, the present invention appropriately adjusts the foil width ratio of the upper and lower windings 3, and substitutes the height data that affects the temperature rise of the coil into the calculation, so that a better foil width combination of the upper and lower windings 3 can be obtained, such as Figure 5 As shown, the temperature rise of the hot spot of the coil is reduced without increasing the amount of foil used; in fact, the existence of the middle spacing D1 of the coil is more conducive to heat dissipation; in terms of cost, the cost of the insulating paper is halved after the number of winding turns is halved, and the amount of insulating paper is halved; in terms of working hours, only half the number of turns is needed, which is also reduced to about 50% of the previous time; in terms of size, since the number of insulating paper layers is halved, the pure thickness of the coil is smaller and the power density of the product is higher; the foil tape described in the present invention mainly refers to low-resistivity conductors such as copper foil and aluminum foil.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An improved foil coil structure, characterized in that: The invention comprises an iron core column (1); the iron core column (1) is wound with an upper winding (2) and a lower winding (3); the upper winding (2) is formed by winding an upper coil foil (21) and an upper interlayer insulating paper (22) which are bonded to each other along the top of the iron core column (1); the lower winding (3) is formed by winding a lower coil foil (31) and a lower interlayer insulating paper (32) which are bonded to each other along the bottom of the iron core column (1); The upper coil foil strip (21) and the lower coil foil strip (31) are connected in series, and the sum of the number of turns of the upper coil foil strip (21) and the number of turns of the lower coil foil strip (31) after the series connection is the total number of turns of the improved foil-wound coil structure; The thickness of the upper coil foil (21) is the same as that of the lower coil foil (31); and the width of the upper coil foil (21) is greater than that of the lower coil foil (31).

2. The improved foil coil structure according to claim 1, characterized in that: A ventilation gap (4) is provided between the upper winding (2) and the lower winding (3).

3. The improved foil-wound coil structure according to claim 1, characterized in that: The upper winding (2) is provided with an upper air duct (51); and the lower winding (3) is provided with a lower air duct (52).

4. The improved foil coil structure according to claim 1, characterized in that: The width of the upper interlayer insulating paper (22) is greater than the width of the upper coil foil (21); and the width of the lower interlayer insulating paper (32) is greater than the width of the lower coil foil (31).

5. The improved foil-wound coil structure according to claim 1, characterized in that: An upper inlet wire row (61) is provided on the inner side of the front end of the top of the core column (1); a lower inlet wire row (71) is provided on the inner side of the front end of the bottom of the core column (1); An upper outgoing wire row (62) is provided on the outer side of the front end of the top of the core column (1); the upper outgoing wire row (62) passes through the lower winding (3) and extends to the bottom of the core column (1); a lower outgoing wire row (72) is provided on the outer side of the front end of the bottom of the core column (1); the lower outgoing wire row (72) passes through the upper winding (2) and extends to the top of the core column (1); The upper outlet row (62) is connected in series with the lower inlet row (71); The upper coil foil strip (21) is arranged between the upper incoming wire row (61) and the upper outgoing wire row (62), and is respectively welded to the upper incoming wire row (61) and the upper outgoing wire row (62) before being led out; the lower coil foil strip (31) is arranged between the lower incoming wire row (71) and the lower outgoing wire row (72), and is respectively welded to the lower incoming wire row (71) and the lower outgoing wire row (72) before being led out.

6. The improved foil-wound coil structure according to claim 5, characterized in that: The bottom of the upper outlet row (62) and the top of the lower outlet row (72) are both covered with insulating tape (81).

7. The improved foil-wound coil structure according to claim 5, characterized in that: The bottom of the upper outlet row (62) and the top of the lower outlet row (72) are both covered with insulating paper pads (82).

8. The improved foil coil structure according to claim 1, characterized in that: The iron core column (1) comprises a first core column (91), a second core column (92) and a third core column (93); the first core column (91), the second core column (92) and the third core column (93) are all provided with an upper winding (2) and a lower winding (3); An upper cross iron (94) is provided between the top of the first core column (91), the top of the second core column (92) and the top of the third core column (93); and a lower cross iron (95) is provided between the bottom of the first core column (91), the bottom of the second core column (92) and the bottom of the third core column (93).

9. A method for manufacturing the improved foil-wound coil structure according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, laminating the upper coil foil (21) and the upper interlayer insulating paper (22) together, and laminating the lower coil foil (31) and the lower interlayer insulating paper (32) together; S2, simultaneously winding the upper coil foil (21) and the upper interlayer insulating paper (22) along the top of the iron core column (1), and winding the lower coil foil (31) and the lower interlayer insulating paper (32) along the bottom of the iron core column (1); S3, connecting the end of the upper coil foil (21) and the beginning of the lower coil foil (31) in series.

10. A manufacturing method according to claim 9, characterized in that: The selection of the width of the upper coil foil (21) and the width of the lower coil foil (31) comprises the following steps: A1. measuring the height of the top surface of the lower coil foil (31) and the height of the top surface of the upper coil foil (21); A2. After current is passed, the temperature rise of the upper winding (2) and the temperature rise of the lower winding (3) are measured; A3. Calculate the unit heat load of the upper coil foil (21) and the unit heat load of the lower coil foil (31) according to the formula T=k1*(H / 1000)^0.2*q^0.8; wherein T is the temperature rise, k1 is the temperature rise coefficient, H is the height of the top surface of the coil foil, and q is the unit heat load; A4. Convert the unit heat load of the upper coil foil (21) into the coil temperature rise value T1 and convert the unit heat load of the lower coil foil (31) into the coil temperature rise value T2. According to the principle of T1=T2, calculate the width of the upper coil foil (21) and the width of the lower coil foil (31).

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