Mainboard bonding pad layout structure and method for preventing short circuit

Abstract

The invention provides a mainboard bonding pad layout structure and method for preventing short circuit, and the structure comprises a mainboard which comprises a body, and a positive bonding pad and a negative bonding pad which are disposed on the body in a staggered manner; the battery also comprises a battery cell, the battery cell is suspended above the main board, when the battery cell is observed in the height direction of the main board, the positive electrode bonding pad is located on one side of the battery cell, the negative electrode bonding pad is located on the other side, away from the positive electrode bonding pad, of the battery cell, and the distance between two welding points correspondingly generated by welding of the two bonding pads is larger than 0; the battery cell comprises a positive electrode wire and a negative electrode wire, the positive electrode wire and the negative electrode wire have a length difference, the positive electrode wire is welded with the positive electrode bonding pad, and the negative electrode wire is welded with the negative electrode bonding pad. Through the structure, short circuit is prevented.

Description

Technical Field

[0001] The present application relates to the field of small electronic processing, and in particular to a mainboard pad layout structure and method for preventing short circuits. Background Art

[0002] With the development of miniaturized electronic devices, users pay more and more attention to the performance, safety and reliability of miniaturized batteries. At present, most batteries on the market use built-in protection boards or protection circuits. The protection board or protection circuit can automatically disconnect the circuit when the battery short-circuits to protect the battery from damage. In small electronic devices, batteries without protection circuits are called batteries.

[0003] Miniaturized electronic devices often cannot use protection boards due to space constraints. When a battery cell without a protection circuit short-circuits, it is often accompanied by violent chemical reactions and physical changes, such as burning, melting, or structural damage of internal materials. Once the phenomenon in the short-circuit process occurs, it will cause permanent damage to the battery cell, making it impossible to restore it to the state before the short-circuit.

[0004] In the existing small electronic processing process, short circuits are prone to occur in the following situations: the positive and negative wires of the battery core are prone to touching each other. Also, the tin flow of the positive and negative pads is prone to flow unevenly, resulting in the positive and negative pads being connected. Therefore, a mainboard pad layout structure and method for preventing short circuits is needed. Summary of the invention

[0005] In view of this, it is necessary to provide a mainboard pad layout structure for preventing short circuits to solve the above problems.

[0006] The embodiment of the present application provides a mainboard pad layout structure for preventing short circuit, including:

[0007] A main board, comprising a main body, a positive electrode pad and a negative electrode pad staggeredly disposed on the main body;

[0008] The battery cell is suspended above the main board. When viewed along the height direction of the main board, the positive electrode pad is located on one side of the battery cell, the negative electrode pad is located on the other side of the battery cell away from the positive electrode pad, and the distance between two corresponding welding points generated by welding the two pads is greater than 0;

[0009] The battery core comprises: a positive electrode wire and a negative electrode wire, the positive electrode wire and the negative electrode wire have a length difference, the positive electrode wire is welded to the positive electrode pad, and the negative electrode wire is welded to the negative electrode pad.

[0010] In at least one embodiment of the present application, the length of the positive electrode wire is recorded as D1, and the length of the negative electrode wire is recorded as D2, satisfying the relationship:

[0011] D1≠D2;

[0012] The positive electrode wire and the negative electrode wire are arranged on the same side of the battery cell, and this side is set as the connection side.

[0013] In at least one embodiment of the present application, when D1>D2, the negative electrode pad is close to the connection side, and the positive electrode pad is far away from the connection;

[0014] When D1<D2, the positive electrode pad is close to the connection side, and the negative electrode pad is far away from the connection.

[0015] In at least one embodiment of the present application, the positive electrode wire and the negative electrode wire both include:

[0016] An insulating portion, one end of which is connected to the inside of the battery core, and the insulating portion includes a bending structure generated by the wire during the routing process;

[0017] The terminal is connected to an end of the insulating portion away from the battery core and is welded to the welding pad, wherein when D1≠D2, the two terminals do not touch each other.

[0018] In at least one embodiment of the present application, the positive electrode pad is a first V-shaped tin guide groove, the negative electrode pad is a second V-shaped tin guide groove, the V-shaped tin guide groove is inclined along the bending direction of the bending structure, and the wire is placed in the V-shaped tin guide groove.

[0019] In at least one embodiment of the present application, when viewed along the width direction of the mainboard, the first V-shaped tin-leading groove and the second V-shaped tin-leading groove both include:

[0020] The tin-leading surface is connected to the main board obliquely along the bending direction, and the tin-leading surface is close to the connection side, and the wire is attached to and placed in the V-shaped tin-leading groove along the inclination angle of the tin-leading surface;

[0021] The tin-blocking surface has one end vertically connected to the mainboard and the other end connected to the tin-leading surface and away from the connecting side, and the tin-leading surface and the tin-blocking surface are arranged opposite to each other.

[0022] In at least one embodiment of the present application, the first V-shaped tin-inducing groove includes a first tin-inducing surface and a first tin-blocking surface, the second V-shaped tin-inducing groove includes a second tin-inducing surface and a second tin-blocking surface, and the first tin-blocking surface is located between the first tin-inducing surface and the second tin-blocking surface.

[0023] In at least one embodiment of the present application, the inclination angle of the tin-leading surface is 30° to 45°.

[0024] In at least one embodiment of the present application, the width of the V-shaped tin-leading groove is between 1.5 times and 2 times the diameter of the end head;

[0025] The depth of the V-shaped tin-leading groove ranges from 0.5 times to 1 times the diameter of the end head.

[0026] In at least one embodiment of the present application, the method is applied to any of the above-mentioned mainboard pad layout structures for preventing short circuits, and comprises the steps of:

[0027] Design and layout the mainboard welding position so that the positive electrode welding pad and the negative electrode welding pad are staggered and arranged on the main body;

[0028] Designing the lengths of the positive electrode wire and the negative electrode wire so that there is a length difference between the positive electrode wire and the negative electrode wire;

[0029] The wire is bent and routed according to the direction of the corresponding tinning surface, so that the wire fits the tinning surface;

[0030] Welding the wire and the pad, with the tin flowing into the pad along the inclined tin-leading surface;

[0031] After the tin flow solidifies, welding is completed.

[0032] The beneficial effects of the mainboard pad layout structure and method for preventing short circuit provided above are:

[0033] By designing the positive and negative wires to be of unequal length, the two ends cannot touch each other during the processing or welding process.

[0034] At the same time, the positive and negative electrode pads are staggered on the main body so that the positions of the positive electrode pad and the negative electrode pad on the main board are staggered, thereby avoiding short circuits between the two welding points due to uneven solder flow or accidental contact with the positive and negative electrode wires due to the small distance between the positive electrode pad and the negative electrode pad during welding.

[0035] In addition, by setting the soldering pad as a V-shaped tin-leading groove, the tin flow can flow into the V-shaped tin-leading groove through the inclined tin-leading surface, and the wire is placed in the V-shaped tin-leading groove. After the tin flow solidifies, the welding of the wire and the tin-leading groove is completed; at the same time, when the tin flow is too large and overflows the V-shaped tin-leading groove, gravity analysis of the tin-blocking surface vertically connected to the mainboard and the tin-leading surface obliquely connected to the mainboard will cause the tin flow to overflow from one end of the inclined surface, while the first tin-leading surface is located at an end away from the second tin-leading surface, thereby preventing the tin flow from connecting the two soldering pads. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A three-dimensional diagram of the mainboard pad layout structure for preventing short circuits described in this application;

[0037] Figure 2 This is a schematic diagram of the mainboard observed along the height direction of the present application, and is also a top view of the mainboard pad layout structure;

[0038] Figure 3 for Figure 2 Sectional view of AA in the middle;

[0039] Figure 4 for Figure 3 A partial enlarged view of the middle BB;

[0040] Figure 5 for Figure 3 The schematic diagram of the BB terminal not being placed in the pad;

[0041] Figure 6 This is a schematic diagram of the structure of two pads on the main board;

[0042] Figure 7 A flow chart of a mainboard pad layout method for preventing short circuits described in this application;

[0043] Main component symbols

[0044] 100. A mainboard pad layout structure for preventing short circuits; 10. mainboard; 11. main body; 12. positive pad; 13. negative pad; 20. battery cell; 21. positive wire; 22. negative wire; 30. connection side; 211. insulating portion; 2111. bending structure; 212. terminal; 121. tin-leading surface; 1211. first tin-leading surface; 1212. second tin-leading surface; 122. tin-blocking surface; 1221. first tin-blocking surface; 1222. second tin-blocking surface; A. tilt angle; F1. height direction of the mainboard; F2. width direction of the mainboard; 200. A mainboard pad layout method for preventing short circuits. DETAILED DESCRIPTION

[0045] The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0046] It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "located on" another component, it may be directly located on the other component or there may be a central component at the same time. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "back", and similar expressions used herein are for illustrative purposes only.

[0047] Some embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0048] See also Figure 1-Figure 7 The embodiment of the present application provides a mainboard 10 pad layout structure 100 for preventing short circuit, comprising: a mainboard 10 and a battery cell 20. The mainboard 10 comprises a body 11, a positive electrode pad 12 and a negative electrode pad 13 staggeredly arranged on the body;

[0049] The battery cell 10 is suspended above the main board 10. When viewed along the height direction F1 of the main board, the positive electrode pad 12 is located on one side of the battery cell 20, and the negative electrode pad 13 is located on the other side of the battery cell 20 away from the positive electrode pad 12. The distance between the two welding points corresponding to the pad welding is greater than 0. The battery cell 20 includes a positive electrode wire 21 and a negative electrode wire 22. The positive electrode wire 21 and the negative electrode wire 22 have a length difference. The positive electrode wire 21 is welded to the positive electrode pad 12, and the negative electrode wire 22 is welded to the negative electrode pad 13.

[0050] Specifically, the battery cell 20 and the battery without a protection circuit are now welded to the pad of the mainboard 10, and the welding between the two is performed from top to bottom through the positive wire 21 and the negative wire 22 connected to the inside of the battery cell 20 and the corresponding positive pad 12 and negative pad 13.

[0051] The positive electrode wire 21 and the negative electrode wire 22 are respectively led out from the internal electrodes of the battery core 20 and extend from top to bottom to the corresponding pad positions on the main board 10. This ensures that the wires can be accurately connected to the designated pads during welding.

[0052] The battery cell 20 is suspended above the mainboard 10 to avoid the battery cell 20 occupying the layout space of the mainboard 10 when the layout space of the mainboard 10 is small. At the same time, the layout on the mainboard 10 is clear, and the wire can be more accurately positioned on the corresponding pad to ensure the welding quality and the reliability of the electrical connection. It also ensures that the wire has better spatial operability during the welding process. At the same time, the battery cell 20 is suspended above the mainboard 10 to reduce the area of ​​direct contact between the battery cell 20 and the mainboard 10, and reduce the influence of heat conduction during welding. Because the heat generated during welding is mainly concentrated on the wire and the pad, the suspended battery cell 20 greatly reduces the influence of heat and protects the stability and safety of the battery cell 20. In addition, the battery cell 20 is suspended above the mainboard 10 to form a certain height difference between the welding point of the wire and the mainboard 10, and the welding angle between the wire and the pad is determined by controlling the bending direction of the wire, which helps to control the flow path of the solder. The mainboard 10 is designed as an inclined V-shaped tin lead groove design, so that the flow direction of the solder is more controlled, avoiding the short circuit problem that may be caused by solder overflow.

[0053] The positions of the positive electrode pad 12 and the negative electrode pad 13 staggered on the main body 11 on the plane of the main board 10 are no longer linearly symmetrical, but are scattered on both sides of the battery cell 20. For example, the positive electrode pad 12 may be located on the right side of the battery cell 20, while the negative electrode pad 13 is located on the left side of the battery cell 20. It is also possible that the positive electrode pad 12 is located on the upper right side of the battery cell 20, while the negative electrode pad 13 is located on the lower left side of the battery cell 20. The positive electrode pad 12 and the negative electrode pad 13 are staggered in the position of the positive electrode pad 12 arranged on the main body 11, as long as the distance between the welding points generated by welding the positive electrode pad 12 and the positive electrode wire 21 and the welding points generated by welding the negative electrode pad 13 and the negative electrode wire 22 on the main body 11 is too large, the distance between the two welding points is still greater than 0. The horizontal distance (the length of the main board 10 and the width of the main board 10) with the negative electrode pad 13 on the main body 11 is increased. The increased distance between the positive electrode pad 12 and the negative electrode pad 13 creates a physical barrier between the welding points, which not only makes it more difficult for them to contact each other, but also reduces the risk of short circuits caused by wire deviation or uneven solder flow.

[0054] Solder usually flows during the welding process. If the pads are too close, the solder may accidentally flow to the adjacent pads, resulting in a poor connection between the positive and negative electrodes and causing a short circuit. By staggering the positive and negative electrode pads 13, the flow path of the solder can be effectively controlled so that it flows along a predetermined direction and range.

[0055] Due to the staggered position of the pads, during welding, the flow direction of the solder will be affected by the pad position and the welding angle. The distance and layout between the positive and negative electrode pads 13 set the path for the solder flow. The distance and layout between the positive and negative electrode pads 13 make it difficult for the tin flow to cross the gap between the pads or connect two welding points through irregular solder flow. The solder usually flows downward along the inclined surface of the pad and eventually solidifies at a designated position to form a welding point. By designing the inclination angle A and relative position of the pad, it is ensured that the flow direction of the solder can be precisely controlled, reducing the possibility of abnormal solder joints or short circuits during the welding process.

[0056] The positive wire 21 and the negative wire 22 of the battery cell 20 have different lengths, where the length of the positive wire 21 is recorded as D1, and the length of the negative wire 22 is recorded as D2. The length difference between D1 and D2 (i.e., D1≠D2) ensures that the ends 212 of the two wires always maintain a certain distance during processing and welding, and cannot touch each other. This design greatly reduces the possibility of short circuit caused by the wire ends 212 touching each other.

[0057] In a specific embodiment, the length of the positive electrode wire 21 is recorded as D1, and the length of the negative electrode wire 22 is recorded as D2, which satisfies the relationship:

[0058] D1≠D2;

[0059] The positive electrode wire 21 and the negative electrode wire 22 are arranged on the same side of the battery cell 20 , and this side is set as the connection side 30 .

[0060] Specifically, by making the positive electrode wire 21 and the negative electrode wire 22 of different lengths, the ends 212 of the two wires can be kept at a certain distance during the welding process to prevent them from contacting each other during the welding process. Due to the difference in length, the positive and negative electrode wires 22 will form different paths during welding, thereby reducing the possibility of them contacting each other or causing a short circuit.

[0061] In a specific embodiment, when D1>D2, the negative electrode pad 13 is close to the connection side 30, and the positive electrode pad 12 is far away from the connection; when D1<D2, the positive electrode pad 12 is close to the connection side 30, and the negative electrode pad 13 is far away from the connection.

[0062] Specifically, the length difference between the positive wire 21 and the negative wire 22 also determines the different paths of the positive and negative wires 22 during welding, avoiding them from being too close at the welding point, and further preventing accidental connection when the solder flows.

[0063] At the same time, the influence of the wire length is taken into account to ensure that the wire can be connected to the pad in the optimal path during welding, avoiding unnecessary crossing or overlapping of the wire during welding. In addition, such an arrangement also effectively increases the physical distance between the positive and negative electrode pads 13, so that additional physical isolation is formed between the welding points, further preventing the occurrence of short circuits.

[0064] In a specific embodiment, the positive electrode wire 21 and the negative electrode wire 22 both include: an insulating portion 211 and a terminal 212. One end of the insulating portion 211 is connected to the inside of the battery cell 20, and the insulating portion 211 includes a bending structure 2111 generated during the wiring of the wire. The terminal 212 is connected to one end of the insulating portion 211 away from the battery cell 20 and is welded to the pad, wherein when D1≠D2, the two terminals 212 do not touch each other.

[0065] Specifically, the insulating portion 211 is located on the outer layer of the wire and is usually made of an electrical insulating material. One end is connected to the inside of the battery core 20 and the other end is connected to the end 212 of the wire. The wire forms a bent structure 2111 during the routing process.

[0066] The main function of the insulating portion 211 is to prevent accidental contact between the wires and between the wires and other electrical components to avoid short circuits. The bending structure 2111 can provide additional flexibility during the routing process, adapt to the layout requirements of the motherboard 10, and ensure the fixation and stability of the wires.

[0067] The terminal 212 is the end portion of the wire, and is used to directly solder to the pad on the mainboard 10 to complete the electrical connection. The terminal 212 is the key point for connecting the wire to the pad, and directly affects the welding quality and the reliability of the electrical connection. By ensuring the precise connection between the terminal 212 and the pad, the structure and length setting of the terminal 212 can effectively avoid short circuits caused by wire movement or improper solder flow.

[0068] In a specific embodiment, the positive electrode pad 12 is a first V-shaped tin-leading groove, and the negative electrode pad 13 is a second V-shaped tin-leading groove. The V-shaped tin-leading groove is inclined along the bending direction of the bending structure 2111, and the wire is placed in the V-shaped tin-leading groove.

[0069] Specifically, the purpose of setting the solder pad into a V-shape is to guide the solder into the groove to ensure that the flow of the solder during the soldering process is concentrated and controllable.

[0070] The V-shaped soldering groove is aligned with the bending direction and tilted according to the bending direction of the wire, which enhances the accuracy of the soldering process, ensuring that the solder flows along the predetermined path and forms a precise contact point at the pad.

[0071] The V-shaped solder guide groove guides the flow of solder to prevent solder overflow, and reduces the possibility of solder bridging between the positive and negative electrode pads 13 compared to ordinary pads, thereby avoiding potential short circuit risks.

[0072] By making the V-shaped soldering groove consistent with the bending direction of the wire, the stress on the wire and the pad is reduced, ensuring smooth solder flow, thereby ensuring the reliability of the electrical connection.

[0073] The wire is held in the V-shaped soldering groove during the soldering process, reducing the risk of displacement, thus forming a strong and reliable connection.

[0074] In a specific embodiment, observed along the width direction of the main board 10, the first V-shaped tin-leading groove and the first V-shaped tin-leading groove both include a tin-leading surface 121 and a tin-blocking surface 122. The tin-leading surface 121 is obliquely connected to the main board 10 along the bending direction, and the tin-leading surface 121 is close to the connection side 30, and the wire is attached and placed in the V-shaped tin-leading groove along the inclination angle A of the tin-leading surface 121. One end of the tin-blocking surface 122 is vertically connected to the main board 10, and the other end of the tin-blocking surface 122 is connected to the tin-leading surface 121. The tin-blocking surface 122 is away from the connection side 30, and the tin-leading surface 121 and the tin-blocking surface 122 are arranged opposite to each other.

[0075] Specifically, the V-shaped soldering groove controls the direction of solder flow by designing the tilt angle A of the soldering surface 121 to prevent the solder from accidentally flowing to the adjacent pad due to gravity or surface tension. The depth and width of the V-shaped soldering groove are designed to adapt to the bending direction of the wire, so that the wire can be stably placed in the groove, reducing the possibility of wire displacement during welding.

[0076] The tin-leading surface 121 is a portion that is connected to the main board 10 obliquely along the bending direction of the wire. It is located on the inner side of the V-shaped tin-leading groove, close to the connection side 30 of the battery cell 20. When welding, the wire is attached and placed in the groove along the inclination angle A of the tin-leading surface 121. The inclined design of the tin-leading surface 121 not only guides the flow of solder, but also ensures that the solder can reach the specified position of the pad along a predetermined direction, thereby forming a stable welding point. The inclined tin-leading surface 121 allows the solder to flow along a fixed path, avoiding short circuits caused by uncontrolled solder flow during welding.

[0077] The tin blocking surface 122 is vertically connected to the main board 10 and forms a groove structure with the tin lead surface 121 to limit the flow range of the solder, but it only provides a temporary physical barrier. When the solder flow is too large, the tin blocking surface 122 cannot actually completely prevent the solder from overflowing the groove, but guides it to flow out in a controlled manner.

[0078] When the solder flow is too large, the role of the solder blocking surface 122 is more to guide the overflowing solder to a safer area rather than completely preventing it from overflowing.

[0079] When the tin flow is too large and exceeds the capacity of the tin-leading groove, the tin flow will continue to flow out of the groove along the inclined angle A of the tin-leading surface 121, rather than flowing out along the tin-blocking surface 122. The reason is that the tin-blocking surface 122 is vertically connected to the motherboard 10 and does not have an inclined angle A. Therefore, the tin-blocking surface 122 does not guide the tin flow, but forms a physical barrier. When the tin flow faces the tin-blocking surface 122, it cannot flow smoothly due to the lack of guidance of the inclined angle A, so it will preferentially continue to flow along the tin-leading surface 121.

[0080] The inclination angle A of the tin-leading surface 121 plays a guiding role, making the flow path of the tin flow in the slot more clear and controllable. When the tin flow is too large, the tin-leading surface 121 flows out of the slot along the tin-leading surface 121. This process is because the tin-leading surface 121 provides a natural flow direction for the tin flow. In contrast, the tin-blocking surface 122 is more like a vertical barrier to prevent the tin flow from overflowing in the opposite direction.

[0081] In a specific embodiment, observed along the width direction F2 of the main board, the first V-shaped tin-leading groove includes a first tin-leading surface 1211 and a first tin-blocking surface 1221, the second V-shaped tin-leading groove includes a second tin-leading surface 12121 and a second tin-blocking surface 1222, the first tin-leading surface 1211 is away from one end of the second tin-leading surface 12121, and the first tin-blocking surface 1221 is located between the first tin-leading surface 1211 and the second tin-leading surface 12121.

[0082] Specifically, the first tin blocking surface 1221 is located between the first tin introducing surface 1211 and the second tin introducing surface 12121 , and plays an isolating role. When the tin flow in the two V-shaped tin introducing grooves is too large, the flow paths of the two tin flows are isolated by the first tin blocking surface 1221 .

[0083] Make sure the solder in the two V-grooves will not mix with each other. This design ensures that the flow path of the solder between the two pads is independent and controllable.

[0084] In a specific embodiment, the inclination angle A of the tin-leading surface 121 is 30° to 45°. The inclination angle A is the angle formed between the tin-leading surface 121 and the welding surface of the body 11 .

[0085] Specifically, using V-shaped tin-leading bath samples of the same specification, the only variable is the inclination angle A of the tin-leading surface 121. Multiple samples with different inclination angles A are selected, including 20°, 25°, 30°, 35°, 40°, 45°, 50°, etc.

[0086] The solder is melted at a constant speed and temperature, and then introduced into each V-shaped soldering trough with different inclination angles A. The flow path of the solder in the trough, the welding time, the formation of the solder joint, and whether there is overflow or short circuit are recorded. Finally, the quality of the solder joint is evaluated, including the firmness of the solder joint, the uniformity of the solder distribution, and the electrical performance test after the welding is completed.

[0087] The data obtained are as follows:

[0088]

[0089] With the above experimental data records, it can be concluded that:

[0090] When the tilt angle A is between 30° and 45°, the solder flow path is the most stable, and it can flow evenly to the pad and form a solid solder joint. When the angle is lower than 30° or higher than 45°, the fluidity of the solder is affected, making it difficult to control the solder and the flow path unstable.

[0091] The angles of 20° and 25° flow faster, causing the solder to easily overflow the groove. In the range of 30° to 45°, the chance of solder overflow is greatly reduced, especially at 35° and 45°, where there is almost no overflow. At an angle of 50°, due to the slow flow, the solder does not overflow in large quantities, but the quality of the solder joint is affected.

[0092] When the tilt angle A is between 30° and 45°, the tensile test results of the weld point show high mechanical strength and the best quality of the weld point. When the angle is lower than 30° or higher than 45°, the quality of the weld point decreases.

[0093] In the range of 30° to 45°, the electrical performance of the solder joint is the best, with no short circuit. Solder joints at other angles may have short circuits or unstable electrical performance.

[0094] Therefore, a tilt angle A of 30° to 45° provides the best balance between solder flow, solder joint quality and electrical performance.

[0095] In a specific embodiment, the width of the V-shaped tin-leading groove ranges from 1.5 times to 2 times the diameter of the end head 212 , and the depth of the V-shaped tin-leading groove ranges from 0.5 times to 1 times the diameter of the end head 212 .

[0096] Specifically, in the width experimental data, V-shaped tin-leading bath samples of the same specification are used, and the only variable is the width of the V-shaped tin-leading bath sample. The width is 1.2 times, 1.5 times, 1.75 times, 2 times, and 2.5 times the diameter of the end 212;

[0097] At the same solder flow rate and temperature, the solder is introduced into a V-shaped soldering bath with different parameter combinations. The flow of the solder, the quality of the solder joints, the overflow during the soldering process, and the mechanical and electrical properties after soldering are recorded.

[0098]

[0099]

[0100] From the above data, it can be seen that when the width of the V-shaped soldering groove is between 1.5 and 2 times the diameter of the end, the solder fluidity is most stable, the solder joint quality is optimal, the overflow is minimal, and the mechanical strength and electrical properties after welding are also in the best state. When the width is less than 1.5 times or more than 2 times, the solder fluidity deteriorates, the overflow increases, the solder joint quality decreases, and the welding strength and electrical properties deteriorate.

[0101] In the depth test data, the V-shaped tin lead bath samples of the same specifications are used, and the only variable is the depth of the V-shaped tin lead bath samples. Depth range: Depth range: 0.3 times, 0.5 times, 0.75 times, 1 times, 1.2 times the end diameter;

[0102]

[0103] From the above experimental data, it can be seen that when the depth of the V-shaped soldering groove is between 0.5 and 1 times the diameter of the end, the solder controllability is the best, the solder joint quality is the highest, and the overflow is the least, and the mechanical strength and electrical properties after welding are also in the best state. When the depth is less than 0.5 times or more than 1 times, the solder fluidity and solder joint quality decrease, resulting in increased overflow and affecting the welding strength and electrical properties.

[0104] From the above experimental data, it can be seen that when the depth of the V-shaped soldering groove is between 0.5 and 1 times the diameter of the end 212, the solder controllability is optimal, the solder joint quality is the highest, and the overflow is the least, and the mechanical strength and electrical performance after welding are also in the best state. When the depth is less than 0.5 times or greater than 1 times, the solder fluidity and solder joint quality decrease, resulting in increased overflow and affecting the welding strength and electrical performance.

[0105] A method for layout of pads of a mainboard 10 for preventing short circuits is applied to any of the above-mentioned pad layout structures 100 of mainboard 10 for preventing short circuits, and the method comprises the steps of:

[0106] S10, designing and laying out the welding position of the main board 10, so that the positive electrode pad 12 and the negative electrode pad 13 are staggered and arranged on the main body 11;

[0107] S20, designing the lengths of the positive electrode wire 21 and the negative electrode wire 22 so that there is a length difference between the positive electrode wire 21 and the negative electrode wire 22;

[0108] S30, the wire is bent and routed according to the direction of the corresponding tin-leading surface 121, so that the wire is attached to the tin-leading surface 121;

[0109] S40, welding the wire and the pad, and the tin flow flows into the pad along the inclined tin-leading surface 121;

[0110] S50, after the tin flow solidifies, welding is completed.

[0111] The present invention provides a method for layout of solder pads of a mainboard 10 for preventing short circuits, which is based on the above-mentioned structure 100 for layout of solder pads of a mainboard 10 for preventing short circuits. Therefore, the technical effects possessed by the above-mentioned structure 100 for layout of solder pads of a mainboard 10 for preventing short circuits are also possessed by the structure 100 for layout of solder pads of a mainboard 10 for preventing short circuits, which will not be repeated here.

[0112] The above is only an implementation method of the present application. It should be pointed out that a person skilled in the art can make improvements without departing from the inventive concept of the present application, but these improvements are within the scope of protection of the present application.

Claims

1. A mainboard pad layout structure for preventing short circuits, characterized in that: include: A main board, comprising a main body, a positive electrode pad and a negative electrode pad staggeredly disposed on the main body; The battery cell is suspended above the main board. When viewed along the height direction of the main board, the positive electrode pad is located on one side of the battery cell, the negative electrode pad is located on the other side of the battery cell away from the positive electrode pad, and the distance between two corresponding welding points generated by welding the two pads is greater than 0; The battery core comprises: a positive electrode wire and a negative electrode wire, the positive electrode wire and the negative electrode wire have a length difference, the positive electrode wire is welded to the positive electrode pad, and the negative electrode wire is welded to the negative electrode pad.

2. The mainboard pad layout structure for preventing short circuit according to claim 1, characterized in that: The length of the positive electrode wire is recorded as D1, and the length of the negative electrode wire is recorded as D2, which satisfies the relationship: D1≠D2; The positive electrode wire and the negative electrode wire are arranged on the same side of the battery cell, and this side is set as the connection side.

3. The mainboard pad layout structure for preventing short circuit according to claim 2, characterized in that: When D1>D2, the negative electrode pad is close to the connection side, and the positive electrode pad is far away from the connection; When D1<D2, the positive electrode pad is close to the connection side, and the negative electrode pad is far away from the connection.

4. The mainboard pad layout structure for preventing short circuit according to claim 2, characterized in that: The positive lead and the negative lead both include: An insulating portion, one end of which is connected to the inside of the battery core, and the insulating portion includes a bending structure generated by the wire during the routing process; The terminal is connected to an end of the insulating portion away from the battery core and is welded to the welding pad, wherein when D1≠D2, the two terminals do not touch each other.

5. The mainboard pad layout structure for preventing short circuit according to claim 4, characterized in that: The positive electrode pad is a first V-shaped tin-leading groove, and the negative electrode pad is a second V-shaped tin-leading groove. The V-shaped tin-leading groove is inclined along the bending direction of the bending structure, and the wire is placed in the V-shaped tin-leading groove.

6. The mainboard pad layout structure for preventing short circuit according to claim 5, characterized in that: Observing along the width direction of the mainboard, the first V-shaped tin-leading groove and the second V-shaped tin-leading groove both include: The tin-leading surface is connected to the main board obliquely along the bending direction, and the tin-leading surface is close to the connection side, and the wire is attached to and placed in the V-shaped tin-leading groove along the inclination angle of the tin-leading surface; The tin-blocking surface has one end vertically connected to the mainboard and the other end connected to the tin-leading surface and away from the connecting side, and the tin-leading surface and the tin-blocking surface are arranged opposite to each other.

7. The mainboard pad layout structure for preventing short circuit according to claim 5, characterized in that: The first V-shaped tin-inducing groove includes a first tin-inducing surface and a first tin-blocking surface, and the second V-shaped tin-inducing groove includes a second tin-inducing surface and a second tin-blocking surface, wherein the first tin-blocking surface is located between the first tin-inducing surface and the second tin-inducing surface.

8. The mainboard pad layout structure for preventing short circuit according to claim 6, characterized in that: The inclination angle of the tin-leading surface is 30° to 45°.

9. The mainboard pad layout structure for preventing short circuit according to claim 4, characterized in that: The width of the V-shaped tin-leading groove is between 1.5 and 2 times the diameter of the end head; The depth of the V-shaped tin-leading groove ranges from 0.5 times to 1 times the diameter of the end head.

10. A mainboard pad layout method for preventing short circuits, characterized in that: Applied to the mainboard pad layout structure for preventing short circuits as described in any one of claims 1 to 9 above, the method comprises the steps of: Design and layout the mainboard welding position so that the positive electrode welding pad and the negative electrode welding pad are staggered and arranged on the main body; Designing the lengths of the positive electrode wire and the negative electrode wire so that there is a length difference between the positive electrode wire and the negative electrode wire; The wire is bent and routed according to the direction of the corresponding tinning surface, so that the wire fits the tinning surface; Welding the wire and the pad, with the tin flowing into the pad along the inclined tin-leading surface; After the tin flow solidifies, welding is completed.

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