Temperature and pressure sensor and welding method and welding jig thereof

Abstract

The invention provides a temperature and pressure sensor and a welding method and a welding jig thereof. The welding method of the temperature and pressure sensor comprises the steps that a plurality of welding assemblies are fixed to a base of a welding jig based on the welding jig, each welding assembly comprises a thermistor and a connecting piece which are oppositely arranged, and first pins of the thermistors and second pins of the connecting pieces are in lap joint in a one-to-one correspondence mode; molten solder balls are applied to the lap joint area of the first pin and the second pin in each welding assembly to form soldering tin, so that the first part of soldering tin makes contact with the bottom face of the second pin through the through hole, the second part of soldering tin is located in the through hole, the third part of soldering tin is located on the second pin, and an integrated welding layer is formed after solidification. Compared with manual fixing, the precision is higher, the fixing stability can be improved, the production efficiency can be improved, the cost is low, and the connection stability between the first pin and the second pin can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a temperature and pressure sensor and a welding method and welding jig thereof. BACKGROUND

[0002] In recent years, temperature and pressure sensors are widely used in the field of new energy vehicles, such as battery pack systems, thermal management circuits, etc., and are intelligent sensing terminal core components. Generally, the temperature and pressure sensor is integrated with a thermal resistor and a pressure sensor through a connecting piece, and the connecting piece and the thermal resistor need to be welded first in the production process.

[0003] However, the pins of the thermal resistor are mostly flexible, and manual fixing is adopted during welding, which is difficult to fix and has low production efficiency.

[0004] Moreover, in the related art, the pins of the thermal resistor are usually welded on the pin surface of the connecting piece by means of soldering. The pin of the connecting piece is usually hard, and a relatively soft solder layer is formed on the pin surface of the connecting piece after soldering, which causes imbalance in hardness matching, stress concentration, and poor combination between the connecting piece and the solder layer, and the connection is prone to breakage. SUMMARY

[0005] The present application proposes a temperature and pressure sensor and a welding method and welding jig thereof to solve the technical problems of difficulty in fixing, low efficiency or poor combination between the connecting piece and the solder layer in the related art.

[0006] In a first aspect, an embodiment of the present application provides a welding method of a temperature and pressure sensor, comprising: fixing a plurality of groups of welding assemblies on a base of a welding jig based on the welding jig; each group of welding assemblies includes a thermal resistor and a connecting piece arranged oppositely, and a first pin of the thermal resistor and a second pin of the connecting piece are one-to-one overlapped; the second pin has a through hole; along a first direction, the size of the second pin and the size of the through hole are both greater than the size of the first pin, the first direction is parallel to the base and perpendicular to the arrangement direction of the thermal resistor and the connecting piece; the bottom surface of the second pin has a spacing from the base.

[0007] applying a molten solder ball to the overlapping area of the first pin and the second pin in each group of welding assemblies to form solder, so that a first part of the solder contacts the bottom surface of the second pin through the through hole, a second part of the solder is located in the through hole, and a third part of the solder is located on the second pin, and after solidification, an integrated welding layer is formed; the welding layer covers at least part of the overlapping area of the first pin and the second pin.

[0008] In some embodiments, fixing a plurality of groups of welding assemblies on a base of a welding jig based on the welding jig comprises: Multiple welding components are fixed on a base using a welding fixture, and the second pin and the first pin are sequentially overlapped in a direction away from the base; at least a portion of the opening area of ​​the through hole is exposed on the first pin.

[0009] And, molten solder balls are applied to the overlap area of ​​the first and second pins in each group of soldering components to form solder, such that a first portion of solder contacts the bottom surface of the second pin through a through-hole, a second portion of solder is located inside the through-hole, and a third portion of solder is located on the second pin, including: Molten solder balls are applied to the overlap area of ​​the first and second pins in each set of soldering components to form solder, such that a first portion of solder leaks through a through-hole onto the receiving groove of the base and flows to contact the bottom surface of the second pin, a second portion of solder is located in the through-hole, and a third portion of solder is located on the second pin and covers at least a portion of the overlap area of ​​the first and second pins.

[0010] In some embodiments, in the overlap region of the first pin and the second pin, the surface of the first pin is coated with a gold layer.

[0011] On the base, the orthographic projection of the first pin passes through the orthographic projection range of the edge of the through hole.

[0012] In some embodiments, multiple welding components are fixed to the base of the welding fixture based on the welding fixture, including: Multiple welding components are fixed on the base using a welding fixture, and the first and second pins are sequentially overlapped in the direction away from the base.

[0013] And, molten solder balls are applied to the overlap area of ​​the first and second pins in each group of soldering components to form solder, such that a first portion of solder contacts the bottom surface of the second pin through a through-hole, a second portion of solder is located inside the through-hole, and a third portion of solder is located on the second pin, including: Molten solder balls are applied to the overlap area of ​​the first and second pins in each set of soldering components to form solder, such that a first portion of solder leaks through a through-hole onto the receiving groove of the base and flows, covering at least a portion of the overlap area of ​​the first and second pins, a second portion of solder is located in the through-hole, and a third portion of solder is located on the second pin.

[0014] In some embodiments, a first portion of solder leaks through a via into a receiving groove on the base and flows, covering at least a portion of the overlap area of ​​the first and second pins, including: The first portion of solder leaks through the through-hole to the bottom of the receiving tank, and the fourth portion of solder leaks through the gap between the side wall of the second bearing tank of the base and the second pin to the bottom of the receiving tank, flowing and covering at least a portion of the overlapping area of ​​the first pin and the second pin.

[0015] In some embodiments, the plurality of sets of welding components are fixed on a base of a welding fixture based on the welding fixture, including: The plurality of sets of welding components are arranged in a plurality of accommodation regions of the base; in each set of welding components, the thermistor is arranged in a first bearing groove of the accommodation region, the connecting piece is arranged in a second bearing groove of the accommodation region, the first pin and the second pin are overlapped in the overlapping region of the first bearing groove and the second bearing groove, and the top of the one of the first pin and the second pin away from the base is not lower than the surface of the base.

[0016] The pressing plate of the welding fixture is rotated so that the pressing plate presses both ends of the overlapping region of the first pin and the second pin, and the hollow of the pressing plate exposes the through hole.

[0017] In some embodiments, the overlapping region of the first bearing groove and the second bearing groove has an accommodation groove.

[0018] The range of the normal projection of the through hole on the base falls within the range of the accommodation groove.

[0019] The bottom of the one of the first pin and the second pin close to the base has a spacing with the groove bottom of the accommodation groove.

[0020] In a second aspect, the embodiments of the present application provide a welding fixture used in any welding method provided in the first aspect, including: The base has a plurality of accommodation regions for one-to-one accommodating a plurality of sets of welding components; the accommodation region has a first bearing groove and a second bearing groove arranged oppositely, and the opposite end regions of the first bearing groove and the second bearing groove are overlapped.

[0021] The plurality of pressing plates are one-to-one correspondingly connected rotatably with the plurality of accommodation regions; the pressing plate has a hollow.

[0022] In the fixed state, the thermistor is at least partially arranged in the first bearing groove, the connecting piece is at least partially arranged in the second bearing groove, and the first pin and the second pin are overlapped in the overlapping region of the first bearing groove and the second bearing groove; the pressing plate presses both ends of the overlapping region of the first pin and the second pin, and the hollow of the pressing plate exposes the through hole.

[0023] In a third aspect, the embodiments of the present application provide a temperature and pressure sensor manufactured by any welding method provided in the first aspect, including: The thermistor has a first pin.

[0024] The connecting piece has a second pin; the second pin has a through hole, and the second pin is overlapped with the first pin.

[0025] The welding layer includes a part connected to both sides of the second pin and a part located in the through hole.

[0026] The welding layer covers at least part of the overlapping region of the first pin and the second pin.

[0027] In some embodiments, the solder layer includes: a first solder layer connected to one side of the second pin, a second solder layer connected to the other side of the second pin, and a third solder layer formed in the through-hole.

[0028] The first solder layer covers at least a portion of the overlap area between the first and second pins.

[0029] On a plane parallel to the second pin, the areas of the first and second solder layers are both larger than the area of ​​the third solder layer.

[0030] In some embodiments, in the overlap area of ​​the first pin and the second pin, the surface of the first pin is covered with a gold layer and passes through the opening area of ​​the via.

[0031] In some embodiments, the through hole is a round hole or an oblong hole, and the major axis of the oblong hole is aligned with the length direction of the second pin.

[0032] The beneficial effects of the technical solutions provided in this application include: (1) In the embodiments of this application, multiple welding components are fixed at the same time by using welding fixtures. Compared with manual fixing, the accuracy is higher, the stability of fixing is improved, the production efficiency is improved, and the cost is lower.

[0033] (2) In this embodiment of the application, solder ball soldering is performed on the solder assembly fixed by the soldering fixture. Molten solder balls are applied to the overlapping area of ​​the first pin of the thermistor and the second pin of the connector. The second pin is flat and has a top surface and a bottom surface (the top surface is the side away from the base when soldering, and the bottom surface is the side facing the base when soldering). The molten solder balls are applied towards the top surface of the second pin and can leak through the through hole of the second pin. The molten solder balls form liquid solder, which has fluidity. The second pin has a certain adsorption property for the solder, so that the first part of the leaked solder can contact the bottom surface of the second pin. The second part of the solder is located in the through hole, and the third part of the solder is located on the top surface of the second pin. The solder layer formed after the solder balls are solidified covers the overlapping area of ​​the first pin and the second pin and has an "I" shaped structure that is wide at both ends and narrow in the middle.

[0034] (3) The embodiments of this application can increase the bonding area between the solder layer and the first pin and the second pin, thereby improving the bonding force between the first pin and the second pin and the solder layer. Moreover, compared with the related technology where solder is applied to only one surface of the second pin, the solder layer is attached to both sides of the second pin, which can form a stable frame structure, disperse stress, reduce the possibility of cracking due to stress concentration, and improve the connection stability between the first pin and the second pin.

[0035] (4) The embodiments of this application use solder ball soldering to perform soldering. The solder ball is in a molten state before reaching the through hole and has fluidity, which can ensure that some solder balls or a part of a single solder ball can pass through the through hole and contact the bottom surface of the second pin, thus ensuring the feasibility of the soldering method.

[0036] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic flowchart illustrating the welding method for a first type of temperature and pressure sensor provided in this application embodiment; Figure 2 A schematic flowchart illustrating the welding method for a second type of temperature and pressure sensor provided in this application embodiment; Figure 3 A schematic flowchart illustrating the welding method for a third type of temperature and pressure sensor provided in this application embodiment; Figure 4 One of the structural schematic diagrams of the second type of temperature and pressure sensor welding method provided in the embodiments of this application, after fixing multiple sets of welding components on the base of the welding fixture; Figure 5 for Figure 4 A magnified view of a section at point A in the middle; Figure 6 The second schematic diagram of the structure after fixing multiple welding components onto the base of the welding fixture in the welding method of the second temperature and pressure sensor provided in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of a welding fixture provided in an embodiment of this application; Figure 8 for Figure 7 A magnified view of a section at point B in the middle; Figure 9 for Figure 7 A magnified view of a section at point C; Figure 10 This is a schematic diagram of the structure after multiple welding components are fixed on the base of the welding fixture in the third welding method for the temperature and pressure sensor provided in the embodiments of this application. Figure 11A structure schematic diagram of a temperature and pressure sensor provided by an embodiment of the present application; Figure 12 For Figure 11 A structure schematic diagram of a cross section at DD' in the middle.

[0039] Reference signs: 100-welding fixture; 10-base; 11-receiving area; 111-first bearing groove; 112-second bearing groove; 113-receiving groove; 20-pressing plate; 21-hollow; 200-welding assembly; 210-thermistor; 211-first pin; 212-gold layer; 220-connector; 221-second pin; 222-via hole; 300-welding layer; 310-first solder layer; 320-second solder layer; 330-third solder layer. DETAILED DESCRIPTION

[0040] The embodiments of the present application will be described below in conjunction with the accompanying drawings. It should be understood that the embodiments described below in conjunction with the accompanying drawings are exemplary descriptions of the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0041] Those skilled in the art can understand that, unless specifically stated otherwise, "said" and "the" used herein can also include plural forms. It should be further understood that the wording "comprising" used in the specification of the present application means that the features, integers, steps, operations, elements and / or components exist, but does not exclude other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the present technical field. It should be understood that when we say that an element is "connected" to another element, the element can be directly connected to the other element, or it can mean that the element and the other element are connected through an intermediate element. The term "and / or" used herein means at least one of the items defined by the term, for example, "A and / or B" can be implemented as "A", or as "B", or as "A and B".

[0042] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in further detail below in conjunction with the accompanying drawings.

[0043] The first welding method of the temperature and pressure sensor provided by the embodiments of the present application, the flowchart of the method is shown as Figure 1 The method comprises steps S1-S2: S1: Fix multiple groups of welding assemblies 200 on the base 10 of the welding fixture 100 based on the welding fixture 100. Each group of welding assemblies 200 includes a thermistor 210 and a connecting piece 220 arranged oppositely, and the first pin 211 of the thermistor 210 and the second pin 221 of the connecting piece 220 are correspondingly overlapped; the second pin 221 has a through hole 222; along the first direction, the size of the second pin 221 and the size of the through hole 222 are both larger than the size of the first pin 211, and the first direction is parallel to the base 10 and perpendicular to the arrangement direction of the thermistor 210 and the connecting piece 220; the bottom surface of the second pin 221 has a spacing with the base 10.

[0044] S2: Apply molten tin balls to the overlapping area of the first pin 211 and the second pin 221 in each group of welding assemblies 200 to form solder, so that the first part of the solder contacts the bottom surface of the second pin 221 through the through hole 222, the second part of the solder is located in the through hole 222, and the third part of the solder is located on the second pin 221, and after solidification, an integrated solder layer 300 is formed. The solder layer 300 covers at least part of the overlapping area of the first pin 211 and the second pin 221.

[0045] Please refer to Figure 4 , Figure 4 The thermistor 210 and the connecting piece 220 are fixed on the base 10 of the welding fixture 100. Figure 4 The welding fixture 100 in the figure simultaneously fixes multiple groups of welding assemblies 200, for the convenience of display, Figure 4 The second pressing plate 20 of the first row is in a raised state, and the other pressing plates 20 are in a state of pressing the welding assemblies 200.

[0046] In this embodiment, by using the welding fixture 100 to simultaneously fix multiple groups of welding assemblies 200, compared with manual fixing, the precision is higher, the stability of fixing can be improved, the production efficiency can be improved, and the cost is lower.

[0047] In this embodiment, solder ball soldering is performed on the soldering assembly 200 fixed in the soldering fixture 100. Molten solder balls are applied to the overlapping area of ​​the first pin 211 of the thermistor 210 and the second pin 221 of the connector 220. The second pin 221 is flat and has opposing top and bottom surfaces (the top surface is the side away from the base 10 during soldering, and the bottom surface is the side facing the base 10 during soldering). The molten solder balls are applied towards the top surface of the second pin 221 and can pass through the second pin 221. The molten solder ball leaks through the through-hole 222, forming liquid solder. This liquid solder is fluid, and the second pin 221 has a certain adsorption capacity for the solder, allowing the first part of the leaked solder to contact the bottom surface of the second pin 221. The second part of the solder is located inside the through-hole 222, and the third part of the solder is located on the top surface of the second pin 221. After the solder solidifies, the weld layer 300 formed covers the overlapping area of ​​the first pin 211 and the second pin 221, forming an "I" shaped structure that is wide at both ends and narrow in the middle.

[0048] This embodiment increases the bonding area between the solder layer 300 and the first pin 211 and the second pin 221, thereby improving the bonding force between the first pin 211, the second pin 221, and the solder layer 300. Furthermore, compared to related technologies where solder is applied only to one surface of the second pin 221, the solder layer 300 is bonded to both sides of the second pin 221, forming a stable frame structure, dispersing stress, reducing the possibility of breakage due to stress concentration, and improving the connection stability between the first pin 211 and the second pin 221.

[0049] This embodiment uses a solder ball soldering method. When the size of the solder ball is larger than the size of the through hole 222, the solder ball is in a molten state before reaching the through hole 222, exhibiting fluidity. This ensures that at least a portion of a single solder ball can pass through the through hole 222 and contact the bottom surface of the second pin 221, guaranteeing the feasibility of the soldering method. For example, if the solder ball diameter is 1.2 mm and the opening diameter of the through hole 222 is 0.25 mm, the solder portion formed after the solder ball melts passes through the through hole 222 and contacts the bottom surface of the second pin 221, with some remaining inside the through hole 222 and some connected to the second pin 221.

[0050] When the size of the solder ball is no larger than the size of the through-hole 222, due to surface tension, a single molten solder ball can maintain a relatively consistent shape and size with its original size when it reaches the through-hole 222. This allows the single solder ball to pass through the through-hole 222 and contact the bottom surface of the second pin 221, ensuring the feasibility of the soldering method. For example, if the solder ball diameter is 1.2 mm and the opening diameter of the through-hole 222 is 0.25 mm, the solder portion formed after the solder ball melts will pass through the through-hole 222 and contact the bottom surface of the second pin 221, with some remaining inside the through-hole 222 and some connected to the second pin 221.

[0051] For example, the diameter of the solder ball is 0.2mm, and the diameter of the opening of the through hole 222 is 0.25mm. The partial solder ball can pass through the through hole 222 and contact the bottom surface of the second pin 221. The partial solder ball remains in the through hole 222, and the partial solder ball is connected to the second pin 221.

[0052] It can be understood that the solder ball is in a liquid state after melting. After melting, the plurality of solder balls form at least one group of liquid solder with fluidity. The first part of the solder can be formed by a part of a solder ball or by a plurality of solder balls. Similarly, the second part of the solder can be formed by a part of a solder ball or by a plurality of solder balls. The third part of the solder can be formed by a part of a solder ball or by a plurality of solder balls.

[0053] Please refer to Figures 4-5 、 Figures 7-9 , Figure 4 FIG. 6 is a structural schematic diagram of the solder fixture 100 after fixing the plurality of solder assemblies 200 on the base 10 of the solder fixture 100, Figure 5 FIG. 7 is a partial enlarged view of position A in FIG. 6, Figure 4 FIG. 8 is a structural schematic diagram of the solder fixture 100, Figure 7 FIG. 9 is a partial enlarged view of position B in FIG. 8, Figure 8 FIG. 10 is a partial enlarged view of position C in FIG. 8. Figure 7 Figure 9 Figure 7

[0054] In some embodiments, the fixing of the plurality of solder assemblies 200 on the base 10 of the solder fixture 100 in step S1 is specifically as follows: The plurality of solder assemblies 200 are arranged in the plurality of accommodation areas 11 of the base 10. In each solder assembly 200, the thermistor 210 is arranged in the first bearing groove 111 of the accommodation area 11, the connecting piece 220 is arranged in the second bearing groove 112 of the accommodation area 11, the first pin 211 and the second pin 221 are overlapped in the overlapping area of the first bearing groove 111 and the second bearing groove 112, and the top of the one of the first pin 211 and the second pin 221 away from the base 10 is not lower than the surface of the base 10.

[0055] The pressing plate 20 of the solder fixture 100 is rotated to press the two ends of the overlapping area of the first pin 211 and the second pin 221, and the hollow 21 of the pressing plate 20 exposes the through hole 222.

[0056] In the embodiment, as Figures 4-5 、 Figures 7-9 ​​​As shown, the welding jig 100 comprises a base 10 and a plurality of pressing plates 20 rotatably connected with the base 10, the surface of the base 10 is provided with a plurality of accommodation areas 11, each of which is provided with a first bearing groove 111 and a second bearing groove 112 arranged oppositely, the inside of the first bearing groove 111 is provided with a structure matching the shape of the thermistor 210, and the thermistor 210 can be fixed therein, and the inside of the second bearing groove 112 is provided with a structure matching the shape of the connecting piece 220, and the connecting piece 220 can be fixed therein. The fixing mode of the embodiment is simple and convenient to operate, and has strong effectiveness.

[0057] In the embodiment, the overlapping area of the first pin 211 and the second pin 221 is pressed by the pressing plate 20, which can further fix the overlapping area of the first pin 211 and the second pin 221 on the basis of the thermistor 210 and the connecting piece 220 being fixed by the base 10, ensure the effective overlapping of the first pin 211 and the second pin 221, and further ensure the yield of subsequent welding, and also enable the first pin 211 and the second pin 221 to maintain the shape when leaving the factory, thereby reducing the possibility of deformation of the first pin 211 and the second pin 221 during the fixing process.

[0058] It can be understood that, as shown in the drawings, Figure 5 The first pin 211 has two, the second pin 221 has two, and the first pin 211 and the second pin 221 are one-to-one overlapped, that is, when the thermistor 210 and the connecting piece 220 are arranged oppositely, one first pin 211 arranged oppositely is overlapped with one second pin 221, and the other first pin 211 arranged oppositely is overlapped with the other second pin 221. Moreover, when overlapped, the first pin 211 can be located above (i.e., away from the surface of the base 10), or the second pin 221 can be located above.

[0059] In the embodiment, the first pin 211 and the second pin 221 are arranged in the first bearing groove 111 and the second bearing groove 112 respectively, when the first pin 211 and the second pin 221 are overlapped, the top of the one away from the base 10 is not lower than the surface of the base 10, which ensures that the pressing plate 20 can contact and abut against the one of the first pin 211 and the second pin 221 away from the base 10, and ensures the effectiveness of the pressing plate 20.

[0060] In some embodiments, after step S1 described above, the welding fixture 100 carrying the welding assembly 200 is placed entirely in a welding machine, and molten solder balls are applied to the overlapping area of ​​the first pin 211 and the second pin 221. Solder balls can be applied sequentially to each overlapping area, or solder balls can be applied to multiple overlapping areas simultaneously. The solder balls have high precision and small size, and there is a gap between the second pins 221 of each connector 220, which is much larger than the size of the solder balls, thereby reducing the risk of short circuits caused by soldering between the second pins 221 of the connectors 220.

[0061] For example, the size of the solder ball is between 0.1 mm and 1.2 mm, and the size between the second pin 221 is 2 mm, which is larger than the size of the solder ball, thus reducing the risk of short circuit.

[0062] In some embodiments, such as Figures 5-9 As shown, a receiving groove 113 is provided in the overlapping area of ​​the first bearing groove 111 and the second bearing groove 112; the orthographic projection of the through hole 222 on the base 10 falls within the range of the receiving groove 113. The bottom of the one of the first pin 211 and the second pin 221 closest to the base 10 is spaced from the bottom of the receiving groove 113.

[0063] In this embodiment, the end of the first support groove 111 facing the second support groove 112 is used to accommodate the first pin 211, and the end of the second support groove 112 facing the first support groove 111 is used to accommodate the second pin 221. The opposite ends of the first support groove 111 and the second support groove 112 overlap, and there is a receiving groove 113 in the overlapping area. The overlapping area of ​​the first pin 211 and the second pin 221 is located within the receiving groove 113. Compared with the area in the first support groove 111 where the first pin 211 is located (excluding the receiving groove 113), and also compared with the area in the second support groove 112 where the second pin 221 is located (excluding the receiving groove 113), the receiving groove 113 is deeper and closer to the pin (first pin 211 or second pin 221) of the base 10, and there is a gap between the pin and the bottom of the receiving groove 113 of the base 10.

[0064] Therefore, the orthogonal projection of the through hole 222 on the base 10 falls within the range of the receiving groove 113, allowing the solder ball to fall from the through hole 222 into the receiving groove 113 during the soldering process. The molten solder ball can cover the pins closer to the base 10, thereby ensuring that the molten solder ball can cover the surfaces of the first pin 211 and the second pin 221 facing the bottom of the receiving groove 113, further increasing the area of ​​the first pin 211 and the second pin 221 covered by the solder ball, thereby improving the reliability of the soldering of the first pin 211 and the second pin 221.

[0065] This application also provides a second method for welding a temperature and pressure sensor, the flowchart of which is shown below. Figure 2 As shown, the method includes the following steps S3-S4: S3: Based on the welding fixture 100, fix multiple welding components 200 on the base 10 of the welding fixture 100, and in the direction away from the base 10, connect the second pin 221 and the first pin 211 in sequence; at least part of the opening area of ​​the through hole 222 is exposed on the first pin 211.

[0066] S4: Molten solder balls are applied to the overlapping area of ​​the first pin 211 and the second pin 221 in each welding assembly 200 to form solder, so that the first part of the solder leaks through the through hole 222 onto the receiving groove 113 of the base 10 and flows, contacting the bottom surface of the second pin 221. The second part of the solder is located in the through hole 222, and the third part of the solder is located on the second pin 221 and covers at least part of the overlapping area of ​​the first pin 211 and the second pin 221. After solidification, an integral welding layer 300 is formed.

[0067] In this embodiment, as Figures 4-5 As shown, when fixing the soldering assembly 200, the second pin 221 and the first pin 211 overlap sequentially in the direction away from the base 10. That is, the second pin 221 is closer to the base 10, and the first pin 211 is farther away from the base 10. In other words, when the soldering fixture 100 is upright, the first pin 211 is located above the second pin 221. The first pin 211 is thinner, and the second pin 221 is wider. The width of the first pin 211 is smaller than the diameter of the through hole 222, so that the first pin 211 does not completely cover the opening area of ​​the through hole 222, thereby ensuring that the solder ball can reach the opening of the through hole 222 and leak into the base 10.

[0068] Furthermore, the first portion of solder leaks onto and flows into the receiving tank 113, covering at least a portion of the bottom of the receiving tank 113 and contacting the bottom surface of the second pin 221. The second portion of solder remains within the through-hole 222, and the third portion of solder is located on the top surface of the second pin 221 and covers the first pin 211. After the solder solidifies, an integral solder layer 300 is formed. Therefore, the solder layer 300 can cover both the top and bottom surfaces of the second pin 221 and enclose the first pin 211, thereby improving the connection reliability of the first pin 211 and the second pin 221.

[0069] It is understood that the second pin 221 is flat, with one side being the bottom surface facing the base 10 and the other side being the top surface away from the base 10. Taking the top surface of the second pin 221 as an example, the dimension of the second pin 221 along the length direction is the length of the second pin 221, and the dimension of the second pin 221 along the width direction (i.e., the first direction) is the width of the second pin 221. The overlapping portions of the first pin 211 and the second pin 221 are parallel to each other, and the length and width directions of the first pin 211 are consistent with the length and width directions of the second pin 221.

[0070] It should be noted that in the second welding method of the temperature and pressure sensor in this embodiment, only the features that are different from the first welding method in the above embodiment are described. Other parts not described can be used interchangeably and will not be repeated here.

[0071] The research and development ideas of this application also include: the pins are generally made of copper or alloy, which are easily oxidized in the air. The oxide layer formed will hinder the wetting between the solder ball and the pin, making it difficult for the molten liquid solder to spread on the pin surface and hindering the soldering.

[0072] In some embodiments, such as Figure 6 As shown, in the overlapping area of ​​the first pin 211 and the second pin 221, the surface of the first pin 211 is covered with a gold layer 212.

[0073] On the base 10, the orthographic projection of the first pin 211 passes through the orthographic projection range of the edge of the through hole 222.

[0074] In this embodiment, the surface of the first pin 211 is coated with a gold layer 212. Gold is a very stable metal that hardly oxidizes in air. Therefore, the molten solder ball can easily spread on the metal surface and form an intermetallic compound, thereby completing the soldering.

[0075] Moreover, the gold layer 212 has a low surface energy, which helps to reduce the overall surface tension of the molten solder ball, has stronger fluidity, and is more easily drawn into the through hole 222 by capillary action, so that the solder ball can smoothly enter the through hole 222 and leak to contact the bottom surface of the second pin 221 to form an "I"-shaped solder layer 300.

[0076] This application also provides a third method for welding a temperature and pressure sensor, the flowchart of which is shown below. Figure 3 As shown, the method includes the following steps S5-S6: S5: Fix multiple welding components 200 on the base 10 of the welding fixture 100, and connect the first pin 211 and the second pin 221 in sequence along the direction away from the base 10.

[0077] S6: Apply the molten solder balls to the overlap region of the first pin 211 and the second pin 221 in each solder assembly 200 to form solder, so that a first portion of the solder leaks onto the accommodating groove 113 of the base 10 through the through hole 222 and flows to cover at least part of the overlap region of the first pin 211 and the second pin 221, a second portion of the solder is located in the through hole 222, and a third portion of the solder is located on the second pin 221, and after solidification, an integrated solder layer 300 is formed.

[0078] Different from the previous embodiment, in the present embodiment, when the solder assembly 200 is fixed, the first pin 211 and the second pin 221 are overlapped in turn in a direction away from the base 10, that is, the first pin 211 is closer to the base 10, and the second pin 221 is farther away from the base 10. In other words, when the soldering jig 100 is upright, the second pin 221 is located above the first pin 211. The first pin 211 is thinner, and the second pin 221 is wider. The width of the first pin 211 is smaller than the diameter of the through hole 222, so that the first pin 211 does not completely cover the opening region of the through hole 222, thereby ensuring that the solder balls falling from the through hole 222 can leak into the accommodating groove 113 of the base 10 through the first pin 211.

[0079] Furthermore, the first portion of the solder leaks onto the accommodating groove 113 and flows to cover at least part of the groove bottom of the accommodating groove 113 and contact both the first pin 211 and the second pin 221 to cover the overlap region of the first pin 211 and the second pin 221, the second portion of the solder is retained in the through hole 222, and the third portion of the solder is located on the top surface of the second pin 221. After the solder solidifies, an integrated solder layer 300 is formed. Therefore, the solder layer 300 can wrap the top surface and the bottom surface of the second pin 221 and wrap the first pin 211 inside, thereby improving the connection reliability of the first pin 211 and the second pin 221.

[0080] It should be noted that in the third soldering method of the temperature and pressure sensor of the present embodiment, only the features different from the first soldering method in the above-mentioned embodiments are described, and other unmentioned aspects can be shared, which will not be described here.

[0081] Optionally, when the third soldering method is used, according to the depth of the accommodating groove 113, the bottommost part of the first pin 211 can be in contact with the groove bottom of the accommodating groove 113, or can have a spacing with the groove bottom of the accommodating groove 113. When the depth of the accommodating groove 113 is relatively deep, the first pin 211 has a spacing with the groove bottom of the accommodating groove 113, so that the finally formed solder layer 300 can completely wrap the bottommost part of the first pin 211 inside, thereby wrapping the entire circumference of the first pin 211 inside, and improving the bonding force between the solder and the first pin 211.

[0082] Alternatively, when using the third welding method, the through hole 222 can be an oblong hole. A schematic diagram of the structure when the through hole 222 is an oblong hole is shown below. Figure 10 As shown. When using the third soldering method, since the overlapping area of ​​the first pin 211 and the second pin 221 is located on the bottom surface of the second pin 221, the use of an oblong hole allows more solder to leak to the bottom surface of the second pin 221, while covering the first pin 211 and the second pin 221.

[0083] In some embodiments, step S6 above, which involves causing the first portion of solder to leak through the through-hole 222 onto the receiving groove 113 of the base 10 and flow there, covering at least a portion of the overlapping area of ​​the first pin 211 and the second pin 221, specifically includes: The first portion of solder leaks through the through-hole 222 to the bottom of the receiving groove 113, and the fourth portion of solder leaks through the gap between the side wall of the second bearing groove 112 of the base 10 and the second pin 221 to the bottom of the receiving groove 113, flowing and covering at least a portion of the overlapping area of ​​the first pin 211 and the second pin 221.

[0084] In this embodiment, there is a gap between the second pin 221 and the sidewall of the second carrier groove 112. When the solder ball applied towards the overlapping area of ​​the first pin 211 and the second pin 221 forms liquid solder, the solder can leak from the gap into the receiving groove 113 and flow to cover at least a portion of the overlapping area of ​​the first pin 211 and the second pin 221, while also covering the side of the second pin 221 (i.e., the sidewall of the gap). This allows the solder layer 300 formed after the solder solidifies to cover the side of the second pin 221 on top of covering the overlapping area of ​​the first pin 211 and the second pin 221, further increasing the bonding area between the solder and the second pin 221, thereby improving the soldering reliability.

[0085] Based on the same inventive concept, this application also provides a welding fixture 100 used in any of the welding methods provided in the foregoing embodiments, and a schematic diagram of the structure of the welding fixture 100 is shown below. Figures 7-9 As shown, the welding fixture 100 includes a base 10 and a plurality of pressure plates 20.

[0086] The base 10 has multiple receiving areas 11 for accommodating multiple sets of welding components 200 in a one-to-one correspondence; each receiving area 11 has a first bearing groove 111 and a second bearing groove 112 arranged opposite to each other, and the opposite end regions of the first bearing groove 111 and the second bearing groove 112 overlap.

[0087] Multiple pressure plates 20 are rotatably connected to multiple receiving areas 11 in a one-to-one correspondence; the pressure plates 20 have hollowed-out sections 21.

[0088] In the fixed state, the thermistor 210 is at least partially arranged in the first bearing groove 111, the connecting piece 220 is at least partially arranged in the second bearing groove 112, and the first pin 211 and the second pin 221 are overlapped in the overlapping area of the first bearing groove 111 and the second bearing groove 112; the pressing plate 20 is arranged to press both ends of the overlapping area of the first pin 211 and the second pin 221, and the hollow 21 of the pressing plate 20 exposes the through hole 222.

[0089] In the embodiment, the welding jig 100 comprises a base 10 and a plurality of pressing plates 20 rotationally connected to the base 10, the surface of the base 10 has a plurality of accommodation areas 11, each of which has a first bearing groove 111 and a second bearing groove 112 arranged oppositely, the inside of the first bearing groove 111 has a structure matching the shape of the thermistor 210, which can fix the thermistor 210 inside, and the inside of the second bearing groove 112 has a structure matching the shape of the connecting piece 220, which can fix the connecting piece 220 inside. The fixing method of the embodiment is simple and effective.

[0090] In the embodiment, the overlapping area of the first pin 211 and the second pin 221 is pressed by the pressing plate 20, which can further fix the overlapping area of the first pin 211 and the second pin 221 based on the thermistor 210 and the connecting piece 220 being fixed by the base 10, ensure the effective overlapping of the first pin 211 and the second pin 221, and further ensure the yield of subsequent welding, and also enable the first pin 211 and the second pin 221 to maintain the shape when leaving the factory, thereby reducing the possibility of deformation of the first pin 211 and the second pin 221 during the fixing process.

[0091] Based on the same inventive concept, the embodiments of the present application also provide a temperature and pressure sensor manufactured by any of the welding methods provided in the foregoing embodiments, as shown in Figures 11-12 The temperature and pressure sensor comprises a thermistor 210, a connecting piece 220 and a welding layer 300.

[0092] The thermistor 210 has a first pin 211.

[0093] The connecting piece 220 has a second pin 221, the second pin 221 has a through hole 222, and the second pin 221 is overlapped with the first pin 211.

[0094] The welding layer 300 comprises a part connected to both sides of the second pin 221 and a part located in the through hole 222.

[0095] The welding layer 300 covers at least part of the overlapping area of the first pin 211 and the second pin 221.

[0096] In this embodiment, both sides of the second pin 221 are bonded with a welding layer 300, which can form a stable frame structure, disperse stress, reduce the possibility of cracking due to stress concentration, and improve the connection stability between the first pin 211 and the second pin 221.

[0097] In some embodiments, the thermistor is used to acquire temperature information; the temperature and pressure sensor also includes a pressure sensor connected to the connector 220 for acquiring pressure information.

[0098] In some embodiments, such as Figures 11-12 As shown, the solder layer 300 includes: a first solder layer 310 connected to one side of the second pin 221, a second solder layer 320 connected to the other side of the second pin 221, and a third solder layer 330 formed in the through hole 222; the first solder layer 310 covers at least a portion of the overlapping area of ​​the first pin 211 and the second pin 221; on a plane parallel to the second pin 221, the areas of the first solder layer 310 and the second solder layer 320 are both larger than the area of ​​the third solder layer 330.

[0099] In this embodiment, the first solder layer 310 covers the overlapping area of ​​the first pin 211 and the second pin 221. The first solder layer 310, the third solder layer 330, and the second solder layer 320 form an "I"-shaped structure that is wide at both ends and narrow in the middle. The "both ends" refer to the first solder layer 310 and the second solder layer 320, and the "middle" refers to the third solder layer 330. This structure can increase the bonding area between the solder layer 300 and the first pin 211 and the second pin 221, forming a stable frame structure, thereby improving the bonding force between the first pin 211 and the second pin 221 and the solder layer 300.

[0100] In some embodiments, in the overlapping area of ​​the first pin 211 and the second pin 221, the surface of the first pin 211 is covered with a gold layer 212, which passes through the opening area of ​​the through hole 222.

[0101] In this embodiment, the surface of the first pin 211 is covered with a gold layer 212, which easily forms an intermetallic compound with the solder, thereby improving the bonding force between the first pin 211 and the solder.

[0102] Moreover, the gold layer 212 has a low surface energy, which helps to reduce the overall surface tension of the molten solder ball and has stronger fluidity. The portion of the first pin 211 covered with the gold layer 212 passes through the opening area of ​​the through hole 222, making it easier for the solder to be drawn into the through hole 222 by capillary action. This allows the solder ball to smoothly enter the through hole 222 and leak out to contact the bottom surface of the second pin 221, forming an I-shaped solder layer 300.

[0103] In some embodiments, the through hole 222 is a circular hole.

[0104] In this embodiment, when the second welding method is used, the through hole 222 is a round hole, which can minimize the opening area of ​​the through hole 222 and ensure the strength of the second pin 221.

[0105] In some embodiments, such as Figure 5 As shown, the through hole 222 is an oblong hole, and the long axis of the oblong hole is consistent with the length direction of the second pin 221.

[0106] In this embodiment, as Figure 10 As shown, the through-hole 222 is an oblong hole, which allows more solder to leak into the receiving groove 113, ensuring that more solder adheres to the bottom surface of the second pin 221. The oblong hole has a major axis and a minor axis. The major axis of the oblong hole is aligned with the length direction of the second pin 221, and the minor axis is aligned with the width direction of the second pin 221. This design increases the opening area of ​​the through-hole 222 while maintaining the rigidity of the second pin 221.

[0107] By applying the embodiments of this application, at least the following beneficial effects can be achieved: (1) In this embodiment of the application, multiple welding components 200 are fixed at the same time by using welding fixture 100. Compared with manual fixing, the accuracy is higher, the stability of fixing can be improved, the production efficiency can be improved, and the cost is lower.

[0108] (2) In this embodiment of the application, solder ball soldering is performed on the soldering assembly 200 fixed in the soldering fixture 100. Molten solder balls are applied to the overlapping area of ​​the first pin 211 of the thermistor 210 and the second pin 221 of the connector 220 to form solder. The second pin 221 is flat and has a top surface and a bottom surface (the top surface is the side away from the base 10 during soldering, and the bottom surface is the side facing the base 10 during soldering). The molten solder balls are applied towards the top surface of the second pin 221, which can pass through the first pin 211 to form solder. The molten solder ball leaks through the through-hole 222 of the second pin 221. It is in a liquid state and has fluidity. The second pin 221 has a certain adsorption to the solder ball, so that the first part of the leaked solder can contact the bottom surface of the second pin 221. The second part of the solder is located inside the through-hole 222, and the third part of the solder is located on the top surface of the second pin 221. The solder layer 300 formed after the solder ball solidifies covers the overlapping area of ​​the first pin 211 and the second pin 221, forming an "I" shaped structure that is wide at both ends and narrow in the middle.

[0109] (3) The embodiments of this application can increase the bonding area between the solder layer 300 and the first pin 211 and the second pin 221, thereby improving the bonding force between the first pin 211 and the second pin 221 and the solder layer 300. Moreover, compared with the related technology where solder is applied to only one surface of the second pin 221, the solder layer 300 is attached to both sides of the second pin 221, which can form a stable frame structure, disperse stress, reduce the possibility of cracking due to stress concentration, and improve the connection stability between the first pin 211 and the second pin 221.

[0110] (4) The embodiment of this application uses solder ball soldering. The solder ball is in a molten state before reaching the through hole 222 and has fluidity, which can ensure that part of the solder ball or part of a single solder ball can pass through the through hole 222 and contact the bottom surface of the second pin 221, thus ensuring the feasibility of the soldering method.

[0111] (5) The surface of the first pin 211 is covered with a gold layer 212. Gold is a very stable metal that hardly oxidizes in air. Therefore, the molten solder ball can easily spread on the metal surface and form an intermetallic compound, thereby completing the soldering. Moreover, the surface of the gold layer 212 has a low surface energy, which helps to reduce the overall surface tension of the molten solder ball, has stronger fluidity, and is more easily drawn into the through hole 222 by capillary action, thereby allowing the solder ball to smoothly enter the through hole 222 and leak to contact the bottom surface of the second pin 221, forming an "I"-shaped solder layer 300.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A welding method for a temperature and pressure sensor, characterized in that, include: Multiple welding components are fixed to the base of a welding fixture. Each welding component includes a thermistor and a connector arranged opposite to each other, with the first pin of the thermistor and the second pin of the connector overlapping each other. The second pin has a through hole. Along a first direction, the size of the second pin and the size of the through hole are both larger than the size of the first pin. The first direction is parallel to the base and perpendicular to the arrangement direction of the thermistor and the connector. The bottom surface of the second pin is spaced from the base. Molten solder balls are applied to the overlap area of ​​the first pin and the second pin in each group of the soldering components to form solder, such that a first portion of solder contacts the bottom surface of the second pin through the through hole, a second portion of solder is located inside the through hole, and a third portion of solder is located on the second pin, and after solidification, an integral solder layer is formed; the solder layer covers at least a portion of the overlap area of ​​the first pin and the second pin.

2. The welding method according to claim 1, characterized in that, Multiple welding components are fixed to the base of the welding fixture based on the welding fixture, including: Multiple sets of welding components are fixed on the base based on the welding fixture, and the second pin and the first pin are sequentially overlapped in a direction away from the base; at least a portion of the opening area of ​​the through hole is exposed on the first pin; And, molten solder balls are applied to the overlap area of ​​the first and second pins in each group of the soldering components to form solder, such that a first portion of solder contacts the bottom surface of the second pin through the through-hole, a second portion of solder is located within the through-hole, and a third portion of solder is located on the second pin, including: Molten solder balls are applied to the overlap area of ​​the first and second pins in each set of soldering components to form solder, such that a first portion of solder leaks through the through hole to the receiving groove of the base and flows, contacting the bottom surface of the second pin, a second portion of solder is located in the through hole, and a third portion of solder is located on the second pin and covers at least a portion of the overlap area of ​​the first and second pins.

3. The welding method according to claim 2, characterized in that, In the overlapping area between the first pin and the second pin, the surface of the first pin is covered with a gold layer; On the base, the orthographic projection of the first pin passes through the orthographic projection range of the edge of the through hole.

4. The welding method according to claim 1, characterized in that, Multiple welding components are fixed to the base of the welding fixture based on the welding fixture, including: Multiple sets of welding components are fixed on the base based on the welding fixture, and the first pin and the second pin are sequentially overlapped in a direction away from the base; And, molten solder balls are applied to the overlap area of ​​the first and second pins in each group of the soldering components to form solder, such that a first portion of solder contacts the bottom surface of the second pin through the through-hole, a second portion of solder is located within the through-hole, and a third portion of solder is located on the second pin, including: Molten solder balls are applied to the overlap area of ​​the first and second pins in each set of soldering components to form solder, such that a first portion of solder leaks through the through-hole onto the receiving groove of the base and flows, covering at least a portion of the overlap area of ​​the first and second pins, a second portion of solder is located in the through-hole, and a third portion of solder is located on the second pin.

5. The welding method according to claim 4, characterized in that, This allows a first portion of solder to leak through the through-hole into the receiving groove of the base and flow, covering at least a portion of the overlap area of ​​the first pin and the second pin, including: The first portion of solder leaks through the through hole to the bottom of the receiving tank, and the fourth portion of solder leaks through the gap between the side wall of the second bearing tank of the base and the second pin to the bottom of the receiving tank, flowing and covering at least a portion of the overlapping area of ​​the first pin and the second pin.

6. The welding method according to claim 1, characterized in that, Multiple welding components are fixed to the base of the welding fixture based on the welding fixture, including: Multiple sets of the welding components are disposed in multiple receiving areas of the base; in each set of the welding components, the thermistor is disposed in the first bearing groove of the receiving area, the connector is disposed in the second bearing groove of the receiving area, the first pin and the second pin overlap in the overlapping area of ​​the first bearing groove and the second bearing groove, and the top of the one of the first pin and the second pin that is away from the base is not lower than the surface of the base; Rotate the pressure plate of the welding fixture so that the pressure plate presses down on both ends of the overlapping area of ​​the first pin and the second pin, and the through hole of the pressure plate exposes the through hole.

7. The welding method according to claim 6, characterized in that, The overlapping area of ​​the first bearing groove and the second bearing groove has a receiving groove; The orthographic projection of the through hole on the base falls within the range of the receiving groove; The bottom of the one of the first pin and the second pin closest to the base is spaced apart from the bottom of the receiving groove.

8. A welding fixture for use in the welding method as described in any one of claims 1-7, characterized in that, include: The base has multiple accommodating areas for accommodating multiple sets of the welding components in a corresponding manner; The accommodating area has a first bearing groove and a second bearing groove arranged opposite to each other, and the opposite end regions of the first bearing groove and the second bearing groove overlap. Multiple pressure plates are rotatably connected to each of the multiple receiving areas; The pressure plate has a perforation; In a fixed state, the thermistor is at least partially disposed in the first bearing groove, the connector is at least partially disposed in the second bearing groove, and the first pin and the second pin overlap in the overlapping area of ​​the first bearing groove and the second bearing groove; the pressure plate presses down on both ends of the overlapping area of ​​the first pin and the second pin, and the hollow of the pressure plate exposes the through hole.

9. A temperature and pressure sensor manufactured by the welding method as described in any one of claims 1-7, characterized in that, include: Thermistor, having a first pin; A connector having a second pin; the second pin having a through hole, the second pin overlapping the first pin; The solder layer includes portions connecting both sides of the second pin and portions located within the through-hole; The solder layer covers at least a portion of the overlap area between the first pin and the second pin.

10. The temperature and pressure sensor according to claim 9, characterized in that, The solder layer includes: a first solder layer connected to one side of the second pin, a second solder layer connected to the other side of the second pin, and a third solder layer formed in the through hole; The first solder layer covers at least a portion of the overlap area between the first pin and the second pin; On a plane parallel to the second pin, the areas of both the first and second solder layers are larger than the area of ​​the third solder layer.

11. The temperature and pressure sensor according to claim 9, characterized in that, In the overlapping area of ​​the first pin and the second pin, the surface of the first pin is covered with a gold layer and passes through the opening area of ​​the through hole.

12. The temperature and pressure sensor according to claim 9, characterized in that, The through hole is a round hole or an oblong hole, and the long axis direction of the oblong hole is consistent with the length direction of the second pin.

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