Battery assembly assembling method

Abstract

The invention relates to a battery assembly assembling method, which comprises a circuit board assembly and a battery core assembly and sequentially comprises the following steps of wiping of components, welding of the circuit board assembly, assembling of the battery core assembly, spot welding of nickel sheets, installation of the circuit board assembly and laser welding of connecting sheets and pins. The battery assembly has the advantages that the battery assembly is formed through the assembly methods of wiping of the components, welding of the circuit board assembly, assembly of the battery core assembly, spot welding of the nickel sheets, installation of the circuit board assembly and laser welding of the connecting sheets and the pins, the assembly process of the circuit board and the battery core assembly is simplified, and the assembly efficiency of the whole battery assembly is greatly improved; besides, the welding of the circuit board assembly is arranged before the spot welding of the nickel sheet, and the welded circuit board can be cooled while the spot welding of the nickel sheet is carried out, so that the installation quality of the circuit board in the step 5 is ensured, and the assembly time of the whole battery assembly is not increased.

Description

Technical Field

[0001] The present invention relates to a method for assembling a battery component. Background Art

[0002] Wireless power tools and other wireless devices use rechargeable battery packs as power sources. These battery packs are usually detachably connected to other tools or devices. The battery packs can be repeatedly charged and discharged to allow users to reuse the tools without having to purchase a new power source.

[0003] With the continuous development of battery packs, the connection structure between the circuit board and the battery component has become increasingly important. For example, a Chinese patent with the application number 2023233651493 discloses a connection structure between a circuit board and a connector and a battery pack. Specifically, the pins of the connector pass through the vias of the circuit board and are soldered to the pads. The above connection structure has the following defects: when installing the circuit board, the vias need to be aligned with the pins, and the installation accuracy is high. Moreover, for the soldering connection structure, the operation level of the operator is required to be relatively high. If the operation is improper, it may lead to poor welding quality, such as problems of solder not filling the gap, air holes, and cracks, resulting in short circuits, virtual soldering, and cracking of the solder joints, thus affecting the performance of the circuit board. In addition, soldering operations cause environmental pollution and health hazards, which are not conducive to long-term operation. The above assembly process has the following problems: when spot-welding the connector and the battery, the circuit board needs to be installed on the battery holder, which is likely to cause damage to the circuit board during spot-welding, greatly affecting the service life of the circuit board. Moreover, the entire assembly process is complex and the work intensity is high. Summary of the Invention

[0004] The object of the present invention is to solve the problem that the existing process of connecting the circuit board and the battery cell component by soldering leads to low assembly efficiency of the entire battery component, and to propose a method for assembling a battery component. The battery component obtained by an assembly method that sequentially includes wiping of components, soldering of the circuit board component, assembly of the battery cell component, spot-welding of nickel sheets, installation of the circuit board component, and laser welding of the connection piece and the pin simplifies the assembly process of the circuit board and the battery cell component, greatly improves the assembly efficiency of the entire battery component, and can improve the connection quality between the circuit board and the battery cell component.

[0005] To solve the above technical problems, the present invention is realized through the following technical solutions: A method for assembling a battery component, including a circuit board component and a battery cell component. The battery cell component includes a bracket and a plurality of battery cells arranged in the bracket. Nickel sheets are provided on the battery cells, and pins are provided on the nickel sheets. A positioning frame for installing the pins is provided on the bracket. The circuit board component includes a circuit board and a connection piece provided at the bottom end of the circuit board. Elastic clamping members are provided on the bracket. The connection piece and the pin are fixedly connected by laser welding. A connection groove is provided on the side wall of the circuit board. The method for assembling the battery component sequentially includes the following steps: Step 1: Cut the length of the connecting piece according to the length of the pin, and use a cleaner to wipe the surfaces of the connecting piece, nickel piece, pin and circuit board respectively to remove surface oil stains, oxide layers and contaminants; Step 2: Solder the connecting piece wiped in Step 1 onto the circuit board through wave soldering to obtain a circuit board assembly; Step 3: Install multiple battery cells into a bracket to obtain a battery cell assembly, and the pole columns on the same side of the multiple battery cells are the same; Step 4: Install the nickel piece wiped in Step 1 onto the battery cell assembly obtained in Step 3, and ensure that the bottom end of the pin fits on the positioning frame, and then spot-weld the nickel piece to the battery cell through a spot welder; Step 5: Install the circuit board assembly obtained in Step 2 onto the battery cell assembly soldered in Step 4, and make the connecting piece fit on the pin; Step 6: Use a laser to fix the connecting piece on the pin through laser welding to obtain a battery assembly.

[0006] Preferably, the length of the pin is L 0 , and the length of the connecting piece is L 1 , where: 1.9L 0 ≤ L 1 ≤2.1L 0 , and the cleaner in Step 1 includes alcohol or / and a detergent.

[0007] Preferably, the connecting piece and the circuit board in Step 2 are wave soldered using a wave soldering machine, and the wave soldering includes the following steps: Step 20: Place the wiped circuit board on the conveyor chain of the wave soldering machine, and set the driving speed of the conveyor chain, and the driving speed of the conveyor chain is 1150 - 1250 mm / min; Step 21: Uniformly apply a soldering flux on the circuit board through a nozzle, and the specific gravity of the soldering flux is 0.8 - 0.82; Step 22: Transfer the circuit board processed in Step 21 to a preheating oven for preheating treatment, the preheating temperature is 110 - 135 °C, the preheating oven includes a first preheating zone, a second preheating zone and a third preheating zone, and the preheating temperature of the first preheating zone is 110 - 118 °C, the preheating temperature of the second preheating zone is 119 - 128 °C, and the preheating temperature of the third preheating zone is 129 - 135 °C; Step 23: Perform wave soldering treatment on the circuit board preheated in Step 22, and the temperature of the wave soldering tank is 250 - 260 °C; Step 24: Cool the circuit board after wave soldering, and the cooling time is 12 - 15 min.

[0008] Preferably, in step four, the temperature of the spot welder is 420 - 480 °C, the spot welding current of the spot welder is 2.4 - 2.5 KA, the pre-pressure time is 100 - 110 ms, the spot welding time is 0.07 - 0.09 ms, and the pressure holding time is 200 - 230 ms.

[0009] Preferably, in step six, the no-load jump speed of the laser is 400 - 410 mm / s, the laser power is 60 - 70 W, the welding speed is 135 - 140 mm / s, the laser pulse frequency is 65 - 75 KHZ, the duration of the laser pulse is 0.45 - 0.55 μs, the weld seam is a straight weld seam, and the width of the weld seam is 0.35 - 0.4 mm, and the depth of the weld seam is 0.12 - 0.15 mm.

[0010] Preferably, the length of the connecting groove is L 2 , where: 1.3L 0 ≤ L 2 ≤ 1.4L 0 , and the width of the connecting groove is equal to the width of the connecting piece.

[0011] Preferably, the circuit board is provided with a positioning groove adapted to the connecting piece, and the connecting piece is a copper-tin alloy connecting piece or a nickel-plated steel strip connecting piece or a nickel connecting piece, and the thickness of the connecting piece is equal to the thickness of the pin.

[0012] Preferably, a positioning structure is provided between the bracket and the circuit board, and the positioning structure includes a positioning post and a positioning hole connected to each other.

[0013] Preferably, the positioning post is arranged on the bracket, and the positioning post is arranged in the vertical direction or the horizontal direction, the positioning hole is arranged on the circuit board, and the top end of the positioning post is provided with an arc chamfer.

[0014] Preferably, the bracket includes a left mounting frame and a right mounting frame. Both the left mounting frame and the right mounting frame are provided with mounting holes for mounting the battery cell. Both the left mounting frame and the right mounting frame are provided with an elastic clamping member. The elastic clamping member includes a locking block and a spring piece. The locking block is fixedly connected to the left mounting frame and the right mounting frame through the spring piece, and the locking block is provided with an inclination angle.

[0015] In summary, the advantages of the present invention are as follows: The battery assembly obtained by the assembly method of wiping components, soldering circuit board components, assembling cell components, spot welding nickel sheets, installing circuit board components, and laser welding connecting pieces and pins simplifies the assembly process of the circuit board and the cell components, greatly improves the assembly efficiency of the entire battery assembly, and can improve the connection quality between the circuit board and the cell components. In addition, the soldering of the circuit board components is set before the spot welding of the nickel sheets, and the soldered circuit board can be cooled while the nickel sheets are being spot welded, ensuring the installation quality of the circuit board in step five without increasing the assembly time of the entire battery assembly. Specifically, by wiping the components in step one, it can ensure that the surfaces of the connecting pieces, nickel sheets, pins, and circuit boards are free of oil stains, oxide layers, and contaminants, improving the subsequent soldering quality. The length of the connecting piece is cut according to the length of the pins. On the one hand, it can effectively ensure the soldering quality between the connecting piece and the circuit board, and on the other hand, it can ensure the contact area between the pin and the connecting piece. The connecting piece is soldered to the circuit board by wave soldering, which can effectively eliminate the interference and influence of human factors on product quality, greatly improve the soldering quality, and wave soldering can reduce the emission of smoke and harmful gases, improve the operating environment, and be beneficial to the physical and mental health of the operator. Through steps three and four, the assembly of the cell components and the spot welding of the nickel sheets are completed. Since the connecting piece is arranged at the bottom end of the circuit board, there is no need to process vias on the circuit board for the pins to pass through. When the nickel sheet is spot welded to the cell, there is no need to install the circuit board on the bracket. The spot welding of the nickel sheet and the installation of the circuit board are two independent processes, thus reducing the damage to the circuit board during the spot welding of the nickel sheet and improving the service life of the circuit board. It not only simplifies the installation process of the circuit board but also simplifies the installation structure of the pins, greatly increasing the contact area between the pins and the connecting piece and also providing a certain protection for the connecting piece. The fixed connection between the connecting piece and the pin is achieved by laser welding. Since laser welding has the advantages of fast speed, high efficiency, and good quality, it can achieve the rapid connection between the connecting piece and the pin, and can also improve the soldering quality between the connecting piece and the pin, avoiding the phenomena of molten solder and de-soldering of the weld seam in a high-temperature environment, greatly improving the use performance of the circuit board. Moreover, the weld seam is flat and smooth, without defects such as pores and cracks, with good appearance, and the welding stress and deformation are small during welding, further improving the connection quality between the connecting piece and the pin. The setting of the elastic clip can quickly clamp the circuit board on the bracket, avoiding the movement of the circuit board during the welding process and improving the welding efficiency. On the other hand, since the connecting piece fits on the pin when the circuit board is snapped into the elastic clip, there will be no gap between the connecting piece and the pin, further improving the quality of the weld seam. Moreover, the weld seam is set in different shapes according to actual requirements to meet different welding needs. Finally, a connection groove is provided on the side wall of the circuit board to facilitate the passage of the laser beam, so that the circuit board will not cause spatial interference to the laser welding, realizing the rapid welding and fixing of the connecting piece and the pin. On the other hand, it will not reduce the overall installation strength of the circuit board.Moreover, the connection groove is convenient to process and will not affect the installation and fixation of other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings: Figure 1 is a flowchart of a battery module assembly method of the present invention; Figure 2 is a schematic structural diagram of the battery module after assembly of the present invention; Figure 3 is a schematic structural diagram of the circuit board module of the present invention; Figure 4 is a schematic structural diagram of the welding of the circuit board and the nickel sheet of the present invention; Figure 5 is a schematic structural diagram of the battery cell module of the present invention; Figure 6 is a flowchart of step two of the present invention.

[0017] Reference Signs: 1 circuit board module, 10 circuit board, 101 connection groove, 102 positioning groove, 11 connection piece, 2 battery cell module, 21 bracket, 210 positioning bracket, 211 left mounting bracket, 212 right mounting bracket, 213 mounting hole, 22 battery cell, 23 elastic clamping member, 231 locking block, 232 elastic piece, 233 inclination angle, 3 nickel sheet, 31 pin, 4 positioning structure, 41 positioning post, 42 positioning hole, 43 arc chamfer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] As Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 shown, a battery module assembly method includes a circuit board module 1 and a battery cell module 2. The battery cell module 2 includes a bracket 21 and a plurality of battery cells 22 disposed in the bracket. A nickel sheet 3 is provided on the battery cell, and a pin 31 is provided on the nickel sheet 3. A positioning bracket 210 for mounting the pin is provided on the bracket. The circuit board module 1 includes a circuit board 10 and a connection piece 11 disposed on the circuit board. An elastic clamping member 23 is provided on the bracket. When the circuit board 10 is snapped into the elastic clamping member 23, the connection piece 11 is in contact with the pin 31, and the connection piece 11 and the pin 31 are fixedly connected by laser welding. A connection groove 101 is provided on the side wall of the circuit board 10. The battery module assembly method sequentially includes the following steps: Step 1: Cut the length of the connection piece according to the length of the pin, and use a cleaner to wipe the surfaces of the connection piece, nickel sheet, pin, and circuit board respectively to remove surface oil stains, oxide layers, and contaminants; Step 2: Solder the connecting piece wiped in Step 1 onto the circuit board through wave soldering to obtain a circuit board assembly; Step 3: Install multiple battery cells into a bracket to obtain a battery cell assembly, and the pole columns on the same side of the multiple battery cells are the same; Step 4: Install the nickel sheet wiped in Step 1 onto the battery cell assembly obtained in Step 3, and ensure that the bottom end of the pin fits on the positioning frame. Then, spot-weld the nickel sheet onto the battery cell through a spot welder. The temperature of the spot welder is 420 - 480 °C, the spot welding current of the spot welder is 2.4 - 2.5 KA, the pre-pressure time is 100 - 110 ms, the spot welding time is 0.07 - 0.09 ms, and the pressure-holding time is 200 - 230 ms; Step 5: Install the circuit board assembly obtained in Step 2 onto the battery cell assembly welded in Step 4, and make the connecting piece fit on the pin; Step 6: Use a laser to fix the connecting piece on the pin through laser welding to obtain a battery assembly. The no-load jump speed of the laser is 400 - 410 mm / s, the laser power is 60 - 70 W, the welding speed is 135 - 140 mm / s, the laser pulse frequency is 65 - 75 KHZ, and the duration of the laser pulse is 0.45 - 0.55 μs.

[0019] In this embodiment, the temperature of the spot welder is 445 °C, the spot welding current of the spot welder is 2.5 KA, the pre-pressure time is 110 ms, the spot welding time is 0.07 ms, and the pressure-holding time is 200 ms, or the temperature of the spot welder is 460 °C, the spot welding current of the spot welder is 2.4 KA, the pre-pressure time is 100 ms, the spot welding time is 0.07 ms, and the pressure-holding time is 230 ms. The no-load jump speed of the laser is 400 mm / s, the laser power is 64 W, the welding speed is 135 mm / s, the laser pulse frequency is 70 KHZ, and the duration of the laser pulse is 0.5 μs.

[0020] The battery assembly obtained by the assembly method of wiping components, soldering circuit board components, assembling cell components, spot welding nickel sheets, installing circuit board components, and laser welding connecting pieces and pins simplifies the assembly process of the circuit board and the cell components, greatly improves the assembly efficiency of the entire battery assembly, and can improve the connection quality between the circuit board and the cell components. In addition, setting the soldering of the circuit board components before the spot welding of the nickel sheets can complete the cooling treatment of the soldered circuit board while the nickel sheets are being spot welded, ensuring the installation quality of the circuit board in step five without increasing the assembly time of the entire battery assembly. Specifically, by wiping the components in step one, it can ensure that the surfaces of the connecting pieces, nickel sheets, pins, and circuit boards are free of oil stains, oxide layers, and contaminants, improving the subsequent soldering quality. And by cutting the length of the connecting piece according to the length of the pins, on the one hand, it can effectively ensure the soldering quality between the connecting piece and the circuit board, and on the other hand, it can ensure the contact area between the pin and the connecting piece. Soldering the connecting piece to the circuit board by wave soldering can effectively eliminate the interference and influence of human factors on product quality, greatly improve the soldering quality, and wave soldering can reduce the emission of smoke and harmful gases, improving the operating environment and being beneficial to the physical and mental health of the operator. Through steps three and four, the assembly of the cell components and the spot welding of the nickel sheets are completed. Since the connecting piece is arranged at the bottom of the circuit board, there is no need to process vias on the circuit board for the pins to pass through. When the nickel sheet is spot welded to the cell, there is no need to install the circuit board on the bracket. The spot welding of the nickel sheet and the installation of the circuit board are two independent processes, thus reducing the damage to the circuit board during the spot welding of the nickel sheet and improving the service life of the circuit board. It not only simplifies the installation process of the circuit board but also simplifies the installation structure of the pins, greatly increasing the contact area between the pins and the connecting piece and also playing a certain protective role for the connecting piece. In addition, the temperature of the spot welder is 420 - 480 °C, the spot welding current of the spot welder is 2.4 - 2.5 KA, the pre-pressure time is 100 - 110 ms, and the spot welding time is 0.07 - 0.09 ms, the holding pressure time is 200 - 230 ms, which can greatly improve the quality of spot welding. The fixed connection between the connecting piece and the pin is realized through laser welding. Since laser welding has the advantages of fast speed, high efficiency and good quality, the quick connection between the connecting piece and the pin can be achieved, and the welding quality between the connecting piece and the pin can also be improved. It avoids the phenomena of molten tin and de-welding of the weld seam in a high-temperature environment, greatly improves the service performance of the circuit board, and the weld seam is flat and smooth, without pores and crack defects, with good appearance. During welding, the welding stress and deformation are small, further improving the connection quality between the connecting piece and the pin. The setting of the elastic clamping part can quickly clamp the circuit board on the bracket, avoid the movement of the circuit board during the welding process, and improve the welding efficiency. On the other hand, when the circuit board is clamped into the elastic clamping part, the connecting piece fits on the pin. Therefore, there will be no gap between the connecting piece and the pin, further improving the quality of the weld seam. Moreover, the weld seam is set in different shapes according to actual needs to meet different welding requirements. Finally, a connection groove is provided on the side wall of the circuit board to facilitate the passing of the laser beam, so that the circuit board will not cause spatial interference to laser welding, realizing the quick welding and fixing of the connecting piece and the pin. On the other hand, it will not reduce the overall installation strength of the circuit board, and the connection groove is convenient to process and will not affect the installation and fixing of other components.

[0021] The length of the pin is L 0 , and the length of the connecting piece is L 1 , where: 1.9L 0 ≤ L 1 ≤2.1L 0 , and the cleaner in step one includes alcohol or / and a detergent. In this embodiment, the connecting piece is cut by a shearing machine or a saw, and the surface of the cut connecting piece should be free of burrs. Moreover, the connecting piece has a quadrilateral structure, and arc chamfers are provided at the four corners of the connecting piece, which can reduce the stress concentration and enhance the strength of the entire connecting piece. In addition, the length of the pin is L 0 , and the length of the connecting piece is L 1 , where: 1.9L 0 ≤ L 1 ≤2.1L 0 . On the one hand, it can increase the contact area between the pin and the connecting piece, improving the subsequent welding quality. On the other hand, it can increase the contact area between the connecting piece and the circuit board, improving the welding quality between the connecting piece and the circuit board. Finally, setting the cleaner as alcohol or / and a detergent can select the cleaner according to the specific material surface to meet different cleaning requirements. In this embodiment, the length L 1 of the connecting piece and the length of the pin being L 0 preferably adopt L 1 = 2L 0 , which can achieve the precise cutting of the connecting piece.

[0022] In step two, the connecting piece and the circuit board are subjected to wave soldering by a wave soldering machine, and the wave soldering includes the following steps: Step twenty: Place the wiped circuit board on the conveyor chain of the wave soldering machine, set the driving speed of the conveyor chain, and the driving speed of the conveyor chain is 1150 - 1250 mm / min; Step twenty - one: Evenly apply the soldering flux on the circuit board through a nozzle, and the specific gravity of the soldering flux is 0.8 - 0.82; Step twenty - two: Transfer the circuit board processed in step twenty - one to a preheating oven for preheating. The preheating temperature is 110 - 135°C. The preheating oven includes a first preheating zone, a second preheating zone, and a third preheating zone. The preheating temperature of the first preheating zone is 110 - 118°C, the preheating temperature of the second preheating zone is 119 - 128°C, and the preheating temperature of the third preheating zone is 129 - 135°C; Step twenty - three: Perform wave soldering on the circuit board preheated in step twenty - two, and the temperature of the wave soldering tank is 250 - 260°C; Step twenty - four: Cool the circuit board after wave soldering, and the cooling time is 12 - 15 min.

[0023] In this embodiment, the driving speed of the conveyor chain is 1200 mm / min, the specific gravity of the soldering flux is 0.8, the preheating temperature of the first preheating zone is 110°C, the preheating temperature of the second preheating zone is 120°C, the preheating temperature of the third preheating zone is 135°C, the temperature of the wave soldering tank is 258°C, and the cooling time is 15 min.

[0024] The wave soldering of the connecting piece and the circuit board by a wave soldering machine can simplify the soldering process of wave soldering and improve the soldering quality of wave soldering. Specifically, it includes the soldering processes of loading, flux coating, preheating treatment, wave soldering treatment, and cooling. The circuit board and the connecting piece are fixed through the loading step, and the transmission speed of the transmission chain is set to 1150 - 1250 mm / min, which can ensure the stable transmission of the circuit board and is conducive to the operation of subsequent processes. Secondly, the flux is evenly coated on the circuit board through a nozzle. In this embodiment, rosin flux is used as the flux. Rosin flux can maintain its activity within the soldering temperature, and there is no corrosion problem with the soldering slag. Through the coating of the flux, on the one hand, it can effectively reduce the surface tension of the circuit board, making the solder easier to wet and adhere to the soldering surface. On the other hand, it can ensure the cleanliness of the soldering surface to prevent bridging or false soldering during the soldering process. Setting the specific gravity of the flux to 0.8 - 0.82 can improve the soldering quality of wave soldering. When the specific gravity of the flux is less than 0.8, it cannot effectively protect the leads and circuits during preheating and soldering moments, resulting in reoxidation and thus affecting the soldering quality. When the specific gravity of the flux is greater than 0.8, it is easy to cause insufficient solder temperature and time, resulting in poor soldering. Then, the circuit board is transported to a preheating oven for preheating treatment, which can gradually raise the temperature of the circuit board and the connecting piece, reduce the temperature stress during soldering, and at the same time activate the activity of the flux. At the same time, the preheating oven is set with three preheating zones, and the preheating temperatures in the three preheating zones are structured to gradually increase. Specifically, the preheating temperature in the first preheating zone is 110 - 118 °C, the preheating temperature in the second preheating zone is 119 - 128 °C, and the preheating temperature in the third preheating zone is 129 - 135 °C. Different preheating schemes can be set according to actual preheating requirements to meet different production needs and greatly improve the preheating effect. Setting the temperature of the wave soldering tank to 250 - 260 °C can ensure the repeated melting and good wettability of the soldering points, and at the same time avoid overheating and oxidation caused by too high temperature, improving the quality of wave soldering. When the temperature of the wave soldering tank is less than 250 °C, the spreading rate and wetting performance of the solder become poor, which may lead to problems such as false soldering, tip pulling, and bridging. When the temperature of the wave soldering tank is greater than 260 °C, the connecting piece or the circuit board is prone to oxidation. Finally, the circuit board after wave soldering is cooled, which can achieve the curing treatment of the soldering points and ensure the strength and stability of the soldering points. In this embodiment, cooling is carried out by a fan.

[0025] The bracket 21 includes a left mounting bracket 211 and a right mounting bracket 212. Mounting holes 213 for installing battery cells are provided on both the left mounting bracket and the right mounting bracket. By setting the bracket as a structure of a left mounting bracket and a right mounting bracket, since mounting holes for installing battery cells are provided on both the left mounting bracket and the right mounting bracket, the installation process of the battery cell assembly is simplified, the installation quality of the battery cells can be improved, the shaking of the battery cells during the spot welding process can be avoided, and the welding quality of the nickel sheets can be improved. To improve the support strength of the bracket, a reinforcing rib is provided on both the left mounting bracket and the right mounting bracket in this embodiment. An upwardly protruding column is formed between the two reinforcing ribs. A through hole matching with the column is provided on the circuit board, which can achieve the accurate installation of the circuit board, avoid the reverse installation of the circuit board during installation, and ensure the fitting of the connecting piece and the pin. An elastic clamping member 23 is provided on both the left mounting bracket and the right mounting bracket. The horizontal axes of the two elastic clamping members are symmetrically arranged with respect to the horizontal axis of the bracket. During installation, the two elastic clamping members can be simultaneously opened outwards, which can also ensure the balanced force on the circuit board after installation and ensure the levelness of the circuit board installation. Specifically, the elastic clamping member 23 includes a locking block 231 and a spring piece 232. The locking block 231 is fixedly connected to the left mounting bracket and the right mounting bracket through the spring piece 232. An inclination angle 233 is provided on the locking block 231. By setting the elastic clamping member as a structure of a locking block and a spring piece, since an inclination angle is provided on the locking block, during installation, when the edge of the circuit board contacts the inclination angle, the locking block is opened outwards under the action of the spring piece. At this time, the circuit board can be installed on the bracket. When the connecting piece and the pin are fitted, the locking block is reset under the reset action of the spring piece. At this time, the upper end surface of the circuit board is subjected to the acting force of the locking block, and the circuit board cannot shake in the vertical direction. In addition, the setting of the inclination angle is beneficial to the installation positioning and disassembly and detachment of the locking block, reduces the acting force during installation positioning, and can achieve rapid installation.

[0026] The weld in step six is a linear weld. The width of the weld is 0.35 - 0.4 mm, and the depth of the weld is 0.12 - 0.15 mm. By setting the weld as a linear weld, the laser welding path is simplified, the operation of the operator is relatively easy, the technical difficulty is low, automated welding can be realized, the efficiency of laser welding can be improved, and the stability of the connection between the connecting piece and the pin can also be improved. Secondly, the linear weld can ensure the overall consistency and uniformity. In addition, by setting the width of the weld to 0.35 - 0.4 mm and the depth of the weld to 0.12 - 0.15 mm, the strength and stability of the weld can be ensured, and the problem of weld cracking can be avoided. If the width of the weld is less than 0.35 mm and the depth of the weld is less than 0.12 mm, the connection strength between the connecting piece and the pin cannot be guaranteed and the stress cannot be borne. If the width of the weld is greater than 0.4 mm and the depth of the weld is greater than 0.15 mm, it is easy to cause waste of materials and increase the working intensity of welding. In this embodiment, the width of the weld preferably adopts 0.36 mm, and the depth of the weld preferably adopts 0.13 mm.

[0027] The length of the connecting groove 101 is L 2 , where: 1.3L 0 ≤ L 2 ≤1.4L 0 , the width of the connecting groove is equal to the width of the connecting piece. The connecting groove can also be set in the structure of a strip hole. The setting of the connecting groove facilitates the passing of the laser beam, so that the circuit board will not form a spatial interference with the laser welding, realizing the rapid fixation of the connecting piece and the pin. On the other hand, it will not reduce the overall installation strength of the circuit board, and the connecting groove is convenient to process. Specifically, the length of the connecting groove is L 2 , where: 1.3L 0 ≤ L 2 ≤1.4L 0 , through the setting of the above structure, on the one hand, it can increase the width of the weld seam, the heat can be dissipated in time, and it will not affect the circuit board. Moreover, it can ensure the installation strength of the circuit board and will not form thermal deformation during welding. When L 2 <1.3L 0 , the heat cannot be dissipated. When L 2 >1.4L 0 , the installation strength of the circuit board is reduced, thereby reducing the service life of the circuit board. In addition, setting the width of the connecting groove equal to the width of the connecting piece can prevent the problem of gaps between the circuit board and the connecting piece and improve the welding quality of wave soldering. In this embodiment, the length of the connecting groove preferably adopts L 2 =1.35 L 0 .

[0028] The circuit board 10 is provided with a positioning groove 102 adapted to the connecting piece 11, which is beneficial to the accurate positioning and installation of the connecting piece on the circuit board, is beneficial to the wave soldering of the connecting piece and the circuit board, and will not appear the phenomenon of false soldering and desoldering. The connecting piece 11 is a copper-tin alloy connecting piece or a nickel-plated steel strip connecting piece or a nickel connecting piece, and the thickness of the connecting piece is equal to the thickness of the pin 31. The connecting piece can also be set as other alloy parts. In this embodiment, the thickness of the pin is 0.25 mm, and the copper-tin alloy connecting piece is preferably adopted for the connecting piece. Since the copper-tin alloy connecting piece has good electrical conductivity, corrosion resistance and mechanical strength, it can not only improve the welding quality between the pin and the connecting piece, provide reliable current transmission, but also enable it to maintain good performance in humid or corrosive environments. Secondly, setting the thickness of the connecting piece equal to the thickness of the pin is beneficial to the continuity of the weld seam, can improve the welding quality of the connecting piece and the pin, will not affect the speed of laser welding, can meet different welding temperatures, and in addition, the copper-tin alloy connecting piece is convenient for stamping forming.

[0029] A positioning structure 4 is provided between the bracket 21 and the circuit board 10. The positioning structure 4 includes a positioning post 41 and a positioning hole 42 which are connected to each other. The setting of the positioning structure can realize the positioning and installation of the circuit board. By setting the positioning structure as a structure of a positioning post and a positioning hole connected to each other, on the one hand, the positioning post and the positioning hole are convenient to process, reducing the error in the processing process and improving the positioning accuracy. On the other hand, the positioning post and the positioning hole make the installation and disassembly of the circuit board more convenient. Just align the positioning hole with the positioning post to achieve the installation of the circuit board, improving the installation efficiency of the circuit board. Specifically, the positioning post 41 is arranged on the bracket 21, and the positioning post 41 is arranged along the vertical direction or the horizontal direction. The positioning hole 42 is arranged on the circuit board 10, and an arc chamfer 43 is provided at the top end of the positioning post 41. Arranging the positioning post on the bracket and the positioning hole on the circuit board is beneficial to the installation and disassembly of the circuit board. Secondly, arranging the positioning post along the vertical direction or the horizontal direction can set the structure of the positioning post according to different installation requirements. In addition, in this embodiment, the installation structure of the positioning post and the bracket preferably adopts an integral structure, which can simplify the installation structure of the positioning post and the bracket and also improve the connection strength between the positioning post and the bracket. And a positioning post is provided on each of the left mounting bracket and the right mounting bracket, and the horizontal axes of the two positioning posts are symmetrically arranged about the horizontal axis of the bracket, enabling the circuit board to be balanced in force during installation and further improving the installation quality of the circuit board. Finally, the setting of the arc chamfer makes the edge of the top end of the positioning post smoother, facilitating the insertion of the positioning post into the positioning hole and also reducing the stress concentration at the top end of the positioning post, improving the service life of the positioning post.

[0030] In addition to the above preferred embodiments, the present invention has other implementation manners. Those skilled in the art can make various changes and deformations according to the present invention. As long as they do not depart from the spirit of the present invention, they shall fall within the scope defined by the appended claims of the present invention.

Claims

1. A method for assembling a battery assembly, comprising a circuit board assembly (1) and a battery cell assembly (2), wherein the battery cell assembly (2) comprises a bracket (21) and a plurality of battery cells (22) arranged in the bracket, wherein a nickel sheet (3) is provided on the battery cell, wherein a pin (31) is provided on the nickel sheet (3), and wherein a positioning frame (210) for mounting the pin is provided on the bracket, wherein: The circuit board assembly (1) comprises a circuit board (10) and a connecting piece (11) arranged at the bottom end of the circuit board, the bracket is provided with an elastic clamp (23), the connecting piece (11) and the pin (31) are fixedly connected by laser welding, and a connecting groove (101) is provided on the side wall of the circuit board (10). The battery assembly assembly method comprises the following steps in sequence: Step 1: Cut the length of the connecting piece according to the length of the pin, and use a cleaning agent to wipe the surface of the connecting piece, nickel sheet, pin and circuit board to remove surface oil, oxide layer and pollutants; Step 2: soldering the connection piece wiped in step 1 onto the circuit board by wave soldering to obtain a circuit board assembly; Step 3: Install multiple battery cells into the bracket to obtain a battery cell assembly, and the poles on the same side of the multiple battery cells are the same; Step 4: Install the nickel sheet wiped in step 1 onto the battery cell assembly obtained in step 3, and ensure that the bottom end of the pin fits on the positioning frame, and then spot weld the nickel sheet on the battery cell using a spot welder; Step 5: Install the circuit board assembly obtained in step 2 on the battery cell assembly welded in step 4, and fit the connecting piece onto the pin; Step 6: Use a laser to fix the connecting piece on the pin by laser welding to obtain a battery assembly.

2. A battery assembly assembly method according to claim 1, characterized in that: The length of the pin is L0, and the length of the connecting piece is L1, wherein: 1.9L0≤L1≤2.1L0, and the cleaning agent in step one includes alcohol and / or a detergent.

3. A battery assembly assembly method according to claim 2, characterized in that: The connecting piece and the circuit board in step 2 are subjected to wave soldering by a wave soldering machine, and the wave soldering includes the following steps: Step 20: Place the wiped circuit board on the conveyor chain of the wave soldering machine, and set the transmission speed of the conveyor chain to 1150-1250 mm / min; Step 21: Apply the soldering flux evenly on the circuit board through a nozzle, the specific gravity of the soldering flux is 0.8 to 0.82; Step 22: transferring the circuit board processed in step 21 to a preheating box for preheating treatment, the preheating temperature is 110-135°C, the preheating box includes a first preheating zone, a second preheating zone and a third preheating zone, and the preheating temperature of the first preheating zone is 110-118°C, the preheating temperature of the second preheating zone is 119-128°C, and the preheating temperature of the third preheating zone is 129-135°C; Step 23: subjecting the circuit board preheated in step 22 to wave soldering, with the temperature of the wave soldering tank being 250-260° C.; Step 24: Cool the circuit board after wave soldering for 12 to 15 minutes.

4. A battery assembly assembly method according to claim 1, characterized in that: In step 4, the temperature of the spot welding machine is 420-480° C., the spot welding current of the spot welding machine is 2.4-2.5KA, the pre-pressing time is 100-110ms, the spot welding time is 0.07-0.09ms, and the pressure holding time is 200-230ms.

5. A battery assembly assembly method according to claim 1, characterized in that: In step six, the laser's idle jump speed is 400-410 mm / s, the laser power is 60-70 W, the welding speed is 135-140 mm / s, the laser pulse frequency is 65-75 KHZ, the laser pulse duration is 0.45-0.55 μs, the weld is a linear weld, and the weld width is 0.35-0.4 mm, and the weld depth is 0.12-0.15 mm.

6. A battery assembly assembly method according to claim 2, characterized in that: The length of the connecting groove (101) is L2, wherein: 1.3L0≤L2≤1.4L0, and the width of the connecting groove is equal to the width of the connecting sheet.

7. A battery assembly assembly method according to claim 1, characterized in that: The circuit board (10) is provided with a positioning groove (102) adapted to the connecting piece (11), and the connecting piece (11) is a copper-tin alloy connecting piece or a nickel-plated steel strip connecting piece or a nickel connecting piece, and the thickness of the connecting piece is equal to the thickness of the pin.

8. A battery assembly assembly method according to claim 1, characterized in that: A positioning structure (4) is provided between the bracket (21) and the circuit board (10), and the positioning structure (4) comprises a positioning column (41) and a positioning hole (42) which are connected to each other.

9. A battery assembly assembly method according to claim 8, characterized in that: The positioning column (41) is arranged on the bracket (21), and the positioning column (41) is arranged in a vertical direction or a horizontal direction, the positioning hole (42) is arranged on the circuit board (10), and the top end of the positioning column (41) is provided with an arc chamfer (43).

10. A battery assembly assembly method according to claim 9, characterized in that: The bracket (21) comprises a left mounting frame (211) and a right mounting frame (212), the left mounting frame and the right mounting frame are both provided with mounting holes (213) for mounting electric cores, the left mounting frame and the right mounting frame are both provided with an elastic clamp (23), and the elastic clamp (23) comprises a locking block (231) and a spring sheet (232), the locking block (231) is fixedly connected to the left mounting frame (211) and the right mounting frame (212) via the spring sheet (232), and the locking block (231) is provided with an inclination angle (233).

Images