[0051] According to Figure 2~Figure 12 , A detailed description of the preferred embodiments of the present invention.
[0052] Such as Picture 11 As shown, the present invention provides a vehicle-use lithium-ion battery integrated module, including:
[0053] Several single battery modules, these single battery modules are arranged side by side, and are bonded with each other with structural glue to form an assembled plastic module;
[0054] The single battery module includes:
[0055] Thermally conductive frame 3 (made of thermally conductive plastic injection molding, base material is polyamide PA), such as image 3 with Figure 4 As shown, the thermally conductive frame 3 is a frame structure that can accommodate the single battery 1. The thermally conductive frame 3 has a hollow bottom plate 301 and a side plate 302 connected to the hollow bottom plate 301. The inner surface of the side plate 302 is in contact with the side surface of the single battery 1 Is coated with a layer of structural glue, and on the surface of the hollow bottom plate 301 that is in contact with the heat-conducting frame 3 in the adjacent single cell module, there is a glue groove 22, and the glue groove 22 is coated with structural glue;
[0056] The single battery 1, which is arranged in the heat conducting frame 3, such as figure 2 As shown, the single battery 1 has a rectangular hexahedral structure with front, back and side surfaces. The front or back of the single battery 1 is in contact with the inner surface of the hollow bottom plate 301 of the thermally conductive frame 3. A layer of thermally conductive silicone grease is coated on the surface contacting the inner surface of the hollow bottom plate 301;
[0057] Insulation cushion 5 (cut from Saint-Gobain K30-125 as the base material), such as Figure 5 As shown, it is pasted on the front or back of the single battery 1 and is arranged between the single battery 1 and the heat-conducting frame 3. The size of the insulating cushion 5 is larger than the hollow part on the hollow bottom plate 301 of the heat-conducting frame 3. The function of the insulating cushion 5 is to buffer the gap between the cells after the swelling of the single battery 1 becomes smaller, and to insulate the single battery 1;
[0058] Such as Picture 11 As shown, the integrated lithium-ion battery module for vehicles also includes:
[0059] A number of straps 15, which are tied to the assembly and shaping module, and the straps 15 are made of stainless steel;
[0060] A plurality of jumper pieces 17, each jumper piece 17 is welded to the poles of two adjacent single cells 1, and the jumper piece 17 is made of aluminum;
[0061] The wire harness 23, the sampling terminal 24 of each wire is connected to the copper terminal 21 of each sampling point of the assembled shaping module;
[0062] The upper cover 6 is fixed on the heat-conducting frame 3 with M4 tapping screws, and is used to insulate and protect the battery poles of the entire assembled and reshaped module.
[0063] The present invention also provides a method for integrating a lithium-ion battery integrated module for vehicles, which includes the following steps:
[0064] Step 1. Coat thermal grease on the single cell 1;
[0065] Such as figure 2 As shown, a layer of thermally conductive silicone grease is applied to the specified area 2 on the front or back of the single cell 1, and the shape and position of the specified area 2 are consistent with the front or back of the single cell 1 and the hollow bottom plate 301 of the thermally conductive frame 3. Match the surface contact area;
[0066] The thickness of the coated thermal grease is 0.1mm~0.2mm;
[0067] The uniformity of the thermal grease coating is achieved by screen printing. The thickness of the thermal grease is obtained by choosing different thicknesses of the screen screen, and the difference is obtained by selecting different meshes of the screen screen. The coating amount of thermal grease;
[0068] The thermal conductive silicone grease adopts insulating silicone grease;
[0069] Due to parts processing errors, it is impossible for the single battery 1 and the heat conducting frame 3 to fit perfectly. The gap between the single battery 1 and the heat conducting frame 3 is filled with air, and the thermal conductivity of air is only 0.02W/mK, which is much less than The thermal conductivity of the thermally conductive frame 3 is 14W/mK, which reduces the overall heat dissipation effect. The purpose of applying thermally conductive silicone grease is to remove air and reduce the thermal resistance between the single cell 1 and the thermally conductive frame 3. Picture 12 From the experimental data in, it can be seen that the relationship between temperature and time is linear. The linear formula is y=kx+b, where y is temperature (℃), x is time (s), and b is the starting temperature of the experiment. k is the slope, as can be seen from the figure, the slope k without thermal grease 1 =0.0059, the slope k when there is thermal grease 2 =0.0039, which shows that the temperature rise has been significantly slowed down after using thermal grease. Step 2. Coating structural adhesive on the inner surface of the side plate 302 of the thermally conductive frame 3;
[0070] Coat the structural adhesive uniformly on the side area 4 of the inner surface of the side plate 302 of the thermally conductive frame 3. The distance between the side area 4 and the edge of the side plate 302 of the thermally conductive frame 3 is 2~5mm, and the width of the side area 4 is the thermally conductive frame The width of the side plate 302 of 3 is 15-20%, which ensures that when the single battery 1 is installed in the thermally conductive frame 3, the structural glue can be distributed on the entire side of the single battery 1 to achieve the best bonding effect;
[0071] The structural adhesive has a certain curing time, which must be greater than the total production time of the entire production line, about 1 hour, to ensure that it cannot be cured before the subsequent process is completed, and the surface drying time of the structural adhesive is less than 20 minutes. The fluidity of structural adhesive is greater than 300pa.s, which improves the operability of the process;
[0072] Step 3. Assemble the single battery module (such as Figure 5 Shown);
[0073] Step 3.1. Paste the insulating cushion 5 with a single-sided adhesive (the model of the adhesive is 3M9495) on the side coated with thermally conductive silicone grease on the single cell 1, and the position where the insulating cushion 5 is pasted is the same as the thermal conductive frame 3. The hollow part on the hollow bottom plate 301 corresponds, so that after the assembly of the single battery module is completed, the insulating cushion 5 can completely cover the hollow part on the hollow bottom plate 301;
[0074] Step 3.2. Install the single battery 1 pasted with the insulating buffer pad 5 into the thermally conductive frame 3. The structural glue coated on the side area 4 of the inner surface of the side plate 302 of the thermally conductive frame 3 connects the side surface of the single battery 1 with The thermally conductive frames 3 are bonded together to form a single battery module;
[0075] Step 4. Apply structural glue (such as the glue slot 22) on the outer surface of the hollow bottom plate 301 of the heat-conducting frame 3 of each single battery module. Figure 4 Shown);
[0076] Use structural glue to replace the overall structure to provide the XYZ direction structural strength of the entire module;
[0077] The structural adhesive has a certain curing time, which must be greater than the total production time of the entire production line, about 1 hour, to ensure that it cannot be cured before the completion of the subsequent process, and the surface drying time of the structural adhesive is about 20 minutes. At the same time, the fluidity of the structural adhesive is greater than 300pa.s, which improves the operability of the process;
[0078] Step 5. Assemble and reshape several single battery modules;
[0079] Such as Image 6 As shown, a number of single battery modules are arranged on the fixture tray 11 on the shaping tool 8, and the screw pressing mechanism 9 is used to squeeze the two single battery modules from both ends to the middle, so that the adjacent single battery modules The battery modules are bonded to each other to form an assembled and reshaped module;
[0080] The fixture tray 11 can ensure the straightness of the single battery module during shaping;
[0081] The screw pressing mechanism 9 over-squeezes the size of the assembled shaping module by 0.2%. For example, when 36 single battery modules are bonded into an assembled shaping module, the total length of the assembled shaping module should be 515±0.5mm , After the screw rod pressing mechanism 9 performs 0.2% over-extrusion, the total length is 514±0.5mm; Step 6. Use a strap to tighten and assemble the shaping module;
[0082] Such as Figure 7 As shown, a steel belt tightening fixture 10 is used to tie a number of stainless steel straps 15 on the assembly and shaping module, and the stainless steel straps 15 are tightened;
[0083] The tightening force provided by the steel strap tightening jig 10 needs to be greater than 2000N. The strap 15 is forced to fit the R angle 22 at the corner of the assembly and shaping module by pulling force. The strap is completely tightened to achieve the purpose of restraining the module in the Y direction. Four straps The tightening force difference of belt 15 needs to be controlled within 10% to effectively prevent warping of the assembled plastic module;
[0084] Step 7. Weld the straps;
[0085] Such as Figure 8 As shown, in this embodiment, an 80W laser welding machine is used to perform laser spot welding on a strap 15 with a thickness of 0.5 mm and a width of 10 mm. The welding is carried out at four welding positions 14, and the distance between the welding position 14 and the edge of the strap 15 is 2~3mm, with a focal length of 225.5mm, a point pitch of 0.5mm, and a point diameter of 0.5mm, a group of 15 points are welded to form a welding track. The distance between two adjacent welding tracks that are not on the same line is 2~ 3mm, the distance between two welding tracks on the same straight line is 5~10mm;
[0086] When welding, it is necessary to ensure that there is no gap between the welding parts of the straps 15, and perform a tensile test after welding, and the welding strength is above 4000N and the yield strength of the 403 stainless steel belt material;
[0087] Step 8. Laser welding the jumper;
[0088] Use laser welding to weld the jumper 17 on the poles 16 of two adjacent single cells 1 to realize the series-parallel connection between the poles 16 of the single cells 1;
[0089] Step 8.1. Use laser spot welding to form a pre-welded spot to fix the jumper 17 on the jumper 17 and the pole 16 of the single cell 1 to prevent the weld 19 from becoming larger due to welding shrinkage;
[0090] Such as Picture 9 As shown, using an IPG2000 laser welding machine with a power of 1500W, the aluminum 3003 jumper 17 and the pole 16 are fixed by spot welding. There are 8 pre-welded joints 18 (the pre-welded joints must be at least 6). The two sides are symmetrical to prevent the one-sided weld seam from being too large due to welding shrinkage (when the weld seam exceeds 0.4, there is a 50% chance of failure);
[0091] Step 8.2. Use fiber laser welding to weld the weld seam 19, which requires inert gas protection, and use an exhaust gas recovery device to recover welding exhaust gas.
[0092] Use a laser welding machine with a power of 1400~1800W, a dual focus, and a speed of 80mm/s for continuous light welding. Since the welding track 20 formed by the welding spot 18 is polygonal, the welding track at the corner cannot be completely welded according to the shape of the weld. It causes energy accumulation, so the welding track 19 after continuous light welding needs to be smoothed, the welding process needs to be protected by inert gas, and the exhaust device is used to recover welding waste;
[0093] Step 9. Fix the sampling terminal 24 and the copper terminal 21 of the wiring harness 23 by soldering;
[0094] Such as Picture 10 As shown, the sampling terminal 24 of the wiring harness 23 is inserted into the copper terminal 21 of each sampling point, and the sampling terminal 24 and the copper terminal 21 of the wiring harness 23 are fixed by soldering to prevent loosening and complete the wiring harness connection.
[0095] Step 10: Install the upper cover 6 on the heat-conducting frame 3 through the self-tapping screws and the screw holes 26 of the heat-conducting frame 3.
[0096] The invention adopts battery unit assembly, and the connection between poles adopts aluminum jumper laser welding, which greatly improves the reliability and reduces the overall weight.
[0097] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.
