A method for processing a battery pole piece with less burrs

Abstract

The present application relates to a kind of battery pole piece's little burr processing method, battery pole piece's little burr processing method includes cutting battery pole piece with the cutting speed greater than 160 m / s, and before cutting and during cutting, liquid nitrogen is poured to the cutting area of battery pole piece, so that cutting area is in brittle state during cutting.It has beneficial effect, it provides a kind of tool unit relative to the cutting speed of battery pole piece greater than 160 m / s ultra-high speed machining technology combining liquid nitrogen cooling battery pole piece to improve the hard brittleness of battery pole piece in cutting process, to reduce the generation of burr.Maximizes to reduce the generation of burr in battery pole piece processing process, does not need secondary processing to remove burr, improves the processing efficiency of battery pole piece is lower, and will reduce processing cost, and not introduce cutting fluid, more environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery pole piece processing, and particularly relates to a battery pole piece less burr processing method and a processing device. BACKGROUND

[0002] As an important component of a battery, the quality of a battery pole piece directly affects the performance and reliability of the battery. However, the traditional battery pole piece material is mainly copper or aluminum. These metal materials are relatively soft and have good plasticity. Under the action of shear stress in the processing process, plastic deformation is generated, which can easily lead to the generation of a large number of burrs, which directly restricts the performance and service life of the battery. In the use process, serious burr residues can pierce the diaphragm and cause short circuit of the battery, thereby causing explosion.

[0003] Therefore, how to effectively reduce the burrs generated on the battery pole piece in the processing process has become an urgent problem to be solved. The traditional solutions include mechanical deburring, chemical deburring, electrolytic deburring and the like. The above methods need to remove the burrs through secondary processing after the battery pole piece is processed, which leads to low processing efficiency of the battery pole piece, high cost, and problems such as environmental pollution caused by the introduction of chemical substances. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present application provides a battery pole piece less burr processing method and a processing device, which solves the technical problem of low processing efficiency of the traditional method for removing burrs on the battery pole piece.

[0006] (II) Technical solutions

[0007] In order to achieve the above-mentioned purposes, the main technical solutions adopted by the present application include:

[0008] In a first aspect, the present application provides a battery pole piece less burr processing method:

[0009] cutting the battery pole piece at a cutting speed greater than 160 m / s, and pouring liquid nitrogen to a cutting area of the battery pole piece before and during the cutting, so that the cutting area is in a brittle state during the cutting.

[0010] According to the present application, the battery pole piece clamped on the workpiece base is cut by the tool unit;

[0011] the rotating speed of the tool unit is 0-60000 rpm; or,

[0012] the rotating speed of the tool unit is 0-60000 rpm, and the rotating speed of the battery pole piece is 0-10000 rpm.

[0013] The injection flow rate of the liquid nitrogen is 0.1-0.6 L / min.

[0014] The particle size of the cutter unit is 60-400 mesh.

[0015] According to the present application, the cutting speed is calculated by the formula:

[0016]

[0017] wherein, is the average strain rate of the battery pole piece in a brittle state, is the cutting speed, is the feed speed of the cutter unit for cutting the battery pole piece, is the machining depth of the battery pole piece, is the rotary diameter of the cutter unit;

[0018] is 3.12×10 5 s -1 -5.67×10 5 s -1 ;

[0019] is 300 m / s-500 m / s;

[0020] is 100 mm / min-1000 mm / min;

[0021] is 10 -6 m-2×10 -5 m;

[0022] is 0.06 m-0.12 m.

[0023] According to the present application, the average strain rate of the battery pole piece in a brittle state is calculated by the formula:

[0024]

[0025] wherein, is the difference between the yield strength and the ultimate tensile strength of the battery pole piece, is the material constant of the battery pole piece, is the sensitivity coefficient of the strain rate of the battery pole piece to the embrittlement of the battery pole piece;

[0026] 30.4-62.7Mpa;

[0027] 1.458-1.532.

[0028] In a second aspect, the present application further provides a battery pole piece burr processing device for a battery pole piece burr processing method, comprising a workpiece unit, a tool unit and a liquid nitrogen nozzle.

[0029] The workpiece unit comprises a workpiece base; the workpiece base can clamp the battery pole piece, and the cut zone of the battery pole piece protrudes from the peripheral wall of the workpiece base.

[0030] The tool unit comprises a tool driving mechanism and a tool; the driving shaft of the tool driving mechanism is fixedly connected with the tool, and the tool driving mechanism drives the tool to rotate; the rotation axis of the tool is parallel to the central axis of the workpiece base, the tool can cut the cut zone of the battery pole piece, and the tool cuts the battery pole piece at a cutting speed greater than 160 m / s.

[0031] The liquid nitrogen nozzle is located between the tool and the workpiece base, and is used for pouring liquid nitrogen to the cut zone of the battery pole piece.

[0032] According to the present application, a rack, a first three-axis mechanical arm and a second three-axis mechanical arm are further included.

[0033] The workpiece base, the first three-axis mechanical arm and the second three-axis mechanical arm are all fixed on the rack.

[0034] The first three-axis mechanical arm is fixedly connected with the main body of the tool driving mechanism, and the second three-axis mechanical arm is fixedly connected with the liquid nitrogen nozzle.

[0035] According to the present application, the liquid nitrogen nozzle is communicated with a liquid nitrogen bottle through a connecting pipe, and the liquid nitrogen bottle is used for injecting liquid nitrogen into the liquid nitrogen nozzle.

[0036] The injection flow rate of the liquid nitrogen is 0.1-0.6 L / min.

[0037] According to the present application, the tool unit rotates, and the workpiece base is static; or,

[0038] The tool unit is static, and the workpiece base rotates; or,

[0039] The tool unit and the workpiece unit rotate in opposite directions.

[0040] The rotation speed of the driving shaft of the tool driving mechanism is 0-60000 rpm.

[0041] The diameter of the tool is 110-120mm.

[0042] According to the application, the tool unit is stationary, the workpiece base rotates, or the tool unit and the workpiece unit rotate reversely, and the workpiece unit further comprises a workpiece driving mechanism.

[0043] The driving shaft of the workpiece driving mechanism is fixedly connected with the workpiece base, the workpiece driving mechanism drives the workpiece base to rotate, and the workpiece base drives the battery pole piece to rotate synchronously.

[0044] The rotating speed of the workpiece base is 0-10000rpm.

[0045] The diameter of the workpiece base is 60-300mm.

[0046] According to the application, the top of the workpiece base is fixedly provided with clamps, and the clamps can clamp the battery pole piece.

[0047] The clamps are provided in multiple numbers, and the multiple clamps are arranged at intervals along the circumference of the workpiece base.

[0048] The clamps comprise first clamping plates and second clamping plates arranged at intervals along the height direction of the workpiece base.

[0049] The battery pole piece is clamped between the first clamping plates and the second clamping plates, and the first clamping plates and the second clamping plates are detachably fixed on the workpiece base by fasteners.

[0050] (Three) beneficial effects

[0051] The beneficial effects of the application are that in the battery pole piece burr processing method and processing device, the cutting speed of the tool unit relative to the battery pole piece is greater than 160m / s, the super-speed processing technology is combined with the method of cooling the battery pole piece by liquid nitrogen to improve the hard brittleness of the battery pole piece in the cutting process, so as to reduce the generation of burrs.

[0052] Adopting the super high cutting speed greater than 160 m / s, the strain rate of the battery pole piece increases in the cutting process, the cutting heat is reduced, the deformation behavior of the battery pole piece is converted from plastic deformation to brittle fracture, so that the battery pole piece is more prone to brittle removal, which helps to reduce the generation of burrs. At the same time, pouring -196 ℃ liquid nitrogen cooling to the cutting area of the battery pole piece in the cutting process can reduce the temperature of the battery pole piece and effectively reduce the heat generated in the cutting process, so as to improve the dislocation nucleation potential barrier of the battery pole piece, hinder the dislocation movement, make the battery pole piece more hard and brittle, and further reduce the formation of burrs in the machining process. The generation of burrs in the machining process of the battery pole piece is minimized, the burrs do not need to be removed by secondary machining, the machining efficiency of the battery pole piece is improved, the machining cost is reduced, and the cutting fluid is not introduced, which is more environmentally friendly. Moreover, the super high speed machining is an advanced manufacturing technology, compared with the traditional machining method, the super high speed machining has the advantages of high machining efficiency, small tool wear, no need to introduce cutting fluid, clean and environmentally friendly and the like. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a perspective view of the battery pole piece little burr machining device of the application;

[0054] Figure 2 It is a top view of the battery pole piece little burr machining device of the application; Figure 1

[0055] Figure 3 It is a clamp of the battery pole piece little burr machining device of the application; Figure 2

[0056] Figure 4 It is a front view of the battery pole piece little burr machining device of the application; Figure 3

[0057] Figure 5 It is an exploded view of the battery pole piece little burr machining device of the application; Figure 2

[0058] Figure 6 It is a schematic view of the change of the minimum stress required for dislocation to overcome the potential barrier at different temperatures.

[0059]

BRIEF DESCRIPTION OF DRAWINGS

[0060] 1: tool unit; 11: tool driving mechanism; 12: cutter head; 13: tool;

[0061] 2: workpiece unit; 21: workpiece base; 22: clamp; 221: first clamping plate; 222: second clamping plate; 223: fastener; 23: workpiece driving mechanism;

[0062] 3: battery pole piece 3;

[0063] 4: liquid nitrogen nozzle;

[0064] f: feed direction of the tool.​​​​ DETAILED DESCRIPTION

[0065] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0066] Example 1

[0067] See also Figures 1-5 The present invention proposes a method for processing battery pole pieces with low burrs. The method involves cutting the battery pole piece 3 at a cutting speed exceeding 160 m / s, and pouring liquid nitrogen into the cut area of ​​the battery pole piece 3 before and during cutting, thereby rendering the cut area brittle during the cutting process. This method combines ultra-high-speed machining at a cutting speed exceeding 160 m / s with liquid nitrogen cooling of the battery pole piece 3 to improve the hardness and brittleness of the battery pole piece 3 during cutting, thereby reducing burrs, improving the battery's lifespan and reliability, and reducing the risk of explosion during battery use.

[0068] It should be noted that liquid nitrogen is poured before cutting to cool the battery pole piece 3 in advance, and liquid nitrogen is continuously poured during the cutting process to ensure that the battery pole piece 3 is fully cooled.

[0069] By using an ultra-high cutting speed greater than 160 m / s, the strain rate of the battery electrode 3 increases during the cutting process, while cutting heat generation decreases. The deformation behavior of the battery electrode 3 changes from plastic deformation to brittle fracture, making the battery electrode 3 more susceptible to brittle removal and helping to reduce the generation of burrs. At the same time, pouring liquid nitrogen at -196°C into the cut area of ​​the battery electrode 3 during the cutting process can lower the temperature of the battery electrode 3 and effectively reduce the heat generated during the cutting process, thereby increasing the structural dislocation nucleation barrier of the battery electrode 3, hindering dislocation movement, making the battery electrode 3 more hard and brittle, and further reducing the formation of burrs during the processing. The generation of burrs during the processing of the battery electrode 3 is minimized, eliminating the need for secondary processing to remove burrs, and improving the processing efficiency of the battery electrode 3. Moreover, as an advanced manufacturing technology, ultra-high-speed processing has the advantages of high processing efficiency, low tool wear, no need for cutting fluid, and clean and environmentally friendly compared to traditional processing methods.

[0070] Further, the reason for the burr generated in the battery pole piece 3 during processing is that the battery pole piece 3 is plastically deformed, resulting in burrs at the cutting edge of the battery pole piece 3. Therefore, the burr-reducing processing method of the battery pole piece of the present application converts the battery pole piece 3 from plasticity to brittleness to reduce the generation of burrs during cutting. The key to plastic-brittle conversion is whether the dislocation in the microstructure of the material can reach the tip of the crack in time to blunt the crack. If the dislocation can nucleate and move to the tip of the crack to blunt the crack in time, the battery pole piece 3 will exhibit plasticity. Conversely, if the dislocation cannot reach the tip of the crack in time, the crack will expand, and the battery pole piece 3 will exhibit brittleness. Therefore, reducing the dislocation motion speed is conducive to the plastic-brittle conversion of the battery pole piece 3.

[0071] The dislocation motion speed mainly depends on the time required for the thermal activation of the dislocation to cross the barrier and the dislocation slip time, as shown in the following formula:

[0072]

[0073] wherein, is the dislocation motion speed, is the time required for the thermal activation of the dislocation to cross the barrier, is the dislocation slip time.

[0074] According to the above formula, increasing the time required for the thermal activation of the dislocation to cross the barrier and the dislocation slip time can reduce the dislocation motion speed .

[0075] The burr-reducing processing method of the battery pole piece of the present application reduces the dislocation motion speed by increasing the time required for the thermal activation of the dislocation to cross the barrier and the dislocation slip time , thereby suppressing dislocation motion to achieve plastic-brittle conversion of the battery pole piece 3 and reduce the generation of burrs during processing of the battery pole piece 3.

[0076] The key factors affecting the time required for the thermal activation of the dislocation to cross the barrier and the dislocation slip time of the material are the plastic strain rate of the material:

[0077] The internal defects of the battery pole piece 3 are activated under impact load in the processing process, causing the nucleation of micro-cracks. If the battery pole piece 3 is in a low strain rate condition, the dislocation has enough time to overcome the thermal activation barrier to reach the crack tip, which plays a role in passivating the crack, and the battery pole piece 3 will deform plastically. When the strain rate of the battery pole piece 3 is high enough, the dislocation does not have enough time to overcome the barrier, the crack will expand, and the accumulation of dislocations will also dislocation movement, thereby causing more cracks in the material, realizing the plastic-brittle transition of the battery pole piece 3.

[0078] Therefore, increasing the strain rate of the material, using the strain rate hardening effect in the processing process, can achieve the embrittlement of the material, so that the battery pole piece 3 is converted from plastic deformation to brittle removal, reducing the generation of burrs. Further, in mechanical processing, the calculation formula of the plastic strain rate of the material is:

[0079]

[0080] Among them, is the strain rate of the material, is the rake angle of the tool, is the shear angle, is the cutting speed, is the material chip thickness.

[0081] From the above formula, under the premise that other conditions are consistent, increasing the cutting speed can effectively increase the strain rate of the material, so that the material tends to undergo plastic-brittle transition. Therefore, the battery pole piece 3 is cut at a cutting speed of more than 160 m / s in the present application, so that the battery pole piece 3 tends to be converted to brittle.

[0082] Different materials have corresponding plastic-brittle transition speeds. For the battery pole piece 3 such as aluminum and copper, which belong to face-centered cubic packing materials, at present, it is generally believed that it is difficult to achieve the desired embrittlement effect by simply increasing the processing speed of the battery pole piece 3 due to its many slip systems. Therefore, other processing conditions need to be combined to improve the embrittlement degree of the battery pole piece 3, that is, liquid nitrogen is poured into the cut area of the battery pole piece 3 to reduce the temperature of the battery pole piece 3:

[0083] In the processing process, the temperature is closely related to the dislocation movement. The dislocation thermal activation formula is:

[0084]

[0085] Among them, is the activation energy of the dislocation overcoming the barrier, is the energy required for the dislocation to overcome the barrier at zero temperature, is the minimum stress required for the material to deform plastically at zero temperature, The minimum stress required for plastic deformation of a flow stress material, p and q are dimensionless parameters, i.e. constants, which can be derived from empirical formulae based on the relevant parameters of different materials.

[0086] The minimum stress required for dislocation to overcome the barrier to motion as a function of temperature is fitted from the thermal activation of dislocations, see Figure 6 F is the minimum stress required for dislocation to overcome the barrier to motion at different temperatures T. As the temperature decreases, the stress required for dislocation to overcome the barrier also increases, leading to the accumulation of dislocations. The larger the stacking fault energy of the battery tab 3 at lower temperatures, on the other hand, also indicates that the barrier that dislocations need to overcome will increase. This indicates that a decrease in temperature is more conducive to the brittle transition of the material.

[0087] At the same time, in terms of dislocation slip, as the temperature decreases, the lattice structure of the battery tab 3 is more compact, atomic vibration decreases, intermolecular slip resistance increases, and dislocation motion is hindered. The dislocation motion decreases at low temperature, and the required processing speed strain rate for brittle transition decreases accordingly, so that the same conditions can achieve more obvious material brittle effect. It also shows that a decrease in temperature is more conducive to the brittle transition of the material, and the required cutting speed to achieve the same degree of brittleness is relatively low, which is more conducive to implementation.

[0088] Furthermore, due to the large amount of cutting heat generated during the cutting process of the battery tab 3, the temperature rises, leading to an increase in the plasticity of the material, which is not conducive to the brittle transition of the battery tab 3. Pouring liquid nitrogen into the cut area of the battery tab 3 can also absorb cutting heat to reduce temperature, which can help the battery tab 3 to achieve brittle removal.

[0089] As can be seen from the above, the battery tab deburring method can improve the hard brittleness of the battery tab 3 by combining high-speed cutting with liquid nitrogen cooling to reduce the generation of burrs. Due to the high cutting speed, the strain rate of the battery tab 3 increases during processing, the cutting heat is reduced, and the deformation behavior of the material changes from plastic deformation to brittle fracture, making it easier for the battery tab 3 to appear brittle removal, which helps to reduce the generation of burrs. At the same time, liquid nitrogen cooling is applied during cutting to reduce the temperature of the battery tab 3 and reduce the heat generated during cutting, which can improve the dislocation nucleation barrier of the battery tab 3, hinder dislocation motion, and make the battery tab 3 more hard and brittle, further reducing the formation of burrs during processing. Reducing the temperature of the battery tab 3 can also reduce the cutting speed required for plastic brittle transition, so that the battery tab 3 deburring method is easier to implement.

[0090] Further, the battery tab 33 clamped on the workpiece base 21 is cut by the tool unit 1.

[0091] ​When the battery pole piece 3 is stationary and the cutter unit 1 rotates so that the cutter unit 1 cuts the battery pole piece 3, the rotation speed of the cutter unit 1 is 0-60000 rpm, thereby achieving a higher cutting speed; or,

[0092] When the cutter unit 1 is stationary and the battery pole piece 3 rotates so that the cutter unit 1 cuts the battery pole piece 3, the rotation speed of the battery pole piece 3 is 0-10000 rpm, thereby achieving a higher cutting speed; or,

[0093] When the battery pole piece 3 and the cutter unit 1 rotate in opposite directions so that the cutter unit 1 cuts the battery pole piece 3, the rotation speed of the cutter unit 1 is 0-60000 rpm and the rotation speed of the battery pole piece 3 is 0-10000 rpm, thereby achieving a higher cutting speed.

[0094] Preferably, the battery pole piece 3 and the cutter unit 1 rotate in opposite directions so as to reach the cutting speed required for the plastic-brittle transition of the battery pole piece 3.

[0095] Preferably, the particle size of the cutter unit 1 is 60-400 mesh.

[0096] The particle size refers to the size of the particles in the cutter unit 1 that are used for the main machining of the workpiece. The smaller the particle size of the cutter unit 1, the smaller the amount of workpiece material removed in a single cutting, and the greater the strain rate, which is more conducive to the plastic-brittle transition. The use of the cutter unit 1 with the above-mentioned preferred particle size is more conducive to the plastic-brittle transition of the battery pole piece 3 under the same conditions.

[0097] Further, the injection flow rate of liquid nitrogen is 0.1-0.6 L / min. Preferably, the injection flow rate of liquid nitrogen is 0.5 L / min. Too little liquid nitrogen can lead to insufficient cooling of the battery pole piece 3, and too much liquid nitrogen can cause waste, and the machine tool is also prone to failure and damage in a low-temperature environment.

[0098] Further, the cutting speed is calculated according to the formula:

[0099]

[0100] wherein, is the average strain rate of the battery pole piece 3 in the brittle state, is the cutting speed, is the feed speed of the cutter unit 1, is the machining depth of the battery pole piece 3, is the rotation diameter of the cutter unit 1.

[0101] Preferably, is 3.12x10 5 s -1 -5.67x10 5 s-1 , is 100 mm / min-1000 mm / min, is 10 - 6 m-2x10 -5 m, is 0.06 m-0.12 m.

[0102] The cutting speed is obtained by bringing the above-mentioned preferred parameters into the calculation formula of the cutting speed is 300 m / s-500 m / s, and the cutting speed is used to cut the battery pole piece 3, and the battery pole piece 3 is cooled by liquid nitrogen, which is more conducive to the plastic-brittle transition of the battery pole piece 3 in the cutting process under the same conditions, brittle cutting is realized, and burr generation is reduced.

[0103] Specifically, when the battery pole piece 3 is stationary and the tool unit 1 rotates, the cutting speed is the rotation speed of the tool.

[0104] When the tool unit 1 is stationary and the battery pole piece 3 rotates, the cutting speed is the rotation speed of the battery pole piece 3.

[0105] When the battery pole piece 3 and the tool unit 1 rotate in opposite directions, the cutting speed is the sum of the rotation speeds of the tool 13 and the battery pole piece 3.

[0106] Preferably, the battery pole piece 3 and the tool unit 1 rotate in opposite directions so as to achieve the super-high cutting speed required for the plastic-brittle deformation of the battery pole piece 3.

[0107] Specifically, the average strain rate of the battery pole piece 3 in the brittle state is calculated by the following formula:

[0108]

[0109] wherein, is the difference between the yield strength and the ultimate tensile strength of the battery pole piece 3, is the material constant of the battery pole piece 3, is the sensitivity coefficient of the strain rate of the battery pole piece 3 to the embrittlement of the battery pole piece 3.

[0110] Preferably, is 30.4-62.7 Mpa, is 1.458-1.532. The above-mentioned preferred parameters are brought into the calculation formula of the average strain rate to obtain the preferred , and then brought into the calculation formula of cutting speed to obtain the preferred cutting speed .

[0111] It should be noted that the corresponding , , and of the battery pole piece 3 of different materials are different, and the setting of each parameter needs to be adjusted according to the difference of the material to realize the brittle cutting of the battery pole piece 3.

[0112] More specifically, for the ductile-brittle transition of the material, it is generally believed that when the yield strength of the material reaches the ultimate tensile strength , the material becomes brittle, and the difference between the two is .

[0113] For the battery pole piece 3, taking 7075 T6 aluminum alloy as an example, the difference at room temperature is 57.2 MPa, at liquid nitrogen cooling temperature-196℃ is 33.4 MPa, is 14.3, is 1.5.

[0114] The calculated strain rate required for the ductile-brittle transition of the battery pole piece 3 of 7075 T6 aluminum alloy material at liquid nitrogen cooling temperature is 3.28×10 5 s -1 .

[0115] Embodiment 2

[0116] The embodiment further provides a little burr processing device of battery pole piece based on the embodiment 1.

[0117] The little burr processing device comprises a workpiece unit 2, a tool unit 1 and a liquid nitrogen nozzle 4.

[0118] The workpiece unit 2 comprises a workpiece base 21. The workpiece base 21 can clamp the battery pole piece 3 to make the battery pole piece 3 stationary and high-precision positioning relative to the workpiece base 21. The cut zone of the battery pole piece 3 protrudes from the peripheral wall of the workpiece base 21.

[0119] The tool unit 1 comprises a tool driving mechanism 11 and a tool 13. The driving shaft of the tool driving mechanism 11 is fixedly connected with the tool 13, and the tool driving mechanism 11 drives the tool 13 to rotate. The rotation axis of the tool 13 is parallel to the central axis of the workpiece base 21, the tool 13 can cut the cut zone of the battery pole piece 3, and the tool 13 cuts the battery pole piece 3 at a cutting speed greater than 160 m / s.

[0120] A liquid nitrogen nozzle 4 is located between the tool 13 and the workpiece base 21, for pouring liquid nitrogen to the machined area of the battery pole piece 3.

[0121] Further, the tool unit 1 further comprises a tool disc 12. The driving shaft of the tool driving mechanism 11 is fixedly connected to the tool disc 12, and the tool blade is fixedly connected to the tool 13. The tool driving mechanism 11 drives the tool 13 to rotate through the tool disc 12.

[0122] Specifically, the rotating speed of the driving shaft of the tool driving mechanism 11 is 0-60000 rpm, so as to provide a higher cutting speed and achieve the cutting speed required for the brittle transition of the battery pole piece 3.

[0123] Specifically, the tool driving mechanism 11 is an electric motor.

[0124] Specifically, the diameter of the tool 13 is 110-120 mm. The tool with this parameter can combine the average strain rate and the setting of each parameter in the calculation formula of the cutting speed to make the cutting speed obtained more conducive to brittle cutting of the battery pole piece 3. If the diameter of the tool 13 is less than 110 mm, it is not conducive to achieve a higher cutting speed. If the diameter of the tool 13 is greater than 120 mm, the centrifugal force is too large at a higher cutting speed, and the tool is prone to burst.

[0125] Preferably, the diameter of the tool 13 is 118 mm.

[0126] Further, the tool unit 1 rotates, and the workpiece base 21 is stationary; or,

[0127] the tool unit 1 is stationary, and the workpiece base 21 rotates; or,

[0128] the tool unit 1 and the workpiece unit 2 rotate in opposite directions.

[0129] Preferably, the tool unit 1 and the workpiece unit 2 rotate in opposite directions, and the sum of the rotating speeds of the tool unit 1 and the workpiece unit 2 is the cutting speed , so as to achieve the ultra-high cutting speed required for the brittle transition of the battery pole piece 3.

[0130] Further, when the tool unit 1 is stationary and the workpiece base 21 rotates, or when the tool unit 1 and the workpiece unit 2 rotate in opposite directions, the workpiece unit 2 further comprises a workpiece driving mechanism 23.

[0131] The driving shaft of the workpiece driving mechanism 23 is fixedly connected to the workpiece base 21. The workpiece driving mechanism 23 drives the workpiece base 21 to rotate, and the workpiece base 21 drives the battery pole piece 3 to rotate synchronously.

[0132] Specifically, the workpiece driving mechanism 23 is an electric motor.

[0133] Specifically, the rotating speed of the workpiece base 21 is 0-10000 rpm to provide a higher cutting speed.

[0134] Further, the top of the workpiece base 21 is fixedly provided with a clamp 22, which can clamp the battery tab 3.

[0135] Preferably, a plurality of clamps 22 are provided, which are arranged at intervals along the circumference of the workpiece base 21 to clamp a plurality of battery tabs 3 on the same workpiece base 21, so that a plurality of battery tabs 3 can be machined at one time to improve the machining efficiency.

[0136] Specifically, the clamp 22 includes a first clamping plate 221 and a second clamping plate 222 arranged at intervals along the height direction of the workpiece base 21; or the clamp 22 is a height-adjustable clamp based on piezoelectric ceramics to facilitate clamping battery workpieces of different thicknesses.

[0137] The battery tab 3 is clamped between the first clamping plate 221 and the second clamping plate 222, and the first clamping plate 221 and the second clamping plate 222 are detachably fixed on the workpiece base 21 by adhesion, adsorption or fasteners 223. Clamping the battery tab 3 by the first clamping plate and the second clamping plate can be suitable for clamping battery tabs 3 of different thicknesses and is convenient to disassemble. Preferably, the first clamping plate 221 and the second clamping plate 222 are detachably fixed on the workpiece base 21 by fasteners 223 to facilitate disassembly.

[0138] Specifically, the fastener 223 is a screw to facilitate disassembly.

[0139] Specifically, the diameter of the workpiece base 21 is 60-300 mm. Using a workpiece base 21 with a diameter less than 60 mm is not conducive to clamping a plurality of battery tabs 3 at the same time, and the linear speed of the battery tab 3 will also be affected. While using a workpiece base 21 with a diameter greater than 300 mm is prone to chatter during high-speed rotation, affecting the machining precision.

[0140] Preferably, the diameter of the workpiece base 21 is 190 mm to facilitate clamping a plurality of battery tabs 3 at the same time.

[0141] Preferably, the workpiece base 21 is further provided with a pressure sensor for monitoring the force exerted by the tool 13 on the battery tab 3.

[0142] Further, it further comprises a rack, a first three-axis mechanical arm and a second three-axis mechanical arm;

[0143] The workpiece base 21, the first three-axis mechanical arm and the second three-axis mechanical arm are all fixed on the rack;

[0144] The first three-axis mechanical arm is fixedly connected with the tool driving mechanism 11. The first three-axis mechanical arm can drive the tool 13 to move along the X, Y and Z directions through the tool driving mechanism 11, so that the tool 13 can move at a certain feed speed in the X, Y and Z directions, so as to realize that the tool 13 and the battery pole piece 3 are in contact at a specific position and cut the battery pole piece 3. The second three-axis mechanical arm is fixedly connected with the liquid nitrogen nozzle 4. The liquid nitrogen nozzle 4 is driven by the second three-axis mechanical arm to move along the X, Y and Z directions, so as to move the liquid nitrogen nozzle 4 to a position corresponding to the tool 13 and the clamp 22, and pour liquid nitrogen to the cut area of the battery pole piece 3, so that the liquid nitrogen can fully enter the cut area and accurately cool the cut area.

[0145] Further, the liquid nitrogen nozzle 4 is connected with the liquid nitrogen bottle through the connecting pipe. The liquid nitrogen bottle is used to inject liquid nitrogen into the liquid nitrogen nozzle 4.

[0146] Specifically, the liquid nitrogen nozzle 4 is connected with the liquid nitrogen bottle through the connecting pipe. A valve body is arranged on the connecting pipe. The opening of the liquid nitrogen bottle is controlled by the valve body to control the discharge flow of the liquid nitrogen, so that the liquid nitrogen can be uniformly poured on the cut area of the battery pole piece 3.

[0147] Preferably, the injection flow of the liquid nitrogen is 0.4-0.6L / min. More preferably, the injection flow of the liquid nitrogen is 0.5L / min. When the liquid nitrogen is too little, it is easy to cause insufficient cooling of the battery pole piece 3. Too much will cause waste, and the machine tool is also easy to be damaged in a low-temperature environment.

[0148] It should be noted that the little burr processing device can be applied to three-axis machining systems such as lathes and grinding machines, so that the battery pole piece 3 can adapt to different machining requirements and improve the universality.

[0149] Further, the operation method of the little burr processing method of the battery pole piece is as follows:

[0150] S1, first, set the battery pole piece 3 to be processed and the little burr processing device for processing the battery pole piece 3;

[0151] S2, before processing the battery pole piece 3, the tool unit 1, the workpiece unit 2 and the liquid nitrogen nozzle 4 are positioned, so that the little burr processing device processes the cut area of the battery pole piece 3 at a preset processing depth, so as to ensure the processing speed, accuracy and sufficient cooling of the cut area by the liquid nitrogen.

[0152] S3, the tool unit 1 and the workpiece unit 2 move at a preset cutting speed to process the battery pole piece 3. The preset cutting speed not less than the processing speed corresponding to the material embrittlement of the battery pole piece 3. It should be pointed out that the material embrittlement of the battery pole piece 3 is related to the processing temperature of the battery pole piece 3, the processing load applied by the processing unit, the processing depth, the cutting speed and the performance of the battery pole piece 3, etc. The cutting speed corresponding to the material embrittlement speed of the battery pole piece 3 can be calculated by fixing other parameters and the formula and cutting .

[0153] S4, judging whether the battery pole piece 3 is embrittled by the chip formed after the battery pole piece 3 is cut: judging by observing the chip morphology, fracture morphology and other characteristics of the battery pole piece 3 under different cutting speeds (different strain rates). In general, the chip of plastic material removal is continuous and strip-shaped, while the chip of brittle material is broken. With the gradual increase of the processing speed, the plastic material will be embrittled, and the chip will change from continuous strip-shaped to jagged or broken. Taking TC4 titanium alloy as an example, the titanium alloy is a plastic material, but with the increase of the cutting speed, the chip changes from continuous chip to jagged chip, the brittle fracture of the workpiece surface increases, and the ductile fracture decreases, indicating that the material is embrittled. Therefore, when the chip of the battery pole piece 3 is jagged, it means that the battery pole piece 3 is embrittled.

[0154] S5, according to the specific processing requirement, setting the parameters such as single processing depth, speed, liquid nitrogen flow, etc., and finally realizing the processing of the battery pole piece 3. According to the properties of different materials used in the battery pole piece 3 and the specific processing depth requirement (different plastic-brittle transition cutting speed), the deburring processing device can set different processing parameters each time. In addition, a smaller granularity cutter 13 can be selected to process the battery pole piece 3. The granularity refers to the size of the particles in the cutter 13 used for the main processing of the workpiece. The smaller the granularity of the cutter 13, the smaller the removal amount of the workpiece material in single cutting, the greater the strain rate, and the more conducive to the plastic-brittle transition.

[0155] S6, after the processing is completed, the chip is collected and the surface of the battery pole piece 3 is observed to verify whether the battery pole piece 3 is embrittled, and finally realize the deburring processing.

[0156] In the present application, unless otherwise clearly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0157] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature, can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "over", "above" and "on top of" the second feature, can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "under", "below" and "underneath" the second feature, can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0158] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0159] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can modify, modify, replace and modify the above-described embodiments within the scope of the present application.

Claims

1. A method of burr reduction processing of a battery electrode sheet, characterized by, The battery pole piece (3) is cut by the burr-reducing machining device at a cutting speed greater than 160 m / s, and the burr-reducing machining device pours liquid nitrogen to the cut area of the battery pole piece (3) before and during cutting, so that the cut area is in a brittle state during cutting. The cutting speed The calculation formula is: ； wherein is the average strain rate of the battery pole piece (3) in the brittle state, is the cutting speed, is the feed speed of the tool unit (1) for cutting the battery pole piece (3), is the machining depth of the battery pole piece (3), is the rotational diameter of the tool unit (1); is 3.12 x 10 5 s -1 -5.67 x 10 5 s -1 ; is 300 m / s - 500 m / s; is 100 mm / min - 1000 mm / min; 10 -6 m-2 x 10 -5 m; is 0.06m - 0.12m.

2. The burr-reducing machining method of the battery pole piece according to claim 1, wherein The battery pole piece (3) clamped on the workpiece base (21) is cut by the tool unit (1); The rotation speed of the tool unit (1) is 0-60000 rpm; or The rotation speed of the tool unit (1) is 0-60000 rpm, and the rotation speed of the battery pole piece (3) is 0-10000 rpm; The injection flow rate of the liquid nitrogen is 0.1-0.6 L / min; The granularity of the tool unit (1) is 60-400 mesh.

3. The burr-reducing processing method for battery pole pieces according to claim 1, characterized in that: average strain rate of the battery electrode sheet (3) in a brittle state The calculation formula is: ； wherein the difference between the yield strength and the ultimate tensile strength of the battery electrode sheet (3), a material constant of the battery electrode sheet (3), a sensitivity coefficient of the strain rate of the battery electrode sheet (3) to embrittlement of the battery electrode sheet (3); is 30.4-62.7 MPa; is 1.458-1.

532.

4. A burr-reducing processing method for the battery electrode sheet according to any one of claims 1 to 3, characterized by, The burr-reducing machining device comprises a workpiece unit (2), a tool unit (1), and a liquid nitrogen nozzle (4); The workpiece unit (2) comprises a workpiece base (21); the workpiece base (21) can clamp the battery pole piece (3), and the cut area of the battery pole piece (3) protrudes from the peripheral wall of the workpiece base (21); The tool unit (1) comprises a tool driving mechanism (11) and a tool (13); the driving shaft of the tool driving mechanism (11) is fixedly connected to the tool (13), and the tool driving mechanism (11) drives the tool (13) to rotate; the rotation axis of the tool (13) is parallel to the central axis of the workpiece base (21), the tool (13) can cut the cut area of the battery pole piece (3), and the tool (13) cuts the battery pole piece (3) at a cutting speed greater than 160 m / s; The liquid nitrogen nozzle (4) is located between the tool (13) and the workpiece base (21) and is used to pour liquid nitrogen to the cut area of the battery pole piece (3).

5. The burr-reducing processing method of a battery electrode sheet (3) according to claim 4, characterized by, The burr-reducing machining device further comprises a rack, a first three-axis mechanical arm, and a second three-axis mechanical arm; The workpiece base (21), the first three-axis mechanical arm, and the second three-axis mechanical arm are all fixed on the rack; The first three-axis mechanical arm is fixedly connected to the main body of the tool driving mechanism (11), and the second three-axis mechanical arm is fixedly connected to the liquid nitrogen nozzle (4).

6. The method of burr reduction of a battery electrode sheet according to claim 4, wherein The liquid nitrogen nozzle (4) is connected to a liquid nitrogen bottle through a connecting pipe, and the liquid nitrogen bottle is used to inject liquid nitrogen into the liquid nitrogen nozzle (4); The injection flow rate of the liquid nitrogen is 0.1-0.6 L / min.

7. The burr-reducing machining method of the battery pole piece according to claim 4, wherein The tool unit (1) rotates, and the workpiece base (21) is stationary; or The tool unit (1) is stationary, and the workpiece base (21) rotates; or The tool unit (1) and the workpiece unit (2) rotate in opposite directions; The rotation speed of the driving shaft of the tool driving mechanism (11) is 0-60000 rpm; The diameter of the tool (13) is 110-120 mm.

8. The burr-reducing processing method for a battery pole piece according to claim 7, characterized in that: The tool unit (1) is stationary, the workpiece base (21) rotates, or the tool unit (1) and the workpiece unit (2) rotate reversely, and the workpiece unit (2) further comprises a workpiece driving mechanism (23); The driving shaft of the workpiece driving mechanism (23) is fixedly connected with the workpiece base (21), the workpiece driving mechanism (23) drives the workpiece base (21) to rotate, and the workpiece base (21) drives the battery pole piece (3) to rotate synchronously; The rotating speed of the workpiece base (21) is 0-10000rpm; The diameter of the workpiece base (21) is 60-300mm.

9. The burr-reducing processing method for a battery pole piece according to claim 4, characterized in that: The top of the workpiece base (21) is fixedly provided with clamps (22), and the clamps (22) can clamp the battery pole piece (3); The number of the clamps (22) is multiple, and the multiple clamps (22) are arranged at intervals along the circumference of the workpiece base (21); The clamps (22) comprise first clamping plates (221) and second clamping plates (222) arranged at intervals along the height direction of the workpiece base (21); The battery pole piece (3) is clamped between the first clamping plates (221) and the second clamping plates (222), and the first clamping plates (221) and the second clamping plates (222) are detachably fixed on the workpiece base (21) by fasteners (223).

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