CN214956959U

CN214956959U - Lithium battery pole piece die forming and die casting device and die casting system

Info

Publication number: CN214956959U
Application number: CN202121579771.2U
Authority: CN
Inventors: 钱凤军; 吴波; 罗业富
Original assignee: Sichuan Wuliang Wisdom Road And Bridge Technology Co ltd
Current assignee: Sichuan Wuliang Wisdom Road And Bridge Technology Co ltd
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2021-11-30
Anticipated expiration: 2031-07-12

Abstract

The utility model provides a lithium battery pole piece mould shaping die-casting device and die-casting system, includes the base, is provided with bed die and pillar on the base, the bed die is used for packing into the mass flow body and lays the thick liquids of the mass flow body upper surface, installs fixed platform on the pillar, and the last drive arrangement that is provided with of fixed platform, drive arrangement are connected with the mould, and drive arrangement is used for the drive go up the mould extrusion and be located the thick liquids and the mass flow body of bed die. The utility model discloses a die-casting process has replaced adopting the roll-in process in the traditional production technology, go up the mould and continuously push down extrusion mass flow body, thick liquids, along with the pressure crescent of last mould, the compaction density of mass flow body increases gradually, unload the bounce-back can not appear of the back mass flow body at the external force, and the pressure that receives of each department of mass flow body is unanimous, the condition that each regional ductility is inconsistent also can not appear, the thickness of the battery pole piece that makes, compaction density can keep highly uniform, the processingquality, precision and the yield of battery pole piece have been improved remarkably.

Description

Lithium battery pole piece die forming and die casting device and die casting system

Technical Field

The utility model relates to a lithium battery pole piece processing field, concretely relates to lithium battery pole piece mould shaping die-casting device and die-casting system.

Background

With the development of lithium ion battery technology, the application range of lithium ion batteries is more and more extensive, and the lithium ion batteries are widely applied to the fields of electric vehicles, large-scale power supplies and energy storage besides portable electronic products. The lithium ion battery is popular with consumers due to the characteristics of high specific energy, high voltage, small self-discharge, environmental protection, good safety and the like.

The pole piece of the lithium battery is an important component of the lithium battery. The quality of the lithium battery can be seriously influenced by the defects of the pole piece of the lithium battery, and even potential safety hazards are generated. The manufacture of the battery pole piece belongs to the front-stage process of the lithium battery technology, and can be further divided into five processes of slurry preparation, slurry coating, pole piece rolling, pole piece slitting and pole piece drying. Patent CN112886068A discloses a method for manufacturing a lithium battery, which comprises the steps of preparing a negative electrode slurry or a positive electrode slurry, coating the negative electrode slurry or the positive electrode slurry on a copper foil or an aluminum foil, rolling, and cutting to obtain a negative electrode sheet or a positive electrode sheet.

However, in the conventional manufacturing process of the battery pole piece, the battery pole piece can rebound to a certain degree after being rolled, and the larger the rebound of the region with concentrated stress in the material region is, the problems of uneven thickness and inconsistent compaction density of the pole piece are caused; in addition, before rolling, in order to save the use amount of the active substance, the width of the coating is generally smaller than the width of the foil strip, namely, the edge of the foil strip is not covered with the active substance in a region with the width of several millimeters, so that the region which is not covered with the active substance during rolling is not contacted with a double roller of a rolling machine, so that secondary extension does not occur, and the copper foil and the aluminum foil have continuous extensibility, so that the extension degree of the region which is not attached with the active substance on the foil strip is different from that of the region which is large in the middle of the foil strip and is attached with the active substance, a wavy fold is formed at the edge of the foil strip, and the whole pole piece is easily scrapped in serious cases, and the yield is reduced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a lithium-ion battery pole piece mould shaping die-casting device to solve among the prior art lithium-ion battery pole piece production technology and adopt the pole piece that the roll-in process leads to bounce-back, the inconsistent problem of each regional ductility.

The above purpose is realized by the following technical scheme:

the utility model provides a lithium battery pole piece mould shaping die-casting device, includes the base, be provided with bed die and pillar on the base, the bed die is used for packing into the mass flow body and lays the thick liquids of the mass flow body upper surface in, install fixed platform on the pillar, the last drive arrangement that is provided with of fixed platform, drive arrangement is connected with the mould, drive arrangement is used for the drive go up the thick liquids and the mass flow body that the mould extrusion is located the bed die.

The die-casting device adopted by the technical scheme is used for completing a die-casting process so as to replace a rolling process in the traditional lithium battery pole piece process, and fundamentally avoids a series of problems such as pole piece rebound and the like caused by the rolling process.

Specifically, this die-casting device includes the base, the base is used for dismantling with equipment such as work platform, conveyer belt and is connected. The base is provided with a lower die and a pillar, wherein a fixed platform fixedly mounted on the pillar is used for carrying a driving device. In one or more embodiments, the driving device may be a hydraulic cylinder, and a piston rod of the hydraulic cylinder is controlled by a hydraulic oil pump to move in the vertical direction, so as to drive the upper mold directly or indirectly connected to the piston rod to move in the vertical direction. In one or more embodiments, the driving device may also be a motor, and preferably, the motor may be a stepping motor or a servo motor, and the screw rod is driven to rotate by the motor, so as to drive the upper mold directly or indirectly connected with the screw rod to move in the vertical direction.

The lower die is used for placing a current collector which is cut into a required specification, and slurry is poured above the current collector, so that the slurry is spread on the upper surface of the current collector. The upper die is pressed into the lower die under the driving of the driving device, and preset pressure is applied to the current collector and the slurry in the lower die, so that the battery pole piece is pressed to the required compaction density.

The die casting device needs to control the temperature during the die casting process. In some embodiments, the heating of the upper and lower dies of the die casting device is achieved by external means. For example, the upper and lower molds of the die casting device are located in the heating cavity, the driving device of the die casting device is located outside the heating cavity to prevent overheating, and the temperature of the heating cavity is controlled to raise the upper and lower molds to a specified drying temperature.

When the lithium battery pole piece forming device is used, after a current collector is placed in a lower die, anode slurry or cathode slurry is poured onto the upper surface of the current collector, the upper die and/or the lower die are heated through an external or internal heating device, heating is stopped after the temperature is raised to a drying temperature, the slurry and the current collector are actively cooled or naturally cooled, in the cooling process, a driving device drives the upper die to be pressed into the lower die, the pressure applied by the upper die is gradually increased, the compaction density of the current collector is gradually increased, pressing is stopped after the expected thickness is finally achieved, the upper die is lifted, and the formed lithium battery pole piece is taken out.

Through the die-casting device, the die-casting process is adopted to replace a rolling process adopted in the traditional production process, the upper die is continuously pressed and extruded with the current collector and the slurry, the compaction density of the current collector is gradually increased along with the gradual increase of the pressure of the upper die, the current collector does not rebound after the external force is removed, the pressure borne by each part of the current collector is consistent, and the condition that the ductility of each area is inconsistent does not occur, so the thickness and the compaction density of the battery pole piece prepared through the die-casting process can be kept highly consistent, and the processing quality, the precision and the yield of the battery pole piece are obviously improved; in addition, the die-casting device pours the slurry into the lower die, and can accurately control the amount of the slurry on each current collector, so that the compaction density and the thickness of each battery pole piece are ensured to be consistent under the condition of consistent die-casting conditions, and high-precision processing is realized.

Further, a controller is arranged on the fixing platform, the controller is electrically connected with the driving device, and the controller is used for adjusting the pressure applied to the slurry and the current collector by the upper die to reach the final pressure by controlling the driving device. The controller is used for sending an electric signal to the driving device, so that the driving device drives the upper die to move for a specified distance along the vertical direction, and then preset pressure is applied to the current collector and the slurry. In one or more embodiments, when the driving device is a hydraulic cylinder, the controller drives the hydraulic oil pump to push the piston rod to move up or down for a designated distance, and further drives the upper die to move for a designated distance, and during the process of pressing in the lower die and continuously moving down, the preset pressure is applied. In one or more embodiments, when the driving device is a motor, the controller drives the motor to rotate for a specified number of turns, drives the screw rod to rotate for a specified number of turns, further drives the upper die to move for a specified distance, and applies a preset pressure during pressing in the lower die and continuously moving downwards. Through the accurate control of the controller, the final pressure born by each battery pole piece between batches can be ensured to be completely consistent, and then the battery pole pieces with higher specification consistency can be produced.

Further, the controller is also used for adjusting the pressure applied to the slurry and the current collector by the upper die to at least one intermediate pressure by controlling the driving device, wherein the height of the upper die when the intermediate pressure is applied is higher than that of the upper die when the final pressure is applied; when the intermediate pressure or the final pressure is reached, the upper mold is kept at the current pressure for a certain period of time.

In the technical scheme, before the final pressure is reached, the controller can also adjust the pressure applied by the upper die to reach at least one intermediate pressure by controlling the driving device, and when the intermediate pressure is applied, the upper die does not move to the bottom end of the stroke of the upper die, so that the applied intermediate pressure or intermediate pressures are all smaller than the final pressure.

When the intermediate pressure or the final pressure is reached, the upper mold is kept at the current pressure for a certain period of time. The duration of the holding time can be set according to the current temperature, and can also be set according to whether the total duration is greater than the preset duration.

By keeping the corresponding pressure for a period of time, the method is not only beneficial to the uniform spreading of the slurry, but also beneficial to the drying of the slurry in the temperature reduction drying process, and simultaneously can further prevent the rebound of the pole piece, and finally achieves the required compaction density.

As a preferred embodiment of the present invention, the temperature rise of the die casting device is realized by controlling the self-heating device by the controller. Specifically, be provided with first heating device on the lower mould, be provided with second heating device on the last mould, the controller is through controlling first heating device with the temperature rise of lower mould to predetermined stoving temperature, through controlling second heating device with the temperature rise of last mould to predetermined stoving temperature.

In the technical scheme, heating devices are arranged in the upper die and the lower die, heating resistance wires are preferably adopted by the heating devices, and the heating devices are electrically connected with the controller and controlled to be turned on or turned off by the controller. In some embodiments, the controller may set a temperature rise time to raise the temperature of the upper and lower molds to a preset drying temperature within a certain time, so as to heat the slurry and the current collector in the lower mold to the drying temperature, and stop heating after the drying time is reached, and reduce the temperature of the die casting device by active cooling or natural cooling.

Further, a thermometer is arranged on the lower die and/or the upper die and used for monitoring the real-time temperature of the lower die and/or the upper die and sending an electric signal to the controller when the real-time temperature is lower than a threshold value, and the controller adjusts the pressure applied to the slurry and the current collector by the upper die according to the electric signal to reach the pressure corresponding to the threshold value. In the technical scheme, the holding time of the upper die at the intermediate pressure or the final pressure can be set by utilizing the real-time temperature of the die-casting device. Specifically, after entering the drying state, the drying rate is kept stable and a constant-speed drying state is presented. With the closing of the heating device, when the real-time temperature continuously drops to be lower than the threshold value, the thermometer immediately sends an electric signal to the controller, and the controller adjusts the position of the upper die according to the electric signal, so that the pressure applied by the upper die is adjusted to reach the pressure corresponding to the threshold value.

The principle of speed reduction drying is as follows: in the process of temperature reduction, the diffusion rate of the moisture in the slurry is smaller than the vaporization rate of the surface moisture at the wet bulb temperature in the early stage of temperature reduction, at the moment, the surface of the slurry cannot be maintained to be fully wet to form a dry area, and the drying rate is reduced compared with that in a constant-speed drying stage. With the further reduction of the temperature, the vaporization surface of the moisture gradually moves towards the interior of the material, so that the heat and mass transfer path is lengthened, the resistance is increased, and the drying rate is further reduced. Finally, when the upper die reaches the die-casting position, the slurry and the current collector which are subjected to speed reduction drying are extruded at higher pressure, and the combination strength of the slurry and the current collector is remarkably improved. In addition, the whole cooling process is combined with the characteristics of slurry, the speed reduction drying is adopted, the shrinkage phenomenon and the coating defect caused by sudden cooling at overhigh temperature are avoided, and in the cooling process, the temperature range of 90-150 ℃ is favorable for improving the adhesive force of PVDF (polyvinylidene fluoride), so that the final stripping strength value of the battery pole piece is the maximum.

As the utility model discloses well drive arrangement's preferred embodiment, drive arrangement includes the motor, the output of motor has lifting screw through reduction gear connection, threaded connection has the moving platform that can follow the pillar and remove on the lifting screw, moving platform's lower surface passes through the connecting rod and connects to supreme mould. In the technical scheme, the motor preferably adopts a stepping motor or a servo motor, and the fine adjustment of the number of rotation turns of the lifting screw rod is realized through the speed reducer, so that the accurate adjustment of the position of the upper die and the fine adjustment of the pressure applied to the upper die are realized. The lifting screw rod has the same function as the screw rod. The movable platform is provided with a through hole for the lifting screw to movably penetrate through, the inner wall of the through hole is in threaded fit with the lifting screw, and the movable platform is driven to move up and down relative to the fixed platform in the process of allowing the lifting screw to rotate; meanwhile, a guide hole or a guide cylinder is further arranged on the moving platform, and the inner diameter of the guide hole is matched with the support column, so that the moving platform and the upper die can stably move up and down along the support column. Through the setting, not only can realize going up the mould and steadily reciprocate along the pillar, avoid appearing the skew in the die-casting process, improve the stability and the security of device, the lifting screw has self-locking function moreover, can be at the in-process that steps up the pressure boost step by step, avoid battery pole piece to bounce-back to the compaction density and the thickness of accurate control pole piece are showing the quality and the yield that improve battery pole piece.

Another object of the utility model is to provide an adopted aforementioned any kind of lithium-ion battery pole piece mould shaping die-casting device's die-casting system, it drives a plurality of die-casting devices through the conveyer belt and removes, at the removal in-process, same platform die-casting device accomplishes the battery pole piece in proper order and packs into, thick liquids are poured into, the stoving of heaing up, cooling die-casting, the process that the battery pole piece took out, realize the uniformity of battery pole piece, the security, streamlined production, guaranteeing safety in production, under the prerequisite of improvement product quality, reduction in production cost, improve production efficiency.

The above purpose is realized by the following technical scheme:

a lithium battery pole piece die forming and die casting system comprises a conveyor belt and a driving wheel for driving the conveyor belt to move, wherein any one of a plurality of die casting devices is arranged on the conveyor belt, and in the process of moving along with the conveyor belt, each die casting device is sequentially switched to a charging state, a drying state, a pre-pressing state, a die casting state and a material taking state, or each die casting device is sequentially switched to the charging state, the drying state, the die casting state and the material taking state;

under the state of charge, the mass flow body of packing into in the bed die to pour thick liquids into on the mass flow body under the stoving state, go up mould, bed die and heat up to stoving temperature under pre-compaction state and the die-casting state, go up the mass flow body and the thick liquids in the mould under the mould extrusion under the material state, take out fashioned lithium-ion battery pole piece in the bed die.

In this technical scheme, current device can be adopted to drive wheel and conveyer belt, and under the drive of drive wheel, the conveyer belt moves continuously, and a plurality of die-casting devices on the conveyer belt move along with the conveyer belt synchronous motion. In the moving process, each die-casting device independently completes a charging state, a drying state, a die-casting state and a material taking state; or when the step-by-step pressurization is needed, each die-casting device independently completes the charging state, the drying state, the pre-pressing state, the die-casting state and the material taking state.

In operation, the current collector is put into a charging state, wherein the current collector which is cut into a required shape and size is put into an empty die, and slurry is poured on the upper surface of the current collector. After the charging is finished, the die-casting device enters a drying state, the temperature rise of the die-casting device is controlled in the continuous moving process until the upper die and the lower die are heated to the drying temperature, the slurry is dried at a constant speed at the drying temperature, the surface of the dried slurry is always kept with moist moisture for evaporation, and the die-casting device continuously moves in the whole drying state; when the temperature of the die-casting device is lower than a threshold value, the upper die moves downwards under the control of the controller, the pressure applied to the slurry and the current collector is increased, the pressurization in the speed reduction drying process is realized, and the final pressure in the die-casting state is finally reached; and after die casting is completed, taking out the lithium battery pole piece from the lower die. In another embodiment, a pre-pressing state may be added between the drying state and the die-casting state, wherein the pre-pressing state includes one or more intermediate pressures that facilitate uniform spreading of the slurry by maintaining the intermediate pressures for a period of time. This system is through combining the deceleration to dry and pressure boost gradually, and not only can avoid too high temperature to appear the shrink phenomenon after meeting cold suddenly, the coating defect appears, is favorable to the thick liquids evenly to expand moreover and dries with the thick liquids of deceleration stoving in-process, can also further prevent the pole piece bounce-back simultaneously, finally reaches required compaction density.

In some embodiments, the conveyor belt is an annular conveyor belt, so that after a lithium battery pole piece in the die casting device is taken out, the die casting device can be switched from a material taking state to a material charging state, that is, the current collector cut to the required specification can be placed into the lower die by using the mechanical arm again, and slurry is poured onto the current collector, thereby realizing rapid, efficient, cyclic and automatic production of the battery pole piece.

In some embodiments, the conveyor belt may be configured to be long enough to reduce the temperature of the die casting apparatus using natural cooling. As the preferred embodiment of the utility model, adopt the mode of initiative cooling, reduce the temperature of die-casting device. The system also comprises a cooling unit, wherein the cooling unit is used for reducing the temperature of the die-casting device, so that the cooling speed of the die-casting equipment is increased, the stroke and time of the die-casting device for completing a die-casting period are shortened, and the production efficiency is further improved.

Further, the setting position of the cooling unit is configured to reduce the temperature of the die-casting device in the drying state to a temperature required to switch to the pre-pressing state or the die-casting state; and/or the cooling unit is used for reducing the temperature of the die-casting device in the pre-pressing state to the temperature required for switching to the die-casting state.

Compared with the prior art, the utility model, following advantage and beneficial effect have:

1. the utility model discloses a die-casting process has replaced adopting the roll-in process in the traditional production technology, go up the mould and have lastingly pushed down the extrusion mass flow body, thick liquids, along with the pressure crescent of last mould, the compaction density of mass flow body increases gradually, the collection body can not appear rebounding after the external force is unloaded, and the pressure that receives everywhere of mass flow body is unanimous, the condition that each regional ductility is inconsistent can not appear yet, consequently, the thickness of the battery pole piece that makes through the die-casting process, compaction density can keep highly uniform, the processingquality, the precision and the yield of battery pole piece have been improved remarkably; in addition, the die-casting device pours the slurry into the lower die, and can accurately control the amount of the slurry on each current collector, so that the compaction density and the thickness of each battery pole piece are ensured to be consistent under the condition of consistent die-casting conditions, and high-precision processing is realized;

2. the utility model discloses an adopting the lifting screw to control lift platform and reciprocating, not only can realizing that the mould reciprocates along the pillar steadily, avoid appearing the skew in the die-casting process, improve the stability and the security of device, the lifting screw has self-locking function moreover, can be in the process of pressure boost step by step, avoid the battery pole piece to bounce back to the compaction density and the thickness of accurate control pole piece are showing and are improving the quality and the yield of battery pole piece;

3. the utility model not only is beneficial to the uniform expansion of the slurry, but also is beneficial to the drying of the slurry in the temperature reduction drying process by keeping the upper die position for a period of time when the intermediate pressure or the final pressure is reached, and simultaneously, the rebound of the pole piece can be further prevented, and the required compaction density is finally reached;

4. the die-casting system provided by the utility model adopts the conveyor belt to convey the die-casting device, and sequentially switches to a charging state, a drying state, a prepressing state, a die-casting state and a material taking state in the conveying process, so that the rapid, efficient, cyclic and automatic production of battery pole pieces can be realized;

5. the die-casting system provided by the utility model realizes the active cooling of the die-casting equipment by arranging the cooling unit, thereby accelerating the cooling speed of the die-casting equipment, shortening the stroke and time of the die-casting device for completing a die-casting period and further improving the production efficiency;

6. the utility model provides a die-casting system is through combining the deceleration to dry and pressure boost gradually, and not only can avoid too high temperature to appear the shrink phenomenon after meeting cold suddenly, the coating defect appears, is favorable to the thick liquids of thick liquids evenly to expand moreover and the drying of the thick liquids of deceleration stoving in-process, can also further prevent the pole piece bounce-back simultaneously, finally reaches required compaction density.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic structural view of a medium pressure casting apparatus according to an embodiment of the present invention;

fig. 2 is a schematic view of a lower mold of the die casting device according to an embodiment of the present invention, in which a current collector and slurry are filled;

fig. 3 is a schematic structural view of the die casting device in a drying state according to the embodiment of the present invention;

fig. 4 is a schematic structural view of the die-casting device in a pre-pressing state according to an embodiment of the present invention;

fig. 5 is a schematic structural view of the die-casting device in the die-casting state according to the embodiment of the present invention;

fig. 6 is a schematic view illustrating the separation of the upper and lower molds after the die casting device completes die casting according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a die-casting system according to an embodiment of the present invention;

fig. 8 is a schematic view of the die-casting device on the conveyor belt being switched from the drying state to the pre-pressing state or the die-casting state after being cooled.

Reference numbers and corresponding part names in the drawings:

1-base, 2-pillar, 3-lower mold, 31-first heating device, 4-upper mold, 41-second heating device, 5-fixed platform, 6-motor, 7-speed reducer, 8-lifting screw, 9-moving platform, 10-connecting rod, 11-controller, 12-current collector, 13-slurry, 21-conveyor belt, 22-driving wheel, 23-die casting device, and 24-cooling unit.

Detailed Description

To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.

In the description of the present invention, it should be understood that the terms "front", "back", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the scope of the present invention.

Example 1:

as shown in fig. 1-6 a lithium battery pole piece mould shaping die-casting device, including base 1, be provided with bed die 3 and pillar 2 on the base 1, bed die 3 is used for packing into mass flow body 12 and lays in the thick liquids 13 of mass flow body 12 upper surface, install fixed platform 5 on the pillar 2, be provided with drive arrangement on the fixed platform 5, drive arrangement is connected with mould 4, drive arrangement is used for the drive go up mould 4 extrusion and be located the thick liquids 13 and the mass flow body 12 of bed die 3.

In some embodiments, the heating of the upper and lower dies of the die casting device is achieved by external means. For example, the upper and lower molds of the die casting device are located in the heating cavity, the driving device of the die casting device is located outside the heating cavity to prevent overheating, and the temperature of the heating cavity is controlled to raise the upper and lower molds to a specified drying temperature.

In one or more embodiments, the obtained compaction density of the battery pole piece for the positive electrode is 3.2-3.6 g/cm³The obtained battery pole piece for the negative electrode has the compaction density of 1.3-1.6 g/cm³. Preferably, the compaction density of the positive battery pole piece is 3.5g/cm³The compacted density of the negative battery pole piece is 1.5g/cm³. The compaction density can affect the imbibition value, the internal resistance, the high-rate discharge performance and the median voltage, and the difference of the parameters can affect the high-rate cycle performance of the lithium ion battery, so that the compaction density has more complex influence on the high-rate cycle performance of the lithium ion battery。

Example 2:

on the basis of embodiment 1, as shown in fig. 1 to 6, a controller 11 is disposed on the fixed platform 5, the controller 11 is electrically connected to the driving device, and the controller 11 is configured to adjust the pressure applied by the upper mold 4 on the slurry 13 and the current collector 12 to a final pressure by controlling the driving device.

In some embodiments, the controller 11 is further configured to adjust the pressure applied by the upper mold 4 on the slurry 13 and the current collector 12 to at least one intermediate pressure by controlling the driving device, wherein the height of the upper mold 4 when the intermediate pressure is applied is higher than the height of the upper mold 4 when the final pressure is applied; when the intermediate pressure or the final pressure is reached, the upper mold 4 is kept at the current pressure for a while.

The controller is further capable of adjusting the pressure applied by the upper die to at least one intermediate pressure by controlling the drive means before the final pressure is reached, the upper die not yet having moved to the bottom end of its stroke while applying the intermediate pressure, such that the one or more intermediate pressures applied are each less than the final pressure. When the intermediate pressure or the final pressure is reached, the upper mold is kept at the current pressure for a certain period of time.

In this embodiment, the duration of the holding time is set according to whether the total duration is greater than the preset duration.

Specifically, the controller is electrically connected with a timing unit, the timing unit is used for starting to accumulate time and sending a stop signal to the controller when the pressure applied by the upper die reaches any intermediate pressure or final pressure, the controller controls the driving device to stop driving the upper die according to the stop signal, when the accumulated time is longer than a preset time, the timing unit is used for sending a start signal to the controller, and the controller controls the driving device to start driving the upper die according to the start signal. According to the technical scheme, a timing unit is arranged in or externally connected with the controller, timing is started when the timing unit sends a stop signal to the controller after any intermediate pressure or final pressure is reached, the controller controls the driving device to stop working after receiving the stop signal, and the upper die keeps the current pressure for a period of time. And when the time obtained by timing of the timing unit is longer than the preset time, stopping timing and sending a starting signal to the controller, and after receiving the starting signal, the controller controls the driving device to start working again to drive the upper die to continuously press down to reach the next intermediate pressure or the final pressure.

Example 3:

on the basis of the above-described embodiment, as shown in fig. 2 to 6, the temperature rise of the die-casting device is realized by controlling the self-heating device by the controller. Specifically, a first heating device 31 is disposed on the lower mold 3, a second heating device 41 is disposed on the upper mold 4, and the controller 11 raises the temperature of the lower mold 3 to a preset drying temperature by controlling the first heating device 31 and raises the temperature of the upper mold 4 to a preset drying temperature by controlling the second heating device 41.

In this embodiment, the controller can set up the heat-up time to the realization is with upper and lower mould intensification to predetermined stoving temperature in certain time, thereby heats thick liquids, the mass flow body in the lower mould to stoving temperature, and stops the heating after the stoving time reaches, reduces the temperature of die-casting device through initiative cooling or natural cooling.

In one or more embodiments, the drying temperature is 140 to 160 ℃, preferably 145 to 155 ℃, and more preferably 150 ℃. After the drying temperature is reached, the slurry in the lower die is heated to raise the temperature, the surface of the dried slurry is always kept with moist moisture for evaporation, the drying speed is kept stable at the moment and is in a constant-speed drying state, the drying temperature is set to be 140-160 ℃, crystallization of polyvinylidene fluoride (PVDF) serving as an adhesive in the slurry is facilitated, and the PVDF has high crystallinity in a temperature range, so that the PVDF has good binding power and has positive effects on internal resistance and cycle performance of a manufactured battery. In one or more embodiments, as shown in fig. 3, in the drying state, the lower surface of the upper mold is in contact with or very close to the upper surface of the slurry to dry the upper surface of the slurry using the high temperature of the upper mold, increasing the drying rate.

In some embodiments, the time for which the upper mold is held at the intermediate or final pressure is set using the real-time temperature of the die casting apparatus.

In this embodiment, a thermometer is disposed on the lower mold 3 and/or the upper mold 4, the thermometer is configured to monitor a real-time temperature of the lower mold 3 and/or the upper mold 4, and send an electrical signal to the controller 11 when the real-time temperature is lower than a threshold, and the controller 11 adjusts, according to the electrical signal, a pressure applied by the upper mold 4 to the slurry 13 and the current collector 12 to reach a pressure corresponding to the threshold.

In one or more embodiments, the lower die and the upper die are both provided with thermometers, after the drying state is finished, and after the temperature of the upper die and the lower die is reduced to be lower than a first threshold value, the controller controls the upper die to move downwards to a first position, and the upper die applies a first intermediate pressure at the first position; under the action of the first intermediate pressure, the upper die and the lower die continue to be cooled, when the real-time temperature is lower than a second threshold value, the controller controls the upper die to continue to move downwards to a final die-casting position, and the final pressure is applied to the upper die at the final die-casting position; and when the real-time temperature is lower than a third threshold value, the controller controls the upper die to lift up, and removes the pressure acting on the lithium battery pole piece. In one or more embodiments, a plurality of thresholds may be set, corresponding to a plurality of intermediate pressures, to achieve the effect of multi-stage gradual pressurization.

Example 4:

on the basis of the above embodiment, as shown in fig. 1 to 6, the driving device includes a motor 6, an output end of the motor 6 is connected with a lifting screw 8 through a speed reducer 7, the lifting screw 8 is in threaded connection with a moving platform 9 capable of moving along the pillar 2, and a lower surface of the moving platform 9 is connected to the upper die 4 through a connecting rod 10.

In this embodiment, the motor is preferably a stepping motor or a servo motor, and the fine adjustment of the number of turns of the lifting screw is realized through the speed reducer, so as to realize the accurate adjustment of the position of the upper die and the fine adjustment of the pressure applied to the upper die.

The lifting screw rod has the same function as the screw rod. The movable platform is provided with a through hole for the lifting screw to movably penetrate through, the inner wall of the through hole is in threaded fit with the lifting screw, and the movable platform is driven to move up and down relative to the fixed platform in the process of allowing the lifting screw to rotate; meanwhile, a guide hole or a guide cylinder is further arranged on the moving platform, and the inner diameter of the guide hole is matched with the support column, so that the moving platform and the upper die can stably move up and down along the support column. Through the setting, not only can realize going up the mould and steadily reciprocate along the pillar, avoid appearing the skew in the die-casting process, improve the stability and the security of device, the lifting screw has self-locking function moreover, can be at the in-process that steps up the pressure boost step by step, avoid battery pole piece to bounce-back to the compaction density and the thickness of accurate control pole piece are showing the quality and the yield that improve battery pole piece.

Example 5:

as shown in fig. 7 and 8, the lithium battery pole piece mold forming die-casting system includes a conveyor belt 21 and a driving wheel 22 for driving the conveyor belt 21 to move, wherein any one of the die-casting devices 23 provided in the foregoing embodiments is mounted on the conveyor belt 21, and in the process of moving along with the conveyor belt 21, each die-casting device 23 is sequentially switched to a charging state, a drying state, a pre-pressing state, a die-casting state and a material-taking state, or each die-casting device 23 is sequentially switched to a charging state, a drying state, a die-casting state and a material-taking state;

under the state of charge, current collector 12 is packed into in the bed die 3 to pour into thick liquids 13 on current collector 12 under the stoving state, go up mould 4, bed die 3 and heat up to drying temperature under pre-compaction state and the die-casting state, go up current collector 12 and thick liquids 13 in mould 3 under 4 extrudees of mould under the material state, take out fashioned lithium battery pole piece in the bed die 3.

In some embodiments, the conveyor belt may be configured to be long enough to reduce the temperature of the die casting apparatus using natural cooling.

In some embodiments, the temperature of the die casting device is reduced by actively reducing the temperature. Specifically, as shown in fig. 7 and 8, the system further includes a cooling unit 24, and the cooling unit 24 is configured to reduce the temperature of the die-casting device 23, so as to increase the cooling speed of the die-casting device, shorten the stroke and time of the die-casting device to complete one die-casting cycle, and further improve the production efficiency.

In one or more embodiments, the cooling unit may employ any of the existing cooling mechanisms, such as fans, air conditioning boxes, tunnel cooling systems, and the like.

Further, the setting position of the cooling unit 24 is configured to reduce the temperature of the die-casting device 23 in the drying state to a temperature required to switch to the pre-pressing state or the die-casting state; and/or the cooling unit is used to reduce the temperature of the die-casting device 23 in the pre-compression state to a temperature required for switching to the die-casting state.

Further, the conveyor belt 21 is an annular conveyor belt, and after the lithium battery pole pieces in the die-casting device 23 are taken out, the die-casting device 23 is switched from a material taking state to a material charging state. After the ring-shaped conveyor belt enables the lithium battery pole pieces in the die-casting device to be taken out, the die-casting device can be switched to a charging state from a material taking state, the current collector cut to the required specification can be placed into the lower die by the aid of the mechanical arm again, slurry is poured onto the current collector, and quick, efficient, circulating and automatic production of the battery pole pieces is achieved.

As used herein, "first," "second," etc. (e.g., first heating device, second heating device, etc.) are used only for clarity of description to distinguish between corresponding components, and are not intended to limit any order or to emphasize importance, etc. Further, the term "connected" used herein may be either directly connected or indirectly connected via other components without being particularly described.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a lithium battery pole piece mould shaping die-casting device, includes base (1), its characterized in that, be provided with bed die (3) and pillar (2) on base (1), bed die (3) are used for packing into mass flow body (12) and lay in thick liquids (13) of mass flow body (12) upper surface, install fixed platform (5) on pillar (2), be provided with drive arrangement on fixed platform (5), drive arrangement is connected with mould (4), drive arrangement is used for the drive go up thick liquids (13) and the mass flow body (12) that mould (4) extrusion is located bed die (3).

2. The lithium battery pole piece die forming and die casting device according to claim 1, wherein a controller (11) is disposed on the fixing platform (5), the controller (11) is electrically connected to a driving device, and the controller (11) is configured to adjust a pressure applied by the upper die (4) on the slurry (13) and the current collector (12) to a final pressure by controlling the driving device.

3. The lithium battery pole piece die forming and die casting device according to claim 2, wherein the controller (11) is further configured to adjust the pressure applied by the upper die (4) on the slurry (13) and the current collector (12) to at least one intermediate pressure by controlling the driving device, and the height of the upper die (4) when the intermediate pressure is applied is higher than the height of the upper die (4) when the final pressure is applied; when the intermediate pressure or the final pressure is reached, the upper mold (4) is kept at the current pressure for a period of time.

4. The lithium battery pole piece die forming and die casting device according to claim 2, wherein a first heating device (31) is disposed on the lower die (3), a second heating device (41) is disposed on the upper die (4), and the controller (11) controls the first heating device (31) to raise the temperature of the lower die (3) to a preset drying temperature and controls the second heating device (41) to raise the temperature of the upper die (4) to the preset drying temperature.

5. The lithium battery pole piece die forming and die casting device according to claim 4, wherein a thermometer is arranged on the lower die (3) and/or the upper die (4), the thermometer is used for monitoring the real-time temperature of the lower die (3) and/or the upper die (4) and sending an electric signal to the controller (11) when the real-time temperature is lower than a threshold value, and the controller (11) adjusts the pressure applied by the upper die (4) on the slurry (13) and the current collector (12) to reach the pressure corresponding to the threshold value according to the electric signal.

6. The lithium battery pole piece mold forming and die-casting device according to any one of claims 1 to 5, wherein the driving device comprises a motor (6), an output end of the motor (6) is connected with a lifting screw (8) through a reducer (7), the lifting screw (8) is in threaded connection with a moving platform (9) capable of moving along the pillar (2), and a lower surface of the moving platform (9) is connected to the upper mold (4) through a connecting rod (10).

7. A lithium battery pole piece mold forming and die-casting system is characterized by comprising a conveyor belt (21) and a driving wheel (22) for driving the conveyor belt (21) to move, wherein a plurality of die-casting devices (23) according to any one of claims 1 to 6 are mounted on the conveyor belt (21), and in the process of moving along with the conveyor belt (21), each die-casting device (23) is sequentially switched to a charging state, a drying state, a pre-pressing state, a die-casting state and a material taking state, or each die-casting device (23) is sequentially switched to the charging state, the drying state, the die-casting state and the material taking state;

under the state of charge, current collector (12) are packed into to bed die (3) to pour into thick liquids (13) on current collector (12) under the stoving state, go up mould (4), bed die (3) and heat up to drying temperature under pre-compaction state and the die-casting state, go up mass collector (12) and thick liquids (13) in mould (3) under mould (4) extrudes the bed die under the material state, take out fashioned lithium battery pole piece in bed die (3) under the material state.

8. The lithium battery pole piece die forming and die casting system according to claim 7, further comprising a cooling unit (24), wherein the cooling unit (24) is used for reducing the temperature of the die casting device (23).

9. The lithium battery pole piece die forming and die casting system according to claim 8, wherein the cooling unit (24) is configured to reduce the temperature of the die casting device (23) in the drying state to a temperature required for switching to the pre-pressing state or the die casting state; and/or the cooling unit is used for reducing the temperature of the die casting device (23) in the prepressing state to the temperature required for switching to the die casting state.

10. The lithium battery pole piece die forming and die casting system according to claim 7, wherein the conveyor belt (21) is an endless conveyor belt, and after the lithium battery pole piece in the die casting device (23) is taken out, the die casting device (23) is switched from a taking state to a charging state.