CN-122025848-A - Oversized cylindrical sodium ion battery structure and safety cooperative system

CN122025848ACN 122025848 ACN122025848 ACN 122025848ACN-122025848-A

Abstract

The invention discloses an oversized cylindrical sodium ion battery structure and a safety cooperative system, and relates to the technical field of sodium ion battery structure and safety control, comprising a double-gradient self-adaptive current collecting disc, wherein the spoke center is wide, the edge is narrow, the distance is cooperative gradient, and a base material is an aluminum-based composite layer covered with a nano titanium coating; the four-function integrated core rod is internally provided with a diversion channel and a gradient through hole, is coated with a temperature-sensitive conductive coating, is filled with porous ceramic particles and is provided with a pressure release sheet, is of a positive-negative electrode-diaphragm bidirectional adaptive structure, is provided with composite coatings on two sides of a diaphragm pore in a gradient distribution manner, is coated with heat sealing glue on the edges, is provided with a grading pressure release-fire extinguishing cooperative safety system, is provided with an electrolyte-material cooperative optimization system, and is soaked by adopting high-salt concentration electrolyte and multicomponent additives through a multi-step liquid injection process. The invention solves the problems of uneven current collection, slow electrolyte infiltration, delayed safety response and the like of the traditional battery through full-chain innovation, improves the production efficiency by the process, adapts to multiple application scenes and meets the requirement of large-scale mass production.

Inventors

Ma Faxing
ZHANG QUANYING
LI HUIYAN

Assignees

钠悦新能源(上海)有限公司

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (10)

1. The ultra-large cylindrical sodium ion battery structure and the safety cooperative system are characterized by comprising the following modules: The double-gradient self-adaptive current collecting disc adopts spoke design with wide center and narrow edge, the base material is an aluminum-based composite layer and is covered with a nano titanium coating, and the middle part of the spoke is provided with a micro notch to complete the adaptation of the current collecting efficiency and the structural strength; The four-function integrated core rod is made of modified PP, a regular hexagon hollow channel is arranged in the modified PP and filled with porous alumina ceramic particles, a spiral diversion trench is arranged on the inner wall of the channel, a gradient micro-through hole is formed in the side wall of the channel, a temperature-sensitive conductive coating is coated on the outer layer, and a temperature-sensitive pressure release sheet is arranged in the middle of the modified PP and has the functions of diversion, temperature control, pressure release and conductivity; the positive electrode, the negative electrode and the diaphragm are in a bidirectional adaptation structure, the diaphragm adopts a PP base layer and non-woven fabric functional layer composite structure, the porosity is distributed in a gradient manner, different functional coatings are respectively coated on the positive electrode side and the negative electrode side, and the edge of the diaphragm is wider than the pole piece and is coated with heat sealing glue; The system comprises a grading pressure relief and fire extinguishing cooperative safety system, a pre-pressure relief, a main pressure relief and fire extinguishing three-level protection, wherein the pre-pressure relief is triggered by a temperature sensitive pressure relief sheet, the main pressure relief is realized through an end cover double annular notch, a temperature sensor is arranged at the same time, and the fire extinguishing system passes through a fire extinguishing material in a core rod channel; the electrolyte and material synergistic optimization system adopts electrolyte with specific proportion and functional additives, and adopts the vacuum liquid injection and secondary liquid injection processes.
2. The oversized cylindrical sodium ion battery structure and safety cooperative system according to claim 1, further comprising a current distribution uniformity optimization module for quantifying current distribution difference through cooperative design of spoke width and distance, wherein the calculation is performed by cooperative proportioning of spoke size parameters, and current collection uniformity is completed by matching different current density requirements of an anode and a cathode.
3. The ultra-large cylindrical sodium ion battery structure and the safe cooperative system according to claim 1 are characterized by further comprising a multi-parameter cooperative gradient coating process adaptation module, wherein the positive electrode coating is formed by arranging 3 groups of high-precision spray heads along the width direction, the feeding quantity is in gradient distribution, the adaptation coating speed and the wet film thickness are set in cooperation with ultrasonic vibration, the laser thickness meter is arranged at an outlet for feeding back and adjusting the height of the spray heads in real time, the negative electrode coating station is provided with a vacuum cover, the corresponding wet film thickness is set by adopting low-frequency ultrasonic assistance, the positive electrode compaction is in a gradient pressure mode, the negative electrode compaction is in constant low pressure, and finally the adapted positive electrode compaction density and the negative electrode compaction density are respectively achieved.
4. The ultra-large cylindrical sodium ion battery structure and safety cooperative system according to claim 1, further comprising a low-temperature composite welding and impedance closed loop module, wherein the welding process adopts a spot welding fixing, roll welding conduction and inertia protection combined process, the laser spot welding adopts fiber laser, the welding temperature is controlled to form uniform welding spots, the ultrasonic roll welding is set to adapt to ultrasonic frequency and roll welding pressure, the welding temperature rise is controlled, the welding station is filled with high-purity argon for inertia protection, the four-probe impedance tester is used for point-by-point detection after welding, the ultrasonic roll welding power is automatically increased for secondary welding when the impedance does not reach the standard, and finally the stress is eliminated through cold pressing.
5. The oversized cylindrical sodium ion battery structure and safety cooperative system according to claim 1, further comprising an electrolyte infiltration efficiency improving module, wherein the mandrel flow guiding structure and the diaphragm pore gradient design are combined, and the calculation accelerates diffusion of electrolyte in the anode and the cathode through cooperation of structural parameters and technological parameters.
6. The ultra-large cylindrical sodium ion battery structure and safety cooperative system as claimed in claim 1, further comprising a vacuum, pressure and water cooperative sealing module, wherein a three-stage sealing structure is adopted, a one-stage seal is arranged between the pole sleeve and the end cover, and an additive nano-meter is arranged The modified fluororubber sealing ring comprises a second-stage sealing, a third-stage sealing liquid injection, a vacuum pressure-maintaining and pressurizing process, wherein the outer side of the sealing ring is coated with an aluminum foil and polytetrafluoroethylene composite film, metal sealing is completed through laser welding, a liquid injection station is arranged on a line Karl Fischer moisture meter for real-time monitoring, the vacuum pressure-maintaining time is automatically prolonged when moisture is not up to standard, and a sealing nail is matched with a pole liquid injection hole to complete ventilation and flow guide.
7. The oversized cylindrical sodium ion battery structure and the safe cooperative system according to claim 1, further comprising a conical contact current collecting disc optimizing module, wherein the current collecting disc is provided with a conical contact area and an annular conductive area, the conical contact area is used for improving the contact area, the annular conductive area is subjected to silver plating treatment, the edge of the current collecting disc is provided with a silicon steel elastic buckle which is clamped and fixed with the edge of the tab, and the current collecting disc is provided with an annular diversion groove which is cooperated with a mandrel diversion channel to accelerate electrolyte to diffuse to the tab area.
8. The ultra-large cylindrical sodium ion battery structure and safety cooperative system according to claim 1, further comprising a process, material, structure and performance closed-loop control module, wherein pulping and coating parameters are linked, the viscosity change of positive electrode slurry is correspondingly adjusted to the coating speed, baking and formation parameters are linked, formation initial current is set according to residual moisture, multi-link online monitoring is set, material agglomeration rate and dispersion uniformity after pulping, post-winding lug flatness, residual moisture after baking and SEI film thickness deviation after formation are respectively detected, and subsequent parameters are automatically adjusted when any link does not reach the standard.
9. The ultra-large cylindrical sodium ion battery structure and the safety cooperative system according to claim 1 are characterized by further comprising a temperature-sensitive conductive coating self-adaptive adjusting module, wherein the temperature-sensitive conductive coating on the outer layer of the mandrel is composed of carbon nanotubes and polyvinylidene fluoride, the conductivity of the coating is improved when the temperature is increased, the local heat of the anode can be rapidly exported, the sodium ion migration is assisted by depending on a carbon nanotube conductive network in a low-temperature environment, and the high-temperature and low-temperature performance of the battery is cooperatively improved by matching with an electrolyte additive.
10. The ultra-large cylindrical sodium ion battery structure and safety cooperative system according to claim 1, further comprising a lug welding stress eliminating and oxidation preventing module, wherein the lug is made of aluminum, an oxidation layer is removed through surface pretreatment before welding, inert gas is covered in the whole process during welding, welding stress is eliminated through cold pressing treatment after welding, and connection impedance between the lug and a current collecting disc is strictly controlled.

Description

Oversized cylindrical sodium ion battery structure and safety cooperative system Technical Field The invention relates to the technical field of sodium ion battery structures and safety control, in particular to an oversized cylindrical sodium ion battery structure and a safety cooperative system. Background The ultra-large cylindrical sodium ion battery has wide application prospect in scenes such as large energy storage power stations, low-speed power batteries, truck start-up power sources and the like by virtue of the advantages of high integration level, low PACK cost and the like, the diameter of the ultra-large cylindrical sodium ion battery is generally covered with 65-500 mm, the length of the ultra-large cylindrical sodium ion battery is 100-1200 mm, and a NFPP iron-based composite polyanion phosphate anode and hard carbon cathode system is subjected to core adaptation. However, the prior art has a disadvantage in the cooperative matching of "material-structure-process-safety", which results in difficulty in considering battery performance, life and safety, and is a bottleneck restricting the large-scale application thereof, and these problems are not effectively solved by the prior published patent. The serious disjointing of the current collecting system and the positive and negative electrode material characteristics is a primary problem. The spoke type current collecting disc disclosed by the prior patent adopts a homogeneous aluminum material and an equal width spoke design, and does not consider the difference between the high current density required by the NFPP positive electrode polyanion frame and the low current density corresponding to the interlayer storage of the hard carbon negative electrode, so that the polarization voltage of the NFPP positive electrode is obviously increased under the multiplying power of more than 1C, and the capacity attenuation is obvious. Meanwhile, the current collecting disc is single in material and high in contact resistance, so that the problem of uneven current distribution is further aggravated, and the rate performance and the cycle stability of the battery are affected. The core rod function singleization and the poor process-material compatibility further restrict the battery performance. The existing hollow core rod only bears the support function of the winding core, the problem of uneven diffusion of the electrolyte of the oversized cylindrical battery cannot be solved, the electrolyte is soaked for too long due to the closed pore structure of the hard carbon negative electrode, the production efficiency is seriously affected, the core rod lacks the temperature adjusting capability, sodium ion migration is blocked in a low-temperature environment, and the low-temperature capacity retention rate of the battery is poor. In the process, the existing coating process adopts a fixed spray head and a homogeneous feeding mode, the characteristic that NFPP nanometer particles are easy to agglomerate is not considered, so that the uniformity of an electrode coating is poor, a carbon coating layer of a NFPP anode can be damaged by a traditional high-temperature welding process, the conductivity of the electrode is reduced, and the impedance after welding of a tab lacks an effective monitoring and correcting mechanism, so that the current conduction efficiency is influenced. The response delay of the safety system is the most prominent hidden trouble in the prior art. The side wall rupture membrane of the existing battery only depends on single pressure triggering, is not combined with the positive and negative electrode low-gas production characteristics and actual thermal runaway test data, has overlong pressure release response time under abnormal conditions, is easy to cause local bulge of the shell, and even causes safety accidents. In addition, the existing safety system lacks hierarchical protection design, only can realize the pressure release function, can't deal with the risk of probably taking place after the pressure release, and safety protection chain is incomplete. These drawbacks are superimposed on each other, so that the existing oversized cylindrical sodium ion battery is difficult to meet the comprehensive requirements of practical application on performance, service life and safety, and a set of full-chain innovative integrated solution is needed. Disclosure of Invention The invention provides an oversized cylindrical sodium ion battery structure and a safety cooperative system, which are used for solving the problems in the prior art. In order to achieve the purpose, the invention adopts the following technical scheme that the ultra-large cylindrical sodium ion battery structure and the safety cooperative system comprise the following modules: The double-gradient self-adaptive current collecting disc adopts spoke design with wide center and narrow edge, the base material is an aluminum-based composite layer and is covered with a nano t