Integrated cell prelithiation device and method

Abstract

The present invention provides an integrated cell prelithiation apparatus and method for performing batch prelithiation on battery cells using a lithium source half electrode by an electrochemical method. The prelithiation apparatus includes a prelithiation work box and an external power source. The prelithiation work box includes a housing, a cell fixing element installed in the housing, a lithium source half electrode, a negative electrode bus bar including a negative electrode strap for simultaneously communicating with the negative electrodes of multiple battery cells, and a lithium source bus bar for communicating with the lithium source half electrode. A circuit connects the negative electrodes of the battery cells to the lithium source half electrode and the external power source, and electrochemical lithium replenishment is performed under the action of the external power source. The prelithiation apparatus of the present invention is simple to operate and easy to implement, making it possible to perform batch prelithiation.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to the field of battery technology, and in particular to an apparatus and method for prelithiation of integrated cells.

[0002] [Background technology] As society develops, the application of electrochemical energy storage devices is receiving increasing attention. Limited by material quality, the initial charge / discharge efficiency of electrochemical energy storage device cells is gradually becoming low, necessitating the urgent development of technologies to compensate for this low initial charge / discharge efficiency. The emergence of prelithiation (lithium replenishment) has solved this problem. Currently, the main methods of lithium replenishment are positive electrode lithium replenishment, negative electrode lithium replenishment, chemical lithium replenishment, and electrochemical lithium replenishment. Positive electrode lithium replenishment mainly uses perlithiated compounds as additives, but the addition of these substances introduces inactive components and reduces energy density. Negative electrode lithium replenishment is mainly performed using lithium powder and ultra-thin lithium foil. However, lithium powder has a large particle size (D50≧40μm), is classified as explosive dust, and is highly hazardous. Lithium foil replenishment requires high processing requirements for ultra-thin lithium foil, making it difficult for ordinary companies to produce. Conventional chemical lithium replenishment and electrochemical lithium replenishment involve lithium replenishment of a single pole piece, which results in low efficiency and makes it unsuitable for batch prelithiation and large-scale applications. Therefore, there is a need to develop a large-scale, simple method for lithium replenishment.

[0003] Summary of the Invention The present invention provides a simple and effective batch prelithiation apparatus and method, which can effectively solve the drawbacks of the current prelithiation process.

[0004] The object of the present invention is achieved by the following technical solutions.

[0005] According to one aspect of the present invention, A pre-lithiation work box and an external power supply are included. The prelithiation work box is The housing and A cell fixing element and a lithium source half electrode installed in a housing; a negative electrode bus bar including a negative electrode strap for simultaneously communicating with the negative electrodes of the plurality of battery cells, and a lithium source bus bar for communicating with the lithium source half-electrodes; The cell fixing element includes a plurality of cell fixing rings or a plurality of tab fixing elements for fixing the plurality of battery cells, each tab fixing element for fixing a negative electrode tab of each battery cell, the plurality of tab fixing elements communicate with a negative electrode strap, and The positive electrode of the external power source is connected to the negative bus bar, and the negative electrode of the power source is connected to the lithium source bus bar; A prelithiation device is provided.

[0006] The prelithiation device of the present invention is applicable to the prelithiation of cylindrical cells and polygonal cells (rectangular cells), as well as the prelithiation of stacked cells, and can realize the prelithiation of multiple cells simultaneously. The number of cells depends on the size of the prelithiation work box, which is inexpensive and can be expanded according to actual needs.

[0007] Alternatively, the battery cell may include a cylindrical cell, a wound rectangular cell, or a stacked cell, and the negative electrode side of the cylindrical cell or the wound rectangular cell may include a pole, and the cell may be fixed with a cell fixing element and then communicate with a negative electrode strap via the pole, and the negative electrode side of the stacked cell may include a negative electrode tab, and the stacked cell may be fixed by fixing the negative electrode tab with the tab fixing element.

[0008] Optionally, the cell is a wound cylindrical cell, and the negative electrode side thereof is spin-formed and the negative electrode current collector and the electrode post are welded together. The cell is preferably an 18650, 21700, or 46800 cell.

[0009] Optionally, the cell is a wound, stacked polygonal cell, the number of sides of which is four or more, and the negative electrode is led out by a dab welding method.

[0010] Optionally, the cell fixing element is a plate-like element fixed within the housing, and the plate-like element has a plurality of circular rings or polygonal rings penetrating the plate-like element in the thickness direction so that a plurality of cells and lithium source half electrodes can be arranged.

[0011] Optionally, the lithium source half electrode is composed of a metallic lithium rod or metallic lithium block and a current collector, and the purity of the metallic lithium reaches 99.99% or more.

[0012] Optionally, the bottom of the housing further has a bottom groove for inserting a lithium source half electrode.

[0013] Optionally, the prelithiation device further includes a liquid storage device for supplying electrolyte to the prelithiation work box.

[0014] Optionally, the prelithiation work box further includes a liquid inlet, a liquid outlet, and a liquid position sensor. 。

[0015] Selection Optionally, the integrated cell prelithiation apparatus further includes an environmental control device that provides a vacuum environment or an inert atmosphere protective environment within the enclosure.

[0016] Optionally, the environmental control device is a vacuum device or a gas replacement device, and can provide a vacuum environment or an inert gas environment in the enclosure, and the inert gas environment is preferably an argon gas environment.

[0017] Optionally, the apparatus further includes a control system that controls at least one of the power supply voltage, current, prelithiation time, liquid position in the prelithiation work box, environmental control device, and environmental parameters in the prelithiation work box.

[0018] Optionally, the prelithiation work box is a sealed enclosure that can be opened or closed or has a removable side.

[0019] Alternatively, the negative electrode strap is provided inside the housing, and the prelithiation work box is provided with a pole that penetrates the top cover of the housing, and when the top cover is closed, the pole communicates with the negative electrode strap, or the negative electrode strap is provided outside the housing and communicates with the negative electrode of the battery cell via the pole that penetrates the housing.

[0020] Alternatively, a negative electrode strap may be placed inside the housing on the negative electrodes of the cells, for example, secured under the top cover of the housing. Preferably, the negative electrode strap is automatically controlled and can be opened or closed by an electrical signal when a cell is detected to be in position, thereby realizing opening or clamping operations on the cell poles.

[0021] Optionally, the tab securing member is at least one of a clip, a pawl, a jaw, and a securing plate.

[0022] According to another aspect of the present invention, there is provided a method for performing cell-integrated prelithiation using the prelithiation apparatus, comprising the steps of: Attaching a plurality of cells to a cell fixing element and connecting a negative electrode of each cell to a negative electrode strap; pouring an electrolyte solution through the electrolyte solution inlet until the cell and the lithium source half-electrode are completely immersed in the electrolyte solution; and controlling the amount of prelithiation by turning on an external power source and controlling the magnitude and duration of the current. A cell integration prelithiation method is provided.

[0023] Alternatively, the electrolyte is a conventional electrolyte for lithium batteries, preferably a carbonate ester solvent and lithium hexafluorophosphate salt.

[0024] Optionally, the control system controls the discharge of a small current to a half-cell consisting of the cell negative electrode and the lithium source half-electrode, preferably the current is 0.2C.

[0025] According to yet another aspect of the present invention, there is provided a lithium battery comprising a prelithiated cell made by the above method.

[0026] The technical solution of the present invention has at least one of the following advantages:

[0027] It is possible to simultaneously perform integrated prelithiation on multiple battery cells, resulting in high production efficiency and low cost, and achieving better consistency and uniformity in negative electrode prelithiation compared to conventional prelithiation equipment. The integrated cells prelithiated by the prelithiation device of the present invention can be directly taken out and packaged into a battery after simple processing, which makes the process simple. The present invention has low requirements for the lithium source half electrode, and has significant advantages in manufacturability and cost.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an integrated cell prelithiation apparatus of the present invention.

[0029] Figure 2 is a schematic diagram of the structure of the cylindrical cell prelithiation work box.

[0030] FIG. 3 is a structural schematic diagram of the box for prelithiation work of stacked cells.

[0031] (Explanation of symbols) 10 Prelithiation work box 11 Housing 12 Cell fixing element 13 Negative electrode strap 14 negative electrode bus column 15 lithium source bus column 16 liquid inlet 17 liquid outlet 18 Liquid position sensor 19 Environmental control port 20 Cell 21 Negative tab 22 positive electrode tab 30 lithium source half electrode 31 bottom groove 32 tab fixing element 40 power supply 41 positive power supply 42 negative power supply 50 environmental control device 60 liquid storage device 61 liquid injection pump 70 control system 71 control screen [Mode for Carrying Out the Invention] Specific embodiments of the present invention will be described below with reference to the drawings. It should be understood that those skilled in the art can imagine and modify various other embodiments in accordance with the teachings of the present disclosure without departing from the scope or spirit of the present disclosure. Therefore, the following detailed description is not meant to be limiting.

[0032] FIG. 1 is a schematic diagram showing one specific embodiment of the integrated cell prelithiation apparatus of the present invention, and FIG. 2 is a specific embodiment of the prelithiation work box in the integrated cell prelithiation apparatus.

[0033] Referring to Figures 1 and 2, the integrated cell prelithiation device a plurality of cylindrical integrated cells 20, each including a negative electrode post and a positive electrode tab; a lithium source half electrode 30 consisting of metallic lithium and a current collector; a cell fixing element 12, which is a metal element (e.g., an aluminum element) having a plurality of circular or square fixing grooves (or holes) penetrating the element, a portion of which is used to fix a cylindrical integrated cell 20 and another portion (at least one portion) of which is used to fix a lithium source half electrode 30; a negative electrode strap 13; a negative electrode bus column 14; a lithium source bus column 15; a liquid inlet 16 for injecting an electrolyte into the prelithiation work box 10; a liquid outlet 17 for discharging waste electrolyte from the casing after prelithiation is completed; a liquid position sensor 18; and an environmental control port 19. The prelithiation work box 10 further includes a bottom groove 31 for fixing the bottom of the lithium source half electrode 30. A power source 40 having a power source positive electrode 41 and a power source negative electrode 42, the power source positive electrode 41 communicating with the negative electrode bus column 14 via a conductor, and the power source negative electrode 42 communicating with the lithium source bus column 15 via a conductor; In this embodiment, the environmental control device 50 is a vacuum device connected to the environmental control port 19 in the prelithiation work box 10, and can put the prelithiation work box 10 into a vacuum state, and the vacuum degree is preferably less than 100 Pa. In some other embodiments, the environmental control device 50 may be a gas replacement device, and can replace the gas in the prelithiation work box 10 to maintain the inside of the prelithiation work box 10 in an inert gas environment. a liquid storage device (60) used to store an electrolyte, the liquid injection pump (61) being connected to the liquid injection port (16) of the prelithiation work box (10), so that the liquid injection pump (61) is operated to pump the electrolyte in the liquid storage device (60) into the prelithiation work box (10); and a control system 70 which is used to control the relevant parameters of each stage and further includes a control screen 71 through which relevant parameters to be controlled, prelithiation time, etc. can be input and set.

[0034] During specific operation, after confirming that there is no electrolyte in the prelithiation work box 10 (if there is electrolyte, it is discharged through the liquid outlet 17), the prelithiation work box 10 is first opened, the lithium source half-electrode 30 is passed through the cell fixing element 12 and fixed to the bottom groove, and the cylindrical cell 20 to be prelithiation is passed through the cell fixing element 12 and placed on the floor. An upper lid with a bus column is then placed on top, and the bus column 14 is connected to the negative electrode strap 13, and the negative electrode strap clamps multiple cell poles with a clamp at its lower end, connecting the lithium source bus column 15 to the lithium source half-electrode poles.

[0035] The prelithiation work box 10 is sealed, and the environmental control device 50 maintains the prelithiation work box 10 at a set work environment. The liquid injection pump 61 pumps the electrolyte into the prelithiation work box 10 until the set value is reached (usually, the liquid position of the electrolyte reaches the position of the negative electrode pole 21 of the integrated cell 20). After setting the relevant prelithiation parameters on the control screen 71, the control system 70 controls the power supply 40 to start prelithiation of multiple sets of integrated cells 20. After prelithiation is completed, the electrolyte in the prelithiation work box 10 is discharged through the liquid discharge port 17, the housing 11 is opened, and the prelithiated integrated cells 20 are removed from the prelithiation work box 10 and subjected to relevant processing before being assembled into batteries.

[0036] FIG. 3 shows another specific embodiment of the prelithiation work box in the integrated cell prelithiation device. The difference from FIG. 2 is that the battery cell is a stacked cell and the cell is fixed by a tab fixing element. Specifically, the integrated cell prelithiation device includes an integrated cell 20 including a negative electrode tab 21 and a positive electrode tab 22, a lithium source half-electrode 30 made of metallic lithium and a current collector, a prelithiation work box 10, and a power source 40 having a power source positive electrode 41 communicating with the negative electrode strap 14 via a conductor and a power source negative electrode 42 communicating with the lithium source strap 15 via a conductor. The prelithiation work box 10 includes a sealable housing 11, a tab fixing element 32, a negative electrode strap 13, a negative electrode bus column 14, The prelithiation work box 10 includes a lithium source strap 15, a liquid inlet 16 for injecting electrolyte into the prelithiation work box 10, a liquid outlet 17 for discharging waste electrolyte from the housing after prelithiation is completed, a liquid position sensor 18, and an environmental control port 19. There are multiple tab fixing elements 32, some of which are used to fix the negative electrode tab of the integrated cell 20, and another part (at least one) of which is used to fix the tab of the lithium source half electrode 30. The tab fixing element 32 for fixing the lithium source half electrode 30 communicates with the lithium source strap 15 via a corresponding electrode column, and the tab fixing element 32 for fixing the negative electrode tab 21 in the integrated cell 20 communicates with the negative electrode strap 13 via a corresponding negative electrode bus column 14.

[0037] It should be understood that the above are only preferred embodiments of the present invention, and do not limit the present invention, and any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic diagram of an integrated cell prelithiation device of the present invention. [Figure 2] FIG. 1 is a structural schematic diagram of a cylindrical cell prelithiation work box. [Figure 3] FIG. 1 is a structural schematic diagram of a box for prelithiation work of a stacked cell.

Claims

1. A pre-lithiation work box and an external power supply are included. The prelithiation work box is The housing and A cell fixing element and a lithium source half electrode installed in a housing; a negative electrode bus bar including a negative electrode strap for simultaneously communicating with the negative electrodes of the plurality of battery cells, and a lithium source bus bar for communicating with the lithium source half-electrodes; The cell fixing element includes a plurality of cell fixing rings or a plurality of tab fixing elements for fixing the plurality of battery cells, each tab fixing element for fixing a negative electrode tab of each battery cell, the plurality of tab fixing elements communicate with a negative electrode strap, and The positive electrode of the external power source is connected to the negative bus bar, and the negative electrode of the power source is connected to the lithium source bus bar; A prelithiation apparatus characterized by:

2. The battery cells include cylindrical cells, wound rectangular cells, or stacked cells, and the negative electrode side of the cylindrical cells or wound rectangular cells includes a pole, and the cell can be fixed with a cell fixing element and then communicate with a negative electrode strap via the pole, and the negative electrode side of the stacked cells includes a negative electrode tab, and the stacked cells can be fixed by fixing the negative electrode tab with the tab fixing element.

2. The prelithiation apparatus according to claim 1 .

3. the cell fixing element is a plate-like element fixed in a housing, and the plate-like element has a plurality of circular rings or polygonal rings penetrating the plate-like element in a thickness direction so that a plurality of cells and a lithium source half electrode can be arranged; 2. The prelithiation apparatus according to claim 1 .

4. The lithium source half electrode is composed of a metal lithium rod or a metal lithium block and a current collector, and the purity of the metal lithium reaches 99.99% or more; 2. The prelithiation apparatus according to claim 1 .

5. The bottom of the housing further has a bottom groove for inserting a lithium source half electrode.

2. The prelithiation apparatus according to claim 1 .

6. The prelithiation device further includes a liquid storage device for supplying electrolyte to the prelithiation work box; 2. The prelithiation apparatus according to claim 1 .

7. The prelithiation work box further includes a liquid inlet, a liquid outlet, and a liquid position sensor.

2. The prelithiation apparatus according to claim 1 .

8. The prelithiation apparatus further includes an environmental control device that provides a vacuum environment or an inert atmosphere protective environment inside the enclosure.

2. The prelithiation apparatus according to claim 1 .

9. The prelithiation apparatus further includes a control system, which controls at least one of a power supply voltage, a current, a prelithiation time, a liquid position in the prelithiation work box, an environmental control device, and an environmental parameter in the prelithiation work box.

2. The prelithiation apparatus according to claim 1 .

10. The pre-lithiation work box is a sealed housing that can be opened and closed or has a removable surface.

2. The prelithiation apparatus according to claim 1 .

11. the negative electrode strap is provided in the housing, and the prelithiation work box is provided with a pole that penetrates a top cover of the housing, and when the top cover is closed, the pole communicates with the negative electrode strap; Or, the negative electrode strap is provided on the outside of the housing and communicates with the negative electrode of the battery cell via a pole that penetrates the housing; 2. The prelithiation apparatus according to claim 1 .

12. The tab securing element is at least one of a clip, a pawl, a jaw, and a securing plate.

2. The prelithiation apparatus according to claim 1 .

13. A method for performing cell-integrated prelithiation using the prelithiation device according to any one of claims 1 to 12, comprising: Attaching a plurality of cells to a cell fixing element and connecting a negative electrode of each cell to a negative electrode strap; pouring an electrolyte solution through the electrolyte solution inlet until the cell and the lithium source half-electrode are completely immersed in the electrolyte solution; and controlling the amount of prelithiation by turning on an external power source and controlling the magnitude and duration of the current. A cell integration prelithiation method characterized by:

14. 14. A prelithiated cell produced by the method of claim 13. A lithium battery characterized by:

Images