Patent Application
20190214627
This invention relates to an apparatus and a method of treating lithium-ion battery parts, including, but not limited to, positive electrodes, negative electrodes, separators, copper foils and aluminium foils.
With the development of lithium-ion batteries, more and more research has been carried out in the hope of increasing the electric capacity and life of such batteries. It is known that addition/deposition of lithium monomers, lithium oxides and/or lithium-containing metal alloys onto the negative electrodes of such batteries are effective in increasing the electric capacity and life of such batteries. The existing lithium-filling methods carried out on negative electrodes of lithium-ion batteries include spraying lithium powder or sticking a piece of lithium tape on the negative electrodes. The former method suffers from inconsistent effect, non-compactness and non-continuousness; whereas for the latter method, as existing lithium tapes are of a thickness of 20 to 30 μm, such are too thick as they occupy too much space in the lithium-ion batteries.
It is thus an object of the present invention to provide an apparatus and a method of treating a lithium-ion battery part in which the aforesaid shortcomings are mitigated or at least to provide a useful alternative to the trade and public.
According to a first aspect of the present invention, there is provided an apparatus for treating a lithium-ion battery part, including means for depositing lithium onto said battery part by physical vapour deposition and/or chemical vapour deposition.
According to a second aspect of the present invention, there is provided a method of treating a lithium-ion battery part, including (a) providing a lithium-ion battery part, and (b) depositing lithium onto said component by physical vapour deposition and/or chemical vapour deposition.
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
An apparatus for treating a lithium-ion battery part according to an embodiment of the present invention is shown in
As shown in
The vacuum system chamber 103 includes magnetron sputtering systems 203, a chemical vapour deposition system 204, an arc discharge system 205, an ion-beam and resistance type evapouration coating system 206, a heating system 207, a workpiece cooling system 210, and a coating thickness monitoring system 211.
In operation, the workpiece (e.g. the electrode 212) is fed from the workpiece feeder 201 through the channel 220a into the vacuum system chamber 103 to undergo magnetron sputtering by the magnetron sputtering systems 203, and/or chemical vapour deposition by the chemical vapour deposition system 204, and/or arc discharge by the arc discharge system 205, and/or evapouration coating by the ion-beam and resistance type vapouration coating system 206. After undergoing such treatment process(es), the workpiece is conveyed through the channel 220b and wound around the workpiece collector 202 for collection purposes.
If necessary or desirable, it is possible to set the apparatus 100 to operate in another operation mode such that after winding of the electrode 212 onto the workpiece collector 202, the workpiece collector 202 is set to rotate in the counter-clockwise direction (in the sense of
The apparatus 100 may be connected, upstream and/or downstream, with other equipment for the production of lithium-ion batteries, to form a fully-automated or partly-automated continuous lithium-ion battery production line, or a fully-automated or partly-automated vacuum type production system. Such other equipment may include cloth spraying, rolling, punching, winding, casing insertion, and/or liquid injecting machines.
Tests have been conducted to analyze the relevant characteristics of lithium-ion battery parts treated by the apparatus 100 and the method according to the present invention. In particular, negative electrodes of lithium-ion battery were produced by placing conventional negative electrodes into the workpiece feeding and collection chamber 102. The vacuum pumping assembly 101 was activated to reduce the pressure in the workpiece feeding and collection chamber 102 and vacuum system chamber 103 to not more than 5.0×10−3 Pa. The apparatus 100 was then pre-heated by the heating system 207 to 100° C. The power transmission system 104 was activated to feed the negative electrode through the channel 220a into the vacuum system chamber 103 to be treated by the magnetron sputtering systems 203, in which the magnetron sputtering negative electrode power was set at 2 kW. During the magnetron sputtering process, a biasing voltage of −150 V was set. After treatment in the vacuum system chamber 103, the treated negative electrode was wound around the workpiece collector 202.
The negative electrode workpiece treated as discussed in the immediately preceding paragraph was used for forming soft package lithium-ion batteries for testing purposes. In the tests, LiCoO2 was used as the positive electrode, to provide consistency. A total of eight battery samples were produced. Samples 1 to 4 were conventional lithium-ion batteries, in which the positive electrodes were made of LiCoO2 and the negative electrodes were conventional negative electrodes. Samples 5 to 8 include negative electrodes treated as discussed in the immediately preceding paragraph. In particular, such negative electrodes were conventional negative electrodes (as those used in forming Samples 1 to 4) further treated as discussed in the immediately preceding paragraph. The positive electrodes of Samples 5 to 8 were also made of LiCoO2, as in the case of Samples 1 to 4. All other parameters of Samples 1 to 8 were identical.
Tables 1 and 2 below show relevant testing results of Samples 1 to 4 and Samples 5 to 8 respectively:
It can be seen from the foregoing test results that:
It was also found that as compared with Samples 1 to 4, Samples 5 to 8 exhibit the advantages/improvements of having a smoother surface, with no black stains, thus mitigating the lithium-release problem.
It was also found that lithium was deposited onto the negative electrode by a depth of up to 100 μm and of a width of up to 2000 mm.
Although the invention has thus far been discussed in the context of treating negative electrodes of lithium-ion batteries, it is envisaged that:
It should be understood that the above only illustrates an example whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention. It should also be understood that various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any appropriate sub-combinations.
