Multilayer positive plate, production method of positive plate and lithium ion battery

Abstract

The invention discloses a multilayer positive plate. The multilayer positive plate comprises a current collector and an electrode material layer which is smeared on the surface of the current collector; the electrode material layer comprises one or more than one mixed sizing agent layer; the mixed sizing agent layer is gradually smeared on the surface of the current collector layer by layer. The invention discloses a production method of the multilayer positive plate. The invention also discloses a lithium ion battery. The positive plate adopts a multilayer structure, different layers can be made of identical or different electrode materials, so that the utilization rate of the positive active material can be increased, the utilization rate of the positive material can reach 95 to 98 percent, and the gram volume can be increased; by adding the active material coating with stable structure and good safety performance, the utilization rate of the material is increased, and the safety performance of the lithium ion battery also can be improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a multilayer positive electrode sheet, a method for making the positive electrode sheet and a lithium ion battery. Background technique [0002] At present, the lithium-ion battery manufacturing industry generally uses graphite negative electrodes and alloy negative electrodes as negative electrode materials. After charging, due to the loss of film formation, the loss of lithium sources leads to the attenuation of the gram capacity of positive electrode materials, resulting in a low utilization rate (about 92%). In reality, half-battery tests show that the utilization rate of the positive electrode material can reach about 98%, and nearly 6% of the active materials are pure waste of resources, such as lithium cobalt oxide, lithium iron phosphate, lithium manganate, etc. At present, the mature technology is mainly mixed positive electrodes, such as lithium cobalt oxi...

AI Technical Summary

Problems solved by technology

[0002] At present, the lithium-ion battery manufacturing industry generally uses graphite negative electrodes and alloy negative electrodes as negative electrode materials. After charging, due to the loss of film formation, the loss of lithium sources leads to the attenuation of the gram capacity of positive electrode materials, resulting in a low utilization rate (about 92%). In reality, the half-battery test shows that the utilization rate of the positive electrode material can reach about 98%, and nearly 6% of the active materials are pure waste of resources, such as lithium cobaltate, lithium iron phosphate, lithium manganate, etc.

At present, the mature technology is mainly mixed positive electrodes, such as lithium cobalt oxide mixed with lithium nickel cobalt manganese oxide or lithium nickel manganese oxide, lithium manganate mixed with lithium nickel cobalt manganese oxide, etc. Although this method can improve the utilization rate of materials, However, the remaining excellent properties of the material cannot be brought into play, and some even deteriorate

The processing cost is higher than before mixing, such as rate performance decline, compaction reduction, conductivity reduction, high internal resistance, etc., resulting in the loss of one another; in addition, the safety performance of different lithium-ion battery positive electrodes is different, among which lithium cobaltate, nickel Materials such as lithium cobalt manganese oxide are less safe, and lithium manganese oxide and lithium iron phosphate have better safety performance. If the materials are directly mixed together, the effect of improving safety performance cannot be achieved, and the use of multi-layer coating can be significantly improved. Battery safety performance

Images