What's a lithium battery conductor?

With the increasing commercialization of lithium batteries, the charging and discharging process of lithium batteries on the surface of positive materials is when the batteries are discharged, and the lithium ions in Kongzhong enter the positive polar active material. If the current increases, polarization increases., discharge is difficult, In this way, the electrical conductivity between electrons is poor, and the conductivity of the active material in the province is far from enough. In order to ensure that the electrode has good charging and discharging performance, a certain amount of electrical conductivity is usually added when the electrode is made. Between the active substances and the collection fluid plays a role in collecting microcurrents.

1 . Overview of electrical conductivity

As a conductive material for lithium-ion batteries, conventional conductive agents SUPER-P, KS-6, conductive graphite, carbon nanotubes, graphene, carbon fiber VGCF, etc. are mainly used. These conductive agents have their own advantages and disadvantages.

2. Application of conductive agents

1, SP

At present, the domestic lithium-ion battery conductive agent is still based on conventional conductive agent SP. Carbon black has better Ionic and electron conductivity, because carbon black has a larger specific surface area, so it is conducive to electrolyte adsorption and increase ion conductivity. In addition, the formation of a branching structure of primary carbon particles can form a chain conductive structure with the active material, which helps to improve the electron conductivity of the material.

2, graphite conductive agent

It is basically artificial graphite. Compared with artificial graphite of negative electrode material, artificial graphite as a conductive agent has a smaller particle size, which is conducive to the compaction of polar particles and the improvement of ion and electronic conductivity.

3, CNT conductive agent

The proportion of applications in the high-end digital battery field is as high as 50 %, and the proportion of applications in the power battery field is relatively low. However, in recent years, with the gradual improvement of the performance requirements of power cells such as energy density, rate performance, and cycle life, the proportion of CNT conductors applied in this field is gradually increasing.

4, Keqin black

Keqin black only needs a very low amount of addition to achieve high conductivity, so Keqin black has always been the best in conductive carbon black, and has long been in the leading position in the market. Compared with other conductive carbon black used in batteries, Keqin black has a unique branch-like shape. The advantage of this form is that the conductive contact points of the conductor are many, and the branches form more conductive pathways, so that only a small amount of addition is required to achieve a very high conductivity(other carbon black is mostly spherical or flaky). Therefore, a high amount of addition is required to achieve the required electricity). Keqin black is a Super conductive carbon black that is currently at the forefront. At present, the top 10 of lithium electricity are basically used or tested. Among them, EC-300J is mainly used for nickel-metal hydride and nickel-cadmium batteries; ECP and ECP-600JD are mainly used for lithium power with high power and current density, of which ECP-600JD is particularly prominent. The industry generally believes that its superior conductivity and high purity and unique branching structure will emerge in the era when ferrolithium is a positive material. There are two kinds of products used in the battery: CarbonECP and CarbonECP600JD, CP300JD.

3. Conductor content

A) The role of the conductive agent in the electrode is to provide a channel for the movement of electrons. The appropriate content of the conductive agent can achieve higher discharge capacity and better recycling performance. If the content is too low, the electron conductive channel is less, which is not conducive to high current charge and discharge; Too high reduces the relative content of the active substance and reduces the battery capacity.

B) The presence of conductive agents can affect the distribution of electrolytes within the battery system. Due to the space constraints of lithium-ion batteries, the amount of electrolytes injected is limited and is generally in a poor state. The electrolyte is the ion body connected to the positive and negative poles inside the battery system. Its distribution has a vital influence on the migration and diffusion of lithium ions in liquid phase. When the content of the conductive agent in one end of the electrode is too high, the electrolyte enrichment at this pole causes the lithium ion transmission process at the other pole to be slow, the degree of polarization is high, and it is easy to fail after repeated cycles, thus affecting the overall performance of the battery.

C) When the content of the conductive agent reaches a turning point, too much will only reduce the electrode density and reduce the capacity, while too little will lead to the low utilization of active substances in the electrode and the high rate of discharge performance.

4. Conductor outlook

GGII analysis believes that currently carbon nanotubes and graphene can be made into conductive slurry, which is much more expensive than ordinary carbon black SP. Carbon black is a very mature conductive agent and the price is relatively stable. With the increase of the scale effect, CNT and graphene have a relatively large space for price decline in the future, and their future application prospects are objective.

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