Development of lithium ion batteries, lithium ion battery design

Lithium-ion battery design consists of two aspects, mechanical dimensioning design and electrochemical system design.

The mechanical size design mainly involves the size of the battery and the size of the battery accessories: the size of the packaging bag, the size of the pole piece and the relationship between all dimensions.

The design of mechanical dimensions is fixed parameters, which are highly process-dependent and energy-density-sensitive.

The design of the electrochemical system is about what kind of material combinations are selected for different scenarios and applications, and how to set the relevant parameters of these materials. For example, the coating weight, compaction density, liquid injection amount, etc., the combination of these parameters determines the performance of the battery. (The system is the core secret of lithium-ion batteries, and it is inconvenient to disclose.)

A good designer needs to have an accurate grasp of these parameters and the relationship between them in order to make a perfect design. The most difficult thing is the design of the chemical system, which is the core competitiveness of lithium battery companies.

Lithium-based batteries are divided into lithium batteries and lithium-ion batteries. Mobile phones and laptops use lithium-ion mid-shed batteries, which are commonly referred to as lithium batteries. Batteries generally use materials containing lithium as electrodes, which are the representatives of modern high-performance batteries.

However, real lithium batteries are rarely used in daily electronic products due to their high danger.

Lithium-ion batteries were first developed by Sony Corporation of Japan in 1990. It is the embedding of lithium ions into carbon (petroleum coke and graphite) to form an anode (traditional lithium batteries use lithium or lithium alloy as the anode). LixCoO2 is commonly used for cathode materials, LixNiO2 is also used, and LixmNO4 is used, and Lipf6 + diethylene carbonate (EC) + dimethyl carbonate (DMC) is used for electrolyte.

Petroleum coke and graphite as anode materials are non-toxic, and the resources are sufficient, lithium ions are embedded in carbon, overcome the high activity and difference of lithium, solve the safety problems of traditional lithium batteries, and the cathode LixcoO2 can reach a high level in charge and discharge performance and life, so that the cost is reduced, in short, the comprehensive performance of lithium-ion batteries is improved. It is expected that lithium-ion batteries will occupy a large market in the 21st century.

The reaction formula of lithium-ion secondary battery when charging and discharging is LiCoO2+C=Li1-XCOO2+LiXC

Millions of car purchase subsidies.

Lithium-ion tung car wide pool has a dominant position in mobile terminals, but the market is not large, only tens of billions. But even in these tens of billions of markets, the demand for lithium batteries is varied.

Mobile phone battery,Spoiled by the hand game bright machine manufacturer,Resulting in higher and higher charging requirements now,In fact, half an hour of charging is fast enough,But the manufacturer is still not satisfied,Xiaomi has challenged 200W,The sail bench feels out of actual demand。

Notebook batteries do not have high requirements for charging, mainly the consistency of the battery and the requirements of high-temperature floating charge, after all, they have been working at high temperatures.

Tablet batteries, similar to mobile phones, have higher battery life requirements, but they don't care about fast charging, traditionally speaking, good circulating graphite plus lithium cobalt oxide is enough.

Wearing a battery, here in the face of health concerns to engage in this market fire, the battery requires fast charging, long cycle, basically the same as the mobile phone. In addition, the headphones have blown out hard-shell batteries, creating a new ** chain.

The drone battery, the ultimate discharge rate, which is related to its application scenario, is understandable, so for it, the material is specially designed. Fortunately, agricultural drones have made the market a little bigger.

The mobile power supply mainly uses ternary plus cheap graphite, which fortunately coincides with the power battery, so that we don't have to worry about his material.

Therefore, there are many small factories that pick up leaks in lithium batteries, and they can survive very well even by relying on technology. But this characteristic determines that it is difficult for them to become bigger.