Development situation of power lithium battery technology -Lithium - Ion Battery Equipment
One、 The current ternary and lithium iron phosphate battery technology is highly mature
1. Ternary and lithium iron phosphate batteries are the focus of enterprise layout
In the field of automotive power batteries, lithium batteries have become the mainstream. At present, the main battery types of international mainstream power battery enterprises are lithium iron phosphate and ternary lithium batteries.
From the perspective of the Chinese market, lithium iron phosphate and ternary batteries are still the mainstream of automotive power batteries, accounting for 94.5% and 93.3% of the total market in 2016 and 2017.
2. Lithium iron phosphate and ternary lithium battery still have a period of development
After a period of development, the technical level of lithium iron phosphate and ternary lithium battery has been significantly improved. In terms of cost, the price of lithium iron phosphate battery pack decreased from 1.8-1.9 yuan/Wh at the beginning of 2017 to 1.45-1.55 yuan/Wh at the end of 2017. The price of ternary power battery pack dropped from 1.7-1.8 yuan/Wh at the beginning of the year to 1.4-1.5 yuan/Wh at the end of the year.
In terms of energy density, at the end of 2017, based on NCM622 material, the energy density of single battery exceeded 200Wh/kg, and the system energy density was 160Wh/kg. It is estimated that the energy density of single battery could reach 230~250Wh/kg in 2018.
These two types of batteries still have some room for improvement, especially the role of new generation materials in improving battery performance, such as the research and development of positive material 811 and silicon carbon negative electrode, which will further improve the energy density of lithium power batteries. The energy density of individual batteries is expected to reach 300Wh/kg. In addition, the two types of batteries have a strong industrial foundation, and there will be a certain period of competition in the industry.
Two、 Solid state battery becomes the focus of current layout
From the perspective of technical potential, the theoretical energy density of lithium iron phosphate system is about 170Wh/kg, and the theoretical energy density of ternary lithium battery is 300-350Wh/kg. At the same time, there are safety problems such as low thermal decomposition temperature, easy combustion and explosion, and there is relatively little room for improving the energy density of both. However, the energy density of all solid state lithium battery has great potential to be improved, which is more feasible theoretically.
1. Potential technical advantages of solid-state lithium batteries
Compared with traditional lithium batteries, solid state lithium batteries are characterized by the use of solid electrolyte materials. When the electrodes and electrolyte materials used are solid and do not contain any liquid components, they are all solid state lithium batteries. Solid state electrolyte has changed the traditional structure of lithium battery. Diaphragm, liquid electrolyte and other components are no longer necessary, bringing huge technological advantages and potential.
The main technical advantages of solid state lithium battery are as follows: first, it has high safety, does not contain flammable, volatile and toxic organic solvents, does not have leakage problems, is expected to avoid the generation of lithium dendrites, and greatly reduces the risk of battery combustion and explosion. Second, the cycle life is long, and there is no problem that the liquid electrolyte produces solid electrolyte interface facial mask during the charge discharge cycle. At present, the expected life of research and development is 15000-20000 times. Third, the energy density is high. In traditional lithium batteries, the volume of separator and electrolyte accounts for 40%. Solid electrolyte can significantly reduce the distance between positive and negative electrodes of the battery and increase the volume specific energy. The maximum potential value of energy density of all solid lithium batteries is estimated to be 900Wh/kg. Fourth, the system has high specific energy density, and the solid electrolyte has no fluidity. It can form high-voltage monomer in series, which is conducive to improving the efficiency and energy density of the power battery system. Fifth, a wide range of positive and negative electrode materials can be selected, which can simultaneously use new technologies such as lithium metal cathode and high potential cathode materials. All solid metal lithium battery is the research and development direction of new battery in the future. In addition, solid state battery has a wide working temperature range, electrochemical stability window, and has the potential of thin-film and flexibility.
2. Global enterprises have deployed solid-state batteries to compete for the first opportunity
Due to the current bottleneck of lithium iron phosphate and ternary lithium batteries and the potential advantages of solid state batteries, many enterprises in the industrial chain involving power batteries, automobiles and energy in Europe, America, Japan, South Korea, China and other countries are actively planning and developing solid state batteries.
In general, European and American countries are mainly entrepreneurial companies based on solid state battery technology, while Japan is mainly engaged in battery technology innovation based on traditional automobile enterprises and machinery enterprises. Chinese enterprises entered the field of solid state lithium battery relatively late, and were mainly supported by scientific research institutions or universities, so the industrialization process was slow.
In terms of research and development, the main force in China is the scientific research institutions of the Chinese Academy of Sciences, which has accumulated to a certain extent and is basically at the same level as foreign countries. However, there is still much room to improve the energy density from the theoretical value, and the ionic conductivity and cycle life also need to be further improved. Solid state lithium battery is divided into three technical routes according to solid electrolyte, namely polymer, oxide and sulfide solid electrolyte. The technical routes adopted by various scientific research institutions are different. Among them, Qingdao Institute of Energy of the Chinese Academy of Sciences and Institute of Chemistry of the Chinese Academy of Sciences mainly focus on polymer solid lithium batteries. The energy density of experimental samples of the former reaches 300Wh/kg, and the deep-sea test was completed for the first time. The latter broke through the bottleneck of low conductivity of polymer solid electrolyte at room temperature; The research feature of the Institute of Physics of the Chinese Academy of Sciences is to master the in-situ formation technology. The energy density of the 10Ah soft pack battery developed is 310-390Wh/kg, and the specific volume energy is 800-890Wh/L; Ningbo Institute of Materials, Chinese Academy of Sciences and Shanghai Silicate Research Institute respectively focus on the research of inorganic solid state lithium battery and composite solid state lithium battery.(Lithium - Ion Battery Equipment)
3. Technical and industrial barriers need to be broken through
Through the research of enterprises and research institutions, the solid state battery technology has made a breakthrough at present, with the energy density exceeding 300Wh/kg, but most of them are laboratory products, which is still a certain distance from industrialization.
At the technical level, ionic conductivity of solid electrolyte, solid/solid interface compatibility and stability are still two major constraints. The conductivity of polymer electrolyte is low at room temperature, and it generally needs to be heated to above 60oC to work normally. For example, Bollor é in France adopts the technical route of polymer electrolyte and battery heating; At present, the conductivity of sulfide electrolyte is equivalent to that of traditional lithium battery, but it still needs to break through the interface phase problem, mainly through material synthesis and nano layer technology to increase the amount of active substances and reduce the interface layer resistance. At the same time, lithium metal anode and new composite cathode materials are still under development, which are expected to realize the application of all solid state lithium metal batteries. At that time, there will be a huge breakthrough in energy density, capacity, multiplying performance, safety performance and cycle life.
At the level of industrialization, the difficulties of failing to achieve large-scale production mainly lie in production equipment, production process and production line environment. For example, the lamination, coating and packaging processes in the preparation of solid-state batteries need customized high-precision equipment, and the production line environment also needs to maintain a higher level of drying room. The cost of solid state lithium battery will be reduced only after the large-scale production realizes the improvement of output and capacity.
On the whole, the production and preparation maturity of solid state lithium batteries needs to be strengthened, and large-scale and automated production lines need to be further developed, which is still in the industry accumulation period. The overall development path of solid state battery is: subject to the stability of solid/solid interface, the content of liquid electrolyte gradually decreases, and the battery transits from liquid to semi-solid → solid-liquid mixture → solid to all solid state battery; In terms of the development of all solid state lithium metal battery, due to the rechargeability of lithium metal anode, the anode material will transition from graphite → alloy anode (such as Si/C) → lithium metal anode. With the development of R&D technology and industrial production, the performance and production of solid state batteries will be gradually optimized, which will usher in opportunities in the power battery market.
3、 Potential technology substitutes still exist
In addition to the improvement of current lithium batteries and the layout of solid state batteries, domestic and foreign enterprises and institutions/universities have made different attempts in power battery technology innovation. Some indicators have been greatly improved compared with the current level, providing a strong reference for the improvement of power battery performance.
Through sorting out the technical indicators of typical innovation cases collected, it can be found that the key indicators of some products have been improved. In terms of energy density, the energy density of aluminum air battery reaches 780Wh/kg, lithium sulfur battery reaches 350Wh/kg, and solid state battery reaches 360Wh/kg; In terms of charging rate, the highest charging rate of typical innovative products has exceeded 100C. In terms of cycle life, typical innovative products have been able to exceed 15000 times.
The new battery has many advantages. First, in terms of technology, for example, the lithium sulfur battery uses sulfur as the cathode material, and the theoretical specific energy of the battery can reach up to 2600Wh/kg. The lithium air battery is also a very promising battery technology with high specific capacity, which uses the reversible reaction of lithium metal and oxygen, and the upper limit of the theoretical energy density can reach 11000Wh/kg. Second, the industry can reduce the dependence on scarce resources, For example, compared with lithium ion battery, sodium ion battery has the advantages of abundant reserves and low cost.
However, at present, innovative products of power battery are generally laboratory products, and new battery still faces many challenges in the next step of industrialization. For example, lithium sulfur battery has low safety, low volume specific energy, low discharge rate, low energy conversion efficiency and low cycle times, so it is difficult to be applied in the field of vehicles in a short time. In general, although these studies are at the experimental stage and far away from industrialization, whether they can replace existing system batteries in a certain period of time is also controversial in the industry. However, there is no doubt that these batteries are expected to break some technical bottlenecks of the current power battery, reduce battery costs, and create a longer range. In the development process of the power battery industry, these batteries cannot be ignored.
4、 Summary
From the perspective of technology development, ternary and lithium iron phosphate batteries have dominated the automotive power battery market, and ternary and lithium iron phosphate batteries have become the main technology routes of mainstream enterprises. Enterprises are further laying out these two technology routes. From the perspective of development, breakthrough has been made in ternary and lithium iron phosphate battery technology, but there is still room for further improvement in technology, which will continue for some time in the industrial competition.
From the perspective of new battery technology layout, solid state batteries have technological advantages, which can solve many problems faced by the current industry. Domestic and foreign enterprises compete for layout and have made technological breakthroughs. However, from the perspective of industrial development, solid state batteries are now in the industry accumulation period, and there are still many problems in technology and industrial support that need to be solved.
On the other hand, in addition to the improvement of current lithium batteries and the layout of solid state batteries, many research institutions are also developing new generation batteries such as lithium sulfur and lithium air batteries, and have made breakthroughs in some technologies, providing a favorable reference for the development of the battery industry. However, in general, these studies are basically in the experimental stage, far from industrialization, and there are also many disputes in the industry. However, it is undeniable that these batteries are expected to break some bottlenecks in the current power battery, which cannot be ignored in the industrial development.
While improving the performance of existing technology line products, battery enterprises should also actively layout the research and development of the next generation of batteries, so as to dominate the next round of competition. The government departments should encourage enterprises, research institutions and universities to research and develop key materials of power batteries, battery cells and key technologies of the system, and actively promote the preparation, production process The engineering and industrialization of testing and other key technologies and equipment will promote the construction of engineering technology capacity of the whole industrial chain, and promote the application of new power battery technologies and products in demonstration and promotion projects.
1. Ternary and lithium iron phosphate batteries are the focus of enterprise layout
In the field of automotive power batteries, lithium batteries have become the mainstream. At present, the main battery types of international mainstream power battery enterprises are lithium iron phosphate and ternary lithium batteries.
From the perspective of the Chinese market, lithium iron phosphate and ternary batteries are still the mainstream of automotive power batteries, accounting for 94.5% and 93.3% of the total market in 2016 and 2017.
2. Lithium iron phosphate and ternary lithium battery still have a period of development
After a period of development, the technical level of lithium iron phosphate and ternary lithium battery has been significantly improved. In terms of cost, the price of lithium iron phosphate battery pack decreased from 1.8-1.9 yuan/Wh at the beginning of 2017 to 1.45-1.55 yuan/Wh at the end of 2017. The price of ternary power battery pack dropped from 1.7-1.8 yuan/Wh at the beginning of the year to 1.4-1.5 yuan/Wh at the end of the year.
In terms of energy density, at the end of 2017, based on NCM622 material, the energy density of single battery exceeded 200Wh/kg, and the system energy density was 160Wh/kg. It is estimated that the energy density of single battery could reach 230~250Wh/kg in 2018.
These two types of batteries still have some room for improvement, especially the role of new generation materials in improving battery performance, such as the research and development of positive material 811 and silicon carbon negative electrode, which will further improve the energy density of lithium power batteries. The energy density of individual batteries is expected to reach 300Wh/kg. In addition, the two types of batteries have a strong industrial foundation, and there will be a certain period of competition in the industry.
Two、 Solid state battery becomes the focus of current layout
From the perspective of technical potential, the theoretical energy density of lithium iron phosphate system is about 170Wh/kg, and the theoretical energy density of ternary lithium battery is 300-350Wh/kg. At the same time, there are safety problems such as low thermal decomposition temperature, easy combustion and explosion, and there is relatively little room for improving the energy density of both. However, the energy density of all solid state lithium battery has great potential to be improved, which is more feasible theoretically.
1. Potential technical advantages of solid-state lithium batteries
Compared with traditional lithium batteries, solid state lithium batteries are characterized by the use of solid electrolyte materials. When the electrodes and electrolyte materials used are solid and do not contain any liquid components, they are all solid state lithium batteries. Solid state electrolyte has changed the traditional structure of lithium battery. Diaphragm, liquid electrolyte and other components are no longer necessary, bringing huge technological advantages and potential.
The main technical advantages of solid state lithium battery are as follows: first, it has high safety, does not contain flammable, volatile and toxic organic solvents, does not have leakage problems, is expected to avoid the generation of lithium dendrites, and greatly reduces the risk of battery combustion and explosion. Second, the cycle life is long, and there is no problem that the liquid electrolyte produces solid electrolyte interface facial mask during the charge discharge cycle. At present, the expected life of research and development is 15000-20000 times. Third, the energy density is high. In traditional lithium batteries, the volume of separator and electrolyte accounts for 40%. Solid electrolyte can significantly reduce the distance between positive and negative electrodes of the battery and increase the volume specific energy. The maximum potential value of energy density of all solid lithium batteries is estimated to be 900Wh/kg. Fourth, the system has high specific energy density, and the solid electrolyte has no fluidity. It can form high-voltage monomer in series, which is conducive to improving the efficiency and energy density of the power battery system. Fifth, a wide range of positive and negative electrode materials can be selected, which can simultaneously use new technologies such as lithium metal cathode and high potential cathode materials. All solid metal lithium battery is the research and development direction of new battery in the future. In addition, solid state battery has a wide working temperature range, electrochemical stability window, and has the potential of thin-film and flexibility.
2. Global enterprises have deployed solid-state batteries to compete for the first opportunity
Due to the current bottleneck of lithium iron phosphate and ternary lithium batteries and the potential advantages of solid state batteries, many enterprises in the industrial chain involving power batteries, automobiles and energy in Europe, America, Japan, South Korea, China and other countries are actively planning and developing solid state batteries.
In general, European and American countries are mainly entrepreneurial companies based on solid state battery technology, while Japan is mainly engaged in battery technology innovation based on traditional automobile enterprises and machinery enterprises. Chinese enterprises entered the field of solid state lithium battery relatively late, and were mainly supported by scientific research institutions or universities, so the industrialization process was slow.
In terms of research and development, the main force in China is the scientific research institutions of the Chinese Academy of Sciences, which has accumulated to a certain extent and is basically at the same level as foreign countries. However, there is still much room to improve the energy density from the theoretical value, and the ionic conductivity and cycle life also need to be further improved. Solid state lithium battery is divided into three technical routes according to solid electrolyte, namely polymer, oxide and sulfide solid electrolyte. The technical routes adopted by various scientific research institutions are different. Among them, Qingdao Institute of Energy of the Chinese Academy of Sciences and Institute of Chemistry of the Chinese Academy of Sciences mainly focus on polymer solid lithium batteries. The energy density of experimental samples of the former reaches 300Wh/kg, and the deep-sea test was completed for the first time. The latter broke through the bottleneck of low conductivity of polymer solid electrolyte at room temperature; The research feature of the Institute of Physics of the Chinese Academy of Sciences is to master the in-situ formation technology. The energy density of the 10Ah soft pack battery developed is 310-390Wh/kg, and the specific volume energy is 800-890Wh/L; Ningbo Institute of Materials, Chinese Academy of Sciences and Shanghai Silicate Research Institute respectively focus on the research of inorganic solid state lithium battery and composite solid state lithium battery.(Lithium - Ion Battery Equipment)
3. Technical and industrial barriers need to be broken through
Through the research of enterprises and research institutions, the solid state battery technology has made a breakthrough at present, with the energy density exceeding 300Wh/kg, but most of them are laboratory products, which is still a certain distance from industrialization.
At the technical level, ionic conductivity of solid electrolyte, solid/solid interface compatibility and stability are still two major constraints. The conductivity of polymer electrolyte is low at room temperature, and it generally needs to be heated to above 60oC to work normally. For example, Bollor é in France adopts the technical route of polymer electrolyte and battery heating; At present, the conductivity of sulfide electrolyte is equivalent to that of traditional lithium battery, but it still needs to break through the interface phase problem, mainly through material synthesis and nano layer technology to increase the amount of active substances and reduce the interface layer resistance. At the same time, lithium metal anode and new composite cathode materials are still under development, which are expected to realize the application of all solid state lithium metal batteries. At that time, there will be a huge breakthrough in energy density, capacity, multiplying performance, safety performance and cycle life.
At the level of industrialization, the difficulties of failing to achieve large-scale production mainly lie in production equipment, production process and production line environment. For example, the lamination, coating and packaging processes in the preparation of solid-state batteries need customized high-precision equipment, and the production line environment also needs to maintain a higher level of drying room. The cost of solid state lithium battery will be reduced only after the large-scale production realizes the improvement of output and capacity.
On the whole, the production and preparation maturity of solid state lithium batteries needs to be strengthened, and large-scale and automated production lines need to be further developed, which is still in the industry accumulation period. The overall development path of solid state battery is: subject to the stability of solid/solid interface, the content of liquid electrolyte gradually decreases, and the battery transits from liquid to semi-solid → solid-liquid mixture → solid to all solid state battery; In terms of the development of all solid state lithium metal battery, due to the rechargeability of lithium metal anode, the anode material will transition from graphite → alloy anode (such as Si/C) → lithium metal anode. With the development of R&D technology and industrial production, the performance and production of solid state batteries will be gradually optimized, which will usher in opportunities in the power battery market.
3、 Potential technology substitutes still exist
In addition to the improvement of current lithium batteries and the layout of solid state batteries, domestic and foreign enterprises and institutions/universities have made different attempts in power battery technology innovation. Some indicators have been greatly improved compared with the current level, providing a strong reference for the improvement of power battery performance.
Through sorting out the technical indicators of typical innovation cases collected, it can be found that the key indicators of some products have been improved. In terms of energy density, the energy density of aluminum air battery reaches 780Wh/kg, lithium sulfur battery reaches 350Wh/kg, and solid state battery reaches 360Wh/kg; In terms of charging rate, the highest charging rate of typical innovative products has exceeded 100C. In terms of cycle life, typical innovative products have been able to exceed 15000 times.
The new battery has many advantages. First, in terms of technology, for example, the lithium sulfur battery uses sulfur as the cathode material, and the theoretical specific energy of the battery can reach up to 2600Wh/kg. The lithium air battery is also a very promising battery technology with high specific capacity, which uses the reversible reaction of lithium metal and oxygen, and the upper limit of the theoretical energy density can reach 11000Wh/kg. Second, the industry can reduce the dependence on scarce resources, For example, compared with lithium ion battery, sodium ion battery has the advantages of abundant reserves and low cost.
However, at present, innovative products of power battery are generally laboratory products, and new battery still faces many challenges in the next step of industrialization. For example, lithium sulfur battery has low safety, low volume specific energy, low discharge rate, low energy conversion efficiency and low cycle times, so it is difficult to be applied in the field of vehicles in a short time. In general, although these studies are at the experimental stage and far away from industrialization, whether they can replace existing system batteries in a certain period of time is also controversial in the industry. However, there is no doubt that these batteries are expected to break some technical bottlenecks of the current power battery, reduce battery costs, and create a longer range. In the development process of the power battery industry, these batteries cannot be ignored.
4、 Summary
From the perspective of technology development, ternary and lithium iron phosphate batteries have dominated the automotive power battery market, and ternary and lithium iron phosphate batteries have become the main technology routes of mainstream enterprises. Enterprises are further laying out these two technology routes. From the perspective of development, breakthrough has been made in ternary and lithium iron phosphate battery technology, but there is still room for further improvement in technology, which will continue for some time in the industrial competition.
From the perspective of new battery technology layout, solid state batteries have technological advantages, which can solve many problems faced by the current industry. Domestic and foreign enterprises compete for layout and have made technological breakthroughs. However, from the perspective of industrial development, solid state batteries are now in the industry accumulation period, and there are still many problems in technology and industrial support that need to be solved.
On the other hand, in addition to the improvement of current lithium batteries and the layout of solid state batteries, many research institutions are also developing new generation batteries such as lithium sulfur and lithium air batteries, and have made breakthroughs in some technologies, providing a favorable reference for the development of the battery industry. However, in general, these studies are basically in the experimental stage, far from industrialization, and there are also many disputes in the industry. However, it is undeniable that these batteries are expected to break some bottlenecks in the current power battery, which cannot be ignored in the industrial development.
While improving the performance of existing technology line products, battery enterprises should also actively layout the research and development of the next generation of batteries, so as to dominate the next round of competition. The government departments should encourage enterprises, research institutions and universities to research and develop key materials of power batteries, battery cells and key technologies of the system, and actively promote the preparation, production process The engineering and industrialization of testing and other key technologies and equipment will promote the construction of engineering technology capacity of the whole industrial chain, and promote the application of new power battery technologies and products in demonstration and promotion projects.
