Will lead carbon battery become the mainstream battery for energy storage
Lithium-ion batteries currently dominate electrochemical energy storage, but that doesn’t mean it’s the only option in the market. In addition to lead carbon battery, in recent years, new technologies such as solid-state lithium-ion batteries, metal-air batteries, and new compressed air energy storage have sprung up to suit different application scenarios and meet different functional requirements.
What is a lead carbon battery
Lead-acid batteries are one of the most widely used storage batteries. Compared with traditional lead-acid batteries, their performance indicators have been significantly improved. Lead carbon battery is called a new generation of lead-acid battery. Lead carbon battery combine lead-acid batteries and supercapacitors. It not only takes advantage of the advantages of supercapacitor instantaneous large-capacity charging, but also takes advantage of the specific energy of lead-acid batteries, and has very good charge and discharge performance in 90 minutes. full charge. Moreover, due to the addition of carbon (graphene), the sulfation of the negative electrode is prevented, which improves a factor of battery failure in the past and prolongs the battery life.
The working principle of lead carbon battery
A core problem in traditional lead-acid batteries is the sulfation of the negative electrode, that is, in the high-rate discharge mode, the spongy lead on the negative electrode reacts quickly with HSO4- to form PbSO4. At this time, because the pair of reactants HSO4- and Pb The supply mismatch of PbSO4 causes the nucleation rate of PbSO4 to be too fast, which makes the generated PbSO4 (which is insulating in nature) “paste” on the surface of the negative electrode, or generates extremely large particles; instead of what we need Uniformly generated inside the negative plate, or only fine, uniform and easy-to-reduce velvet-like PbSO4 is generated on the surface.
The PbSO2 accumulation layer or large particle PbSO2 formed on the surface significantly reduces the effective surface area and materials required for electron transfer and reaction, making subsequent reactions more difficult, thus making the interior of the negative plate a “dead” zone. When charging, because the surface PbSO2 layer hinders the body reaction of the lead-acid battery, the potential of the negative electrode at this time has to electrolyze the water in the battery into hydrogen, resulting in the depletion of the electrolyte, which will further lead to the deterioration of battery performance. In order to solve this problem, we can add carbon particles in the lead negative electrode, which will form a conductive network structure as shown in the figure above. The main advantages of this network structure are as follows.
1. Provide reaction centers: new reaction centers are formed on the surface of these carbon particles
2. Form a conductive network to reduce polarization
3. Form a smaller and uniform mass transfer network to promote the uniform progress of the electrochemical reaction on the surface and inside of the electrode, thereby reducing the concentrated precipitation effect of PbSO4 on the surface
4. As a heterogeneous material, it hinders the growth of PbSO4 particles and makes them evenly distributed
Through the capacitive effect of carbon, the capacity and power characteristics of the lead carbon battery are improved.
Based on the above advantages, the addition of carbon to the lead carbon battery can effectively suppress the sulfation trend of the negative electrode, so that the battery life is significantly improved. Not only that, the production process of lead carbon batteries is not substantially different from that of traditional lead-acid batteries. It does not need to change the mature process, and the production is easy to achieve large-scale production, especially for the long-life and low-cost requirements of energy storage batteries. For lead carbon battery, there are many types of carbon added: carbon black, activated carbon, graphene, graphite, carbon fiber, and carbon nanotubes.
And their main advantages/main functions that can be provided for lead carbon batteries are: electrical conduction and heat conduction; network pore structure, providing specific surface area required for reaction and electric double layer capacitance.
It can be said that the development of lead-carbon batteries has given the carbon material family a stage to display their talents, but how to find a balance between performance improvement and cost control may be a problem that needs attention in the application of advanced carbon materials in lead carbon battery. In addition, the addition of carbon materials also needs to be controlled. Too much carbon material will lead to a series of problems such as the falling off of the active material of the plate.
The working and performance features of lead carbon battery
The negative electrode of the lead carbon battery forms a relatively uniform and fine network of lead metal-carbon particles. This structure is conducive to shortening the diffusion distance and improving the uniformity of the reaction. Moreover, the carbon itself has good conductivity and capacitance characteristics, which makes the lead carbon battery have compared with traditional lead acid batteries, it has better low-temperature start-up ability, charge acceptance ability and high-current charge-discharge performance.
● Working with high current
The capacitor carbon material acts as a buffer. When the lead carbon battery is working under frequent instantaneous high-current charging and discharging, the carbon material with capacitive characteristics mainly releases or receives the current. At this time, the impact of the large current received by the lead metal negative electrode is small, so it will not be like the traditional lead-acid battery. Like batteries, the negative electrode sulfation occurs rapidly under high current, which effectively prolongs the service life of the battery.
● Working with low current
It is mainly operated by the sponge lead negative electrode to continuously provide energy, and the energy stored in the carbon as capacitive energy due to high current impact will also react with the lead nearby, and the reaction will gradually become uniform.
● Energy and power density
lead carbon battery can be upgraded to 40-60Wh/kg, 300-400W/kg or so, the performance is already close to the capacity of some lithium batteries, and the more critical point is that its cost is still 0.6-0.8rmb/Wh, which is lower than that of lithium batteries Batteries and other batteries have the most advantages in occasions where cost control is strict.
It has a very long cycle life under shallow charge and discharge conditions, such as 4500 times (70% DOD).
In recent years, lithium-ion batteries have developed very fast, with the introduction and improvement of lead-carbon battery technology. Its core competitiveness, low cost and good lifespan have enabled lead carbon batteries to achieve great results in the fields of stationary energy storage, low-speed electric vehicles, electric bicycles, etc., and become a strong opponent of lithium batteries and other technologies.
Advantages and disadvantages of lead carbon battery
Lead carbon battery is a capacitive lead-acid battery, which is a technology evolved from traditional lead-acid batteries. The positive active material of ordinary lead-acid batteries is lead oxide (PbO2), the negative active material is lead (Pb), and lead The carbon battery is to mix activated carbon into the negative electrode active material Pb, thus turning the ordinary lead-acid battery into a lead-carbon battery, which can significantly improve the performance and life of the lead-acid battery.
• Fast charging, 8 times faster than ordinary lead-acid batteries.
• lead carbon battery’s discharge power has been increased by 3 times.
• The cycle life is increased to 6 times, and the cycle charging times are up to 2000 times.
• High cost performance, the energy density can be increased to 40~60, the power density can reach about 300~400W/kg, and the performance is already close to the capacity of some lithium batteries. And the more critical point is that its cost is still 0.6~0.8rmb/Wh, which is lower than other batteries such as lithium batteries, and has a very good price advantage.
• lead carbon batteries can always provide reliable protection under extreme conditions such as high and low temperatures, and can still provide relatively strong power and capacity at -20°C.
• It is safe and stable to use, and can be widely used in various new energy and energy-saving fields.
• Large size and heavy weight, not suitable for mobile loads such as electric vehicles.
• Poor working efficiency at low temperature.
What are lead carbon batteries used for
◆ Stationary energy storage
In terms of stationary energy storage, energy storage fields such as photovoltaic power station energy storage, wind power energy storage, and grid peak regulation often require batteries to have the characteristics of high power density, long cycle life, and low price. Lead carbon batteries have a greater competitive advantage in occasions with ample space and high cost requirements, and relatively speaking, the initial investment cost is relatively low. Lithium batteries are more suitable for occasions that require space and are less cost-sensitive due to their high energy density and high cost, and will be more developed in distributed energy storage occasions.
Compared with other energy storage technologies, such as capacitors (very low energy storage density, which can only be used for power buffering) and the flow battery (medium technology maturity, significantly larger volume), lead carbon battery’s technology still has good competitiveness at this stage .
◆ Vehicle energy storage
In terms of transportation energy storage, the main competitive advantages of lead carbon batteries are low cost, stable performance, and good safety.
A. The low cost makes it have an advantage in the low-end market such as low-speed electric vehicles. Although the country has the idea of promoting lithium batteries, after all, market rules need to be respected.
B. Stable performance enables lead-carbon batteries to provide reliable protection under extreme conditions such as high and low temperatures. For example, the start-stop power supply of a car must be able to output a large current at -20°C, while the low-temperature performance of lithium batteries has always been a universality. long-standing problem.
C.Good safety. The safety of transportation tools cannot be overemphasized. Lithium batteries have shortcomings in this regard objectively, and the lead carbon battery have inherent advantages in this regard.
In recent years, lead carbon battery have been able to maintain their dominant position in some segments. Although technologies such as lithium batteries are growing rapidly, each of these battery technologies has its own advantages and disadvantages, and no energy storage technology can be used in various scales and scenarios. According to the needs of the field, choosing the appropriate energy storage technology application is the kingly way.
Lead-acid battery is an ancient and practical battery technology. The new generation of lead carbon battery produced by introducing the optimization of capacitor carbon has become an important booster for this amazing battery technology to continue its legend in the new era. Cost, performance stability, and safety are the core advantages of this type of battery. Therefore, it will still have good competitiveness in the fields of stationary energy storage and low-end electric vehicles in recent years. Of course, with the continuous advancement of various technologies, we also earnestly hope that more newer and better energy storage technologies will continue to emerge and mature, thereby bringing convenience to our lives.