With the increasing popularity of electric vehicles in recent years, safety issues have become a major concern for consumers.
In November of last year, General Motors announced a recall of Chevrolet Bolt electric vehicles manufactured between 2017 and 2019, primarily due to at least five fire incidents involving this model worldwide, all of which were equipped with batteries manufactured by South Korea's LG Chem.
In terms of market structure, the global battery usage for electric vehicles (EVs, PHEVs, HEVs) is basically monopolized by China, Japan, and South Korea. As of September 2020, the three major South Korean battery companies—LG Chem, Samsung SDI, and SK—held a global market share of 35.1%.
Data shows that from January to September 2020, LG Chem's global market share in electric vehicle batteries increased to 24.6%, ranking first in the world. Currently, LG Chem's batteries are the most widely used batteries in electric vehicles sold globally, and the company's customers include 13 well-known global automakers such as Hyundai, Volkswagen, and Volvo.
In October 2020, Hyundai Motor also recalled a large number of its KONA electric vehicles that used LG Chem batteries due to potential battery fire hazards. In addition to LG batteries, in the first half of this year, approximately 50,000 electric vehicles from BMW and Ford that used Samsung SDI batteries were also recalled due to fire incidents, pushing the quality issues of South Korean battery companies to the forefront of public opinion.
Types of automotive power batteries
Currently, the mainstream types of batteries for new energy electric vehicles on the market can be roughly classified into several categories, including lead-acid batteries, nickel-metal hydride batteries, lithium cobalt oxide batteries, lithium manganese oxide batteries, lithium iron phosphate batteries, and ternary lithium batteries (nickel-cobalt-manganese lithium oxide batteries).
lead-acid batteries
Low cost, good low-temperature performance, and high cost-effectiveness; however, low energy density, short lifespan, large size, and poor safety. Due to its low energy density and lifespan, electric vehicles powered by it cannot achieve good speeds and long driving ranges, and are generally used in low-speed vehicles.
Nickel-metal hydride batteries
Low cost, mature technology, long lifespan, and durability; however, low energy density, large size, low voltage, and battery memory effect. Due to its superior durability, it has been used in Toyota's Prius hybrid model for a long time. Compared to lithium batteries, the voltage of a single nickel-metal hydride battery cell is only 1.2V, one-third that of lithium batteries. Therefore, for a given voltage requirement, nickel-metal hydride batteries are significantly larger than lithium batteries. Although its performance is superior to lead-acid batteries, it contains heavy metals and causes environmental pollution when disposed of.
Lithium-ion batteries
It is one of the most technologically advanced batteries currently available. This type of battery has high energy density, meaning it can store a lot of electricity; it also has a long cycle life, meaning it can be charged and discharged many times and lasts for a long time. Currently, the lithium batteries used in electric vehicles are mainly of two types: lithium iron phosphate batteries and ternary lithium batteries. Simply put, "lithium iron phosphate" and "ternary lithium" are both positive electrode materials in power batteries, playing a decisive role in the battery's energy density. Therefore, battery naming conventions often use the positive electrode material, as is the case with ternary lithium batteries and lithium iron phosphate batteries.
In a few years, we'll see the emergence of solid-state lithium-ion batteries. Solid-state lithium batteries use a solid electrolyte instead of a liquid one, resulting in large capacity, fast charging, and no risk of electrolyte leakage and fire—making them ideal power batteries. Several companies worldwide have already launched prototype solid-state batteries, and perhaps within three to five years, this type of battery will emerge as a major player.
Despite significant advancements in lithium battery technology, substantial safety hazards remain. The primary cause of fires in new energy electric vehicles lies in the power battery. Completely eliminating this hazard is a long road ahead for the lithium battery industry. Furthermore, once a lithium battery catches fire, it is extremely difficult to extinguish, easily triggering a chain reaction and posing a significant threat to our lives. Therefore, we should consider detecting fires as early as possible and nipping them in the bud to minimize losses.
Lithium batteries typically produce a large amount of CO before catching fire, making CO concentration monitoring an effective solution. However, this approach usually requires high sensitivity and reliability from the CO sensor. Here, we recommend the reliable carbon monoxide sensor TGS5042, which boasts high sensitivity, good reliability, and long lifespan, making it ideal for lithium battery fire detection.
As we all know, new energy vehicles are the future trend, and any automaker that wants to achieve long-term development must master its own new energy vehicle technology. Currently, domestic power battery companies are also trying to enhance their competitive advantage and expand their market share through technological upgrades and product iterations.
However, new energy vehicles are very different from traditional fuel vehicles. The key to the development of new energy vehicles is battery technology. Whoever masters the automotive battery technology will have a proactive advantage in the era of new energy vehicles.
