When our customers approach us about battery reliability, the most pressing question is always, “How do we prevent catastrophic battery failures?” While the rate of field failures is statistically low at only 1 to 10 ppm, the impact of battery failures has often been severe in recent years. Higher energy densities, and the use of lithium ion batteries closer to the human body are to blame for the severity of impact.
It takes only a few seconds to search for “battery explosions” and receive scores of news stories about consumers getting injured as a result of battery explosions. In the last year, two people have lost their lives due to E-cigarette battery explosions.
The increasing concern around lithium-ion batteries and the need for companies to have a risk mitigation strategy is therefore understandable. Changes in the supplier landscape have also increased the risk for companies that make battery powered products.
The battery supply chain has changed in the following ways:
- Growing Pool of Smaller Battery Manufacturers
The growing pool of battery manufacturers is one market trend that is contributing to faulty batteries. Historically, battery production which was based in Japan, has expanded to other Asian countries to keep up with the growing demand for lithium-ion batteries. This has produced an influx of small manufacturers, some with very questionable quality practices, resulting in higher risks for companies that use batteries in their products
- Loss of Tier 1 Suppliers to the Automotive Space
The growing demand for lithium-ion batteries in the automotive space, means that Tier 1 companies that supplied 18650 cells have shifted focus away from consumer applications. Product companies with small to medium manufacturing volumes that could rely on a Tier 1 supplier before, are now forced to move to a lower Tier supplier due to supply shortages. The onus of requalifying these new suppliers has fallen back on the product companies.
- Increasing Use of Pouch Cells
Another market trend is the increased utilization of pouch cells ,due to their increased form factor flexibility and the ability to produce sleek looking products. As a result, many of the safety issues that arise in lithium ion batteries have shifted from the cell to the integration of the battery and how designers build their product. If products are designed so as to put mechanical stress on pouch cells and without sufficient mechanical tolerances, the risk of catastrophic failure is increased. .
- Higher Energy Densities & Closer to the Body
There has been a push for higher energy densities as electronic products become increasingly universally integrated with our daily lives. Consumers carry products such as cell phones, e-cigs, and smart watches on their person at all times. Meanwhile, battery manufacturers are packing more active material yet using thinner separators to bump up energy density. That means the tolerance for manufacturing defects, like having small metallic contamination, is decreased even more. It’s a formula for risk: lower tolerance for manufacturing defects coupled with an increase in energy density and closer proximity to the body. Given the daily reliance consumers place on electronic products, the occurrence of catastrophic failures has risen organically before even considering possible defects.
- Companies without Battery Core Competency
Large corporations that see batteries as a core competency, have in-house battery divisions and manufacturing. However, with the growing market demand of IoT devices and the push to provide better performing products, companies whose core competency is not batteries, have also had to use lithium-ion batteries. These companies now own the cradle to grave lifecycle of the lithium -ion battery they use, and must respect its narrow operating window. This is true not only for manufacturing but for battery storage, warehousing, transportation, use, application integration, and even the final disposal.
Lack of internal battery expertise may put companies at risk in managing the battery lifecycle. Examples include cell swelling or thermal events due to cells going into deep discharge from improper storage conditions. Another example is the risk of recycle trucks catching on fire due to lack of guidance to consumers on lithium-ion battery disposal.
The battery supply chain has changed over the past couple of decades, and that puts companies using batteries at elevated risk.
While the market conditions listed above have made it difficult for designers to eliminate catastrophic failures, having an awareness of those trends can allow designers to make more informed decisions about battery safety, selection, qualification and integration. The results can not only lead to better business practices, but also create safer products for consumers.
Interested in learning more about Lithium-Ion batteries? Check out our webinar Why Lithium-Ion Batteries Fail by clicking the link below.