BATTERY PACK SOLUTIONS

Introduction

Lithium-ion (li-ion) batteries have been used commercially for over 20 years in various applications. Why then have they not been commonly adopted as batteries for single-phase UPSs? The answer lies in the fact that, like all other applications, li-ion cells weren’t available that provided UPS vendors with the right balance of price, energy density, power, safety, and reliability for single-phase UPS applications. However, advancements in li-ion chemistries and technologies over the last 10 years have provided UPS vendors with realistic options. These advancements have largely been due to requirements set forth by the electric vehicle industry.

ADVANTAGES of Li-Ion Battery UPSs among VRLA

• Fewer battery replacements (perhaps none) required over the life of the UPS eliminates the risk of downtime posed by battery replacement.
• About three times less weight for the same amount of energy.
• Up to ten times more discharge cycles depending on chemistry, technology, temperature, and depth of discharge.
• About four times less self-discharge (i.e. slow discharge of a battery while not in use).
• Four or more times faster charging, key in multiple outage scenarios.

However, li-ion batteries also have two main drawbacks compared to VRLA:

• Higher capital expenditure (capex) for the same amount of energy due to higher manufacturing cost and cost of required battery management system.
• Stricter transportation regulations.