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Scan the horizon of the battery technology market today. You'll see prominent technological landmarks familiar to everyone from the medical device designer to the commercial-off-the-shelf customer. Battery performance, as it relates to runtime and capacity, guides all of our journeys in search of market advantage. Such issues as weight, safety and cost—though obviously standard factors in design and manufacture—remain in a secondary position.
Numerous battery chemistries can be found on that horizon as well, from conventional lithium-ion to lithium-iron-phosphate to high-rate lithium-polymer. For a significant number of people in the industry, those many chemistries have created a sense of disorientation. Which chemistry will serve my product best? Which will help me gain market leadership? In a recent survey conducted by Nexergy, Inc., about a third of the design engineers and marketers interviewed were unable to identify their choice for their next portable power solution.
A desire for optimal battery performance and a knowledge gap regarding chemistries exist side by side in a market in which the majority of engineers consider battery pack performance as a key competitive advantage for products. Greater market education is an obvious long-term solution. Possibly less obvious is the design engineers' understanding that partnering with seasoned experts can help ensure competitive advantage today and in the future.
When the customer "walks through the door," the typical discussion begins with the topics of runtime, cycle life, and power. Engineers and designers are indeed confident that the better battery pack can create a competitive advantage for their products—but they may not know how to create that pack. For those engineers and designers, application-specific information becomes critical. Many questions need to be answered, including:
•How long must the device run between full charges?
•How much space and weight can be allocated to the power source?
•What is the load consumption of the device during operation or standby if typical applications include long periods of inactivity between uses?
•What are the minimum and maximum values for supply voltage?
•What is the pack output needed to meet the product's peak load or continuous current requirements?
•What is the acceptable battery life in the typical usage scenario?
With applications requiring a smart battery, optimal performance will also depend on the selection of the most appropriate gas-gauging technology and protection circuitry as well as the designing of the correct charge circuit, regardless of whether it is internal or external to the pack. Feedback from our study confirmed that the industry is coming to appreciate these aspects of the design challenge. Ensuring that the gas gauge is accurate, or that the charge or discharge cycles don't terminate prematurely or that the pack is not abusively charged or over-discharged affects realized capacity, safety and cycle life.
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Safety is a significant part of a design matrix. When respondents were asked about which performance improvements are "most critical" to adding value to the end product, design engineers ranked safety as number two out of a seven-choice ranking in which one is most critical and seven least. Marketers listed safety right in the middle of this ranking. Safety is on customers' minds more than ever. That's always a big question during our customer meetings. Customers want to know if a change in battery chemistry will affect safety.
As far as cost is concerned, our survey delivered an unexpected result. Cost appeared low on the priority list for design engineers, and nearly at the bottom among our marketing contacts. Cost can never be totally discounted, but battery performance is clearly seen by our customers as the core competitive advantage.
The underpinnings of the core competitive advantage lie in the battery chemistries themselves. That fact again underscores the need for continuing education about those chemistries. Take lithium-ion iron-phosphate (LiFePO4) as one example. More than 40 percent of the design engineers and marketers were unaware of the features tradeoffs with this chemistry. They didn't know that LiFePO4 offers excellent cycle life, high rate capability and a high level of safety. At the same time, this chemistry has lower energy density compared with conventional lithium-ion.
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The fact is that there are so many different variants of lithium-ion cells, not every one fits every application. Some are better suited to high temperature; some to low temperature; some are ideal for supporting higher discharge rates. The key element is to understand all the different cell chemistries available and to select the right one that delivers the longest runtime and overall performance while taking into account the application's other requirements such as size, cost and weight.
Beyond the issue of battery chemistry, we learned that there is confusion with regard to the shipping of lithium batteries, which can become a key factor in weighing pros and cons of battery chemistry choices. Nearly half of the design engineers Nexergy had contacted for our recent survey admitted that they were "not very aware" of the new DOT shipping regulations.
For the manufacturers of battery packs and chargers, the challenge of serving today's market appropriately is clear. We must step into the dual role of educator and design-manufacturing partner. The companies best prepared to take on this role are companies with expertise across chemistries, from sealed lead-acid to lithium-ion to new and emerging chemistries such as lithium-ion iron-phosphate.
In summary, proper cell selection and battery electronics can indeed create the competitive advantage for a manufacturer that seeks a portable power solution. An alliance with an expert in portable power design, integration, and manufacturing can ensure it.
About the author
John Costa joined Electritek AVT in June of 1999 as a Vice President, Battery Charger Group. He was responsible for their battery charger business development until 2002, when he was promoted to the position of Chief Operating Officer. With the merger of Electritek AVT and Nexergy (Columbus, Ohio) this year, John has assumed the position of Executive Vice President of the new company and heads up their New Business Development Center responsible for sales, marketing, and product development.
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