임베디드 시스템
게재: 2009년09월04일
배터리에 관한 서베이에서 비용에 관한 항목은 예기치 않던 결과를 보여줬다. 비용이 설계 엔지니어들의 우선순위 목록 아래 쪽에 있었던 것이다. 마케팅 쪽 응답자들에게서도 거의 바닥권에 있었다. 비용 문제를 완전히 무시할 수는 없는 노릇이지만, 고객들은 배터리 성능 쪽을 핵심적인 경쟁상의 이점으로 보고 있는 것이 분명하다.
사용시간 및 용량과 관련된 배터리 성능은 시장 경쟁력의 추구에 있어서 다른 어느 것보다도 중요하다. 그에 비하면 무게, 안전성 및 비용과 같은 문제들은 설계 및 제조에 있어서 표준적 요소들이라고는 하지만 그 중요성에 있어서는 부차적일 뿐이다.
고객이 우리에게 찾아와서 주로 얘기하기 시작하는 것도 사용시간, 사이클 수명 그리고 전력과 같은 주제들이다. 엔지니어와 디자이너들은 보다 우수한 배터리 팩이 자사 제품에 경쟁적 이점을 부여할 수 있다는 사실을 너무도 잘 알고 있지만, 이들은 그 같은 팩을 어떻게 개발해야 할 지 모를 수도 있다. 이들 엔지니어와 디자이너들에게 있어서 특정 어플리케이션에 대한 정보는 무엇보다도 중요하다. 리튬이온 전지만 해도 너무도 다양한 종류들이 있으며 그 중 어느 것도 모든 어플리케이션에 적합할 수는 없다. 따라서 이러한 배터리 화학구성 방식에 대한 지속적인 교육이 필요하다.
안전성도 설계에 있어서 중요한 부분이다. 서베이에서 어떤 성능을 향상시키는 것이 최종 제품의 부가가치에 “가장 중요한지”를 물었을 때 설계 엔지니어들은 안전성을 최상위 일곱 가지 항목 가운데 두 번째로 꼽았다. 안전성에 대한 고객들의 관심도 그 어느 때보다 높아졌다. 고객들은 배터리의 화학구성 방식을 변경할 경우 그것이 안전성에 영향을 미칠 것인지를 알고 싶어한다.
스마트 배터리를 필요로 하는 어플리케이션들에 있어서 최적의 성능은 적합한 충전 회로의 설계는 물론 가장 적합한 잔여용량 측정기술과 보호 회로의 선택에 달려있다.
배터리 팩 및 충전기 제조업체들의 입장에서 볼 때 분명한 점은 이 같은 오늘날의 시장요구에 적절하게 부응해야 한다는 것이다. 따라서 이들이 배터리 기술에 대한 교육자이자 설계-제조 파트너로서의 두 가지 역할에 적극 나서지 않으면 안 된다.
By John Costa, Nexergy Inc.
Courtesy of Green SupplyLine
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.
Significance of safety
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 per cent of the design engineers and marketers were unaware of the features trade-offs 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.
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.
< Originally from 07/31/2009 >
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출처: http://www.eetkorea.com/ART_8800583119_839585_NT_92ae2e65.HTM
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