EFB Car Battery Guide- Everything You Need to Know About EFB Technology

EFB Car Battery
EFB Car Battery

Motor vehicles come with start and stop systems that are designed to make fuel economy better in nowadays. The start and stop system does so by limiting the engines idle time, which made possible by shutting down and restarting the engine’s internal process subsequently. Therefore, it is necessary to have a car battery with improved deep cycle durability for a reduced charge state. It is normal with start and stop systems. Most of the motorists would assume a typical flooded battery would suffice. However, it is not the case. An EFB car battery is required. 

If you don’t know what this technology entails, keep reading. You will learn about the different battery technologies as well as the features making EFB car battery special.

What is an EFB car battery?

An EFB car battery is an enhanced flooded battery, which can also be used in cars that feature start and stop technology. It is considered as an entry level battery for use in cars with this technology. EFB car battery is wet-filled and similar to standard flooded battery, but there are differences that give EFB battery improved charge acceptance and enhanced cycling abilities. It means the battery recovers more quickly, as its application needs to handle heavy-duty, cyclic, start and stop applications. EFB car battery is an enhanced version of standard wet-flooded technology. The primary benefits of EFB technology are greater cyclic durability and improved charge acceptance when operating in a reduced state of charge, especially of stat and stop applications.

Approximately, Compared to 30,000 starts from standard flooded product, EFB car battery will provide 85,000 engine starts.

Spaceflight EFB Battery (1)

(EFB start and stop battery)

Comparison among SLI, EFB battery and AGM battery

The flooded SLI battery is designed should have low cost but is not suitable for regular deeper cycling and deliver short-time high power discharges. While, the standard flooded battery cannot fulfill the demand of the micro-HEV when regenerative braking during using. The AGM battery is better suited for the micro-HEV application as it provides much longer lifetime and more consistent DCA. Problems with sulfation during PSoC operation can be reduced by the incorporation of carbon additives on the negative plate. The gel battery has such a long cycle life. However, the power capability is too low for the cold cranking function. Spiral-wound AGM battery provides high power together with remarkable cycle life at manufacturing cost significantly above those of prismatic AGM battery. Neither the Gel battery nor the spiral-wound AGM battery has yet been used in micro-HEVs. Spiral-wound AGM batteries may, but it may be considered as candidate for applications with extreme demands toward both power and cycling, for example, mild hybrid traction battery.  AGM car battery is about 1.5 to 2 times more expensive than the flooded SLI battery of cranking performance and identical capacity. Therefore, EFB car battery has been developed with deep cycle life below the AGM battery values but similar shallow cycling performance and durability and at distinctly lower cost, which is of only 20% to 40% above their conventional flooded counterparts.

AGM Start and Stop Battery (2)

(AGM start and stop battery)

EFB design strategy

Higher positive paste density for longer cycle life, however, in the same time, the pore structure must be optimized to maintain the cold cranking performance. Use nonwoven scrim on the positive or both electrodes, which replaces the pasting paper in continuous platemaking processes, to further enhance cycle life as well as reducing electrolyte stratification. Additives, but mostly carbon, of the negative active mass reduce PSoC problems. Thinner plates and optimized grid structure together with more electrodes each cell block that minimize internal resistance so that improving both and DCA and voltage quality during automated restart.

With these improvements, some EFB battery designs have demonstrated to achieve almost equivalent cycle life as AGM battery at similarly high battery weight that is about 2kg to 3 kg above SLI battery. However, significantly lower cost. Other car manufacturers and original equipment manufacturers have focused on weight-optimized EFB designs, which are good enough for shallow cycling demands of micro-hybrid vehicles. Firstly, it is in Japan, then more recently in Europe. Carbon additives have been used to allow further weight reduction at identical micro-hybrid service life. Several years after broad market introduction of micro-hybrid technology, It is obviously that AGM battery will be mostly restricted to premium car or commercial vehicle applications that add significant deeper cycling requirements to the micro-hybrid duty cycle, but the different grades of EFB can satisfy the majority of mass-market micro-hybrid needs.

The DCA of most EFBs and AGM car batteries surpasses the acceptance criteria of the draft EN 50342-6 standard, but further improvement of DCA remains a challenge for the reason that improving real-world fuel economy, it also avoids undercharge issues in modern power supply systems with ever more demanding transient loads.

It is necessary for my car need an EFB car battery?

Your car will only require an EFB car battery if it currently has one. For example, vehicles with start and stop technology may use one kind of start and stop batteries. Both AGM and EFB car batteries are designed for the frequent cycling required when a vehicle is equipped with start and stop system. Vehicle owners new to the start and stop feature may be concerned about the impacts of it on the battery, but battery required for this technology to function correctly are built to tolerate constant stopping and starting. It is as well as why replacing your battery with the correct type is essential to maintaining its performance.


More and more cars in nowadays are equipped with start and system, so EFB car battery and AGM car battery is in more need. EFB car battery is also the more popular option for the cars in the future, which has many advantages. Such as less shedding of active-material, reducing acid stratification, increasing deep and partial cycling capability, enhancing negative-plate performance via addition of extra carbon and/or other additives, improving grid alloys and structures and protection of negative lugs against corrosion, and of higher lead use.

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