Apple has published on the site, to the section on support for the iPad, that in cases of defective iPad battery, will be replaced with new battery for charge of $99! (Plus shipping).
In particular if the iPad need service due to reduced capacity of the battery to maintain electrical charge, Apple will replace it with a charge for this service.
Of course not covered by iPad which have been damaged by the user, such as drop, penetration of liquids, disassembly, unauthorized service and modifications, or if the product does not work properly because of a flaw in another part.
The price for this service replacement is $99 plus $6.95 for shipping costs (U.S.), so the total cost amounts to $105.95 for each iPad.
The Apple does not undertake to preserve the data in the defective battery iPad, so advises users to synchronize the iPad with iTunes to keep their data before it get corrupted.
The replacement process will be calling Apple Technical Support Section and will be completed within a week (always speaking for the U.S.)
The full text is from the site of Apple is as follows:
Battery Replacement Service - iPad: Frequently Asked Questions What is iPad Battery Replacement Service? If your iPad requires service due to the battery's diminished ability to hold an electrical charge, Apple will replace your iPad for a service fee. Note: Your iPad is not eligible for Battery Replacement Service if the product has been damaged, for example, as result of an accident, liquid contact, disassembly, unauthorized service or unauthorized modifications, or if the product is not operating correctly as a result of a component failure. Please review Apple's Repair Terms and Conditions for further details. How much does it cost? The service costs $ 99, plus $ 6.95 shipping. The total cost is $ 105.95 per unit. All fees are in US dollars and are subject to local tax. How do I arrange iPad Battery Replacement Service? Battery replacement service may be arranged via your local Apple Retail Store or Apple Authorized Service Provider, or you can contact Apple Technical Support. Please do not send any accessories with your iPad. Will the data on my iPad be preserved? No. You will receive a replacement iPad that will not contain any of your personal data.Before you submit your iPad for service, it is important to sync your iPad with iTunes to back up your contacts, calendars, email account settings, bookmarks, apps, etc. Apple is not responsible for the loss of information when servicing your iPad. How long will it take to receive my replacement iPad? If you arrange service by calling Apple Technical Support, you can expect service to be completed within approximately one week from the time you send your iPad to Apple.