where is the battery located is the question? it is different for many different barbecues. Often the button unscrews to allow access to a AA or AAA battery. Also some grills that use a 9-volt mount it just below the button under the control panel. In a DCS the drip pan must be removed, n a solaire or alfresco the dors must be opened to expose the 9-volt. On a lynx the battery is inside a compartment on the right and left side of the control panel. Many newer grills are using transformers instead of these batteries and last year FireMagic released a grill that had a solar panel that replaced the batteries.
I hope this helps but if not let me know what brand of bbq you have so I can tell you more exactly where the battery is located.