Is it normal for the power bank battery color to be purple? I heard that blue color is normal

Does the subject of the question exist? If it is just the outer packaging of the rechargeable battery, there is nothing, because the outer packaging of the battery can be of any color and is mainly used to prevent rust and 'insulation. But if it's the battery case, it's different. , because the battery case is made of stainless steel. Generally, a battery is considered normal if the battery case has no rust, leaks, or bulges. Today's 18650 lithium rechargeable batteries are the best from the Japanese manufacturer Sanyo. Of course, they are expensive. Home batteries are the common batteries for most power banks. In addition, power bank batteries are also different from soft-packaged lithium polymer batteries and 18650 batteries. Different batteries Outer packaging colors varyfrom one manufacturer to another!