Well, at the outset, "separable verb" and "particle verb" refer to different things. The term "separable verb" describes a syntactic (and morphological) behavioural property of the verb, whereas "particle verb" refers to a morphological process through which the verb is formed (ie: it is formed with an element of the type "particle").
On a syntactic level, it is easy to decide whether a verb that consists of an atomic element - whatever it may be - and a finite verbal element (such as EINlaufen, HEIMfahren) is separable. The verb is separable if, in a verb-second clause, the finite verbal element is placed in a fronted position and the non-finite element is stranded: Sie läuft ein, not *Sie einläuft; sie fährt heim, not *sie heimfährt. (As you probably know, separability has a range of other implications, which do not need to concern us here.)
On the other hand, whether a verb is a "particle verb" depends on the definition of "particle (verb)", which is somewhat controversial (see Elsen, Grundzüge der Morphologie des Deutschen (2nd edn 2014) 226f). Some linguists would include fixed prefixes like be- or ent- in this category. If you do that, you can readily see that the two epithets do not coincide in meaning: Sie belädt das Auto, not *Sie lädt das Auto be (ie particle verb but not separable). Some also do not consider non-finite verbal, nominal, or adjectival elements to be particles, thus they would not consider kennenlernen (which is separable: Sie lernt kennen, not *sie kennenlernt) a particle verb simply because kennen is a verb (ie separable but not a particle verb). Others, however, define the category of particle verbs along the lines of separability: If the atomic element is separable, they refer to it as a particle (-> particle verb); if it is not, they refer to it as a prefix (-> prefix verb). If you do that, then, obviously, all your particle verbs are separable by definition. One of the implications of this view is that one and the same element can be a particle or a prefix, even though the meaning of the non-finite element is virtually the same. Eg dúrchbrechen (Wiktionary) would be a particle verb, but durchbréchen (Wiktionary) would be a prefix verb. There are linguists who dislike that consequence and thus consider all elements that may be used as a separable element as particles. Again, if you do that, "particle verb" no longer guarantees separability.
An additional morphological caveat is that even if "particle verb" is defined on the basis of separability, there may, strictly speaking, still not be a bijective match between particle verb and separable verb since many would agree that verbs can also be formed by way of composition (rather than prefixation). Eg typically one would consider herunterwerfen a determinative compound (the first element has a specific stand-alone meaning, preserves that meaning, and as such specifies the content of the second) rather than the product of prefixation, so herunter would simply continue to be an adverb even within the compound. Yet herunterwefen is obviously separable: Er wirft den Ball herunter.
So, in short, the moving variable here is "particle verb". Various definitions exist. Some imply that all particle verbs are separable, some don't. I have no way of telling why you asked the question but if your interest is of a more practical nature, you should probably focus on the difference between separable and non-separable verbs. If your grammar simply dinstinguishes, as I presume many (not just) at the introductory level do, between (separable) particle and (non-separable) prefix verbs, I would just accept that and focus on the separable/non-separable part.
