The Lightning Network is a layer-2 payment protocol built on top of the Bitcoin blockchain that aims to address some of the scalability issues of the Bitcoin network. The Lightning Network allows for fast and cheap transactions between two parties without the need for every transaction to be recorded on the blockchain.

A fundamental building block of the Lightning Network is the payment channel. Payment channels enable users to transact with each other without broadcasting every transaction to the blockchain, which can otherwise be slow and expensive.

A Lightning Network payment channel is a two-way connection between two parties that enables them to exchange funds. To open a channel, the parties create a multi-signature Bitcoin address. 

Once the payment channel is open, the parties can exchange funds by creating and signing off on transactions that update the balance of the channel. The Lightning protocol requires both parties to sign off on any transactions within the channel. Suppose Party A and Party B open a Lightning Network channel with an initial balance of 1 Bitcoin each. In that case, party A can send Party B 0.5 Bitcoin by creating a new transaction that updates the channel balance to 1.5 Bitcoin for Party B and 0.5 Bitcoin for Party A, which each of them sign. This transaction is not broadcasted to the blockchain and is only recorded in the channel's off-chain state.

The Lightning Network payment channel remains open until either party decides to close it. When the channel is closed, the final state of the channel is recorded on the Bitcoin blockchain, which enables the parties to claim the funds  to which they are entitled. If one party tries to cheat by broadcasting an outdated transaction, the other party can use the most recent transaction to claim the funds, and any penalty they are owed.

Lightning Network channels can be used to make multiple transactions between the channel counter parties without having to broadcast each transaction to the Bitcoin blockchain. This can significantly reduce transaction fees and increase the speed of transactions.

Another benefit of Lightning Network channels is that they can be used to make small payments. Once a channel is established, small payments can be cost-effective.

There are some potential drawbacks to using Lightning Network channels. One is that opening and closing a channel, which involve transactions on the Bitcoin blockchain,  can take time and incur transaction fees, so it may not be ideal for one-time or infrequent transactions.  Also if one party goes offline, the other party has to wait to close the channel either by forcing a close or waiting for the channel to come back online. 

In conclusion, a Lightning Network payment channel is a two-way connection between two parties that enables them to exchange funds without broadcasting every transaction to the Bitcoin blockchain. While Lightning Network channels may not be an ideal solution for all use cases, they offer a promising solution to the scalability issues of the Bitcoin network. They can significantly reduce transaction fees and increase the speed of transactions.  Companies - like Lightspark - are building enterprise-ready infrastructure to address the drawbacks, which will result in greater adoption of businesses using the Lightning Network.