Every particle movement in a structure is an energy change but too small for us to notice. However many particle movements can involve energy changes that are substantial.
Changes of state as between, for example, solid ice, liquid water and gaseous steam happen naturally because structure particles always want an arrangement that best suits their environment.
In winter when the environment is low in energy water will become ice. As the environment warms the ice will take energy from it and use it to change its particles to the structure that is water because that structural arrangement now better suits its energy needs in the changed scene. If we now put water next to a heating element in a kettle the water changes its particle structure to that of steam because that now better suits it in its changed environment. The released steam in the now changed environment soon reverts to tiny unseen molecules of water in the air or will condense on your window or hand, if held in the path of the steam.
Changes of state are energy changes but not chemical or nuclear changes because particles are not lost, gained or shared with another structure, they are just either closer together or further apart. Chemical changes are changes that involve the loss, gain or sharing of electrons whilst nuclear changes involve the loss or gain of nuclear particles.
We do not bring about chemical or nuclear change. Particles decide when it is in their interest to make such change. What we do is provide the environment in which it suits them to make such change. Particles are always in search of a more energy efficient arrangement because it is a one in which they have most stability.
Chemicals in a battery want to rearrange their particles in more energy efficient structures. Those rearrangements involve releasing electrons at the negative terminal and taking electrons from the positive terminal. They are restricted in doing this because the terminal particles also want efficiency and stability. Connect a circuit that allows electrons to flow and the battery chemicals can start to rearrange themselves in more energy efficient ways. Particle and photon interaction energies proactively make the changes. We just create the enabling environment.
All chemical changes are energy changes. Electron energy collections can be shared by the protons of two atoms. We call it covalent bonding. Electrons can move from one atom so as to predominantly supply the energy needs of another in what is called ionic bonding. The illustration shows chlorine atoms as having taken electrons from the sodium. When discussing electricity we met metallic bonding in which electrons can’t make up their mind which to supply.
A lot of high energy holds nuclear particles together and when they decide they can find a better and more stable energy arrangement it usually involves considerable energy release.