Electrode assembly structure, secondary battery, and methods of manufacture
A method for manufacturing a structure comprising and electrode assembly having a porous electrically insulating material, and first and second endplates, is provided. The electrode assembly comprises a population of unit cells stacked in series in a stacking direction, opposing first and second longitudinal end surfaces separated along the stacking direction. First and second endplates are separated in the stacking direction and overlie the first and second longitudinal end surfaces. According to embodiments of the structure, (i) each unit cell comprises an electrode structure, a counter-electrode structure, and an electrically insulating separator between the electrode and counter-electrode structures, (ii) the electrode structures, counter-electrode structures and electrically insulating separators within each unit cell have opposing first and second vertical end surfaces separated in a vertical direction, and (iii) the vertical direction is orthogonal to the stacking direction. The method comprises providing a porous electrically insulating material to the electrode assembly using a stencil.
1. A structure for energy storage, the structure comprising an electrode assembly, a first endplate opposing, and separated from, a second endplate, the electrode assembly comprising:
(a) an electrically insulating material;
(b) a population of unit cells stacked along a stacking direction, unit cells of the population of unit cells being electrically coupled with each other in series, the stacking direction opposing, or in a direction of, a longitudinal direction, the population of unit cells having a first longitudinal end surface opposing to, and separated from, a second longitudinal end surface, the first longitudinal end surface and the second longitudinal end surface being stacked along the stacking direction, the first endplate and the second endplate being stacked along the stacking direction, the first endplate vertically overlapping the first longitudinal end surface, the second endplate vertically overlapping the second longitudinal end surface,
each unit cell of the population of unit cells comprising an electrode structure separated from a counter-electrode structure, and a separator comprising the electrically insulating material disposed between the electrode structure and the counter-electrode structure, the electrode structure, the counter-electrode structure, and the separator, each having a first end surface opposing to, and vertically separated from, a second end surfaces, a vertical direction being orthogonal to the stacking direction, an endplate comprising a vertical thickness along the vertical direction and an inner portion coupled with opposing outer portions separated vertically along the endplate,
the first endplate comprising a first vertical thickness having a first maximum thickness and a first inner portion coupled with opposing first outer portions separated vertically along the first endplate, a vertical thickness of the first inner portion (i) being greater than a vertical thickness of any of the first outer portions and (ii) coinciding with the first maximum thickness, the second endplate comprising a second vertical thickness having a second maximum thickness and a second inner portion coupled with opposing second outer portions separated vertically along the second endplate, a vertical thickness of the second inner portion (iii) being greater than a vertical thickness of any of the second outer portions and (iv) coinciding with the second maximum thickness; and
(c) a porous electrically insulating material at least partially covering the first longitudinal end surface and/or the second longitudinal end surface, the porous electrically insulating material being configured to allow transit of carrier ions therethrough to the first end surface and to the second end surface.
2. The structure of claim 1 , wherein the stacking direction is along a stacking axis, the structure further comprising a constraint system coupled with the population of unit cells at opposing sides of the population of unit cells, the opposing sides being along an axis normal to the stacking axis.
3. The structure of claim 2 , wherein the constraint system comprises apertures.
4. The structure of claim 3 , wherein an aperture opening has a long axis disposed along the stacking direction, the aperture opening being of the apertures.
5. The structure of claim 3 , wherein the apertures are evenly spaced along a portion of the constraint system.
6. The structure of claim 3 , wherein the constraint system comprises a set of opposing constraints.
7. The structure of claim 6 , wherein the opposing constraints of the set of opposing constraints are separated from each other by a gap.
8. The structure of claim 3 , wherein the constraint system is configured to restrict endplates from separating from the constraint system and away from the population of unit cells, the endplates comprising the first endplate or the second endplate.
9. The structure of claim 3 , wherein the constraint system is configured to restrict the first endplate and the second endplate from separating from the constraint system and away from the population of unit cells, when the population of unit cells are under compressive pressure.
10. The structure of claim 3 , wherein the constraint system comprises at least one aperture through which the porous electrically insulating material is visible.
11. The structure of claim 2 , wherein the constraint system comprises at least one aperture having an oblong shaped lateral cross section.
12. The structure of claim 1 , wherein the porous electrically insulating material is configured to allow transit of carrier ions therethrough.
13. The structure of claim 1 , wherein the porous electrically insulating material is configured to allow transfer of the carrier ions to replenish the carrier ions in the electrode assembly during an initial formation process and/or during cycling between charged and discharged states.
14. The structure of claim 13 , wherein the porous electrically insulating material is configured to allow transfer of the carrier ions to replenish the carrier ions in the electrode assembly during an initial formation process.
15. The structure of claim 1 , further comprising bumpers configured to adjust compressive pressure in the structure.
16. The structure of claim 1 , wherein the porous electrically insulating material comprises a ceramic.
17. The structure of claim 1 , wherein the porous electrically insulating material comprises a polymer.
18. The structure of claim 1 , wherein the electrode structure comprises a current collector folded along the stacking direction to connect with an electrode busbar.
19. The structure of claim 18 , wherein the electrode structure comprises a current collector folded towards the stacking direction to connect with an electrode busbar.
20. The structure of claim 18 , wherein each unit cell of the population of the unit cells comprises the electrode structure comprising the current collector folded towards the stacking direction to connect with the electrode busbar.