Conformal wearable battery
A battery system includes a plurality of non-cylindrical shaped battery cells arranged on, and physically affixed to, a flexible printed circuit board (PCB). The PCB may include a bend axis that facilitates folding of the flexible PCB to form an upper portion of the flexible PCB and a lower portion of the flexible PCB. A central stiffener may be positioned between the upper portion and the lower portion of the flexible PCB using an adhesive foam tape to form a battery assembly. The battery system may include a flexible housing with an internal cavity that receives the battery assembly. The central stiffener, and the adhesive foam tape, may provide a degree of rigidity and/or absorption to the PCB to reduce localized deformation of the PCB when the battery system experiences shock forces and to prevent damage to components of the battery assembly. The stiffener may be formed from non-metallic material.
1. A conformal wearable battery comprising:
a plurality of battery cells; and
a folded flexible printed circuit board (PCB) comprising:
a plurality of physical connection sections disposed in a grid like pattern, wherein each battery cells of the plurality of battery cells is affixed to the folded flexible PCB; and
a bend axis that delineates an upper portion of the folded flexible PCB and a lower portion of the folded flexible PCB;
a central stiffener positioned between and affixed to the upper portion of the folded flexible PCB and the lower portion of the folded flexible PCB, the central stiffener comprising a non-metallic material with a flexural strength within a range of 410 MPa and 560 MPa; and
a flexible housing that receives the plurality of battery cells, the folded flexible PCB, and the central stiffener.
2. The conformal wearable battery of claim 1 , wherein the central stiffener comprises a glass filled composite.
3. The conformal wearable battery of claim 1 , wherein the central stiffener comprises a polycarbonate material.
4. The conformal wearable battery of claim 1 , wherein the central stiffener has a thickness within a range of 0.13 millimeters and 0.38 millimeters.
5. The conformal wearable battery of claim 1 , wherein the central stiffener includes a corner that extends beyond a corresponding corner of the folded flexible PCB.
6. The conformal wearable battery of claim 5 , wherein the corner of the central stiffener comprises a protrusion that extends beyond a lower edge of the central stiffener.
7. The conformal wearable battery of claim 6 , further comprising a corner bumper adjacent to a corner of the folded flexible PCB, wherein the corner bumper includes a notch that receives the protrusion of the central stiffener.
8. The conformal wearable battery of claim 1 , wherein the central stiffener has an elastic modulus within a range of 2.0 GPa and 15 GPa.
9. The conformal wearable battery of claim 1 , wherein the central stiffener is affixed to the upper portion of the folded flexible PCB with a first adhesive tape and is secured to the lower portion of the flexible PCB with a second adhesive tape, wherein the first adhesive tape has a different thickness than the second adhesive tape.
10. The conformal wearable battery of claim 1 , wherein the central stiffener includes an aperture that extends through the central stiffener, wherein the aperture of the central stiffener comprises a plurality of apertures that are arranged in a pattern of rows and columns.
11. The conformal wearable battery of claim 1 , wherein the non-metallic material has an ultimate tensile strength within a range of 69 MPa and 276 MPa.
12. The conformal wearable battery of claim 1 , wherein the central stiffener includes a hole near an upper corner of the central stiffener to connect to a connector stabilizer on at least one side of the folded flexible PCB, wherein a fastener is received in a hole of the central stiffener and a hole in the connector stabilizer.
13. A conformal wearable battery comprising:
a battery cell core pack assembly comprising:
a folded flexible printed circuit board (PCB), wherein a bend axis that delineates an upper portion of the flexible PCB and a lower portion of the flexible PCB;
a plurality of battery cells affixed to the flexible PCB; and
a non-metallic central stiffener positioned between the upper portion of the folded flexible PCB and the lower portion of the folded flexible PCB preventing the upper portion from contacting the lower portion, wherein a corner of the central stiffener extends beyond a corresponding corner of the upper portion or the lower portion of the flexible PCB; and
a housing that includes an upper housing member, a lower housing member, and an internal cavity, wherein the internal cavity receives the battery cell core pack assembly.
14. The conformal wearable battery of claim 13 , wherein the central stiffener is secured to the upper portion of the flexible PCB with a first adhesive tape having a first tape thickness and is secured to the lower portion of the flexible PCB with a second adhesive tape having a second tape thickness, and
wherein the first tape thickness is different than the second tape thickness.
15. The conformal wearable battery of claim 14 , wherein the second adhesive tape comprises a foam tape, and wherein the second tape thickness is greater than the first tape thickness.
16. The conformal wearable battery of claim 13 , wherein the central stiffener has a thickness within a range of 0.13 millimeters and 0.38 millimeters.
17. The conformal wearable battery of claim 13 , wherein the central stiffener has an elastic modulus within a range of 2.0 GPa and 15 GPa.
18. The conformal wearable battery of claim 13 , wherein the central stiffener has a weight within a range of 6 grams and 20 grams.
19. A system comprising:
a battery cell core pack assembly comprising:
a folded flexible printed circuit board (PCB), wherein a bend axis that delineates an upper portion of the folded flexible PCB and a lower portion of the folded flexible PCB;
a plurality of battery cells affixed to the flexible PCB, wherein each battery cell of the plurality of battery cells is a pouch cell type battery; and
a central stiffener positioned and affixed between the upper portion and the lower portion of the flexible PCB preventing the upper portion from contacting the lower portion, the central stiffener having a corner that extends beyond a corresponding corner of the flexible PCB,
wherein the central stiffener comprises a glass filled composite and is secured to the upper portion of the folded flexible PCB with a first adhesive tape and is secured to the lower portion of the folded flexible PCB with a second adhesive tape, and
wherein the first adhesive tape has a different thickness than the second adhesive tape; and
a housing that includes an internal cavity, wherein the internal cavity receives the battery cell core pack assembly.
20. The system of claim 19 , wherein the corner of the central stiffener comprises of a protrusion that extends beyond a lower edge of the central stiffener.