Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present disclosure relates a foam pad and a battery pack comprising the foam pad.

Background of the invention:
[0002] A patent literature US2021194041 discloses pressure regulation system for silicon dominant anode lithium-ion cell. The disclosure herein pertains to a pressure regulation system for use in a silicon dominate anode lithium-ion cell. The pressure regulation system regulates a lifetime pressure on the lithium-ion cell in order to correct for capacity loss and mechanical failure due the expansion of silicon during operation. The pressure regulation system along with a housing maintains a certain pressure range on the lithium-ion cells during the cycling and the operational life of the energy storage device.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0004] Fig. 1 illustrates a stack of pouch cells and an enclosure of battery pack, according to an embodiment of the present invention;
[0005] Fig. 2 illustrates types of foam pads, according to an embodiment of the present invention;
[0006] Fig. 3 illustrates the foam pad, according to an embodiment of the present invention, and
[0007] Fig. 4 illustrates a method for anodizing the enclosure of the battery pack, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0008] Fig. 1 illustrates a stack of pouch cells and an enclosure of battery pack, according to an embodiment of the present invention. The enclosure 102 of the battery pack is shown in first view 100. The battery pack comprises the enclosure 102 for housing the stack 110 of pouch cells 104, characterized in that, a foam pad 108 positioned between the enclosure 102 and extremely positioned pouch cells 104 in the stack 110. Thus, two foam pads 108, one each between two extreme positions within the enclosure 102.

[0009] A first exploded view 112 of the stack 110 of pouch cells 104 is shown. The stack 110 of the pouch cells 104 comprises compression pads 106, placed in between the pouch cells 104.

[0010] According to an embodiment of the present invention, a first surface 304 of the foam pad 108 comprises a layer of acrylic adhesive and a second surface 306 of the foam pad 108 comprises a layer of Ultra High Molecular Weight (UHMW) polyethylene. The first surface 304 and the second surface 306 are opposite to each other. The foam pad 108 itself is made of Polyurethane. The foam pad 108 is described in detail in Fig. 3. The foam pad 108 is positioned in such a manner that the acrylic layer is in contact with surface of the pouch cell 104 and the UHMW layer is in contact with the internal surface of the enclosure 102.

[0011] According to an embodiment of the present invention, the battery pack is disclosed. The battery pack comprises an enclosure 102 for housing the stack 110 of the pouch cells 104, characterized in that, the enclosure 102 is semi-anodized with superimposition of AC on DC waveform with progressive voltages. The anodization is performed in organic and Inorganic acid mixture, specifically Oxalic acid (C2H2O4) + Glycolic acid (C2H4O3) + Sulphuric acid(H2SO4), to achieve layer thickness of 16-24 µm and higher surface finish.

[0012] Fig. 2 illustrates types of foam pads, according to an embodiment of the present invention. The foam pads 108 are designed with cut-outs for thermal management of the pouch cells 104. In Fig. 2, the cut-outs are at least one of a trapezoid shape, a honeycomb shape, and a polygon shape. The trapezoidal shape is already shown in the first exploded view 112 in Fig. 1. In Fig. 2, a first top view 202 shows the foam pad 108 without any cut-out or plane design. A second top view 204 shows the foam pad 108 with cut-out in honeycomb shape. Further, a second exploded view 206 shows the stack 110 with compression pads 106 and foam pads 108 without any cut-out. A third exploded view 208 shows the stack 110 with honeycomb shape cut-out.

[0013] Fig. 3 illustrates the foam pad, according to an embodiment of the present invention. The foam pad 108 comprises the Polyurethane Foam (PF) 302, characterized in that, the first surface 304 of the foam pad 108 comprises the layer of acrylic adhesive and the second surface 306 of the foam pad 108 comprises the layer of Ultra High Molecular Weight (UHMW) polyethylene. The first surface 304 and the second surface 306 are opposite to each other. The first surface 304 offers higher resistance than the second surface 306. The foam pad 108 is used in the battery pack comprising the stack 110 of pouch cells 104. The foam pad 108 is used as a safety pad to prevent scraping of the enclosure 102 and the pouch cells 104.

[0014] In a first side view 300, the foam pad 108 used between the internal surface of the enclosure 102 and the pouch cells 104 is shown. In a second side view 310, the compression pad 106 is shown which is positioned between the pouch cells 104.

[0015] According to an embodiment of the present invention, the stack 110 of pouch cells 104 is assembled inside the enclosure 102 with a predetermined pressure (for example, maximum 9 psi for the stack 110 of pouch cells 104 of 14 series and one parallel configuration). The maximum frictional forces is less than the minimum peel off forces of enclosure 102 and the pouch cell 104. The intermediate abrasive resistant component, i.e. the foam pad 108 is assembled in between the enclosure 102 of the battery pack and pouch cells 104 to avoid material peel off from both pouch cell 104 and the anodized layer of the enclosure 102. The foam pads 108 complies with the heat dissipation requirements.

[0016] According to the present invention, a method for anodizing the enclosure 102 of the battery pack is disclosed. In a first step 402, the enclosure 102 of a specific material (such as AlSi12Cu1(Fe)) is dipped in a bath of chemical solutions. A second step 404 comprises time based passing electric current through the bath solution and the enclosure 102 in low temperature (such as between 5°C to 9°C). The method is characterized by a third step 406 wherein the current supply is performed by superimposing AC on DC waveform with progressing voltage curve. The bath solution is mixture of organic and inorganic acids, specifically Oxalic acid (C2H2O4) + Glycolic acid (C2H4O3) + Sulphuric acid (H2SO4), to achieve layer thickness of 16-24 µm and higher surface finish.

[0017] According to the present invention, a method to assemble stack 110 of pouch cells 104 inside the enclosure 102 of the battery pack with compressible abrasive resistant foam is provided. The material scraping on both pouch cell 104 and enclosure 102 along the direction of assembly is prevented. The semi-hard anodizing process with minimum and maximum thickness of anodic layer to avoid short circuit is provided.

[0018] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:
1. A battery pack, said battery pack comprises an enclosure (102) for housing a stack (110) of pouch cells (104), characterized in that, a foam pad (108) positioned between said enclosure (102) and extremely positioned pouch cells (104) in said stack (110).

2. The battery pack as claimed in claim 1, wherein a first surface (304) of said foam pad (108) comprises a layer of acrylic adhesive and a second surface (306) of said foam pad (108) comprises a layer of Ultra High Molecular Weight (UHMW) polyethylene, wherein said first surface (304) and said second surface (306) are opposite to each other.

3. The battery pack as claimed in claim 2, wherein said foam pad (108) is positioned in such a manner that said acrylic layer is in contact with a surface of said pouch cell (104) and said UHMW layer is in contact with an internal surface of said enclosure (102).

4. The battery pack as claimed in claim 1, wherein said foam pad (108) is designed with cut-outs for thermal management of said pouch cells (104), wherein said cut-outs are at least one of a honeycomb shape, a trapezoid shape, and a polygon shape.

5. The battery pack as claimed in claim 1, wherein said enclosure (102) is anodized by superimposition of AC on DC waveform with progressing voltage curve at low temperatures.

6. The battery pack as claimed in claim 5, wherein said enclosure (102) is treated with organic and inorganic acid mixture, specifically Oxalic acid (C2H2O4) + Glycolic acid (C2H4O3) + Sulphuric acid(H2SO4), to achieve layer thickness of 16-24 µm and higher surface finish.

7. A foam pad (108), said foam pad (108) comprises:
a Polyurethane Foam (PF) (302), characterized in that,
a first surface (304) of said foam pad (108) comprises a layer of acrylic adhesive and a second surface (306) of said foam pad (108) comprises a layer of Ultra High Molecular Weight polyethylene, wherein said first surface (304) and said second surface (306) are opposite to each other.

8. The foam pad (108) as claimed in claim 7, wherein said first surface (304) offers higher resistance than said second surface (306).

9. The foam pad (108) as claimed in claim 7 is used in a battery pack comprising a stack (110) of pouch cells (104).

10. The foam pad (108) as claimed in claim 1 is used as a safety pad to prevent scraping of the enclosure (102) and said pouch cells (104).