DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A METHOD OF MANUFACTURING CELLS IN A LEAKPROOF BATTERY PACK WITH LOW COST COOLING SYSTEM”

APPLICANT:

PADMINI VNA MECHATRONICS LTD.
A company incorporated under the Indian Companies Act, 1956
having address at
Plot No. 100-101, Sector 35, Phase VII, Udyog Vihar, Gurgaon-122001, Haryana, India

PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention generally relates to the field of manufacturing cells. More particularly, the present invention relates to a method of manufacturing cells in a leak-proof battery pack with low cost cooling system for implementing a cooling solution with faster heat transfer at a low cost by sealing contact areas of polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells.

BACKGROUND OF THE INVENTION
Although, advancements have been made in electric vehicle batteries, which allows them to deliver more power and require less frequent charges, however one of the biggest challenges is the ability to design an effective cooling system to ensure safety of the battery. The battery cooling system can generally be categorized into external battery cooling system and internal battery cooling system. The battery cooling system can be categorized into three main categories, which includes liquid or gas cooling with plate type or by using of mini-channel, air cooling and cooling through phase change material (PCM).
Air cooling is widely used in many industries as it is easily available for cooling purposes. However, due to lower heat capacity and low thermal conductivity, air cooling is not an effective coolant. A liquid cooling system provides a high convective heat removal rate due to higher density and higher heat capacity as compared to air cooling system. Therefore, a liquid cooling system is more compact than an air cooling system that up to 40% power can be saved while using liquid cooling system in comparison with air cooling system where fans are required for air cooling, which consumes more power. Also, the liquid cooling can reduce the noise level. However, due to the complexity of the liquid cooling system and its leakage potential, it can be categorized further into direct and indirect liquid cooling system. A cooling through phase change material absorbs heat significantly due to high latent heat during battery discharge. The PCMs have been used for thermal management as it has a melting point in the optimum performing range of lithium cells. The cell temperature needs to remain constant for a long time. However, multiphase modeling needs to be considered while using phase change materials for the cooling of batteries.
Generally, the cells in electric vehicles have to be kept at an optimum temperature. It becomes highly dangerous when the cells in electric vehicles reach higher temperatures, which normally occurs in tropical countries having hotter climates and various other tropical countries. Various methods are used to cool battery packs, such as flowing liquid coolants through pipes and tubes in the vicinity of the cells. Air cooling systems use either a fan or the wind movement by vehicle speed for cooling the batteries. It is to be noted that the method of cooling tubes is highly expensive and space consuming, while air cooling system in hot climates fails to provide enough cooling. Additionally, air cooling systems require a lot of maintenance due to deposition of dust on cells, which in turn can cause problems.
US20090257190A1 discloses about a cooling structure for an electricity storage device includes: a secondary battery generating heat, a dc-dc converter generating heat in a quantity different from that of secondary battery, an exhaust path for passing air after cooling secondary battery generating heat in a relatively small quantity, and led to the outside of a vehicle; an exhaust path for passing air after cooling dc-dc converter generating heat in a relatively large quantity, and joining exhaust path, and a circulation path connected to exhaust path upstream of an air flow beyond a position at which exhaust path joins, and led to the inside of a vehicle compartment. With this configuration, there is provided a cooling structure for an electricity storage device in which the suppression of both increase in temperature and decrease in inner pressure inside the vehicle compartment can be effectively achieved at the same time. The main drawback of this invention is the use of air cooling system as it provides low heat transfer coefficient, uneven temperature distribution and low efficiency.
US6651352B2 discloses about a cooling system of high-voltage battery for vehicle comprises a battery case which is installed in an under floor, an inlet duct which inhales cooling air by being installed in front of the battery case, and an outlet duct which is installed in rear end of the battery case in order to discharge cooling air to outside. The cooling air passed through the outlet duct is exhausted into an indoor trunk of the vehicle. The under floor is formed through lower part of a front seat and lower part of a rear seat of the vehicle. The main drawback of this invention is the use of air cooling system as air cooling system requires a lot of maintenance due to deposition of dust on cells, which in turn can cause problems and such system fails to provide enough cooling in hot climates.
Therefore, due to aforementioned drawbacks, there is a need to develop a method of manufacturing cells in a leak-proof battery pack for implementing a cooling solution with faster heat transfer at a low cost.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a method of manufacturing cells in a leak-proof battery pack with low cost cooling system which provides an efficient cooling system.
Another object of the present invention is to provide a method of manufacturing cells in a leak-proof battery pack with low cost cooling system for implementing a cooling solution with faster heat transfer at a low cost.
Yet another object of the present invention is to provide a method of manufacturing cells in a leak-proof battery pack with low cost cooling system by sealing contact areas of polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells.
Yet another object of the present invention is to provide a method of manufacturing cells in a leak-proof battery pack with low cost cooling system by providing waterproof and/or liquid proof outer periphery of the cells.
Still another object of the present invention is to provide a method of manufacturing cells in a leak-proof battery pack with low cost cooling system to provide efficient heat addition or heat removal depending upon the type of climate where battery is used.

SUMMARY OF THE INVENTION
The present invention relates to a method of manufacturing cells in a leak-proof battery pack for implementing a cooling solution with faster heat transfer at a low cost by sealing contact areas of polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells.
In an embodiment, the present invention provides a method of manufacturing cells in a leak-proof battery pack comprising steps of stacking at least two cells one on top of another, sealing the contact of negative end of one cell to positive end of another cell through an elastomeric seal between a polarities of cells, sealing both radial and axial face of the polarities of cells through said elastomeric seal, sealing is done through one way on the axial face of the polarities of cells or in another way on radial face of the polarities of cells and/or combination of axial face and radial face of the polarities of cells, sealing through axial face includes sealing between the top end of one cell and bottom end of another cell above it, sealing through radial face includes sealing the outer diameter and/or side wall of said polarities of cells, inserting the polarities of cells between a compression plate inner top and a compression plate inner bottom, allowing a plurality of contact plates to go through positive and negative terminals of said polarities of cells wherein, said elastomeric seal makes a contact with top and/or bottom of said polarities of cells along with making a contact with a compression plate thereby forming a seal to protect a polarities of contact areas from a space available around the polarities of cells, cascading the polarities of cells in series wherein a left hand cascading of the polarities of cells provides positive terminals facing downwards and a right hand cascading of the polarities of cells provides positive terminals facing upwards, providing combination of different layouts with cells wherein the height of stack of polarities of cells varies from one cell to many cells, stack of polarities of cells is arranged in parallel with each other to form grid of cells, forming a polarities of individual seals for each stack or a combined seal to seal said polarities of cells adjacent to one another at the same time, thereby reducing a number of components to be assembled and reducing cost and stacking the polarities of cells to show polarity of top of stack of the polarities of cells.
In another embodiment, the present invention provides stacking of said polarities of cells by placing stacks of said polarities of cells parallel to each other to form a grid or/and placing stacks of said polarities of cells in series connection to achieve targeted battery voltage and current capacity, sealing the polarities of cells inter-cell through a polarities of middle elastomer seals, sealing the top and bottom of polarities of cells through said elastomer seal to protect the polarities of cells against an inner compression plate and a bottom compression plate, deriving positive and negative contacts of a polarities of cells through a hole in said inner compression plate and placing above this an outer compression plate, which includes a rigid outer compression plate top and an outer compression plate bottom, inserting a polarities of side walls and pressing together by said outer compression plate, sealing through welding, gluing, elastomer seals and alike joint of said polarities of side walls, clamping together said outer compression plate top and said outer compression plate bottom through snap fitting and/or bolting and welding, pressing together to ensure there is sufficient force to seal said elastomer seal against the polarities of cells and ensuring the positive and negative contact plates make sufficient contact with stack of said polarities of cells, comparing calculation area per volume a around the polarities of cells with area of outside world, introducing a cooling fluid into volume a to flow into the volume a through an inflow orifice in sidewall and/or compression plate, cooling fluid flowing out of volume a through an outflow orifice in sidewall and/or compression plate, protecting terminals of the polarities of cells from said cooling fluid wherein the cooling fluid flows through the polarities of cells, contacting the polarities of cells directly and removing heat when required in higher temperatures and adding heat when required in lower temperatures, ensuring the outer periphery of said polarities of cells is water and/or liquid proof before assembling the polarities of cells in said battery pack.
The present invention relates to a method of manufacturing cells in a leak-proof battery pack with low cost cooling system for implementing a cooling solution with faster heat transfer at a low cost by sealing contact areas of polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings, detailed description of the invention, and claims appended herewith.

BRIEF DESCRIPTION OF THE DRAWING
An understanding of the method of manufacturing cells in a leak-proof battery pack with low cost cooling system of the present invention may be obtained by reference to the following drawing:
Figure 1 shows two cells stacked one on top of another according to an embodiment of the present invention.
Figure 2 shows the cells stacked in a manner where the cells are cascaded in series according to an embodiment of the present invention.
Figure 3 shows a grid of cells according to an embodiment of the present invention.
Figure 4 shows the complete assembly with only one stack of two cells shown for illustration purpose according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The present invention provides a method of manufacturing cells in a leak-proof battery pack with low cost cooling system for implementing a cooling solution with faster heat transfer at a low cost by sealing contact areas of polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells.
In an embodiment, the present invention provides a method of manufacturing cells in a leak-proof battery pack with low cost cooling system comprising steps of stacking at least two cells one on top of another, sealing the contact of negative end of one cell to positive end of another cell through an elastomeric seal between a polarities of cells, sealing both radial and axial face of the polarities of cells through said elastomeric seal, sealing is done through one way on the axial face of the polarities of cells or in another way on radial face of the polarities of cells and/or combination of axial face and radial face of the polarities of cells, sealing through axial face includes sealing between the top end of one cell and bottom end of another cell above it, sealing through radial face includes sealing the outer diameter and/or side wall of said polarities of cells, inserting the polarities of cells between a compression plate inner top and a compression plate inner bottom, allowing a plurality of contact plates to go through positive and negative terminals of said polarities of cells wherein said elastomeric seal makes a contact with top and/or bottom of said polarities of cells along with making a contact with a compression plate thereby forming a seal to protect a polarities of contact areas from a space available around the polarities of cells, cascading the polarities of cells in series wherein a left hand cascading of the polarities of cells provides positive terminals facing downwards and a right hand cascading of the polarities of cells provides positive terminals facing upwards, providing combination of different layouts with cells wherein the height of stack of polarities of cells varies from one cell to many cells, stack of polarities of cells is arranged in parallel with each other to form grid of cells, forming a polarities of individual seals for each stack or a combined seal to seal said polarities of cells adjacent to one another at the same time, thereby reducing a number of components to be assembled and reducing cost and stacking the polarities of cells to show polarity of top of stack of the polarities of cells.
In another embodiment, the present invention provides stacking of said polarities of cells by placing stacks of said polarities of cells parallel to each other to form a grid or/and placing stacks of said polarities of cells in series connection to achieve targeted battery voltage and current capacity, sealing the polarities of cells inter-cell through a polarities of middle elastomer seals, sealing the top and bottom of polarities of cells through said elastomer seal to protect the polarities of cells against an inner compression plate and a bottom compression plate, deriving positive and negative contacts of a polarities of cells through a hole in said inner compression plate and placing above this an outer compression plate, which includes a rigid outer compression plate top and an outer compression plate bottom, inserting a polarities of side walls and pressing together by said outer compression plate, sealing through welding, gluing, elastomer seals and alike joint of said polarities of side walls, clamping together said outer compression plate top and said outer compression plate bottom through snap fitting and/or bolting and welding, pressing together to ensure there is sufficient force to seal said elastomer seal against the polarities of cells and ensuring the positive and negative contact plates make sufficient contact with stack of said polarities of cells, comparing calculation area per volume around the polarities of cells with area of outside world, introducing a cooling fluid into volume a to flow into the volume a through an inflow orifice in sidewall and/or compression plate, cooling fluid flowing out of volume a through an outflow orifice in sidewall and/or compression plate, protecting terminals of the polarities of cells from said cooling fluid wherein the cooling fluid flows through the polarities of cells, contacting the polarities of cells directly and removing heat when required in higher temperatures and adding heat when required in lower temperatures, ensuring the outer periphery of said polarities of cells is water and/or liquid proof before assembling the polarities of cells in said battery pack.
Figure 1, shows the two cells stacked one on top of another is depicted. At least two cells are stacked with one on top of another and stack height vary from two to several cells & several stacks can be parallel and perpendicular as per the requirement of current/voltage, the contact of one negative end of one cell is sealed to the positive end of another cell through an elastomeric seal (2) between polarities of cells. Both radial and axial face of the polarities of cells are sealed through elastomeric seal (2), sealing is done in one way on the axial face of the polarities of cells or in another way on radial face of the polarities of cells and/or combination of axial face and radial face of the polarities of cells, sealing through axial face includes sealing between the top end of one cell and bottom end of another cell above it, sealing through radial face includes sealing the outer diameter and/or side wall of said polarities of cells. The polarities of cells are inserted between a compression plate inner top (5) and a compression plate inner bottom (8), which allows a pluralities of contact plates (1) to go through positive and negative terminals of defined polarities of cells wherein said elastomeric seal (2) makes a contact with top and/or bottom of said polarities of cells along with making a contact with contact plate (1) thereby forming a seal to protect a polarities of contact areas from a space available around the polarities of cells.
Figure 2, shows the cells stacked in a manner where the cells are cascaded in series is depicted. It shows cascading of the polarities of cells in series wherein a left hand cascading of the polarities of cells provides negative terminal (3) and positive terminal (4) facing downwards and a right hand cascading of the polarities of cells provides negative terminal (3) and positive terminal (4) facing upwards. It also provides that a compression plate inner top (5) stacked through negative terminal (3) and positive terminal (4) facing downwards and a compression plate inner bottom (8) stacked through negative terminal (3) and positive terminal (4) facing upwards. The combination of different layouts with cells are provided wherein the height of stack of polarities of cells varies from one cell to many cells, stack of polarities of cells is arranged in parallel with each other to form grid of cells, a pluralities of individual seals (6) are formed for each stack or a combined seal (7) to seal said polarities of cells adjacent to one another at the same time, thereby reducing a number of components to be assembled and reducing cost and stacking the polarities of cells to show polarity of top of stack of the polarities of cells. It also provides adding more columns (9) as needed.
Figure 3, shows a grid of cells (10) to depict the polarity of top of the stacks of polarities of cells. Figure 4, shows the complete assembly with only one stack of two cells shown for illustration purpose. The stacks of said polarities of cells are placed in series connection to achieve targeted battery voltage and current capacity, the polarities of cells inter-cell are sealed through a polarities of middle elastomer seals (2), the top and bottom of polarities of cells are sealed through said elastomer seal (2) to protect the polarities of cells against said compression plate inner top (5) and a compression plate inner bottom (8). The positive contact plate (4) and negative contact plate (3) are derived from a polarities of cells through a hole in said compression plate inner top (5) and placing above this an outer compression plates which includes a compression plate outer top (13), which is rigid and a compression plate outer bottom (14). A plurality of side walls is inserted and pressed together by said outer compression plates (13) and (14), then sealed through a technique including but not limited to welding, gluing, elastomer seals (2) or alike joint between said polarities of side walls, clamping together said compression plate outer top (13) and said compression plate outer bottom (14) through snap fitting and/or bolting and welding. The compression plates are pressed together to ensure that there is sufficient force to seal said elastomer seal (2) against the polarities of cells and ensuring the positive contact plate (4) and the negative contact plate (3) make sufficient contact with stack of said polarities of cells. A side wall (12) encloses the complete assembly with only one of the two cells stacked and an air space ‘A’ (11) is provided inside the closed assembly of the stacked cells.
EXAMPLE 1
WORKING METHOD OF MANUFACTURING CELLS IN A LEAK-PROOF BATTERY PACK
The present invention provides a method of manufacturing cells for a leak-proof battery pack. The stack of cells are from 1 to several cells high, and there are possibly several stacks placed parallel to each other is a grid, for example a grid of A x B with a stack height of C cells. In this case the number of cells in the pack would be A x B x C (A multiplied by B multiplied by C). Further, there is provision for some of the stacks to be in series connection, and some of the stacks to be in parallel connection, thereby achieving the targeted battery voltage and current capacity.
Furthermore, the cells are sealed by the middle elastomer seals. At the top and bottom of the cell, the elastomer seal (2) seals the cell against the compression plate inner top (5) and compression plate inner bottom (8). The positive and negative contacts come through the hole in the inner compression plates. Above this, there is a rigid outer compression plate top (13), and outer compression plate bottom (14). To complete the assembly, there are side walls (12) that are sandwiched and pressed together by the outer compression plates. The joint of the side walls (12) to the compression plates is sealed by welding/gluing/elastomer seal etc. The outer compression plate top and outer compression plate bottom (13, 14) are clamped together either by snap fitting, or by bolting or by welding and they are pressed together to ensure there is enough force to seal the elastomer seals (2) against the cells and to ensure that the positive and negative contact plates make sufficient contact with the stack of cells. This arrangement now give the area/volume A around the cells as a sealed volume against the outside world. So now, a cooling fluid is introduced into the volume A, to flow in and out through the side wall (12) and/or the compression plates. The coolant then flow into the volume A through an inflow orifice (either in the sidewall, or in the compression plate) and flow out through an outflow orifice (either in the sidewall and or in the compression plate). Since the elastomeric seals are now protecting the terminals of the cells from the fluid, the fluid flows by the cells, directly contacting the cells and efficiently removing heat if required, or adding heat where required in cooler climates. Additionally, before assembly of the cells into the battery pack the outer periphery of the cells are checked to ensure that the outer periphery is water/liquid proof.
Therefore, the present invention provides a method of manufacturing cells in a leak-proof battery pack for implementing a cooling solution with faster heat transfer at a low cost by sealing contact areas of a polarities of cells assembled together and cooling the cells with sealed contact areas through flowing a liquid directly over the cells. The method of manufacturing cells provides a leak-proof battery pack, comprising steps of stacking at least two cells one on top of another, sealing the contacts of negative end of one cell to positive end of another cell through an elastomeric seal between a polarities of cells, sealing both radial and axial face of the polarities of cells through said elastomeric seal, sealing is done through one way on the axial face of the polarities of cells or in another way on radial face of the polarities of cells and/or combination of axial face and radial face of the polarities of cells, sealing through axial face includes sealing between the top end of one cell and bottom end of another cell above it and sealing through radial face includes sealing the outer diameter and/or side wall of said polarities of cells.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.
,CLAIMS:CLAIMS

We claim:
1. A method of manufacturing cells in a leak proof battery pack, comprising steps of:
(a) stacking at least two cells, one on top of another;
(b) sealing a contact of two polarities of the cells that is a negative terminal (3) of one cell to a positive terminal (4) of another cell through an elastomeric seal (2) upon said stacking of the cells;
(c) performing sealing on an axial face, a radial face, or a combination of the axial face and radial face of the polarities of the cells, wherein the sealing through the axial face includes sealing between a top end of one cell and a bottom end of another cell and the sealing through the radial face includes sealing an outer diameter and/or side wall of the polarities of the cells, upon sealing the contact of two polarities of the cells;
(d) sandwiching the cells between a compression plate inner top (5) and a compression plate inner bottom (8) upon sealing in step (c);
(e) allowing contact plate (1) for the polarities of cells to go through the compression plate inner top (5) and the compression plate inner bottom (8), wherein the elastomeric seal (2) make contact with the top or bottom end of the cell along with the compression plate inner top (5) and the compression plate inner bottom (8), thereby forming a seal to protect a contact area from a space around the cells;
(f) sealing the cells via the elastomer seal (2) against the compression plate inner top (5) and compression plate inner bottom (8), wherein the positive terminal (4) and negative terminal (3) come through a hole in an inner compression plate to form an assembly;
(g) cascading the polarities of the cells in series which include a left-hand cascading for providing positive terminal (4) facing downwards and a right-hand cascading for providing positive terminal (4) facing upwards, upon sealing the cells via the elastomer seal (2) in step (f);
(h) varying a height of a stack of polarities of cells and arranging the stack of polarities of cells in parallel to form a grid of cells (10);
(i) forming a plurality of individual seals for each stack or a combined seal to seal the polarities of cells adjacent to one another at the same time, thereby reducing number of components and assembly cost; and
(j) stacking the polarities of cells to indicate the polarity of top of the stack of the polarities of cells.
2. The method of manufacturing cells in a leak proof battery pack as claimed in claim 1 , wherein said stack of polarities of cells is arranged in parallel or series manner for achieving a targeted battery voltage and current capacity.
3. The method of manufacturing cells in a leak proof battery pack as claimed in claim 1, wherein said assembly include a plurality of side walls (12) that are sandwiched and pressed together by at least two outer compression plates (13, 14).
4. The method of manufacturing cells in a leak proof battery pack as claimed in claim 3, wherein said side walls (12) are joint with the compression plates via welding or gluing or elastomer seal (2).
5. The method of manufacturing cells in a leak proof battery pack as claimed in claim 3, wherein said two outer compression plates (13, 14) are clamped together either by snap fitting, or by bolting or by welding and pressed together to ensure there is force to cover the elastomer seal (2) against the cells and to ensure that the contact plate (1) make contact with the stack of cells.