A battery cell with an expansion-absorbing cell pouch

Abstract

The present invention relates to a battery cell (1) having an expansion-absorbing battery cell pouch (4), which can compensate for the expansion and size increases that may occur after aging of the battery cell of battery modules realized by using battery cells in module production that are part of electric vehicle batteries.

Description

[0001] DESCRIPTION

[0002] A BATTERY CELL WITH AN EXPANSION-ABSORBING CELL POUCH

[0003] Technical Field

[0004] The present invention relates to a battery cell having an expansion-absorbing battery cell pouch, which can compensate for the expansion and size increases that may occur after aging of the battery cell of battery modules realized by using battery cells in module production that are part of electric vehicle batteries.

[0005] Background of the Invention

[0006] Today, lithium battery cells are widely used in electric vehicles due to their high charge and discharge capacities and high energy density. During the use of lithium battery cells, their internal pressure increases due to the electro-chemical properties of the cell, and accordingly, conditions such as expansion of the cells and increase in cell thickness occur. This situation is relevant for all battery cells and is especially critical for battery packs. If the assembly is carried out without taking into account the situation that the battery cell may expand in the future during module assembly, the internal pressure of the cell increases due to cell aging, which causes the cell to expand and its thickness to increase. If the cell is unable to expand, this pressure difference can increase in total and cause the battery cell to undergo thermal runaway due to high pressure. In addition, under high pressure, the cell electrodes may crack, resulting in a rapid loss of capacity and the battery pack may become unusable. In the event that the pressure inside the cell cannot be balanced on the outside of the cell, permanent damage and even irreversible accidents such as combustion, explosion and melting are possible.

[0007] In the current technique, in order to compensate for the pressure difference that may occur in the battery packs, firstly, the required expansion analyses are carried out and appropriate foam or elastomer pads are used between the battery cells after determining the maximum pressure value that the cell can withstand. These used pads or foam materials are added between each cell during the cell riveting stage before module assembly. However, this process causes the battery cell assembly to take a long time and requires the use of a separate automation, software and machine park and control point for this process. In order to overcome the mentioned deficiencies, there is a need for a battery cell having a self-expansion-absorbing battery cell pouch.

[0008] The Chinese patent document no. CN110079020, an application included in the state of the art, discloses a flame-retardant polypropylene material design. The invention subject to the said Chinese patent document provides a flame-retardant polypropylene material for a cover of a new energy vehicle battery pack and a preparation method of the flame-retardant polypropylene material. The flameretardant polypropylene material is obtained by melt-mixing polypropylene with a first additive and a second additive; the introduction of the foaming process enables the product density to be greatly reduced, thereby meeting the lightweight requirements on the cover of the new energy vehicle battery pack. The first additive is prepared from carbon fiber powder, wollastonite powder, hollow glass microbeads, hexamethylenetetramine and other raw materials, and the second additive is prepared from a sodium carboxymethyl cellulose aqueous solution, polyvinyl alcohol, aluminium dihydrogen phosphate, sodium polyphosphate, polyhexamethylene guanide hydrochloride, oxidized modified graphite and other raw materials. The introduction of the above components effectively improves the mechanical properties and flame retardant properties of the product, so that the product can satisfy the high standard requirements on the cover of the new energy vehicle battery pack.

[0009] Summary of the Invention An object of the present invention is to realize a battery cell having an expansionabsorbing battery cell pouch, which can compensate for the expansion and size increases that may occur after aging of the battery cell of battery modules realized by using battery cells in module production that are part of electric vehicle batteries.

[0010] Detailed Description of the Invention

[0011] “A Battery Cell with an Expansion-Absorbing Cell Pouch” realized to fulfil the objective of the present invention is shown in the figures attached, in which:

[0012] Figure 1 is a general view of the inventive battery cell.

[0013] Figure 2 is another view of the inventive battery cell.

[0014] The components illustrated in the figures are individually numbered, where the numbers refer to the following:

[0015] 1. Battery cell

[0016] 2. Foam

[0017] 3. Isolator

[0018] 4. Cell pouch

[0019] 5. Stack layer

[0020] 6. Cell stripe

[0021] An inventive battery cell (1) having an expansion-absorbing battery cell pouch, which can compensate for expansion and size increases that may occur after aging of the battery cell in electric vehicle batteries comprises; at least one foam (2) which has pressure absorbing properties; at least one isolator (3) which enables the foam (2) to be coated in order to provide electrical isolation and sealing; at least one self-foamed (2) laminated battery cell pouch (4) which is laminated with foam (2) having the isolator (3) by means of polypropylene on aluminum foil; at least one cell stack layer (5) which is placed between two cell pouches (4); and at least one cell stripe (6) which extends out from the stack layer (5) and is the negative and positive connections of the cell.

[0022] The foam (2) included in the inventive battery cell (1) is an elastomer material used to absorb cell expansion and size increases that may occur after aging. In one embodiment of the invention, the foam (2) is silicone. In one embodiment of the invention, the foam (2) is a self-elastomer pad.

[0023] The isolator (3) included in the inventive battery cell (1) surrounds the foam (2) and is a polypropylene material.

[0024] The cell pouch (4) included in the inventive battery cell (1) consists of aluminum foil laminated with polypropylene. The cell pouch (4) is a pouch produced from aluminum, polypropylene, foam (2), polypropylene isolator (3), respectively. The cell pouch (4), unlike existing battery cells, has a self-elastomeric form as it comprises the foam (2) and the isolator (3) structures.

[0025] The stack layer (5) included in the inventive battery cell (1) is anode and cathode materials riveted to each other.

[0026] Industrial Application of the Invention

[0027] Since the cell walls of the cell pouch (4) included in the inventive battery cell (1) are produced by using self-elastomer foam (2), the operation of supporting with foam under mass production conditions is completely eliminated, production capacity is increased, quality errors are reduced, and possible accidents or irreversible damages that may occur to the battery pack in case of forgetting or overlooking to put foam can be prevented. The presence of a self-foamed (2) cell pouch (4) coated with polypropylene in the battery cell (1) increases the resistance of the battery cell (1) to thermal runaway or thermal dissipation.

[0028] The battery cell (1) having the inventive cell pouch (4) has some advantages compared to battery cells with external foam or pad applications. One of these is ease of assembly. The foam (2) material used between each cell requires significant automation, software and a machine park in order to be placed in sequence and in proper alignment under mass production conditions. With the inventive battery cell (1), the foam insertion or assembly step during the cell riveting operation is completely eliminated, providing convenience for assembly, automation and activation. Another advantage is achieving high quality and repeatability. In the inventive battery cell (1), by means of the foam (2) or selfelastomer pad that will be directly on the cell pouch (4), there is no need for foam / pad products that need to be fed separately next to the line in mass production lines. In addition, repeatability in production conditions is achieved by enabling the foam / pads to remain in the same location at all times during assembly. There is no need to check the foam placement in standard production, thereby enabling one of the possible quality control points to be eliminated. Since the step of placing foam material between the cells during the module riveting process applied when obtaining the battery cell is completely eliminated, a positive effect is created by reducing production time.

[0029] Within these basic concepts; it is possible to develop various embodiments of the inventive “A System (1) for Controlling the Mechanical Behaviour of Batteries”; the invention cannot be limited to examples disclosed herein and it is essentially according to claims.

Claims

CLAIMS1. A battery cell (1) having an expansion-absorbing battery cell pouch, which can compensate for expansion and size increases that may occur after aging of the battery cell in electric vehicle batteries; characterized in that it comprises at least one foam (2) which has pressure absorbing properties; at least one isolator (3) which enables the foam (2) to be coated in order to provide electrical isolation and sealing; at least one self-foamed (2) laminated battery cell pouch (4) which is laminated with foam (2) having the isolator (3) by means of polypropylene on aluminum foil; at least one cell stack layer (5) which is placed between two cell pouches (4); and at least one cell stripe (6) which extends out from the stack layer (5) and is the negative and positive connections of the cell.

2. A battery cell (1) according to Claim 1; characterized by the foam (2) which is an elastomer material used to absorb cell expansion and size increases that may occur after aging.

3. A battery cell (1) according to Claim 1 or 2; characterized by the foam (2) one example of which is silicon or self-elastomer pad.

4. A battery cell (1) according to any one of the preceding claims; characterized by the isolator (3) which surrounds the foam (2) and is a polypropylene material.

5. A battery cell (1) according to any one of the preceding claims; characterized by the cell pouch (4) which consists of aluminum foil laminated with polypropylene.

6. A battery cell (1) according to any one of the preceding claims; characterized by the cell pouch (4) which is a pouch produced from aluminum, polypropylene, foam (2), polypropylene isolator (3), respectively.

7. A battery cell (1) according to any one of the preceding claims; characterized by the cell pouch (4) which has a self-elastomeric form as it comprises the foam (2) and the isolator (3) structures.

8. A battery cell (1) according to any one of the preceding claims; characterized by the stack layer (5) which is anode and cathode materials riveted to each other.

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