Multilayer protection elements for batteries

Abstract

The present invention relates to a multi-layer protective element (20) for a battery (1) having at least two adjacent battery cells (10), the protective element (20) being positionable between the battery cells (10), the protective element (20) having a compressible core layer (21). According to the present invention, the core layer (21) is primarily composed of animal hair, and the thickness of the core layer is between 60% and 98% of the total thickness of the protective element. The present invention also relates to a battery (1) and uses of the protective element (20) for the battery (1).

Description

[Technical Field]

[0001] [explanation] The present invention relates to a multilayer protective element for a battery having at least two battery cells. The present invention also relates to a battery having a multilayer protective element and to the use of the protective element as an intermediate layer between two battery cells. [Background technology]

[0002] US 10,840,494 B2 discloses a battery comprising multiple prismatic battery cells in the shape of a flattened rectangular parallelepiped, arranged adjacent to each other on their respective large sides. Starting from an uncharged state, individual battery cells expand during charging, increasing their thickness—that is, the distance between their two large sides. This expansion of adjacently arranged battery cells can lead to overall battery expansion, potentially causing problems. For example, if the battery cells are housed within a battery housing, the expansion of each individual battery cell can cause plastic deformation and damage to the battery housing. According to US 10,840,494 B2, to compensate for the expansion of the battery cells, a protective element arranged between two adjacent battery cells has a compressible core layer. As the battery cells expand, this core layer compresses, so the total thickness of the battery pack, consisting of the individual battery cells and the protective element arranged between them, remains substantially unchanged during battery charging. A plastic material with a relatively low Shore hardness is proposed as the core layer material.

[0003] In addition to compensating for battery cell expansion, protective elements must also perform thermal and electrical shielding functions. Lithium-ion batteries, in particular, are highly unstable due to their chemical composition. For example, a local short circuit between the internal electrodes of a battery cell can generate a strong short-circuit current, rapidly heating the affected battery cell. This thermal runaway in a battery cell can easily and quickly spread to adjacent battery cells. This can cause a chain reaction, resulting in the explosive release of energy stored in the battery. This explosive energy release can be accompanied by the generation of toxic gases, flames, and sparks. Therefore, protective elements must have low thermal conductivity, high insulating strength, and high heat resistance (fire resistance).

[0004] Furthermore, batteries and their components need to be easy to recycle: when discarding a used battery, it is possible to separate the multilayer protective element from the battery cell and recycle it, but if the individual layers of the protective element are made of different plastic materials, the protective element cannot be recycled in an environmentally friendly way.

[0005] It is therefore an object of the present invention to provide a protective element for a battery that is compressible, insulating, has high dielectric strength and is as environmentally friendly as possible.

[0006] The object of the invention is achieved by the combination of features set forth in claim 1. Exemplary embodiments of the invention are set forth in the dependent claims to claim 1.

[0007] According to the present invention, the compressible core layer primarily comprises animal hair (wool). In a preferred embodiment, sheep's wool is used. The use of wool in the compressible core layer provides a protective element (also known as a battery compression pad) that is easily compressed and has excellent compressibility. Meanwhile, its low thermal conductivity of less than 0.05 W / mK provides very good thermal insulation. Furthermore, the use of wool is environmentally friendly. Wool is a natural, renewable product and can be easily recycled. For example, used sheep's wool can be used as fertilizer.

[0008] Types of animal hair other than sheep's wool include angora, mohair, cashmere, and alpaca.

[0009] The proportion of wool in the core layer can be up to 100%. For example, the core layer may be composed of up to 80%, 90%, or 100% wool. Preferably, the proportion of wool in the core layer is between 60% and 100%, and particularly preferably between 80% and 100%. The core layer may be a nonwoven material in which multiple layers are stacked or folded. The core layer may also be made of felt. Felt utilizes the intertwining properties of wool yarns. Pure new wool, in particular, is flame-retardant and has excellent thermal insulation properties. The wool core layer may also be composed of different sub-layers. For example, the core layer may include a first nonwoven layer, a second nonwoven layer, and a felt layer arranged between the two nonwoven layers.

[0010] The basis weight of the core layer is 80g / m 2 More than 1800g / m 2 The preferred basis weight is 100 g / m 2 More than 1000g / m 2 or less, or 200 g / m 2 More than 800g / m 2 The following is the result.

[0011] According to the present invention, the total thickness of the protective element is determined to a large extent by the thickness of the core layer, which is between 60% and 98% of the total thickness of the protective element.

[0012] The overall width of the protective element is between 0.5 mm and 12 mm. By way of example, the overall thickness is between 1.0 mm and 10.5 mm. The tolerance is preferably within the range of + / - 0.01 mm to + / - 1 mm. According to the invention, the compressible core layer has a thickness (unloaded) of between 60% and 98% of the overall thickness of the protective element, in a preferred embodiment between 1.5 mm and 10 mm. The tolerance is preferably within the range of + / - 0.01 mm to + / - 1 mm.

[0013] The multilayer protective element may have at least a first barrier layer, which preferably comprises mica. Mica is heat-resistant and fire-resistant. Mica does not refer to a specific mineral, but rather to a group of minerals known as the mica group, which share a common chemical composition and crystal lattice structure.

[0014] The protective element may have a second barrier layer, and the core layer may be disposed between the two barrier layers. One of the two thermal barrier layers may constitute a first outer layer of the protective element.

[0015] The second outer layer of the protective element can be formed by an adhesive layer. This adhesive layer may consist of a protective release liner that must be removed before adhering to the battery cell. If the first outer layer is not designed to be adhesive, one side of each individual battery cell can be laminated with the second outer layer of the protective element during battery manufacturing. Because the first outer layer is not designed to be adhesive, the battery cells, each with their respective protective elements, can be placed side by side as a package and then precisely aligned with each other.

[0016] A further object of the present invention, namely, the provision of a reliable, safe, and environmentally friendly battery, is achieved by claim 9. Therefore, a battery is proposed, which has at least two battery cells, between which a multilayer protective element according to any one of claims 1 to 8 is arranged. The protective element may have a design as defined in the present disclosure. At least one battery cell may have a prismatic basic shape, preferably a rectangular parallelepiped basic shape. The battery cells may also be designed as pouches. Preferably, all battery cells of the battery have a prismatic basic shape. By way of example, all battery cells are designed as pouches.

[0017] Furthermore, the invention proposes using a multilayer protection element according to any one of claims 1 to 8 as an intermediate layer between two battery cells of a battery.

[0018] The invention will now be explained in more detail with reference to exemplary embodiments shown in the drawings. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows a schematic diagram of a battery having a plurality of battery cells and a plurality of protection elements provided between the battery cells. [Figure 2] FIG. 2 shows an example of the layer structure of the protective element. DETAILED DESCRIPTION OF THE INVENTION

[0020] Figure 1 shows schematically a battery, generally designated 1. The battery may, for example, be a battery used to power an electric vehicle.

[0021] The battery 1 includes a plurality of battery cells 10. Although five battery cells 10 are shown in FIG. 1, the battery 1 may include fewer or more battery cells (e.g., 10 battery cells). Each battery cell 10 has a basic rectangular parallelepiped shape. The height H of each battery cell 10 is 10 The width of the representation of FIG. 1 extending into the drawing plane can be, for example, between 50 mm and 300 mm. The thickness of the battery cell 10 is D 10 and can be, for example, 10 mm or more and 50 mm or less.

[0022] A protection element 20 is disposed between two adjacent battery cells 10. The thickness D of each protection element 20 is 20 In a preferred embodiment, the height H of the protection element 20 is 3 mm or more and 8 mm or less. The spatial expansion (height and width) of the protection element 20 can accommodate the spatial expansion of the battery cell 10. In the embodiment of FIG. 1, the height H of the protection element 20 is 3 mm or more and 8 mm or less. 20 is the height H of the battery cell 10 10 Slightly smaller than

[0023] Figure 2 shows the layer structure of protective element 20. For clarity, each layer of multi-layer protective element 20 is shown spaced apart. Like Figure 1, Figure 2 is not a scale drawing.

[0024] Protective element 20 includes a compressible core layer 21 made of wool. Core layer 21 is disposed between first and second barrier layers 22 and 23, each of which includes mica. First barrier layer 22 is the first outer layer of protective element 20.

[0025] Second barrier layer 23 is positioned between core layer 21 and adhesive layer 24, which includes release liner 25. Adhesive layer 24 (with release liner 25) forms the second outer layer of protective element 20. Further adhesive layers 26, 27 are provided between barrier layers 22, 23 and core layer 21.

[0026] To adhere the protective element 20 to the battery cell 10, the release liner 25 is peeled away to expose the adhesive of the adhesive layer 24, which can then be placed onto the appropriate battery cell 10. The battery cell 10 and the attached protective element 10 form a unit that can be placed adjacent to one another in a package / stack along with other units thus produced. The non-adhesive exterior of each unit allows the units to be aligned with one another even when already in a package or stack. [Explanation of symbols]

[0027] 1 battery 10 battery cells 20 Protection Elements 21 Core layer 22 First Barrier Layer 23 Second Barrier Layer 24 Adhesive layer 25 Release Liner 26 Adhesive layer 27 Adhesive layer

Claims

1. A multilayer protective element (20) for a battery (1) having at least two adjacently arranged battery cells (10), comprising: The protection element (20) can be arranged between the battery cells (10), The protective element (20) has a compressible core layer (21), The core layer (21) is mainly composed of animal hair, The thickness of the core layer (21) is 60% or more and 98% or less of the total thickness of the protective element (20). Multilayer protection element for batteries.

2. The proportion of wool in the core layer (21) is in the range of 60% or more and 100% or less. A protective element (20) according to claim 1.

3. The core layer (21) comprises wool. A protective element (20) according to claim 1 or claim 2.

4. characterised in that the core layer (21) is a nonwoven material or wool felt, A protective element (20) according to any one of claims 1 to 3.

5. The basis weight of the core layer (21) is 200 g / m ２ More than 1000g / m ２ characterized in that: A protective element (20) according to any one of claims 1 to 4.

6. characterized in that it is provided with a first barrier layer (22), preferably comprising mica; A protective element (20) according to any one of claims 1 to 5.

7. a second barrier layer (23) is provided; The core layer (21) is disposed between a first barrier layer (22) and a second barrier layer (23). A protective element (20) according to claim 6.

8. one of the two thermal barrier layers (22, 23) being a first outer layer of the protective element (20), A protective element (20) according to claim 7.

9. The second outer layer is formed by an adhesive layer (24) having a release liner (25). A protective element (20) according to any one of claims 1 to 8.

10. The battery comprises at least two battery cells (10) between which a multilayer protection element (20) according to any one of claims 1 to 9 is arranged. Battery (1).

11. A multilayer protection element (20) according to any one of claims 1 to 9 is interposed between two battery cells (10) of a battery (1). use.

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