Housing system and battery cell comprising such housing system

Abstract

A battery cell (10) and a housing system (14) for a battery cell (10), the housing system comprising a housing having a bottom and a side wall, the bottom and the side wall comprising a conductive layer (22) comprising a metallic material, and the side wall further comprising a barrier layer, the barrier layer surrounding and in surface contact with the conductive layer, the bottom having no barrier layer, the barrier layer comprising a metal material, and the barrier layer comprising a metal material. And wherein a thermal resistance of the barrier layer is higher than a thermal resistance of the conductive layer.

Description

Technical Field

[0001] The invention relates to a battery housing system and a battery unit comprising such a housing system. More specifically, the field of the invention is batteries for hybrid or electric vehicles, wherein energy is stored in accumulators. Background Art

[0002] As electric vehicle technology continues to advance, there is a need to provide improved power sources for such vehicles, particularly battery subassemblies. For example, it is desirable to minimize the complexity of the battery subassembly to reduce costs associated with manufacturing and to better manage heat propagation within such battery subassembly.

[0003] In this document, the terms "battery cell", "battery module", "battery section" and "battery pack" (and their abbreviated variants "battery", "module", "section" and "pack") are used to describe components of different levels of the entire battery assembly or battery device. Conventionally, a battery cell (such as a lithium-ion battery cell) includes a housing (or housing system) and battery cell materials encapsulated within the housing. The battery cell materials include one or more cathodes, one or more anodes, an electrolyte and a separator, which is composed of a porous polymer or other suitable material to avoid direct contact between the electrodes. Many individual battery cells form part of a battery module. Multiple battery modules (together with auxiliary equipment) in turn constitute a battery pack.

[0004] As performance improves, batteries are required to have more diverse shapes and reduced thickness and weight. Battery cell housings and cases need to accommodate the diversification of shapes without increasing weight.

[0005] US2008286635A1 discloses a battery package having a film-like laminate including a substrate, a barrier layer and a heat-sealable resin layer laminated in sequence as a battery packaging material, which is easily processed into various shapes and can achieve reduction in thickness and weight.

[0006] EP3467897A1 relates to a battery packaging material comprising a laminate having at least a barrier layer, a heat-sealable resin layer on one surface side of the barrier layer, and a polyester film on the other surface side of the barrier layer. This battery packaging material is easy to shape.

[0007] However, there remains a need to provide a cell housing system that is compact, lightweight, and does not degrade the performance of the battery cell materials. Summary of the invention

[0008] The present disclosure aims to solve the above-mentioned problems. Therefore, the present invention relates to a housing system according to claim 1 and a battery unit according to claim 12.

[0009] More specifically, the housing system defines a recess for receiving battery cell material. The housing system includes a cover and a housing, the cover and the housing cooperating to define the recess. The housing includes a bottom and a side wall. The side wall and the bottom include a conductive layer containing a metal material, the conductive layer directly defining the recess. The side wall also includes a barrier layer made of a barrier layer material, wherein the barrier layer surrounds the conductive layer and is in surface contact with the conductive layer, and the bottom does not have the barrier layer. The barrier layer includes an intermediate plate, and a plurality of isolation gaps are provided on both sides of the intermediate plate. The thermal resistance of the barrier layer is higher than the thermal resistance of the conductive layer.

[0010] This structure allows simple thermal management of the battery cells. The barrier layer is only on the side walls, and there is no barrier layer at the bottom, so heat transfer can be carried out through the bottom. The housing system can be compact and easy to manufacture. For example, the conductive layers forming the bottom and the side walls can be integrated or connected together by sheet material bending techniques, which are processes used, for example, in food, cosmetics, medicine and many other fields. The sides of the housing are thermally isolated so that heat does not spread (or spreads less) laterally to other battery cells. This housing system is then suitable for forming a battery subassembly with thermal management and thermal safety functions.

[0011] In this application, the "thermal management" function and goal refers to keeping the battery and its individual subcomponents within the desired temperature limits (minimum and maximum values) and keeping the desired variation (ΔT) between one subcomponent and another. The "thermal safety" function refers to limiting the heat propagation between battery subcomponents, especially between battery cells, with the goal of preventing thermal runaway events.

[0012] The barrier layer comprises a plurality of isolation gaps (particularly fluid gaps, especially air gaps), which form an isolation space to prevent heat transfer.

[0013] In one embodiment, the barrier layer comprises a plurality of paper sheets. In one embodiment, the intermediate sheet is a paper sheet, in particular a mica paper. The plurality of paper sheets may be arranged to form an insulating gap. Paper is light in weight and ensures thermal isolation by creating an air gap.

[0014] In one embodiment, the barrier layer material has a strength of less than 1 W·m -1 ·K -1 Thermal conductivity. The barrier layer material has low thermal conductivity to avoid heat transfer.

[0015] In one embodiment, the conductive layer material has a strength greater than 5 W·m -1 ·K -1More specifically, in one embodiment, the conductive layer is made of copper material.

[0016] In an alternative embodiment, the conductive layer comprises a first sublayer and a second sublayer. The thermal conductivity of the first sublayer may be greater than 5 W·m -1 ·K -1 The thermal conductivity of the second sublayer can be greater than 5 W·m -1 ·K -1 In contrast to the barrier layer material, the first sublayer material and / or the second sublayer material has a high thermal conductivity in order to receive and transfer heat from the battery cell material.

[0017] In one embodiment, the first sublayer material is steel or aluminum, and the second sublayer material is graphite. In one embodiment, on the sidewall, the second sublayer is arranged between the barrier layer and the first sublayer. The material of the first sublayer needs to be a material with high thermal conductivity.

[0018] In one embodiment, the cover and / or the first sublayer and / or the second sublayer are provided with a chemical resistant coating. The chemical resistant coating can prevent degradation of the cover and / or the first sublayer and / or the second sublayer.

[0019] In one embodiment, the cover and / or the first sublayer and / or the second sublayer are provided with an electrically insulating coating. This coating allows to easily isolate the housing from its environment.

[0020] In one embodiment, the first sublayer has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.3 mm. In one embodiment, the second sublayer has a thickness between 0.05 mm and 0.1 mm. The first sublayer and the second sublayer form a very thin laminate assembly.

[0021] In one embodiment, the barrier layer has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.3 mm. In one embodiment, the cover has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.2 mm. The housing system is very compact and can be adapted to the shape of the cover.

[0022] In one embodiment, the side wall and / or the bottom is provided with an outer layer comprising a plastic or metal material, wherein the outer layer is in surface contact with the conductive layer and / or the barrier layer. The outer layer can protect the barrier layer and the conductive layer. In addition, the outer layer can hold the barrier layer and the conductive layer together.

[0023] In one embodiment, the different layers are bonded together.

[0024] The present disclosure also relates to a battery cell, comprising a housing system as described above and a battery cell material having a side edge, wherein the battery cell material fits snugly within the recess and the side edge is in surface contact with the conductive layer. The battery cell material is in direct contact with the conductive layer. Heat can be transferred to the outside of the battery cell. In one embodiment, the cover is laser welded to the housing. Laser welding technology is easy to implement and provides a good seal of the cover on the housing. In another embodiment, the cover can be bonded to the housing. In another embodiment, the cover can be connected to the housing using a sheet bending process.

[0025] In one embodiment, the cover includes an emergency exhaust valve and positive and negative terminals.

[0026] In one embodiment, the battery cell materials include one or more cathodes, one or more anodes, an electrolyte, and a separator, and the cover includes a resealable opening to fill the electrolyte into the recess. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0028] Figure 1 A sectional view of a battery cell according to the invention with a housing system according to a first exemplary embodiment is shown;

[0029] Figure 2 A sectional view of a battery cell according to the invention with a housing system according to a second exemplary embodiment is shown;

[0030] Figure 3A and Figure 3B A schematic cross-sectional view of a third embodiment of a housing system for a battery cell according to the present invention is shown;

[0031] Figure 4A and Figure 4B A housing system without a cover and having a housing with an oval cross-section according to one embodiment is shown;

[0032] Figure 5A and Figure 5B A housing system without a cover and having a housing in a cylindrical shape is shown according to one embodiment;

[0033] Fig. 6A and Figure 6B A housing system without a cover and having a housing in the shape of a parallelepiped according to one embodiment is shown;

[0034] Figure 7 A possible structure of the barrier layer of the housing is schematically shown;

[0035] Fig. 8A and Figure 8B Two further possible exemplary embodiments of a barrier layer for the housing system according to the invention are shown. DETAILED DESCRIPTION

[0036] The same reference numbers in different drawings identify the same or similar elements.

[0037] Figure 1 , Figure 2 , Figure 3A , Figure 3B A battery cell 10 is shown. The battery cell 10 includes a battery cell material 12 and a housing system 14. The battery cell material is contained in the housing system. In other words, the housing system 14 seals and surrounds the battery cell material. As described above, in a known manner, the battery cell material includes one or more cathodes, one or more anodes, an electrolyte, and a separator, which is composed of a porous polymer or other suitable material to avoid direct contact between the electrodes.

[0038] The battery cell material 12 extends in a recess 16 of the housing system 14. More specifically, the housing system 14 includes a cover 18 and a housing 20. The housing includes a bottom and side walls. The bottom and side walls define the recess 16.

[0039] The housing 20 (more specifically, the bottom and the side walls) includes a conductive layer 22. The conductive layer 22 faces and defines the recess 16. The conductive layer 22 thus forms an inner layer (innermost layer). The conductive layer 22 may be in surface contact with the side edges of the battery cell material 12. The conductive layer 22 forming the bottom and the side walls may be integral. In another embodiment, the conductive layer may be made of two parts, one for the bottom and the other for the side walls, which are connected together by a sheet bending process, such as a process used in food, cosmetics, medicine and many other fields.

[0040] The side wall also includes a barrier layer 26. The barrier layer 26 is made of a low thermal conductivity material. More specifically, the barrier layer is made of one or more materials having thermal resistance and / or electrical resistance. For example, the barrier layer is made of a plurality of paper sheets 261, 262, 263. These paper sheets can be arranged to form an isolation gap 264 (e.g., a fluid gap, in particular an air gap). Figure 7 A possible arrangement of paper sheets forming the air gap is schematically shown. However, in other embodiments, the air gap 264 may have other shapes, or may be formed by other arrangements or layouts. Fig. 8A Another embodiment of the barrier layer 26 is shown, which includes an intermediate plate 262 and a plurality of spacers S, wherein the spacers S are arranged on both sides of the intermediate plate and extend from both sides of the intermediate plate. Figure 8BIn the embodiment, the barrier layer comprises several intermediate plates, each of which is separated by a spacer, so that an isolation gap, in particular an air gap, is formed between the plates. The total maximum thickness of the barrier layer is between 0.05 mm and 1 mm, more particularly 0.25 mm. The barrier layer 26 is only on the side walls. The bottom does not include the barrier layer 26. The entire barrier layer is made of paper, for example. For example, mica paper or aramid paper can be used. Mica paper called Micanite can also be used. The spacers can also be made of mica. For example Fig. 8A and Figure 8B It is obvious from the figure that the isolation gap is not an inherent parameter of the paper material, but is formed by the specific construction of the paper material. For example, the spacer together with the middle plate forms the isolation gap.

[0041] In a first embodiment of the housing system, Figure 1 As shown, the conductive layer 22 is made of metal. The metal can be, for example, copper, steel, aluminum, a steel alloy or an aluminum alloy. More specifically, the conductive layer is a copper layer. The copper layer can have a thickness between 0.1 mm and 1 mm. More specifically, the conductive layer 22 can have a thickness between 0.2 mm and 0.3 mm.

[0042] exist Figure 2 In the second embodiment shown, the conductive layer 22 includes a first sublayer 221 and a second sublayer 222. The first sublayer 221 is the innermost layer and directly faces the recess. The second sublayer on the sidewall is located between the barrier layer and the first sublayer 222. More specifically, the first sublayer is in surface contact with the second sublayer. The second sublayer is in surface contact with the barrier layer 26.

[0043] The first sublayer 221 is, for example, made of a material having a thermal conductivity greater than 5 W·m -1 ·K -1 The first sublayer 221 is made of any material that is chemically compatible with the battery cell material. For example, the first sublayer 221 is made of metal. The metal may be steel, aluminum, a steel alloy, or an aluminum alloy. The first sublayer 221 may have a thickness between 0.05 mm and 1 mm. More specifically, the conductive layer 22 may have a thickness of about 0.1 mm.

[0044] The second sub-layer 222 is made of a high thermal conductivity material. For example, a high thermal conductivity material may be considered to have a thermal conductivity between 100 and 3000 W·m -1 ·K -1The second sublayer 222 is made of, for example, a graphite material or copper or a copper alloy. The second sublayer 222 may have a thickness of 0.005 mm to 1 mm. For example, the second sublayer 222 may have a thickness of about 0.1 mm. The second sublayer 222 directly contacts the first sublayer 221 on one side and directly contacts the barrier layer 26 on the other side. For example, the first sublayer 221 and the second sublayer 222 may be bonded together. Some thin layers of dielectric glue or insulating materials may be used to electrically isolate the second sublayer 222.

[0045] exist Figure 3A and Figure 3B In the third embodiment shown, an outer layer 28 is provided. The outer layer 28 is provided around the barrier layer on the side wall. Figure 3A As shown, the outer layer 28 is in direct contact with the conductive layer on the bottom side. More specifically, as shown in FIG. Figure 3A As shown, the outer layer 28 directly contacts the second sub-layer 222. However, in another embodiment (not shown), the outer layer may directly contact the conductive layer 22 on the bottom side, the conductive layer being composed of a homogenous material, as described with respect to the first embodiment.

[0046] The bottom and side wall portions of the outer layer may be integral, or may be two separate parts.

[0047] In another possible embodiment, the outer layer 28 may be only a portion of the side wall, and the bottom does not include the outer layer 28 .

[0048] The outer layer 28 may be made of a plastic or metal material. The outer layer may have a thickness between 0.05 mm and 1 mm, in particular a thickness of about 0.1 mm.

[0049] The outer layer and / or the barrier layer and / or the conductive layer and / or the first sublayer and / or the second sublayer may be bonded together. In an alternative or complementary embodiment, the outer layer may be used to hold the conductive layer and the barrier layer together.

[0050] The conductive layer 22 and / or the outer layer 28 may be provided with a chemical resistant coating and / or an electrically insulating coating. The chemical resistant coating is, for example, an epoxy-based coating, a polyurethane-based coating, a phenolic resin-based coating or a fluoropolymer-based coating. The electrically insulating coating is, for example, a plastic-based paint.

[0051] The housing 20 cooperates with the cover 18. The cover 18 can be laser welded or bonded to the housing. More specifically, the cover is assembled to the housing 20 by sheet metal bending techniques. Sheet metal bending techniques are widely used in the food industry, particularly for the production of cans. The advantage of this process is that a mechanical process is used to assemble the cover and the housing. The housing and the cover are assembled in a sealed manner. The cover 18 is obviously flat and can be made of plastic or metal (e.g., steel or aluminum) material. The cover 18 can be provided with a chemical resistant coating and / or a resistive coating. The cover can have a thickness between 0.05 mm and 1 mm. In particular, the cover has a thickness between 0.1 mm and 0.2 mm.

[0052] The cover 18 includes a resealable opening 34 to fill the recess with electrolyte. The cover may also include a positive terminal 30 and a negative terminal 32. These terminals are connected to the positive and negative electrodes of the battery cell material, for example.

[0053] The cover 18 may also be provided with a venting device or emergency vent valve 36. The venting device may be adapted, for example, to achieve emergency venting in the event of a battery cell failure, and to achieve pressure differential compensation in a normal operating environment.

[0054] The bottom may be in direct contact with a cooling device or cooler (not shown) adapted to transfer heat from the battery cells. More specifically, the cooler is adapted to dissipate the heat transferred by the conductive layer. The cooler may be a passive cooler or an active cooler.

[0055] The housing system 14 thus produced is a lightweight housing suitable for preventing heat propagation and allowing for thermal management of the battery, thereby enhancing the performance of the battery subassembly.

[0056] A battery cell with such a housing system may have an overall height H between 10 and 300 mm. The width w of the subassembly may be between 5 and 100 mm. The length L of the subassembly 20 may be between 10 and 1000 mm.

Claims

1. A housing system (14) for a battery cell, in particular for a prismatic or cylindrical battery cell, the housing system (14) defining a recess (16) for receiving battery cell material, the housing system comprising: - a cover (18), and - a housing (20), wherein the cover and the housing cooperate to define the recess, The housing comprises a bottom and a side wall, wherein the sidewalls and the bottom include a conductive layer (22) containing a metallic material, the conductive layer directly defining the recess, The side wall further comprises a barrier layer (26) made of a barrier material, wherein the barrier layer surrounds the conductive layer and makes surface contact with the conductive layer, and the bottom portion does not have the barrier layer, and wherein the thermal resistance of the barrier layer is higher than the thermal resistance of the conductive layer, It is characterized in that the barrier layer comprises an intermediate plate (262), and a plurality of isolation gaps are arranged on both sides of the intermediate plate.

2. The housing system (14) according to claim 1, wherein: The isolation gap is an air gap.

3. The housing system (14) according to claim 2, wherein: The barrier layer (26) comprises a plurality of paper sheets (261, 262, 263), and wherein the paper sheets are arranged to form the air gap (264).

4. The housing system according to any one of claims 1 to 3, wherein: The conductive layer is made of copper material.

5. The housing system according to any one of claims 1 to 3, wherein: The conductive layer includes a first sub-layer made of a first sub-layer material and a second sub-layer made of a second sub-layer material different from the first sub-layer material.

6. The housing system according to claim 5, wherein: The first sublayer material is steel or aluminum, and the second sublayer material is graphite, and wherein on the side wall, the second sublayer is arranged between the barrier layer and the first sublayer.

7. The housing system (14) according to claim 5 or 6, wherein: The cover and / or the first sublayer are provided with a chemically resistant coating and / or an electrically insulating coating.

8. The housing system (14) according to any one of claims 5 to 7, wherein: The first sublayer (221) has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.3 mm, and wherein the second sublayer (222) has a thickness between 0.05 mm and 0.1 mm.

9. The housing system according to any one of claims 1 to 8, wherein: The side wall and / or the bottom is provided with an outer layer (28) comprising a plastic or metal material, wherein the outer layer is in surface contact with the conductive layer and / or the barrier layer.

10. The housing system (14) according to any one of claims 1 to 9, wherein: The barrier layer (26) has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.3 mm.

11. The housing system (14) according to any one of claims 1 to 10, wherein: The cover has a thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.2 mm.

12. A battery cell (10), comprising a housing system (14) according to any one of claims 1 to 11 and a battery cell material (12) having side edges, wherein: The battery cell material fits snugly into the recess, and the side edges make surface contact with the conductive layer.

13. The battery cell (10) according to claim 12, wherein: The cover (18) is assembled onto the housing (20) by means of a sheet metal bending process.

14. The battery cell (10) according to claim 12 or 13, wherein: The cover includes an emergency exhaust valve and positive and negative terminals.

15. The battery cell (10) according to any one of claims 12 to 15, wherein: The battery cell material (12) includes one or more cathodes, one or more anodes, an electrolyte and a separator, and wherein the cover includes a resealable opening to fill the electrolyte into the recess.

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