WO2018101695A1

WO2018101695A1 - Wall structure of battery cell, battery sub-module, battery module, or battery system

Info

Publication number: WO2018101695A1
Application number: PCT/KR2017/013641
Authority: WO
Inventors: 고루브코브안드레
Original assignee: 삼성에스디아이 주식회사
Priority date: 2016-11-29
Filing date: 2017-11-28
Publication date: 2018-06-07

Abstract

A wall structure according to one embodiment of the present invention is a wall structure of a case of one of a battery cell, a battery sub-module, a battery module, and a battery system, and comprises a multilayer structure having a first layer facing the inside of the case, a third layer facing the outside of the case, and a second layer arranged between the first layer and the third layer, wherein the first layer is configured so as to electrically insulate the second layer from the inside of the case, the second layer includes an ablative material and is configured so as to thermally shield the third layer, and the third layer has a heat conductivity higher than that of the second layer.

Description

Wall structure of a battery cell, battery submodule, battery module, or battery system

The present invention relates to a wall structure of one of a battery cell, battery submodule, battery module or battery system, in particular a wall structure comprising a multilayer structure. The present invention also relates to battery cells, battery submodules, battery modules and battery systems having a multilayer wall structure and having improved heat dissipation properties and improved resistance to electric arcs.

Rechargeable or secondary batteries are different from primary cells that only irreversibly convert chemicals into electrical energy in that charging and discharging can be repeated. Low capacity secondary batteries are used as power sources for small electronic devices such as cellular phones, notebook computers and camcorders, and high capacity secondary batteries are used as power sources for hybrid vehicles and the like.

In general, the secondary battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a case accommodating the electrode assembly, and an electrode terminal electrically connected to the electrode assembly. Electrolyte is injected into the case to enable charging and discharging of the battery through the electrochemical reaction of the positive electrode, the negative electrode and the electrolyte. The shape of the case, for example cylindrical or rectangular, depends on the use of the cell.

The secondary battery may be used as a battery module formed of a plurality of unit battery cells coupled in series and / or in parallel to provide a high energy density. For example, it can be used to drive a motor of a hybrid vehicle. That is, the battery module is formed by interconnecting the electrode terminals of the plurality of unit battery cells according to the amount of power required, for example, may be formed to implement a high power secondary battery for an electric vehicle.

The battery module may be of block design or modular design. In the block design, each cell is coupled to a common current collector structure and a common battery management system, and the unit is housed in a case. In a modular design, a plurality of battery cells are connected to form a submodule, and several submodules are connected to form a module. The battery management function may be implemented at least partially at the module or submodule level, thereby improving compatibility. One or more battery modules are mechanically and electrically integrated to form a battery system, equipped with a thermal management system, and configured to communicate with one or more electricity consumers.

Mechanical integration of the battery system requires the proper mechanical connection of the individual components (for example components of the battery submodules, between the submodules, the consumer of electricity, for example the structure of a system providing a vehicle). Such a connection should be designed to maintain and store its function during the life of the battery system and under stress generated during use. At the same time, space and interoperability requirements must be met (especially mobile devices).

Mechanical integration of the battery module can be accomplished by providing a carrier plate, for example a bottom plate, and placing individual battery cells or submodules thereon. Fastening the battery cells or submodules can be achieved, for example, by fitting into recesses in the carrier plate, by mechanical fastening means such as bolts or screws, or by constraining the battery cells or submodules. Restraint may be achieved by securing the side plate to the side of the carrier plate and / or providing another carrier plate to secure the first carrier plate and / or the side plate. Thus, a multi-level battery module can be constructed, wherein the carrier plate and / or side plate can include a coolant duct for cooling the battery cell or submodule.

Mechanical integration of the battery submodules can be achieved by using mechanically reinforced electrical connectors or by fixing the battery cells to the carrier beam or strut to the electrical connectors. Additionally or alternatively, the submodule may include individual casings that cover some or all of the surfaces of the plurality of aligned battery cells. Such battery submodules are arranged in a battery module, for example, on a carrier plate in a separate casing.

The battery submodule, battery module and / or battery system may comprise a component for constraining its components, ie a battery cell, battery submodule or battery module. On the one hand the case must provide protection from environmental influences, for example mechanical, thermal or electrical shocks. It must also protect the environment from the dangerous effects of one or more malfunctioning battery cells. At the battery cell level, the case generally includes a metal or plastic case that ensures mechanical protection, electrical insulation and heat dissipation. For some cell types, flexible pouches may be used instead of hard cylindrical or rectangular cans. The case or pouch generally includes a metal layer to provide mechanical strength and heat distribution, and may further include an electrically insulating coating on the inner or outer surface of the metal layer. Pouches according to the prior art are disclosed in prior art US 2006/0083984 A1, and battery cases according to the prior art are disclosed in KR 20080049548 A1.

At the battery submodule, battery module and battery system level, the housing is typically provided in a metal or plastic case made of a metal plate, a fiber reinforced polymer or an injection molded aluminum shell. The case must provide mechanical reinforcement and may include an electrically insulating coating. Since an increase in internal temperature can cause abnormal reactions occurring in one or more battery cells, the metal case can be further configured to efficiently radiate, dissipate and / or dissipate heat generated therein to the outside. In order to provide sufficient heat dissipation, the case generally has a relatively low wall strength, which reduces the weight of the case.

However, relatively thin walls of the case of a battery cell, battery submodule, battery module or battery system may be melted by locally increased temperatures, for example due to one or more battery cells malfunctioning. In particular, a malfunctioning battery cell can cause an electric arc that causes a sharp temperature rise within a small area of the case when it strikes the case. This arc can thus damage the case and ultimately break the case. Hazardous gases can then leak out of the damaged case and be toxic to the user (eg a car), or the gas may ignite causing further damage.

One aspect of the present invention provides a wall structure of a case of one of a battery cell, a battery submodule, a battery module, or a battery system, and provides a wall structure of a case having improved heat dissipation characteristics and improved resistance to electric arcs. will be.

One aspect of the present invention relates to a wall structure of one case selected from the group comprising a battery cell, a battery submodule, a battery module and a battery system. The wall structure includes a multilayer structure having a first layer facing the inside of the case, a third layer facing the outside of the case, and a second layer disposed between the first layer and the third layer. In other words, the first layer, the second layer and the third layer are disposed adjacent to or above each other in ascending order. Additional layers may be disposed on or between the first, second and third layers so aligned. According to one embodiment of the invention, the first layer is configured to electrically insulate the second layer from the interior of the case. That is, the first layer can be an electrically insulating layer comprising an electrically insulating material. The second layer comprises an ablative material and is configured to heat shield the third layer. That is, the second layer is a heat insulating layer comprising a thermally insulating material and may be configured to delay heat transfer from the inside (or first layer) of the case to the outside (or third layer) of the case. The third layer has a higher thermal conductivity than the second layer. Thus, the third layer is configured to distribute any heat transferred from the inside of the case to a large area of the third layer (outside of the case).

Another aspect of the invention relates to a battery cell comprising an electrode assembly, a case for receiving the electrode assembly and a cap assembly for sealing the opening of the case. The bottom and / or sidewalls of the case and / or cap assembly comprise a multilayer structure. The multilayer structure includes a first layer facing the inside of the battery cell, a third layer facing the outside of the battery cell, and a second layer disposed between the first layer and the third layer. In other words, the first layer, the second layer and the third layer are disposed adjacent to or above each other in ascending order. Additional layers may be disposed on or between the first, second and third layers so aligned. According to one embodiment of the invention, the first layer is configured to electrically insulate the second layer from the electrode assembly. That is, the first layer can be an electrically insulating layer comprising an electrically insulating material. The second layer comprises a heat resistant material and is configured to heat shield the third layer. That is, the second layer is a heat insulating layer comprising a thermally insulating material and may be configured to delay heat transfer from the inside of the battery cell to the outside of the battery cell. The third layer has a higher thermal conductivity than the second layer. Thus, the third layer is configured to distribute any heat transferred from the inside of the battery cell to the large area of the third layer.

Another aspect of the invention relates to a battery submodule comprising a plurality of aligned battery cells and a battery submodule case. In this case, the battery submodule case has a pair of submodule front plates connected to a plurality of submodule side plates facing each other. The battery submodule case houses a plurality of aligned battery cells. The submodule front plate and / or the submodule side plate may include a first layer facing a plurality of battery cells, a third layer facing the outside of the battery submodule case, and a second layer disposed between the first layer and the third layer. It includes a multi-layer structure having a. In other words, the first layer, the second layer and the third layer are disposed adjacent to or above each other in ascending order. Additional layers may be disposed on or between the first, second and third layers so aligned. According to one embodiment of the invention, the first layer is configured to electrically insulate the second layer from the plurality of battery cells. That is, the first layer can be an electrically insulating layer comprising an electrically insulating material. The second layer comprises a heat resistant material and is configured to heat shield the third layer. That is, the second layer is a heat insulating layer including a heat insulating material, and may be configured to delay heat transfer from the inside of the battery sub module case to the outside of the battery sub module case. The third layer has a higher thermal conductivity than the second layer. Thus, the third layer is configured to distribute any heat transferred from the inside of the battery submodule case to a wide area (or outside of the battery submodule case) of the third layer.

Another aspect of the invention relates to a battery module comprising a plurality of battery cells and / or a plurality of battery submodules disposed in (or on) a battery module case having a bottom plate. The bottom plate or other sidewall of the battery module case includes a multilayer structure. The multilayer structure includes a first layer facing a plurality of battery cells and / or a plurality of battery submodules, a third layer facing the outside of the battery module case, and a second layer disposed between the first layer and the third layer. It includes. In other words, the first layer, the second layer and the third layer are disposed adjacent to or above each other in ascending order. Additional layers may be disposed on or between the first, second and third layers so aligned. According to one embodiment of the invention, the first layer is configured to electrically insulate the second layer from the plurality of battery cells and / or the plurality of battery submodules. That is, the first layer can be an electrically insulating layer comprising an electrically insulating material. The second layer comprises a heat resistant material and is configured to heat shield the third layer. That is, the second layer is a heat insulating layer including a heat insulating material, and may be configured to delay heat transfer from the inside of the battery module case to the outside of the battery module case. The third layer has a higher thermal conductivity than the second layer. Thus, the third layer is configured to distribute any heat transferred from the inside of the battery module case to a wide area (or outside of the battery module case) of the third layer.

Another aspect of the invention relates to a battery system comprising a plurality of battery cells and / or a plurality of battery submodules and / or at least one battery module, and a battery system case. The side wall of the battery system case includes a first layer facing a plurality of battery cells and / or a plurality of battery submodules and / or at least one battery module, a third layer facing an outside of the battery system case, and a first layer; And a multilayer structure having a second layer disposed between the third layers. In other words, the first layer, the second layer and the third layer are disposed adjacent to or above each other in ascending order. Additional layers may be disposed on or between the first, second and third layers so aligned. According to one embodiment of the invention, the first layer is configured to electrically insulate the second layer from the plurality of battery cells and / or the plurality of battery submodules and / or at least one battery module. That is, the first layer can be an electrically insulating layer comprising an electrically insulating material. The second layer comprises a heat resistant material and is configured to heat shield the third layer. That is, the second layer is a heat insulating layer comprising a thermally insulating material and may be configured to delay heat transfer from the inside of the battery system case to the outside of the battery system case. The third layer has a higher thermal conductivity than the second layer. Thus, the third layer is configured to distribute any heat transferred from the inside of the battery system case to a wide area (or outside of the battery system case) of the third layer.

A case of a battery cell, submodule, module or system having a multilayer structure according to an embodiment of the present invention can withstand an electric arc inside the case. The multilayer structure consists of at least three layers, where the first layer faces the inner surface of the case and can be exposed to an arc inside the case in case of failure. The first layer is an electrical insulation layer to prevent shorting of additional components inside the case that are far away from the arc impinging on the case. To prevent the arc from breaking the case, the second layer is a heat shield layer comprising a heat resistant material. Physically, the heat resistant material is configured to dissipate large amounts of thermal energy by sacrificing the material. Multiple physical processes may participate in such high efficiency heat dissipation such as carbonization and pyrolysis. The second layer can further include low thermal conductivity. The third layer is configured to provide sufficient mechanical stability to the case and may be the same as the case of a conventional battery cell, submodule, module or system. In order to further prevent the third layer from becoming mechanically unstable, the third layer has a higher thermal conductivity than the thermal conductivity of the second layer to distribute any heat passing through the second layer to the large surface area of the third layer. Has This reduces the peak temperature and the risk of softening or melting of the third layer.

According to an embodiment of the invention, the heat resistant material of the second layer is configured to transition to an ablation process at a critical temperature of 600 ° C. or less, preferably 500 ° C. or less, particularly preferably 400 ° C. or less. The ablation process may include various physical processes that occur in response to ablation material reaching a critical temperature. The process may include phase changes such as melting, evaporation and sublimation; Thermal conduction and heat storage of a heat resistant material matrix; Thermal convection in the liquid layer; Evaporation of gases and liquids and heat absorption from the surface to the boundary layer and endothermic chemical reactions. The type of heat resistant material thus occurs according to the prevailing ablation mechanism, but other mechanisms may still be present in the material. There are typically three main types of ablators in the art, namely sublimation or melting ablators, charring ablators, and intumescent ablators.

Inflatable ablators are characterized by bubbles starting to rise above the critical temperature. The sudden increase in volume associated with the foam is difficult to handle in the case structure and can lead to breakage of the case itself. Thus, the molten and carbonized ablators may be the preferred materials for the wall structure according to the present invention. In carbonization ablators, thermal energy is dissipated mainly due to endothermic reactions. Here, the main part of the heat resistant material is kept solid. Thus, carbonization ablation is particularly preferred for the wall structure according to the invention, but can be used in combination with a molten ablation as a reinforcing material.

The second layer may be completely enclosed between the first layer and the third layer. In particular, the second layer can be completely sealed between the first layer and the third layer in an airtight manner. This can be realized by completely covering the entire surface of the case with the first layer, the second layer and the third layer. Optionally, the second layer may be partially disposed on the surface of the first layer and the third layer may be disposed on the entire surface of the first layer and the second layer. Thus, in the peripheral region of the multilayer structure, the first layer can be in direct contact with the third layer to cover the second layer in an airtight manner. By covering the second layer, it is possible to avoid ignition of the oxidation process and / or ablation gas at temperatures above the critical temperature or decomposition temperature. Thus, completely covering the second layer by the first and third layers may be a prerequisite for initiating carbonization and / or pyrolysis of the carbonization ablation. Multi-layer structure according to an embodiment of the present invention, the first step of providing a third layer to the case of each conventional structure (cell, submodule, module, system), the second layer on the inner surface of the third layer The second step of depositing, and the third step of depositing the first layer inside the second layer can be produced.

According to an embodiment of the present invention, the heat resistant material comprises a carbonization ablator having a decomposition temperature of 600 ° C. or lower, preferably 500 ° C. or lower, particularly preferably 400 ° C. or lower. In other words, the carbonization and / or pyrolysis of the carbonization ablation can be initiated at the decomposition temperature. Due to this low decomposition temperature, melting or destabilization of the third layer consisting of or comprising aluminum can be reliably prevented. Here, decomposition refers to the reaction temperature at which endothermic chemical decomposition begins to occur. This causes the organic substrate of the pure heat resistant material to pyrolyze into a carbonaceous material and some gaseous products in the decomposition zone. As a result, char (carbonaceous material produced during carbonization) is produced from an organic substrate. The decomposition zone separates the pure material from the carbonization zone and passes through the heat resistant material through the boundary layer. The passage of the boundary layer improves insulation and reduces convective heat transfer. In addition, ablation gas impedes radiant heat transfer. Thus, the heat resistant material acts as a heat sink that absorbs almost all incident heat fluxes.

The heat resistant material of the second layer is configured to transition to an ablation process, preferably to endothermic decomposition such as carbonization and pyrolysis in response to an electric arc impinging on the first layer. The electric arc may comprise a high temperature plasma having a temperature between 5000 K and 50,000 K defined by a very small volume. Thus, the heat resistant material of the second layer can also be configured to transition to the ablation process at higher temperatures, for example at least 5000K, at least 10,000K or at least 15,000K. Electric arcs inside a case, such as a battery, randomly collide with a very small surface area inside the case, and the likelihood of the electric arc repeatedly colliding at the same point is somewhat less. Thus, the local sacrifice of the heat resistant material in response to the impact arc does not significantly change the mechanical stability of the second layer. Thus, the second layer as a whole remains mechanically stable during and after arcing in the case. The third layer includes higher thermal conductivity than the second layer. Thus, the locally increased temperature at the point of impact is distributed over a large area of the third layer, and the third layer as a whole remains mechanically stable in case of electrical arc generation inside the case. Thus, an extended lifetime can be realized using the wall structure according to the embodiment of the present invention. However, the case may be replaced after a single failure and internal arcing.

According to an embodiment of the present invention, the heat resistant material is graphite, carbon-fiber-reinforced phenolic, epoxy resin, silicone elastomers, Teflon, quartz ( one or more (composite) of quartz, cork and / or nylon. Preferably silicone elastomers, in particular foamed silicone elastomers, can be used as the heat resistant material of the second layer. Such carbide ablation materials may be used in combination with sublimation or melt reinforcement materials. In particular, the substrate or resin of the carbonization ablator is filled with particles or fibers of the molten ablator. Silicone elastomers or phenolic materials may be used as the base material. In particular, the expanded silicone elastomer is filled with silicon dioxide and iron oxide. These materials decompose into similar foams of SiO ₂ , SiC and FeSiO ₃ .

Or instead, the carbonized ablation material can be filled with silica or nylon to provide cooling through evaporation. Carbon fiber reinforced phenolic materials are also preferred for the heat resistant materials of the second layer. By way of example, the heat resistant material may comprise a low density epoxy-novolac resin with phenolic microballon and silica fiber reinforcement to implement a second, lightweight layer. In addition, graphite (graphite fiber) reinforced epoxy composites can be used as cost effective and low density heat resistant materials. Cork can also be used as a heat resistant material and glass or mineral particles can be embedded in a substrate of heat resistant material such as a silicon substrate. In particular, a silicone resin comprising particles of cork, glass and phenolic microballoons can be used as the heat resistant material of the second layer.

According to an embodiment of the invention, the third layer comprises a metal or a metal alloy. In particular, the third layer is an alloy of aluminum, iron (Fe), carbon (C), chromium (Cr) and manganese (Mn) and / or iron (Fe), carbon (C), chromium (Cr) and nickel (Ni). ) Alloys. Thus, the third layer may be the same as a case of a conventional battery or the like. The third layer of metal has good thermal conductivity and thus evenly distributes the heat generated by the spatially limited electric arc over a large area. Depending on the field of use, for example. In the case of a battery system or a battery system comprising several hundred cells, the third layer has a thickness that ensures that the third layer is not easily weakened in response to the increased temperature. Thus, the third layer can withstand the overpressure of the gas generated inside the case such as a battery.

In addition, a thermally conductive plastic material or resin can be used for the third layer. The material system suitable for the third layer is the same or similar to the material system suitable for the conventional battery case. The third layer provides mechanical fixation of the cell components, mechanical protection of the main components in the event of a collision, protection from the environment (humidity and dust), EMC shielding, heat distribution in the case of hotspots, containment of gases that can be generated from the cell And mechanical integrity of the case.

According to an embodiment of the invention, the first layer comprises a fiber reinforced plastic material and is configured to mechanically protect the second layer. The first layer can have electrical insulation, ductility and heat resistance. Since the first layer is electrically insulating, a short circuit will not occur if a conductive component inside the case, for example a bus bar, deforms toward the case and contacts the case. Thus, the second layer is configured to provide mechanical protection of the second layer and to prevent short circuits when the bus bar contacts the interior of the case. Depending on the field of use, for example, in a case of a battery system or a battery system comprising several hundred cells, the first layer has a thickness such that the second layer can reliably insulate the voltage occurring inside the case.

The multilayer wall structure according to an embodiment of the present invention is an essential part of a battery case or a cap assembly for sealing an opening of the battery case for accommodating the electrode assembly. According to an embodiment of the invention, the first layer is configured to electrically insulate the second layer from the electrode assembly. In this case, the first layer may have a thickness of 20 μm to 50 μm, the second layer may have a thickness of 100 μm to 1 mm, and the third layer may have a thickness of 200 μm to 2 mm.

Further, the multilayer wall structure according to the embodiment of the present invention is an essential part of the battery submodule case. The battery sub module case includes a pair of sub module front plates that receive a plurality of aligned battery cells and face each other and are connected to the plurality of sub module side plates. The first layer is configured to electrically insulate the second layer from the plurality of battery cells. In this case, the first layer may have a thickness of 20 μm to 200 μm, the second layer may have a thickness of 400 μm to 4 mm, and the third layer may have a thickness of 0.5 mm to 2 mm.

Further, the multilayer wall structure according to the embodiment of the present invention is an essential part of a battery module case for accommodating a plurality of battery cells and / or a plurality of battery submodules. The battery module case includes a bottom plate, and the multilayer wall structure may be an integral part of the bottom plate. The first layer is configured to electrically insulate the second layer from the plurality of battery cells and / or battery submodules. At this time, the first layer may have a thickness of 50 μm to 1 mm, the second layer may have a thickness of 1 mm to 5 mm, and the third layer may have a thickness of 2 mm to 10 mm.

In addition, the multilayer wall structure according to an embodiment of the present invention is an essential part of a battery system case accommodating a plurality of battery cells and / or a plurality of battery submodules and / or at least one battery module. The first layer is configured to electrically insulate the second layer from the plurality of battery cells and / or battery submodules and / or at least one battery module. At this time, the first layer may have a thickness of 50 μm to 2 mm, the second layer may have a thickness of 1 mm to 10 mm, and the third layer may have a thickness of 2 mm to 50 mm.

According to one embodiment of the present invention, at least one of the battery cell, the battery submodule, the battery module or the battery system has a multi-layered wall structure, thereby having improved heat dissipation characteristics and improved resistance to electric arcs.

1 is a schematic perspective view of a battery cell according to an embodiment of the present invention.

2 is a schematic cross-sectional view of a battery cell including a multilayer wall structure according to an embodiment of the present invention.

3 is a schematic perspective view of a battery submodule including a multilayer wall structure according to an embodiment of the present invention.

4 is a schematic perspective view of a battery module case including a multilayer wall structure according to an embodiment of the present invention.

5 is a schematic perspective view of a battery system including a multilayer wall structure in accordance with one embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected", but also "indirectly connected" between other members. In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

Also in this specification, the term 'and / or' includes any combination of the plurality of listed items or any of the plurality of listed items. That is, in the present specification, the description 'A and / or B' may include 'A or B' as 'A', 'B', or 'A and B'.

Also in this specification, terms such as 'first', 'second' and the like are used to describe various components, regions, layers and / or sections, but these components, regions, layers and / or sections are those terms. It is not limited to. When a portion of a layer, film, region, plate, or the like is said to be "on" or "on" another portion, this includes not only when the other portion is "right over" but also when there is another portion in the middle. Also, when a portion of a layer, film, region, plate, etc. is said to be "below" or "below" another part, this includes not only the other part "below" but also another part in the middle. do.

1 is a perspective view of a battery cell according to an embodiment of the present invention, Figure 2 is a cross-sectional view along the IV-IV line of FIG.

1 and 2, referring to FIGS. 1 and 2, a battery cell 80 according to an embodiment of the present invention includes an electrode assembly 10 and an electrode assembly 10 including an electrolyte solution. It includes a case 26 for receiving. The battery cell 80 may also include a cap assembly 30 to seal the opening of the case 26. The battery cell 80 is described as an example of a lithium ion secondary battery configured in a prismatic form, but is not limited thereto.

The electrode assembly 10 may be formed as a jelly roll type electrode assembly by spirally winding the anode 11 and the cathode 12 with the separator 13 therebetween. The positive electrode 11 and the negative electrode 12 may each include a coating area of a current collector formed of a thin metal foil on which an active material may be coated, and the active material may be disposed on the positive and negative electrode uncoated portions 11a and 12a of the current collector. It may not be coated.

The positive electrode non-coating portion 11a may be formed at one end in the longitudinal direction of the positive electrode 11, and the negative electrode non-coating portion 12a may be formed at one end in the longitudinal direction of the negative electrode 12. The electrode assembly 10 may have a structure including a plurality of sheets in which the anode 11, the separator 13, and the cathode 12 are repeatedly stacked.

The electrode assembly 10 may be accommodated in the case 26 together with the electrolyte. The electrolyte may be made of a lithium salt such as LiPF 6 or LiBF 4 using organic solvents such as EC, PC, DEC, EMC, EMC, and the like. The electrolyte can be in liquid, solid or gel state. The case 26 may be configured in a substantially rectangular parallelepiped shape, and an opening may be formed in one surface.

The case 26 may comprise a substantially rectangular bottom surface 27, and may include a pair of first sidewalls (or wide sides) 18, 19 and a pair of second sidewalls 16, 17 (or Narrow side) and may form a space for accommodating the electrode assembly 10. The

first sidewalls

18 and 19 may be formed to face each other, and the

second sidewalls

16 and 17 may be disposed to face each other. An edge length at which the bottom surface 27 and the

first sidewalls

18 and 19 are connected to each other may be longer than an edge length at which the bottom surface 27 and the

second sidewalls

16 and 17 are connected to each other. The first and second sidewalls that are adjacent to each other may be surrounded by each other at an angle of 90 °.

The cap assembly 30 may include a cap plate 31 coupled to the case 26 to cover the opening of the case 26, and may be provided outside the case 26 to protrude from the cap plate 31. It may include a positive electrode terminal 21 and the negative electrode terminal 22 which is formed to be electrically connected to the positive electrode 11 and the negative electrode 12, respectively. The cap plate 31 may include an inlet 32 and a vent hole 34 in communication with the interior of the cap assembly 30. The injection hole 32 may be formed to enable the injection of the electrolyte, and the sealing cap 38 may be installed on or in the injection hole 32. In addition, the vent hole 34 may be equipped with a vent member 39 having a notch 39a formed therein that may be opened by a predetermined pressure.

The positive terminal 21 may be electrically connected to the positive electrode 11 through the current collecting tab 41, and the negative terminal 22 may be electrically connected to the negative electrode 12 through the current collecting tab 42. A sealing gasket 59 may be mounted between the terminal connection member 25 and the cap plate 31. The lower insulating member 43 into which the lower portion of the terminal connection member 25 is inserted may be installed below the cap plate 31. The connecting plate 58 for electrically connecting the positive terminal 21 and the cap plate 31 may be mounted between the positive terminal 21 and the cap plate 31.

The negative electrode terminal 22 and the current collecting tab 42 may be electrically connected to each other. A sealing gasket similar to the gasket 59 described above may be mounted between the negative electrode terminal 22 and the cap plate 31. An upper insulating member 54 for electrically insulating the negative terminal 22 and the current collecting tab 42 from the cap plate 31 may be mounted between the negative terminal 22 and the cap plate 31.

As shown in FIG. 2, the sidewall 29 of the battery case 26 may include a multilayer structure 60 according to an embodiment of the present invention. In addition, the bottom surface 27 or the cap assembly 30 may also include a multilayer structure 60 according to an embodiment of the present invention. Here, the sidewall 29 includes the

first sidewalls

18 and 19 and the

second sidewalls

16 and 17 of the battery cell case 26, which will be collectively described as the sidewall 29.

As shown in FIG. 2, the sidewall 29 includes a first layer 61 facing the inner side 64 of the sidewall 29 and facing the electrode assembly 10. The first layer 61 is an electrically insulating material such as cast polypropylene (CPP) and may be 25 μm thick. The first layer 61 is configured to isolate subsequent layers of the multilayer structure 60 from the electric arc or spark generated inside the case 26 by the electrode assembly 10.

The multilayer structure 60 further includes a third layer 63 facing the outer side 65 of the battery cell 80. The third layer 63 may be made of aluminum and have a thickness of 0.8 mm, providing mechanical stability to the battery cell case 26. In particular, the third layer 63 is configured to withstand the pressure inside the battery cell 80 below the threshold pressure for actuating the vent member 39. In addition, the third layer 63 has a high thermal conductivity.

The multilayer structure 60 further includes a second layer 62 completely surrounded between the first layer 61 and the third layer 63 and comprising an ablative material. The second layer 62 comprises a nylon resin matrix comprising nylon particles disposed in a matrix and having a thickness of 0.5 mm. The second layer 62 is configured to transition to an ablation process at a critical temperature of about 400 ° C. Thus, at temperatures above 400 ° C., the heat resistant material will pyrolyze and begin to change into a char (carbonaceous material produced during carbonization) to protect the third layer 63.

Referring to FIG. 3, a battery submodule 90 according to an embodiment of the present invention includes a plurality of aligned secondary battery cells 80 having a planar shape illustrated in FIGS. 1 and 2. The battery cells 80 are aligned with the

first side

18, 19 of adjacent battery cells 80 facing each other. The pair of submodule front plates 91 are mechanically coupled to the pair of submodule side plates 92 facing the second side surfaces 16, 17 of the battery cell 80. The submodule front plate 91 and the submodule side plate 92 constitute a case 93 of the battery submodule 90. The positive terminal 21 and the negative terminal 22 of the adjacent battery cell 80 may be electrically connected through a bus bar (not shown). Accordingly, the battery submodule 90 may be used as a power source unit by electrically connecting the plurality of battery cells 80 as one bundle.

As shown in FIG. 3, the submodule side plate 92 includes a multilayer structure 60 according to an embodiment of the invention. In addition, the sub-module front plate 91 may also include a multilayer structure 60. The multilayer structure 60 includes a first layer 61 opposite the inner side 64 of the submodule side plate 92 and the narrow sidewalls (second sidewalls 16, 17) of the aligned battery cell 80. . The first layer 61 is made of an electrically insulating plastic material such as polyamide or polypropylene and may have a thickness of 0.1 mm. Thus, the first layer 61 can have a thickness that can electrically insulate subsequent layers (second, third layers: 62, 63) from an electric arc generated by one or more aligned battery cells 80. have. Multilayer structure 60 is a thermally conductive polymer, or a thermally conductive sheet material such as steel or aluminum, and includes a third layer 63 having a thickness of 1 mm. Thus, the third layer 63 is configured to mechanically stabilize the plurality of battery cells 80 and to prevent external environmental impact.

The second layer 62 is completely enclosed between the first layer 61 and the third layer 63 and is a graphite (or graphite fiber) reinforced epoxy composite having a thickness of 2 mm as a heat resistant material. ) May be included. Since the melting temperature of the third layer 63 is approximately 600 ° C., the second layer 62 transitions to an ablation process, for example carbonization of the epoxy composite, at a critical temperature sufficiently lower than the melting temperature. Thus, the second layer 62 is configured to heat shield the third layer 63 from an electric arc impinging on the first layer 61.

The plurality of battery submodules 90 illustrated in FIG. 3 may be disposed in a case 96 (see FIG. 4) of the battery module to form a battery module. 4 is a diagram of an embodiment of a battery module case 96 including a bottom plate 97 on which a battery cell 80 is to be placed. In particular, the bottom plate 97 includes a plurality of assembly regions 98 in which one battery submodule 90 is arranged in each assembly region 98. The bottom plate 97 may further include a cooling tube 99 integrally embedded in the bottom plate 97. The side wall or the bottom plate of the battery module case 96 may include a multilayer structure 60 according to an embodiment of the present invention.

As shown in FIG. 4, the side wall of the battery module case 96 has a multi-layer structure 60 according to an embodiment of the present invention having a first layer 61 facing the inner side 64 of the battery module case 96. ). The first layer 61 may have a thickness of 1 mm to provide sufficient electrical insulation against electrical arcs that may be generated by one or more failed cells of the battery module. The third layer 63 may be made of cast aluminum having a thickness of 0.7 cm and facing the outer side 65 of the battery module case 96. At this time, the thickness may be determined to be a thickness sufficient to provide mechanical stability to the plurality of battery cells and / or battery submodules disposed in the assembly region 98. The cooling tube 99 may be embedded in the third layer 63. The second layer 62 is completely enclosed by the first layer 61 and the third layer 63 and is a substrate of a charring ablative material containing nylon fibers which is a melting ablator. Silicone resins. The second layer 62 may have a thickness of 4 mm to provide sufficient heat shielding against electric arcs that may be generated by one or more failed cells of the battery module.

Referring to FIG. 5, a battery system 100 according to an embodiment of the present invention includes a plurality of battery submodules 90 illustrated in FIG. 3. Four rows of battery submodules 90, each containing nine battery submodules 90, are disposed in a case 101 of the battery system 100. The battery system case 101 may include a sidewall 102, a bottom plate 103 welded to the sidewall 102, and a cover (not shown). The battery system 100 includes a first and / or second electrical and electronic box (E / E box, not shown) for controlling the voltage and current of the battery submodule 90. The electrical and electronic box may include a battery management unit (BMU), a high voltage connector, an input, a fuse, a relay, a current sensor, an EMC-filter, a precharge relay, a resistor, and / or an HV interface.

The at least one sidewall 102, the bottom plate 103, or the cover (not shown) of the battery system case 101 may include a multilayer structure 60 according to an embodiment of the present invention.

As shown in FIG. 5, at least one sidewall 102, preferably each sidewall 102 of the battery system case 101, is an inner side 64 of the battery system case 101 and a plurality of battery submodules. And a first layer 61 facing 90. The first layer 61 is made of a mixture of ceramic particles and an adhesive resin as an electrically insulating material, and may have a thickness of 2 mm. Thus, the first layer 61 is configured to electrically shield the second layer 62 and the third layer 63 from the electric arc generated by the one or more malfunctioning battery submodules 90. The third layer 63 of the multilayer structure 60 is made of extruded aluminum profile facing the outside of the battery system case 101 and having a thickness of 2 cm. Accordingly, sidewall 102 is suitable for being assembled into battery system case 101 to provide mechanical integrity to battery system 100. The second layer 62 is completely surrounded by the first layer 61 and the third layer 63 and consists of or comprises a phenolic micro balloon, for example a phenolic substance. It may include a silicone resin containing the microscopic spheres (heat resistant material). The second layer 62 may have a thickness of 5 mm to provide sufficient heat shielding against electric arcs that may be generated by one or more failed submodules 90 of the battery system 100.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Description of the sign

100 battery system

90 battery submodule

80 battery cells

10 electrode assembly

11 anode

12 cathode

13 separator

18, 19 first sidewall

16, 17 second side wall

21 positive terminal

22 negative terminal

27 Bottom

29 battery case sidewalls

30 cap assembly

31 cap plate

32 inlet

34 vent holes

38 sealing cap

39 Vent member

41, 42 current collector tab

43, 45 lower insulation

54 Upper insulation member

58 connecting plate

59 gasket

60 multilayer structure

61 first floor

62 second layer

63 3rd Floor

91 submodules

92 submodule shroud

93 submodule case

96 battery module case

97 sole plate

98 assembly area

99 cooling tubes

101 battery system case

102 battery system sidewall

103 Battery system base plate

Claims

As a wall structure of a case of one of a battery cell, a battery submodule, a battery module, and a battery system,

A multilayer structure having a first layer facing the inside of the case, a third layer facing the outside of the case, and a second layer disposed between the first layer and the third layer,

The first layer is configured to electrically insulate the second layer from the interior of the case,

The second layer comprises an ablative material and is configured to heat shield the third layer,

The third layer has a higher thermal conductivity than the second layer.
The method of claim 1,

The heat resistant material transitions to an ablation process at a temperature of 600 ° C. or less.
The method of claim 1,

The heat resistant material transitions to an ablation process in response to an electric arc impinging the first layer.
The method of claim 2 or 3,

The ablation process includes pyrolysis or carbonization of the material of the second layer.
The method of claim 1,

The second layer is completely enclosed between the first layer and the third layer.
The method of claim 1,

The heat resistant material is graphite, carbon-fiber-reinforced phenolic, epoxy resin, silicone elastomers, Teflon, quartz, cork. And one of nylons, or a composite thereof.
The method of claim 1,

And the third layer comprises a metal or a metal alloy.
The method of claim 7, wherein

The third layer is an alloy of aluminum, iron (Fe), carbon (C), chromium (Cr) and manganese (Mn), iron (Fe), carbon (C), chromium (Cr) and nickel (Ni). Wall structure, comprising at least one of the alloys.
The method of claim 1,

The third layer is configured to provide mechanical integrity to the case.
The method of claim 1,

And the first layer comprises a fiber reinforced plastic material.
The method of claim 1,

The material of the first layer has a melting point of at least 200 ° C.
A case of a battery cell for receiving an electrode assembly or a cap assembly for sealing an opening of the case comprises a wall structure according to claim 1,

The first layer is configured to electrically insulate the second layer from the electrode assembly.
The battery submodule case including a pair of submodule front plates accommodating a plurality of aligned battery cells and connected to the plurality of submodule side plates includes a wall structure according to claim 1,

Wherein the first layer is configured to electrically insulate the second layer from the plurality of battery cells.
A battery module case for accommodating at least one of a plurality of battery cells and a plurality of battery submodules and including a bottom plate comprises a wall structure according to claim 1,

And the first layer is configured to electrically insulate the second layer from at least one of the plurality of battery cells and the plurality of battery submodules.
A battery system case accommodating at least one of a plurality of battery cells, a plurality of battery submodules and at least one battery module includes a wall structure according to claim 1,

And the first layer is configured to electrically insulate the second layer from at least one of the plurality of battery cells, the plurality of battery submodules, and at least one battery module.