energy storage system

Abstract

An energy storage system (1) comprising a housing (2) in which a plurality of energy storage units (3) are arranged, wherein between the energy storage units (3) frame elements (5) are arranged which separate the energy storage units (3), wherein a circumferential edge (6) of the frame elements (5) is equipped with a sealing body (7), wherein the sealing body (7) at least partially forms a non-return valve.

Description

Technical Field

[0001] The present invention relates to an energy storage system comprising a housing in which a plurality of energy storage units are arranged, wherein a frame element is arranged between the energy storage units to separate them, and wherein a sealing body is provided around the periphery of the frame element. Background Technology

[0002] Such an energy storage system is disclosed in EP 2 273 162 A1. Energy storage systems incorporating energy storage units have wide applications, particularly as rechargeable energy storage devices in mobile and stationary systems. In this case, the energy storage system, in the form of a rechargeable storage device, is used in portable electronic devices, such as measuring instruments, medical devices, tools, and consumer products. Furthermore, the energy storage system, in the form of a rechargeable storage device, is also used to provide power to electric vehicles. In this case, the electric vehicle can be a two-wheeled vehicle, a four-wheeled vehicle, such as a passenger car, or a commercial vehicle (such as a bus, truck, rail vehicle, or forklift). Additionally, the energy storage system is also used in ships and aircraft.

[0003] It is also known that energy storage systems in the form of rechargeable storage devices are used in stationary applications, such as as backup systems in network infrastructure and for storing electrical energy from renewable energy sources.

[0004] One common type of energy storage system is a rechargeable storage device in the form of a lithium-ion battery. Like other rechargeable storage devices, this type of system typically has multiple energy storage units arranged within a housing. In this case, multiple energy storage units arranged in the housing and electrically connected to each other form a module.

[0005] Other known energy storage systems include lithium-sulfur batteries, solid-state batteries, or metal-air batteries.

[0006] The aforementioned rechargeable energy storage device has a maximum capacity only within a limited temperature range. If the temperature exceeds or falls below this range, the energy storage device's capacity will drop sharply, and at the very least, its functionality will be affected.

[0007] In particular, excessively high temperatures can damage energy storage devices. In this regard, especially in the case of lithium-ion batteries, the so-called "thermal runaway" is well-known. This occurs when a large amount of heat and gaseous degradation products are released in a short period, causing high pressure and high temperature within the energy storage unit. This effect is particularly problematic for systems with high energy density and multiple energy storage units in a confined space. This is, for example, the case with energy storage systems used to power electric vehicles.

[0008] In the event of thermal runaway in an energy storage unit, the temperature can reach 600°C or higher within seconds. In this situation, appropriate measures should be taken to reduce the energy transferred to adjacent energy storage units to a level that prevents their temperatures from becoming excessively high. Preferably, the temperature of adjacent energy storage units should not exceed 100°C. However, this value largely depends on the chemicals used in the energy storage units. In this case, irreversible damage to the affected energy storage unit cannot be prevented, but thermal propagation to adjacent energy storage units can be prevented.

[0009] Besides thermal runaway, venting is another form of damage to energy storage units. For example, in the case of a pouch cell energy storage unit, gases generated within the unit are released from the thin-film casing through openings. This venting is particularly likely to occur during thermal runaway. When venting occurs, no temperature rise is typically observed, or only a moderate one. In this case, the released gases are usually degradation products of materials present inside the energy storage unit (such as electrolytes or binders). These released gases are highly reactive and can damage adjacent energy storage units. In this respect, such events are critical to the safety of the energy storage system. Summary of the Invention

[0010] The purpose of this invention is to provide an energy storage system with improved operational safety.

[0011] The solution of the present invention to achieve the above-mentioned objective is characterized by the features of claim 1. Advantageous technical solutions are described in the dependent claims.

[0012] The energy storage system according to the present invention includes a housing in which a plurality of energy storage units are arranged, wherein a frame element is arranged between the energy storage units, the frame element separating the energy storage units, and wherein a sealing body is provided along the circumferential edge of the frame element, wherein the sealing body at least partially forms a check valve.

[0013] Accordingly, in the energy storage system according to the invention, the energy storage units are separated and isolated from each other by frame elements. In this case, depending on the specific technical solution of the energy storage unit, the frame element may be plate-shaped. In this case, the frame element covers the main side of the energy storage unit. A sealing body is arranged in the edge region, wherein the sealing body is fixed to the frame element. The energy storage unit is individually encapsulated by the frame element and the sealing body fixed to the frame element. Since a check valve is at least partially formed in the sealing body, pressure balance can be achieved in the event of a fault. If a fault causes the discharge of gaseous products from a single energy storage unit, an overpressure will occur in the space between the frame element and the circumferential sealing body, which can be eliminated by the check valve. The check valve may communicate with a space or channel for discharging degradation products. In this case, only the check valve corresponding to the damaged energy storage unit will open. Check valves belonging to adjacent energy storage units remain closed, preventing harmful products escaping from the damaged energy storage unit from contacting other energy storage units. This prevents the fault from spreading to adjacent energy storage units.

[0014] The energy storage units can be arranged between the frame elements, with sealing lips formed by the sealing bodies, and the sealing lips of adjacent frame elements facing each other. In this technical solution, the sealing lips are linearly abutting each other, and the contacting sections of the sealing lips can form check valves. Thus, harmful gases can escape from any location in the edge region of the energy storage unit.

[0015] The sealing lip can be sealed using elastic prestress. This ensures that unwanted external materials cannot penetrate the space between the frame element and the sealing body, in which the energy storage unit is arranged.

[0016] The sealing lip can arch away from the energy storage unit. In this technical solution, the sealing lip protrudes outward. Furthermore, if the sealing lips are pressed together by prestress, they form an opening in the form of a check valve. If the internal pressure (i.e., the space where the energy storage unit is located) increases, the sealing lips will be squeezed outward, eventually separating and releasing the passage. Conversely, increased pressure on the outer side will cause the sealing lips to press more firmly together, thereby blocking the passage.

[0017] The sealing body can be made of an elastic material. For this purpose, the sealing body can be made of, for example, an elastomeric sealing material, such as silicone rubber. In this technical solution, the sealing lip of the sealing body itself is elastically movable, thereby enabling the sealing lip to form a particularly effective anti-return function.

[0018] The sealing body can be made of a shape-stable material. For this purpose, the sealing body can be formed of a strip of material in the form of a sealing lip, wherein the strip of material forms a sealing lip that arches outward after installation. In this technical solution, the sealing lip functions as a valve and also allows harmful gases to escape from the inside to the outside. Therefore, the sealing body is preferably pivotally fixed to a frame element.

[0019] The energy storage unit can be constructed as a pouch cell with a circumferential seal. In the case of a pouch cell, the active material is arranged in a thin film, which forms the circumferential seal. This is especially true when using a two-piece thin film with the active material arranged between it.

[0020] The sealing lip can be abutted against the sealing seam by means of elastic prestress. In this technical solution, the sealing body is used not only as a sealing element but also as a retaining element. The energy storage unit is fixed between the frame elements by the sealing seam sandwiched between the sealing lips. This eliminates the need for additional retaining elements. In this technical solution, the sealing of the internal space is achieved between the sealing lips and the sealing seam. Therefore, the sealing lips of the sealing body abut against the circumferential sealing seam of the energy storage unit from both sides.

[0021] The seal can be held in a form-fitting manner on the frame element. This simplifies the installation and manufacturability of the energy storage system. Attached Figure Description

[0022] The following will describe in detail several technical solutions of the energy storage system according to the present invention with reference to the accompanying drawings. The accompanying drawings schematically illustrate: Figure 1 This is a cross-sectional view of an energy storage system with a valve-shaped seal. Figure 2 This is a cross-sectional view of an energy storage system with an elastic seal. Detailed Implementation

[0023] These figures illustrate an energy storage system 1, which includes a housing 2 in which multiple energy storage units 3 are arranged. Each energy storage unit 3 has a thin-film housing composed of a first thin film and a second thin film, wherein the first and second thin films are connected to each other by material bonding along their circumferential edges through a sealing seam 4. The thin-film housing houses an electrode-separator assembly, wherein the electrodes protrude from the thin-film housing in the region of the sealing seam 4. Conductive contact between the electrode-separator assembly and the electrodes is possible. The first and second thin films are made of aluminum and have an inner coating based on a non-conductive polyolefin tackifier and an outer coating based on a polyamide plastic. The energy storage unit 3 is configured as a lithium-ion battery.

[0024] The energy storage units 3 are separated from each other by the frame element 5. The energy storage units 3 and the frame element 5 form a sandwich structure. A sealing body 7 is provided along the circumferential edge 6 of the frame element 5. The sealing body 7 at least partially forms a check valve.

[0025] The energy storage units 3 are respectively arranged between two frame elements 5, wherein a sealing lip 8 is formed by a sealing body 7, and the sealing lips 8 of adjacent frame elements 5 face each other. In this case, the sealing lips 8 are arched in a direction away from the energy storage unit 3. In this case, the sealing lips 8 communicate with a region of the housing 2, which forms a discharge region.

[0026] The sealing lip 8 is prestressed and abuts against the sealing seam 4 of the energy storage unit 3. If harmful gases are released from the energy storage unit 3 in the event of damage, an overpressure will be generated in the space between the frame element 5 and the sealing body 7. This overpressure will cause the sealing lip 8 to be separated from the sealing seam 4 by a certain distance, thereby allowing the harmful gases to enter the discharge area. Conversely, for the remaining undamaged energy storage units 3, the sealing body 7 is sealed against the sealing seam 4, preventing harmful gases escaping from the damaged energy storage unit 3 from coming into contact with other energy storage units 3.

[0027] Figure 1 This diagram illustrates a technical solution where the sealing body 7 is made of a shape-stable material. The sealing body 7 is strip-shaped, wherein the strip-shaped element forms a sealing lip 8. The sealing body 7 is pivotally arranged on the frame element 5.

[0028] Figure 2 This invention illustrates a technical solution where the sealing body 7 is made of an elastic material. In this solution, the sealing body 7 is composed of an elastomeric material and is made of silicone rubber. The sealing body 7 is shape-fitted onto the frame element 5. Through the elasticity of the sealing body 7, the sealing lip 8 is abutted against the sealing seam 4 of the energy storage unit 3 by means of elastic prestress.

Claims

1. An energy storage system (1), the energy storage system comprising a housing (2), wherein a plurality of energy storage units (3) are arranged in the housing, wherein, A frame element (5) is arranged between the energy storage units (3), the frame element (5) separating the energy storage units (3), and a sealing body (7) is provided on the periphery (6) of the frame element (5), characterized in that the sealing body (7) at least partially forms a check valve.

2. The energy storage system according to claim 1, characterized in that, The energy storage units (3) are arranged between the frame elements (5), wherein the sealing lip (8) is formed by the sealing body (7), and the sealing lips (8) of adjacent frame elements (5) face each other.

3. The energy storage system according to claim 2, characterized in that, The sealing lip (8) is sealed by means of elastic prestress.

4. The energy storage system according to claim 2 or 3, characterized in that, The sealing lip (8) arches in a direction away from the energy storage unit (3).

5. The energy storage system according to any one of claims 1 to 4, characterized in that, The sealing body (7) is made of an elastic material.

6. The energy storage system according to any one of claims 1 to 4, characterized in that, The sealing body (7) is made of a shape-stable material.

7. The energy storage system according to any one of claims 1 to 6, characterized in that, The sealing body (7) is pivotally fixed to the frame element (5).

8. The energy storage system according to any one of claims 1 to 7, characterized in that, The energy storage unit (3) is constructed as a pouch battery and has a circumferential sealing seam (4).

9. The energy storage system according to claim 8, characterized in that, The sealing lip (8) is attached to the sealing seam (4) by means of elastic prestress.

10. The energy storage system according to any one of claims 1 to 9, characterized in that, The sealing body (7) is shaped to fit on the frame element (5).

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