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DE-112017000254-B4 - battery

DE112017000254B4DE 112017000254 B4DE112017000254 B4DE 112017000254B4DE-112017000254-B4

Abstract

Battery (1), in particular a secondary battery, comprising a plurality of battery cells (5) arranged in a frame or housing (2), wherein at least two adjacent battery cells are thermally insulated by an intumescent protective material (6) from a predetermined temperature, wherein at least two battery cells (5) arranged in a row in at least one cell stack (3) in a stacking direction (4) are slidably arranged in the frame or housing (2) in the stacking direction (4), and wherein the protective material (6) is arranged at least between two battery cells (5) adjacent in the stacking direction (4) such that, from the predetermined temperature, the two adjacent battery cells (5) can be displaced from each other by the protective material (6) in the stacking direction (4) into a fire-resistant position, wherein the battery (1) comprises at least one separating means (9) for electrically isolating at least one electrical connection between two adjacent battery cells (5), characterized in that at least one separating means (9) is formed by a mechanical separating device (12), wherein the electrical separation is effected by the displacement of at least one battery cell (5) into The fire protection position is activated and at least one cell contact (7) of the battery cell (5) is severed.

Inventors

  • Andreas Koenekamp
  • Alexander Scheel
  • Manuela Leoni
  • Adrian Schmidt
  • Eduard Wagner
  • Martin Schwane
  • Andreas Musial

Assignees

  • AVL LIST GMBH

Dates

Publication Date
20260513
Application Date
20170220
Priority Date
20160219

Claims (11)

  1. Battery (1), in particular secondary battery, with a plurality of battery cells (5) arranged in a frame or housing (2), wherein at least two adjacent battery cells can be thermally insulated by an intumescent protective material (6) from a predetermined temperature are, at least two battery cells (5) arranged in a stack (3) in a stack direction (4) are slidably arranged in the frame or housing (2) in the stack direction (4) and the protective material (6) is arranged at least between two battery cells (5) adjacent in the stack direction (4) such that from the specified temperature the two adjacent battery cells (5) can be moved away from each other in the stack direction (4) by the protective material (6) into a fire protection position, wherein the battery (1) has at least one separating means (9) for electrical separation of at least one electrical connection between two adjacent battery cells (5), characterized in that at least one separating means (9) is formed by a mechanical separating device (12), wherein the electrical separation is effected by moving at least one battery cell (5) into the fire protection position and cutting through at least one cell contact (7) of the battery cell (5).
  2. Battery (1) after Claim 1 , characterized in that in the fire protection position the two adjacent battery cells (5) are thermally separated from each other.
  3. Battery (1) after Claim 1 , characterized in that the at least one electrical connection between two adjacent battery cells (5) has at least one predetermined breaking point (8) in the electrical connection between the two adjacent battery cells (5).
  4. Battery (1) after Claim 1 or 3 , characterized in that at least one separating agent (9) is formed by an aluminothermic mixture (10), wherein the electrical separation is effected by a thermite reaction at at least one electrical connection between two adjacent battery cells (5).
  5. Battery (1) according to one of the Claims 1 until 4 , characterized in that at least one separating agent (9) is formed by an electrically conductive solder or adhesive (11) between the cell contacts (7) of two adjacent battery cells (5), wherein the electrical separation takes place from a defined temperature and/or a defined tensile or shear stress between the cell contacts (7).
  6. Battery (1) according to one of the Claims 1 until 5 , characterized in that at least one separating agent (9) is formed by a bimetal (14) on at least the anode and/or the cathode of the cell contact (7), wherein the electrical separation is effected by a bending of the bimetal (14) from a defined temperature.
  7. Battery (1) after Claim 6 , characterized in that the mechanical separating device (12) is firmly connected to the frame or housing (2) of the battery (1).
  8. Battery (1) after Claim 6 or 7 , characterized in that the mechanical separating device (12) is formed by a cutting tool (13) having at least one cutting edge (13a), the cutting direction (S) of which is essentially parallel to the stacking direction (4).
  9. Battery (1) according to one of the Claims 1 until 8 , characterized in that at least one battery cell (5) is at least partially surrounded by a fire-resistant jacket comprising the intumescent protective material (6), wherein the fire-resistant jacket is preferably arranged as a fire-resistant layer, fire-resistant tape or fire-resistant mat on or at least one battery cell (5).
  10. Battery (1) according to one of the Claims 1 until 9 , characterized in that the battery cells (5) are formed by pouch cells.
  11. Method for deactivating a battery (1) comprising a plurality of battery cells (5) arranged in a frame or housing (2) according to one of the Claims 1 until 10 - in particular a secondary battery - in the event of damage, wherein at least two adjacent battery cells (5) are thermally insulated by intumescent protective material (6) from a predetermined temperature, wherein from a predetermined temperature two adjacent battery cells (5) are pushed away from each other into a fire protection position by the protective material (6) by increasing the volume of the protective material (6) in the stacking direction of the battery cells (5), characterized in that at least one electrical connection between two adjacent battery cells (5) is separated by a separating means (9) which is formed by a mechanical separating device (12).

Description

The invention relates to a battery, in particular a secondary battery, with a plurality of battery cells arranged in a frame or housing, wherein at least two adjacent battery cells can be thermally insulated by an intumescent protective material from a predetermined temperature. The invention further relates to a method for deactivating a battery comprising a plurality of battery cells arranged in a frame or housing in the event of damage, wherein at least two adjacent battery cells are thermally insulated by an intumescent protective material from a predetermined temperature. Rechargeable batteries with numerous battery cells are used, for example, to power motor vehicles. Since a voltage is present in the battery even when not in use, a fault can pose a danger to people and the environment, as energy, for example in the form of current, voltage, or heat, can be released uncontrollably. For example, if a local short circuit occurs in the internal cell contacts of a lithium-ion battery with liquid or electrolyte (lithium polymer battery), perhaps due to contamination of the separator by a trapped foreign particle or mechanical damage, the short-circuit current can heat the immediate vicinity of the fault to such an extent that surrounding areas are also affected. This can cause neighboring cells of a defective, so-called infected, battery cell to heat up to such a degree that thermal runaway occurs. This thermal runaway is an unstoppable chemical process that leads to the destruction of the infected cells. The energy stored in the battery is released within a short time. The infected battery cell can heat up to temperatures of 800°C. Through heat transfer, which typically occurs via the cell surfaces and the cell contacts (anode and cathode), the heat can then be transferred to neighboring cells and trigger thermal runaway in them as well. This creates a so-called "domino effect", which can lead to the destruction of all battery cells in the battery. Especially in lithium-ion batteries, this chain reaction is accelerated by the oxygen content of the air as soon as electrolyte escaping through the cell valve reacts with oxygen. Within the battery cell, dendrite formation leads to an internal short circuit, causing the boiling point to be exceeded. The molten substances are highly reactive and flammable. Therefore, an explosive thermal runaway can occur rapidly. From the US 7,781,097 B2 A device for preventing thermal runaway in a battery is known. It is proposed to apply a layer of intumescent material to the outer surfaces of the cells. In the event of thermal runaway, the intumescent material expands above a certain activation temperature and is displaced into existing gaps between the cells, thereby forming an insulating layer. Furthermore, it is from the US 2015/0325826 A1 A similar battery for a hand-held power tool is known, wherein at least one battery cell is designed as an insulating battery cell and is provided with a fire-resistant jacket comprising an intumescent material. Furthermore, the documents show DE 10 2015 007 408 A1 and DE 20 2013 001662 U1 The use of intumescent material to separate an electrical contact between two contacts in the event of temperature-induced damage is known. Both in the US 7,781,097 B2 , as well as in the US 2015/0325826 A1 and the DE 20 2013 001662 U1 At a given temperature, the intumescent material is displaced into existing cavities between the battery cells due to volume expansion resulting from foam formation. Also known is the EP 2 618 397 A1 , which reveals a separating agent made of bimetallic material, wherein at a certain temperature the bimetallic material separates the cell contacts of the anode and the cathode. Furthermore, the WO 2012/065694 A1 known which exothermic solder foils are revealed on individual electrical conductors, which cause the respective conductors to melt when a temperature is exceeded. Current battery systems are often built from pouch cells due to their improved efficiency. These are typically arranged directly next to each other and usually separated only by a thin insulating film, thus maximizing the energy output from the US 7,781,097 B2 or the US 2015/0325826 A1 The known concept is not directly applicable. Batteries with plate-shaped cells or pouch cells typically do not have a cavity in front. hands in which the intumescent protective material could spread by forming foam. Furthermore, the cell contacts are made of materials with high thermal conductivity. Therefore, in the event of thermal runaway of the battery, a significant amount of heat can flow from the infected cell to the neighboring cell via the cell contacts, thus perpetuating the thermal chain reaction. The object of the invention is to avoid these disadvantages and to prevent infection of neighboring battery cells in the event of thermal runaway of a defective battery cell. According to the invention, this is achieved by arranging at least two battery cells in at