Battery and method for its operation

Abstract

A battery (10), in particular a high-voltage battery, comprising a casing (12) enclosing at least one battery cell (11), wherein a sensor (14) is arranged via a contact surface (15) on an outer side (13) of the casing (12) facing away from the battery cell (11), and the outer side (13) is covered, at least in the region of the contact surface (15), with a thermoelectric converter (16) which is configured to convert heat emitted by the battery cell (11) during its operation into electrical energy and to feed it into the sensor (14) in order to supply the latter with electrical energy for its intended operation; furthermore, a method for operating a battery (10).

Description

The invention relates to a battery, for example a high-voltage battery, having at least one battery cell and to a method for operating such a battery.For reliable and safe operation of batteries, for example high-voltage batteries as traction batteries in electric vehicles or storage batteries for photovoltaic systems, these are usually monitored during operation by means of sensors in order to ascertain, for example, a state of charge (SOC="State of Charge"), a state of health (SOH="State of Health"), temperature and the like. A battery monitoring or battery management system (BMS) can take suitable countermeasures, for example interrupt a charging or discharging process, when it is determined that respective limit values of the monitored battery variables are not permitted to be exceeded, in order to ensure safe battery operation at any time. In addition to safe operation, the battery management system (BMS) can additionally maximize a battery life by dynamically adapting discharge and / or charge strategies depending on the monitored battery sizes.Sensors are used to detect the battery sizes. These usually require an external power supply (e.g. 12 V) for their intended operation. The power supply requires electrical cabling external to the sensor, which usually has to be carried out manually. In addition to the costs for the supply cables or lines, manual installation involves a considerable expenditure in time, which slows down and makes the production of the batteries more expensive. In addition, the supply lines represent an additional potential source of error. For example, insulation of the cables may be damaged due to improper routing (e.g., pinching or squeezing between battery housing portions, scrubbing at housing edges, and the like) and may result in a battery failure.EP 4 401 299 A1 discloses a secondary battery having a power generation function which is formed by a thermoelectric element for generating energy from heat.US 2022 / 0 320 876 A1 describes a multistage battery system for data centers, which converts thermal energy from waste heat of a first battery into electrical energy with the aid of a thermoelectric element. This recovered energy is used to charge a second (or more additional) battery(s) that may function as a backup or to support load spikes.WO 2015 / 050 112 A1 discloses a flexible organic thermoelectric conversion element which can convert heat into electrical energy. The element is based on a layer of an organic thermoelectric material consisting of carbon nanotubes (CNTs), a polymer and a special adhesion promoter (compound C) in order to achieve a high adhesion strength of an active layer on flexible substrates or metal electrodes.Against this background, the object of the invention is to provide a battery and a method for the operation thereof which overcomes the aforementioned disadvantages, ensures reliable and safe operation with high efficiency and reduces the production and implementation outlay.This object is achieved by a battery having the features of claim 1 and by a method for operating a battery having the features of claim 7. Further, particularly advantageous embodiments of the invention are disclosed in the respective dependent claims.It should be noted that the features listed individually in the claims can be combined with one another in any technically expedient manner (even beyond category limits, for example between method and apparatus) and reveal further configurations of the invention. The description additionally characterizes and specifies the invention, in particular in conjunction with the figures.It should be further noted that a conjunction "and / or" used herein, between two features and linking them to one another, should always be interpreted such that in a first configuration of the subject matter according to the invention only the first feature may be present, in a second configuration only the second feature may be present, and in a third configuration both the first and the second feature may be present.The invention relates to a battery, for example a high-voltage battery, which has at least one battery cell which is surrounded by a casing. On an outer side of the casing facing away from the battery cell, a sensor is arranged via a contact surface. Furthermore, the outer side is covered with a thermoelectric converter at least in the region of the contact surface. The thermoelectric converter is configured to convert heat (i.e. waste heat) emitted by the battery cell during its operation into electrical energy and feed it into the sensor in order to supply it with electrical energy for its intended operation.The battery can be, for example, a traction battery for the electric drive of an electrically operated vehicle or a storage battery for storing regenerative energies, which are obtained from energy sources such as bioenergy (biomass potential), geothermal energy, water power, marine energy, solar energy and wind energy. In particular, the battery is a rechargeable battery. Operation of the battery may include both output of energy from the battery to an electrical load and injection of energy into the battery from an electrical energy source (e.g., generator). The battery can have a single battery cell or a combination of a plurality of battery cells (e.g. battery pack or rechargeable battery pack).The sensor, e.g. detector, measurement variable or measuring pickup or sensor, is a technical component which can record specific physical or chemical properties (physically e.g. heat quantity, temperature, humidity, pressure, sound field variables, brightness, acceleration or chemically e.g. pH value, ionic strength, electrochemical potential) and / or the material nature of its environment qualitatively or quantitatively as a measurement variable. These quantities are detected by means of physical, chemical or biological effects and transformed into an electrical signal that can be processed further and output.The thermoelectric converter (also referred to as a thermoelectric generator) is a technical component that converts a temperature gradient into electrical energy. The thermoelectric conversion is based on the thermoelectric effect, also called the Seebeck effect. Metals are known as materials (e.g. in thermocouples). Instead of metals, semiconductor materials similar to the Peltier element can be used, whereby the efficiency with respect to metallic thermocouples can be increased. The thermoelectric converter is inserted between the contact surface of the sensor and the outer side of the shell and may be fixed to the outer side of the shell and / or to the contact surface of the sensor.By utilizing the waste heat produced by the battery during its operation for the operational electrical supply of the sensor, the efficiency of the battery-sensor system is increased. In addition, separate supply lines which are routed from the outside to the sensor can be dispensed with, since the sensor is arranged in the immediate vicinity of the thermoelectric converter and the electrical energy supply connection from the thermoelectric converter to the sensor can be effected directly and on the shortest path, i.e. substantially without a cable which is external to the sensor and extends beyond the contact surface of the sensor. Power supply terminals of the sensor may be directly electrically connected to output terminals of the thermoelectric converter. This simplifies the production of the battery sensor system, since no separate supply lines have to be laid-in particular manually. Machine production is thus made possible. In addition, the costs for the saved supply lines are dispensed with. In addition, the invention eliminates a potential source of error, e.g. clamping or squeezing PPE cables in the event of incorrect installation on a battery housing.In addition, additional cooling of the battery is achieved via the contact surface of the sensor or via the thermoelectric converter as a result of the electrical supply of the sensor.The thermoelectric converter can be designed as a coating comprising a material mixture of silicon, tungsten, aluminum and vanadium. As a result, a high ZT value of the thermoelectric converter, in particular preferably greater than five or greater than six, is achieved. The ZT value represents a quantitative measure of the efficiency of the thermoelectric converter. A ZT value greater than zero means that the material of the thermoelectric converter generates energy from heat. The thermoelectric converter according to this embodiment further increases the efficiency of the battery sensor system.In further embodiments, the sensor is fastened to the casing exclusively via the contact surface, which simplifies the assembly of the sensor, in particular when fastening the sensor by means of an adhesive, which can particularly preferably be a thermally conductive adhesive. A variable to be detected by the sensor, such as a temperature, can be detected directly at the contact surface, but is not necessarily limited thereto. The sensor can be configured to detect physical or chemical variables of its environment independently of the contact surface.Other preferred embodiments provide that the sensor is fastened to the sheath by means of a thermally conductive adhesive, screwing or laser welding in order to ensure reliable fastening of the sensor. In addition, a contact of the contact surface of the sensor with the outer side of the casing is formed, which allows a reliable and accurate detection of, for example, a temperature directly at the contact surface by the sensor.In still further embodiments, the shell is a solid housing enclosing the at least one battery cell. A hard, stable and compact structure of the housing is able to ensure effective protection of the battery cell against external mechanical stress or damage. On the other hand, such a housing is able to protect the environment of the battery from damaging (e.g. thermal and / or chemical) influences of the battery, for example in the event of a fault.The housing preferably has a good thermal conductivity in order to efficiently discharge the generated waste heat of the battery cell to the outside. The housing may be formed of a metal material (e.g., aluminum), for example. Preferably, a plurality of battery cells are accommodated in the housing.According to another advantageous embodiment, at least one cooling element is provided on the outer side of the casing, on which cooling element the contact surface of the sensor is arranged. The cooling element can be designed, for example, as a cooling fin. In order to efficiently fulfil its function as a cooling element, the waste heat generated by the battery cell can be concentrated towards the cooling element, so that a large temperature gradient is established between the cooling element and its environment and the thermoelectric converter arranged on the contact surface can be operated particularly efficiently and generate and provide a larger amount of electrical energy.Further preferred embodiments provide that the sensor is designed to detect a physical or chemical property of the battery cell, such as temperature, state of charge, capacitance, voltage, current and the like, and to convert and output it into an electrical signal. Depending on the variable to be detected (e.g. temperature), this can be detected directly at the contact surface.The invention further relates to a method for operating a battery, for example a high-voltage battery, which has a casing enclosing at least one battery cell, wherein a sensor is arranged on an outer side of the casing facing away from the battery cell via a contact surface and the outer side is covered with a thermoelectric converter at least in the region of the contact surface. The method provides that heat (i.e. waste heat) emitted by the battery cell during its operation is converted into electrical energy by means of the thermoelectric converter and this energy is fed into the sensor in order to supply it with electrical energy for its intended operation.It is to be understood that definitions of terms relating to the claimed method and with respect to the effects and advantages of features of the claimed method can be used to fully utilize the disclosure of analogous definitions, effects and advantages of the battery and vice versa. Repetition of explanations of correspondingly identical features, the effects and advantages thereof can thus be dispensed with in favor of a more compact description, without such omissions having to be interpreted as a restriction for one of the disclosed subject matter of the invention.In a particularly preferred embodiment, the battery is cooled by means of the intended operation of the sensor in that the thermoelectric converter converts the waste heat generated by the battery into electrical energy and feeds it into the sensor for its operation. A specific number of the sensors provided, a specific placement of the sensor or sensors on the outer side of the casing of the battery cell and / or a specific size of the contact surface(s) can be designed in accordance with the desired cooling power.Further features and advantages of the invention will become apparent from the following description of an exemplary embodiment of the invention, which is to be understood as non-limiting and is explained in more detail below with reference to the drawings.The single FIG. 1 schematically illustrates a partial view of a battery 10 according to an embodiment of the invention.In FIG. 1, a part of a battery cell 11 of the battery 10 is shown. It is understood that the battery 10 (e.g., high voltage battery) may include more than one battery cell 11. In any case, the at least one battery cell 11 is surrounded by a casing 12 (e.g. housing). It can be seen in FIG. 1 that a sensor 14 is arranged on an outer side 13 of the casing 12 facing away from the battery cell 11 via a contact surface 15.The sensor 14 is configured, for example, to record a physical or chemical property and / or the material nature of its environment qualitatively or quantitatively as a measurement variable. These detected variables are transformed into an electrical signal by sensor 14 and are output by the latter. The variable detected by the sensor 14 may be a property of the battery cell 11 and / or the battery 10 (e.g. temperature, electrical voltage, current, state of charge, etc.). The variable detected by the sensor 14 can alternatively or additionally be a property of its environment.It can further be seen from FIG. 1 that the outer side 13 is covered (e.g. coated) with a thermoelectric converter 16 at least in the region of the contact surface 15, which converter is configured to convert heat or waste heat emitted by the at least one battery cell 11 during its operation into electrical energy and feed it into the sensor 14 in order to supply it with electrical energy for its intended operation. The electrical energy can be fed from the thermoelectric converter 16 into the sensor 14 directly via electrical connections not shown in FIG. 1, so that no wiring external to the sensor and / or converter by means of separate power supply lines, which would extend away from the sensor 14 and the thermoelectric converter 16, is required.The thermoelectric converter 16 may be formed as a coating of a material mixture of silicon, tungsten, aluminum and vanadium, but is not necessarily limited thereto. However, such a coating represents a preferred embodiment which enables a high ZT value of preferably at least five or greater and thus a high efficiency of the thermoelectric converter 16.As can be further seen in FIG. 1, the contact surface 15 or the surface of the thermoelectric converter 16 can be larger than would be necessary solely for enclosing the sensor 14 in a sensor housing. On the one hand, a larger amount of energy can be obtained from the waste heat of the battery 10 by means of a larger contact or converter surface. On the other hand, the larger area can also contribute to a higher cooling capacity and thus improved cooling of the battery 10. In particular with regard to the cooling of the battery 10 effected by the thermoelectric converter 16 and the energy consumption by the sensor 14, a plurality of sensors, which do not necessarily have to record the same physical or chemical variable, can be arranged on the outer side 13 of the casing 12.The sensor 14 can be fastened to the sheath 12 exclusively via the contact surface 15.Basically, the sensor 14 may be attached to the shell 12 by a thermally conductive adhesive, bolting, or laser welding.The casing 12 can be designed as a solid housing enclosing the at least one battery cell 11 and can be formed, for example, from a metal material or plastic.The shell 12 may have a cooling element (e.g. cooling fin) (not shown) on which the contact surface 15 of the sensor 14 is arranged.LIST OF REFERENCE CHARACTERS:10 Battery 11 Battery cell 12 Casing 13 Outer side 14 Sensor 15 Contact surface 16 Thermoelectric converter

Claims

Battery (10), in particular a high-voltage battery, having a casing (12) enclosing at least one battery cell (11), wherein a sensor (14) is arranged on an outer side (13) of the casing (12) facing away from the battery cell (11) via a contact surface (15), and the outer side (13) is covered, at least in the region of the contact surface (15), with a thermoelectric converter (16) which is configured to convert heat emitted by the battery cell (11) during its operation into electrical energy and to feed it into the sensor (14) in order to supply it with electrical energy for its intended operation.Battery according to claim 1, wherein the sensor (14) is fastened to the shell (12) exclusively via the contact surface (15).The battery of any preceding claim, wherein the sensor (14) is attached to the shell (12) by a thermally conductive adhesive, bolting or laser welding.Battery according to one of the preceding claims, in which the casing (12) is a fixed housing enclosing the at least one battery cell (11).Battery according to one of the preceding claims, in which at least one cooling element is provided on the outer side (13) of the casing (12), on which cooling element the contact surface (15) of the sensor (14) is arranged.Battery according to one of the preceding claims, in which the sensor (14) is designed to sense a physical or chemical property of the battery cell (11) and to convert it into an electrical signal and output it.Method for operating a battery (10), in particular a high-voltage battery, which has a casing (12) enclosing at least one battery cell (11), wherein a sensor (14) is arranged on an outer side (13) of the casing (12) facing away from the battery cell (11) via a contact surface (15) and the outer side (13) is covered with a thermoelectric converter (16) at least in the region of the contact surface (15), wherein, in the method, heat emitted by the battery cell (11) during its operation is converted into electrical energy by means of the thermoelectric converter (16) and this energy is fed into the sensor (14) in order to supply it with electrical energy for its intended operation.Method according to claim 7, wherein the battery (10) is cooled by means of the intended operation of the sensor (14).

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