SAFETY DEVICE, BATTERY PACK WITH A SAFETY DEVICE AND METHOD FOR MANUFACTURING A SAFETY DEVICE

Description

State of the art

[0001] A safety device for at least one battery cell has already been proposed, comprising a safety element for interrupting a current flow from the battery cell in a critical state of the battery cell, a heating unit coupled to the safety element, in particular electrically and / or thermally and / or mechanically, and provided to assist in triggering the safety element, and a control unit for activating the heating unit in the critical state. Document US 2007 / 188148 discloses a unit according to the preamble of claim 1. Disclosure of the invention

[0002] The invention is based on a safety device according to claim 1.

[0003] It is proposed that the securing device has at least one carrier element for receiving the securing element and at least one heating element of the heating unit.

[0004] The inventive design of the safety device advantageously increases safety. It can advantageously promote triggering of the protective element in the critical state of the battery cell or even enable triggering in certain critical states. Furthermore, the problem of unprotected areas, which previously existed with known safety devices from the prior art, can be advantageously solved. This problem, for example, could arise at certain charge levels in combination with certain short-circuit resistances, which can arise due to different triggering characteristics of different safety elements, for example, between the triggering characteristic of a fuse and the triggering characteristic of a CID ("Current Interruption Device") in conventional lithium-ion battery packs. Furthermore, efficiency can advantageously be improved.In particular, the use of expensive non-standard components can be avoided, thus improving cost efficiency. Furthermore, the design of existing protective elements can be simplified, thus improving efficiency in development and / or manufacturing.

[0005] The safety device has the safety element for interrupting a current flow in a critical state of the battery cell and can also have further safety elements. The battery cell can be part of a battery pack and in particular can be operated in combination with other battery cells of the battery pack, which can be electrically connected in parallel and / or electrically in series with the battery cell. The safety device is then advantageously also part of the battery pack. It is conceivable that the safety device is provided for several battery cells of the battery pack. The battery pack can also have several safety devices, in particular one safety device for each battery cell. Alternatively, the battery cell can also be operated individually and connected to the safety device for protection. The safety device is not limited to the use of a specific type of battery cell and / or battery pack.The safety device can, for example, be intended for use with battery cells of lithium-ion batteries and / or lithium polymer batteries and / or nickel-cadmium batteries and / or other known battery types that appear appropriate to a person skilled in the art, without being limited thereto. The safety device is also not limited to a specific geometry and / or format of battery cells and / or battery packs. The battery cell can, for example, have various cell geometries and / or cell formats and be designed, for example, as a round cell, a flat cell, a pouch cell, or the like.

[0006] The fuse element can, without being limited thereto, be designed, for example, as a fuse and / or as a sheet metal strip fuse and / or as a temperature-variable resistor, for example as a PTC (positive temperature coefficient thermistor), and / or as a copper track, in particular a narrowed one, on a circuit board. It is also conceivable for the fuse element to be designed as a solder bridge or as a metal alloy, e.g. as a tin alloy, which has a defined cross-section and a defined length and therefore a defined resistance and thus a defined melting characteristic. In addition, the fuse element can be designed as a bi-metal component, which has a defined bending characteristic when exposed to temperature changes and bends under thermal influence in such a way that a current flow from the battery cell is interrupted.

[0007] A critical condition of the battery cell may, for example, be, but is not limited to, an increased current and / or voltage compared to a normal condition, in particular a short circuit of the battery cell, and / or overheating of the battery cell and / or an area surrounding the battery cell and / or overpressure in the battery cell and / or the like.

[0008] The heating unit is provided to assist in triggering the fuse element and for this purpose has at least one heating element. The heating unit can have a plurality of heating elements. The heating unit is provided to additionally apply thermal and / or electrical stress to the fuse element in a critical state of the battery cell and thus promote triggering of the fuse element and thus an interruption of the current flow from the battery cell. The heating element of the heating unit can, for example, have a corresponding structure for thermally and / or electrically stressing the fuse element in the critical state of the battery cell and can comprise one or more materials with corresponding electrical and / or thermal properties, for example made of copper and / or aluminum and / or silver and / or the like, and / or be formed from such materials.For example, the heating element can be designed as a wire or as a spiral and / or meandering copper structure. If the carrier element is designed as a printed circuit board, the heating element can also be designed as a copper track of any shape, for example a straight or zigzag copper track or the like. Alternatively or additionally, the heating element can also be designed as a heatable component, for example as a resistor, in particular a temperature-variable resistor, and / or as a semiconductor component and / or the like. Preferably, a heating power of the heating unit is determined by a resistor design in conjunction with an available voltage of the battery cell and / or the battery pack containing the battery cell.

[0009] The heating element of the heating unit is coupled to the fuse element, in particular electrically and / or thermally and / or mechanically. For example, the heating element can be coupled to the fuse element by direct contact, for example via a soldered connection and / or plug connection and / or welded connection and / or via direct mechanical contact. Alternatively or additionally, the heating element can be thermally coupled to the fuse element via one or more components with good thermal conductivity and / or by means of thermally conductive paste and / or the like.

[0010] To supply energy, the heating element is preferably electrically connected to at least one electrical terminal of the battery cell, at least in the critical state of the battery cell. The heating element can be connected to the at least one electrical terminal of the battery cell via common connection types, for example via a soldered connection and / or a welded connection and / or via a press-in pin and / or a screw contact and / or via corresponding copper tracks and / or the like. Alternatively, however, it would also be conceivable for the safety device to have a separate energy supply, for example a separate rechargeable battery and / or a separate battery, to supply the heating unit and for the heating element to be connected to the energy supply via corresponding connection types.

[0011] The control unit is provided for activating the heating unit and, for this purpose, preferably has at least one switching element which is provided for establishing an electrically conductive connection between the heating element of the heating unit and an electrical connection of the battery cell in a critical state of the battery cell in order to activate the heating unit. The switching element can be designed, for example, as a relay. Preferably, the switching element is designed as a semiconductor switching element, for example as a transistor or the like. The control unit can be provided for controlling the switching element by means of a modulation technique, for example by means of pulse width modulation, in order to control and / or regulate a heating output of the heating unit.It is conceivable that the control unit has a measuring unit for measuring at least one parameter of the heating unit, for example, an electric current and / or an electric voltage and / or a temperature of the heating unit. The control unit can be provided to regulate the heating unit based on the parameter detected by the measuring unit. Preferably, the control unit is provided to control the heating unit for a limited period of time, for example, for 30 seconds, in particular to limit the energy input of the heating unit to the safety element and / or other components of the safety device and / or the battery pack.

[0012] The support element of the securing device is provided for accommodating the securing element and the at least one heating element of the heating unit and has a corresponding structure for this purpose. It is also conceivable that the securing element and / or the heating element is / are formed integrally with the support element. "Integral" is to be understood in particular as being at least materially connected, for example, by a welding process, an adhesive process, an injection molding process, and / or another process deemed appropriate by a person skilled in the art, and / or advantageously formed in one piece, such as by being manufactured from a single casting and advantageously from a single blank.

[0013] In this document, numerals such as "first" and "second," which precede certain terms, serve only to distinguish between objects and / or to correlate objects with each other and do not imply a total number and / or ranking of the objects. In particular, a "second object" does not necessarily imply the presence of a "first object."

[0014] "Intended" should be understood as specifically configured, specifically designed, and / or specially equipped. The fact that an object is intended for a specific function should be understood as meaning that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0015] It is further proposed that the carrier element be designed as a printed circuit board. This advantageously enables adaptation of the security device to different requirements using particularly simple technical means. The printed circuit board can be designed as a rigid printed circuit board (rigid PCB) or as a flexible printed circuit board (flex PCB). Preferably, the security element is applied to the printed circuit board as a copper structure, in particular as a narrowed copper track. The heating element can also be applied to the printed circuit board as a copper structure of any desired shape, for example as a straight or zigzag-shaped, advantageously as a spiral and / or meander-shaped copper structure.It is also conceivable for the heating element to be designed as an electrical and / or electronic component, for example as a resistor, in particular a temperature-variable resistor, and / or as a semiconductor component and / or the like, and for the circuit board to be equipped with such a component. The fuse element and the heating element can be arranged on different sides of the circuit board or on the same side of the circuit board. The circuit board can be single-layer or multi-layer.

[0016] In an alternative advantageous embodiment, it is proposed that the fuse element be formed integrally with the carrier element. This advantageously enables particularly simple and efficient manufacture of the fuse device. For example, the fuse element can be designed as a metal strip fuse, and the heating element can be arranged on and / or around the fuse element, for example as an insulated wire. It is also conceivable for the heating element to be formed from branched-off parts of the fuse element designed as a metal strip fuse and to be arranged on and / or around the fuse element, wherein the heating element is electrically insulated from heated regions of the protective element, for example by an insulating layer or insulating sleeve.

[0017] It is also proposed that the safety device comprise a sensor unit for detecting at least one status parameter of the battery cell, and that the control unit comprise a microprocessor for characterizing the state of the battery cell based on the status parameter detected by the sensor unit. Such a configuration can advantageously further increase safety. In particular, the status of the battery cell can be specifically monitored, the presence of a critical condition can be reliably detected, and, in this case, a particularly precise triggering of the safety element can be enabled. Status parameters of the battery cell can include, for example, a temperature and / or a pressure and / or an electrical voltage and / or an electrical current and / or the like, without being limited thereto.To detect at least one status parameter, the sensor unit preferably comprises one or more sensors which, depending on the type of status parameter, are designed accordingly and arranged at corresponding locations on and / or in the battery cell and / or are electrically connected to the battery cell. Alternatively or additionally, it would also be conceivable for at least one switching element of the control unit, which is designed as a semiconductor component, for example as a transistor, to function as a sensor and be provided to automatically activate the heating unit when its threshold voltage, which is designed for a critical state of the battery cell, is exceeded, in particular without characterizing the state of the battery cell by the microprocessor.

[0018] Furthermore, it is proposed that the safety device have at least one insulator in order to electrically insulate the safety element and the heating element from one another. This can advantageously further increase safety. In particular, a short circuit between the safety element and the heating element can be prevented. Depending on the design of the safety element and / or the heating element, the insulator can be designed in various ways. For example, the insulator can be designed as part of a sheath if the heating element is designed as a wire. In one advantageous design, it is proposed that the carrier element acts as the insulator. Such a design can advantageously further improve efficiency, in particular with regard to material and / or manufacturing expenditure and the associated costs.

[0019] It is further proposed that the safety device comprise at least one reaction element, which is applied to the safety element at least in a partial area and is designed to react with the safety element under the thermal influence of the heating unit and to change its physical and / or chemical properties in order to promote triggering. Such a design can advantageously increase flexibility. In particular, the triggering characteristics of the safety element can be varied as needed, even while the protective element's structure remains otherwise unchanged.In the event of a critical condition of the battery cell, the reaction element can, for example, be designed to change the physical and / or chemical properties of the fuse element under the thermal influence of the heating unit by reducing the melting point of the contacting element, for example by alloying with the protective element, in order to promote triggering. The reaction element can, for example, be made of tin and, under the thermal influence of the heating unit, react with the protective element, which has copper and / or is made of copper, to form a tin bronze with a lower melting point than pure copper.It is also conceivable that, in the event of a critical condition of the battery cell, the reaction element is intended to change the physical and / or chemical properties of the protective element by increasing the brittleness of the protective element in order to promote fracture of the fuse element and thus its triggering. The reaction element can be made of gallium, for example, partially liquefy under the thermal influence of the heating unit and partially diffuse into the protective element, which has and / or is made of aluminum, and thus promote brittle fracture of the protective element and thus its triggering. The reaction element can be applied to the protective element in one or more partial areas, for example in the form of one or more soldering points or the like, or over its entire surface, for example by coating.

[0020] It is also proposed that the heating element and the fuse element be designed as copper layers and arranged in adjacent layers on the carrier element, wherein the copper layers may have different thicknesses. This advantageously enables a particularly flexible design of the fuse device and, in particular, simple adaptation to different requirements. It is also conceivable for some or all of the copper layers to have the same thickness. Preferably, the carrier element in this design is designed as a multi-layer printed circuit board and has at least two layers. If there are more than two layers, the fuse element is preferably arranged in an outer layer in order to enable a thickening of the fuse element designed as a copper layer, for example by means of galvanic processes, and thus an increase in the current-carrying capacity of the fuse element if necessary.In this embodiment, the securing device can, for example, also comprise a further securing element, which is then preferably arranged in a further outer layer. For example, the securing element can be arranged in an uppermost layer and the further securing element in a lowermost layer, with at least one further layer being arranged adjacent to the uppermost layer and / or the lowermost layer, on which the heating element and optionally at least one further heating element is / are arranged. The securing element and the heating element are advantageously formed as copper layers with different copper thicknesses. In this context, the term "copper thickness" refers to a unit from printed circuit board technology that describes the weight of a copper layer per area of ​​the circuit board and is specified in oz / ft 2 or g / m 2 . The thickness of the copper layer can be derived from the copper thickness.For example, the fuse element formed as a first copper layer can have a copper thickness of 2 oz / ft 2 , which corresponds to approximately 610 g / m 2 , and thus a thickness of approximately 70 µm. The heating element can, for example, be formed as a second copper layer with a copper thickness of 0.5 oz / ft 2 , which corresponds to approximately 152 g / m 2 , and thus have a copper thickness of approximately 17.5 µm.

[0021] Furthermore, it is proposed that the fuse element is provided for connection to an electrically positive terminal of the battery cell and that the control unit has a switching element which is designed as an NPN bipolar transistor or as an N-channel MOSFET. This can advantageously enable particularly simple activation of the heating unit in the critical state of the battery cell in the event that the fuse element is provided for connection to an electrically positive terminal of the battery cell. In an alternative advantageous embodiment, it is proposed that the fuse element is provided for connection to an electrically negative terminal of the battery cell and that the control unit has a switching element which is designed as a PNP bipolar transistor or as a P-channel MOSFET.This advantageously enables particularly simple activation of the heating unit in the critical state of the battery cell, in the event that the fuse element is provided for connection to an electrically negative terminal of the battery cell.

[0022] It is further proposed that the heating unit be provided for directly heating a region of the fuse element. This can advantageously enable particularly reliable triggering of the protective element in a critical state of the battery cell. The region of the fuse element for which the heating unit is provided for directly heating is preferably a so-called hotspot of the fuse element. Alternatively or additionally, it is proposed that the heating unit be provided for directly heating at least one surrounding region of the fuse element. If the heating unit is provided for directly heating at least one surrounding region of the fuse element, the fuse element can be indirectly heated by heat conduction, in particular via at least one further element, for example the carrier element.If the heating unit is provided exclusively for heating at least one area surrounding the fuse element, direct contact between the hot spot of the fuse element and the heating element can be advantageously avoided, which could otherwise lead to the temperature stability of the heating element being exceeded. If the heating unit is provided for heating at least one area surrounding the fuse element in addition to heating the area of ​​the fuse element, particularly reliable triggering can be further promoted.

[0023] It is further proposed that the safety element be designed to break an electrically conductive connection between the heating unit and the battery cell when triggered. This can advantageously further increase safety. In particular, it can prevent the heating unit from continuing to be supplied with electrical energy after the safety element has been triggered, and the associated hazards, such as a fire hazard, can be effectively prevented.

[0024] The invention further relates to a battery pack with at least one battery cell and with at least one safety device connected to the battery cell according to one of the previously described embodiments. Such a battery pack is characterized in particular by its advantageous properties with regard to safety, which can be achieved by the safety device according to the invention.

[0025] The invention also relates to a method for producing a safety device according to claim 14.

[0026] Using such a method, the security device according to the invention can be manufactured particularly simply and efficiently. The method preferably comprises at least two method steps. The security element can be applied to the circuit board, for example in a first method step, for example in the form of a copper track or the like, in particular by means of suitable processes known from the prior art. In a subsequent second method step, the heating element can be applied to the circuit board, for example in the form of another copper track or in the form of an electrical and / or electronic component, for example as a resistor, in particular a temperature-variable resistor, and / or as a semiconductor component or the like.

[0027] The safety device according to the invention is not intended to be limited to the application and embodiment described above. In particular, the safety device according to the invention may have a number of individual elements, components, units, and method steps that differs from the number stated herein to fulfill a function described herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily. drawing

[0028] Further advantages are shown in the following drawing description.

[0029] They show: Fig. 1 shows a battery pack with at least one battery cell and with a safety device connected to the battery cell in a schematic perspective view, Fig. 2 shows a schematic block diagram of the safety device, Fig. 3 shows the safety device in a schematic top view and a schematic side view, Fig. 4 shows a schematic process flow diagram to illustrate a method for producing the safety device, Fig. 5 shows a further example of a safety device in a schematic top view and a schematic side view, Fig. 6 shows a safety device according to the invention in two schematic top views and a schematic side view, Fig. 7 shows a further embodiment of a safety device in two schematic top views and a schematic side view, Fig. 8 shows a further embodiment of a safety device in a schematic representation and Fig.9A further embodiment of a safety device in a schematic representation. Description of the embodiments

[0030] Figure 1 shows a battery pack 50a with at least one battery cell 12a and with at least one securing device 10a connected to the battery cell 12a in a schematic perspective view. In the present case, the battery pack 50a is designed, for example, as a handheld power tool battery pack. Alternatively, however, it is also conceivable for the battery pack 50a to be designed as another battery pack that would be deemed appropriate by a person skilled in the art. The battery pack 50a has a housing 54a in which the at least one battery cell 12a and the securing device 10a are arranged.

[0031] The battery pack 50a can have a plurality of battery cells 12a, which are electrically connected in series and / or in parallel. The battery pack 50a can have a separate safety device 10a for each battery cell 12a. It is also conceivable that the safety device 10a is provided to protect multiple battery cells 12a of the battery pack 50a. For the sake of simplicity, the following description is limited to one safety device 10a for one battery cell 12a of the battery pack 50a.

[0032] Figure 2shows a schematic block diagram of the safety device 10a for the at least one battery cell 12a. The safety device 10a comprises a safety element 14a for interrupting a current flow from the battery cell 12a in a critical state of the battery cell 12a. A critical state can be, for example, but is not limited to, a short circuit of the battery cell 12a and / or overheating of the battery cell 12a and / or overpressure of the battery cell 12a and / or the like.

[0033] The safety device 10a further comprises a heating unit 16a. The heating unit 16a is coupled to the safety element 14a. The heating unit 16a has at least one heating element 22a. In the present case, the heating element 22a of the heating unit 16a is thermally coupled to the safety element 14a. The heating unit 16a is provided to assist in triggering the safety element 14a.

[0034] The securing device 10a has at least one carrier element 20a (see Figure 3) for receiving the securing element 14a and at least one heating element 22a of the heating unit 16a.

[0035] The battery cell 12a has an electrically positive terminal 42a and an electrically negative terminal 46a. The heating unit 16a is connected to at least one of the terminals 42a, 46a of the battery cell 12a for power supply.

[0036] The safety device 10a also includes a control unit 18a for activating the heating unit 16a in the critical state. The control unit 18a has at least one switching element 44a. In the critical state, the control unit 18a activates the heating unit 16a via the switching element 44a.

[0037] In the present case, the fuse element 14a is provided for connection to the electrically positive terminal 42a of the battery cell 12a, and the switching element 44a of the control unit 18a is designed as an NPN bipolar transistor or an N-channel MOSFET. Alternatively, the fuse element 14a can be provided for connection to the electrically negative terminal 46a of the battery cell 12a, in which case the switching element 44a of the control unit 18a is designed as a PNP bipolar transistor or a P-channel MOSFET.

[0038] The safety device 10a has a sensor unit 26a for detecting at least one status parameter of the battery cell 12a. A status parameter of the battery cell 12a can be, for example, a temperature and / or a pressure and / or an electrical voltage and / or an electrical current. The sensor unit 26a comprises one or more sensors (not shown) for detecting the at least one status parameter, which sensors can be arranged on and / or in the battery cell 12a and configured accordingly depending on the type of status parameter to be detected.

[0039] The control unit 18a has a microprocessor 28a. The microprocessor 28a is provided for characterizing the state of the battery cell 12a based on the status parameter detected by the sensor unit 26a. The microprocessor 28a is connected to the switching element 44a via a control line 56a of the control unit 18a. In an operating state of the safety device 10a, the microprocessor 28a monitors the at least one status parameter. If the at least one status parameter exceeds a predetermined limit value, for example, a permissible maximum temperature of the battery cell 12a, which is stored in a memory of the microprocessor 28a, the microprocessor detects that a critical state of the battery cell 12a exists and activates the heating unit 16a via the switching element 44a.

[0040] Figure 3 shows the securing device 10a in two schematic views. In an upper view of the Figure 3The securing device 10a is shown in a schematic plan view. A bottom view of the Figure 3 shows the safety device 10a in a schematic side view.

[0041] In the present case, the carrier element 20a of the securing device 10a is designed as a circuit board 24a. The securing element 14a and the at least one heating element 22a of the heating unit 16a are arranged together on the circuit board 24a.

[0042] The fuse device 10a has at least one insulator 30a to electrically insulate the fuse element 14a and the heating element 22a from each other. In this case, the carrier element 20a, i.e., the circuit board 24a, acts as the insulator 30a.

[0043] In the present embodiment, the heating unit 16a is provided for directly heating a region 48a of the securing element 14a.

[0044] The fuse element 14a is provided to sever an electrically conductive connection between the heating unit 16a and the battery cell 12a upon triggering. In the present case, the fuse element 14a is provided to sever an electrically conductive connection, via which the at least one heating element 22a of the heating unit 16a is connected to the positive connection point 42a of the battery cell 12a, upon triggering, so that when the fuse element 14a is triggered, not only a current flows from the battery cell 12a to external consumers, for example a drive unit of a handheld power tool (not shown), which is powered by the battery pack 50a (cf. Figure 1 ) is supplied with energy, but also a current flow from the battery cell 12a to the heating unit 16a is interrupted.

[0045] Figure 4shows a schematic process flow diagram of a method for producing the fuse device 10a for the battery cell 12a. The method comprises at least two process steps 58a, 60a. In a first process step 58a of the method, the fuse element 14a is applied to the circuit board 24a, for example as a narrowed copper track. In a second process step 60a of the method, the at least one heating element 22a of the heating unit 16a is applied to the circuit board 24a, for example in the form of a copper structure, which can be spiral or meander-shaped, for example.

[0046] In the Figures 5 to 9Five further embodiments of the invention are shown. The following descriptions and the drawings are essentially limited to the differences between the embodiments, whereby with regard to components with the same designation, in particular with regard to components with the same reference numerals, reference is also made to the drawings and / or the description of the other embodiments, in particular to the Figures 1 to 4 To distinguish the embodiments, the letter a is added to the reference numerals of the embodiment in the Figures 1 to 4 In the examples of the Figures 5 to 9 the letter a is replaced by the letters b to f.

[0047] Figure 5 shows a further embodiment of a securing device 10b for a battery cell 12b in two schematic views. In an upper view of the Figure 5The securing device 10b is shown in a schematic plan view. A bottom view of the Figure 5 shows the safety device 10b in a schematic side view.

[0048] Analogous to the previous embodiment, the safety device 10b has a safety element 14b for interrupting the flow of current from the battery cell 12b in a critical state of the battery cell 12b, and a heating unit 16b, which is coupled to the safety element 14b and is provided to assist in triggering the safety element 14b. The heating unit 16b has at least one heating element 22b.

[0049] The safety device 10b also has a control unit. The control unit of the safety device 10b is in the Figure 5 not shown and with regard to its operation, reference is made to the above description of the control unit 18a in the first embodiment.

[0050] The fuse device 10b, in turn, has at least one support element 20b for receiving the fuse element 14b and the at least one heating element 22b of the heating unit 16b. Analogous to the previous embodiment, the support element 20b is designed as a circuit board 24b, which simultaneously functions as an insulator 30b to electrically insulate the fuse element 24b and the heating element 22b from each other.

[0051] In contrast to the first embodiment, the heating unit 16b has, in addition to the heating element 22b, several additional heating elements 62b. The additional heating elements 62b are also arranged on the carrier element 20b, which is designed as a circuit board 24b.

[0052] A further difference from the previous embodiment is that the heating element 22b and the further heating elements 62b of the heating unit 16b are not designed as copper structures, but as temperature-variable resistors, for example as PTCs.

[0053] In the present exemplary embodiment, the heating unit 16b is again provided for directly heating a region 48b of the fuse element 14b. The heating of the region 48b of the fuse element 14b occurs in a critical state of the battery cell 12b by means of the heating element 22b of the heating unit 16b. Furthermore, the heating unit 16b is also provided for directly heating at least one surrounding region 52b of the fuse element 14b. The heating of at least one surrounding region 52b of the fuse element 14b occurs in a critical state of the battery cell 12b by means of the further heating element 62b of the heating unit 16b, whereby the triggering of the fuse element 14b is assisted by heat conduction of the circuit board 24b from the surrounding region 52b to the protective element 14b.It would also be conceivable that the heating element 22b and the heating elements 62b of the heating unit 16b are provided exclusively for a direct heating of at least one surrounding area 52b of the securing element 14b and are arranged accordingly, for example in order to avoid exceeding a temperature stability of the heating elements 22b, 62b in the critical state.

[0054] Figure 6 shows a further embodiment of a securing device 10c for a battery cell 12c in three schematic views.

[0055] Analogous to the previous embodiments, the safety device 10c comprises a safety element 14c for interrupting the flow of current from the battery cell 12c in a critical state of the battery cell 12c, and a heating unit 16c, which is coupled to the safety element 14c and is provided to assist in triggering the safety element 14c. The heating unit 16c, in turn, comprises at least one heating element 22c.

[0056] The fuse device 10c, analogous to the previous embodiments, has at least one support element 20c for receiving the fuse element 14c and the at least one heating element 22c of the heating unit 16c. The support element 20c is designed as a circuit board 24c, which simultaneously functions as an insulator 30c to electrically insulate the fuse element 24c and the heating element 22c from each other.

[0057] The safety device 10c also has a control unit. The control unit of the safety device 10c is in the Figure 6 not shown and with regard to its operation, reference is made to the above description of the control unit 18a in the first embodiment.

[0058] According to the invention, the printed circuit board 24c is multi-layered, in the present case, for example, four-layered. A top view of the Figure 6 shows a first layer 36c of the circuit board 24c in a schematic plan view. The fuse element 14c is formed as a first copper layer 66c and is arranged on the first layer 36c of the circuit board 24c.

[0059] A middle view of the Figure 6 shows a second layer 38c of the circuit board 24c in a schematic plan view. The heating element 22c of the heating unit 16c is formed as a second copper layer 68c and arranged on the second layer 38c of the circuit board 24c.

[0060] A bottom view of the Figure 6 shows a schematic side view of the carrier element 20c, designed as a multilayer circuit board 24c. The heating element 22c and the fuse element 24c are arranged in adjacent layers 36c, 38c on the carrier element 20c.

[0061] The first copper layer 66c and the second copper layer 68c have different thicknesses. In the present case, the fuse element 14c, formed as the first copper layer 66c, has a greater thickness than the heating element 22c, formed as the second copper layer 68c. For example, the first copper layer 66c can be applied to the first layer 36c of the circuit board 24c with a copper thickness of 2 oz / ft 2 , which corresponds to approximately 610 g / m 2 , and can have a thickness of approximately 70 µm, and the second copper layer 68c can be applied to the second layer 38c of the circuit board 24c with a copper thickness of 0.5 oz / ft 2 , which corresponds to approximately 152 g / m 2 , and can have a thickness of approximately 17.5 µm.

[0062] In this case, the heating unit 16c has a further heating element 62c, which is applied to a third layer 40c of the circuit board 24c as a third copper layer 72c. The thickness of the third copper layer 72c corresponds in this case to the thickness of the second copper layer 68c.

[0063] The fuse device 10c in this case has a further fuse element 70c, which is applied to a fourth layer 64c of the printed circuit board 24c as a fourth copper layer 74c. The thickness of the fourth copper layer 74c corresponds in this case to the thickness of the first copper layer 66c. The further heating element 62c of the heating unit 16c is provided in this case to assist in triggering the further fuse element 70c. The further fuse element 70c and the further heating element 62c are arranged in mutually adjacent layers 40c, 64c on the carrier element 20c.

[0064] In the present case, the fuse element 14c and the further fuse element 70c of the fuse device 10c are each arranged in the outer layers, i.e., in the first layer 36c and the fourth layer 64c, of the circuit board 24c. This allows for a thickening of the first copper layer 66c and / or the fourth copper layer 74c, for example, by means of galvanic processes, in order to increase the current-carrying capacity of the fuse element 14c and / or the further fuse element 70c, if necessary.

[0065] Figure 7 shows a further embodiment of a securing device 10d for a battery cell 12d in three schematic views.

[0066] Analogous to the previous embodiments, the safety device 10d comprises a safety element 14d for interrupting the flow of current from the battery cell 12d in a critical state of the battery cell 12d, and a heating unit 16d, which is coupled to the safety element 14d and is provided to assist in triggering the safety element 14d. The heating unit 16d, in turn, comprises at least one heating element 22d.

[0067] The fuse device 10d, analogous to the previous embodiments, has at least one carrier element 20d for receiving the fuse element 14d and the at least one heating element 22d of the heating unit 16d. The carrier element 20d is designed as a circuit board 24d, which simultaneously functions as an insulator 30d to electrically insulate the fuse element 24d and the heating element 22d from each other.

[0068] The safety device 10d also has a control unit which is located in the Figure 7 is not shown, so that with regard to its operation reference is made to the above description of the control unit 18a in the first embodiment.

[0069] Analogous to the previous embodiment, the printed circuit board 24d is formed in multiple layers. The safety device 10d has a substantially identical structural design to the safety device 10c with respect to the printed circuit board 24d, which is why reference is made to the above description of the Figure 6 referred to.

[0070] In contrast to the previous embodiment, the safety device 10d has at least one reaction element 32d. The reaction element 32d is designed to react with the safety element 14d under the thermal influence of the heating unit 16d and to change its physical and / or chemical properties in order to promote the triggering of the safety element 14d.

[0071] In the present case, the reaction element 32d is applied to the securing element 14d in a partial area 34d. Alternatively or additionally, the reaction element 32d could also be applied to other partial areas (not shown) of the securing element 14d or over the entire surface of the securing element 14d, for example, as a coating.

[0072] In the present case, the reaction element 32d is made of tin. The reaction element can, for example, be applied as a soldering point to the fuse element 14d. Under the thermal influence of the heating unit 16d, the reaction element 32d made of tin reacts with the fuse element 14d, formed as a copper layer 66d, in the partial region to form a tin bronze, which has a lower melting point than the pure copper of the fuse element 14d.

[0073] The reaction element 32d is only in the present embodiment of the Figure 7 shown, wherein the person skilled in the art recognizes that the functioning of the reaction element 32d as such is not limited to the specific structure of the safety device 10d and can also be transferred analogously to all of the preceding and subsequent embodiments.

[0074] Figure 8shows a further embodiment of a securing device 10e for a battery cell 12e in a schematic representation.

[0075] Analogous to the previous embodiments, the safety device 10e comprises a safety element 14e for interrupting the flow of current from the battery cell 12e in a critical state of the battery cell 12e, and a heating unit 16e, which is coupled to the safety element 14e and is provided to assist in triggering the safety element 14e. The heating unit 16e, in turn, comprises at least one heating element 22e, in this case precisely one.

[0076] The securing device 10e has, analogously to the previous embodiments, at least one carrier element 20e for receiving the securing element 14e and the at least one heating element 22e of the heating unit 16e.

[0077] In contrast to the previous embodiments, the securing element 14e is formed integrally with the carrier element 14e. In this case, the securing element 14e is designed as a metal strip securing element.

[0078] The heating element 22e of the heating unit 16e is embodied as an electrically insulated wire and is placed directly on the fuse element 14e, for example, wound around the fuse element 14e. An insulating layer (not shown) of the wire simultaneously functions as an insulator of the fuse device 10e to electrically insulate the fuse element 14e and the heating element 22e from each other.

[0079] Figure 9 shows a further embodiment of a securing device 10f for a battery cell 12f in a schematic representation.

[0080] Analogous to the previous embodiments, the safety device 10f comprises a safety element 14f for interrupting the flow of current from the battery cell 12f in a critical state of the battery cell 12f, and a heating unit 16f, which is coupled to the safety element 14f and is provided to assist in triggering the safety element 14f. The heating unit 16f, in turn, comprises at least one heating element 22f, in this case precisely one.

[0081] The securing device 10f has, analogously to the previous embodiments, at least one carrier element 20f for receiving the securing element 14f and the at least one heating element 22f of the heating unit 16f.

[0082] As in the previous embodiment of the Figure 8 The securing element 14f is formed integrally with the carrier element 14f. The securing element 14f is designed here as a metal strip securing element.

[0083] The heating element 22f of the heating unit 16f is, in contrast to the previous embodiment, the Figure 8 formed directly from branched parts of the securing element 14f.

[0084] The fuse device 10f has at least one insulator 30f to electrically insulate the fuse element 14f and the heating element 22f from each other. In this case, the insulator 30f is formed as an insulating layer arranged between the fuse element 14f and the heating element 22f of the heating unit 16f.

Claims

1. Fuse device (10a-f) for at least one battery cell (12a), comprising a fuse element (14a-f) for interrupting a current flow from the battery cell (12a) in a critical state of the battery cell (12a), comprising a heating unit (16a-f), which is thermally and electrically and / or mechanically coupled to the fuse element (14a-f) and is provided for assisting tripping of the fuse element (14a-f), and comprising a control unit (18a) for activating the heating unit (16a-f) in the critical state, characterized in that the fuse device (10a-f) has at least one carrier element (20a-f) for receiving the fuse element (14a-f) and at least one heating element (22a-f) of the heating unit (16a-f), wherein the carrier element (20a-d) is in the form of a multi-layer printed circuit board (24a-d), wherein the heating unit (16a-f) and the fuse element (14a-f) are arranged in adjacent layers of the carrier element (20a-f).

2. Fuse device (10e; 10f) according to Claim 1, characterized in that the fuse element (14e; 14f) is formed in one piece with the carrier element (20e; 20f).

3. Fuse device (10a-f) according to either of the preceding claims, characterized in that the fuse device (10a-e) has a sensor unit (26a) for detecting at least one status parameter of the battery cell and the control unit has a microprocessor (28a) for characterizing the state of the battery cell (12a-f) based on the status parameter detected by the sensor unit (26a).

4. Fuse device (10a-f) according to any of the preceding claims, characterized in that the fuse device (10a-f) has at least one insulator (30a-f) in order to electrically insulate the fuse element (14a-f) and the heating element (22a-f) from each other.

5. Fuse device (10a-d) according to Claim 4, characterized in that the carrier element (20a-d) acts as the insulator (30a-d).

6. Fuse device (10d) according to any of the preceding claims, characterized in that the fuse device (10d) has at least one reaction element (32d), which is mounted on the fuse element (14d) at least in a sub-region (34d) and is intended to react with the fuse element (14d) under the thermal influence of the heating unit (16d) and to change the physical and / or chemical properties of the fuse element in order to promote tripping.

7. Fuse device (10c; 10d) according to any of the preceding claims, characterized in that the heating element (22c; 22d) and the fuse element (14d; 14d) are in the form of copper layers (66c, 68c; 66d; 68d) and are arranged in mutually adjacent layers (36c, 38c; 36d; 38d) on the carrier element (20c; 22d).

8. Fuse device (10a-f) according to any of the preceding claims, characterized in that the fuse element (14a-f) is intended to be connected to an electrically positive connection (42a-f) of the battery cell (12a-f) and in that the control unit (18a) has a switching element (44a), which is in the form of an NPN bipolar transistor or in the form of an N-channel MOSFET.

9. Fuse device (10a-f) according to any of Claims 1 to 8, characterized in that the fuse element (14a-f) is intended to be connected to an electrically negative connection (46a) of the battery cell and in that the control unit has a switching element (44a), which is in the form of a PNP bipolar transistor or in the form of a P-channel MOSFET.

10. Fuse device (10a-f) according to any of the preceding claims, characterized in that the heating unit (16a-f) is intended to directly heat a region (48a) of the fuse element (14a-f).

11. Fuse device (10b) according to any of the preceding claims, characterized in that the heating unit (16b) is intended to directly heat at least a surrounding region (52b) of the fuse element (14b).

12. Fuse device (10a-f) according to any of the preceding claims, characterized in that the fuse element (14a-f) is intended to disconnect an electrically conductive connection between the heating unit (16a-f) and the battery cell (12a-f) in the event of tripping.

13. Battery pack (50a) comprising at least one battery cell (12a-f) and comprising at least one fuse device (10a-f) according to any of the preceding claims connected to the battery cell (12a-f).

14. Method for producing a fuse device (10a-d) according to any of Claims 1 to 12, wherein a fuse element (14a-d) and at least one heating element (22a-d) of a heating unit (16a-d) are mounted on a printed circuit board (24a-d).