Sensor fuse for an electrical battery assembly

Abstract

Vehicle performance system, comprehensive: a battery arrangement (100) comprising at least one battery having a busbar (104) connected to an electric bus; and a conductive lead (108) of a sensor which is welded to the busbar (104) to form a connection defined by a plurality of welds (110) wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead (108) such that short-circuit current from the battery arrangement (100) melts the connection to protect the sensor.

Description

TECHNICAL FIELD

[0001] This disclosure relates to sensor fuses for electrical battery assemblies. GENERAL STATE OF THE ART

[0002] Electric and hybrid vehicles may include battery assemblies or banks to store and release electrical energy. Battery voltage may be monitored by attaching sensors. The sensors may be twisted between busbars having different polarities. US 2016 / 0 133 908 A1 discloses a busbar for a battery connection system. DE 10 2015 202 144 A1 discloses an integrated voltage sensing and busbar system and a method for vehicles with a traction battery. US 2012 / 0 126 929 A1 discloses a power fuse device and a battery system including this device. SUMMARY

[0003] A vehicle power system may include a battery assembly having at least one battery with a bus bar connected to an electrical bus. The power system may also include a conductive lead of a sensor welded to a bus bar to form a connection defined by a plurality of seams, wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead such that short-circuit current from the battery assembly melts the connection to protect the sensor. The seams may be arranged along an axis of the conductive lead. The seams may be arranged perpendicular to an axis of the conductive lead. The lead may be a 22-gauge wire. The seams may have a surface area equivalent to a 26-gauge wire. The net cross-sectional area of ​​the plurality may be between 60-70% of the cross-sectional area of ​​the lead.

[0004] A method may include joining a conductive lead of a sensor to a bus bar of a battery assembly via a laser weld to form a joint defined by a plurality of laser welds, wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead such that short-circuit current from the battery assembly melts the joint to protect the sensor. The welds may be arranged along an axis of the conductive lead. The welds may be arranged perpendicular to an axis of the conductive lead. The lead may be a 22-gauge wire. The welds may have a surface area equivalent to a 26-gauge wire. The net cross-sectional area of ​​the plurality may be between 60-70% of the cross-sectional area of ​​the lead.

[0005] A vehicle power system may include a battery assembly including at least one battery having a bus bar connected to an electrical bus. The system may further include a conductive lead of a sensor laser-welded to a bus bar to form a connection defined by a plurality of seams, wherein a net cross-sectional area of ​​the plurality is less than a cross-sectional area of ​​the lead and is oriented in a free-falling position such that short-circuit current from the battery assembly melts the connection to protect the sensor and separates the lead and the bus bar. The seams may be arranged along an axis of the conductive lead. The seams may be arranged perpendicular to an axis of the conductive lead. The lead may be a 22-gauge wire. The seams may have a surface area corresponding to a 26-gauge wire.The net cross-sectional area of ​​the multitude can be between 60-70% of the cross-sectional area of ​​the supply line. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 depicts a battery arrangement configured in a series circuit; Fig. Figure 2 shows a series of seams of a laser weld between a wire and a busbar; Fig. Figure 3A depicts a series of seams of a laser weld transverse to an axis of the wire; Fig. Figure 3B depicts a series of seams of a laser weld along an axis of the wire; Fig. 3C depicts a series of sutures arranged in a circular or triangular configuration; and Fig. Figure 4 illustrates a process for laser welding a busbar and a conductive supply line. DETAILED DESCRIPTION

[0006] Embodiments of the present disclosure are described herein. It is to be understood that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or reduced to show details of particular components. Accordingly, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. Those of ordinary skill in the art will recognize that various features illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments not explicitly illustrated or described.The combinations of features illustrated provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desirable for particular applications or implementations.

[0007] Power modules or battery assemblies may include a large number of battery cells. Each of the cells may be electrically connected in series to increase the electrical potential between the terminals of the assembly. Each of the cells may be connected using a bus bar between the individual positive and negative terminals to connect the voltage. The voltage of each bus bar may be monitored absolutely or relatively with a controller or sensor. The controller may be electrically connected to each of the bus bars using a flat flexible cable (FFC). The FFC may be connected to each individual bus bar on a given side of the battery assembly to provide voltage feedback to a controller. The FFC may include multiple individual conductors. The FFC may provide a path for short-circuit current to escape between the bus bars.

[0008] Fixed terminals provide a rigid electrical connection between sensor leads, capable of carrying a current equal to the wire's cross-sectional area. These sensor leads can provide a path for short circuits. Installing fuses can protect against short circuits. Installing standard fuses can increase manufacturing costs and introduce a single point of failure. To overcome these problems, the sensor lead and busbar can be welded together in a manner that creates a fuse.

[0009] A fuse can be created using tungsten inert gas (TIG) welding, metal inert gas (MIG) welding, or arc welding. Welds can be used to create a desirable connection between the conductive lead and the busbar. These methods can create undesirable welds. Laser welding can fuse the sensor lead and busbar. Laser welding can create a joint that has a net cross-sectional area smaller than the sensor lead. The smaller cross-sectional area ensures that under high current, separation of the sensor lead and busbar will occur as the joint seams melt.

[0010] The sensor lead can be connected to the busbar in any orientation or configuration. The connection can be located on either side of the busbar. For example, the sensor lead can be welded to a lower portion of the busbar so that gravity ensures separation of the sensor lead and the busbar after the fuse blows. The sensor lead can be welded to a side portion of the busbar so that tension and gravity pull the sensor lead away from the busbar after overcurrent protection is provided. Additionally, the sensor lead can be located on the upper portion of the busbar.

[0011] The seams used to connect the sensor lead and the busbar can have different spatial arrangements. The seams can be arranged along an axis of the sensor lead. The seams can be arranged perpendicular to an axis of the sensor lead. The seams can be arranged in a geometric shape that provides adequate strength and produces the correct net cross-sectional area. The seams can be arranged so that they have a net cross-sectional area that is smaller than the cross-sectional area of ​​the sensor lead. For example, the sensor lead can be a 22-gauge wire that has a cross-sectional area of ​​0.326 mm 2 One large seam or a plurality of seams can be used to create a fusion joint having a cross-sectional area of ​​0.14 mm 2 which corresponds to the cross-sectional area of ​​a 26-gauge wire.

[0012] Now with reference to Fig. 1, a battery assembly or subassembly 100 is shown. A plurality of battery modules 102 are arranged to form a battery assembly 100. The battery modules 102 may be located within a battery assembly carrier 132. The carrier 132 may be fixed to a support unit using through-holes 130. The battery modules 102 are electrically connected in series using bus bars 104. The battery modules 102 may be connected in parallel. A gap may exist between each of the battery modules 102 to form an assembly 100. An FFC 106 may extend over some or a portion of the battery modules 102. The FFC 106 may be associated with a plurality of conductors or conductive leads 108. Each conductive lead 108 of the FFC 106 may be connected to some or all of the bus bars 104. As shown, the conductive leads 108 may be connected on top of the bus bars 104.The conductive leads 108 may also be connected to the bottom or sides of the bus bars 104. Although the conductive leads 108 are shown having uniform terminations, they may be connected in various orientations relative to each other. The conductive leads 108 may be oriented in a free-falling position, such that the separation between the bus bar 104 and the conductive lead 108 occurs during a short circuit. The separation may occur due to mechanical stress on the conductive lead 108 or the FFC 106, or due to gravity.

[0013] Now with reference to Fig. 2 shows a laser weld 111 formed by a laser beam 112 between a busbar 104 and a conductive lead 108. The laser weld 111 may be arranged along an axis 113 of the conductive lead 108. The weld 111 may include a plurality of seams 110. The seams 110 may overlap slightly. The seams 110 may have a uniform or non-uniform diameter 114. The weld 111 may have a surface area smaller than the surface area of ​​the conductive lead 108. The surface area of ​​the weld 111 may be 60-70% of the surface area of ​​the conductive lead 108.

[0014] Now with reference to the Fig. 3A-C shows a variety of laser welding orientations and configurations. Fig. 3A discloses a conductive lead 108 laser welded 111 to a busbar 104. The laser weld 111 includes seams 110 having an orientation perpendicular to the axis 113 of the conductive lead 108. Fig. 3B discloses a conductive lead 108 laser welded 111 to a busbar 104. The laser weld 111 includes seams 110 having an orientation along the axis 113 of the conductive lead 108. Fig. 3C discloses a conductive lead 108 laser welded 111 to a busbar 104. The laser weld 111 includes seams 110 having a circular orientation 115.

[0015] Now with reference to Fig.4, a flowchart 200 is disclosed. The flowchart 200 begins at step 202. At step 204, the sensor lead is aligned with the busbar in an orientation that ensures free fall of the sensor lead after the fuse or weld is consumed, meaning that at least a portion of the sensor has a free-falling posture. The free-falling posture ensures that the lead is interrupted during a short circuit by physically separating the sensor lead and the busbar. At step 206, the sensor lead is attached to the busbar using a staple or adhesive to ensure an effective laser weld. At step 208, the sensor lead is connected to the busbar using a seam of a laser weld.At step 210, the joint can be inspected for quality and to ensure that a weld of the correct size and weld surface area is used. If the surface area is inadequate, the laser can be realigned at step 212. If the resulting surface area has adequate attachment features and is not excessively large, the process terminates at step 214.

[0016] The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments may be combined to form other embodiments of the invention that may not be expressly described or illustrated.While various embodiments may be described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, one of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve the desired overall system attributes, depending on the particular application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, operability, weight, manufacturability, ease of assembly, etc.As such, embodiments that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for certain applications.

Claims

[1] Vehicle performance system comprising: a battery assembly (100) including at least one battery having a bus bar (104) connected to an electrical bus; and a conductive lead (108) of a sensor welded to the bus bar (104) to form a connection defined by a plurality of seams (110), wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead (108) such that short-circuit current from the battery assembly (100) melts the connection to protect the sensor. [2] The vehicle power system of claim 1, wherein the seams (110) are arranged along an axis (113) of the conductive lead (108). [3] The vehicle power system of claim 1, wherein the seams (110) are arranged perpendicular to an axis (113) of the conductive lead (108). [4] The vehicle power system of claim 1, wherein the lead (108) is a 22-gauge wire. [5] The vehicle power system of claim 4, wherein the seams (110) have a surface area corresponding to a 26-gauge wire. [6] The vehicle power system of claim 1, wherein the net cross-sectional area of ​​the plurality is between 60-70% of the cross-sectional area of ​​the supply line (108). [7] Method comprising: Connecting a conductive lead (108) of a sensor to a bus bar (104) of a battery assembly (100) via a laser weld to form a connection defined by a plurality of laser welds (110), wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead (108) such that short-circuit current from the battery assembly (100) melts the connection to protect the sensor. [8] The method of claim 7, wherein the seams (110) are arranged along an axis (113) of the conductive lead (108). [9] The method of claim 7, wherein the seams (110) are arranged perpendicular to an axis (113) of the conductive lead (108). [10] The method of claim 7, wherein the lead (108) is a 22-gauge wire. [11] The method of claim 10, wherein the seams (110) have a surface area corresponding to a 26-gauge wire. [12] The method of claim 7, wherein the net cross-sectional area of ​​the plurality is between 60-70% of the cross-sectional area of ​​the supply line (108). [13] Vehicle performance system comprising: a battery assembly (100) including at least one battery having a bus bar (104) connected to an electrical bus; and a conductive lead (108) of a sensor laser welded to the bus bar (104) to form a connection defined by a plurality of seams (110), wherein a net cross-sectional area of ​​the plurality is smaller than a cross-sectional area of ​​the lead (108) and is oriented in a free-falling position such that short-circuit current from the battery assembly (100) melts the connection to protect the sensor and separates the lead (108) and the bus bar (104). [14] The vehicle power system of claim 13, wherein the seams (110) are arranged along an axis (113) of the conductive lead (108). [15] The vehicle power system of claim 13, wherein the seams (110) are arranged perpendicular to an axis (113) of the conductive lead (108).

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