CN114883754A

CN114883754A - Busbar, corresponding battery system and vehicle

Info

Publication number: CN114883754A
Application number: CN202110163055.4A
Authority: CN
Inventors: 商光路; S·莱纳特
Original assignee: Audi Stock Co
Current assignee: Audi Stock Co
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2022-08-09

Abstract

The invention provides a bus bar for a battery, a corresponding battery system and a vehicle. The busbar includes a main body region and a plurality of extensions extending therefrom and spaced apart in a longitudinal direction thereof, each extension having an end for connecting the battery and a connecting portion connecting the end to the main body region, each connecting portion including a first portion extending from the main body region in an extending direction of the extension and a second portion between the respective end and the first portion, the first portion having a cross section in the longitudinal direction that gradually decreases along the extending direction, the second portion having a cross section in the longitudinal direction that gradually increases along the extending direction, and an interface of the first portion with the main body region and an interface of the second portion with the end being smooth. With the invention, turbulence and the consequences associated therewith can be completely or partially avoided while increasing the thermal resistance of the busbar to reduce heat propagation.

Description

Busbar, corresponding battery system and vehicle

Technical Field

The present invention relates to a bus bar, and more particularly, to a bus bar for a battery, and a corresponding battery system and vehicle.

Background

In a high-voltage battery system, a bus bar is generally used to connect two or more batteries. According to circumstances, the batteries may be connected in parallel and/or in series. The main function of the bus bar is to make electrical connections. The busbars are usually made of metal, which means that they have a good thermal conductivity. In some cases, a battery connected by a bus bar may be thermally runaway, and how to reduce the heat spread is a problem.

In response to the above problems, the existing solution is to reduce the cross section of a certain portion of the bus bar, thereby reducing the heat spread by increasing the thermal resistance. However, this solution leads to additional drawbacks. For example, in the case of this solution, the region or portion of the bus bar for connection between the batteries may have an increased resistance, which is disadvantageous. Further, in this case, the bus bar has a cross section of varying size in some portions, and such a transition due to the variation in the cross-sectional size may cause turbulence and adversely affect the electromagnetic compatibility performance of the bus bar.

Fig. 3 shows a portion of a prior art buss bar with battery terminals attached thereto. As shown, current, i.e., the main current shown in fig. 3, flows from the battery terminal attached to the end of an extension of the bus bar, toward the main region 101 'of the bus bar via the connecting portion 1021' of the extension; accompanying this, turbulence as shown in fig. 3 is caused due to the sharp transition caused by the sharp change in cross section at the interface between the end of the extension and the connecting part 1021'.

Disclosure of Invention

It is an object of the present invention to provide a solution that solves or alleviates the above mentioned problems.

Specifically, according to a first aspect of the present invention, there is provided a bus bar for a battery, comprising:

a body region; and

a plurality of extensions extending from the body region in one extension direction and spaced apart in a longitudinal direction of the body region, each of the plurality of extensions having an end portion for connecting a battery and a connection portion connecting the end portion to the body region, for each of the plurality of extensions:

the connecting portion thereof includes a first portion extending from the main body region in the extending direction and a second portion between an end thereof and the first portion, wherein:

the cross-section of the first section in the longitudinal direction gradually decreases along the direction of extension, the cross-section of the second section in the longitudinal direction gradually increases along the direction of extension, and the interface of the first section with the body region and the interface of the second section with the end portion are smooth.

According to a second aspect of the present invention, there is provided a battery system including a plurality of batteries and the above-described bus bar, the plurality of batteries being connected in parallel and/or in series by the bus bar, one of a positive electrode terminal and a negative electrode terminal of each of the plurality of batteries being connected to an end of a corresponding one of the extension portions of the bus bar.

According to a third aspect of the invention, a vehicle is provided that includes the battery system described above.

According to the present invention, a bus bar has a main body region and a plurality of extensions extending from the main body region and spaced apart in a longitudinal direction of the main body region for connecting different batteries, each extension having an end for connecting a corresponding battery and a connecting portion connecting the end to the main body region, the connecting portion of each extension being inventively provided to have a novel design in the extending direction and the longitudinal direction such that a region or portion of the bus bar for connection between batteries has a reduced cross section in at least one location while avoiding sharp transitions or transitions due to changes in cross section. In this way, turbulence and the consequences associated therewith, such as a negative influence on the electromagnetic compatibility properties of the busbar, can be completely or partially avoided while increasing the thermal resistance of the busbar in order to reduce heat propagation.

Drawings

Non-limiting and non-exhaustive embodiments of the present invention are described by way of example with reference to the following drawings, in which:

FIG. 1 is a schematic diagram illustrating a buss bar according to one embodiment of the present invention;

fig. 2 is a schematic view illustrating a portion of a bus bar to which battery terminals are attached according to an embodiment of the present invention;

fig. 3 schematically shows a portion of a prior art busbar to which battery terminals are attached.

Detailed Description

In order to make the above and other features and advantages of the present invention more apparent, the present invention is further described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are for purposes of illustration only and are not intended to be limiting, as those of ordinary skill in the art will recognize.

The features described herein may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, the embodiments described herein are provided merely to illustrate some of the many possible ways to implement the structures and/or methods described herein. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the specific details need not be employed to practice the present invention. In some instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present invention.

As used herein, the term "and/or" includes any one of the associated listed items and any combination of any two or more of the associated listed items.

Although terms such as "first" and "second" may be used herein to describe various members, components, portions or elements, these members, components, portions or elements are not limited by these terms. Rather, these terms are only used to distinguish one element, component, portion or element from another element, component, portion or element. Thus, a first member, component, part or element referred to herein may also be termed a second member, component, part or element without departing from the teachings of the present invention.

Spatially relative terms, such as "upper," "lower," "left," "right," "above," "below," "upper," "lower," and "side," may be used herein to facilitate describing one element, component, portion, or element's relationship to another element, component, portion, or element as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, a component, part, or element described as being "on" or "upper" relative to another component, part, or element would be "on" or "lower" relative to the other component, part, or element. Thus, the term "upper" encompasses an upper orientation and a lower orientation, depending on the spatial orientation of the device. The device may also be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of the disclosure. The terms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," and "having" specify the presence of stated features, operations, components, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, operations, components, elements, and/or combinations thereof.

The invention provides a bus bar for a battery. In general, the bus bar includes: a body region; and a plurality of extensions extending from the main body region in one extension direction and spaced apart in a longitudinal direction of the main body region, each extension having an end portion for connecting the battery and a connection portion connecting the end portion to the main body region. For each of the plurality of extensions, the present invention proposes the following inventive design: the connecting portion thereof includes a first portion extending from the main body region in the extending direction and a second portion between an end thereof and the first portion; the cross-section of the first section in the longitudinal direction gradually decreases along the direction of extension, the cross-section of the second section in the longitudinal direction gradually increases along the direction of extension, and the interface of the first section with the body region and the interface of the second section with the end portion are smooth. Here, the interface being smooth should be understood as: the interface has a smooth profile, being smooth throughout, with no sharp corners.

Fig. 1 schematically illustrates a bus bar 100 according to an embodiment of the present invention. As shown in fig. 1, the busbar 100 comprises a main body region 101 and 6 extensions 102 extending from the main body region in an extension direction 120 and spaced apart in a longitudinal direction 110 of the main body region, the extension direction 120 being orthogonal to the longitudinal direction 110.

Each extension 102 has an end portion 1022 for connecting a battery and a connecting portion 1021 connecting the end portion 1022 to the main body region 101.

The structure of each connection part 1021 may be as shown in fig. 2, which will be described later.

The cross-section of the end 1022 along the plane defined by the extension direction 120 and the longitudinal direction 110 is generally circular. The cross section of the end portion 1022 in the longitudinal direction 110 may have a shape with a smooth outer edge, particularly a closed shape, and gradually increases and then gradually decreases along the extending direction 120.

The main body region of the busbar of the present invention may define a major plane. The extension of the busbar can lie in this main plane or in a plane parallel to it, i.e. the extension direction of the extension is parallel to the main plane, but this is not essential. The extension and the main body region of the busbar of the invention may lie in different planes, as desired, for example the extension may be at an angle to the main plane in which the main body region lies, which may be 90 degrees or an angle greater than 90 degrees or less than 90 degrees.

Although the extension direction of the extension is orthogonal to the longitudinal direction of the main body region in fig. 1, this is not essential. If desired, the direction of extension may not be orthogonal to the longitudinal direction, for example may be at an acute angle to the latter.

In addition, the number of the extended portions of the bus bar of the present invention may be arbitrary, depending on the specific case, and is not limited to 6 shown in fig. 1. For example, the number of extensions may be determined based on, among other factors, the number of batteries that the buss bar in which they are intended to be connected.

Fig. 2 schematically illustrates a portion of a main body region 101 of a bus bar, an extension portion extending therefrom, and a battery terminal attached to an end of the extension portion, according to an embodiment of the present invention. The extending portion extends in the extending direction 120, and the connecting portion thereof includes three portions, i.e., a first portion 1021a extending from the main body region 101 in the extending direction 120, a third portion 1021c extending from the first portion 1021a in the extending direction 120, and a second portion 1021b between the third portion 1021c and the corresponding end portion. The first portion 1021a has a generally trapezoidal cross-section along a plane defined by the extending direction 120 and the longitudinal direction 110, the trapezoid being an inverted trapezoid, i.e., wide at the top and narrow at the bottom along the extending direction 120. A cross section of the first portion 1021a in the longitudinal direction 110 of the body region may be in a shape with smooth outer edges, in particular a closed shape, and gradually decreases in the extension direction 120. The tapering of the cross section of the first portion 1021a in the longitudinal direction 110 along the extension direction 120 may comprise a tapering of the area and/or the outer edge length of the cross section along the extension direction 120. The second portion 1021b is generally trapezoidal in cross-section along a plane defined by the extension direction 120 and the longitudinal direction 110, the trapezoid being narrow at the top and wide at the bottom along the extension direction 120. The second portion 1021b may have a cross-section in the longitudinal direction 110 in a shape with a smooth outer edge, in particular a closed shape, and gradually increase along the extension direction 120. The increasing of the cross section of the second portion 1021b in the longitudinal direction 110 along the extension direction 120 comprises a increasing area and/or outer edge length of the cross section along the extension direction 120. A cross-section of the third portion 1021c along a plane defined by the extension direction 120 and the longitudinal direction 110 is generally square. Herein, "square" includes square and rectangular. A cross section of the third portion 1021c in the longitudinal direction 110 is constant in size along the extension direction 120, which includes a constant area and/or constant outer edge length of the cross section along the extension direction 120. The first portion, the second portion, and the third portion may each have the same or different cross-sectional shape in the longitudinal direction.

Although fig. 1 and 2 show that the upper first portion and the lower second portion of each connection are connected by a third portion between the second portion and the first portion, this is not essential. According to circumstances, the upper first portion and the lower second portion of each connection portion may be directly connected or connected through two or more additional portions; in the latter case, these additional portions may be designed to have different cross-sectional designs in the extension direction of the extension, in the longitudinal direction of the main body region and/or along a plane defined by the extension direction and the longitudinal direction. In either case, the transition between adjacent ones of the portions of the connection may be treated to have a smooth profile, i.e., the outer surface of the transition is smooth throughout, free of sharp corners. In addition, in either case, the cross-section of each connection and at least one or some of its parts (such as the first, second and/or third part) in the longitudinal direction of the body region may be of a shape with smooth outer edges, in particular a closed shape. In addition, in either case, the side or sides of the cross-section of each connection and at least one or some of its portions (e.g., the first portion, the second portion, and/or the third portion) along the plane defined by the extension direction and the longitudinal direction of the body region may not necessarily be straight, but may be smoothly curved-i.e., the side or sides are curved and everywhere smooth, free of sharp corners.

Herein, a shape may be considered to be "with a smooth outer edge" if its outer edge defining the shape is smooth, free of sharp corners throughout. Shapes with smooth outer edges include, for example, but are not limited to, ovals, circles, shapes consisting of semi-circles and semi-ovals, or other shapes such as irregular shapes with smooth outer edges.

Although fig. 1 and 2 show that the end of the extension is generally circular in cross-section along a plane defined by the direction of extension and the longitudinal direction, the cross-section may take other shapes, including other shapes having smooth outer edges, such as oval, etc.

Returning to fig. 1, the ends 1022 of the left three extended portions are connected to positive terminals (not shown) of first, second, and third batteries (not shown), respectively, and the ends 1022 of the right three extended portions are connected to negative terminals (not shown) of fourth, fifth, and sixth batteries (not shown), respectively. As such, the first battery, the second battery, and the third battery are connected in parallel, the fourth battery, the fifth battery, and the sixth battery are connected in parallel, and the combination of the first battery, the second battery, and the third battery is connected in series with the combination of the fourth battery, the fifth battery, and the sixth battery. The connection region of the body region between the series-connected batteries may be referred to as a series connection region, and the connection region of the body region between the parallel-connected batteries may be referred to as a parallel connection region. The body region 101 includes four parallel connection regions 104 and a series connection region 105 between the first cell and the second cell, between the second cell and the third cell, between the fourth cell and the fifth cell, and between the fifth cell and the sixth cell. Each of the parallel connection region 104 and the series connection region 105 is located on the main body region 101 between adjacent extensions 102. The end of the extension may be connected to the positive or negative terminal of the battery in a variety of possible ways including, for example and without limitation, welding, mechanical locking, use of conductive elements, and the like.

For the busbar according to the invention, the main body region thereof may comprise any number of parallel connection regions for parallel connection and/or series connection regions for series connection, for example may comprise only parallel connection regions or only series connection regions. For example, the number of parallel connection regions and/or series connection regions to be included in the main body region and the position in the main body region may be determined according to the number of batteries to be connected to the bus bar and a desired connection manner of the batteries.

Each of the parallel connection regions and/or the series connection regions may optionally be provided as a bilayer region. By providing a double layer region, the current density of the respective connection region can be reduced. The bilayer region may also be referred to as a bilayer material region. The bilayer regions can be formed in various suitable ways. For example, the bus bar material (e.g., aluminum or copper) in the connection region where the double layer region is to be formed may be folded (e.g., flipped) to thereby form the double layer region; alternatively, additional layers are added to the bus bar material by soldering or heat pressing, thereby forming a double layer region. The additional layer may be formed of another material having a lower resistance than the busbar material or the same material as the busbar material. In addition, providing such a double-layered region also facilitates reducing temperature variations of the respective connection regions to reduce temperature differences between the bus bars and the cells connected thereto.

In the body region of a single busbar, for each of the parallel connection regions and/or the series connection regions, it may be arranged identically or differently from the other connection regions, depending on its position in the body region, the magnitude of the current it is intended to withstand, etc. For example, the bilayer regions corresponding to the series connection regions and the bilayer regions corresponding to the parallel connection regions may be provided with different materials, sizes and/or thicknesses. In this way, it is advantageous to save cost and space while meeting the battery connection requirements, or to meet different current density requirements in different regions of the busbar. For example, it is possible that the series connection region is subjected to a greater current density relative to the parallel connection region; in this case, the double-layer region corresponding to the series-connection region may be set to have a larger size or thickness to reduce the current density thereof.

As can be appreciated, the main body region of the bus bar of the present invention has two ends in its longitudinal direction. Each of the two ends may have a chamfered portion formed by cutting off one corner portion therefrom. The cut-out corner may be of various possible shapes, such as triangular, star-shaped, square, rectangular, irregular, etc. The chamfered portions may be located at upper and/or lower portions of the respective ends. The provision of such chamfered portions is advantageous in reducing the transfer of heat. In particular, when a thermal runaway occurs in a certain battery connected by a bus bar, providing such chamfered portions can reduce heat transfer from the battery in which the thermal runaway occurs to other batteries, which is extremely advantageous. In addition, the chamfered portions are beneficial to reducing the weight of the bus bar, and saving materials and cost.

As shown in fig. 1, the main body region 101 has, at upper portions of left and right side ends thereof, corner cuts 103 formed by cutting off triangular corners.

According to the invention, at least one thermal sensor can be arranged on the main body region of the busbar. The at least one thermal sensor may be configured to detect a temperature of a battery to which the bus bar is connected, such as a surface temperature or an internal temperature of the battery. Depending on the circumstances, the thermal sensor may be disposed at or near the end of the body region, or at other locations of the body region or other locations of the bus bar. In the case where one end of the main body region has a chamfered portion, the thermal sensor located at or near the end may be provided in an uncut portion of the end, particularly in or near an edge region of the uncut portion on the side away from the extension portion. For example, in the case of fig. 1, the thermal sensor may be disposed at or near the upper edge of the left-side end of the main body region 101 (i.e., the side away from the extension). In the case where one end of the main body region does not have a chamfered portion, a thermal sensor located at or near the end may be provided in or near a corner region of the end, particularly in or near a corner region of the end on the side away from the extension portion. For example, in the case where the main body region of the bus bar has a rectangular shape, as in the case where the main body region of fig. 1 is not formed with the chamfered portion, the upper corner region of the left end of the main body region is a corner region where the upper edge and the left edge of the rectangle intersect, and the upper corner region of the right end of the main body region is a corner region where the upper edge and the right edge of the rectangle intersect. In the state where the battery is in operation, the current density is low at the end of the bus bar body region, the end has a temperature similar to the body or surface of the battery, and this temperature is close to the internal temperature of the battery, such as the core temperature. It is to be understood that the body region of the busbar of the present invention may have various suitable regular or irregular shapes, such as, but not limited to, rectangular, triangular, square, pentagonal, hexagonal, etc., as appropriate.

Any number of thermal sensors may be provided on a single bus. Each thermal sensor may be arranged to measure the temperature of one or more associated batteries. The position of each thermal sensor may be determined according to the extension corresponding to the battery associated therewith, for example, determined to be close to the middle of the extensions in the longitudinal direction of the main body region and as far away from the extensions as possible in the extension direction of the extensions. For example, in the case of only one thermal sensor, the temperature detected by the one thermal sensor is the measured temperature; in the case where there are a plurality of thermal sensors, an average value, a maximum value, or a minimum value of the temperatures detected by the plurality of thermal sensors may be taken as the measured temperature.

The bus bar of the present invention may be used to connect a plurality of batteries to form a battery system, for example, a battery system for a vehicle. According to circumstances, a plurality of batteries may be connected in parallel and/or in series by one or more bus bars, and one of the positive and negative terminals of each of the plurality of batteries may be connected to an end of a corresponding extension of the used bus bar or one of the plurality of bus bars. In the case where the battery system includes a plurality of bus bars, the respective bus bars may be appropriately electrically connected as necessary.

Herein, the term "battery" may also be referred to as a "unit cell" or a "cell".

Aspects of the present invention may be used in electric vehicles or hybrid vehicles, for example, to form 48V battery systems, hybrid vehicle battery systems, plug-in hybrid vehicle battery systems, electric vehicle battery systems, and the like.

The respective technical features described above may be arbitrarily combined. Although not all possible combinations of features are described, any combination of features should be considered to be covered by the present specification as long as there is no contradiction between such combinations.

While the present invention has been described in connection with the embodiments, it is to be understood by those skilled in the art that the foregoing description and drawings are merely illustrative and not restrictive of the broad invention, and that this invention not be limited to the disclosed embodiments. Various modifications and variations are possible without departing from the spirit of the invention.

Claims

1. A buss bar for a battery comprising:

a body region; and

2. The busbar of claim 1, wherein a cross-section of the first portion in the longitudinal direction is a first shape having smooth outer edges, and a cross-section of the second portion in the longitudinal direction is a second shape having smooth outer edges, the first shape being the same as or different from the second shape.

3. The busbar of claim 1, wherein a cross-section of the first portion along a plane defined by the extending direction and the longitudinal direction is trapezoidal, and a cross-section of the second portion along a plane defined by the extending direction and the longitudinal direction is trapezoidal.

4. The buss bar of claim 1, wherein, for each of the plurality of extensions: the connecting part further comprises a third part between the second part and the first part, wherein the cross section of the third part along the plane defined by the extending direction and the longitudinal direction is square, and the cross section of the third part in the longitudinal direction is constant in size along the extending direction.

5. The buss bar of claim 1, wherein, for each of the plurality of extensions: the cross section of its end in the longitudinal direction has a third shape with a smooth outer edge and is first gradually increasing and then gradually decreasing in the direction of extension.

6. The busbar of claim 2 or 5, wherein the shape is oval or circular.

7. The busbar of any of claims 1-5, wherein the main body region defines a major plane, the extension lying in the major plane or in a plane parallel to the major plane.

8. The buss bar of any of claims 1-5, wherein the body region comprises a double layer region between adjacent extensions.

9. The busbar of any of claims 1-5, wherein the main body region has two ends in the longitudinal direction, at least one of the two ends having a chamfered portion formed by cutting one corner portion therefrom.

10. A battery system comprising a plurality of batteries and the bus bar according to any one of claims 1 to 9, the plurality of batteries being connected in parallel and/or in series by the bus bar, one of a positive terminal and a negative terminal of each of the plurality of batteries being connected to an end of a corresponding one of the extensions of the bus bar.

11. A vehicle comprising the battery system of claim 10.