Battery cell assembly with a battery cell having an integrated busbar

Abstract

Battery cell assembly (100) comprising: a first battery cell (102) having a first terminal (108), a second terminal (110) and a main body (106) with an active material designed to generate power from an electrochemical reaction; and a second battery cell (104) having a first terminal (108), a second terminal (110) extending from the second battery cell (104) in a single direction, and a main body (106) with an active material designed to generate power from an electrochemical reaction, wherein the first battery cell (102) is arranged adjacent to the second battery cell (104);wherein the first terminal (108) of the first battery cell (102) comprises an integrated busbar (112), the integrated busbar (112) comprising: a first planar section (118) extending from the first terminal (108) of the first battery cell (102) in a first direction; and a second planar section (120) extending in a second direction towards the second terminal (110) of the second battery cell (104), the second direction being different from the first direction, and wherein the second planar section (120) is in contact with the second terminal (110) of the second battery cell (104) on one side of the second planar section (120);wherein at least a part of the first terminal (108) of the first battery cell (102), at least a part of the first planar section (118) of the integrated busbar (112) and at least a part of the second planar section (120) of the integrated busbar (112) are formed in one piece.

Description

FIELD OF THE INVENTIONThe present disclosure relates to a battery pack, and more particularly, to an integrated bus bar for the battery pack.BACKGROUND OF THE INVENTIONA battery cell has been proposed as a clean, efficient, and environmentally responsible energy source for electric vehicles and various other applications. One type of battery cell is known as a lithium ion battery. The lithium ion battery is rechargeable and can be formed into a variety of shapes and sizes to efficiently fill space available in electric vehicles. The battery cell may be in the form of a prismatic can, for example.In a battery pack, multiple battery cells may be provided to provide an amount of power sufficient to operate electric vehicles. Typically, the plurality of battery cells are interconnected by a separate elongate bus bar. The separate bus bar often has multiple holes that receive bolts from the battery cells. The bolts are often threaded and nut-connected to the bus bar or welded directly to the bus bar. The many different electrical interfaces along the busbar may result in power losses due to an electrical resistance at the individual connections. The large number of electrical interfaces along the bus bar also increases a likelihood of undesirable battery pack behavior and contributes to a manufacturing complexity of the known battery pack.US 2009 / 0 208 836 A1 discloses a battery having two terminals, both of which are L-shaped and extend beyond the periphery of the battery, wherein the horizontal sections of the first terminal and of the second terminal have different lengths, so that the first terminal of one battery rests on the second terminal of an adjacent battery. In addition, a three-part housing for a battery cell comprises a round cover which has a pin-shaped connection insulated from the cover in the middle. At the edge of the cover, a flange is formed which extends outwards from the cover and functions as a busbar. Further prior art is known from DE 10 2006 015 566 A1.SUMMARY OF THE INVENTIONIt is an object of the invention to provide a battery cell assembly that enables electrical connection of battery cells with a minimum number of components, minimizes an electrical resistance in the battery cell assembly, minimizes the mass of the battery cell assembly, minimizes a potential for undesirable behavior, and minimizes the manufacturing complexity of the battery cell assembly.To achieve the object, a battery cell assembly having the features of claim 1 is provided. Advantageous embodiments of the invention can be taken from the dependent claims, the description and the drawings.The battery cell assembly of the present invention includes a first battery cell having a first terminal, a second terminal, and a main body with an active material configured to generate power from an electrochemical reaction, and a second battery cell having a first terminal, a second terminal extending from the second battery cell in a single direction, and a main body with an active material configured to generate power from an electrochemical reaction, wherein the first battery cell is disposed adjacent to the second battery cell. The first terminal of the first battery cell includes an integrated bus bar. The integrated bus bar includes a first planar portion extending from the first terminal of the first battery cell in a first direction and a second planar portion extending in a second direction toward the second terminal of the second battery cell, wherein the second direction is different from the first direction, and wherein the second planar portion is in contact with the second terminal of the second battery cell on a side of the second planar portion. At least a portion of the first terminal of the first battery cell, at least a portion of the first planar portion of the integrated busbar, and at least a portion of the second planar portion of the integrated busbar are integrally formed.In another embodiment, a battery cell assembly includes a first battery cell having a main body with an active material configured to generate power from an electrochemical reaction and a first terminal with an integrated bus bar. The integrated bus bar is substantially L-shaped and includes a first portion extending outward from the main body. The integrated bus bar also includes a second portion connected to the first portion. The second portion extends laterally from the first portion. The battery cell assembly also includes a second battery cell disposed adjacent to the first battery cell. The second battery cell has a main body comprising active material configured to generate power from an electrochemical reaction. The second battery cell also includes a second terminal in electrical communication with the second portion of the integrated bus bar of the first battery cell.DRAWINGSThe foregoing as well as other advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, particularly when considered in view of the drawings described herein. FIG. 1 is a perspective view of a battery pack according to an embodiment of the present disclosure, wherein two battery cells are shown in electrical communication; FIG. 2 is an enlarged fragmentary perspective view of the battery pack shown in circle 2 of FIG. 1, further illustrating a tab of an integrated bus bar of one of the battery cells; FIG. 3 is a perspective view of a battery pack according to another embodiment of the present disclosure, wherein two battery cells are shown in electrical communication; and FIGS. 4A-4E are enlarged fragmentary cross-sectional views of the battery pack taken along section line 4 of FIG. 1, further illustrating various embodiments of the integrated bus bar of the one of the battery cells, where FIGS. 4A-4C show embodiments of the invention and FIGS. 4D and 4E show embodiments not of the invention.DETAILED DESCRIPTION OF THE INVENTIONThe following detailed description and the accompanying drawings describe and illustrate various embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any way.Referring to FIGS. 1-2, a battery cell assembly 100 according to an embodiment of the present disclosure is shown. The battery cell assembly 100 includes a plurality of battery cells 102, 104. The battery cells 102, 104 shown are battery cells with a prismatic can or a cuboidal sheet metal container. As a non-limiting example, the battery cells 102, 104 may be a prismatic-can lithium-ion (Li-ion) battery cell. It should be appreciated that other can-type battery cells 102, 104 utilizing a different structure, such as cylindrical, and a different electrochemistry may also be used within the scope of the present invention. Although only two battery cells 102, 104 are shown in FIG. 1, it should be appreciated that additional similar battery cells 102, 104 may be arranged in an array to form the battery pack assembly 100 of the present disclosure.The battery cell assembly 100 of the present disclosure includes a first battery cell 102 and a second battery cell 104. The first battery cell 102 is arranged adjacent to the second battery cell 104, for example in an arrangement of the battery cells 102, 104. Each of the first battery cell 102 and the second battery cell 104 includes a main body 106 having an active material configured to generate power from an electrochemical reaction. The first battery cell 102 and the second battery cell 104 each also include a first terminal 108 and a second terminal 110. The first terminal 108 may be positive and the second terminal 110 may be negative or vice versa as needed.When the first terminal 108 is used in a positive case battery system, for example as illustrated in FIGS. 1-4E, the first terminal 108 may be in electrical communication with the main body 106. However, one skilled in the art should understand that the present invention is also applicable to a neutral reservoir battery system wherein the first terminal 108 is electrically insulated from the main body 106, for example, with a polymer spacer or the like. One of ordinary skill in the art should therefore appreciate that the present invention may be independent of use whether the battery system includes a positive or a neutral reservoir as desired.The first terminal 108 includes an integrated bus bar 112. The integrated bus bar 112 is configured to place the first terminal 108 of the first battery cell 102 in electrical communication with the second terminal 110 of the adjacent second battery cell 104. In particular, the integrated bus bar 112 of the first terminal 108 of the first battery cell 102 is connected to the second terminal 110 of the second battery cell 104. The integrated bus bar 112 may be welded to the second terminal 110, for example, by laser welding or the like.In a particular embodiment illustrated in FIG. 3, the integrated bus bar 112 has an opening 114 formed therein, and the second terminal 110 includes an electrical pin 116 received in the opening 114 of the integrated bus bar 112. The electrical pin 116 may be threaded and allow mechanical attachment of the integrated busbar 112 to the second terminal 110 with a threaded nut 117. Other means for attaching the integrated bus bar 112 of the first terminal 110 of the first battery cell 102 to the second terminal 110 of the second battery cell 104 may also be used within the scope of the present disclosure.Referring now to FIGS. 4A-4E, the integrated bus bar 112 of the present disclosure includes a first portion 118 and a second portion 120. The first portion 118 extends laterally outward from the main body 106. The second portion 120 is coupled to the first portion 118 and extends laterally from the first portion 118. In certain embodiments, the first portion 118 and the second portion are integrally formed as one piece. The second portion 120 protrudes beyond the main body 106 and contacts the second terminal 110 to put the first battery cell 102 in electrical communication with the second battery cell 104. In a particular embodiment, the integrated bus bar 112 is substantially L-shaped in cross-section. When the integrated busbar 112 has the first portion 118 and the second portion 120 and the integrated busbar 112 includes the opening 114 for receiving the electrical pin 116, as shown in FIG. 3, the opening 114 may be formed in the second portion of the integrated busbar 112.Embodiments in which the integrated bus bar 112 is rigid are shown in FIGS. 4A-4B. When the integrated bus bar 112 is rigid, it should be appreciated that the first battery cell 102 and the adjacent second battery cell 104 must be manufactured as different units and alternated throughout the battery pack 100 to ensure connection of the first and second battery cells 102, 104 in series. As a non-limiting example, the rigid integrated bus bar 112 may be formed from a unitary electrically conductive material, as shown in FIG. 4A. As certain non-limiting examples, the rigid, unitary integrated bus bar may be formed of aluminum or copper. One skilled in the art can choose other suitably stiff, electrically conductive materials as desired.Referring to FIG. 4B, the integrated bus bar 112 is rigid and includes a first electrically conductive material 122 and a second electrically conductive material 124. The second electrically conductive material 124 is deposited on the first electrically conductive material 122. By way of non-limiting example, the first electrically conductive material 122 is copper and the second electrically conductive material 124 is nickel, zinc, or tin. When the integrated bus bar 112 is coated, the integrated bus bar 112 may be particularly suitable for resistance welding or mechanical fastening, as illustrated in FIG. 3, for example. The coating of the second electrically conductive material 124 is typically a metal that is more neutral than a metal of the first electrically conductive material 122. The coating of the second electrically conductive material 124 may be provided to reduce galvanic corrosion. It should be appreciated that other electrically conductive materials may be used for the first electrically conductive material 122 and the second electrically conductive material 124, within the scope of the present disclosure.Referring to FIG. 4C, the integrated bus bar is rigid and includes the first electrically conductive material 122 plated to the second electrically conductive material 124. The plating process includes a fixed interface 125 where the first electrically conductive material 122 and the second electrically conductive material 124 are pressed together. The second electrically conductive material 124 is typically selected to be weldable to the material of the second terminal 110. For example, the same or similar materials may be used for both the second electrically conductive material 124 and the material of the second terminal 110 when welding, such as laser welding, is desired. As a non-limiting example, the first electrically conductive material 122 may be formed of aluminum and the second electrically conductive material 124 may be formed of copper. The use of copper plated aluminum for the integrated bus bar 112 may allow a desirable welding operation to connect the integrated bus bar 112 to the second terminal 110, for example, when the second terminal 110 is also formed of copper. It should be appreciated that other electrically conductive materials may be used for the first electrically conductive material 122 and the second electrically conductive material 124, within the scope of the present disclosure.Non-inventive embodiments where the integrated bus bar 112 is flexible are shown in FIGS. 4D-4E. When the integrated bus bar 112 is flexible, it will be appreciated that the first battery cell 102 and the adjacent second battery cell 104 may be manufactured the same and the integrated bus bar 112 is curved or bent in a desired direction when the first battery cell 102 and the second battery cell 104 are arranged in an array in the battery pack 100. For example, the first battery cell 102 may have the integrated bus bar 112 curved or bent in a first direction and the second battery cell 104 may have the integrated bus bar 112 curved or bent in a second direction different from the first direction, wherein subsequent battery cells 102, 104 alternate in the battery pack 100 in a similar manner to assemble the battery pack 100. The flexible integrated bus bar 112 thereby advantageously enables a minimum manufacturing complexity for the battery pack 100 of the present disclosure.As shown in FIG. 4D, the integrated bus bar 112 is flexible and may include a laminate formed from a plurality of electrically conductive layers 126. As an example not according to the invention, the electrically conductive layers 126 may comprise a plurality of thin copper layers. Each of the electrically conductive layers 126 has a thickness that facilitates bending of the laminate formed from the electrically conductive layers 126. By way of non-limiting example, the thickness of each of the electrically conductive layers 126 may be between about 5 mils (0.127 mm) and about 20 mils (0.508 mm). Laminating the thin electrically conductive layers 112 facilitates flexibility and bending of the integrated bus bar 112 during assembly of the battery pack 100. A person skilled in the art can select types of the electrically conductive layers 126 and a suitable thickness of the electrically conductive layers as required.Referring to FIG. 4E, the integrated bus bar 112 is flexible and may include a braided electrically conductive material 128. As an example not according to the invention, the braided electrically conductive material 128 may be a copper braid. Other types of electrically conductive fabrics or webs, including other types of electrically conductive materials, may also be used as the braided electrically conductive material 128.Advantageously, the integrated bus bar 112 of the present disclosure enables assembly of the battery pack 100 with fewer components. A source of electrical resistance and possibly undesirable behavior in prior art battery packs is also eliminated by the use of the integrated bus bars 112 of the first and second battery cells 102, 104, as the integrated bus bars 112 are not separately connected to both the first battery cell 102 and the second battery cell 104. Durability of the battery pack 100 is also optimized by minimizing the number of electrical interfaces in the battery pack 100 by using the integrated bus bars 112.While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be understood by those skilled in the art that various changes may be made therein without departing from the scope of the disclosure, which is further described in the following appended claims.

Claims

A battery cell assembly (100) comprising: a first battery cell (102) having a first terminal (108), a second terminal (110), and a main body (106) having an active material configured to generate power from an electrochemical reaction; and a second battery cell (104) having a first terminal (108), a second terminal (110) extending from the second battery cell (104) in a single direction, and a main body (106) having an active material configured to generate power from an electrochemical reaction, wherein the first battery cell (102) is disposed adjacent to the second battery cell (104); wherein the first terminal (108) of the first battery cell (102) comprises an integrated bus bar (112), wherein the integrated bus bar (112) comprises: a first planar portion (118) extending from the first terminal (108) of the first battery cell (102) in a first direction; and a second planar portion (120) extending in a second direction toward the second terminal (110) of the second battery cell (104), wherein the second direction is different from the first direction, and wherein the second planar portion (120) is in contact with the second terminal (110) of the second battery cell (104) on a side of the second planar portion (120); wherein at least a portion of the first terminal (108) of the first battery cell (102), at least a portion of the first planar portion (118) of the integrated busbar (112), and at least a portion of the second planar portion (120) of the integrated busbar (112) are integrally formed.The battery cell assembly (100) of claim 1, wherein the integrated bus bar (112) is substantially L-shaped.The battery cell assembly (100) of claim 2, wherein the integrated bus bar (112) includes an opening (114) formed in the second portion (120) configured to receive an electrical pin (116) of the second terminal (110) of the second battery cell (104).The battery cell assembly (100) of claim 3, wherein the electrical pin (116) is threaded and configured to be fastened to the integrated busbar (112) with a nut (117).The battery cell assembly (100) of claim 1, wherein the integrated bus bar (112) is rigid and is formed from a unitary electrically conductive material.The battery cell assembly (100) of claim 1, wherein the integrated bus bar (112) is rigid and comprises a first electrically conductive material coated with a second electrically conductive material.The battery cell assembly (100) of claim 1, wherein the integrated bus bar (112) is rigid and comprises a first electrically conductive material plated with a second electrically conductive material.

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