Inter-cell tab for connecting circular battery cells of a battery
By designing connecting pieces between battery cells and utilizing the hollowed-out areas of the contact base and contact piece to connect with conductive strips, the mechanical stress problem caused by the difference in thermal expansion coefficients of battery cells is solved, and a reliable electrical connection between battery cells is achieved, which is suitable for high-capacity battery systems for electric vehicles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LISA DRAXLMAIER GMBH
- Filing Date
- 2022-09-20
- Publication Date
- 2026-07-07
Smart Images
Figure CN115842219B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a battery cell connecting piece for connecting circular battery cells. Background Technology
[0002] In electric vehicles, the energy to drive the vehicle is derived from batteries. Batteries typically consist of several individual cells connected in series and parallel. As the vehicle operates, energy is drawn from the batteries, causing them to discharge. The individual cells are electrically connected to each other to form a battery cell group. These electrical contact elements are made of bronze alloy and each includes a contact base welded to the positive terminal of the battery cell. Each contact element also includes a contact piece that connects to the contact base and contacts the negative terminal of another battery cell. This creates an electrical contact between the two battery cells. The battery cells are housed in a battery casing, typically made of plastic.
[0003] Because plastic has a significantly higher coefficient of thermal expansion than bronze alloys used in electrical contact elements, uneven expansion or contraction of the electrical contact elements occurs when there is thermal stress during the electrical load of the battery cell or during battery cooling. This uneven expansion or contraction leads to mechanical stress in the electrical contact elements, and consequently, mechanical stress at the weld joint between the positive electrode of the battery cell and the contact base of the electrical contact element. Summary of the Invention
[0004] Therefore, the objective of this invention is to provide a reliable electrical connection of a number of circular battery cells using the simplest possible means.
[0005] This task is accomplished through the subject matter of the independent claims. Advantageous improvements of the invention are described in the dependent claims, the specification, and the drawings.
[0006] One aspect of the invention relates to a cell-to-cell connector for connecting circular battery cells, comprising a plurality of electrical contact elements, each configured to electrically connect a first circular battery cell to a second circular battery cell. Each electrical contact element has a contact base, wherein the electrical contact element and the contact base are respectively connected by material bonding at the positive terminal of the first circular battery cell, each electrical contact element includes a plurality of contact tabs, the electrical contact element being respectively in contact with the negative terminal of the second circular battery cell via the contact tabs, one electrical contact element being connected to another electrical contact element via a conductive link, wherein the material of the electrical contact element is hollowed out in a region between the conductive link and at least one contact tab adjacent to the conductive link, the hollowed-out region being adjacent to the contact base.
[0007] The battery cell interconnection tab includes multiple electrical contact elements. These contact elements are made of conductive material. Each contact element is configured to electrically connect a first circular battery cell to a second circular battery cell at one end. Another contact element of the battery cell interconnection tab is configured to electrically connect a third circular battery cell to a fourth circular battery cell at one end. The contact elements can be connected in series via conductive strips. The circular battery cells can be mounted in a battery casing. The circular battery cells can also be electrically connected to form battery modules. These battery modules are then electrically connected to form a common battery. The battery is for electric drive of a motor vehicle. Within the meaning of this invention, "motor vehicle" refers to both pure electric motor vehicles and hybrid vehicles.
[0008] The contact base of the electrical contact element can be connected to the positive electrode of the first circular battery cell by means of material bonding. For example, the contact base can be soldered to the positive electrode. In the case of the first circular battery cell, the positive electrode can be the battery cap of the circular battery cell. The electrical contact element also includes a plurality of contact tabs. The contact tabs are disposed on and connected to the contact base. With the aid of the contact tabs, the electrical contact element can make electrical contact with the second circular battery cell in such a way that the contact tabs contact the negative electrode of the second circular battery cell. In the case of the second circular battery cell, the negative electrode can be the circumferential surface of the circular battery cell. Here, the contact tabs can be in close contact with the circumferential surface of the second circular battery cell. The second circular battery cell can be inserted into the middle of the contact tabs with its circumferential surface, thereby holding the second circular battery cell in the middle of the contact tabs in a force-transmitting engagement manner.
[0009] For example, the contact base can be designed to protrude, that is, the contact base protrudes in the opposite direction to the extension of the contact piece. This allows the electrical contact element to be connected to the positive terminal of a circular battery cell very simply by means of material bonding.
[0010] The material of the electrical contact element is hollowed out in the area between the conductive strip and at least one contact piece of the electrical contact element adjacent to the conductive strip. The hollowed-out area is immediately adjacent to the contact base of the electrical contact element.
[0011] When a circular battery cell moves within the battery, forces act on the welded joints of the contact base and the contact plates of the electrical contact element, thus subjecting the contact base and contact plates to mechanical stress. The hollowed-out area makes the conductive links between the battery cells elastic, allowing them to compensate for the movement of the circular battery cells. For example, the conductive links can be slightly compressed or stretched, thus compensating for the movement of the circular battery cells. This minimizes mechanical load and ensures reliable electrical contact between the circular battery cells.
[0012] In one embodiment, the connecting strip includes an elastic region configured to absorb mechanical loads. For example, this elastic region may be compressed or stretched during the movement of a circular battery cell, allowing the connecting strip between the battery cells to compensate for the movement of the circular battery cell.
[0013] In one embodiment, the connecting bar includes an inclined surface relative to the contact base in the region where the material has been hollowed out. This facilitates the transfer of only reduced mechanical loads to the contact base during the movement of the circular battery cell. The contact base can also thus be easily connected to the positive electrode of the circular battery cell via a material bonding method.
[0014] In one embodiment, the electrical contact elements are arranged in multiple rows and columns relative to each other, and adjacent electrical contact elements are connected to each other by one of the corresponding connecting bars. Especially for electric vehicles, high capacity is desired. For this purpose, the battery requires many interconnected circular battery cells. Thus, a large number of circular battery cells can be electrically connected in series and parallel, thereby providing a battery with very high capacity.
[0015] In one embodiment, the contact piece is designed to be elastic. This allows the contact piece to optimally conform to the circumferential surface of the second circular battery cell. For example, a spring force can be applied to the contact piece. If thermal stress relaxation is extremely high, the contact piece will lose its clamping force against the circumferential surface of the second battery cell over time. For example, the material of the electrical contact element can deform in the contact piece region, increasing the spring force in the contact piece region, thus ensuring continuous electrical contact between the contact piece and the negative electrode of the second battery cell.
[0016] In one embodiment, each contact piece has a curved surface, thereby allowing the contact piece to be attached to the negative electrode of the second circular battery cell in a surface contact manner.
[0017] In one embodiment, a voltage tap is disposed on at least one electrical contact element, configured to measure the voltage of a first circular battery cell and a second circular battery cell. The voltage tap is used for balancing the circular battery cells during battery operation. During balancing, the voltage of each circular battery cell or each parallel battery pack is monitored. The voltage tap can be, for example, disposed on an electrical contact element of a peripheral device connecting the battery cells and can be designed, for example, as a contact piece. Therefore, instead of monitoring each individual circular battery cell of the battery module separately, the connected circular battery cells of the battery module are monitored mutually via the voltage tap.
[0018] In one embodiment, the inter-cell connecting piece is made of at least one stamped and bent piece.
[0019] The common stamped and bent parts for manufacturing electrical contact elements and conductive links are preferably stamped and formed from a material with good electrical conductivity to obtain the shape of these electrical contact elements. The material of the stamped and bent parts is preferably selected such that it not only meets the requirements for good conductivity, but also the requirements for mechanical properties, especially the requirements for high tensile strength and low thermal stress relaxation.
[0020] For example, a stamped and bent part can be made of a first metal sheet and a second metal sheet, which are connected to each other by overlapping. The first metal sheet can have better electrical conductivity than the second metal sheet. The second metal sheet can have higher elastic stiffness than the first metal sheet. Attached Figure Description
[0021] Advantageous embodiments of the invention will now be explained with reference to the accompanying drawings, in which:
[0022] Figure 1 A top view of the inter-cell connection piece of the first embodiment is shown.
[0023] Figure 2 A perspective view of the inter-cell connection piece of the first embodiment is shown.
[0024] Figure 3 A side view of the battery cell interconnection tabs of the second embodiment is shown. Detailed Implementation
[0025] The figures are merely illustrative and are used only to explain the invention. Identical or functionally equivalent parts are always marked with the same reference numerals.
[0026] Figure 1 This is a top view of the battery cell connecting piece 110 according to the first embodiment. The battery cell connecting piece 110 includes a first electrical contact element 100a and a second electrical contact element 100b. The first electrical contact element 100a and the second electrical contact element 100b are connected to each other by a connecting strip 102. In the first embodiment, the battery cell connecting piece 100 is made by stamping and bending. In another embodiment, the battery cell connecting piece may be composed of individual components, for example, welded to each other. The first contact element 100a and the second contact element 100b are used to electrically connect a first circular battery cell to a second circular battery cell, respectively. The first electrical contact element 100a and the second electrical contact element 100b each include contact bases 103a and 103b.
[0027] First electrical contact element 100a and second electrical contact element 100b are respectively welded to the positive electrode of the first circular battery cell on their respective contact bases 103a and 103b, that is, the respective contact bases 103a and 103b are connected to the positive electrode of the respective first circular battery cell by material bonding. First electrical contact element 100a and second electrical contact element 100b also include contact pieces 101a and 101b. The contact pieces are used to contact the respective negative electrode of the respective second circular battery cell. In the case of a circular battery cell, the negative electrode is formed on the circumferential surface of the circular battery cell. In the first embodiment, the contact pieces 101a and 101b are elastically formed. Furthermore, the ends of the contact pieces 101a and 101b are bent outwards, thereby simplifying the insertion of the negative electrode of the second circular battery cell centrally within these contact pieces 101a and 101b.
[0028] From Figure 1 As seen in the image, the material of contact elements 100a and 100b is hollowed out in the area between the connecting strip 102 and their respective adjacent contact pieces 101a and 101b. The hollowed-out material area 104 provides greater flexibility for the connecting piece 110 between battery cells, and may therefore compensate for the movement of the circular battery cell on all spatial axes.
[0029] Figure 2 A perspective view of the cell-to-cell connecting strip 110 of the first embodiment is shown. The connecting strip 102 is designed to protrude relative to the contact bases 103a and 103b. This allows the first circular cell cells, which are respectively connected to the contact bases 103a and 103b by material bonding, to be arranged side-by-side in a row-and-column configuration to save space. The connecting strip 102 of the cell-to-cell connecting strip 110 includes a bevel 106 in the contact base 103a and 103b regions. The bevel 106 facilitates mechanical isolation of the connecting strip 102.
[0030] A battery comprises numerous components made of vastly different materials. Due to varying coefficients of thermal expansion, these components can expand or contract differently under the battery's thermal load, thus altering their shape. This component movement can cause the connecting tabs between battery cells to experience unacceptable mechanical loads. The inclined plane 106 mechanically isolates the contact bases 103a, 103b from the connecting bar 102, so that forces acting on the connecting bar 102 are not transmitted to the contact bases 103a, 103b in the same manner.
[0031] Figure 3A side view of the battery cell connecting tabs of the second embodiment is shown. The positive electrode 109 of the first circular battery cell 107 is soldered to the contact base 103a of the first electrical contact element 100a. The positive electrode 110 of the second circular battery cell 108 is soldered to the contact base 103b of the second electrical contact element 100b. Other circular battery cells can be centrally inserted into the first and second electrical contact elements 100a and 100b within these contact tabs 101a and 101b. The contact tabs 101a and 101b then surround the circumference of the other circular battery cells to fix the circular battery cells to their respective electrical contact elements 100a and 100b, and the contact tabs 101a and 101b simultaneously contact the negative electrode of the circular battery cell.
[0032] List of reference numerals
[0033] 100a,b contact elements
[0034] 101a,b contact pieces
[0035] 102 consecutive lines
[0036] 103a,b Contact base
[0037] 104 Hollowed-out area
[0038] 106 bevel
[0039] 107 First circular battery cell
[0040] 108 Second circular battery cell
[0041] 109 Positive electrode of the first circular battery cell
[0042] 110 Positive electrode of the second circular battery cell
Claims
1. A battery-to-battery connector (110) for connecting a circular battery, comprising a plurality of electrical contact elements (100a, b), each electrical contact element being configured to electrically connect a first circular battery (107) to a second circular battery, and each of the electrical contact elements (100a, b) having a contact base (103a, b), wherein, The electrical contact elements (100a,b) with the contact bases (103a,b) can be material-bonded to the positive terminal (109) of the first circular battery (107), and The electrical contact elements (100a, b) each include a plurality of contact pieces (101a, b), and the electrical contact elements (100a, b) can respectively contact the negative terminal of the second circular battery through the contact pieces, and The corresponding electrical contact elements (100a, b) are connected to the corresponding other electrical contact element (100a, b) via conductive links (102). In this process, the material of the electrical contact element (100a,b) is hollowed out in the region between the conductive link (102) and at least one contact piece (101a,b) adjacent to the conductive link (102), and the hollowed-out region (104) is adjacent to the contact base (103a,b). The connecting bar (102) includes an elastic region for absorbing mechanical loads, and the connecting bar (102) includes a slope (106) relative to the contact base in the region (104) of the hollowed-out material.
2. The battery interconnector (110) according to claim 1, wherein, These electrical contact elements (100a,b) are arranged relative to each other in a plurality of rows and columns, and the corresponding directly adjacent electrical contact elements (100a,b) are interconnected by means of one of the connecting strips (102).
3. The battery interconnector according to claim 1, wherein, The contact pieces (101a,b) are elastically formed.
4. The battery interconnector (110) according to any one of claims 1 to 3, wherein, The contact pieces (101a, b) each include a curved surface, thereby allowing the contact pieces (101a, b) to be in surface contact with the negative terminal of the second circular battery.
5. The battery interconnector (110) according to any one of claims 1 to 3, wherein, A voltage tap is arranged on at least one of the electrical contact elements (100a,b), the voltage tap being configured to measure the voltage of the first circular battery (107) and the second circular battery.
6. The battery interconnector (110) according to any one of claims 1 to 3, wherein, The battery interconnector (110) is made of at least one stamped and bent part.