This invention relates to a battery pack.
With the popularization of environmental consciousness, the electric vehicle or hybrid vehicle shall substitute the existing fuel-combustion vehicle in future. As the core power source of electric vehicle, the power battery pack is especially important, which may be formed by a plurality of cells connected in series or in parallel.
CN 1767245A discloses a battery module. As shown in
In the battery module as mentioned above, the positive terminal and the negative terminal are connected threadly and fixed by the fixing member, thus its contact resistance is high; if the thread connection looses, the contact resistance will be higher. Thus, the internal resistance of this battery module is very high; moreover, because each unit cell requires the positive and negative terminals with male threads as the conducting element, and the connecting member and the fixing member for connecting multiple unit cells in series, thus, the weight and volume of the battery module are increased.
This invention aims to provide a battery pack which has a low internal resistance.
This invention provides a battery pack, which comprises a plurality of unit cells each of which has two electrode terminals, and which are connected in series or in parallel by connecting an electrode terminal of a unit cell to an electrode terminal of an adjacent unit cell, wherein the electrode terminals each is formed in a sheet shape, and the connection between the electrode terminals is the binding of two sheets.
For the battery pack in this invention, the electrode terminals of the unit cell, i.e., the positive terminal and the negative terminal are formed in a sheet shape, so that multiple unit cells can be connected electrically together through binding the sheet shape electrode terminals of adjacent two unit cells, with almost no contact resistance between unit cells, and the electrode terminals bound together will not loose. Thus, as compared with the prior battery pack in which the unit cells are screwed together, the battery pack in the present invention has low internal resistance, light weight, and reliable connection.
Moreover, the battery pack adopts the sheet as the electrode terminal which can be directly bound together, so it is not necessary to use additional connecting members and, as a result, the weight and volume of the battery pack may be greatly reduced.
Hereinafter, the present invention will be described in detail with reference to the drawings.
As shown in
In the present invention, the unit cell may be any suitable type in the prior art, such as the prismatic cell or cylindrical cell. Multiple unit cells may be connected in series or in parallel to form the battery pack.
As shown in
Within the unit cell, the positive and negative terminals may be directly connected with the positive and negative plates, for example, the positive terminal may be welded with the positive plate, and the negative terminal may be welded with the negative plate. Preferably, the positive plate 5 has a positive tab 10 which is connected with the positive terminal 2; the negative plate 6 has a negative tab 11 which is connected with the negative terminal 3.
The positive and negative tabs may be made of various conductive materials, which may be preferably one or more of copper, nickel and aluminum. Preferably, the electrode terminal is connected with the electrode tab and the electrode tab is connected with the electrode plate by means of welding, such as ultrasonic welding, cold pressure welding, laser welding, brazing, flash butt welding, friction welding, and electric resistance welding.
The welding position between the negative tab 11 and the negative terminal 3, as well as between the positive tab 10 and the positive terminal 2 may be provided with an insulating ring 12 respectively. The insulating ring 12 is formed as two segments, during assembly, the insulating ring may be enclosed around the welding position for insulating and shock absorbing to improve the safety of the cell. The insulating ring may be made of various insulation materials such as plastics and rubbers.
After multiple unit cells are connected together to form the battery pack, the battery pack may be fixed by means of various methods in the prior art, such as arrangement of heat-sinking structure between adjacent unit cells, and fasten the connected unit cells together to avoid the displacement of the unit cells.
In the present invention, in order to install the sheet shape electrode terminal and assemble the battery pack easily, the unit cell is preferably the prismatic cell. The width of the sheet shape electrode terminal may be 5-40% of the width of the unit cell, 10-25% is preferred; the thickness of the sheet shape electrode terminal may be 1-20% of the unit cell thickness, 3-15% is preferred.
As shown in
In the present invention, the electrode terminal is formed in a sheet shape, and the electrode terminals are connected through the binding of the sheets. The binding of the sheets may be further fixed by means of various manners, such as welding, gluing or a clamp, or any combinations thereof, for example, a clamp may further used after the welding or gluing. In a preferred embodiment as shown in
In the present invention, two sheet shape electrode terminals are preferably fixed by welding, such as the cold pressure welding, ultrasonic welding, laser welding, brazing, flash butt welding, friction welding, and electric resistance welding, wherein the cold pressure welding is preferred. For cold pressure welding, only the adequate static pressure may realize the reliable weld, and during the weld process, the heat emission is low, no vibration and no relative displacement will be occurred.
In an embodiment as shown in
The rivet 8, the insulating elastic component 9 and the electrode terminal may be integrated by injection molding. That is, the rivet 8, the insulating elastic component 9 and the electrode terminal may be integrated together through injection molding, and then match the integral structure with the through hole on the cover plate. And then, as shown in FIG. 6, the rivet is tightly clamped to seal the electrode terminal. In this preferred embodiment, the sealing can be realized easily and reliably.
In addition, in a preferred embodiment as indicated by the broken line in
As it may be seen from the above description, in the battery pack according to the present invention, the electrode terminal of the unit cell, i.e., the positive terminal and the negative terminal are formed in a sheet shape, through binding of the sheet shape electrode terminals of adjacent two unit cells, the electrical connection of multiple unit cells can be realized, and almost no contact resistance will be occurred between the unit cells, moreover, after welding, no loose problems of electrode terminals will be occur. Thus, as compared with the prior battery pack with screwed unit cells, the battery pack in the present invention has lower internal resistance.
Moreover, the present battery pack adopts the sheet shape electrode terminal which can be directly welded, no additional connecting member is necessary, thus, the weight and volume of the battery pack may be greatly reduced.
Number | Date | Country | Kind |
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200710103771.3 | May 2007 | CN | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CN2007/071348 | 12/27/2007 | WO | 00 | 7/14/2009 |