Battery cell

Abstract

A battery cell has a plurality of first electrode tabs and a plurality of second electrode tabs welded to a current collector. The current collector has a first side and a second side. Each electrode plate of a plurality of first electrodes is coupled to the first side surface. In addition, each electrode tab of a plurality of second electrodes is coupled to the second side.

Description

Technical Field

[0001] The present disclosure relates to electrode stacks in battery cells, and more particularly to electrode stacks configured to reduce heat generation and space usage. Background Art

[0002] A rechargeable energy storage system (RESS), such as a prismatic battery cell, typically includes multiple electrode stacks. Each electrode stack includes an anode electrode sheet and a cathode electrode sheet extending from the electrode stack. The electrode sheets of the electrode stack can be connected to multiple current collectors. The current collector is a metal plate that is used to consolidate the current generated by the electrode stack and transmit it to the terminals on the battery cell. However, multiple current collectors take up a large footprint within the battery cell. The electrode stack and the current collector are typically placed in a case or enclosure to protect the electrode stack from the surrounding environment. When current passes through the anode electrode sheet and the cathode electrode sheet, the resistance generates heat. An increase in temperature on one or more electrode stacks due to excessive heat generation may cause the entire RESS temperature to increase, resulting in poor performance or failure of the RESS.

[0003] Although prior art methods and systems attempt to minimize heat generation and space occupied by current collectors and can achieve their specific purposes, there is still a need for new and improved systems for reducing heat generation within an electrode stack while minimizing the space occupied by the current collectors. Therefore, there is a need for a battery cell having an electrode stack and a current collector that is configured to minimize heat generation and space occupied by the current collectors within the battery cell. Summary of the invention

[0004] According to several aspects of the present disclosure, a battery cell having a plurality of first electrode sheets and a plurality of second electrode sheets welded to a current collector is provided. The battery cell includes a plurality of first electrodes, a plurality of second electrodes, and a current collector. Each of the plurality of first electrodes has an electrode sheet, and each of the plurality of second electrodes has an electrode sheet. In addition, the current collector has a first side and a second side, wherein each electrode sheet of the plurality of first electrodes is coupled to the first side, and wherein each electrode sheet of the plurality of second electrodes is coupled to the second side.

[0005] According to another aspect of the present disclosure, a battery cell includes a first side surface having a plurality of surface portions for coupling each electrode sheet of a plurality of first electrodes.

[0006] According to another aspect of the present disclosure, a battery cell includes a second side surface having a single surface portion for coupling each electrode sheet of a plurality of second electrodes.

[0007] According to another aspect of the present disclosure, a battery cell includes a plurality of electrode sheets of the second electrode wrapped on the second side and stacked together.

[0008] According to another aspect of the present disclosure, a battery cell includes an electrode sheet of a plurality of first electrodes divided into groups. Each group is coupled to a first side of a current collector, and the plurality of first electrodes includes between 80% and 90% of the electrodes.

[0009] According to another aspect of the present disclosure, a battery cell includes an electrode tab of a plurality of second electrodes coupled to a second side, the electrode tab being bent in an opposite direction to an electrode tab of a plurality of first electrodes coupled to a first side.

[0010] According to another aspect of the present disclosure, a battery cell includes a first side having a weld surface portion to which electrode tabs of a plurality of first electrodes are coupled.

[0011] According to another aspect of the present disclosure, a battery cell includes a current collector having a thickness between 0.4 mm and 1 mm.

[0012] According to another aspect of the present disclosure, a battery cell includes a first side of a current collector facing toward an electrode stack. A second side of the current collector faces away from the electrode stack.

[0013] According to another aspect of the present disclosure, the battery cell includes a current collector 3 mm from the electrode stack.

[0014] According to another aspect of the present disclosure, a battery cell includes an electrode tab of a plurality of first electrodes coupled to a current collector by a set of parallel welds on a first side. The set of parallel welds includes five to ten welds.

[0015] According to another aspect of the present disclosure, a battery cell has an electrode tab of a plurality of second electrodes coupled to a current collector by a single weld on the second side. The single weld is perpendicular to the set of parallel welds.

[0016] According to another aspect of the present disclosure, a battery cell includes a plurality of first electrode electrode tabs and a plurality of second electrode electrode tabs coupled to a current collector by laser welding.

[0017] According to another aspect of the present disclosure, the battery cell further includes a plurality of electrode sheets of a plurality of third electrodes and a plurality of electrode sheets of a plurality of fourth electrodes extending from a second side of the electrode stack. The battery cell further includes a second current collector having a third surface and a fourth surface. Each electrode sheet of the plurality of third electrodes is coupled to the third side, and each electrode sheet of the plurality of fourth electrodes is coupled to the fourth side.

[0018] According to another aspect of the present disclosure, a battery cell includes a second side of the battery cell opposite to the first side of the battery cell.

[0019] According to one aspect of the present disclosure, a vehicle having a battery pack is provided. The vehicle having the battery pack includes a plurality of first electrodes, a plurality of second electrodes, and a current collector. Each of the plurality of first electrodes has an electrode sheet, and each of the plurality of second electrodes has an electrode sheet. In addition, the current collector has a first side and a second side, wherein each electrode sheet of the plurality of first electrodes is coupled to the first side, and wherein each electrode sheet of the plurality of second electrodes is coupled to the second side.

[0020] According to another aspect of the present disclosure, a vehicle having a battery pack includes electrode sheets of a plurality of first electrodes, the electrode sheets of the first electrodes comprising between 80% and 90% of the electrode sheets, and electrode sheets of a plurality of second electrodes comprising between 10% and 20% of the electrode sheets.

[0021] According to one aspect of the present disclosure, a method for laser welding an electrode sheet to a current collector is provided. The method includes sweeping a plurality of first electrode sheets of a plurality of first electrodes and a plurality of second electrode sheets of a plurality of second electrodes along a first welding direction. In addition, the method includes laser welding a plurality of first electrode sheets to a first side of the current collector. The method also includes bending a plurality of second electrode sheets at the top of the current collector to a second side along a second welding direction. In addition, the method includes laser welding a plurality of second electrode sheets to a second side of the current collector, and the second side is opposite to the first side.

[0022] According to another aspect of the present disclosure, the method includes laser welding a plurality of first electrode tabs to a first side of a current collector, the method further comprising laser welding between 80% and 90% of the first electrode tabs.

[0023] According to another aspect of the present disclosure, the method includes bending the second electrode sheet by 10% to 20%.

[0024] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0025] The above features and advantages and other features and advantages of the presently disclosed systems and methods are apparent from the detailed description, including the claims and exemplary embodiments, when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure can be more fully understood from the detailed description and accompanying drawings, in which:

[0027] Figure 1 is a perspective view showing an example of a transportation vehicle including a battery pack having a plurality of battery cells according to the present disclosure.

[0028] Figure 2A According to the present disclosure, Figure 1 A perspective view of a battery cell within a battery pack is shown, wherein the battery cell includes at least one electrode stack having a plurality of first electrode tabs and a plurality of second electrode tabs laser welded to a current collector.

[0029] Figure 2B is a partial cross-sectional view of the battery cell shown in FIG. 2 showing the layers in a single electrode stack according to the present disclosure.

[0030] Figure 3 2 , a plurality of electrode sheets, and a plurality of current collectors, wherein a plurality of first electrode sheets and a plurality of second electrode sheets extend from a first side of the electrode stack, and a plurality of third electrode sheets and a plurality of fourth electrode sheets extend from a second side of the electrode stack according to the present disclosure.

[0031] Figure 4 2 is a side view of a battery cell shown in FIG. 2 according to the present disclosure, wherein a plurality of first portions of an electrode sheet are welded to a current collector using a set of parallel laser welds, and a plurality of second portions of an electrode sheet are welded to the current collector using a single laser weld perpendicular to the set of parallel laser welds.

[0032] Figure 5 is a flow chart illustrating a method for laser welding an anode electrode sheet and a cathode electrode sheet to a current collector according to the present disclosure. DETAILED DESCRIPTION

[0033] Reference will now be made in detail to several examples of the present disclosure shown in the accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and description to refer to the same or similar parts or steps. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or use.

[0034] refer to Figure 1 , a perspective view of a vehicle 10 having a battery pack 12 according to the present disclosure is shown. The battery pack 12 is shown together with an exemplary vehicle 10. The vehicle 10 is an electric vehicle or a hybrid vehicle having wheels 11 driven by a motor / inverter 13. The motor / inverter 13 receives power from the battery pack 12. Although the vehicle 10 is shown as a passenger road vehicle, it should be understood that the battery pack 12 can be used with various other types of vehicles. For example, the battery pack 12 can be used in a marine vehicle such as a ship or an aviation vehicle such as a drone or a passenger aircraft. In addition, the battery pack 12 can be used as a fixed power source that is separate and independent from the vehicle. The battery pack 12 includes a housing 14 for supporting a plurality of battery cells 18. The battery pack 12 can have fifty or more battery cells 18.

[0035] Reference Figure 2A According to one aspect of the present disclosure, it is shown Figure 1 A perspective view of a battery cell 18 within a battery pack 12 shown. Each battery cell 18 has a housing or shell (not shown) and a plurality of electrode stacks 22. Each battery cell 18 may have hundreds of electrode stacks 22. Each electrode stack 22 is connected to a current collector 24, a current collector 26. In addition, the electrode stack 22 is placed in the housing, and the housing is filled with a suitable electrolyte. For example, the electrolyte is a liquid solution of an organic solvent and a lithium salt. The current collector 24, the current collector 26 is a thin metal plate or foil disposed on either side of the electrode stack 22, and its thickness is generally between 0.4 mm and 1 mm. The current collector may be made of, for example, copper or aluminum. The current collector 24, the current collector 26 is attached to the electrode stack, as will be described in further detail below, to transmit current to an external circuit. In addition, the current collector 24 has a first side 28 and a second side 30. The current collector 26 has a first side 32 and a second side 34.

[0036] Additional references Figure 2B ,like Figure 2A , a partial cross-sectional view of a battery cell 18 is shown showing the layers in a single electrode stack 22 according to the present disclosure. Each electrode stack 22 is composed of a negative electrode or anode electrode 40 extending from a first side of the electrode stack 22, a separator 42, and a positive electrode or cathode electrode 44 extending from a second side of the electrode stack 22. The anode electrode 40 is typically a thin metal plate or foil that includes an anode electrode sheet 46 (such as anode electrode sheet 46) for providing electrical connection between the anode electrode and the current collector 24. Figure 2A ). Similarly, cathode electrode 44 is a thin metal plate or foil that includes cathode electrode tab 48 for providing electrical connection between cathode electrode 44 and current collector 26.

[0037] The anode electrode 40 and the anode electrode sheet 46 are made of, for example, copper or other suitable materials, and are typically coated with graphite or graphite / silicon or other carbon-based materials or silicon oxide or lithiated silicon. The cathode electrode 44 and the cathode electrode sheet 48 are made of, for example, aluminum or other suitable materials, and are typically coated with metal oxides, such as lithium cobalt oxide (LCO) or nickel cobalt aluminum (NCA) or lithium iron / manganese phosphate (LFP / LFMP) or lithium-rich manganese (LMR). The different metals (copper anode and aluminum cathode) of the battery cell 18 produce a galvanic cell reaction in the battery cell 18. For example, the copper of the anode electrode 40 and the aluminum of the cathode electrode 44 have different standard reduction potentials and are separated from each other by the diaphragm 42. The aluminum with a lower potential will oxidize and release electrons, while the copper with a higher potential will reduce and accept electrons. This process of releasing and accepting electrons will produce a current that can be used to power the device.

[0038] The separator 42 is generally a thin porous film or material layer that is located between the anode electrode 40 and the cathode electrode 44 and prevents the anode electrode 40 and the cathode electrode 44 from contacting and causing a short circuit. The separator allows lithium ions to pass through and complete the circuit. Chemically stable porous composite materials, such as composite materials made of polyethylene (PE), polypropylene (PP) or other natural materials, can be used as separators 42. In addition, inorganic nanoparticles such as TiO2, SiO2, Al2O3 and ZrO2 can also be used to make the coating composite material used for the separator 42. The separator 42 increases the internal resistance of the battery cell 18, which reduces the power output and efficiency of the battery. The internal resistance depends on the thickness, porosity and composition of the separator 42. The separator 42 is also selected to withstand high temperatures and manage thermal runaway to prevent the temperature from running away due to exothermic reactions. In addition, the separator 42 has a high melting point and low shrinkage to avoid contact between the anode 40 and the cathode electrode 44. The separator 42 has sufficient mechanical strength to resist puncture, tearing or deformation during the manufacture and operation of the battery assembly. The separator 42 also has dimensionally stable and flexible properties to conform to the shape of the electrode and accommodate volume changes during cycling. The separator 42 is chemically inert and compatible with the electrolyte, electrodes, and other battery components. In addition, the separator 42 has a low affinity for water or other impurities that could contaminate the electrolyte or cause corrosion of the electrode.

[0039] Reference Figure 3 , shows a top view of an electrode stack 22, an electrode sheet 46, an electrode sheet 48, and a current collector 24, a current collector 26 according to the present disclosure. A first portion of the anode electrode sheet 46a (e.g., between 80% and 90% of the electrode sheet, 80-90 electrode sheets) is bent or swept along a first direction d1, and a second portion of the anode electrode sheet 46b (e.g., between 10% and 20% of the electrode sheet, 10-20 electrode sheets) is swept (bent) along an opposite direction d2. The first portion of the anode electrode sheet 46a is welded (e.g., laser welded) to the first side 28 of the current collector 24. The first portion of the electrode sheet 46a can be divided into several groups (e.g., a group of 10 electrode sheets), each of which is connected or welded to the first side 28 of the current collector 24. The first side 28 is close to and faces the electrode stack 22, and in a specific example, the distance from the electrode stack 22 is 3 mm. It should be understood that the current collector 24 can be spaced from the electrode stack 22 by various other distances (e.g., 2mm, 2.5mm, 3.5mm, etc.). In contrast, a second portion of anode electrode tab 46b of electrode stack 22 sweeps in the opposite direction d2 and bends over and around current collector 24. The second portion of anode electrode tab 46b bent around current collector 24 is welded to second side 30 of current collector 24.

[0040] Similarly, a first portion of the cathode electrode sheet 48a (e.g., 80% to 90% of the entire cathode electrode sheet, between 80 and 90 electrode sheets) is bent or swept along a first direction d1, and a second portion of the cathode electrode sheet 48b (e.g., 10% to 20% of the entire cathode electrode sheet, between 10 and 20 electrode sheets) is bent or swept along an opposite direction d2. The first portion of the cathode electrode sheet 48a is welded (e.g., laser welded) to the first side 32 (i.e., the third side) of the current collector 26 (i.e., the second current collector). The first side 32 is close to and faces the electrode stack 22, and in a specific example, the distance from the electrode stack 22 is 3 mm. It should be understood that the current collector 26 can be spaced from the electrode stack 22 by various other distances (e.g., 2 mm, 2.5 mm, 3.5 mm, etc.). Therefore, the second portion of the cathode electrode sheet 48b of the electrode stack 22 is swept along the opposite direction d2, and then bent over and around the current collector 26 to the second side 34 (i.e., the fourth side opposite to the third side) of the current collector 26. The second portion of the cathode electrode tab 48 b that is bent around the current collector 26 is welded to the second side 34 of the current collector 26 .

[0041] Reference Figure 4 , provides a side view of a battery cell 18, showing cathode electrode tab 48a, a first portion of cathode electrode tab 48b, and a second portion attached to current collector 26 according to the present disclosure. More specifically, the first portion of cathode electrode tab 48a is welded to first side 32 of current collector 26 (by a plurality of parallel welds 52). Figure 4 The dashed line in the figure indicates and is described above and in Figure 3 ). Each parallel weld 52 is located at a surface portion 57 (welding surface portion) of the first side 32. The parallel welds 52 sweep the current collector 26 along the first welding direction dw1. In one aspect of the present disclosure, Figure 4 As shown, the first portion of cathode electrode sheet 48a is welded to first side 32 of current collector 26 by a series of ten parallel welds 52. However, in other aspects of the present disclosure, it is contemplated that there may be fewer (i.e., five or less) parallel welds 52 or more (i.e., twelve or more) parallel welds 52.

[0042] In addition, the second portion of the electrode sheet 48b is welded to the second side 34 of the current collector 26 by a single weld 54. The single weld 54 is located at a surface portion 61 of the second side 34. The single weld 54 is formed along a second welding direction d w2 Sweep the current collector 26. Second welding direction d w2 Perpendicular to the first welding direction d w1 For example, the set of parallel welds 52 and the single weld 54 are laser welds.

[0043] Thus, a first portion of anode electrode tab 46a is welded to first side 28 of current collector 24 in a manner similar to that described above with respect to a first portion of cathode electrode tab 48a on first side 32 of current collector 26. Likewise, a second portion of anode electrode tab 46b is welded to second side 30 of current collector 24 in a manner similar to that described above with respect to a second portion of cathode electrode tab 48b on second side 34 of current collector 26.

[0044] Reference Figure 5 , a flow chart of a method 100 for laser welding anode electrode sheets 46a, 46b and cathode electrode sheets 48a, 48b to current collectors 24, 26 is shown according to the present disclosure. The method begins at box 102, where a first portion and a second portion of the anode electrode sheet 46a and the cathode electrode sheet 48a are welded along a first direction d w1 Sweep, and then the second portion of the anode electrode sheet 46b and the cathode electrode sheet 48b moves along the second direction d w2 Sweep. For example, sweeping the electrode sheets 46a, 46b, 48a, 48b includes using, for example, a clamping tool and / or a welding machine to at least partially sweep and / or bend the first anode electrode sheet 46a and the first cathode electrode sheet 48a and the second anode electrode sheet 46b and the second cathode electrode sheet 48b in a lap-joint configuration in a first direction. In the lap-joint configuration, the ends of the first electrode sheets 46a, 48a overlap each other as they are swept and / or bent. The first direction d w1 Including a direction parallel to the surface of the electrode stack 22 , a plurality of first anode electrode tabs 46 a and first cathode electrode tabs 48 a and a plurality of second electrode tabs 46 b , 48 b extend from the electrode stack 22 .

[0045] The method then moves to box 104. Box 104 shows laser welding a plurality of first anode electrode sheets 46a and first cathode electrode sheets 48a to the first side 28, 32. Laser welding a plurality of first anode electrode sheets 46a and cathode electrode sheets 48a includes, for example, using a laser welder. The laser welder welds 80% to 90% of the first anode electrode sheets 46a and first cathode electrode sheets 48a (e.g., 80 electrode sheets and 90 electrode sheets) to the first side 28, 32 of the current collector 24, 26, thereby generating a set of between 5 and 10 parallel welds 52.

[0046] Next, box 106 shows bending a plurality of second anode electrode tabs 46b and second cathode electrode tabs 48b along a second welding direction dw2 onto the top of the current collectors 24, 26. Bending the plurality of second anode electrode tabs 46b and second cathode electrode tabs 48b includes using, for example, a clamping tool and / or a welding machine to bend 10% to 20% of the second anode electrode tabs 46b and second cathode electrode tabs 48b (e.g., 10-20 tabs) onto one side of the current collectors 24, 26 to prepare the second anode and cathode electrode tabs 46b, 48b for welding to the second side 30, 34 of the current collectors 24, 26. The second side 30, 34 faces away from the electrode stack 22 (e.g., at the distal end of the electrode stack 22).

[0047] Then box 108 shows laser welding the plurality of second anode electrode sheets 46b and second cathode electrode sheets 48b to the second sides 30, 34 of the current collectors 24, 26. Laser welding the plurality of second anode electrode sheets 46b and second cathode electrode sheets 48b includes using a laser welder. The laser welder welds the second anode electrode sheets 46b and second cathode electrode sheets 48b to a single weld 54. The resulting single weld 54 of the second anode electrode sheets 46b and second cathode electrode sheets 48b is oriented perpendicular to the parallel welds 52 of the first anode electrode sheets 46a and first cathode electrode sheets 48a, but is located on the second sides 30, 34.

[0048] The present disclosure has many advantages and benefits over prior art battery cells. For example, welding the first portion 46a, 48a of the electrode sheet 46, 48 to the first side 28, 32 of the current collector 24, 26, and then sweeping the second portion 46b, 48b of the electrode sheet 46, 48 and welding it to the second side 30, 34 of the current collector 24, 26, allows one current collector 24, 26 to be used for multiple anode electrode sheets 46 and one current collector 24, 26 to be used for multiple cathode electrode sheets 48. Using one current collector 24, 26 instead of multiple current collectors for each of the multiple electrode sheets 46, 48 reduces the overall resistance within the battery cell, thereby reducing heat generation. In addition, eliminating the need for multiple current collectors reduces the space occupied by the current collectors within the battery cell.

[0049] This description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, as other modifications will become apparent after studying the drawings, the description and the appended claims.

Claims

1. A battery cell, comprising: a plurality of first electrodes, wherein each of the plurality of first electrodes has an electrode sheet; a plurality of second electrodes, wherein each of the plurality of second electrodes has an electrode sheet; and A current collector has a first side and a second side, wherein each electrode tab of the plurality of first electrodes is coupled to the first side, and wherein each electrode tab of the plurality of second electrodes is coupled to the second side. 2 . The battery cell according to claim 1 , wherein the first side surface has a plurality of surface portions, and the plurality of surface portions are used to couple each electrode sheet of the plurality of first electrodes. 3 . The battery cell according to claim 1 , wherein the second side has a single surface portion for coupling each electrode tab of the plurality of second electrodes. 4 . The battery cell according to claim 1 , wherein the plurality of electrode sheets of the second electrode are wrapped on the second side and stacked together.

5. The battery cell of claim 1, wherein the electrode sheets of the plurality of first electrodes are divided into groups, wherein each group is coupled to the first side of the current collector, and wherein the plurality of first electrodes comprises between 80% and 90% of the plurality of first electrodes and the plurality of second electrodes. 6 . The battery cell according to claim 1 , wherein electrode tabs of the plurality of second electrodes coupled to the second side are bent in an opposite direction to electrode tabs of the plurality of first electrodes coupled to the first side. 7 . The battery cell according to claim 1 , wherein the first side surface includes a weld surface portion coupled to electrode tabs of the plurality of first electrodes.

8. The battery cell of claim 1, wherein the current collector has a thickness between 0.4 mm and 1 mm. 9 . The battery cell of claim 1 , wherein a first side of the current collector faces toward an electrode stack and a second side of the current collector faces away from the electrode stack.

10. The battery cell of claim 1, wherein the distance from the current collector to the electrode stack is 3 mm.

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