KR20140125862A - Lithium-ion battery - Google Patents

Abstract

A lithium ion battery 1 which is coupled in a casing 11 is disclosed which comprises at least one bare cell 12 each of which is connected between the separators 23, At least one anode plate 21 and a cathode plate 22 disposed alternately with each other and wherein the connector 13 connects the anode plate 21 and the cathode plate 22 together according to their respective polarities, Thereby forming a bus bar plate 14. The bus bar plate 14 is disposed along the edge of the bare cell 12 and the bus bar plate 14 is provided with a plurality of slits 15. Tabs 25 are provided on each of the anode plate 21 and the cathode plate 22. These tabs 25 of similar polarity are placed together to form a laminate of tabs of similar polarity along the edge of the bare cell 12. [ A method of manufacturing a lithium-ion battery 1 is also disclosed, comprising the steps of preparing a bare cell 12, arranging at least one bare cell 12 to form one or more stacks 81 of bare cells, ; And connector means (13) to connect the anode plate (21) and the cathode plate (22) together according to their respective polarities.

Description

Lithium-ion battery {LITHIUM-ION BATTERY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a lithium ion battery, and more particularly, to a lithium ion battery having tabs, which allow multilayer bare cells to be stacked in parallel and plates of a bare cell being connected together to form a high capacity lithium- ) Is provided on a lithium ion battery.

Lithium-ion batteries are rechargeable batteries, also known as secondary-cell batteries, used as an energy source in many configurations, shapes and sizes. Lithium-ion batteries are commonly used in consumer electronics. The battery is one of the most popular types of rechargeable batteries for portable electronic products such as cell phones, cameras, camcorders and laptops, and has one of the best energy density, non-memory effect and slow charge loss when not in use. As a result of recent developments, the battery has a new concept of battery and new electrode characteristics to improve the capacity and non-energy density of non-differential power supplies (UPS) for communication tower stations, renewable energy and various sizes of electric vehicles Sized high-power applications, such as an energy storage unit for high-power applications.

Lithium-ion batteries developed in the 1990s are becoming increasingly popular with higher operating voltages and energy densities compared to Ni-MH, Ni-Cd and lead sulfate batteries using aqueous electrolyte. The main disadvantage of lithium ion batteries is that their cylindrical and prismatic shapes require attention to battery performance and battery safety issues. Despite the popular use of cylindrical lithium ion batteries, there have been many reports of unpredictable explosions in these batteries. These explosions are due to a temporary increase in the pressure inside the battery. Also, in this structure, the radius of curvature of the central portion of the helix is small, which results in excessive stress often occurring at the bend surface of the electrode, so that the electrode is often stripped. In addition, a very long electrode plate is required to produce a high capacity battery, which results in an increase in internal impedance due to the longer electron path. In addition, prismatic lithium ion batteries are reported to have lower capacitance density and specific energy compared to cylindrical lithium ion batteries. The capacity of the battery is generally proportional to the amount of electrode active material.

In recent developments, the manufacturing cost of lithium ion batteries is also generally high. In traditional lithium-ion battery technology, the battery uses a number of cells that are connected in series or in parallel, depending on the required supplemental system. Thus, the additional material used in the final cell and the additional processing steps will result in higher manufacturing costs. There are also some disadvantages of the most important processes, which require great care and care, especially in the sealing process. Conventional sealing of the battery faces many problems including gas generation inside the battery and exfoliation of the sealed area, which affects the reliability and safety of the battery itself. In terms of welding, the most important factors of tap welding are the thickness and material of the tab and the terminal. In battery manufacturing, material bonding is required depending on the type, size and capacity of the battery material, such as tap-to-terminal connection and external electrical connection. The welding problem is caused by the limited electrode thickness that can be welded to form a high power lithium ion battery.

It is therefore an object of the present invention to provide a cell structure and a manufacturing method thereof that are reduced in time and more convenient due to the reduced process involved in manufacturing a lithium ion battery, which is proportional to cost reduction. Next, a high power lithium ion battery can be manufactured using a multi-layered cell together with a welding method for a high capacity associated with a small final cell. Welding techniques also allow the stratified structure of the bare cell to be stably interconnected without additional support or connection. In addition, it forms a flexible, rigid complete cell with a strong and rigid structure. The present invention also overcomes the problem of long winding play jellyroll systems in conventional Li-ion batteries, which have high internal impedance and limitations in layer welding in lithium polymer batteries.

It is an object of the present invention to provide a high power lithium ion battery having a multilayered bare cell structure including two or more bare cells connected in parallel.

It is a further object of the present invention to provide a method of manufacturing a lithium ion battery which is proportional to cost reduction, which is generally associated with reduced processing time due to fewer processes involved during the manufacture of high power lithium ion batteries and which is also convenient to manufacture.

It is still another object of the present invention to provide a method of manufacturing a lithium ion battery through various methods by an envelope separator method, a zigzag method, a winding method, or a flat jelly roll method.

It is still another object of the present invention to provide a method of manufacturing a lithium ion battery having a stable and reliable cell structure.

It is a further object of the present invention to provide a method of manufacturing a lithium ion battery in a shortened manufacturing process by eliminating several steps that reduce drag, machinery, material handling time requirements and also reduce failure rates.

These and other objects of the present invention are achieved by providing a method of manufacturing a lithium ion battery and a lithium ion battery as follows:

A lithium ion battery (1) coupled into a casing (11)

At least one bare cell (12) comprising at least an anode plate and a cathode plate alternating with each other between the separators; And

And connector means (13) for connecting said anode and cathode plates respectively according to their respective polarities,

The connector means 13 is formed of a pair of bus bar plates 14 which are arranged along the edge of the bare cell 12 and in which a plurality of slits 15 ) Are provided, and

A method of manufacturing a lithium ion battery,

a) preparing a bare cell (12) comprising at least an anode plate and a cathode plate alternately arranged between the separators (23); And

b) disposing at least one bare cell (12) to form one or more stacks (81) of bare cells; And

c) disposing a connector means (13), connecting said anode and cathode plate respectively according to their respective polarities,

The connector means 13 is formed of a pair of bus bar plates 14 each disposed along the edge of the bare cell 12 and a plurality of And tabs 25 disposed at the edges of the plates are provided on the anode plate and the cathode plate respectively and the tabs having similar polarities are disposed together to form the bare cell 12 ) Of tabs 25 of similar polarity along the edges of the bare cell to form another laminate of tabs 25 of similar polarity along the edges of the bare cell Lt; / RTI &

The method of manufacturing a lithium ion battery includes the steps of inserting the tabs 25 into respective slits 15 of the bus bar plate 14 to weld the tabs 25 onto the bus bar plate 14 Also included.

Hereinafter, embodiments of the present invention will be described by way of example only with reference to the accompanying drawings.

1 shows a perspective view of a lithium ion battery constructed in accordance with an embodiment of the present invention;
Figure 2 shows a perspective view of a method of manufacturing a bare cell using an enveloped separator of the present invention;
3 shows a perspective view of a method of manufacturing a bare cell using the zigzag method of the present invention;
4 shows a perspective view of a method of manufacturing a bare cell using the winding method of the present invention;
5 is a perspective view of a method of manufacturing a bare cell using the flat jelly-roll method of the present invention;
6 shows a bus bar plate for both terminals and negative terminals of the present invention;
Fig. 7 shows an explanatory diagram of steps of connecting the plate of the present invention and performing the ultrasonic spot welding process; Fig.
8 shows a perspective view of an integrated body of a bare cell of the present invention; And
Fig. 9 shows a manufacturing process flow of a lithium ion battery according to one embodiment of the present invention.

Referring to the drawings, and more particularly to Figures 1 and 2, there is shown a perspective view of a lithium ion battery of the present invention. The lithium ion battery 1 in particular comprises at least one bare cell 12, an anode plate 21, a cathode plate 22 arranged alternately between the separators 23, a bus bar 22 having a plurality of slits 15, A plate 14 and a welding plate 63. The electrochemical cell may be formed through a variety of methods such as an envelope separator, zigzag, and wound or flat jelly rolls. These structures, except for the flat jelly roll method, utilize a multi-layered electrode structure in which the anode and cathode electrode layers are cut to the required size and shape and then alternately stacked in proportion to the required capacity. The separator 23 is interposed between the anode electrode 21 and the cathode electrode 22 forming the bare cell 12 and as a result the positive electrode, the separator 23 and the negative electrode are repeatedly stacked. In addition, by calculating the capacity of one layer of the cell, the number of layers to be stacked to build the bare cell 12 can be easily determined. Such a plurality of bare cells 12 may be stacked to produce a battery having a practical capacity. The number of bare cells 12 to be stacked is proportional to the required capacity. For example, if the number of stacked cells increases, the number of overlapping electrodes also increases. In this regard, the use of double-sided coating electrodes for both the anode and the cathode reduces the thickness of the deposited electrode compared to using only a single side of the coating and current collector.

In this embodiment of the invention, the plurality of bare cells 12 are arranged such that the layers of each anode 21 and the cathode 22 overlap each other. The alignment of the overlapped bare cell 12 is also controlled. The bus bar plate 14 is disposed on both the right and left sides of the tab 25 and the nickel plate 62 is relatively lightweight for spot welding so that the bus bar plate 14 is made of nickel 62) bus. On the other hand, the aluminum (61) bus bar is used for the cathode terminal. The same alignment and arrangement of slits 15 are provided in the middle of the bus bar plate 14. Each slit 14 has a weld plate 63 which can be bent upward to form a flat surface. The tabs 25 are welded using an ultrasonic spot welding method. The finished welded cell is installed in a suitable Teflon casing 11.

Referring again to FIG. 2, this drawing illustrates a method of manufacturing a bare cell using the emboldened separator method of the present invention. As shown in Fig. 2A, the anode electrode 21 and the cathode electrode 22 are cut to the required dimensions. Next, the cut electrode has uncoated terminals for electronic connection. Next, as shown in FIG. 2B, the electrode anode 21 is encapsulated (24) by the enveloped separator 23, and the electrode cathode 22 is kept in the non-encapsulated state. Finally, as shown in Fig. 2C, the arrangement of the open tab terminals 25 of the anode electrode 21 and the cathode electrode 22 is located on each side.

3 and 4 show a perspective view of a method of manufacturing the bare cell 12 using the zigzag method and the winding method of the present invention. 3A and 4A, both of these methods use the same anode electrode 21, the separator 23, and the cathode electrode 22, which are sequentially applied, but in the case of the zigzag method and the winding method, Are arranged in different ways to fold the separator (23). Instead, the arrangement of the open tab terminals 25 of the anode electrode 21 and the cathode electrode 22 is located on both sides as shown in FIGS. 3B and 4B. Next, a sandwich structure between the anode electrode 21 and the cathode electrode 22 is formed by the zigzag method 31 and the winding method 41 to manufacture the bare cell 12 as shown in Figs. 3C and 4C. Are combined together.

5 shows a perspective view of a method of manufacturing the bare cell 12 using the flat jelly-roll method of the present invention. In this method, as shown in Fig. 5A, the anode electrode 21 and the cathode electrode 22 are cut into long members according to the required cell capacity. The cut electrode is sandwiched between the anode electrode 21, the separator 23, and the cathode electrode 22, wound into a cylindrical shape 52, and flattened as shown in Fig. 5B. Finally, the arrangement of the open tab terminals 25 of the anode electrode 21 and the cathode electrode 22 is located on each opposite side as shown in FIG. 5C. 5D shows that the arrangement of the open tab terminals of the anode electrode 21 and the cathode electrode 22 can be juxtaposed with each other.

Figs. 6 and 7 show a bus bar plate for both terminal and negative terminal, wherein the connection of this plate is accomplished by performing the ultrasonic spot welding method of the present invention. 6A shows a bus bar plate 14 which is preferably made of aluminum 61 and nickel 62 and is preferably made of a weld plate for connection to the positive and negative terminals of the completed lithium- 63 and a slit 15. There is also a slit 15 arranged in the same alignment in the middle of the bus bar plate 14. Each slit 15 has a weld plate 63 that can be bent upward to form a flat surface. The area of the slit 15 can be adjusted or changed depending on the thickness and the size of the tab 6, which functions as an electrode terminal of the bare cell 12 and is generally proportional to the capacity requirement of the battery. As the thickness of the anode tab 21 or the cathode tab 22 of each bare cell 12 increases, the area of the slit 15 must also be increased. The size of the bus bar 14 is not constant and may vary in various sizes according to the manufacturing requirements of the battery. In addition, such a bus bar 14 should be preferably mounted on the stacked cell 81. Referring to FIG. 7A, the tabs 25 are welded on the weld plate 63 using an ultrasonic spot welder to connect the electrode structures one by one to the terminals. Preferably, the welding process starts from the bottom and runs to the final bare cell 12. [ All parameters for the welding process must be properly controlled to prevent any mistakes. First, the bus bar plate 14 is mounted on the anode tab 21 of the bare cell 12. Next, the extended anode tabs 21 provided on the weld plate 63 are welded using an ultrasonic spot welder or other suitable welding technique. After the welding process is completed, the welded terminals are bent upward to form a flat surface. The process then continues for the other bare cell 12 until reaching the last bare cell 12. These bare cells 12 are overlapped and welded one by one until the capacity requirement is satisfied. Similarly, the bus bar plate 14 is also mounted on the cathode terminal 22 and welded together using the same ultrasonic spot welder or the like. After the welding process is completed, the welded terminals are bent upward to form a flat surface. In this regard, ultrasonic spot welding is typically a technique for forming robust structural welds and plays an important role in the case of complicated geometric shapes and difficult-to-access joint surfaces. The ultrasonic spot welder is applied to the upper and lower heads of the weld plate. As an alternative, the ultrasonic spot welder may also be applied to the upper head of the weld plate 63 to bend the weld plate 63 upwardly. Referring now to FIG. 6B, there is shown a bus bar plate 14 that does not have a weld plate 63. FIG. During this process, the tabs 25 of the bare cell 12 are folded and welded onto the bus bar plate 14 using an ultrasonic spot welder or the like to connect the electrode structure to the terminals. The next step is similar to that of the bus bar 14 with the weld plate 63.

Figure 8 shows a perspective view of a preassembled bare cell of the present invention. The arrangement of the plurality of bare cells 12 in an appropriately aligned state is superimposed and the tabs 25 are welded to the respective weld plates 63 in accordance with their respective polarities to form a connection for the production of the lithium- (Fig. 6A). During assembly of the cell, contamination of any moisture can adversely affect cell performance / performance. Therefore, strict control is required during the cell assembly process. Thus, the finished cell or complete cell is dried in an oven to remove any moisture and then enters the drying chamber or glove box for electrolyte filling.

Fig. 9 shows a manufacturing process flow of a lithium battery according to one embodiment of the present invention. In order to manufacture a lithium ion battery, a number of steps must be performed. From the preparation of the material to the lamination of the cells, the process of the present invention is the same as known. The present invention has some of the processes compared to the previous processes that have been removed, such as packaging bag cutting processes, bag forming processes, double-sided sealing processes, vacuum sealing processes, degassing processes, cell sorting and cell welding processes. When the cell stacking is completed after the common process, all the tabs are welded to the respective bus bar plates 14 in accordance with their respective clarity. Next, the completed welded cell is placed in an appropriate Teflon casing 11 before electrolyte injection. In this respect, the Teflon casing 11 is the best choice for leakage prevention due to the use of an electrolyte solution which requires a rigid casing. Teflon is a thermoplastic synthetic material that retains its unique properties due to its compositional characteristics. The following is the electrolytic dispensing process. Typically, the electrolyte is a mixture of ethylene carbonate or an organic carbonate such as diethyl carbonate containing a complex of lithium ions. Such non-aqueous electrolytes generally use non-degradable anionic salts such as lithium hexafluorophosphate (LiPF6). This liquid electrolyte is injected during packing. The final step in the manufacture of lithium ion batteries is to activate the cell. At the end of the line, the cell categorization step is performed using the cell cycler. The cell cycler (not shown) charges and discharges within a certain number of cycles. Depending on the specifications of the battery module, the capacity and power can be freely adjusted through serialization or parallelization. A battery management system (BMS) may also be coupled to the module cycler for the module conditioning process. In addition, a battery management system (BMS) is an electronic system that manages a rechargeable battery (a cell or a battery pack), for example, to monitor the state of the battery, calculate secondary data, report data, , Control the environment of the battery, and / or equilibrate the battery.

Still referring to FIG. 9, the present invention has the following advantages.

1. It provides various shapes and sizes that are effectively mounted on the equipment to be powered.

2. It is much lighter than the secondary battery of other equivalent energy.

3. Highly open circuit voltage compared to aqueous batteries (eg, lead-acid batteries, nickel-metal hybrids and nickel-cadmium). This is beneficial because it increases the amount of power that can be delivered at low voltages.

4. There is no memory effect.

5. A self-discharge rate of about 5-10% / month compared to about 1.25% / month for a low self-discharging NiMH battery and about 10% / month for a nickel-cadmium battery, 30% per month for a typical nickel metal hydride battery.

6. The components are environmentally safe since free lithium metal is not present.

It is contemplated that features of the present invention may be implemented to replace existing lithium ion batteries or may be used in the manufacture of new lithium ion batteries.

While the preferred embodiments of the invention have been described, it should be understood that various changes, adaptations and modifications may be effected therein. Therefore, it is to be understood that the invention is not limited to the details of the invention shown in the drawings, and that modifications of such details are obvious to those skilled in the art.

Claims (14)

A lithium ion battery (1) coupled into a casing (11)
At least one bare cell (12) comprising at least an anode plate and a cathode plate alternating with each other between the separators; And
And connector means (13) for connecting said anode and cathode plates respectively according to their respective polarities,
The connector means 13 is formed of a pair of bus bar plates 14 which are arranged along the edge of the bare cell 12 and in which a plurality of slits 15 A lithium ion battery is provided. The method according to claim 1,
And a welding plate (63) is disposed to extend from each of the slits (15). The method according to claim 1,
Each of the anode plate and the cathode plate is provided with a tab 25 disposed at the edge of the plate so as to be connected to the bus bar plate 14, The tabs 25 are arranged together along the edge of the cell 12 forming a laminate of the tabs 25 of similar polarity and the tabs 25 having other similar polarities are arranged along the edge of the cell 12, Are arranged together while forming another stack of tabs (25) of the lithium ion battery. The method of claim 3,
Each of said tabs (25) being inserted into and welded together into said respective slit (15). 5. The method of claim 4,
Wherein each of said tabs (25) is inserted into said respective slit (15) and welded together on said weld plate (22). 6. The method of claim 5,
The weld plate (63) is bent upwardly to form a flat surface to surround the tab (25). 7. The method according to any one of claims 1 to 6,
The bus bar plate 14 is made of aluminum 61 and nickel 62. The aluminum bus bar plate 61 is connected to the cathode plate and the nickel bus bar plate 62 is connected to the anode plate. . 6. The method of claim 5,
The bus bar plate 14 is formed in various sizes according to a desired capacity of the lithium ion battery. A method of manufacturing a lithium ion battery,
a) preparing a bare cell (12) comprising at least an anode plate and a cathode plate alternately arranged between the separators (23); And
b) disposing at least one bare cell (12) to form one or more stacks (81) of bare cells; And
c) disposing a connector means (13), connecting said anode and cathode plate respectively according to their respective polarities,
The connector means 13 is formed of a pair of bus bar plates 14 each disposed along the edge of the bare cell 12 and a plurality of And tabs 25 disposed at the edges of the plates are provided on the anode plate and the cathode plate respectively and the tabs having similar polarities are disposed together to form the bare cell 12 ) Of tabs 25 of similar polarity along the edges of the bare cell to form another laminate of tabs 25 of similar polarity along the edges of the bare cell Lt; / RTI &
Further comprising the step of inserting the tabs (25) into the respective slits (15) of the bus bar plate (14) to weld the tabs (25) onto the bus bar plate (14) Way. Wherein the tap (25) is welded to the welding plate (22) by ultrasonic spot welding, laser welding, or the like. 11. The method of claim 10,
The assembled lithium ion battery including the connected bus bar plates (14) is placed in the casing (11) for final packaging. 12. The method of claim 11,
And the electrolyte is distributed in the combined casing (11). 13. The method according to any one of claims 9 to 12,
Wherein the bus bar plate (14) is configured according to the number of the bare cell (12) configured according to the capacity of the desired battery. 14. The method of claim 13,
The multi-layered structure (81) of a bare cell is manufactured by an enveloped separator method, a zigzag method, a winding method, or a flat jellyroll method in a bare cell manufacturing method.

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