TWI398031B - Lithium ion battery assembly - Google Patents

Description

Lithium-ion battery pack

The invention relates to a lithium ion battery pack.

Previous lithium ion batteries are generally classified into two types, a wound type and a laminated type, which include an outer casing, a positive electrode sheet encapsulated in the outer casing, a negative electrode sheet, a separator, and an electrolyte. The separator is disposed between the positive electrode tab and the negative electrode tab. The electrolyte sufficiently wets the positive electrode sheet, the negative electrode sheet, and the separator. The positive electrode sheet includes a positive electrode current collector and a positive electrode material layer formed on the surface of the positive electrode current collector. The negative electrode sheet includes a negative electrode current collector and a negative electrode material layer formed on a surface of the negative electrode current collector.

The stacked lithium ion battery may include a plurality of positive and negative sheets that are overlapped and disposed by a separator. In order to reduce the thickness of the lithium ion battery, the press-fitting between the positive and negative electrode sheets is relatively tight, which makes it difficult to inject the electrolyte between the positive and negative electrode sheets. The larger the area of the positive and negative electrode sheets, the more difficult it is to inject the electrolyte. Therefore, in order to make the electrolyte permeable and fully wet to the middle of the positive and negative electrode sheets, it is usually necessary to leave the lithium ion battery after the electrolyte injection for a long time in the manufacturing process. This shortcoming is particularly evident in the manufacturing process of large power batteries. The power of the large battery after injection of the electrolyte often needs to be placed for more than ten hours or even longer, which greatly affects the production efficiency of the lithium ion battery. In addition, the tightly pressed positive and negative electrode sheets make it difficult for the gas generated inside the lithium ion battery to be discharged outward during charging and discharging, which affects the performance of the lithium ion battery.

In view of this, it is necessary to provide a lithium ion battery pack which is easy to inject an electrolyte and which is easy to discharge during use.

A lithium ion battery pack comprising a plurality of battery cells electrically connected to each other, the battery cells comprising a positive electrode sheet and a negative electrode sheet laminated and spaced apart, the positive electrode sheet having at least one first through hole, the negative electrode sheet having at least one a second through hole corresponding to the first through hole position.

A lithium ion battery pack comprising a plurality of battery cells electrically connected to each other, the battery cells comprising a plurality of positive electrode sheets and a plurality of negative electrode sheets, the plurality of positive electrode sheets and the plurality of negative electrode sheets being alternately stacked and spaced apart, each of the positive electrode sheets having And a plurality of first through holes, each of the negative electrode sheets having a plurality of second through holes, each of the second through holes corresponding to one of the first through holes.

Compared with the prior art, the positive and negative electrodes of the lithium ion battery have a through hole, so that the electrolyte easily enters from the through hole and penetrates into the middle of the positive and negative plates, and the lithium ion is charged and discharged. Gas generated inside the battery pack is easily discharged from the through hole.

10,20,30‧‧‧Lithium-ion battery pack

12‧‧‧ positive terminal

14‧‧‧native terminal

16‧‧‧Connecting piece

18‧‧‧Battery fastening device

100‧‧‧Lithium-ion battery cells

102‧‧‧ positive film

104‧‧‧Negative film

106‧‧‧Separator

108‧‧‧External package structure

112‧‧‧ positive current collector

122‧‧‧positive material layer

114‧‧‧Negative current collector

124‧‧‧Negative material layer

130a‧‧‧ positive ear

130b‧‧‧naked ear

132‧‧‧First through hole

134‧‧‧second through hole

1 is a schematic view showing the external structure of a battery cell of a lithium ion battery pack according to an embodiment of the present invention.

2 is a schematic view showing the internal structure of a battery cell of a lithium ion battery pack according to an embodiment of the present invention.

3 is a cross-sectional view of the battery cell of FIG. 2 taken along line III-III.

4 is a schematic view showing the cooperation of the through hole of the positive electrode tab and the through hole of the negative electrode tab.

Fig. 5 is a circuit diagram showing the connection of a plurality of battery cells of a lithium ion battery pack according to Embodiment 1 of the present invention.

6 is a schematic view showing the structural cooperation of a plurality of battery cells of a lithium ion battery pack according to Embodiment 1 of the present invention.

Fig. 7 is a circuit diagram showing the connection of a plurality of battery cells of a lithium ion battery pack according to Embodiment 2 of the present invention.

8 is a schematic view showing the structural cooperation of a plurality of battery cells of a lithium ion battery pack according to Embodiment 2 of the present invention.

Fig. 9 is a circuit diagram showing the connection of a plurality of battery cells of a lithium ion battery pack according to Embodiment 3 of the present invention.

FIG. 10 is a schematic view showing the structure of a plurality of battery cells of a lithium ion battery pack according to Embodiment 3 of the present invention.

The lithium ion battery pack provided by the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

Embodiments of the present invention provide a lithium ion battery pack 10 including a plurality of lithium ion battery cells 100 connected in series or in parallel with each other.

Referring to FIGS. 1 and 2 , the lithium ion battery cell 100 includes a positive electrode sheet 102 , a negative electrode sheet 104 , a separator 106 , a non-aqueous electrolyte solution, and an outer package structure 108 . The outer package structure 108 encloses the positive electrode sheet 102, the negative electrode sheet 104, the separator 106, and the non-aqueous electrolyte solution therebetween. The positive electrode tab 102 and the negative electrode tab 104 are stacked and spaced apart from each other by the separator 106. The laminated positive electrode sheet 102, negative electrode sheet 104, and separator 106 are bonded to each other. It can be understood that although FIG. 1 only shows a structure in which a positive electrode sheet 102 and two negative electrode sheets 104 overlap, the lithium ion battery cell 100 may include a plurality of positive electrode sheets 102 and a plurality of negative electrode sheets 104 alternately stacked, each two adjacent There is a separator between the positive electrode sheet and the negative electrode sheet. The number of the positive electrode sheets 102 and the negative electrode sheets 104 is not limited, and the positive electrode sheets 102 and the negative electrode sheets 104 may be one layer to 100 layers or more, and preferably 20 layers to 50 layers.

Referring to FIG. 3 , the positive electrode sheet 102 includes a sheet-shaped positive electrode current collector 112 and a positive electrode material layer 122 formed on a surface of the positive electrode current collector 112 opposite to the negative electrode current collector 114 . The negative electrode sheet 104 includes a sheet-shaped negative electrode current collector 114 and a negative electrode material layer 124 formed on a surface of the negative electrode current collector 114 opposite to the positive electrode current collector 112. Preferably, the positive electrode sheet 102 has two positive electrode material layers 122 respectively formed on two opposite surfaces of the positive electrode current collector 112, and the negative electrode sheet 104 has two negative electrode material layers 124 formed on the opposite surfaces of the negative electrode current collector 114, respectively. . After the positive electrode sheet 102 and the negative electrode sheet 104 are stacked, the positive electrode material layer 122 and the negative electrode material layer 124 are spaced apart from each other by the separator 106, and are disposed in contact with the separator 106. The positive current collector 112 may also have a positive electrode tab 130a extending outside the positive electrode material layer 122. The negative current collector 114 may also have a negative electrode tab 130b extending outside the negative electrode material layer 124. The positive electrode tab 130a and the negative electrode tab 130b are used for The circuit outside the lithium ion battery cell 100 is electrically connected. When the plurality of positive electrode sheets 102 and the plurality of negative electrode sheets 104 are alternately stacked, the positive electrode tabs 130a of the plurality of positive electrode current collectors 112 overlap each other, the negative electrode tabs 130b of the plurality of negative electrode current collectors 114 overlap each other, and the positive electrode ears of the positive electrode current collector 112 130a is provided separately from the negative electrode tab 130b of the negative current collector 114.

The positive electrode sheet 102 has at least one first through hole 132 having at least one second through hole 134 corresponding to the first through hole 132. The first through hole 132 and the second through hole 134 provide a flow passage for the electrolyte to allow the electrolyte on the surface of the positive electrode sheet 102 and the negative electrode sheet 104 to flow between the positive electrode sheet 102 and the negative electrode sheet 104. Preferably, the positive electrode sheet 102 and the negative electrode sheet 104 each have a plurality of first through holes 132 and second through holes 134 which are substantially uniformly distributed on the positive electrode sheet 102 and the negative electrode sheet 104. The first through holes 132 formed on the positive electrode tab 102 communicate the two opposite surfaces of the positive electrode tab 102, and the second through holes 134 formed in the negative electrode tab 104 allow the opposite surfaces of the negative electrode tab 104 to communicate. It can be understood that the number of the first through holes 132 and the second through holes 134 is related to the area of the positive electrode sheet 102 and the negative electrode sheet 104. When the lithium ion battery cell 100 is small, such as the sides of the positive electrode sheet 102 and the negative electrode sheet 104. When the length is less than or equal to 10 cm, a first through hole 132 may be formed only in the center of the positive electrode sheet 102, and a second through hole 134 corresponding to the position of the first through hole 132 may be formed in the center of the negative electrode sheet 104.

Since the positive electrode sheet 102 and the negative electrode sheet 104 have a first through hole 132 and a second through hole 134 as a whole, the positive electrode material layer 122, the positive electrode current collector 112, the negative electrode material layer 124, and the negative electrode current collector 114 also have through holes, and The through hole of the positive electrode material layer 122 is aligned with the through hole edge of the positive electrode current collector 112, and the through hole of the negative electrode material layer 124 is aligned with the through hole edge of the negative electrode current collector 114. The second through holes 134 on each of the negative electrode sheets 104 correspond to the first through holes 132 on one of the positive electrode sheets 102. That is, the number of the first through holes 132 on the positive electrode sheet 102 may be greater than the number of the second through holes 134 of the negative electrode sheet 104. Preferably, the first through hole 132 and the second through hole 134 are equal in number, and the first through hole 132 and the second through hole 134 are in one-to-one correspondence. When the positive electrode sheet 102 and the negative electrode sheet 104 are stacked, the axes of the first through holes 132 and the second through holes 134 of the positive electrode sheet 102 and the negative electrode sheet 104 are substantially aligned. Of course, The positive electrode sheet 102 and the negative electrode sheet 104 are first formed with the first through hole 132 and the second through hole 134, and then assembled with the separator 106, so that they are disposed between the positive electrode sheet 102 and the negative electrode sheet 104. The separator 106 is a complete structure and does not have the first through hole 132 and the second through hole 134 similar to the positive electrode tab 102 and the negative electrode tab 104, thereby preventing short circuit between the positive electrode tab 102 and the negative electrode tab 104.

The first through hole 132 and the second through hole 134 of the positive electrode sheet 102 and the negative electrode sheet 104 are not limited in shape, and may be a circular hole, a square hollow, a rhombic hole, a triangular hole, a polygonal hole or a combination thereof. The first through hole 132 and the second through hole 134 corresponding to the positive electrode tab 102 and the negative electrode tab 104 may have a uniform shape, such as when the first through hole 132 on the positive electrode tab 102 is a circular hole, and the first pass The second through hole 134 of the negative electrode tab 104 corresponding to the hole 132 is also a circular hole. Each of the first through holes 132 and the second through holes 134 has an area of about 0.001 square millimeters to 13 square millimeters, and each of the first through holes 132 and the second through holes 134 has a side length or a diameter of about 50 micrometers to 4 squares. Millimeter. Preferably, the first through hole 132 and the second through hole 134 are circular holes having a diameter of 1 mm to 2 mm. The interval between the axes of the two adjacent first through holes 132 and the second through holes 134 on the same positive electrode sheet 102 and the negative electrode sheet 104 is from 1 cm to 50 cm, preferably 5 cm. The plurality of first through holes 132 and the second through holes 134 may be arranged in an array in rows and columns, or may be arranged in a divergent manner with the center of the positive electrode tab 102 and the negative electrode tab 104 as a center. The positive electrode sheet 102 and the negative electrode sheet 104 preferably have an opening ratio of less than 10%, more preferably less than 2%, such as from 1% to 1%. On the one hand, the smaller opening ratio can ensure that the surface of the positive current collector 112 and the negative current collector 114 can carry more active substances, thereby avoiding affecting the battery capacity; on the other hand, it can ensure that the positive current collector 112 and the negative current collector 114 have sufficient Strength, not broken due to extrusion.

Referring to FIG. 4 , the first through hole 132 of the positive electrode tab 102 may have a size greater than or equal to the size of the second through hole 134 of the negative electrode tab 104 . When the first through hole 132 and the second through hole 134 are circular holes, the diameter of the first through hole 132 is greater than or equal to the diameter of the second through hole 134. When the first through hole 132 and the second through hole 134 are rectangular holes, the side length of the first through hole 132 is greater than or equal to the side length of the second through hole 134. Preferably, the size of the first through hole 132 of the positive electrode sheet 102 is larger than that of the negative electrode sheet 104. The second through hole 134 is provided with a margin for the position of the second through hole 134 of the negative electrode tab 104, which is easy to assemble. The positive electrode sheet 102 and the negative electrode sheet 104 are disposed in parallel. When the positions of the positive electrode sheet 102 and the negative electrode sheet 104 of the first through hole 132 and the second through hole 134 are slightly deviated rather than precisely aligned, the film is perpendicular to the positive electrode sheet 102. In the direction of the negative electrode sheet 104, the first through hole 132 of the positive electrode sheet 102 surrounds the second through hole 134 of the negative electrode sheet 104, so that the second through hole 134 of the negative electrode sheet 104 is located at the first through hole 132 of the positive electrode sheet 102. The range of the positive electrode material layer 122 of the entire positive electrode sheet 102 corresponds to the negative electrode material layer 124 of the negative electrode tab 104. Since the positive electrode material layer 122 contains lithium, this arrangement is such that from the positive electrode sheet 102 to the negative electrode sheet 104, since the negative electrode material layer 124 always corresponds to the positive electrode material layer 122, lithium ions are prevented from being directly precipitated as metallic lithium. To improve the safety of the battery. Preferably, the side length or diameter of the first through hole 132 of the positive electrode sheet 102 is 1.5 to 2 times the side length or diameter of the second through hole 134 of the negative electrode sheet 104. In this embodiment, the side length or diameter of the first through hole 132 of the positive electrode sheet 102 is 2 mm, and the side length or diameter of the second through hole 134 of the negative electrode sheet 104 is 1 mm. When the lithium ion battery cell 100 includes a plurality of positive electrode sheets 102 and a plurality of negative electrode sheets 104 overlapping each other, the axes of the first through holes 132 and the second through holes 134 in the plurality of positive electrode sheets 102 and the negative electrode sheets 104 are substantially mutually The alignment, or at least the second through hole 134 of the negative electrode tab 104 can be located within the range of the first through hole 132 of the positive electrode tab 102. Preferably, the first through holes 132 of the plurality of positive electrode sheets 102 are in one-to-one correspondence with the second through holes 134 of the plurality of negative electrode sheets 104.

The positive current collector 112 and the negative current collector 114 are metal foils. The positive current collector 112 may be an aluminum foil or a titanium foil, and the negative current collector 114 may be a copper foil or a nickel foil. The cathode current collector 112 and the anode current collector 114 have a thickness of 1 μm to 200 μm. The positive electrode material layer 122 includes a positively-active positive electrode active material, a conductive agent, and a binder. The negative electrode material layer 124 includes a negatively mixed negative electrode active material, a conductive agent, and a binder. The positive electrode active material may be lithium manganate, lithium cobaltate, lithium nickelate or lithium iron phosphate, etc., and the negative electrode active material may be natural graphite, organic cracked carbon or mesocarbon microbeads (MCMB), etc., the conductive agent may be The acetylene black or carbon fiber or the like may be polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE). It can be understood that the positive electrode active material and the negative electrode active material Other commonly used materials can also be used for the quality, the conductive agent and the binder. The positive electrode sheet 102 has an overall thickness of from about 100 micrometers to about 300 micrometers, preferably 200 micrometers. The negative electrode sheet 104 has an overall thickness of from about 50 micrometers to about 200 micrometers, preferably 100 micrometers.

The separator 106 may be a polypropylene microporous membrane, and the electrolyte salt in the electrolyte may be lithium hexafluorophosphate, lithium tetrafluoroborate or lithium bis(oxalate)borate, and the organic solvent in the electrolyte may be ethylene carbonate. Diethyl carbonate or dimethyl carbonate, and the like. It can be understood that the separator 106 and the electrolyte can also be made of other commonly used materials. In addition, the electrolyte may be replaced by a solid electrolyte membrane or an ionic liquid. When the lithium ion battery has a solid electrolyte membrane, the solid electrolyte membrane further replaces the separator 106, and is disposed on the cathode material layer 122 and the anode material. Between layers 124.

The outer package structure 108 can be a rigid battery case or a soft package bag. The 130 is exposed outside of the outer package structure 108 to enable electrical connection of the lithium ion battery cell 100 to an external circuit.

Example 1

Referring to FIG. 5 and FIG. 6, this embodiment provides a lithium ion battery pack 10 including a plurality of lithium ion battery cells 100 connected in series with each other. Each of the lithium ion battery cells 100 may further include a positive terminal 12 and a negative terminal 14. The positive terminal 12 is electrically connected to all of the positive ears 130a of the lithium ion battery cell 100, and the negative terminal 14 is electrically connected to all of the negative ears 130b of the lithium ion battery cell 100. The plurality of lithium ion battery cells 100 can be stacked on each other, and the positive electrode terminal 12 and the negative electrode terminal 14 of the plurality of lithium ion battery cells 100 are staggered with each other to make the positive electrode terminal 12 of a lithium ion battery cell 100 and The negative terminal 14 of the other lithium ion battery cell 100 is brought close to facilitate the series connection between the lithium ion battery cells 100.

The lithium ion battery pack 10 can further include a plurality of connecting pieces 16 and a battery fastening device 18. The tab 16 electrically connects the positive terminal 12 of a lithium ion battery cell 100 to the negative terminal 14 of an adjacent lithium ion battery cell 100. The battery fastening device 18 is configured to fix the lithium ion battery The cell unit 100 is disposed at the periphery and the bottom of the plurality of lithium ion battery cells 100 stacked together so that movement and misalignment between the lithium ion battery cells 100 are prevented.

The number of the plurality of lithium ion battery cells 100 is not limited. In this embodiment, three lithium ion battery cells 100 are connected in series to each other to form the lithium ion battery pack 10. The total voltage of the lithium ion battery pack 10 can be increased by connecting the lithium ion battery cells 100 in series. When the operating voltage of the lithium ion battery cell 100 is V ₀ , the operating voltage of the lithium ion battery 10 obtained in series is V=V ₀ ×n. Where n is the number of lithium ion battery cells 100 in the lithium ion battery pack 10.

Example 2

Referring to FIG. 7 and FIG. 8 , the present embodiment provides a lithium ion battery pack 20 including a plurality of lithium ion battery cells 100 , a plurality of connecting pieces 16 , and a battery fastening device 18 connected in parallel with each other. Each of the lithium ion battery cells 100 further includes a positive terminal 12 and a negative terminal 14. The lithium ion battery pack 20 of the second embodiment has substantially the same structure as the lithium ion battery pack 10 of the first embodiment, except that in the lithium ion battery pack 20, the positive terminal posts 12 of all the lithium ion battery cells 100 are identical. Nearly, the negative terminal 14 of all the lithium ion battery cells 100 are close to each other to facilitate parallel connection between the lithium ion battery cells 100.

The number of the plurality of lithium ion battery cells 100 is not limited. In this embodiment, three lithium ion battery cells 100 are connected in parallel to each other to form the lithium ion battery pack 20. The total capacity of the lithium ion battery pack 20 can be increased by connecting the lithium ion battery cells 100 in parallel. When the capacity of the lithium ion battery cell 100 is C ₀ , the total capacity of the lithium ion battery 20 obtained in parallel is C=C ₀ ×n. Where n is the number of lithium ion battery cells 100 in the lithium ion battery pack 20.

Example 3

Referring to FIG. 9 and FIG. 10, the present embodiment provides a lithium ion battery pack 30 including m units connected in parallel with each other, each unit including an equal number of n lithium ion battery cells 100 connected in series. The connecting piece 16 and a battery fastening device 18 are connected. Each of the lithium ion battery cells 100 further includes a positive terminal 12 and a negative terminal 14. The lithium ion battery pack 30 in this embodiment has substantially the same structure as the lithium ion battery pack 10 of the first embodiment, except that a positive electrode terminal 12 of one lithium ion battery cell 100 and another lithium ion are in each unit. The negative terminal 14 of the battery cell 100 is close to facilitate the series connection between the lithium ion battery cells 100 inside the unit, and the positive terminal 12 between the plurality of units is close to facilitate parallel connection between the plurality of units. .

The number of the plurality of lithium ion battery cells 100 is not limited. In this embodiment, two cells are connected in parallel with each other, and each cell has three lithium ion battery cells 100 connected in series with each other. The total capacity and total voltage of the lithium ion battery pack 30 can be increased by connecting the lithium ion battery cells 100 in series and in parallel. When the capacity of the lithium ion battery cell 100 is C ₀ and the operating voltage is V ₀ , the total capacity of the lithium ion battery 30 obtained after series and parallel connection is C=C ₀ × m, and the total voltage is V=V ₀ ×n. Where m is the number of cells connected in parallel in the lithium ion battery 30, and n is the number of lithium ion battery cells 100 in one cell.

It can be understood that the electrical connection manner between the plurality of lithium ion battery cells 100 in the lithium ion battery pack is not limited to the connection manner in the foregoing embodiments 1-3. For example, the plurality of lithium ion battery cells 100 may be first connected in parallel to form a plurality of cells, and the plurality of cells may be connected in series to form the lithium ion battery pack. In addition, other circuit components such as capacitors, resistors, inductors, etc. may be connected inside the lithium ion battery pack.

The method for preparing a lithium ion battery cell 100 in the lithium ion battery pack of the embodiment of the invention mainly comprises the following steps: step one, providing a positive current collector 112 and a negative current collector 114; and step two, respectively, the positive current collector 112 The positive electrode material layer 122 and the negative electrode material layer 124 are evenly coated on the surface of the negative electrode current collector 114 to form the positive electrode sheet 102 and the negative electrode sheet 104. In the third step, the first through holes 132 corresponding to the positions are formed on the positive electrode sheet 102 and the negative electrode sheet 104. second The via 134; and the fourth step, the positive electrode 102 and the negative electrode 104 are packaged into an external package structure 108.

In the second step, the cathode current collector 112 and the anode current collector 114 can be coated by a coater. Specifically, the positive electrode active material and the negative electrode active material are separately mixed with the conductive agent and the binder solution to form a positive electrode slurry and a negative electrode slurry, and the positive and negative electrode pastes are respectively applied to the positive electrode current collector by a coater. 112. The surface of the anode current collector 114 is dried and formed to form a cathode material layer 122 and a cathode material layer 124. Further, the applied positive electrode material layer 122 and negative electrode material layer 124 may be compacted by a laminator.

In the foregoing step 3, the method of forming the first through holes 132 and the second through holes 134 may be a method such as a stamping method or a laser etching method. The first through hole 132 and the second through hole 134 having a smaller size can be formed by laser etching. The first through hole 132 and the second through hole 134 are formed after the positive electrode material layer 122 and the negative electrode material layer 124 are formed, thereby avoiding separately coating the positive electrode current collector 112 and the negative electrode current collector 114 before opening. When the slurry leakage or adhesion occurs, the first through hole 132 and the second through hole 134 are blocked. The first through hole 132 and the second through hole 134 are formed at positions corresponding to the positive electrode tab 102 and the negative electrode tab 104. Specifically, the positive electrode tab 102 and the negative electrode tab 104 having the same size can be fixed by the positioning device. Punch the same position.

When the lithium ion battery pack uses an electrolyte or an ionic liquid, the foregoing step 4 may further include: (1) providing a separator 106, and placing the positive electrode sheet 102 and the negative electrode sheet 104 on both sides of the separator 106 and pressing together; And (2) injecting an electrolyte or an ionic liquid into the positive electrode sheet 102 and the negative electrode sheet 104 through the first through hole 132 and the second through hole 134, and the positive electrode sheet 102, the negative electrode sheet 104, the separator 106, and An electrolyte or ionic liquid is encapsulated in the outer package structure 108.

In the foregoing step (1), the separator 106 may be first laid on the surface of the positive electrode sheet 102, and then the negative electrode sheet 104 may be covered on the separator 106. During the assembly process, the positive electrode sheet should be made by the positioning device. The first through hole 132 on the 102 is aligned with the second through hole 134 on the negative electrode tab 104 as much as possible. When the lithium ion battery includes the plurality of positive electrode sheets 102 and the plurality of negative electrode sheets 104, the positive electrode sheets 102, the separators 106, and the negative electrode sheets 104 may be laminated in this order repeatedly to form a multilayer structure. The laminated positive electrode sheet 102, negative electrode sheet 104, and separator 106 can be pressed against each other by a laminator.

In the foregoing step (2), the electrolyte is injected between the positive electrode sheet 102 and the negative electrode sheet 104 through the through holes. Since the positive electrode tab 102 and the negative electrode tab 104 have a first through hole 132 and a second through hole 134, the electrolyte can quickly flow into the positive electrode tab 102 and the negative electrode through the first through hole 132 and the second through hole 134. Between the sheets 104, the entire positive electrode sheet 102, the negative electrode sheet 104, and the separator 106 are quickly wetted, which improves the production efficiency of the lithium ion battery pack. The larger the area of the positive electrode tab 102 and the negative electrode tab 104, especially in a power large battery, the more effective the effect of injecting the electrolyte from the through hole. Preferably, the positive electrode sheet 102 and the negative electrode sheet 104 may have an area greater than 400 square centimeters. When the positive electrode sheet 102 and the negative electrode sheet 104 are rectangular, the side length of the positive electrode sheet 102 and the negative electrode sheet 104 may be greater than 20 cm, preferably 50 cm to 100 cm.

When the lithium ion battery cell 100 employs a solid electrolyte, a solid electrolyte membrane may be directly disposed between the positive electrode sheet 102 and the negative electrode sheet 104 instead of the separator 106.

When the lithium ion battery pack is in use, since the positive electrode sheet 102 and the negative electrode sheet 104 have the first through hole 132 and the second through hole 134, the electrolyte or other substances between the positive electrode sheet 102 and the negative electrode sheet 104 are decomposed. The gas can be easily discharged.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧Lithium-ion battery cells

130a‧‧‧ positive ear

130b‧‧‧naked ear

132‧‧‧First through hole

134‧‧‧second through hole

Claims (19)

A lithium ion battery pack comprising a plurality of battery cells electrically connected to each other, each of the battery cells comprising a positive electrode sheet and a negative electrode sheet laminated and spaced apart, wherein the positive electrode sheet has at least one first through hole, The negative electrode sheet has at least one second through hole, and the at least one second through hole corresponds to the position of the at least one first through hole, and the positive electrode sheet and the negative electrode sheet have an opening ratio of less than 10%. The lithium ion battery pack according to claim 1, wherein the positive electrode sheet has a plurality of first through holes, and the negative electrode sheet has a plurality of second through holes, each of the second through holes and a first through hole correspond. The lithium ion battery of claim 1, wherein the at least one first through hole and the at least one second through hole are substantially aligned with each other. The lithium ion battery pack of claim 1, wherein the at least one first through hole has the same shape as the at least one second through hole. The lithium ion battery pack according to claim 1, wherein an area of the at least one first through hole is larger than an area of the at least one second through hole. The lithium ion battery pack according to claim 1, wherein the positive and negative electrode sheets are disposed in parallel, and the mutually corresponding second through holes are located in a direction perpendicular to the positive and negative electrode sheets. Within the range of the first through hole. The lithium ion battery pack according to claim 1, wherein the at least one first through hole and the at least one second through hole have a shape including a circular hole, a square space, a diamond hole, a triangular hole, and a polygonal hole. At least one. The lithium ion battery pack of claim 1, wherein each of the at least one first through hole and the at least one second through hole has an area of 0.001 square millimeter to 13 square millimeters, respectively. The lithium ion battery pack of claim 2, wherein the adjacent two first passes The spacing between the axis of the hole and the adjacent two second through holes is from 1 cm to 50 cm. The lithium ion battery pack according to claim 2, wherein each of the first through holes is a circular hole having a diameter of 2 mm, and each of the second through holes is a circular hole having a diameter of 1 mm, and one by one The axes are aligned. The lithium ion battery pack according to claim 10, wherein a spacing between axes of the adjacent two first through holes and the adjacent two second through holes is 5 cm. The lithium ion battery pack of claim 1, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer disposed on the surface of the positive electrode current collector, the negative electrode plate comprising a negative current collector and disposed thereon A layer of a negative electrode material on the surface of the negative current collector. The lithium ion battery pack according to claim 1, wherein the battery cell further comprises a separator that partitions the positive electrode sheet from the negative electrode sheet. The lithium ion battery pack according to claim 1, wherein the battery cell further comprises an electrolyte and an outer package structure, and the positive electrode sheet, the negative electrode sheet, the electrolyte and the separator are encapsulated in the outer package structure. The lithium ion battery pack according to claim 1, wherein the battery cell further comprises a solid electrolyte separating the positive electrode sheet from the negative electrode sheet. The lithium ion battery pack of claim 1, wherein the lithium ion battery pack further comprises a plurality of connecting pieces and a forbidden fastening device, the battery unit further comprising a positive terminal and a negative terminal. The positive terminal is electrically connected to the positive electrode, and the negative terminal is electrically connected to the negative electrode, and the plurality of battery cells are electrically connected by the plurality of connecting pieces and fixed by the fastening device. The lithium ion battery pack according to claim 1, wherein the plurality of battery cells are connected in series, in parallel, or in series and in parallel. A lithium ion battery pack comprising a plurality of battery cells electrically connected to each other, each of the battery cells comprising a plurality of positive electrode sheets and a plurality of negative electrode sheets, the plurality of positive electrode sheets and the plurality of negative electrode sheets being alternately laminated And spacing, the improvement is that each of the positive electrode sheets has a plurality of first through holes, each of the negative electrode sheets has a plurality of second through holes, each of the second through holes and one of the first through holes Corresponding to the holes, the opening ratio of each of the positive electrode sheets and each of the negative electrode sheets is less than 10%. The lithium ion battery pack of claim 18, wherein the second through holes are in one-to-one correspondence with the first through holes.