TWI418076B - Lithium ion power battery - Google Patents

Description

Lithium ion power battery

The invention relates to a lithium ion power battery.

Previous lithium ion power batteries are generally classified into two types, a wound type and a stacked 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 power battery may include a plurality of positive and negative plates that are overlapped and disposed by a diaphragm. In order to reduce the thickness of the lithium ion power battery, the pressing 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 enable the electrolyte to penetrate and fully infiltrate into the middle of the positive and negative electrode sheets, it is usually necessary to place the lithium ion power 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 power battery. In addition, the tightly pressed positive and negative electrode sheets make it difficult for the gas generated inside the lithium ion power battery to be discharged outward during charging and discharging, which affects the lithium ion power battery. The loop performance of the pool.

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

A lithium ion power battery having a power density of 500 watts/kg or more, comprising at least one battery cell, the battery cell comprising a positive electrode sheet and a negative electrode sheet stacked and spaced apart, wherein the positive electrode sheet The plurality of first through holes have a plurality of second through holes, and each of the second through holes is disposed corresponding to one of the first through holes.

A lithium ion power battery having a power density of 500 watts/kg or more, comprising at least one battery cell, the battery cell 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 The anode sheets are alternately stacked and spaced apart, wherein each of the positive electrode sheets has a plurality of first through holes, and each of the negative electrode sheets has a plurality of second through holes, each of the second through holes being disposed corresponding to one of the first through holes.

Compared with the prior art, the positive and negative electrodes of the lithium ion power battery have through holes, so that the electrolyte easily enters from the through holes and penetrates into the middle of the positive and negative plates, and the lithium ions are charged and discharged. The gas generated inside the power battery is easily discharged from the through hole.

100‧‧‧Lithium ion battery

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

130‧‧‧ Ears

132‧‧‧First through hole

134‧‧‧second through hole

140‧‧‧Battery protection circuit board

142‧‧‧Signal acquisition unit

1420‧‧‧Protected wafer

1422‧‧‧Voltage detection unit

1424‧‧‧current detection unit

1426‧‧‧ Temperature detection unit

144‧‧‧Control unit

1440‧‧‧Microcontroller

1442‧‧‧Switch unit

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

2 is a schematic diagram showing the internal structure of a battery cell in a lithium ion power battery according to an embodiment of the present invention; Figure.

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.

Figure 5 is a block diagram of a battery protection circuit board.

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

Referring to FIG. 1 to FIG. 4 , an embodiment of the present invention provides a lithium ion power battery 100 having a power density greater than or equal to 500 watts/kg (W/kg), including at least one battery cell. The battery cell 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. Preferably, the positive electrode sheet 102 and the negative electrode sheet 104 are disposed in parallel. It can be understood that the lithium ion power battery 100 can include a plurality of positive electrode sheets 102 and a plurality of negative electrode sheets 104 alternately stacked, and a diaphragm between each two adjacent positive electrode sheets and the negative electrode sheets. 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 1 to 100 layers or more, preferably 20 to 50 layers, respectively. Further, the capacity of the lithium ion power battery 100 may be 10 ampere-hours (Ah) or more.

Referring to FIG. 3, the positive electrode sheet 102 includes a sheet-shaped cathode current collector 112 and a positive electrode material layer formed on a surface of the cathode current collector 112 opposite to the anode current collector 114. 122. 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 and the negative current collector 114 may also have a tab 130 extending outside the positive electrode material layer 122 and the negative electrode material layer 124, respectively. The tab 130 is for electrical connection to a circuit external to the lithium ion power battery 100. When the plurality of positive electrode sheets 102 and the plurality of negative electrode sheets 104 are alternately stacked, the tabs 130 of the plurality of positive electrode current collectors 112 overlap each other, the tabs 130 of the plurality of negative electrode current collectors 114 overlap each other, and the tabs of the positive electrode current collector 112 are overlapped with each other. 130 is disposed separately from the tabs 130 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 power battery 100 is small, such as each positive electrode sheet. 102. When the side length of the negative electrode sheet 104 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 position corresponding to the position of the first through hole 132 may be formed in the center of the negative electrode sheet 104. Through hole 134. When the lithium ion power battery 100 is large, such as when the side length of the positive electrode sheet 102 and the negative electrode sheet 104 is greater than or equal to 50 cm, it is almost impossible to sufficiently inject the electrolyte into the positive electrode sheet 102 by the method of injecting the electrolyte. Between the negative electrode sheets 104, the plurality of first through holes 132 and the second through holes 134 are formed on the positive electrode sheet 102 and the negative electrode sheet 104, so that the electrolyte solution can be quickly and sufficiently injected into the positive electrode sheet 102 and the negative electrode sheet. Between 104. In addition, when the positive electrode sheet 102 and the negative electrode sheet 104 are respectively a plurality of layers, preferably, the plurality of second through holes 134 of the negative electrode sheet 104 are disposed in one-to-one correspondence with the plurality of first through holes 132 of the adjacent positive electrode sheets 102.

Since the positive electrode sheet 102 and the negative electrode sheet 104 have the first through hole 132 and the 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 tab 102 may be greater than the number of the second through holes 134 of the negative electrode tab 104. Preferably, the first through hole 132 and the second through hole 134 are equal in number. When the positive electrode sheet 102 and the negative electrode sheet 104 are laminated, the axes of the first through hole 132 and the second through hole 134 of the positive electrode sheet 102 and the negative electrode sheet 104 are substantially aligned. The positive electrode sheet 102 and the negative electrode sheet 104 are first formed in the first through hole 132 and the second through hole 134, and then assembled to the separator 106, so that the positive electrode sheet 102 and the negative electrode sheet 104 are disposed on the positive electrode sheet 102 and the negative electrode sheet 104. The separator 106 is a complete structure and does not have a first pass similar to the positive electrode tab 102 and the negative electrode tab 104. The hole 132 and the second through hole 134 prevent 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 hole, 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 sheet 102 and the negative electrode sheet 104 may have a uniform shape, such as when the first through hole 132 on the positive electrode sheet 102 is a circular hole, and the first The second through hole 134 of the negative electrode tab 104 corresponding to the through 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. 4 mm. 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 opening ratio of the positive electrode sheet 102 and the negative electrode sheet 104 is preferably less than 10%, more preferably less than 2%, such as 1% to 1%. On the one hand, the smaller opening ratio ensures that the surface of the positive current collector 112 and the negative current collector 114 can carry more active material to avoid 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 sheet 102 may have a size greater than or equal to the size of the second through hole 134 of the negative electrode sheet 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 first pass The side length of the 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 the second through hole 134 of the negative electrode sheet 104, thereby leaving a margin for the position of the second through hole 134 of the negative electrode sheet 104, which is easy to assemble. When the positions of the first through hole 132 and the second through hole 134 of the positive electrode tab 102 and the negative electrode tab 104 are slightly deviated rather than precisely aligned, the positive electrode tab 102 is perpendicular to the positive electrode tab 102 and the negative electrode tab 104. The first through hole 132 surrounds the second through hole 134 of the negative electrode tab 104 such that the second through hole 134 of the negative electrode tab 104 is located within the range of the first through hole 132 of the positive electrode tab 102, thereby making the positive electrode of the entire positive electrode tab 102 The material layers 122 each correspond 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 power battery 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 opposite to each other. 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.

The positive current collector 112 and the negative current collector 114 are metal foils, and the positive current collector 112 may be aluminum foil or titanium foil, and the negative current collector 114 may be copper foil or nickel foil. The positive current collector 112 and the negative 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 The pole material layer 124 includes a uniformly mixed anode 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 For B-black or carbon fiber, the binder may be polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE). It is to be understood that the positive electrode active material, the negative electrode active material, the conductive agent, and the binder may be other commonly used materials. The positive electrode sheet 102 has an overall thickness of about 50 micrometers to 300 micrometers, preferably 60 micrometers to 150 micrometers. The negative electrode sheet 104 has an overall thickness of about 30 micrometers to 200 micrometers, preferably 50 micrometers to 150 micrometers.

The separator 106 may be a polypropylene microporous membrane, a polypropylene/polyethylene composite membrane or a ceramic composite membrane, and the electrolyte salt in the electrolyte may be lithium hexafluorophosphate, lithium tetrafluoroborate or lithium bis(oxalate)borate. The organic solvent in the electrolytic solution may be ethylene carbonate, diethyl carbonate or dimethyl carbonate. It will be appreciated that other common materials may be employed for the membrane 106 and electrolyte. In addition, the electrolyte may be replaced by a solid electrolyte membrane or an ionic liquid. When the lithium ion power 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 layer. Between 124.

The outer package structure 108 can be a rigid battery case or a soft package bag. The tabs 130 of the positive current collector and the tabs 130 of the negative current collector are exposed outside of the outer package structure 108 to achieve electrical connection to an external circuit.

Further, the lithium ion power battery 100 may further include a plurality of battery cells connected in parallel or in series. Specifically, when the plurality of battery cells are connected in series, the tab 130 of the positive current collector 112 and the tab of the negative current collector 114 between the plurality of battery cells 130 are electrically connected alternately, that is, the tabs 130 of the positive current collector of each battery cell are electrically connected to the tabs 130 of the negative current collector of the other battery cell, thereby realizing the plurality of battery cells being connected in series with each other. The lithium-ion battery 100 has a rated voltage of an integral multiple of one battery cell and a rated capacity of one battery cell by the series connection of the plurality of battery cells. When the plurality of battery cells are connected in parallel, the tabs 130 of the positive current collector 112 of the plurality of battery cells are electrically connected to each other, and the tabs of the negative current collectors 114 of the respective battery cells are electrically connected to each other, thereby realizing the respective battery sheets. The bodies are connected in parallel with each other. By the parallel connection of the plurality of battery cells, the rated voltage of the lithium ion power battery 100 is the rated voltage of each battery cell, and the rated capacity of the lithium ion power battery 100 is the rated capacity of each battery cell. Integer multiple. Taking a battery cell using lithium cobaltate as a positive electrode active material as an example, if the capacity of each battery cell is 4 Ah, and for a practical application, a lithium ion power battery 100 having a rated capacity of 20 Ah is required, and 5 batteries can be used. The monomers are connected in parallel.

Referring to FIG. 5, further, the battery cell may include a battery protection circuit board 140 electrically connected to the tab 130 of the cathode current collector and the tab 130 of the anode current collector. The battery protection circuit board 140 includes The signal acquisition unit 142 and the control unit 144, the signal acquisition unit 142 includes a protection wafer 1420, a voltage detection unit 1422, a current detection unit 1424, and a temperature detection unit 1426. The control unit 144 includes a single chip microcomputer 1440 and a switch unit 1442.

The voltage detecting unit 1422 is electrically connected to the positive electrode tab 102 and the negative electrode tab 104 by the tabs 130 of each of the battery cells. The protection wafer 1420 is electrically connected to the voltage detecting unit 1422, and the voltage of the lithium ion power battery 100 can be detected by the voltage detecting unit 1422. The single chip microcomputer 1440 and the protection chip The 1420 is electrically connected, and can read the voltage value detected by the protection chip 1420, and compare the detected voltage value with a preset voltage value range in the single chip, thereby controlling the switch unit 1442 to open or turn on the charge. Discharge circuit. That is, when the detected voltage value is outside the preset voltage value range, the control switch unit 1442 turns off the charge and discharge circuit of the lithium ion power battery 100 when the detected voltage value is at a preset voltage value. Within the range, the control switch unit 1442 turns on the charge and discharge circuit of the lithium ion power battery 100. The preset voltage value range includes an overcharge voltage set value range and an overdischarge voltage set value range.

The current detecting unit 1424 is electrically connected to the positive electrode tab 102 and the negative electrode tab 104 by the tabs 130 of each of the battery cells, and the current detecting unit 1424 is also electrically connected to the protective wafer 1420. The protection wafer 1420 can detect the current in the lithium ion power battery 100 by the current detecting unit 1424, and the single chip microcomputer 1440 can read the current value detected by the protection wafer 1420, and the detected value is detected. The current value is compared with a range of current values preset in the microcontroller 1440 to control the switching unit 1442 to open or close the charge and discharge circuit. That is, when the current value is greater than or equal to the current set value, the control switch unit 1442 turns off the charge and discharge circuit, and when the duration of the disconnection is greater than the delay set value, the control switch unit 1442 turns on the charging circuit. Wherein, the set current value range includes an overcurrent set current value range and a short circuit current value range.

The temperature detecting unit 1426 is electrically connected to the positive electrode tab 102 and the negative electrode tab 104 by the tabs 130 of each of the battery cells, and the temperature detecting unit 1426 is also electrically connected to the protective wafer 1420. The protection wafer 1420 can detect the operating temperature of the lithium ion power battery 100 by the temperature detecting unit 1426, the single piece The machine 1440 can read the temperature value and turn off the charge and discharge circuit by controlling the switch unit 1442 according to the detected temperature value.

By the arrangement of the battery protection circuit board 140, the cycle life of the lithium ion power battery 100 due to overcharge or overdischarge may be reduced, or the charge and discharge efficiency may be lowered, or may be caused by overheating. Attenuation of battery capacity. Meanwhile, when the lithium ion power battery 100 includes a plurality of battery cells, the battery protection circuit board 140 can effectively protect each battery cell, thereby avoiding the use of the entire lithium ion power battery 100 due to damage of a single battery cell. life.

The method for preparing a battery cell in a lithium ion power battery according to an embodiment of the present invention mainly includes the following steps: step one, providing a positive current collector 112 and a negative current collector 114; and step two, respectively, at the positive current collector 112 and the negative current collector The surface of the 114 is uniformly coated with the positive electrode material layer 122 and the negative electrode material layer 124 to form the positive electrode sheet 102 and the negative electrode sheet 104. In the third step, the first through hole 132 and the second through hole corresponding to the position are formed on the positive electrode sheet 102 and the negative electrode sheet 104. 134; and step four, the positive electrode sheet 102 and the negative electrode sheet 104 are packaged into an outer package structure 108.

In the above step two, the cathode current collector 112 and the anode current collector 114 may 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 and negative set The surface of the fluid 114 is dried and forms a positive electrode material layer 122 and a negative electrode 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 above step three, the method of forming the first through holes 132 and the second through holes 134 may be performed by 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 coating. 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 of equal size can be fixed by the positioning device, and Punch the same position.

When the lithium ion power battery uses an electrolyte or an ionic liquid, the above 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; And (2) injecting an electrolyte between the positive electrode sheet 102 and the negative electrode sheet 104 through the first through hole 132 and the second through hole 134, and encapsulating the positive electrode sheet 102, the negative electrode sheet 104, the separator 106, and the electrolyte in the chamber In the outer package structure 108.

In the above 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 overlaid 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 and the first on the negative electrode 104 The two through holes 134 are aligned as much as possible. When the lithium ion power 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 sequentially laminated a plurality of times 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 above step (2), the electrolyte is injected between the positive electrode tab 102 and the negative electrode tab 104 through the through holes. Since the positive electrode sheet 102 and the negative electrode sheet 104 have a first through hole 132 and a second through hole 134, the electrolyte can quickly flow into the positive electrode sheet 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 power battery. The larger the area of the positive electrode sheet 102 and the negative electrode sheet 104, especially in a large power 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 10 cm or more, preferably 20 cm to 100 cm.

When the lithium ion power battery 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.

Further, the preparation method further includes a step of electrically connecting a battery protection circuit board 140 to the positive electrode tab 102 and the negative electrode tab 104.

When the lithium ion power battery 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 are decomposed between the positive electrode sheet 102 and the negative electrode sheet 104. 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. please. 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

130‧‧‧ Ears

132‧‧‧First through hole

134‧‧‧second through hole

Claims (12)

A lithium ion power battery having a power density of 500 watts/kg or more, comprising at least one battery cell, the at least one battery cell comprising a positive electrode plate and a negative electrode plate stacked and spaced apart, wherein the improvement is 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 being disposed corresponding to one of the first through holes, and an opening ratio of the positive electrode and the negative electrode All are less than 10%. The lithium ion power battery according to claim 1, wherein an area of each of the positive electrode tab and the negative electrode tab in the lithium ion power battery is greater than or equal to 100 square centimeters, respectively. The lithium ion power battery according to claim 1, wherein the positive and negative electrode sheets are disposed in parallel, and in a direction perpendicular to the positive and negative electrode sheets, the mutually corresponding second through holes are located in the first Within the scope of a through hole. The lithium ion power battery of claim 3, wherein the mutually corresponding first through holes are substantially aligned with the axis of the second through holes. The lithium ion power battery of claim 4, wherein a distance between the axes of the two adjacent first through holes and the adjacent two of the second through holes is 1 cm to 50 cm . The lithium ion power battery of claim 1, wherein an area of each of the first through hole and the second through hole is 0.001 square millimeter to 13 square millimeters, respectively. The lithium ion power battery of claim 1, wherein the at least one battery cell further comprises a separator, an electrolyte, and an outer package structure separating the positive electrode sheet from the negative electrode sheet, wherein the outer package structure is the positive electrode sheet , negative electrode sheets, electrolytes and separators Packaged in it. The lithium ion power battery of claim 1, wherein the lithium ion power battery comprises a plurality of battery cells, and the positive electrode sheets of the plurality of battery cells are alternately electrically connected to the negative electrode sheets, thereby realizing the plurality of battery cells Connected in series. The lithium ion power battery according to claim 1, wherein the lithium ion power battery comprises a plurality of battery cells, and the positive electrode sheets of the plurality of battery cells are electrically connected to each other, and the negative electrode sheets of the plurality of battery cells are electrically connected to each other, thereby The plurality of battery cells are realized in parallel with each other. The lithium ion power battery of claim 1, wherein the at least one battery cell comprises a battery protection circuit board electrically connected to the positive electrode tab and the negative electrode tab, the battery protection circuit board comprising a signal acquisition unit and a control unit . A lithium ion power battery having a power density of 500 watts/kg or more, comprising at least one battery cell, the at least one battery cell comprising a plurality of positive electrode sheets and a plurality of negative electrode sheets, the plurality of positive electrode sheets and plural The negative electrode sheets are alternately stacked and spaced apart, and 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, and each of the second through holes has a The first through holes correspond to each other, and the opening ratio of each of the positive electrode sheets and each of the negative electrode sheets is less than 10%. The lithium ion power battery according to claim 11, wherein the plurality of second through holes of each of the negative electrode sheets are disposed in one-to-one correspondence with the plurality of first through holes of the adjacent positive electrode sheets.