Safe lithium battery

Abstract

The utility model provides a safe lithium battery which comprises a shell, a battery cell, positive tabs and negative tabs, the battery cell is located in the shell and comprises multiple positive plates, multiple diaphragms and multiple negative plates, the multiple positive plates and the multiple negative plates are alternately stacked, the adjacent positive plates and negative plates are separately arranged through the diaphragms, and the positive tabs and the negative tabs are arranged in the shell. And forming the laminated cell structure. Each positive plate comprises a PET (Polyethylene Terephthalate) composite aluminum foil and positive material layers formed on two side surfaces of the PET composite aluminum foil, and one end of each of the plurality of stacked positive plates is welded and fixedly connected to the positive lug. Each negative plate comprises a PET composite copper foil and negative material layers formed on two side surfaces of the PET composite copper foil, and one end of each of the plurality of stacked negative plates is welded and fixedly connected to the negative lug.

Description

Technical Field

[0001] The present disclosure relates to the technical field of batteries, and in particular, to a safe lithium battery. Background Art

[0002] A lithium-ion battery is a rechargeable battery that mainly operates by the movement of lithium ions between the positive electrode and the negative electrode. During the charge and discharge process, lithium ions are inserted and extracted back and forth between the positive and negative electrodes. Specifically, during charging, lithium ions are extracted from the positive electrode, move through the electrolyte, and are inserted into the negative electrode, making the negative electrode in a lithium-rich state; during discharging, the process is reversed. Lithium-ion batteries have advantages such as long cycle life and environmental friendliness, and are a widely used power supply technology.

[0003] For traditional lithium batteries, such as the patent document CN115172893A, the negative current collector uses copper foil and the positive current collector uses aluminum foil. When the battery is subjected to external force extrusion or puncture, the battery is prone to short-circuit situations, causing a large amount of heat to be generated by the metal of the current collector at the moment of short circuit, leading to thermal runaway of the battery and resulting in a relatively low safety problem of the battery. Summary of the Utility Model

[0004] The purpose of the present disclosure is to overcome the deficiencies in the prior art and provide a safe lithium battery with relatively high safety.

[0005] The purpose of the present disclosure is achieved through the following technical solutions:

[0006] A safe lithium battery includes a housing, an electric core, a positive electrode tab, and a negative electrode tab. The electric core is located inside the housing. The electric core includes a positive electrode plate, a separator, and a negative electrode plate. The number of the positive electrode plates and the number of the negative electrode plates are both multiple. The multiple positive electrode plates and the multiple negative electrode plates are alternately stacked, and adjacent positive electrode plates and negative electrode plates are separated by the separator to form a stacked electric core structure.

[0007] Each positive electrode plate includes a PET composite aluminum foil and positive electrode material layers formed on both side surfaces of the PET composite aluminum foil. One end of the multiple stacked positive electrode plates is fixedly connected by welding to the positive electrode tab.

[0008] Each negative electrode plate includes a PET composite copper foil and negative electrode material layers formed on both side surfaces of the PET composite copper foil. One end of the multiple stacked negative electrode plates is fixedly connected by welding to the negative electrode tab.

[0009] In one embodiment, the PET composite aluminum foil includes a positive electrode PET film and metal coatings compounded on both surfaces in the thickness direction of the positive electrode PET film layer. Two layers of the positive electrode material layers are respectively formed on the outer surfaces of the corresponding metal coatings.

[0010] In one embodiment, the PET composite copper foil includes a negative PET film and conductive layers compounded on two surfaces in the thickness direction of the negative PET film layer, and two layers of the negative electrode material layers are respectively formed on the outer surfaces of the corresponding conductive layers.

[0011] In one embodiment, each positive electrode sheet further includes two aluminum foil strips. The first ends of the two aluminum foil strips are respectively connected to two outer surfaces in the thickness direction of the PET composite aluminum foil, and the second ends of the two aluminum foil strips both extend outward and are stacked on the PET composite aluminum foil and connected to the positive electrode tab.

[0012] In one embodiment, a positive electrode tab foil is formed at the second end of each aluminum foil strip, and the positive electrode tab foils of the aluminum foil strips of multiple positive electrode sheets are stacked and connected to the positive electrode tab.

[0013] In one embodiment, each negative electrode sheet further includes two copper foil strips. The first ends of the two copper foil strips are respectively connected to two outer surfaces in the thickness direction of the PET composite copper foil, and the second ends of the two copper foil strips both extend outward and are stacked on the PET composite copper foil and connected to the negative electrode tab.

[0014] In one embodiment, a negative electrode tab foil is formed at the second end of each copper foil strip, and the negative electrode tab foils of the copper foil strips of multiple negative electrode sheets are stacked and connected to the negative electrode tab.

[0015] In one embodiment, the separator is bent and sequentially penetrates through any adjacent positive electrode sheet and negative electrode sheet along the stacking direction of the stacked cell structure.

[0016] Compared with the prior art, the present disclosure has at least the following advantages:

[0017] 1. Using composite aluminum foil and composite copper foil as the base materials of the positive and negative electrode sheets can improve the strength and stability of the safe lithium battery, thereby enhancing the safety of the safe lithium battery; at the same time, the tensile strength of the composite aluminum foil and composite copper foil is higher than that of traditional copper foil and aluminum foil, which can meet the requirements of high-speed coating and improve the quality and performance of the electrode sheets.

[0018] 2. Using composite aluminum foil and composite copper foil as the base materials of the positive and negative electrode sheets makes the positive and negative electrode sheets thinner and lighter, thereby reducing the weight of the safe lithium battery and improving the volume energy density, weight energy density and safety of the safe lithium battery. Description of the Drawings

[0019] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the accompanying drawings required for the embodiments. It should be understood that the following drawings only show certain embodiments of the present disclosure, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0020] Figure 1 Schematic diagram of the outer shell of a safety-type lithium battery in one embodiment;

[0021] Figure 2 Cross-sectional view of a safety-type lithium battery in one embodiment;

[0022] Figure 3 For Figure 2 Cross-sectional view of the positive electrode plate of the safety-type lithium battery shown;

[0023] Figure 4 For Figure 2 Schematic diagram of the unfolded structure of the positive electrode plate of the safety-type lithium battery shown in another state;

[0024] Figure 5 For Figure 2 Cross-sectional view of the negative electrode plate of the safety-type lithium battery shown;

[0025] Figure 6 For Figure 2 Schematic diagram of the unfolded structure of the negative electrode plate of the safety-type lithium battery shown in another state;

[0026] Figure 7 For Figure 1 Schematic diagram of the laminated structure of the positive electrode plate of the safety-type lithium battery shown;

[0027] Figure 8 For Figure 1 Schematic diagram of the laminated structure of the negative electrode plate of the safety-type lithium battery shown. Detailed implementation manners

[0028] To facilitate the understanding of the present disclosure, the following will describe the present disclosure more comprehensively with reference to the relevant accompanying drawings. The preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure content of the present disclosure understood more thoroughly and comprehensively.

[0029] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this disclosure pertains. The terms used herein in the specification of this disclosure are only for the purpose of describing specific implementations and are not intended to limit this disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] To better understand the technical solutions and beneficial effects of this disclosure, the following further describes this disclosure in detail with specific embodiments:

[0032] Please refer to Figures 1 to 8 , which is a safety-type lithium battery 10 according to an embodiment of the present utility model, including a housing 100, a battery cell 200, a positive tab 300 and a negative tab 400. The battery cell 200 is located inside the housing 100. The battery cell 200 includes a positive electrode plate 210, a separator 220 and a negative electrode plate 230. The number of positive electrode plates 210 and the number of negative electrode plates 230 are both multiple. The multiple positive electrode plates 210 and the multiple negative electrode plates 230 are alternately stacked. The adjacent positive electrode plate 210 and negative electrode plate 230 are separated by the separator 220 to form a stacked battery cell structure. Each positive electrode plate 210 includes a PET composite aluminum foil 211 and a positive electrode material layer (not shown in the figure) formed on both sides of the PET composite aluminum foil 211. One end of the multiple stacked positive electrode plates 210 is fixedly connected to the positive tab 300 by welding. Each negative electrode plate 230 includes a PET composite copper foil 231 and a negative electrode material layer (not shown in the figure) formed on both sides of the PET composite copper foil 231. One end of the multiple stacked negative electrode plates 230 is fixedly connected to the negative tab 400 by welding.

[0033] In this embodiment, using the PET composite aluminum foil 211 and the PET composite copper foil 231 as the base materials of the positive electrode plate 210 and the negative electrode plate 230 can improve the strength and stability of the safety-type lithium battery 10, thereby improving the safety of the safety-type lithium battery 10.

[0034] Furthermore, the tensile strength of the PET composite aluminum foil 211 and the PET composite copper foil 231 is higher than that of traditional copper foils and aluminum foils, which can meet the requirements of high-speed coating and improve the quality and performance of the electrode sheets.

[0035] Furthermore, using PET composite aluminum foil 211 and PET composite copper foil 231 as the substrates of the positive electrode sheet 210 and the negative electrode sheet 230 makes the positive electrode sheet 210 and the negative electrode sheet 230 thinner and lighter, thereby reducing the weight of the safety-type lithium battery 10 and improving the volume energy density, weight energy density, and safety of the safety-type lithium battery 10.

[0036] As Figure 3 and Figure 4 shown, in one embodiment, the PET composite aluminum foil 211 includes a positive electrode PET film layer 2111 and metal coatings 2112 compounded on two surfaces in the thickness direction of the positive electrode PET film layer 2111, and two layers of positive electrode material layers are respectively formed on the outer surfaces of the corresponding metal coatings 2112. Specifically, in this embodiment, the PET composite aluminum foil 211 has a "sandwich" structure, with the inner layer being the PET film layer and the two sides being the metal coatings 2112. It can be understood that the thickness of the PET composite aluminum foil 211 is the thickness of the positive electrode PET film + the thickness of the metal coating 2112. Thus, the PET composite aluminum foil 211 is thinner and lighter than the traditional aluminum foil, that is, the positive electrode sheet 210 is thinner and lighter. Thereby, the total thickness of the safety-type lithium battery 10 is reduced, and the volume energy density of the safety-type lithium battery 10 is improved. Further, the composite aluminum foil has a greater tensile strength and can meet the requirements of high-speed coating.

[0037] As Figure 5 and Figure 6 shown, in one embodiment, the PET composite copper foil 231 includes a negative electrode PET film layer 2311 and conductive layers 2312 compounded on two surfaces in the thickness direction of the negative electrode PET film layer 2311, and two layers of negative electrode material layers are respectively formed on the outer surfaces of the corresponding conductive layers 2312. In this embodiment, the PET composite copper foil 231 has a "sandwich" structure, with the inner layer being the PET film layer and the two sides being the conductive layers 2312. It can be understood that the conductive layer of the PET composite copper foil 231 has a smaller thickness than the traditional copper foil. Thus, when punctured, the burrs generated by the conductive layer 2312 are relatively small, and it is not easy to occur puncture short-circuit phenomenon, improving the safety of the safety-type lithium battery 10.

[0038] It should be noted that the positive electrode PET film layer 2111 and the negative electrode PET film layer 2311 will shrink at high temperatures above 150°C. Thus, it can cut off the current circuit before the thermal runaway of the safety-type lithium battery 10 and will not burn explosively at high temperatures due to short circuit, improving the safety performance of the safety-type lithium battery 10.

[0039] As Figure 4As shown, in one embodiment, each positive electrode sheet 210 further includes two aluminum foil strips 213. The first ends of the two aluminum foil strips 213 are respectively connected to two outer surfaces in the thickness direction of the PET composite aluminum foil 211, and the second ends of the two aluminum foil strips 213 both extend outward and are stacked on the PET composite aluminum foil 211 and connected to the positive electrode tab 300. It can be understood that the first end of the aluminum foil strip 213 is directly attached to the positive electrode sheet 210, and the positive electrode tab 300 is transferred through the aluminum foil strip 213, so that the cross-sectional thickness of the battery cell 200 is smaller than that of the traditional battery cell structure, improving the energy density of the battery cell 200.

[0040] Furthermore, the structure and connection relationship of the aluminum foil strip 213 are simple and can adapt to the production conditions of the electrode sheet.

[0041] As Figure 3 、and Figure 4 and Figure 7 As shown, in one embodiment, a positive electrode tab foil 2131 is formed at the second end of each aluminum foil strip 2131, and the positive electrode tab foils 2131 of the aluminum foil strips 213 of multiple positive electrode sheets 210 are stacked and connected to the positive electrode tab 300. Specifically, in this embodiment, the positive electrode tab foil 2131 connects the positive electrode tab 300 and the PET composite aluminum foil 211, so that the welding part of the positive electrode tab 300 and the positive electrode sheet 210 is located outside the PET composite aluminum foil 211. In this way, the positive electrode tab 300 does not need to be welded to the positive electrode PET film layer 2111, reducing the welding difficulty.

[0042] As Figure 6 As shown, in one embodiment, each negative electrode sheet 230 further includes two copper foil strips 233. The first ends of the two copper foil strips 233 are respectively connected to two outer surfaces in the thickness direction of the PET composite copper foil 231, and the second ends of the two copper foil strips 233 both extend outward and are stacked on the PET composite copper foil 231 and connected to the negative electrode tab 400. It can be understood that the first end of the copper foil strip 233 is attached to the negative electrode material layer of the negative electrode sheet 230, and the second end is connected to the negative electrode tab 400, so that the cross-sectional thickness of the battery cell 200 is smaller than that of the traditional battery cell structure, improving the energy density of the battery cell 200.

[0043] As Figure 5 、 Figure 6 and Figure 8As shown, in one embodiment, a negative tab foil 2331 is formed at the second end of each copper foil strip 233. The negative tab foils 2331 of the copper foil strips 233 of multiple negative plates 230 are stacked and connected to the negative tab 400. The positive tab foil 2131 and the negative tab foil 2331 are arranged alternately. It can be understood that the negative tab foil 2331 is formed on the copper foil strip 233. One end of the negative tab foil 2331 is attached to the negative electrode material layer of the negative plate 230, and the other end of the negative tab foil 2331 is located outside the negative plate 230, so that the welding part between the negative plate 230 and the negative tab 400 is located outside the PET composite copper foil 231, avoiding the welding of the negative tab 400 to the negative PET film layer 2311 of the PET composite copper foil 231 and reducing the welding difficulty.

[0044] It should be noted that, in one embodiment, when the aluminum foil strip 213 and the copper foil strip 233 face the same direction, the aluminum foil strip 213 and the copper foil strip 233 are arranged alternately and insulated from each other through the separator 200 between the positive plate 300 and the negative plate 400 to avoid electrical contact.

[0045] As Figure 2 shown, in one embodiment, the separator 220 is bent along the stacking direction of the stacked cell structure and sequentially penetrates through any adjacent positive plate 210 and negative plate 230 to form a stacked cell structure. Specifically, in this embodiment, the preparation steps of the stacked cell structure are as follows:

[0046] Place the separator 220 on the table to form a bottom separator 220; place a first electrode plate on the bottom separator 220, and this first electrode plate is the first bottom electrode plate; wind the remaining separator 220 to form a first separator layer covering the first electrode plate.

[0047] Place a second electrode plate above the first separator layer, and the polarity of the second electrode plate is opposite to that of the first electrode plate; wind the remaining separator 220 to form a second separator layer covering the second electrode plate.

[0048] Place a first electrode plate above the second separator layer, and wind the remaining separator 220 to form a first separator layer covering the first electrode plate.

[0049] Repeat the above steps N times to form a stacked cell structure, where N is a positive integer greater than or equal to 1.

[0050] The stacked cell structure formed in this way increases the contact area and precision between the separator 220 and the electrode plate, ensuring the stability of the cell structure; at the same time, it optimizes the heat conduction path inside the safety lithium battery 10, helps local heat dissipation, reduces the risk of thermal runaway, and improves the safety of the safety lithium battery 10.

[0051] Furthermore, the laminated battery cell structure can prevent the direct contact between the positive and negative electrode plates 230, prevent the occurrence of internal short circuits in the safety lithium battery 10, and improve the safety of the safety lithium battery 10.

[0052] Compared with the prior art, the present disclosure has at least the following advantages:

[0053] 1. Using composite aluminum foil and composite copper foil as the substrates of the positive and negative electrode plates can improve the strength and stability of the safety lithium battery, thereby improving the safety of the safety lithium battery; at the same time, the tensile strength of the composite aluminum foil and composite copper foil is higher than that of traditional copper foil and aluminum foil, which can meet the requirements of high-speed coating and improve the quality and performance of the electrode plates.

[0054] 2. Using composite aluminum foil and composite copper foil as the substrates of the positive and negative electrode plates makes the positive and negative electrode plates thinner and lighter, thereby reducing the weight of the safety lithium battery and improving the volume energy density, weight energy density and safety of the safety lithium battery.

[0055] The above-described embodiments merely represent several implementation manners of the present disclosure, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the disclosed patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A safety lithium battery, comprising a shell, a battery cell, a positive electrode ear and a negative electrode ear, wherein the battery cell is located in the shell, and the battery cell comprises a positive electrode sheet, a separator and a negative electrode sheet, wherein the number of the positive electrode sheets and the number of the negative electrode sheets are both multiple, and the multiple positive electrode sheets and the multiple negative electrode sheets are alternately stacked, and the adjacent positive electrode sheets and the negative electrode sheets are separated by the separator to form a laminated battery cell structure, characterized in that: Each of the positive electrode sheets comprises a PET composite aluminum foil and a positive electrode material layer formed on both sides of the PET composite aluminum foil, and one end of the plurality of stacked positive electrode sheets is welded and fixedly connected to the positive electrode ear; Each of the negative electrode sheets comprises a PET composite copper foil and a negative electrode material layer formed on both sides of the PET composite copper foil. One end of a plurality of stacked negative electrode sheets is welded and fixedly connected to the negative electrode ear.

2. The safety lithium battery according to claim 1, characterized in that: The PET composite aluminum foil comprises a positive electrode PET film and a metal coating composited on both surfaces of the positive electrode PET film layer in a thickness direction, and the two positive electrode material layers are respectively formed on the outer surfaces of the corresponding metal coatings.

3. The safety lithium battery according to claim 1, characterized in that: The PET composite copper foil comprises a negative electrode PET film and a conductive layer composited on both surfaces of the negative electrode PET film layer in a thickness direction, and the two negative electrode material layers are respectively formed on the outer surfaces of the corresponding conductive layers.

4. The safety lithium battery according to claim 1, characterized in that: Each of the positive electrode sheets also includes two aluminum foil strips, the first ends of the two aluminum foil strips are respectively connected to the two outer surfaces of the PET composite aluminum foil in the thickness direction, and the second ends of the two aluminum foil strips are extended to the outside of the PET composite aluminum foil and are connected to the positive electrode ear.

5. The safety lithium battery according to claim 4, characterized in that: A positive electrode tab foil is formed on the second end of each of the aluminum foil strips, and the positive electrode tab foils of the aluminum foil strips of the plurality of positive electrode sheets are stacked and connected to the positive electrode tabs.

6. The safety lithium battery according to claim 1, characterized in that: Each of the negative electrode sheets also includes two copper foil strips, the first ends of the two copper foil strips are respectively connected to the two outer surfaces in the thickness direction of the PET composite copper foil, and the second ends of the two copper foil strips are extended to the outside of the PET composite copper foil and are connected to the negative electrode ears.

7. The safety lithium battery according to claim 6, characterized in that: A negative electrode tab foil is formed on the second end of each of the copper foil strips, and the negative electrode tab foils of the copper foil strips of a plurality of negative electrode sheets are stacked and connected to the negative electrode tabs.

8. The safe lithium battery according to claim 1, characterized in that: The diaphragm is bent and sequentially penetrated through any adjacent positive electrode sheets and negative electrode sheets along the stacking direction of the laminated battery core structure.

Images