Battery capable of preventing internal short circuits

Abstract

A battery capable of preventing internal short circuits. The battery comprises a battery body (100), wherein the battery body (100) comprises a case (101). A negative electrode assembly (110) and a positive electrode assembly (120) are respectively provided at two ends of the case (101). The negative electrode assembly (110) comprises a negative electrode cap end (111), a negative electrode current collector disc (112), and a central tube (113), wherein the negative electrode cap end (111), the negative electrode current collector disc (112), and the central tube (113) are fixed in sequence from bottom to top; the central tube (113) is mounted in the case (101); and the end of the central tube (113) away from the negative electrode current collector disc (112) is separated from the positive electrode assembly (120). By means of arranging the central tube (113) on the negative electrode current collector disc (112), the collapse of electrode sheets is prevented, and good support is also provided for expansion and contraction of a negative electrode. By means of configuring the end of the central tube (113) away from the negative electrode current collector disc (112) not to be in contact with the positive electrode assembly (120), when the battery is in use, the problem of internal short circuits caused by positive and negative electrodes overlapping because the central tube (113) is made of a metallic material can be prevented, thereby being conducive to improving the cycle performance and safety of the battery.

Description

A battery that protects against internal short circuits

[0001] This application claims priority to the patent application filed on October 25, 2024, with China National Intellectual Property Administration, application number 2024226009020, entitled "A Battery for Preventing Internal Short Circuits". Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery that is protected against internal short circuits. Background Technology

[0003] With the rapid development of lithium-ion batteries, the demand for energy density and fast-charging performance is increasing. Developing lithium-ion batteries with high specific energy and long cycle life is essential for further promoting the rapid development of energy storage and utilization. The anode material is an indispensable part of lithium-ion batteries, significantly influencing their overall performance. Silicon has the highest specific capacity among known materials (4200 mAh / g), far exceeding the theoretical capacity of carbon materials (372 mAh / g). During charging and discharging, the silicon anode expands by 300% due to lithium-ion insertion. This expansion generates significant internal stress on the battery casing, while the electrode contracts during desorption, failing to effectively bind the electrode and increasing the gap between cells. Therefore, the expansion and contraction of the silicon anode greatly restricts its long-cycle performance, making it one of the biggest bottlenecks to its practical application.

[0004] There are many existing technologies for batteries that protect against internal short circuits, such as:

[0005] Chinese Patent Publication No. CN220066029U discloses a cylindrical battery, its battery pack, and an electrical device thereof. The cylindrical battery includes a shell, a central tube, a wound electrode assembly, an electrode plate assembly, and a positive electrode post. The top plate of the shell is provided with an electrode post mounting through hole. The central tube is installed inside the shell. The wound electrode assembly is wound on the central tube and spaced apart from the side wall of the shell. The electrode plate assembly includes a positive electrode connecting piece and a negative electrode connecting piece, which are respectively installed at the upper and lower ends of the wound electrode assembly. The positive electrode post is installed in the electrode post mounting through hole and is electrically connected to the positive electrode connecting piece. The positive electrode post is provided with a first positioning part that cooperates with the central tube, and the negative electrode connecting piece is provided with a second positioning part that cooperates with the central tube.

[0006] Therefore, most batteries currently have a central tube inside the battery casing to cope with the expansion and contraction of the electrode plates. By winding the electrode assembly onto the central tube and connecting the two ends of the central tube to the positive electrode connecting piece and the negative electrode connecting piece respectively, the resistance of the central tube itself will restrain the electrode plates when the electrode plates expand. However, due to the corrosiveness of the electrolyte, most central tubes are made of corrosion-resistant metal materials. When the two ends of the central tube made of metal materials are connected to the positive electrode connecting piece and the negative electrode connecting piece respectively, a positive and negative electrode overlap will be formed, resulting in the phenomenon of internal shortness.

[0007] In view of this, we propose a battery that protects against internal short circuits.

[0008] Application content

[0009] The purpose of this application is to provide a battery that protects against internal short circuits, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, this application provides the following technical solution:

[0011] A battery for preventing internal short circuits includes a battery body, which includes a casing. The casing has a negative electrode assembly and a positive electrode assembly at its two ends. The negative electrode assembly includes a negative electrode cap, a negative electrode current collector, and a central tube. The negative electrode cap, the negative electrode current collector, and the central tube are fixed in sequence from bottom to top. The central tube is installed inside the casing, and the end of the central tube away from the negative electrode current collector is separated from the positive electrode assembly.

[0012] As a further aspect of this application: one end of the outer casing is a closed end, and the other end of the outer casing is an open end; a through groove is provided at the center of the closed end of the outer casing, and the positive electrode assembly includes a positive terminal, which is installed on the closed end of the outer casing through the through groove.

[0013] As a further aspect of this application, the positive electrode assembly also includes a positive electrode current collector installed in the inner cavity of the housing, with one end of the positive terminal welded and fixed to one side of the positive electrode current collector.

[0014] As a further aspect of this application: a second sealant is provided between the positive terminal and the inner cavity of the outer casing, a first sealant is provided between the positive terminal and the through groove of the outer casing, and an insulating gasket is provided between the positive terminal and the outer side of the outer casing.

[0015] As a further aspect of this application: the opening end of the outer casing and the negative electrode cover end are sealed and fixed by laser welding.

[0016] As a further aspect of this application: a wound electrode assembly is provided between the negative electrode assembly and the positive electrode assembly, and the two ends of the wound electrode assembly are welded and fixed to the positive electrode current collector and the negative electrode current collector, respectively.

[0017] As a further embodiment of this application: the wound pole assembly is arranged in a ring around the center tube.

[0018] As a further aspect of this application: the length of the central tube is the length of the negative electrode sheet plus 1 mm.

[0019] As a further embodiment of this application, the central tube is spiral, mesh, or cylindrical in shape.

[0020] As a further aspect of this application, both the central tube and the outer shell are made of shape memory alloy.

[0021] Compared with the prior art, the beneficial effects of this application are as follows:

[0022] 1. In this battery designed to prevent internal short circuits, a central tube is installed on the negative electrode current collector. The addition of the central tube prevents the electrode from collapsing and provides good support for the expansion and contraction of the negative electrode.

[0023] 2. In this battery designed to prevent internal short circuits, by setting the end of the central tube away from the negative current collector to be in no contact with the positive electrode assembly, the positive and negative electrodes will not come into contact during battery use due to the central tube being made of metal, thus preventing internal short circuits and improving the cycle life and safety of the battery. Attached Figure Description

[0024] Figure 1 is a diagram of the overall structure of this scheme;

[0025] Figure 2 is an overall sectional view of this scheme;

[0026] Figure 3 is the second overall sectional view of this scheme.

[0027] The labels in the diagram represent the following: 100, battery body; 101, outer casing; 110, negative electrode assembly; 111, negative electrode cap; 112, negative electrode current collector; 113, center tube; 120, positive electrode assembly; 121, positive terminal; 122, insulating gasket; 123, first sealant; 124, second sealant; 125, positive electrode current collector. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] Example

[0030] Currently, most batteries have a central tube 113 inside the battery casing to cope with the expansion and contraction of the electrode. By winding the electrode assembly onto the central tube 113, and then connecting the two ends of the central tube 113 to the positive electrode connecting piece and the negative electrode connecting piece respectively, the resistance of the central tube 113 itself will bind the electrode when the electrode expands. However, due to the corrosiveness of the electrolyte, the central tube 113 is mostly made of corrosion-resistant metal material. When the two ends of the central tube 113 made of metal material are connected to the positive electrode connecting piece and the negative electrode connecting piece respectively, the positive and negative electrodes will overlap, resulting in the phenomenon of internal shortness.

[0031] Therefore, referring to Figures 1 and 2, the purpose of this embodiment is to provide a battery that prevents internal short circuits, including a battery body 100. The battery body 100 includes a shell 101. The two ends of the shell 101 are respectively provided with a negative electrode assembly 110 and a positive electrode assembly 120. The negative electrode assembly 110 includes a negative electrode cap end 111, a negative electrode current collector 112, and a central tube 113. Considering that the central tube 113 cannot be connected to the positive electrode connecting piece and the negative electrode connecting piece, thereby forming a positive and negative electrode overlap and causing an internal short circuit, the negative electrode cap end 111, the negative electrode current collector 112, and the central tube 113 are fixed sequentially from bottom to top. The central tube 113 is installed inside the shell 101, and the end of the central tube 113 away from the negative electrode current collector 112 is separated from the positive electrode assembly 120.

[0032] The improvement of this embodiment lies in the following: by setting a central tube 113 on the negative electrode current collector 112, the addition of the central tube 113 avoids the collapse of the electrode sheet, and at the same time, it plays a good supporting role for the expansion and contraction of the negative electrode; by setting the end of the central tube 113 away from the negative electrode current collector 112 to not contact the positive electrode assembly 120, the positive and negative electrodes will not overlap and cause internal shorting problems when the battery is in use because the central tube 113 itself is made of metal, which is beneficial to improving the cycle performance and safety of the battery.

[0033] Please refer to Figure 3. Considering the convenience of installing the positive terminal 121, one end of the housing 101 is a closed end. A through groove is provided at the center of the closed end of the housing 101. The positive terminal assembly 120 includes the positive terminal 121. The positive terminal 121 is installed on the closed end of the housing 101 through the through groove, thereby installing the positive terminal 121 on the housing 101.

[0034] The positive electrode assembly 120 also includes a positive electrode current collector 125 installed in the inner cavity of the housing 101. Considering the fixation of the positive electrode current collector 125 and to avoid the positive electrode current collector 125 from contacting the housing 101 and causing the surface of the housing 101 to become charged, one end of the positive terminal 121 is welded and fixed to one side of the positive electrode current collector 125.

[0035] Meanwhile, to prevent the positive terminal 121 from contacting the outer casing 101 and causing the surface of the outer casing 101 to become charged, a second sealant 124 is provided between the positive terminal 121 and the inner cavity of the outer casing 101, a first sealant 123 is provided between the positive terminal 121 and the through groove of the outer casing 101, and an insulating gasket 122 is provided between the positive terminal 121 and the outer side of the outer casing 101. The sealant and the insulating gasket 122 prevent the positive terminal 121 and the outer casing 101 from contacting each other, thus eliminating the possibility of the surface of the outer casing 101 becoming charged.

[0036] The end of the outer casing 101 relative to the closed end is an open end. Considering the sealing of the battery body 100, the open end of the outer casing 101 and the negative electrode cover end 111 are sealed and fixed by laser welding. With the help of sealant, insulating gasket 122 and positive terminal 121, the outer casing 101 is sealed.

[0037] A wound electrode assembly is also provided between the negative electrode assembly 110 and the positive electrode assembly 120. The two ends of the wound electrode assembly are welded and fixed to the positive electrode current collector 125 and the negative electrode current collector 112, respectively. Through welding and fixing, the connection between the wound electrode assembly, the positive electrode current collector 125 and the negative electrode current collector 112 is more secure. This helps to enhance the stability of the internal structure of the battery and prevent the internal components from loosening or being damaged due to expansion and contraction during charging and discharging.

[0038] Since the winding pole assembly itself is wound around the winding needle, the winding needle is pulled out after the winding pole assembly is completed. Therefore, the outer diameter of the winding needle is the same as that of the central tube 113, which is equivalent to the winding pole assembly being arranged in a circle with the central tube 113 as the center.

[0039] Considering the expansion and contraction phenomenon of the negative electrode during charging and discharging, one side of the negative electrode needs to be completely in contact with the central tube 113 in order to suppress the expansion of the negative electrode. Therefore, the length of the central tube 113 is the length of the negative electrode plus 1mm to support the expansion of the negative electrode. At the same time, the central tube 113 does not contact the positive current collector 125 to avoid short circuit.

[0040] Considering that battery design needs to be tailored to different usage scenarios, the shape of the central tube 113 can be spiral, mesh, or cylindrical. When the central tube 113 is spiral, its surface area can be increased, thereby providing more ion channels, which helps to improve the battery's charge and discharge rate and energy density, reduce the battery's internal resistance, and improve the battery's response speed and efficiency. When the central tube 113 is mesh, it can provide more heat dissipation channels, which helps to dissipate the heat generated by the battery during charging and discharging in a timely manner, preventing the battery from overheating and being damaged. When the central tube 113 is cylindrical, it can provide stable support for the battery's interior, which helps to maintain the flatness and positional accuracy of the electrode plates and separator.

[0041] Due to the expansion and contraction of the negative electrode during charging and discharging, the materials of the central tube 113 and the outer shell 101 must possess excellent elastic recovery, deformation resistance, durability, and corrosion resistance. Therefore, both the central tube 113 and the outer shell 101 are made of shape memory alloy. Shape memory alloy has a unique shape memory effect, meaning that after deformation under external force, it can recover to its original shape under certain conditions. This characteristic allows shape memory alloy to adapt well to the expansion and contraction of the negative electrode, maintaining the stability and integrity of the battery's internal structure. Furthermore, shape memory alloy has excellent elasticity and recovery, capable of withstanding large deformations without cracking or permanent deformation. It also typically possesses good electrical conductivity, thermal conductivity, mechanical strength, and durability. In this embodiment, the shape memory alloy includes, but is not limited to, TiNi-based shape memory alloys, copper-based shape memory alloys, and iron-based shape memory alloys.

[0042] In summary, the working principle of this solution is as follows:

[0043] During battery charging, the negative electrode expands, causing deformation of the central tube 113 and the outer casing 101. Since the central tube 113 and the outer casing 101 are made of shape memory alloy, their metallic properties inhibit the expansion of the negative electrode, thus supporting its expansion and binding it, preventing the cell gap from widening. Similarly, during battery discharging, the negative electrode contracts, also bound by the central tube 113 and the outer casing 101. Simultaneously, the central tube 113 is fixed only to the negative current collector 112, ensuring that the positive and negative electrodes do not connect due to the central tube 113 during charging or discharging, preventing internal shorting. Furthermore, the metallic material of the central tube 113 provides excellent heat conduction, improving cell safety and cycle performance.

[0044] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0045] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A battery for preventing internal short circuits, comprising a battery body (100), the battery body (100) including a casing (101), wherein a negative electrode assembly (110) and a positive electrode assembly (120) are respectively provided at both ends of the casing (101), characterized in that: The negative electrode assembly (110) includes a negative electrode cap (111), a negative electrode current collector (112), and a central tube (113), wherein the negative electrode cap (111), the negative electrode current collector (112), and the central tube (113) are fixed in sequence from bottom to top; the central tube (113) is installed inside the outer shell (101), and the end of the central tube (113) away from the negative electrode current collector (112) is separated from the positive electrode assembly (120).

2. The battery for preventing internal short circuits according to claim 1, characterized in that: One end of the outer shell (101) is a closed end, and the other end of the outer shell (101) is an open end; a through groove is provided at the center of the closed end of the outer shell (101), and the positive electrode assembly (120) includes a positive terminal (121), which is installed on the closed end of the outer shell (101) through the through groove.

3. The battery for preventing internal short circuits according to claim 2, characterized in that: The positive electrode assembly (120) also includes a positive electrode current collector (125) installed in the inner cavity of the housing (101), and one end of the positive electrode terminal (121) is welded and fixed to one side of the positive electrode current collector (125).

4. The battery for preventing internal short circuits according to claim 2, characterized in that: A second sealant (124) is provided between the positive terminal (121) and the inner cavity of the outer shell (101), a first sealant (123) is provided between the positive terminal (121) and the through groove of the outer shell (101), and an insulating gasket (122) is provided between the positive terminal (121) and the outer side of the outer shell (101).

5. The battery for preventing internal short circuits according to claim 1, characterized in that: The opening end of the outer shell (101) and the negative electrode cover end (111) are sealed and fixed by laser welding.

6. The battery for preventing internal short circuits according to claim 1, characterized in that: A wound electrode assembly is provided between the negative electrode assembly (110) and the positive electrode assembly (120), and the two ends of the wound electrode assembly are welded and fixed to the positive electrode current collector (125) and the negative electrode current collector (112), respectively.

7. The battery for preventing internal short circuits according to claim 6, characterized in that: The wound pole group is arranged in a circle with the central tube (113) as the center.

8. The battery for preventing internal short circuits according to claim 1, characterized in that: The length of the central tube (113) is the length of the negative electrode sheet plus 1 mm.

9. The battery for preventing internal short circuits according to claim 1, characterized in that: The central tube (113) is spiral, mesh, or cylindrical in shape.

10. The battery for preventing internal short circuits according to claim 1, characterized in that: Both the central tube (113) and the outer shell (101) are made of shape memory alloy.

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