Battery capable of preventing internal short circuit

Abstract

The utility model relates to the technical field of batteries, in particular to a battery capable of preventing internal short circuit, which comprises a battery body, the battery body comprises a shell, a negative electrode assembly and a positive electrode assembly are respectively arranged at two ends of the shell, and the negative electrode assembly comprises a negative electrode cover end, a negative electrode collector plate and a central tube, the cathode cover end, the cathode collector plate and the central tube are sequentially fixed from bottom to top; the central tube is mounted in the shell; one end, far away from the cathode collector plate, of the central tube is separated from the anode assembly. When the lithium ion battery is used, the central tube is arranged on the cathode collector plate, so that the collapse of the pole piece is avoided, and meanwhile, the expansion and the shrinkage of the cathode are well supported; the end, far away from the negative collector plate, of the central tube is not in contact with the positive electrode assembly, so that the problems of positive and negative electrode lap joint and internal short caused by the fact that the central tube is made of a metal material when the battery is used are solved, and the cyclicity and the safety of the battery performance are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery that is resistant to internal short circuits. Background Art

[0002] With the rapid development of lithium-ion batteries, people have increasingly higher demands for their energy density and fast charging performance. Developing lithium-ion batteries with high specific energy and long cycle life is a necessary condition for further promoting the rapid development of energy storage and utilization. The negative electrode material is an indispensable part of lithium-ion batteries and greatly affects their overall performance. Silicon has the highest specific capacity (4200mAh / g) among currently known materials, far exceeding the theoretical capacity of carbon materials (372mAh / g). During the charge and discharge process, the silicon negative electrode expands by 300% due to the insertion of lithium ions. The large internal stress during expansion exerts a huge force on the battery casing, and the electrode shrinks during the release process, failing to properly restrain the electrode, resulting in an increase in the gap between the battery cells. Therefore, the expansion and contraction of the silicon negative electrode greatly restricts its long-cycle performance and is one of the biggest bottlenecks in its practical application.

[0003] There are many existing technologies for batteries that prevent internal short circuits, such as:

[0004] Chinese patent publication number CN220066029U discloses a cylindrical battery, a battery pack thereof, and an electrical device. The cylindrical battery includes a shell, a center tube, a wound electrode group, a pole piece assembly, and a positive electrode column. The top plate of the shell is provided with a pole column mounting through hole. The center tube is installed in the shell. The wound electrode group is wound on the center tube and is spaced from the side wall of the shell. The pole piece assembly includes a positive electrode connecting piece and a negative electrode connecting piece. The positive electrode connecting piece and the negative electrode connecting piece are respectively installed at the upper and lower ends of the wound electrode group. The positive electrode column is installed in the pole column mounting through hole and is electrically connected to the positive electrode connecting piece. The positive electrode column is provided with a first positioning portion that cooperates with the center tube, and the negative electrode connecting piece is provided with a second positioning portion that cooperates with the center tube.

[0005] It can be seen that most batteries currently have a central tube inside the battery casing to deal with the expansion and contraction of the electrode sheets. By winding the wound electrode group on the central tube and then connecting the two ends of the central tube to the positive electrode connecting piece and the negative electrode connecting piece respectively, when the electrode sheet expands, the resistance of the central tube itself will restrain the electrode sheet. 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, the positive and negative electrodes will overlap, causing internal short circuit.

[0006] In view of this, we propose a battery that is resistant to internal short circuit. Utility Model Content

[0007] The purpose of the present utility model is to provide a battery that prevents internal short circuits, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above objectives, the present invention provides the following technical solutions:

[0009] A battery that prevents internal short circuits includes a battery body, the battery body including an outer shell, a negative electrode assembly and a positive electrode assembly being respectively provided at both ends of the outer shell, the negative electrode assembly including a negative electrode cover, a negative electrode current collecting plate and a central tube, wherein the negative electrode cover, the negative electrode current collecting plate and the central tube are fixed in sequence from bottom to top; the central tube is installed in the outer shell, and the end of the central tube away from the negative electrode current collecting plate is separated from the positive electrode assembly.

[0010] As a further solution of the present invention: one end of the shell is a closed end, and the other end of the shell is an open end; a through groove is provided at the center of the closed end of the shell, and the positive electrode assembly includes a positive terminal, and the positive terminal is installed on the closed end of the shell through the through groove.

[0011] As a further solution of the present invention: the positive electrode assembly further includes a positive electrode current collecting disk installed in the inner cavity of the shell, and one end of the positive electrode terminal is welded and fixed to one side of the positive electrode current collecting disk.

[0012] As a further solution of the present invention: a second sealant is provided between the positive terminal and the inner cavity of the shell, a first sealant is provided between the positive terminal and the through groove of the shell, and an insulating gasket is provided between the positive terminal and the outer side of the shell.

[0013] As a further solution of the present invention: the opening end of the shell and the negative electrode cover end are sealed and fixed by laser welding.

[0014] As a further solution of the present invention: a wound electrode group is provided between the negative electrode assembly and the positive electrode assembly, and two ends of the wound electrode group are respectively welded and fixed to the positive electrode current collecting disc and the negative electrode current collecting disc.

[0015] As a further solution of the present invention: the wound pole group is arranged in a circle with the central tube as the center.

[0016] As a further solution of the present invention: the length of the central tube is the length of the negative electrode sheet plus 1 mm.

[0017] As a further solution of the present invention: the shape of the central tube is spiral, mesh or barrel.

[0018] As a further solution of the present invention: the central tube and the outer shell are both made of memory alloy material.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. In the battery that prevents internal short circuit, a central tube is provided on the negative electrode current collecting disk. The addition of the central tube avoids the collapse of the electrode sheet and at the same time provides good support for the expansion and contraction of the negative electrode.

[0021] 2. In the battery that prevents internal short circuit, by setting the end of the central tube away from the negative electrode current collecting plate to not contact the positive electrode assembly, when the battery is in use, the positive and negative electrodes will not overlap due to the central tube itself being made of metal, causing internal short circuit problems, which is beneficial to improving the cycle performance and safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the overall structure diagram of this program;

[0023] Figure 2 An overall overview of this plan Figure 1 ;

[0024] Figure 3 An overall overview of this plan Figure 2 .

[0025] The meaning of each number in the figure is:

[0026] 100. Battery body; 101. Casing; 110. Negative electrode assembly; 111. Negative electrode cap; 112. Negative electrode current collector; 113. Center tube; 120. Positive electrode assembly; 121. Positive electrode terminal; 122. Insulating gasket; 123. First sealant; 124. Second sealant; 125. Positive electrode current collector. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Example

[0029] Currently, most batteries have a central tube 113 inside the battery casing to cope with the expansion and contraction of the electrode sheets. The wound electrode assembly is wound around the central tube 113, and the two ends of the central tube 113 are connected to the positive and negative electrode connecting tabs, respectively. When the electrode sheets expand, the resistance of the central tube 113 itself will restrain the electrode sheets. However, due to the corrosive nature of the electrolyte, the central tube 113 is mostly made of corrosion-resistant metal materials. When the two ends of the central tube 113 made of metal materials are connected to the positive and negative electrode connecting tabs, respectively, the positive and negative electrodes will overlap, causing internal short circuits.

[0030] Therefore, see Figure 1 and Figure 2 As shown, the purpose of this embodiment is to provide a battery that prevents internal short circuit, including a battery body 100, the battery body 100 includes a shell 101, and 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 cover end 111, a negative electrode current collecting plate 112 and a central tube 113. Considering that the central tube 113 cannot be connected to the positive electrode connecting plate and the negative electrode connecting plate, thereby forming a positive and negative electrode overlap, causing the internal short circuit phenomenon, the negative electrode cover end 111, the negative electrode current collecting plate 112 and the central tube 113 are fixed in sequence from bottom to top; the central tube 113 is installed in the shell 101, and the end of the central tube 113 away from the negative electrode current collecting plate 112 is separated from the positive electrode assembly 120.

[0031] The improvement of this embodiment lies in that: by arranging a central tube 113 on the negative electrode current collecting disk 112, the addition of the central tube 113 avoids the collapse of the electrode sheet and, at the same time, provides good support for the expansion and contraction of the negative electrode; by arranging the end of the central tube 113 away from the negative electrode current collecting disk 112 to not contact the positive electrode assembly 120, when the battery is in use, the central tube 113 itself is made of metal, which will not cause the positive and negative electrodes to overlap and cause internal short circuit problems, thereby improving the cycle performance and safety of the battery.

[0032] See also Figure 3 As shown, in order to facilitate the installation of the positive terminal 121, one end of the housing 101 is a closed end, and a through groove is provided at the center of the closed end of the housing 101. The positive electrode assembly 120 includes the positive terminal 121, and the positive terminal 121 is installed at the closed end of the housing 101 through the through groove, thereby installing the positive terminal 121 on the housing 101;

[0033] The positive electrode assembly 120 further includes a positive electrode current collecting plate 125 mounted within the inner cavity of the housing 101. To prevent the positive electrode current collecting plate 125 from contacting the housing 101 and causing the surface of the housing 101 to become charged, one end of the positive electrode terminal 121 is welded to one side of the positive electrode current collecting plate 125.

[0034] At the same time, to prevent the positive terminal 121 from contacting the outer shell 101 and causing the surface of the outer shell 101 to be charged, 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. The sealant and the insulating gasket 122 are used to prevent the positive terminal 121 and the outer shell 101 from contacting each other, thereby eliminating the possibility of the surface of the outer shell 101 being charged.

[0035] The housing 101 has an open end opposite to the closed end. Considering the sealing performance of the battery body 100, the open end of the housing 101 is sealed and fixed to the negative electrode cover 111 by laser welding. The housing 101 is sealed with sealant, an insulating gasket 122 and a positive electrode terminal 121.

[0036] A wound electrode group is further provided between the negative electrode assembly 110 and the positive electrode assembly 120. The ends of the wound electrode group are welded to the positive electrode current collecting disc 125 and the negative electrode current collecting disc 112, respectively. The welding strengthens the connection between the wound electrode group, the positive electrode current collecting disc 125, and the negative electrode current collecting disc 112, thereby enhancing the stability of the internal structure of the battery and preventing loosening or damage to the internal components due to expansion and contraction during the charge and discharge process.

[0037] Since the winding electrode group itself is wound around the winding needle, the winding needle is pulled out after the winding of the winding electrode group is completed. Therefore, the outer diameter of the winding needle and the center tube 113 are the same, which is equivalent to the winding electrode group being arranged in a circle with the center tube 113 as the center.

[0038] Considering the expansion and contraction of the negative electrode sheet during charge and discharge, one side of the negative electrode sheet needs to be completely in contact with the central tube 113 to suppress the expansion of the negative electrode sheet. Therefore, the length of the central tube 113 is equal to the length of the negative electrode sheet plus 1 mm to support the expansion of the negative electrode. At the same time, the central tube 113 does not contact the positive electrode current collecting plate 125 to cause a short circuit.

[0039] Taking into account that the battery design needs to be targeted according to different usage scenarios, the shape of the central tube 113 is spiral, mesh or barrel. When the central tube 113 is spiral, the surface area of ​​the central tube 113 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 the charge and discharge process in time, preventing the battery from overheating and damage; when the central tube 113 is barrel-shaped, it can provide stable support for the inside of the battery, which helps to maintain the flatness and position accuracy of the electrode sheets and diaphragms.

[0040] Due to the expansion and contraction of the negative electrode sheet during charging and discharging, the central tube 113 and the outer shell material 101 must have excellent elastic recovery, deformation resistance, durability, and corrosion resistance. Therefore, both the central tube 113 and the outer shell 101 are made of a shape memory alloy. This material has a unique shape memory effect, that is, after being deformed by external forces, it can return to its original shape under certain conditions. This property enables the shape memory alloy material to adapt well to the expansion and contraction of the negative electrode sheet, maintaining the stability and integrity of the internal structure of the battery. At the same time, the shape memory alloy material has excellent elasticity and recovery ability, and can withstand large deformation without cracking or permanent deformation. Shape memory alloy materials generally have good electrical conductivity, thermal conductivity, mechanical strength, and durability. In this embodiment, the shape memory alloy material includes but is not limited to TiNi-based shape memory alloys, copper-based shape memory alloys, and iron-based shape memory alloys.

[0041] In summary, the working principle of this solution is as follows:

[0042] When the battery is charging, the negative electrode sheet of the battery will expand. At this time, the central tube 113 and the outer shell 101 will be deformed. The central tube 113 and the outer shell 101 themselves are made of memory alloy materials. Their metallic properties will inhibit the expansion of the negative electrode sheet, thereby supporting the expansion of the negative electrode sheet, restraining the electrode sheet, and preventing the gap between the battery cells from becoming larger. Similarly, when the battery is discharging, the negative electrode sheet shrinks, and the central tube 113 and the outer shell 101 are also used to restrain the electrode sheet; at the same time, the central tube 113 is only fixed to the negative electrode current collecting plate 112, so that no matter whether the battery is charging or discharging, the positive and negative electrodes will not be overlapped due to the central tube 113, resulting in internal short circuit. In addition, since the central tube 113 is made of metal, it can also play a good heat conductive role, improving the safety and cycle performance of the battery cell.

[0043] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0044] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. A battery for preventing internal short circuit, comprising a battery body (100), wherein the battery body (100) comprises a shell (101), and a negative electrode assembly (110) and a positive electrode assembly (120) are respectively provided at two ends of the shell (101), characterized in that: The negative electrode assembly (110) comprises a negative electrode cover end (111), a negative electrode current collecting disc (112) and a central tube (113), wherein the negative electrode cover end (111), the negative electrode current collecting disc (112) and the central tube (113) are fixed in sequence from bottom to top; the central tube (113) is installed in the housing (101), and one end of the central tube (113) away from the negative electrode current collecting disc (112) is separated from the positive electrode assembly (120).

2. The internal short circuit-proof battery according to claim 1, characterized in that: One end of the shell (101) is a closed end, and the other end of the shell (101) is an open end; a through slot is provided at the center of the closed end of the shell (101); the positive electrode assembly (120) includes a positive terminal (121); and the positive terminal (121) is mounted on the closed end of the shell (101) through the through slot.

3. The internal short circuit-proof battery according to claim 2, characterized in that: The positive electrode assembly (120) further comprises a positive electrode current collecting disc (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 collecting disc (125).

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

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

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

7. The internal short circuit-proof battery 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 internal short circuit-proof battery 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 internal short circuit-proof battery according to claim 1, characterized in that: The central tube (113) is in the shape of a spiral, a mesh or a cylinder.

10. The internal short circuit-proof battery according to claim 1, characterized in that: The central tube (113) and the outer shell (101) are both made of memory alloy.

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