Lithium ion battery case, lithium ion battery, power device

Abstract

The utility model provides a lithium ion battery shell, lithium ion battery, power equipment belongs to lithium ion battery thermal runaway control technical field. Including electric core chamber, buffer chamber, piston unit, the baffle between electric core chamber and buffer chamber has the liquid inlet and the liquid outlet, and installs the liquid inlet check valve and the liquid outlet check valve respectively in the liquid inlet and the liquid outlet, piston unit adjusts the cavity size of buffer chamber. The utility model discloses a design liquid inlet check valve and liquid outlet check valve on the baffle, cooperate piston unit, can realize the electrolyte in electric core chamber and draw to buffer chamber, or inject the electrolyte in buffer chamber into electric core chamber, can draw the electrolyte in the inside of electric core chamber when BMS detects the battery thermal runaway, restrains the further development of thermal runaway, also can unify the liquid injection of liquid injection by the car machine, thereby promotes the security and the service life of battery.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery thermal runaway suppression technology, specifically a lithium-ion battery casing, a lithium-ion battery, and a power device. Background Technology

[0002] Currently, the safety and lifespan of new energy lithium-ion batteries are receiving widespread attention. In lithium-ion battery systems, the electrolyte is the most critical material affecting safety and lifespan. During thermal runaway, the main source of heat is the decomposition of the electrolyte. Throughout the battery's lifespan, side reactions and consumption of the electrolyte are also key factors influencing battery life.

[0003] When signs of thermal runaway are detected, the electrolyte cannot be isolated from the positive and negative electrodes in a timely manner to curb its further development. During storage, the contact area between the electrolyte and the positive and negative electrodes cannot be adjusted, allowing side reactions to continue, uncontrolled electrolyte consumption, and impacting battery lifespan.

[0004] Furthermore, when lithium-ion batteries are left unused, they are prone to self-discharge, passivation of positive and negative electrode materials, and electrolyte decomposition due to the inherent properties of the battery. Instability in the SEI (Sediment Injection) performance of the negative electrode leads to rapid degradation of the active material and facilitates lithium metal deposition. Moreover, different electrolyte components have varying degrees of impact on electrode material degradation. Therefore, current technologies lack proper electrolyte handling measures for unused lithium-ion batteries. Utility Model Content

[0005] The technical problem to be solved by this utility model is to design a structure that can extract or inject electrolyte from the cell cavity.

[0006] This utility model solves the above-mentioned technical problems through the following technical means:

[0007] A lithium-ion battery casing includes a cell cavity, a buffer cavity, and a piston unit; an inlet and an outlet are provided on a partition between the cell cavity and the buffer cavity, and an inlet check valve and an outlet check valve are respectively installed at the inlet and outlet; the piston unit adjusts the size of the buffer cavity.

[0008] This invention, by designing an inlet and outlet check valve on the separator and working with a piston unit, can extract the electrolyte from the cell cavity to the buffer cavity, or inject the electrolyte from the buffer cavity into the cell cavity. When the BMS detects battery thermal runaway, the electrolyte inside the cell cavity can be extracted to suppress the further development of thermal runaway. Alternatively, the electrolyte can be uniformly extracted and injected by the vehicle's system, thereby improving battery safety and lifespan.

[0009] Furthermore, the piston unit includes a movable plate and a drive mechanism; the movable plate is in a sealed and movable fit with the surrounding side walls of the buffer cavity, and the drive mechanism drives the movable plate to move.

[0010] Furthermore, the drive mechanism is an electric cylinder.

[0011] Furthermore, the electric cylinder is communicatively connected to the BMS.

[0012] Furthermore, the battery housing includes a closed outer shell, and the separator and movable plate divide the inner cavity of the outer shell into a cell cavity, a buffer cavity, and a mounting cavity for fixing the drive mechanism.

[0013] Furthermore, the partition and the movable plate are arranged in parallel.

[0014] Furthermore, the output end of the electric cylinder has a radial umbrella-shaped structure and is fixed to the center of the bottom of the movable plate.

[0015] Furthermore, the movable plate is sealed to the inner wall of the buffer cavity by multiple sealing rings.

[0016] This utility model also provides a lithium-ion battery, including the aforementioned casing.

[0017] This utility model also provides a power device, including the aforementioned lithium-ion battery.

[0018] The advantages of this utility model are: This invention, by designing inlet and outlet check valves on the separator, in conjunction with a piston unit, can extract electrolyte from the cell cavity to the buffer cavity, or inject electrolyte from the buffer cavity into the cell cavity. This allows for the extraction of electrolyte from the cell cavity when the BMS detects battery thermal runaway, suppressing further thermal runaway. Alternatively, the electrolyte can be extracted and injected uniformly by the vehicle's infotainment system, thereby improving battery safety and lifespan. Electrolyte can also be extracted when the battery has been idle for an extended period to prolong battery life.

[0019] The output end of the electric cylinder adopts a radial umbrella-shaped structure, which can transmit force evenly and prevent the moving plate from tilting and jamming. Attached Figure Description

[0020] Figure 1 This is a perspective view of the lithium-ion battery casing and a partial internal structure schematic diagram in Embodiment 1 of this utility model; Figure 2 This is a vertical cross-sectional view and a partially enlarged schematic diagram of the lithium-ion battery casing in Embodiment 1 of this utility model.

[0021] Among them, the outer shell-1, the partition-2, the movable plate-3, the drive mechanism-4, the liquid inlet check valve-21, and the liquid outlet check valve-22 are all included. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] Example 1 This embodiment describes a lithium-ion battery casing, such as... Figure 1 , Figure 2 As shown, the casing 1 includes a three-dimensional and a cylindrical shape, respectively, for square and cylindrical batteries. This embodiment uses a square battery as an example. A separator 2 and a movable plate 3 are fixed inside the casing 1. The separator 2 and the movable plate 3 are arranged in parallel. The separator 2 is located above the movable plate 3, and the separator 2 is sealed and fixed to the inner wall of the casing 1, such as by welding or integral stamping. The sealed cavity above the separator 2 is the cell cavity. The cavity between the separator 2 and the movable plate 3 is the buffer cavity, and the cavity between the movable plate 3 and the bottom plate of the casing 1 is the mounting cavity. The drive mechanism 4 is fixed in the mounting cavity, and the drive mechanism 4 and the movable plate 3 constitute a piston unit. In this embodiment, an inlet and an outlet are opened on the separator 2, and an inlet check valve 21 and an outlet check valve 22 are installed at the inlet and outlet, respectively. The piston unit adjusts the size of the buffer cavity, thereby allowing the electrolyte in the cell cavity to be drawn into the buffer cavity or the electrolyte in the buffer cavity to be injected into the cell cavity.

[0024] In this embodiment, the movable plate 3 is in a sealed, movable fit with the surrounding side walls of the buffer cavity, which can be based on the sealing fit structure between the piston and the outer cylinder wall of a syringe, such as... Figure 2 As shown, the sealing performance can be improved by using multiple rubber rings 31. Specifically, multiple limiting grooves can be opened around the movable plate 3, and the rubber rings 31 are fitted into the limiting grooves. For better sealing, the rubber rings protrude from the limiting grooves by a certain size, which is generally 0.5-1mm.

[0025] The driving mechanism 4 in this embodiment can be, but is not limited to, an electric cylinder. Its output end is fixed to the bottom of the movable plate 3, and its base is fixed to the bottom plate of the mounting cavity, i.e., the bottom plate of the outer casing 1. To ensure the stability of the movable plate 3 during movement, the output end of the electric cylinder can be widened to increase the contact area with the bottom of the movable plate 3, so that the movable plate 3 is subjected to uniform force and to prevent the movable plate 3 from tilting and jamming with the outer casing 1 due to uneven force. Specifically, the output end of the electric cylinder can be designed as a radial umbrella-shaped structure, similar to the umbrella-shaped structure at the end of a syringe piston rod. The umbrella-shaped structure is fixed to the bottom of the movable plate 3 and can transmit force evenly. When the electric cylinder is controlled by the BMS (Battery Management System), when the BMS determines that the battery has experienced thermal runaway, it will control the electric cylinder to start, driving the movable plate 3 to move downward, thereby drawing the electrolyte in the cell cavity from the liquid outlet check valve 22 into the buffer cavity, thus suppressing the further development of thermal runaway. In this embodiment, the BMS is existing technology, and only one control logic for the electric cylinder needs to be added. This control logic can adopt existing technology and is not the focus of innovation in this embodiment. The key feature of this embodiment is to provide a housing that can separate the electrolyte from the cell cavity and suppress the spread of thermal runaway.

[0026] When a car is parked and not in use for an extended period, to prevent damage to the battery, the electric cylinder can be manually activated to drain the electrolyte. This requires an additional manual control button. This button controls the starting and stopping of the electric cylinder and can be mounted on the main control panel in the driver's cabin or other easily accessible location. The specific circuitry is existing technology and will not be detailed further.

[0027] Example 2 This embodiment provides a lithium-ion battery that uses the casing from Embodiment 1.

[0028] Example 3 This embodiment provides a power device that uses the lithium-ion battery of Embodiment 2.

[0029] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A lithium-ion battery casing, characterized in that, It includes a cell cavity, a buffer cavity, and a piston unit; the partition between the cell cavity and the buffer cavity has an inlet and an outlet, and an inlet check valve and an outlet check valve are installed at the inlet and outlet respectively; the piston unit adjusts the size of the buffer cavity.

2. The lithium-ion battery casing according to claim 1, characterized in that, The piston unit includes a movable plate and a drive mechanism; the movable plate is in a sealed and movable fit with the four sides of the buffer cavity, and the drive mechanism drives the movable plate to move.

3. The lithium-ion battery casing according to claim 2, characterized in that, The drive mechanism is an electric cylinder.

4. The lithium-ion battery casing according to claim 3, characterized in that, The electric cylinder is connected to the BMS for communication.

5. The lithium-ion battery casing according to claim 2 or 3, characterized in that, The battery housing includes a closed outer shell, and the separator and movable plate divide the inner cavity of the outer shell into a cell cavity, a buffer cavity, and a mounting cavity for fixing the drive mechanism.

6. The lithium-ion battery casing according to claim 2 or 3, characterized in that, The partition and the movable plate are arranged in parallel.

7. The lithium-ion battery casing according to claim 3, characterized in that, The output end of the electric cylinder has a radial umbrella-shaped structure and is fixed to the center of the bottom of the movable plate.

8. The lithium-ion battery casing according to claim 2 or 3, characterized in that, The movable plate is sealed to the inner wall of the buffer cavity by multiple sealing rings.

9. A lithium-ion battery, characterized in that, Includes the housing as described in any one of claims 1 to 8.

10. A power equipment, characterized in that, Including the lithium-ion battery as described in claim 9.

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