A safety structure of a large capacity lithium ion battery and a battery using the same

Abstract

The application relates to a safety structure of a large-capacity lithium ion battery and a large-capacity lithium ion battery using the safety structure, wherein the safety structure is that a phase-changeable fire-fighting cooling medium is added in a center column of the lithium ion battery, the center column is in contact with or protrudes from an upper or lower cover body of the battery. In normal operation of the battery, the fire-fighting cooling medium can produce phase change, transfer the heat in the battery to the outside, exchange heat, and reduce the temperature of the battery core. When the battery will be in thermal runaway due to internal short circuit or other reasons, the center column releases the fire-fighting cooling medium to the inside of the battery in the heating process, cools the battery, and blocks or delays the thermal runaway of the battery. Even if the battery is in thermal runaway finally, the fire-fighting cooling medium is mixed with the gas generated by the thermal runaway of the battery and is sprayed out from a pressure relief port, non-combustible gas generated by the thermal runaway of the battery is non-combustible, and the safety of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more particularly to a safety structure for a high-capacity lithium-ion battery and a high-capacity lithium-ion battery using the safety structure. Background Technology

[0002] Thermal runaway of lithium batteries is the main cause of safety accidents involving lithium batteries. When lithium plating inside the battery punctures the separator, the battery short-circuits, the battery is punctured, or the temperature exceeds the limit, thermal runaway can easily occur. After thermal runaway, the battery can cause fires in adjacent batteries, or even the entire battery box and the entire battery room. If the smoke generated by the thermal runaway diffuses into the space and reaches the explosive concentration, it can also easily cause an explosion, resulting in incalculable personal and property losses.

[0003] Due to the presence of ohmic heat, polarization heat, and side reaction heat during charging and discharging, heat accumulates inside lithium batteries during charge-discharge cycles, causing the temperature to rise higher and higher. If not cooled in time, the safety of the battery will be severely tested. Currently, most battery cooling methods use coolant or air conditioning for surface cooling, which has poor cooling efficiency and mediocre effect.

[0004] CN 102437370A discloses a cooler for a battery with a central column (core) as the container. The cooler can release flame-retardant gas under temperature or pressure. When the battery experiences thermal runaway, it cools the battery. In addition to fire protection and cooling the battery during thermal runaway, the central column also plays a role in heat conduction during normal battery operation. It conducts heat generated inside the battery during charging and discharging, cools the battery, reduces heat accumulation, and improves battery safety.

[0005] CN206098596 U describes the structure of the central column as the fire extinguishing core, but does not specify what the fire extinguishing agent medium used inside is, nor does it mention the method of using the central column as a heat pipe to conduct the heat of the battery during normal operation outside the battery body. Compared with the technical effect of this patent, there is a big gap. Summary of the Invention

[0006] To address the shortcomings of the existing equipment, this application proposes a safety structure for a high-capacity lithium-ion battery and a high-capacity lithium-ion battery including the safety structure.

[0007] A safety structure for a high-capacity lithium-ion battery, the safety structure including a battery center post disposed in the battery, the battery center post contacting or protruding from the upper / lower battery cover;

[0008] The battery's central column contains a phase-changeable cooling medium. During normal battery operation, the cooling medium can transfer heat from inside the battery to the outside through phase change, thus exchanging heat and reducing the temperature of the battery core. Before the battery is about to experience thermal runaway due to an internal short circuit or other reasons, the central column releases the cooling medium into the battery during the heating process to cool the battery, thereby blocking or delaying thermal runaway.

[0009] Preferably, the battery center column is a hollow metal column.

[0010] Preferably, the surface of the hollow metal cylinder has liquid outlet holes, which are sealed by a fusible alloy, and melt to release fire extinguishing and cooling substances when the battery temperature rises.

[0011] Preferably, the melting point of the fusible alloy is greater than or equal to 130°C.

[0012] Preferably, the surface of the hollow metal column has a weak groove, which can crack and release the fire extinguishing and cooling medium when the internal pressure of the column increases.

[0013] Preferably, when the internal pressure of the battery or the internal pressure of the central column is between 0.2 and 0.4 MPa, the weak groove opens to release the fire extinguishing and cooling medium.

[0014] Preferably, the fire-fighting cooling medium contained inside the central column of the battery is a fire-fighting material with strong fire-fighting ability and phase-change cooling capability.

[0015] Preferably, the fire extinguishing material is perfluorohexanone or its homologues.

[0016] Preferably, the top surface of the battery center column is in close contact with or protrudes from the central axis of the upper or lower battery cover.

[0017] Preferably, the pressure relief port of the battery is located at the top of the central column or at other locations on the upper and lower covers, and a gas collection device is connected to the pressure relief port.

[0018] Preferably, the interior of the battery center column is evacuated to a vacuum level of 3×10⁻⁶. -1 ~10 -4 Pa.

[0019] Another aspect of this application provides a high-capacity lithium-ion battery, which includes the safety structure of any of the preceding high-capacity lithium-ion batteries.

[0020] Preferably, it also includes a semiconductor cooling unit and / or heat sink fins disposed at the top or side of the central column.

[0021] The safety structure of the high-capacity lithium-ion battery in this application involves adding a fire-fighting cooling medium or a catalytic reaction medium inside the central column of the lithium-ion battery. When the battery is about to experience thermal runaway due to an internal short circuit or other reasons, the central column releases the fire-fighting cooling medium into the battery during the heating process to cool the battery or cause the electrolyte solution to react, thereby blocking or delaying the thermal runaway of the battery and improving the battery's safety. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0023] Figure 1 It is a metal central column containing fire-fighting cooling medium with a weak groove.

[0024] Figure 2 This is a schematic diagram of a metal central column containing fire-fighting cooling medium, with a fusible metal seal at the bottom.

[0025] Figure 3 A schematic diagram of a top cover with a non-protruding central pillar.

[0026] Figure 4 A schematic diagram of the top cover with a protruding central pillar.

[0027] Figure 5 This is a schematic diagram of a battery with a central column containing a phase-change fire-fighting medium that does not extend beyond the top cover.

[0028] Figure 6 This is a schematic diagram of a battery with a central column containing a phase-change fire-fighting medium extending from the top cover.

[0029] Figure 7 This is a schematic diagram of a semiconductor cooling center column.

[0030] Figure 8 This is a schematic diagram of the cooling center column for the heat sink fins.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Weak groove, 2-Center post, 3-Battery cover, 4-Center post protruding cover, 5-Battery with center post not protruding from cover, 6-Battery with center post protruding from cover, 7-Semiconductor cooling chip, 8-Heat dissipation fins, 9-Pressure relief port, 10-Center post welding piece. Detailed Implementation

[0033] The technical solutions in 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.

[0034] like Figures 1 to 7 As shown:

[0035] like Figure 1 The cooling fire extinguishing medium is sealed in a central column with multiple weak grooves 1. The central column is placed into the core, and the positive and negative electrodes are welded on. Figure 1 The central column is welded to the battery cover 3, liquid is injected, sealed, and formed to form a battery 5 in which the central column does not protrude from the cover.

[0036] like Figure 2 The cooling fire extinguishing medium is sealed in a central column with a fusible metal weak point at the bottom. The top of the central column has a battery pressure relief port 9. Positive and negative electrode tabs are welded on. The central column is then placed into the core. Figure 2 The central pillar welding piece 10 is welded to the central pillar protruding top cover 4, liquid is injected, the opening is sealed, and formation is performed to form the battery 6 with the central pillar protruding top cover.

[0037] like Figure 7 , 8 As shown, both the battery 5 with a central column not protruding from the top cover and the battery 6 with a central column protruding from the top cover can have a semiconductor cooling chip 7 or heat dissipation fins 8 added to the top or side of the central column to cool the hot end of the central column during battery operation. Alternatively, air cooling and water cooling can be used to cool the top of the central column.

[0038] Before thermal runaway occurs, the weak groove in the center post opens, releasing perfluorohexanone into the battery, preventing or delaying thermal runaway. The positive and negative terminals can be located at the same end as the contact surface or protruding surface of the center post and the top and bottom covers of the battery, or at opposite ends.

[0039] As is known from common technical knowledge, this application can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this application or equivalent to this application are included in this application.

Claims

1. A safety structure for a high-capacity lithium-ion battery, characterized in that, It includes a battery center column disposed in the battery, the battery center column protruding from the battery cover, and a pressure relief port provided at the top of the battery center column, and a gas collection device connected to the pressure relief port; The battery center column is a hollow metal column; the surface of the hollow metal column is provided with liquid outlet holes, which are sealed by a fusible alloy; The battery's central column contains a fire-fighting cooling medium that can undergo phase change. The fire-fighting and cooling medium contained inside the battery's central column is a fire-fighting material with strong fire-fighting capabilities and capable of phase-change cooling; the fire-fighting material is perfluorohexanone or its homologues; It also includes a semiconductor cooling unit and / or heat dissipation fins disposed on the top or side of the central column to cool the hot end of the central column during battery operation; During normal battery operation, the fire-fighting cooling medium can undergo a phase change to transfer heat from inside the battery to the outside, thereby exchanging heat and reducing the temperature of the battery core. Before the battery is about to experience thermal runaway due to an internal short circuit or other reasons, the central column of the battery releases a fire-fighting cooling medium into the battery during the heating process to cool the battery and block or delay the thermal runaway.

2. The safety structure of the high-capacity lithium-ion battery according to claim 1, characterized in that, The melting point of the fusible alloy is greater than or equal to 130°C.

3. The safety structure of the high-capacity lithium-ion battery according to claim 1, characterized in that, The battery's central column is subjected to a vacuum treatment, with a vacuum level of 3×10⁻⁶. -1 ~10 -4 Pa.

4. A high-capacity lithium-ion battery, characterized in that, It includes the safety structure of a high-capacity lithium-ion battery as described in any one of claims 1 to 3, and a semiconductor cooling unit and / or heat dissipation fins disposed on the top or side of the central pillar.

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