A thermal battery
By introducing a central heating component and an inner tube design into the thermal battery, the problems of long activation time in low-temperature environments and thermal runaway in high-temperature environments are solved, enabling reliable operation over a wide temperature range, suitable for polar, high-altitude, and cryogenic regions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WEIFANG UNIV OF SCI & TECH
- Filing Date
- 2026-04-30
- Publication Date
- 2026-07-14
AI Technical Summary
Existing thermal batteries have prolonged activation time and drop in output voltage at low temperatures, and pose a risk of thermal runaway at high temperatures, making it difficult to achieve dynamic balance in thermal management over a wide operating temperature range.
The battery stack is preheated by a central heating component, and the temperature of the battery stack is controlled by an inner tube. The inner tube is designed as an insulated tube and is tightly fitted to the individual thermal cells. The inner tube is equipped with a heating component or electric heating element, and the outer side is equipped with an explosion-proof diaphragm and an outer expansion ring to realize the current collection function.
It can quickly activate the battery stack in low-temperature environments, avoiding start-up delays and insufficient output, and prevent thermal runaway in high-temperature environments, thus improving the reliability and safety of the battery. It is suitable for polar, high-altitude and cryogenic regions.
Smart Images
Figure CN122393328A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of primary battery technology, specifically to a thermal battery. Background Technology
[0002] A thermal battery is a disposable storage battery that uses molten salt as the electrolyte. It has advantages such as short activation time, high output power, wide operating temperature range, long storage time, and strong impact resistance. The working principle of a thermal battery is as follows: In the storage state, the solid electrolyte inside does not have ionic conductivity, and the thermal battery is in a dormant state with no energy output. When it receives an external activation command, the ignition mechanism inside the thermal battery ignites the heating agent. The heat released by the heating agent melts the solid electrolyte into a liquid state, thereby establishing an ionic conductivity channel. The thermal battery is then activated and outputs electrical energy. Thermal batteries are used in aerospace, deep-sea exploration, and various emergency rescue systems.
[0003] The heat output of the heating agent inside existing thermal batteries is fixed at the factory. This causes the internal temperature and operating temperature curves of the thermal battery after activation to change with the ambient temperature. On the one hand, in environments close to the lower limit of the operating temperature, some of the heat released after the heating agent burns is used to compensate for the ambient temperature difference, resulting in slow heating inside the battery stack. The solid electrolyte cannot melt quickly and fully, or even if it melts, it is difficult to reach the optimal operating temperature. This leads to prolonged activation time, a risk of voltage drop in output, and a significant reduction in battery life, failing to meet the power requirements of equipment at low temperatures. On the other hand, when the ambient temperature is close to the upper limit of the thermal battery's operating temperature, the high ambient base temperature combined with the instantaneous heat released by the heating agent causes heat accumulation inside the battery stack. The peak temperature inside the battery is very likely to exceed the safety threshold. At this time, the active materials on the positive and negative electrodes will undergo thermal decomposition, causing the electrode skeleton to melt and deform, triggering thermal runaway of the thermal battery. This can lead to premature battery failure or, in severe cases, battery casing bulging, cracking, or even explosion.
[0004] Existing thermal battery structures use a fixed internal heat source configuration, making it difficult to achieve a dynamic balance in thermal management over a wide operating temperature range where the heat penetrates at low temperatures and the heat penetrates at high temperatures. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide a thermal battery that uses central heating in an environment close to the lower limit of the operating temperature, thereby reducing the total amount of heating agent used and making it easy to control the maximum operating temperature inside the battery stack. This allows the thermal battery to work reliably for a long time when the ambient temperature is close to the upper and lower limits of the thermal battery's operating temperature.
[0006] The technical solution adopted by this invention to solve its technical problem includes: On one hand, a thermal battery is provided, including a shell, an end cap, a first heat insulation layer, an insulating and heat-insulating bushing, a battery stack, and a second heat insulation layer. One end of the shell is provided with an opening, and the inner wall of the shell is provided with an insulating and heat-insulating bushing. The first heat insulation layer, the battery stack, and the second heat insulation layer are arranged sequentially from the inside to the outside in the inner cavity of the shell. The opening of the shell is fixedly connected to the end cap, and the battery stack is formed by stacking several individual thermal batteries sequentially along the axial direction.
[0007] The battery stack has an axial center position with a mounting through hole. An inner tube is coaxially inserted through the mounting through hole. The outer side of the inner tube is tightly fitted with the inner wall of the hole of each individual thermal battery. The inner tube is a hollow insulating tube sealed at both ends. A heating component is provided in the inner cavity of the inner tube.
[0008] As a preferred embodiment of the present invention, the heating component is a long tube located inside the inner tube, and the outer side of the long tube is provided with a plurality of protrusions that abut against the inner wall of the inner tube.
[0009] The long tube is filled with an exothermic agent and is equipped with an electric igniter. The wire of the electric igniter runs through the long tube, the second heat insulation layer, the end cap, and extends to the outside of the shell.
[0010] As a preferred embodiment of the present invention, the heating component is an electric heating element that is attached to the inner wall of the inner tube, and the wire of the electric heating element passes through the long tube, the second heat insulation layer, the end cap and extends to the outside of the shell.
[0011] As a preferred embodiment of the present invention, the length of the inner tube is greater than the axial thickness of the battery stack, and at least one axial end of the inner tube is sealed by installing an explosion-proof diaphragm. The end of the inner tube with the explosion-proof diaphragm extends to the outside of the mounting through hole of the battery stack.
[0012] The pressure difference between the shell and the inner tube is greater than 50.0 kPa.
[0013] As a preferred embodiment of the present invention, a thin tube is provided inside the second heat insulation layer, one end of the thin tube is close to the insulating heat insulation bushing, and the other end of the thin tube is close to the explosion-proof diaphragm.
[0014] As a preferred embodiment of the present invention, the inner tube includes a metal tube, and an insulating layer is provided on the outside of the metal tube. The insulating layer is an alumina ceramic layer, an enamel coating, a boron nitride coating, a silicon nitride coating, a phosphate coating, or a mica sheet coating.
[0015] As a preferred embodiment of the present invention, one end of the inner tube extends radially outward with an outer expansion ring, the outer expansion ring being located between the battery stack and the first heat insulation layer, and an end plate being provided between the battery stack and the second heat insulation layer.
[0016] On the other hand, another type of thermal battery is also provided, including a housing, an end cap, a first heat insulation layer, an insulating and heat-insulating bushing, a battery stack, a second heat insulation layer, a first terminal and a second terminal. One end of the housing is provided with an opening, and the inner wall of the housing is provided with an insulating and heat-insulating bushing. The first heat insulation layer, the battery stack and the second heat insulation layer are arranged sequentially from the inside to the outside in the inner cavity of the housing. The opening of the housing is fixedly connected to the end cap, and the battery stack is composed of several individual thermal batteries stacked sequentially along the axial direction.
[0017] The battery stack has a mounting through hole at its axial center position. An inner tube is coaxially inserted through the mounting through hole. The outer side of the inner tube is tightly fitted with the inner wall of the inner hole of each individual thermal battery. Both ends of the inner tube are sealed.
[0018] The inner tube includes a metal tube with an insulating layer on the outside. One end of the metal tube has a radially outwardly extending metal ring, which is located between the battery stack and the heat insulation layer.
[0019] The outer expansion ring is electrically connected to one electrode of the battery stack, the other electrode of the battery stack is electrically connected to the end of terminal one, the metal tube away from the outer expansion ring is electrically connected to the end of terminal two, and both terminal one and terminal two pass through the heat insulation layer two and the end cap and extend to the outside of the housing.
[0020] As a preferred embodiment of the present invention, the length of the inner tube is greater than the axial thickness of the battery stack, and at least one axial end of the inner tube is sealed by installing an explosion-proof diaphragm.
[0021] The pressure difference between the air inside the shell and the air pressure inside the inner tube is greater than 50 kPa.
[0022] On the other hand, another type of thermal battery is also provided, including a shell, an end cap, a heat insulation layer one, an insulating and heat-insulating bushing, a battery stack, and a heat insulation layer two. One end of the shell is provided with an opening, and the inner wall of the shell is provided with an insulating and heat-insulating bushing. The heat insulation layer one, the battery stack, and the heat insulation layer two are arranged sequentially from the inside to the outside in the inner cavity of the shell. The opening of the shell is fixedly connected to the end cap, and the battery stack is composed of several individual thermal batteries stacked sequentially along the axial direction.
[0023] An installation hole is provided in the middle of the end cap, and an installation through hole is provided at the axial center of the battery stack. An insulating inner tube is coaxially inserted in the installation through hole. The outer side of the inner tube is tightly fitted with the inner wall of the inner hole of each individual thermal battery. One end of the inner tube near the bottom of the inner cavity of the shell is closed. A fixing tube is fixedly installed at the other end of the inner tube. The fixing tube passes through the heat insulation layer and the end cap and is fixedly connected to the installation hole. A sealing component is installed inside the fixing tube.
[0024] The fixed tube is a mica tube, ceramic tube, or glass tube, and a heating component is provided in the inner cavity of the inner tube.
[0025] Compared with the prior art, the beneficial effects of the present invention are: 1. The thermal battery of the present invention, in an environment close to the lower limit of the operating temperature, the heating component first preheats the battery stack through the inner tube, and then the battery stack is activated. The temperature of the activated battery stack quickly reaches the optimal operating temperature, avoiding problems such as start-up delay, insufficient output power and inability to activate, and fully meeting the usage requirements of polar, high-altitude and cryogenic regions.
[0026] 2. In the thermal battery of the present invention, at least one axial end of the inner tube is sealed by installing an explosion-proof diaphragm. The pressure difference between the gas inside the shell and the gas inside the inner tube is greater than 50.0 kPa. When the battery stack reacts abnormally and the gas pressure inside the shell exceeds the limit pressure, the explosion-proof diaphragm will rupture. The gas generated by the battery stack will enter the long tube through the ruptured explosion-proof diaphragm, avoiding damage to the shell. The pressure relief is without open flame or liquid slag splash.
[0027] 3. In the example thermal battery of the present invention, the inner tube and the outer expansion ring serve as current collectors, which shortens the internal electron transmission path, reduces the internal resistance of the thermal battery, improves the thermal battery's ability to cope with pulsed high current discharge, and saves space for setting up a separate current collector.
[0028] 4. In the example of the thermal battery of the present invention, the inner tube provides radial constraint for each individual thermal battery to avoid misalignment of the individual thermal batteries caused by vibration and impact. The end plate and the outer expansion ring facilitate the application of axial preload to the battery stack to compensate for the thermal expansion and sintering shrinkage of the battery stack at high temperature and avoid gaps between adjacent individual thermal batteries. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a partial cross-sectional view of an embodiment of the present invention; Figure 3 This is a partial cross-sectional view of the inner tube structure of the present invention; Figure 4 for Figure 3 Enlarged schematic diagram of the structure at point A; Figure 5 This is a partial cross-sectional view of another embodiment of the present invention; Figure 6 This is a partial cross-sectional view of another embodiment of the present invention; Figure 7 for Figure 6 Enlarged schematic diagram of the structure at point B; Figure 8This is a schematic diagram of the cross-sectional structure of the inner tube of the present invention.
[0030] In the diagram: 1. Shell, 2. End cap, 3. Insulation layer one, 4. Insulating bushing, 5. Inner tube, 501. Metal tube, 502. Insulation layer, 6. Battery stack, 7. End plate, 8. Insulation layer two, 9. Thin tube, 10. Long tube, 11. Outer expansion ring, 12. Explosion-proof diaphragm, 13. Isolation component, 14. Sealing component, 15. Fixing tube, 16. Electric heating component. Detailed Implementation
[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0032] Example 1: Please refer to Figures 1-5 , Figure 8 This embodiment discloses a thermal battery, including an end cap 2, a heat insulation layer 3, an insulating and heat-insulating bushing 4, a battery stack 6, a second heat insulation layer 8, a first terminal block, a second terminal block, an ignition mechanism, and a metal housing 1. One end of the housing 1 is provided with an opening, and the inner wall of the housing 1 is provided with an insulating and heat-insulating bushing 4. The heat insulation layer 3, the battery stack 6, and the second heat insulation layer 8 are arranged sequentially from the inside to the outside in the inner cavity of the housing 1. The opening of the housing 1 is welded and sealed to the edge of the end cap 2. The battery stack 6 is formed by several annular single thermal batteries being connected in series along the axial direction.
[0033] One electrode of the battery stack 6 is electrically connected to the end of terminal 1, and the other electrode of the battery stack 6 is electrically connected to the end of terminal 2. Terminal 1 and terminal 2 both pass through the heat insulation layer 2 and end cover 2 and extend to the outside of the housing 1. Terminal 1 and terminal 2 are both fixed to end cover 2 by insulating seals. The insulating seals are glass sintered insulators, ceramic sealing insulators or polytetrafluoroethylene seals.
[0034] A mounting through hole is provided at the axial center of the battery stack 6. An inner tube 5 is coaxially inserted through the mounting through hole. The outer side of the inner tube 5 is tightly fitted with the inner wall of the inner hole of each individual thermal battery. The inner tube 5 is a hollow insulating tube sealed at both ends. A heating component is provided in the inner cavity of the inner tube 5.
[0035] A single thermal cell includes a ring-shaped positive electrode, a ring-shaped electrolyte sheet, a ring-shaped negative electrode, a ring-shaped current collector, and a ring-shaped heating element. The inner holes of all the single thermal cells are spliced together to form a mounting through hole.
[0036] The ignition mechanism is installed on the end cap 2 or the housing 1. The battery stack 6 is provided with an ignition strip. The flame or heat generated after the ignition mechanism is activated ignites the heating element of the individual thermal battery through the ignition strip. The ignition mechanism is an electric ignition head or a flame cap.
[0037] Preferably, the insulating and heat-insulating bushing 4 includes at least one of mica sheet, ceramic fiber, glass fiber, and aerogel. The insulating and heat-insulating bushing 4 achieves electrical insulation and reduces heat loss. The insulating and heat-insulating bushing 4 has a multi-layer composite structure, with an inner layer of high-temperature resistant insulation and an outer layer of low thermal conductivity insulation. The heat insulation layer 3 is an alumina filler layer, a mica pad, or a ceramic fiber pad.
[0038] Furthermore, such as Figure 8 As shown, the inner tube 5 includes a metal tube 501, and an insulating layer 502 is provided on the outside of the metal tube 501. The insulating layer 502 is an alumina ceramic layer, an enamel coating, a boron nitride coating, a silicon nitride coating, a phosphate coating, or a mica sheet coating. The metal tube 501 is made of stainless steel, a nickel-based alloy, or a titanium alloy.
[0039] Furthermore, the interior of shell 1 is completely sealed, and shell 1 is filled with inert protective gases such as argon and helium to isolate moisture and oxygen from the outside of shell 1.
[0040] The working process and principle of this embodiment are as follows: When the thermal battery is not activated, the battery stack 6 is in a completely sealed environment. The electrolyte sheet is a solid molten salt and does not have ionic conductivity. The positive and negative electrodes of the individual thermal batteries are in an electrically insulated state, and the thermal battery has no power output.
[0041] When the ignition mechanism of the thermal battery receives an external activation signal, the flame or heat generated by the ignition mechanism ignites the heating element of the individual thermal battery through the ignition strip, causing the heating element to undergo an exothermic chemical reaction and release a large amount of heat. When the overall temperature of the battery stack 6 rises to the melting temperature of the electrolyte sheet, the solid electrolyte sheet quickly melts into a liquid state, transforming into a liquid ionic conductor with ionic conductivity. After the electrolyte sheet melts, an electrochemical reaction occurs between the positive and negative electrodes of the individual thermal battery. The electrical energy generated by the electrochemical reaction is collected sequentially through each individual thermal battery to both ends of the battery stack, and then output to the external load through the terminal blocks 1 and 2 that extend through the end cap 2, thus realizing the power supply of the thermal battery.
[0042] In environments close to the lower limit of the operating temperature, the heating component first preheats the battery stack 6 through the inner tube 5 for 10s-500s, raising the temperature of the battery stack 6 and ensuring that the temperature of the battery stack 6 is below the upper limit of the operating temperature of the thermal battery. Then, the battery stack 6 is activated, and the temperature of the battery stack 6 after activation quickly reaches the optimal operating temperature, avoiding problems such as start-up delay, insufficient output power, and inability to activate, and fully meeting the usage requirements of polar, high-altitude, and cryogenic regions.
[0043] In existing technologies, to ensure start-up performance at the lowest operating temperature, the total heat release of the heating agent is often designed to exceed the minimum operating temperature. When the ambient temperature is close to the upper limit of the thermal battery's operating temperature, the ambient heat and the heat released by the heating agent are superimposed, which can easily lead to thermal runaway of the thermal battery. This thermal battery uses central heating in environments close to the lower limit of the operating temperature, which reduces the total amount of heating agent used. The maximum operating temperature inside the battery stack 6 is easy to control, which increases the operating temperature range of this thermal battery. This allows the thermal battery to work reliably for a long time when the ambient temperature is close to the upper and lower limits of the thermal battery's operating temperature. The reduction in the amount of heating agent used further reduces the overall weight of this thermal battery.
[0044] This thermal battery solves the contradiction between the slow heating and poor output of the low-temperature electrolyte and the high risk of thermal runaway of the high-temperature electrode in existing thermal batteries, thus improving the reliability of this thermal battery over a wide operating temperature range.
[0045] Example 2: Figure 3 As shown, this embodiment discloses a thermal battery, whose structure is roughly the same as that of Embodiment 1. The difference is that the heating component in this embodiment is a long tube 10 with both ends closed inside the inner tube 5. Several protrusions are fixed on the outside of the long tube 10 against the inner wall of the inner tube 5. The protrusions are ceramic sheets or metal sheets.
[0046] The long tube 10 is filled with an exothermic agent. An electric igniter, which is commonly used in the prior art, is installed on the long tube 10. The wire of the electric igniter passes through the long tube 10, the heat insulation layer 8, the end cap 2 and extends to the outside of the housing 1. The electric igniter on the long tube 10 is electrically connected to an external control switch through the wire.
[0047] Furthermore, the exothermic agent is potassium perchlorate iron exothermic agent, aluminothermic agent, or potassium borate nitrate exothermic agent.
[0048] The working process and principle of this embodiment are as follows: The protrusions prevent the long tube 10 from directly contacting the inner tube 5, reducing the speed of heat movement between the heating components and the battery stack. The protrusions also prevent the long tube 10 from moving inside the inner tube 5.
[0049] After the exothermic agent inside the long tube 10 is activated, the temperature of the long tube 10 exceeds 200°C. The heat from the exothermic agent inside the long tube 10 is transferred to the battery stack 6 through heat transfer and heat radiation.
[0050] In an environment close to the lower limit of the operating temperature, i.e., when the ambient temperature is within the first third of the operating temperature range, the temperature of the exothermic agent in the long tube 10 after activation exceeds 200°C. The heat from the exothermic agent in the long tube 10 is transferred to the battery stack 6 through heat transfer and heat radiation.
[0051] In environments other than the minimum operating temperature, i.e., when the ambient temperature is within the latter two-thirds of the operating temperature range, the exothermic agent in the long tube 10 and the heating element of the battery stack 6 are activated synchronously, or the exothermic agent in the long tube 10 is activated later than the heating element of the battery stack 6, and the temperature of the exothermic agent in the long tube 10 after activation is not higher than the temperature of the heating element in the battery stack 6 after activation.
[0052] Example 3: Figure 5 As shown, this embodiment discloses a thermal battery, whose structure is roughly the same as that of Embodiment 1. The difference is that the heating component in this embodiment is an electric heating element 16 that is attached to the inner wall of the inner tube 5. The wire of the electric heating element 16 passes through the long tube 10, the second heat insulation layer 8, the end cap 2 and extends to the outside of the shell 1. The electric heating element 16 is an electric heating wire with a temperature control switch or an electric heating plate with a temperature control switch. The electric heating element 16 is electrically connected to an external control switch through the wire.
[0053] The working process and principle of this embodiment are as follows: In an environment close to the lower limit of the operating temperature, i.e., when the ambient temperature is within the first third of the operating temperature range, the electric heating element 16 is energized to generate heat. The electric heating element 16 preheats the battery stack 6 through the inner tube 5, raising the temperature of the battery stack 6. The temperature of the battery stack 6 is then lower than the upper limit of the operating temperature of the thermal battery. The battery stack 6 is then activated, and the temperature of the activated battery stack 6 quickly reaches the optimal operating temperature.
[0054] Example 4: Figures 2-5 , Figure 8 As shown, this embodiment discloses a thermal battery. Based on any of the embodiments from embodiment one to embodiment three, the length of the inner tube 5 in this embodiment is greater than the axial thickness of the battery stack 6. Both ends of the inner tube 5 extend into the insulation layer 1 3 and the insulation layer 2 8, respectively, so that the inner tube 5 can serve as the central positioning axis of the battery stack 6 to resist radial impact. At least one axial end of the inner tube 5 is sealed by installing an explosion-proof diaphragm 12. The end of the inner tube 5 with the explosion-proof diaphragm 12 extends to the outside of the mounting through hole of the battery stack 6.
[0055] The pressure difference between the air inside the shell 1 and the air pressure inside the inner tube 5 is greater than 50.0 kPa.
[0056] The working process and principle of this embodiment are as follows: When this thermal battery is working normally, the explosion-proof diaphragm 12 maintains the seal inside the inner tube 5 and maintains the negative pressure inside the inner tube 5. When the battery stack 6 reacts abnormally and the gas pressure inside the casing 1 exceeds the limit pressure, the explosion-proof diaphragm 12 will rupture. The gas generated by the battery stack 6 will enter the long tube 10 through the ruptured explosion-proof diaphragm 12, preventing damage to the casing 1. The pressure relief is without open flame or liquid splashing, making it suitable for sealed compartments and places with high fire protection requirements.
[0057] Preferably, one end of the metal tube 501 has a radially outwardly extending metal expansion ring 11. The expansion ring 11 is located between the battery stack 6 and the heat insulation layer 3. The expansion ring 11 is electrically connected to one electrode of the battery stack 6, and the other electrode of the battery stack 6 is electrically connected to the end of the terminal block 1. The position of the metal tube 501 away from the expansion ring 11 is electrically connected to the end of the terminal block 2. Both the terminal block 1 and the terminal block 2 pass through the heat insulation layer 2 and the end cap 2 and extend to the outside of the housing 1. By using the inner tube 5 and the expansion ring 11 as current collectors, the internal electron transmission path is shortened, the internal resistance of the thermal battery is reduced, the discharge capability of the thermal battery to cope with pulsed high current is improved, and the space for setting up a separate current collector is saved.
[0058] Example 5: Figures 2-4 As shown, this embodiment discloses a thermal battery, whose structure is roughly the same as that of embodiment four. The difference is that in this embodiment, the heat insulation layer 2 8 is provided with a rigid thin tube 9. One end of the thin tube 9 is close to the insulating heat insulation bushing 4, and the other end of the thin tube 9 is close to the explosion-proof diaphragm 12.
[0059] The working process and principle of this embodiment are as follows: When the battery stack 6 reacts abnormally and the gas pressure inside the casing 1 exceeds the limit pressure, the overpressured gas is quickly guided to the vicinity of the explosion-proof diaphragm 12 through the insulating and heat-insulating bushing 4 and the thin tube 9, thereby improving the explosion-proof and flame-retardant performance of this thermal battery.
[0060] Example 6: Figure 2 , Figure 3 , Figure 5 As shown, this embodiment discloses a thermal battery, whose structure is roughly the same as that of Embodiment 1. The difference is that, in this embodiment, one end of the inner tube 5 extends radially outward with an outer expansion ring 11, which is located between the battery stack 6 and the first insulation layer 3. An end plate 7 is provided between the battery stack 6 and the second insulation layer 8. The second insulation layer 8 is a mica pad or a ceramic fiber pad, and the end plate 7 is a ceramic plate or a metal plate.
[0061] Furthermore, the end plate 7 is coaxially fixed to the inner tube 5.
[0062] The working process and principle of this embodiment are as follows: The inner tube 5 provides radial constraint for each individual thermal cell, preventing misalignment of the individual thermal cells caused by vibration and impact. The end plate 7 and the outer expansion ring 11 facilitate the application of axial preload to the battery stack 6, compensating for the thermal expansion and sintering shrinkage of the battery stack 6 at high temperatures, and preventing gaps between adjacent individual thermal cells.
[0063] Example 7: Figures 2-5 As shown, this embodiment discloses a thermal battery, including a housing 1, an end cap 2, a heat insulation layer 3, an insulating and heat-insulating bushing 4, a battery stack 6, a second heat insulation layer 8, a first terminal and a second terminal. One end of the housing 1 is provided with an opening, and the inner wall of the housing 1 is provided with an insulating and heat-insulating bushing 4. The heat insulation layer 3, the battery stack 6 and the second heat insulation layer 8 are arranged sequentially from the inside to the outside in the inner cavity of the housing 1. The opening of the housing 1 is welded and sealed to the edge of the end cap 2. The battery stack 6 is formed by stacking several individual thermal batteries in series along the axial direction.
[0064] A mounting through hole is provided at the axial center of the battery stack 6. An inner tube 5 is coaxially inserted through the mounting through hole. The outer side of the inner tube 5 is tightly fitted with the inner wall of the inner hole of each individual thermal battery. Both ends of the inner tube 5 are sealed.
[0065] The inner tube 5 includes a metal tube 501, an insulating layer 502 is provided on the outside of the metal tube 501, and a metal expansion ring 11 extends radially outward from one end of the metal tube 501. The expansion ring 11 is located between the battery stack 6 and the heat insulation layer 3.
[0066] Among them, the outer expansion ring 11 is electrically connected to one electrode of the battery stack 6, the other electrode of the battery stack 6 is electrically connected to the end of the terminal 1, the metal tube 501 is electrically connected to the end of the terminal 2 away from the outer expansion ring 11, and both the terminal 1 and the terminal 2 pass through the heat insulation layer 2 8 and the end cap 2 and extend to the outside of the housing 1.
[0067] The working process and principle of this embodiment are as follows: Existing thermal batteries mainly draw leads from the edge or top and bottom of the cell, resulting in large internal resistance losses during high-current discharge.
[0068] This thermal battery uses the inner tube 5 as a current collector, which shortens the internal electron transmission path, reduces the internal resistance of the thermal battery, improves the thermal battery's ability to cope with pulsed high current discharge, and saves space for setting up a separate current collector.
[0069] Example 8: Figure 2 and Figure 5 As shown, this embodiment discloses a thermal battery, whose structure is roughly the same as that of Embodiment 7. The difference is that the length of the inner tube 5 in this embodiment is greater than the axial thickness of the battery stack 6, and at least one axial end of the inner tube 5 is sealed by installing an explosion-proof diaphragm 12.
[0070] The pressure difference between the air inside the shell 1 and the air pressure inside the inner tube 5 is greater than 50 kPa.
[0071] The working process and principle of this embodiment are as follows: When this thermal battery is working normally, the explosion-proof diaphragm 12 maintains the seal inside the inner tube 5 and maintains the negative pressure inside the inner tube 5. When the battery stack 6 reacts abnormally and the gas pressure inside the casing 1 exceeds the limit pressure, the explosion-proof diaphragm 12 ruptures. The gas generated by the battery stack 6 enters the long tube 10 through the ruptured explosion-proof diaphragm 12, preventing damage to the casing 1. The pressure relief is without open flame or liquid splashing, making it suitable for sealed chambers and places with high fire protection requirements.
[0072] Example 9: Figure 6 and Figure 7 As shown, this embodiment discloses a thermal battery, including a housing 1, an end cap 2, a heat insulation layer 3, an insulating and heat-insulating bushing 4, a battery stack 6, and a second heat insulation layer 8. One end of the housing 1 is provided with an opening, and the inner wall of the housing 1 is provided with an insulating and heat-insulating bushing 4. The heat insulation layer 3, the battery stack 6, and the second heat insulation layer 8 are arranged sequentially from the inside to the outside in the inner cavity of the housing 1. The opening of the housing 1 is welded and sealed to the edge of the end cap 2. The battery stack 6 is formed by stacking several individual thermal batteries in series along the axial direction.
[0073] An installation hole is provided in the middle of the end cap 2, and an installation through hole is provided at the axial center of the battery stack 6. An insulating inner tube 5 is coaxially inserted in the installation through hole. The outer side of the inner tube 5 is tightly fitted with the inner wall of the inner hole of each individual thermal battery. One end of the inner tube 5 near the bottom of the inner cavity of the shell 1 is closed. A fixing tube 15 is fixedly installed at the other end of the inner tube 5. The fixing tube 15 passes through the heat insulation layer 2 8 and the end cap 2 and is fixedly connected to the installation hole. A sealing element 14 is installed in the fixing tube 15. The sealing element 14 is a metal block, a ceramic block or a glass block.
[0074] The fixed tube 15 is a mica tube, ceramic tube or glass tube, and the inner tube 5 has a heating component in its inner cavity.
[0075] The heating component is placed inside the inner tube 5, and then the sealing component 14 is installed on the fixed tube 15.
[0076] The heating component is a heated medicine pack or an electric heating element in the prior art, and the electric heating element is an electric heating wire or an electric heating rod.
[0077] The working process and principle of this embodiment are as follows: When the ambient temperature is close to the lower limit of the operating temperature of the thermal battery, the heating component first preheats the battery stack 6 through the inner tube 5, raising the temperature of the battery stack 6. The temperature of the battery stack 6 is lower than the upper limit of the operating temperature of the thermal battery. Then the battery stack 6 is activated. After activation, the temperature of the battery stack 6 quickly reaches the optimal operating temperature, avoiding problems such as start-up delay, insufficient output power, and inability to activate.
[0078] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.
Claims
1. A thermal battery, characterized in that: Includes a housing (1) and an end cap (2). One end of the housing (1) is provided with an opening. An insulating heat-insulating bushing (4) is provided on the inner wall of the housing (1). In the inner cavity of the housing (1), a heat insulation layer one (3), a battery stack (6) and a heat insulation layer two (8) are arranged sequentially from the inside to the outside. The opening of the housing (1) is fixedly connected to the end cap (2). The battery stack (6) is composed of several individual thermal batteries stacked sequentially along the axial direction. The battery stack (6) has an axial center hole for mounting, and an inner tube (5) is coaxially inserted in the mounting hole. The outer side of the inner tube (5) is tightly fitted with the inner wall of the inner hole of each individual thermal battery. The inner tube (5) is a hollow insulating tube sealed at both ends, and a heating component is provided in the inner cavity of the inner tube (5).
2. The thermal battery according to claim 1, characterized in that: The heating component is a long tube (10) located inside the inner tube (5), and the outer side of the long tube (10) is provided with a number of protrusions that abut against the inner wall of the inner tube (5). The long tube (10) is filled with an exothermic agent. An electric ignition head is installed on the long tube (10). The wire of the electric ignition head passes through the long tube (10), the second heat insulation layer (8), the end cap (2), and extends to the outside of the shell (1).
3. The thermal battery according to claim 1, characterized in that: The heating component is an electric heating element (16) that is attached to the inner wall of the inner tube (5). The wires of the electric heating element (16) pass through the long tube (10), the second heat insulation layer (8), the end cap (2) and extend to the outside of the shell (1).
4. The thermal battery according to any one of claims 1-3, characterized in that: The length of the inner tube (5) is greater than the axial thickness of the battery stack (6). At least one axial end of the inner tube (5) is sealed by installing an explosion-proof diaphragm (12). The end of the inner tube (5) with the explosion-proof diaphragm (12) extends to the outside of the mounting through hole of the battery stack (6). The pressure difference between the air pressure inside the shell (1) and the air pressure inside the inner tube (5) is greater than 50.0 kPa.
5. The thermal battery according to claim 4, characterized in that: The second heat insulation layer (8) is provided with a thin tube (9), one end of the thin tube (9) is close to the insulating heat insulation bushing (4), and the other end of the thin tube (9) is close to the explosion-proof diaphragm (12).
6. The thermal battery according to claim 1, characterized in that: The inner tube (5) includes a metal tube (501), and an insulating layer (502) is provided on the outside of the metal tube (501). The insulating layer (502) is an alumina ceramic layer, an enamel coating, a boron nitride coating, a silicon nitride coating, a phosphate coating, or a mica sheet coating.
7. The thermal battery according to claim 1, characterized in that: One end of the inner tube (5) extends radially outward with an outer expansion ring (11), which is located between the battery stack (6) and the first heat insulation layer (3). An end plate (7) is provided between the battery stack (6) and the second heat insulation layer (8).
8. A thermal battery, characterized in that: The device includes a housing (1), an end cap (2), a first terminal block and a second terminal block. One end of the housing (1) has an opening. An insulating heat-insulating bushing (4) is provided on the inner wall of the housing (1). The inner cavity of the housing (1) is provided with a heat insulation layer (3), a battery stack (6) and a second heat insulation layer (8) arranged sequentially from the inside to the outside. The opening of the housing (1) is fixedly connected to the end cap (2). The battery stack (6) is composed of several individual thermal batteries stacked sequentially along the axial direction. The battery stack (6) has an axial center hole for mounting, and an inner tube (5) is coaxially inserted in the mounting hole. The outer side of the inner tube (5) is tightly fitted with the inner hole wall of each individual thermal battery, and both ends of the inner tube (5) are sealed. The inner tube (5) includes a metal tube (501), and an insulating layer (502) is provided on the outside of the metal tube (501). One end of the metal tube (501) extends radially outward with an outer expansion ring (11) made of metal material. The outer expansion ring (11) is located between the battery stack (6) and the heat insulation layer (3). The outer expansion ring (11) is electrically connected to one electrode of the battery stack (6), the other electrode of the battery stack (6) is electrically connected to the end of terminal one, the metal tube (501) is electrically connected to the end of terminal two away from the outer expansion ring (11), and both terminal one and terminal two pass through the heat insulation layer two (8) and the end cap (2) and extend to the outside of the housing (1).
9. The thermal battery according to claim 8, characterized in that: The length of the inner tube (5) is greater than the axial thickness of the battery stack (6), and at least one axial end of the inner tube (5) is sealed by installing an explosion-proof diaphragm (12). The pressure difference between the air pressure inside the shell (1) and the air pressure inside the inner tube (5) is greater than 50 kPa.
10. A thermal battery, characterized in that: Includes a housing (1) and an end cap (2). One end of the housing (1) is provided with an opening. An insulating heat-insulating bushing (4) is provided on the inner wall of the housing (1). In the inner cavity of the housing (1), a heat insulation layer one (3), a battery stack (6) and a heat insulation layer two (8) are arranged sequentially from the inside to the outside. The opening of the housing (1) is fixedly connected to the end cap (2). The battery stack (6) is composed of several individual thermal batteries stacked sequentially along the axial direction. An installation hole is provided in the middle of the end cap (2), and an installation through hole is provided at the axial center of the battery stack (6). An insulating inner tube (5) is coaxially inserted in the installation through hole. The outer side of the inner tube (5) is tightly fitted with the inner wall of the inner hole of each individual thermal battery. One end of the inner tube (5) near the bottom of the inner cavity of the shell (1) is closed. A fixing tube (15) is fixedly installed at the other end of the inner tube (5). The fixing tube (15) passes through the second heat insulation layer (8) and the end cap (2) and is fixedly connected to the installation hole. A sealing component (14) is installed inside the fixing tube (15). The fixed tube (15) is a mica tube, ceramic tube or glass tube, and the inner tube (5) is provided with a heating component in its inner cavity.