Heat pipe and battery with inertable electrolyte

Abstract

The application provides a heat pipe and a battery capable of inactivating electrolyte, and belongs to the technical field of energy storage batteries. The heat pipe comprises a heat pipe body and a containing cavity connected with the heat pipe body. A heat-conducting inactivation medium is filled in the containing cavity, and the heat-conducting inactivation medium is used for inactivating electrolyte when thermal runaway of the battery occurs. A pressure breakthrough is arranged on the containing cavity. The application inactivates the electrolyte by making the heat-conducting inactivation medium and the electrolyte undergo saponification reaction, prevents the battery from further heating, and achieves the purpose of inhibiting thermal runaway. The application can effectively prevent the occurrence of fire or explosion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of energy storage batteries, and relates to the safety technology of energy storage batteries, in particular to a heat pipe and battery capable of inactivating electrolyte. BACKGROUND

[0002] In recent years, with the wide application of lithium batteries, more and more attention has been paid to the safety problems of lithium batteries. Short circuit of the battery, overcharge of the battery when the maximum current or maximum voltage is exceeded, decomposition of the electrolyte when the battery is exposed to a high temperature environment, etc. can all cause high pressure and high temperature gas to be generated inside the battery, causing the shell of the battery to deform, shortening the service life of the battery, and in severe cases, causing fire or explosion.

[0003] The electrolyte of a general lithium battery is usually a mixed solution formed by dissolving lithium hexafluorophosphate in a non-aqueous solvent, wherein the non-aqueous solvent is mainly ester substances such as ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, propylene carbonate and diethyl carbonate. It is shown in the article "Research on the thermal stability of lithium battery electrolyte" that the electrolyte will change when the temperature reaches 60-85℃, and lithium hexafluorophosphate will undergo endothermic decomposition when the temperature is higher than 150℃, and the endothermic decomposition rate reaches the maximum at 225℃. As the temperature inside the battery continues to rise, the electrolyte will decompose, causing the battery to lose control, and the high pressure and high temperature gas generated by the decomposition poses a safety hazard. At present, the inhibition of the decomposition of high pressure and high temperature gas is mainly by spraying fire extinguishing agent into the electrolyte cavity to prevent the battery from catching fire, but this method cannot fundamentally control the continuous decomposition and generation of high pressure and high temperature gas when the battery loses control, and the battery still has the risk of explosion. SUMMARY

[0004] In view of the problem that the existing technology cannot fundamentally control the continuous decomposition and generation of high pressure and high temperature gas when the battery loses control, and the battery has the risk of explosion, the present application provides a heat pipe and battery capable of inactivating electrolyte.

[0005] The present application fills the containing cavity with a heat-conducting inactivation medium, which not only transfers the heat generated by the battery during normal operation to the evaporation section of the heat pipe, but also releases the heat-conducting inactivation medium from the containing cavity under the pressure of the gas generated by the thermal runaway to react with the electrolyte and inactivate the electrolyte, thereby inhibiting the thermal runaway and effectively preventing the occurrence of fire or explosion.

[0006] A heat pipe capable of inactivating electrolyte, comprising a heat pipe body and a containing cavity connected to the heat pipe body; the containing cavity is filled with a heat-conducting inactivation medium, which is used to inactivate the electrolyte when the battery loses control; a pressure breakthrough opening is arranged on the containing cavity.

[0007] Further limited, the heat-conducting inerting medium is ammonia, saturated sodium hydroxide solution, saturated potassium hydroxide solution, sodium methoxide alcohol solution, sodium ethoxide alcohol solution or sodium tert-butoxide alcohol solution.

[0008] Further limited, the heat pipe body is provided with a heat-conducting working medium and a wick, the heat-conducting working medium is a heat-inerting medium, and a liquid surface of the heat-conducting inerting medium in the containing cavity is in contact with the wick of the heat pipe body.

[0009] Further limited, the pressure breakthrough opening is provided with a sealing assembly.

[0010] Further limited, the pressure breakthrough opening is arranged on the upper surface of the containing cavity; and the containing cavity is a disc-shaped cavity structure or a square cavity structure.

[0011] Further limited, the sealing assembly is a thin-walled annular groove, a blast-resistant membrane or a fusible metal piece.

[0012] Further limited, the wick in the heat pipe body is a single-layer mesh wick, a multi-layer mesh wick, a sintered powder wick or an axial channel wick.

[0013] A battery comprises a battery cell and the heat pipe of the inertable electrolyte as described above, and the battery cell is connected with the heat pipe body and the containing cavity.

[0014] Further limited, the battery cell is a wound battery cell, the electrode sheet of the wound battery cell is wrapped around the outside of the heat pipe body, and the wound battery cell is placed on the containing cavity and supported by the containing cavity.

[0015] Further limited, the battery cell is a square battery cell, a plurality of heat pipe bodies are distributed on the outside of the square battery cell, and the plurality of heat pipe bodies are in contact with the square battery cell, the square battery cell is placed on the containing cavity and supported by the containing cavity.

[0016] Further limited, the battery further comprises a battery box, an inner cavity of the battery box is an electrolyte cavity, the containing cavity and the battery cell are placed in the electrolyte cavity, the evaporation section of the heat pipe body is placed in the electrolyte cavity, the condensation section penetrates through the battery box and is placed outside the electrolyte cavity, and the sum of the filling amount of the heat-conducting inerting medium in the heat pipe body and the filling amount of the heat-conducting inerting medium in the containing cavity is greater than or equal to twice the filling amount of the electrolyte in the electrolyte cavity.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] 1. The heat pipe of the present application can inactivate electrolyte, which comprises a heat pipe body and a containing cavity connected with the heat pipe body, and a heat-conducting inactivation medium is filled in the containing cavity, and a pressure breakthrough is arranged on the containing cavity. The heat-conducting inactivation medium in the containing cavity can conduct the heat generated by the battery to the heat pipe body when the battery works normally, and the heat is conducted out and cooled by the heat pipe body. If the battery is in thermal runaway, the gas pressure in the electrolyte cavity will open the pressure breakthrough, and the heat-conducting inactivation medium in the containing cavity will be released into the electrolyte cavity along the pressure breakthrough, and a saponification reaction will occur between the heat-conducting inactivation medium and the electrolyte in the electrolyte cavity. The heat-conducting inactivation medium is an alkali substance, and the non-aqueous solvent in the electrolyte is an ester substance, and a saponification reaction occurs between them to generate solid carboxylate. The content of the non-aqueous solvent in the electrolyte is generally 80-90%, and the non-aqueous solvent will decompose at high temperature to generate flammable gas. The saponification reaction makes the viscosity of the electrolyte larger, or solidifies the electrolyte, destroys the balance of the electrolyte solution, and makes the positive and negative ions in the electrolyte migrate slowly or stop migrating. Without the non-aqueous solvent to decompose gas, the purpose of inhibiting thermal runaway is achieved, and the occurrence of fire or explosion can be effectively prevented.

[0019] 2. The heat-conducting inactivation medium of the present application is ammonia water, saturated sodium hydroxide solution, saturated potassium hydroxide solution, sodium methoxide alcohol solution, sodium ethoxide alcohol solution or sodium tert-butoxide alcohol solution. Water and alcohol substances can meet the requirements of the medium, and these substances are all alkali substances and can meet the requirements of saponification reaction.

[0020] 3. A sealing assembly is arranged at the pressure breakthrough, and the sealing assembly can only open the pressure breakthrough when the gas pressure in the electrolyte cavity reaches the limit. The pressure breakthrough is in a sealed state when the battery works normally, preventing the heat-conducting inactivation medium from leaking and affecting the battery work.

[0021] 4. A battery of the present application comprises a battery cell and the heat pipe of the present application, and the battery cell is connected with the heat pipe body and the containing cavity. If the battery cell is a wound battery cell, the electrode sheet of the wound battery cell is wrapped around the outside of the heat pipe body. This arrangement can efficiently conduct the heat generated by the battery cell when it works, and can support the wound battery cell by the heat pipe body. The wound battery cell is placed on the containing cavity, and the containing cavity can support the wound battery cell. If the battery cell is a square battery cell, a plurality of heat pipe bodies are arranged on the outside of the square battery cell, and the plurality of heat pipe bodies are in contact with the square battery cell. The plurality of heat pipe bodies can conduct the heat generated by the battery cell when it works, and can improve the heat dissipation efficiency of the square battery cell. The square battery cell is placed on the containing cavity, and the containing cavity can support the square battery cell.

[0022] 5. The battery according to any one of the preceding battery, further comprising a battery box, an inner cavity of the battery box is an electrolyte cavity, and a sum of a filling amount of the heat-conducting inerting medium in the heat pipe body and a filling amount of the heat-conducting inerting medium in the containing cavity is greater than or equal to twice a filling amount of the electrolyte in the electrolyte cavity, so that the heat-conducting inerting medium can fully react with the electrolyte, the electrolyte can be completely inerted in a short time, and the control efficiency of the battery thermal runaway is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 a structure diagram of the heat pipe of Example 1;

[0024] Figure 2 a structure diagram of the heat pipe of Example 2;

[0025] Figure 3 a structure diagram of the heat pipe of Example 3;

[0026] wherein 1 is a heat pipe body, 2 is a containing cavity, 3 is a thin-walled annular groove, 4 is a burst membrane, and 5 is a fusible metal piece. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be further explained and described below in combination with the drawings and examples, but the present application is not limited to the following described embodiments.

[0028] The heat pipe for inerting electrolyte provided by the present application comprises a heat pipe body 1 and a containing cavity 2 connected with the heat pipe body 1, the containing cavity 2 is filled with heat-conducting inerting medium, the heat-conducting inerting medium is used for inerting electrolyte when the battery occurs thermal runaway, and a pressure breakthrough is arranged on the containing cavity 2. The heat-conducting inerting medium is ammonia water, a saturated sodium hydroxide solution, a saturated potassium hydroxide solution, a sodium methoxide alcohol solution, a sodium ethoxide alcohol solution or a sodium tert-butoxide alcohol solution. The heat-conducting working medium in the heat pipe body 1 is the heat-conducting inerting medium, a liquid surface of the heat-conducting inerting medium in the containing cavity 2 is in contact with a wick of the heat pipe body 1. A sealing assembly is arranged at the pressure breakthrough. The pressure breakthrough is arranged on an upper surface of the containing cavity 2, the containing cavity 2 has a disc-shaped cavity structure or a square cavity structure. The sealing assembly is a thin-walled annular groove 3, a burst membrane 4 or a fusible metal piece 5. The wick in the heat pipe body 1 is a single-layer mesh core, a multi-layer mesh core, a sintered powder tube core or an axial groove type tube core.

[0029] The wick of the present application is arranged in a steam flow cavity of the heat pipe body, the heat-conducting medium, i.e. the heat-conducting inerting medium, is filled in a condensate reflux cavity of the heat pipe body, and continuously circulates between the steam flow cavity and the condensate reflux cavity.

[0030] This invention discloses a battery comprising a battery cell and a heat pipe containing an inert electrolyte, wherein the battery cell is connected to both a heat pipe body 1 and a receiving cavity 2. The battery cell is a wound cell, with its electrode plates wrapped around the outside of the heat pipe body 1, and is placed on the receiving cavity 2, which supports the wound cell. Alternatively, the battery cell may be a square cell, with multiple heat pipe bodies 1 distributed around its outer side, all in contact with the square cell. The square cell is placed on the receiving cavity 2, which supports the square cell. The battery also includes a battery case, the inner cavity of which is an electrolyte chamber, and the housing 2 and the battery cell are both placed inside the electrolyte chamber; the evaporation section of the heat pipe body 1 is placed inside the electrolyte chamber, and the condensation section passes through the battery case and is placed outside the electrolyte chamber; the sum of the amount of thermally conductive inert medium in the heat pipe body 1 and the amount of thermally conductive inert medium in the housing 2 is greater than or equal to twice the amount of electrolyte in the electrolyte chamber.

[0031] Example 1

[0032] See Figure 1 This embodiment of a heat pipe capable of inertizing electrolyte includes a heat pipe body 1 and a receiving cavity 2 connected to the heat pipe body 1. The inner cavity of the heat pipe body 1 is filled with a thermally conductive inertizing medium. A pressure puncture port is provided on the upper end face of the receiving cavity 2, which is a weak point located on the receiving cavity 2. The thermally conductive working medium in the heat pipe body 1 is a thermally conductive inertizing medium, and the liquid surface of the thermally conductive inertizing medium in the receiving cavity 2 is in contact with the liquid wick of the heat pipe body 1. That is, the receiving cavity of the receiving cavity 2 is connected to the condensate return cavity and the vapor flow cavity of the evaporation section of the heat pipe body 1. The thermally conductive inertizing medium is used to inertize the electrolyte when the battery experiences thermal runaway.

[0033] In this embodiment, a sealing component is provided at the pressure breakthrough point to seal the pressure breakthrough point and prevent leakage of the thermally conductive inert medium, which would affect the normal operation of the electrolyte.

[0034] Preferably, in this embodiment, the sealing component is a thin-walled annular groove 3 surrounding the outer side of the heat pipe body 1. The wall thickness of the annular thin-walled groove 3 is one-third of the wall thickness of the receiving cavity 2, which enables the gas pressure in the electrolyte cavity to reach 0.5MPa, thereby opening the pressure breach and releasing the thermally conductive inert medium in the receiving cavity 2.

[0035] It should be noted that the pressure breakthrough point in this embodiment can be provided not only on the upper end face of the receiving cavity 2, but also on the side end face of the receiving cavity 2.

[0036] Preferably, the receiving cavity 2 in this embodiment has a disc-shaped cavity structure.

[0037] Preferably, the liquid-absorbing core inside the heat pipe body 1 in this embodiment is a multi-layer mesh core.

[0038] Preferably, the thermally conductive inertizing medium in this embodiment is a saturated sodium hydroxide solution.

[0039] Example 2

[0040] See Figure 2 This embodiment of the heat pipe for inertizing electrolyte differs from Embodiment 1 in that the sealing component in this embodiment is a pressure relief membrane 4 disposed at the pressure breakthrough point. The pressure relief membrane 4 is disposed at the center of the upper end face of the receiving cavity 2, and the thickness of the pressure relief membrane 4 is 0.3 mm. It can make the gas pressure in the electrolyte cavity reach 0.5 MPa, which can open the pressure breakthrough point and release the thermally conductive inertizing medium in the receiving cavity 2.

[0041] Preferably, the receiving cavity 2 in this embodiment has a square cavity structure.

[0042] Preferably, the liquid-absorbing core inside the heat pipe body 1 in this embodiment is a sintered powder core.

[0043] Preferably, the thermally conductive inertizing medium in this embodiment is a saturated potassium hydroxide solution.

[0044] Everything else is the same as in Example 1.

[0045] Example 3

[0046] See Figure 3 This embodiment of the heat pipe with inert electrolyte differs from Embodiment 1 in that the sealing component in this embodiment is a fusible metal part 5 disposed on one side of the heat pipe body 1. The fusible metal part 5 is disposed on the upper end face of the receiving cavity 2. The fusible metal part 5 can dissolve when the temperature inside the electrolyte cavity reaches 150°C, thereby opening the receiving cavity and releasing the thermally conductive inert medium inside the receiving cavity 2.

[0047] Preferably, the fusible metal component 5 in this embodiment is a fusible metal sheet.

[0048] Preferably, the receiving cavity 2 in this embodiment has a square cavity structure.

[0049] Preferably, the liquid-absorbing core inside the heat pipe body 1 in this embodiment is an axially channeled core.

[0050] Preferably, the thermally conductive inertizing medium in this embodiment is a sodium methoxide alcohol solution.

[0051] Everything else is the same as in Example 1.

[0052] In addition to the substances described in the above embodiments, the thermally conductive inertizing medium of the present invention can also be ammonia, sodium ethoxide alcohol solution, or sodium tert-butoxide alcohol solution. The electrolyte inertization of the present invention involves a saponification reaction between the thermally conductive inertizing medium and the electrolyte (the thermally conductive inertizing medium is an alkaline substance, and the non-aqueous solvent in the electrolyte is an ester substance, and a saponification reaction occurs between the two). This increases the viscosity of the electrolyte or solidifies the electrolyte, disrupting the equilibrium environment of the electrolyte solution and causing the migration of positive and negative ions in the electrolyte to slow down or stop, thereby preventing further heating of the battery and suppressing thermal runaway. The liquid-absorbing core inside the heat pipe body 1 of the present invention can also be a single-layer mesh core.

[0053] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments, and is not intended to limit the present invention. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be considered to fall within the patent protection scope defined by the submitted claims.

Claims

1. A battery, characterized in that, It includes a heat pipe, a battery cell, and a battery case; the heat pipe includes a heat pipe body and a receiving cavity connected to the heat pipe body; the receiving cavity is filled with a thermally conductive inert medium, which is used to inert the electrolyte when the battery experiences thermal runaway; the receiving cavity is provided with a pressure rupture port; The thermally conductive inert medium is ammonia, a saturated sodium hydroxide solution, a saturated potassium hydroxide solution, a sodium methoxide alcohol solution, a sodium ethoxide alcohol solution, or a sodium tert-butoxide alcohol solution. The heat pipe body is provided with a heat-conducting working medium and a liquid wick. The heat-conducting working medium is a heat-conducting inert medium. The liquid surface of the heat-conducting inert medium in the receiving cavity is in contact with the liquid wick of the heat pipe body. The inner cavity of the battery box is an electrolyte cavity, and both the housing and the battery cell are placed inside the electrolyte cavity; the battery cell is connected to both the heat pipe body and the housing cavity; The evaporation section of the heat pipe body is placed inside the electrolyte chamber, and the condensation section passes through the battery box and is placed outside the electrolyte chamber; the sum of the amount of thermally conductive inert medium in the heat pipe body and the amount of thermally conductive inert medium in the containing chamber is greater than or equal to twice the amount of electrolyte in the electrolyte chamber. The battery cell is a wound battery cell, with the electrode sheets of the wound battery cell wrapped around the outside of the heat pipe body, and the wound battery cell is placed on the receiving cavity, which supports the wound battery cell. Alternatively, the battery cell is a square battery cell, with multiple heat pipe bodies distributed on the outer side of the square battery cell, and all of the multiple heat pipe bodies are in contact with the square battery cell. The square battery cell is placed on a receiving cavity, and the receiving cavity supports the square battery cell. When the battery cell is working normally, the thermally conductive inert medium inside the cavity conducts the heat generated by the battery cell to the heat pipe body, and the heat is then discharged and cooled through the heat pipe body. If thermal runaway occurs in the battery, the gas pressure generated in the electrolyte chamber will open the pressure vent. The thermally conductive inert medium in the containment chamber will be released into the electrolyte chamber along the pressure vent and undergo a saponification reaction with the electrolyte in the electrolyte chamber. After the saponification reaction, the viscosity of the electrolyte increases or the electrolyte solidifies, which disrupts the equilibrium environment of the electrolyte solution. This causes the migration of positive and negative ions in the electrolyte to slow down or stop, thereby suppressing the occurrence of thermal runaway and effectively preventing fire or explosion.

2. The battery as described in claim 1, characterized in that, A sealing component is provided at the pressure breach point.

3. A battery as described in claim 2, characterized in that, The pressure breakthrough point is located on the upper surface of the receiving cavity; the receiving cavity is a disc-shaped cavity structure or a square cavity structure.

4. A battery as described in claim 3, characterized in that, The sealing component is a thin-walled annular groove, a venting membrane, or a fusible metal part.

5. A battery as described in claim 4, characterized in that, The liquid-absorbing core inside the heat pipe body is a single-layer mesh core, a multi-layer mesh core, a sintered powder core, or an axial channel core.

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