CN107615568B - Battery pack - Google Patents
Battery pack Download PDFInfo
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- CN107615568B CN107615568B CN201580079443.7A CN201580079443A CN107615568B CN 107615568 B CN107615568 B CN 107615568B CN 201580079443 A CN201580079443 A CN 201580079443A CN 107615568 B CN107615568 B CN 107615568B
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- water
- absorbing polymer
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- battery
- liquid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/659—Means for temperature control structurally associated with the cells by heat storage or buffering, e.g. heat capacity or liquid-solid phase changes or transition
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides a battery pack, which comprises a battery box and a battery module arranged in the battery box, wherein the battery box is sealed relative to the outside, sealing liquid is arranged in the battery box, the battery module is at least partially immersed in the sealing liquid, a water-absorbing polymer A is added in the sealing liquid, and the liquid absorption rate of the water-absorbing polymer A is more than 10%. The technical scheme provided by the invention can effectively inhibit the spread of thermal runaway of the battery pack.
Description
Technical Field
A battery pack including a thermal control system is disclosed.
Background
The power system of the energy storage/electric automobile is composed of a plurality of battery modules, and each battery module is composed of a plurality of battery monomers. Due to the pursuit of energy density of the battery pack, the arrangement of the battery cells in the battery module is so tight that heat is easily accumulated in the battery module, and particularly, the temperature of the middle part of the whole module is often higher than that of other parts. When the heat of a part of the battery cells in the module is accumulated to a certain degree, a thermal runaway phenomenon may occur. Furthermore, thermal runaway can propagate within the battery module, causing other cells operating properly to rapidly increase in temperature, thereby causing thermal runaway throughout the battery module, which is extremely dangerous, particularly within a closed battery box.
Patent application No. CN201280043177.9 entitled "fire extinguishing device for battery pack" discloses a device capable of suppressing the occurrence of fire in the battery pack when the battery pack catches fire. The fire extinguishing apparatus includes: a fire detection sensor for detecting whether the battery pack is on fire or not; a fire extinguishing agent container containing a fire extinguishing agent in an inner space thereof; and a control unit for injecting the fire extinguishing agent in the fire extinguishing agent container into the interior of the battery pack when the occurrence of a fire is detected by the fire detection sensor.
The fire detection sensor in this patent is used to detect whether the battery pack is on fire or not, and it is proved that the fire extinguishing apparatus starts to operate only when an open fire occurs in the battery pack. In fact, the battery pack exhibits the form of smoke in the early stage of thermal runaway, and the temperature of the battery cells showing obvious symptoms rises rapidly and suddenly, and once a certain battery cell begins to undergo thermal runaway, heat energy is continuously generated and adjacent battery cells may be heated to a temperature higher than the critical temperature of the thermal runaway, so that the healthy battery cells enter the thermal runaway. This phenomenon rapidly spreads to generate heat continuously until other adjacent battery cells are heated to a thermal runaway state.
The application number is CN201410186474.X, discloses in the patent application of the name "a high waterproof heat preservation battery box of electric automobile", a battery box, and it includes a plurality of battery unit in sealed box and the box, still including setting up in the box and the heat abstractor who links to each other with a plurality of battery unit. Every battery unit sets up heating device, the box in still set up the battery box controller that links to each other through control circuit and heating device, still designed the cavity heating panel and dispel the heat for every battery unit module, guarantee that the battery unit module heat dissipation is even, improve the radiating efficiency. The technical scheme who discloses in this patent can solve the free temperature homogeneity problem of battery of group battery when normal operating condition, but because the heating panel has played the heat conduction effect, in case certain battery monomer takes place the thermal runaway, the heat can conduct to other normal battery monomer rapidly, leads to the thermal runaway to spread rapidly.
In the prior art, in order to better control the temperature of the battery pack, a cooling loop is arranged between battery monomers, so that the temperature difference of each battery monomer in the battery module is reduced, and a communicated fire extinguishing device is arranged outside a battery box. The arrangement of fire extinguishing devices or similar devices in the battery pack system is only a remedy after the thermal runaway of the battery pack occurs and cannot effectively control the thermal runaway in the bud. The cooling device is designed in the battery pack system, generally, air cooling and liquid cooling are adopted, the air volume is relatively poor, the liquid cooling is used for achieving a good heat dissipation effect, the battery module is required to be immersed into the cooling liquid, the liquid with good insulation performance is generally selected for the safety performance of the battery pack, the insulation cooling liquid is low in heat capacity value and high in boiling point, phase change is difficult to occur under the thermal runaway temperature of the battery pack, and the generated heat is difficult to take away quickly when the temperature rises sharply. More disadvantageously, if the temperature of the insulating cooling liquid rises rapidly, an oil bath effect is also achieved, and other batteries which normally work are also heated to a thermal runaway state, so that more serious consequences are brought.
Taking positive remedial measures after thermal runaway of the battery pack is a method for controlling thermal runaway. Although the remedial measures can have a certain effect and do not bring serious danger, the battery pack after thermal runaway cannot work normally, and serious loss is brought. If thermal runaway can be suppressed in the germinating state during the early temperature rise, not only is the occurrence of danger controlled, but also unnecessary losses are greatly reduced.
Disclosure of Invention
The invention provides a battery pack comprising a thermal control system, which comprises a battery box and a battery module arranged in the battery box, wherein the battery box is sealed relative to the outside, sealing liquid is arranged in the battery box, the battery module is at least partially immersed in the sealing liquid, a water-absorbing polymer A is added in the sealing liquid, and the liquid absorption rate of the water-absorbing polymer A is more than 10%.
The sealing liquid seals all the electrical components of the battery pack to isolate the electrical components from the outside, so that the damage of air to the electrical components is avoided. Under this prerequisite, if the group battery leaks, the liquid that leaks flows into in the confining liquid, is sealed by the confining liquid, avoids air and its contact to react.
Further, the liquid absorption rate of the water-absorbent polymer a is 50% or more, and more preferably 100% or more.
Preferably, the confining liquid is further added with a water-absorbing polymer B, and the liquid absorption rate of the water-absorbing polymer B is less than 50%; preferably, the liquid absorption rate of the water-absorbent polymer B is less than 20%; more preferably, the water-absorbent polymer B has a liquid absorption rate of 0.
The addition amount of the water-absorbing polymer A and the water-absorbing polymer B in the confining liquid meets the requirement that the mass ratio of the pure water-absorbing polymer A to the pure water-absorbing polymer B is 5-200: 1, and more preferably the mass ratio of the pure water-absorbing polymer A to the pure water-absorbing polymer B is 10-100: 1; the mass of the pure water-absorbent polymer a or the pure water-absorbent polymer B means the mass of the water-absorbent polymer a or the water-absorbent polymer B that does not absorb any liquid, that is, the mass of the pure polymer.
In the present invention, the liquid absorption rate is the mass percentage of the liquid absorbed by the water-absorbent polymer to the water-absorbent polymer before the liquid is not absorbed, i.e., the liquid absorption rate is W1(liquid mass)/W2(mass of water-absorbent Polymer before Water absorption) × 100%. wherein W is1(mass of liquid) W3(quality of Water-absorbent Polymer after Water absorption) -W2(quality of water-absorbent polymer before water absorption).
According to one embodiment of the invention, the confining liquid comprises an insulating flame retardant liquid having a freezing point below-30 ℃ and a decomposition temperature above 60 ℃. According to another embodiment of the present invention, the confining liquid comprises an insulating flame retardant liquid having a freezing point below-30 ℃ and a boiling point above 60 ℃.
The sealing liquid is a cooling liquid with insulating and flame-retardant properties, and has a freezing point lower than-30 ℃ and a boiling point or decomposition temperature higher than 60 ℃. Generally, the normal operating temperature of the battery pack is not higher than 60 ℃, so the decomposition temperature of the sealing liquid should be higher than 60 ℃. The insulating flame-retardant liquid may be at least one selected from the group consisting of silicone oil, transformer oil, chlorofluorocarbons, hydrofluorocarbons, chlorohydrocarbons, and hydrofluoroethers.
The silicone oil, the transformer oil and the like have good insulating property and high stability. The battery module and the electrical component are immersed in the sealing liquid, so that the damage of external moisture can be avoided, and the service life is prolonged; but also has the function of heat conduction, and is favorable for the uniform temperature inside the battery pack.
The water-absorbent polymer A and/or the water-absorbent polymer B in the present invention are generally polymers having a hydrophilic group, which can absorb a large amount of water while swelling and can retain water without outflow. It is understood that any polymer which can absorb water or an aqueous solution and is insoluble or slightly soluble in a closed solution can be used as the water-absorbent polymer of the present invention to achieve the technical effects of the present invention. According to an embodiment of the present invention, the water-absorbent polymer a and/or the water-absorbent polymer B may be at least one independently selected from the group consisting of acrylic polymers, acrylamide polymers, starch polymers, acrylonitrile polymers, cellulose polymers, vinyl alcohol polymers, and polyoxyethylene polymers.
Preferably, the water-absorbent polymer a and/or the water-absorbent polymer B may be independently selected from: crosslinked polyacrylates, polyacrylate graft polymers, saponified vinyl acetate-acrylate copolymers, vinyl alcohol-acrylate crosslinked copolymers, hydrolyzed acrylamide copolymers, grafted acrylamide polymers, crosslinked hydroxyethylcellulose graft acrylamide polymers, starch-acrylic acid graft copolymers, starch graft acrylate polymers, starch-acrylonitrile graft copolymers, hydrolyzed acrylonitrile copolymers, highly substituted crosslinked carboxymethylcellulose, crosslinked carboxymethylcellulose-grafted acrylamide, crosslinked alkali metal carboxymethylcellulose, crosslinked polymers of polyvinyl alcohol grafted with maleic anhydride, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, poly (vinylsulfonates), poly (vinylphosphonates), poly (acrylamides), poly (hydroxyethylcellulose) acrylates, poly (methacrylamides), poly, At least one of poly (vinyl phosphate), poly (vinyl sulfate), sulfonated polystyrene, polyvinylamine, polydialkylamino alkyl (meth) acrylamide, polyethyleneimine, polyarylamine, polyarylguanidine, polydimethyldiarylammonium hydroxide, quaternized polystyrene derivatives, guanidine-modified polystyrene, quaternized poly (meth) acrylamide, polyvinylguanidine, and the like. For the purposes of the present invention, the water-absorbing polymer A and the water-absorbing polymer B may be the same or different.
The water-absorbent polymer is generally a polyelectrolyte containing a hydrophilic group and a crosslinked structure. Before water absorption, the polymer chains are mutually close and twined together and are mutually crosslinked into a net structure, so that the integral fastening is realized. When contacting water, water molecules penetrate into the resin through capillary action and diffusion action, and the ionized groups on the chains are ionized in the water. The polymer chains are stretched and swollen due to electrostatic repulsion between the same ions on the chains. Due to the requirement of electric neutrality, counter ions cannot migrate to the outside of the resin, and the ion concentration difference between the solution inside and outside the resin forms reverse osmosis pressure. The water further enters the resin under the action of reverse osmosis pressure to form hydrogel.
The water-absorbing polymer can absorb water which is several hundred times to several thousand times of the self weight, and has high water absorption rate and difficult release after water absorption. The liquid that can be absorbed by the water-absorbent resin is not limited to water, and has strong absorption capacity for other types of liquid.
According to one embodiment of the present invention, the liquid absorbed in the water-absorbent polymer a and/or the water-absorbent polymer B is at least one selected from water and aqueous solutions. The aqueous solution is preferably a solution obtained by dissolving other substances having a high specific heat capacity in water.
The water and the aqueous solution obtained by dissolving other substances with high specific heat capacity in the water have higher specific heat capacity, and the boiling point of the water or the aqueous solution is below the temperature of thermal runaway of the battery pack, so that the phase change of the water or the aqueous solution can be generated before the thermal runaway further spreads, more heat can be absorbed, and the large-range spread of the thermal runaway in the battery pack can be effectively controlled.
According to one embodiment of the present invention, the liquid absorbed in the water-absorbent polymer a and/or the water-absorbent polymer B is water or an aqueous solution; the aqueous solution is selected from aqueous alcohol solutions; the alcohol may be at least one selected from ethylene glycol, 1, 2-ethylene glycol, propylene glycol, 1, 3-butylene glycol, hexylene glycol, diethylene glycol, glycerin, and the like. The aqueous solution of the substances can effectively reduce the freezing point and improve the working performance in a low-temperature environment.
And adding the water-absorbing polymer A and/or the water-absorbing polymer B into the confining liquid, wherein the water-absorbing polymer A and the water-absorbing polymer B are insoluble or slightly soluble in the confining liquid and keep stable. The liquid absorption rate of the water-absorbent polymer a is 10% or more, preferably 50% or more, and more preferably 100% or more. When the local heat of the battery module is accumulated, the temperature is rapidly increased and local thermal runaway occurs, the sealing liquid is not enough to take away the rapidly generated heat, the liquid (such as water or aqueous solution) in the water-absorbing polymer A can be rapidly heated and then phase change is carried out to absorb a large amount of heat, the temperature in the battery pack is controlled, and the further spread of the thermal runaway is avoided.
The sealing liquid may contain a certain amount of moisture after a long-term use, which may degrade the insulation performance of the entire battery pack. The water-absorbing polymer B with the liquid absorption rate of below 20% is arranged in the sealing liquid, so that the sealing liquid is favorably dewatered, and the battery pack keeps better insulating property.
According to the object of the present invention, when the water-absorbent polymer a (and the water-absorbent polymer B) is added to the sealing liquid, the amount of the water-absorbent polymer a should be larger than that of the water-absorbent polymer B in order to secure the temperature control effect in the battery pack.
According to one embodiment of the present invention, the water-absorbent polymer a and/or the water-absorbent polymer B is separated from the battery module by a porous layer which does not allow the water-absorbent polymer a and/or the water-absorbent polymer B to directly contact the battery module, and the liquid absorbed in the water-absorbent polymer a and/or the water-absorbent polymer B and the blocking liquid can freely pass through the porous layer.
The porous layer is at least one selected from the group consisting of a nonwoven fabric, a porous film, a web, and the like. In a specific operation, the water-absorbent polymer a and/or the water-absorbent polymer B may be wrapped in a porous layer such as a nonwoven fabric, and then placed in a sealing liquid in a battery case.
Preferably, the battery module is placed upside down in a battery case such that the tabs of the battery module are immersed in a sealing liquid.
The battery unit is placed upside down, namely the battery unit electrode lug faces downwards, so that the electrode can be immersed into the sealing liquid when less sealing liquid is used. The heat productivity of the electrode lug is relatively large for the battery monomer, and the electrode lug is immersed in the sealing liquid to be more favorable for heat dissipation and also favorable for insulation of the battery module.
For a flexible package battery, the packaging position of the tab is a position where a breach is relatively easy to occur, active substances in the battery easily flow out from the breach, the inversion of a battery monomer is beneficial to reducing the time of exposing leaked substances in air, and once leakage occurs, the leaked substances quickly flow into sealing liquid, so that the safety performance is improved.
The technical scheme disclosed by the invention can more effectively control the spread of thermal runaway of the battery module. When some cells in the battery module have problems, the generated large amount of heat enables the local temperature to rise rapidly, at the moment, liquid absorbed in the water-absorbing polymer A and/or the water-absorbing polymer B can absorb a large amount of heat, and the heat is taken away by utilizing the phase change of the liquid, so that the rapid rise of the temperature in the battery module is effectively controlled, the temperature in the battery pack is effectively controlled, the thermal runaway is prevented from spreading, and the loss is reduced to the lowest.
Drawings
FIG. 1 is a schematic structural diagram of one embodiment of a battery pack of the present disclosure;
FIG. 2 is a schematic structural view of a water-absorbent polymer A coated in a porous layer according to the present disclosure;
FIG. 3 is a schematic structural view of a water-absorbent polymer B coated in a porous layer according to the present invention;
FIG. 4 is a schematic structural view of another embodiment of the battery pack of the present disclosure;
fig. 5 is a schematic structural view of another embodiment of the battery pack disclosed in the present invention;
FIG. 6 is a schematic structural view of a water-absorbent polymer A and a water-absorbent polymer B contained in a porous layer according to the present disclosure;
the battery module comprises a battery box 1, a porous layer 11, water-absorbing polymers A and B12, a sealing liquid 13, and a battery module 2.
Detailed Description
Example 1
As shown in fig. 1, 2 and 3, the present invention discloses a battery pack comprising a battery case 1 and a battery module 2, wherein the battery case 1 is sealed from the outside, a sealing liquid 14 is further provided in the battery case 1, the battery module 2 is disposed in the battery case 1 upside down such that tabs of the battery module 2 are immersed in the sealing liquid 14, electrical components in the battery module 2 and the battery case 1 are immersed in the sealing liquid 14, particularly tab portions and current collecting portions in the battery module 2, a porous layer 11, a water-absorbing polymer a12 and a water-absorbing polymer B13 are further provided in the sealing liquid 14, the water-absorbing polymer a12 and the water-absorbing polymer B13 are insoluble in the sealing liquid 14, the liquid absorption rate of the water-absorbing polymer a12 is 20% or more, and the liquid absorption rate of the water-absorbing polymer B13 is 20% or less.
The water-absorbing polymer A12 is arranged in the porous layer 11, the water-absorbing polymer B13 is arranged in the other porous layer 11 which does not contain the water-absorbing polymer A12, the porous layer 11 enables the confining liquid 14 to pass through and flow into the porous layer 11, the water-absorbing polymer A12 and the water-absorbing polymer B13 cannot pass through, the positions of the water-absorbing polymer A12 and the water-absorbing polymer B13 are limited, the water-absorbing polymer A12 and the water-absorbing polymer B13 are not in direct contact with charged parts/electric parts of the battery cells, and the porous layer 11 is made of non-woven fabrics.
After the sealing liquid 14 is used for a long time, a certain amount of moisture may be absorbed, which may reduce the insulation performance of the whole battery pack, and the water-absorbing polymer B13 with the liquid absorption rate of less than 20% is arranged in the sealing liquid 14, which is beneficial to removing moisture from the sealing liquid 14 and maintaining good insulation performance. When the thermal runaway occurs locally in the battery module 2, the moisture in the water-absorbent polymer a12 and the water-absorbent polymer B13 is changed into water vapor, so that heat is absorbed quickly, and the thermal runaway is prevented from spreading.
In addition, in this example, the mass ratio of the pure water-absorbent polymer a12 to the pure water-absorbent polymer B13 was 8.
The liquid in the water-absorbing polymer A12 and the water-absorbing polymer B13 is ethylene glycol aqueous solution, the water-absorbing polymer A12 and the water-absorbing polymer B13 are cross-linked polyacrylate, and silicone oil is adopted as the sealing liquid 14.
Example 2
As shown in fig. 1, 2 and 3, the present invention discloses a battery pack comprising a battery case 1 and a battery module 2, wherein the battery case 1 is sealed from the outside, a sealing liquid 14 is further provided in the battery case 1, the battery module 2 is disposed in the battery case 1 upside down such that tabs of the battery module 2 are immersed in the sealing liquid 14, the battery module 2 and electrical components in the battery case 1 are immersed in the sealing liquid 14, particularly tab portions and current collecting portions in the battery module 2, a porous layer 11, a water-absorbing polymer a12 and a water-absorbing polymer B13 are further provided in the sealing liquid 14, the water-absorbing polymer a12 and the water-absorbing polymer B13 are insoluble in the sealing liquid 14, the liquid absorption rate of the water-absorbing polymer a12 is 50% or more, and the liquid absorption rate of the water-absorbing polymer B13 is 20% or less.
The water-absorbing polymer A12 is arranged in the porous layer 11, the water-absorbing polymer B13 is arranged in the other porous layer 11 which does not contain the water-absorbing polymer A12, the porous layer 11 enables the confining liquid 14 to pass through and flow into the porous layer 11, the water-absorbing polymer A12 and the water-absorbing polymer B13 cannot pass through, the positions of the water-absorbing polymer A12 and the water-absorbing polymer B13 are limited, the water-absorbing polymer A12 and the water-absorbing polymer B13 are not in direct contact with charged parts/electric parts of the battery cells, and the porous layer 11 is made of non-woven fabrics.
After the sealing liquid 14 is used for a long time, a certain amount of moisture may be absorbed, which may reduce the insulation performance of the whole battery pack, and the water-absorbing polymer B13 with the liquid absorption rate of less than 20% is arranged in the sealing liquid 14, which is beneficial to removing moisture from the sealing liquid 14 and maintaining good insulation performance. When thermal runaway occurs locally in the battery module 2, the water phases in the water-absorbent polymer a12 and the water-absorbent polymer B13 are changed into water vapor, so that heat is absorbed quickly, and the thermal runaway is prevented from spreading.
In addition, in this example, the mass ratio of the pure water-absorbent polymer a12 to the pure water-absorbent polymer B13 was 20.
The liquid in the water-absorbing polymer A12 and the water-absorbing polymer B13 is 1, 2-ethylene glycol aqueous solution, the water-absorbing polymer A12 and the water-absorbing polymer B13 are vinyl alcohol-acrylate cross-linked copolymers, and silicone oil is adopted as the sealing liquid 14.
Example 3
As shown in fig. 1, 2 and 3, the present invention discloses a battery pack comprising a battery case 1 and a battery module 2, wherein the battery case 1 is sealed from the outside, a sealing liquid 14 is further provided in the battery case 1, the battery module 2 is disposed in the battery case 1 upside down such that tabs of the battery module 2 are immersed in the sealing liquid 14, electrical components in the battery module 2 and the battery case 1 are immersed in the sealing liquid 14, particularly tab portions and current collecting portions in the battery module 2, a porous layer 11, a water-absorbing polymer a12 and a water-absorbing polymer B13 are further provided in the sealing liquid 14, the water-absorbing polymer a12 and the water-absorbing polymer B13 are insoluble in the sealing liquid 14, the liquid absorption rate of the water-absorbing polymer a12 is 80% or more, and the liquid absorption rate of the water-absorbing polymer B13 is 10% or less.
The water-absorbing polymer A12 is arranged in the porous layer 11, the water-absorbing polymer B13 is arranged in the other porous layer 11 which does not contain the water-absorbing polymer A12, the porous layer 11 enables the confining liquid 14 to pass through and flow into the porous layer 11, the water-absorbing polymer A12 and the water-absorbing polymer B13 cannot pass through, the positions of the water-absorbing polymer A12 and the water-absorbing polymer B13 are limited, the water-absorbing polymer A12 and the water-absorbing polymer B13 are not in direct contact with charged parts/electric parts of the battery cells, and the porous layer 11 is made of non-woven fabrics.
After the sealing liquid 14 is used for a long time, a certain amount of moisture may be absorbed, which may reduce the insulation performance of the whole battery pack, and the water-absorbing polymer B13 with the liquid absorption rate of less than 10% is arranged in the sealing liquid 14, which is beneficial to removing moisture from the sealing liquid 14 and maintaining good insulation performance. When thermal runaway occurs locally in the battery module 2, the water phases in the water-absorbent polymer a12 and the water-absorbent polymer B13 are changed into water vapor, so that heat is absorbed quickly, and the thermal runaway is prevented from spreading.
In addition, in this example, the mass ratio of the pure water-absorbent polymer a12 to the pure water-absorbent polymer B13 was 10.
The liquid in the water-absorbing polymer A12 and the water-absorbing polymer B13 is water, the water-absorbing polymer A12 and the water-absorbing polymer B13 are vinyl alcohol-acrylate cross-linked copolymers, and silicone oil is adopted as the confining liquid 14.
Example 4
As shown in fig. 4, the present invention discloses a battery pack, which comprises a battery box 1 and a battery module 2, wherein the battery box 1 is sealed from the outside, a sealing liquid 14 is further provided in the battery box 1, the battery module 2 is arranged in the battery box 1 upside down, so that tabs of the battery module 2 are immersed in the sealing liquid 14, electrical components in the battery module 2 and the battery box 1 are immersed in the sealing liquid 14, particularly tab positions and current collecting positions in the battery module 2, a water-absorbing polymer a12 and a water-absorbing polymer B13 are further provided in the sealing liquid 14, the water-absorbing polymer a12 and the water-absorbing polymer B13 are insoluble in the sealing liquid 14, the liquid absorption rate of the water-absorbing polymer a12 is above 80%, and the liquid absorption rate of the water-absorbing polymer B13 is below 10%.
After the sealing liquid 14 is used for a long time, a certain amount of moisture may be absorbed, which may reduce the insulation performance of the whole battery pack, and the water-absorbing polymer B13 with the liquid absorption rate of less than 10% is arranged in the sealing liquid 14, which is beneficial to removing moisture from the sealing liquid 14 and maintaining good insulation performance. When thermal runaway occurs locally in the battery module 2, the water phases in the water-absorbent polymer a12 and the water-absorbent polymer B13 are changed into water vapor, so that heat is absorbed quickly, and the thermal runaway is prevented from spreading.
In addition, in this example, the mass ratio of the pure water-absorbent polymer a12 to the pure water-absorbent polymer B13 was 10.
The liquid in the water-absorbing polymer A12 and the water-absorbing polymer B13 is propylene glycol aqueous solution, the water-absorbing polymer A12 and the water-absorbing polymer B13 are vinyl alcohol-acrylate cross-linked copolymer, and silicone oil is adopted as the confining liquid 14.
Example 5
As shown in fig. 5, the present invention discloses a battery pack, which comprises a battery box 1 and a battery module 2, wherein the battery box 1 is sealed from the outside, a sealing liquid 14 is further arranged in the battery box 1, the battery module 2 is arranged in the battery box 1 in an inverted manner, so that tabs of the battery module 2 are immersed in the sealing liquid 14, electrical components in the battery module 2 and the battery box 1 are immersed in the sealing liquid 14, particularly tab positions and current collecting positions in the battery module 2, a water-absorbing polymer a12 is further arranged in the sealing liquid 14, the water-absorbing polymer a12 is insoluble in the sealing liquid 14, and the liquid absorption rate of the water-absorbing polymer a12 is more than 80%.
When thermal runaway locally occurs in the battery module 2, the water phase in the water-absorbent polymer a12 is changed into water vapor, so that heat is quickly absorbed, and the spread of the thermal runaway is avoided.
The liquid in the water-absorbing polymer A12 is propylene glycol aqueous solution, the water-absorbing polymer A12 is vinyl alcohol-acrylate cross-linked copolymer, and silicone oil is adopted as the confining liquid 14.
Example 6
As shown in fig. 1 and 6, the present invention discloses a battery pack comprising a battery case 1 and a battery module 2, wherein the battery case 1 is sealed from the outside, a sealing liquid 14 is further provided in the battery case 1, the battery module 2 is disposed in the battery case 1 upside down such that tabs of the battery module 2 are immersed in the sealing liquid 14, the battery module 2 and electrical components in the battery case 1 are immersed in the sealing liquid 14, particularly tab portions and current collecting portions in the battery module 2, a porous layer 11, a water-absorbent polymer a12 and a water-absorbent polymer B13 are further provided in the sealing liquid 14, the water-absorbent polymer a12 and the water-absorbent polymer B13 are insoluble in the sealing liquid 14, the liquid absorption rate of the water-absorbent polymer a12 is 20% or more, and the liquid absorption rate of the water-absorbent polymer B13 is 20% or less.
The water-absorbing polymer A12 and the water-absorbing polymer B13 are arranged in the same porous layer, the porous layer 11 enables the confining liquid 14 to pass through and flow into the porous layer 11, the water-absorbing polymer A12 and the water-absorbing polymer B13 cannot pass through, the positions of the water-absorbing polymer A12 and the water-absorbing polymer B13 are limited, the water-absorbing polymer A12 and the water-absorbing polymer B13 are not in direct contact with a charged part/electric part of a battery cell, and the porous layer 11 is made of non-woven fabrics.
After the sealing liquid 14 is used for a long time, a certain amount of moisture may be absorbed, which may reduce the insulation performance of the whole battery pack, and the water-absorbing polymer B13 with the liquid absorption rate of less than 20% is arranged in the sealing liquid 14, which is beneficial to removing moisture from the sealing liquid 14 and maintaining good insulation performance. When the thermal runaway occurs locally in the battery module 2, the moisture in the water-absorbent polymer a12 and the water-absorbent polymer B13 is changed into water vapor, so that heat is absorbed quickly, and the thermal runaway is prevented from spreading.
In addition, in this example, the mass ratio of the pure water-absorbent polymer a12 to the pure water-absorbent polymer B13 was 8.
The liquid in the water-absorbing polymer A12 and the water-absorbing polymer B13 is ethylene glycol aqueous solution, the water-absorbing polymer A12 and the water-absorbing polymer B13 are cross-linked polyacrylate, and silicone oil is adopted as the sealing liquid 14.
Claims (15)
1. A battery pack including a battery case and a battery module provided in the battery case, the battery case being sealed with respect to the outside, characterized in that: the battery box is internally provided with sealing liquid, the battery module is at least partially immersed in the sealing liquid, a water-absorbing polymer A is added into the sealing liquid, the liquid absorption rate of the water-absorbing polymer A is more than 10%, a water-absorbing polymer B is further added into the sealing liquid, and the liquid absorption rate of the water-absorbing polymer B is less than 50%.
2. The battery pack according to claim 1, characterized in that: the liquid absorption rate of the water-absorbing polymer A is more than 50%.
3. The battery pack according to claim 1, characterized in that: the liquid absorption rate in the water-absorbent polymer B is less than 20%.
4. The battery pack according to claim 3, characterized in that: the addition amount of the water-absorbing polymer A and the water-absorbing polymer B in the confining liquid meets the requirement that the mass ratio of the pure water-absorbing polymer A to the pure water-absorbing polymer B is 5-200: 1.
5. The battery pack according to claim 1, characterized in that: the sealing liquid contains insulating flame-retardant liquid with freezing point lower than-30 ℃ and decomposition temperature higher than 60 ℃.
6. The battery pack according to claim 5, characterized in that: the insulating flame-retardant liquid is selected from at least one of silicone oil, transformer oil, chlorofluorocarbon, hydrofluorocarbon, chlorohydrocarbon and hydrofluoroether.
7. The battery pack according to any one of claims 1 to 6, wherein: the water-absorbing polymer A and/or the water-absorbing polymer B is at least one selected from acrylic polymers, acrylamide polymers, starch polymers, acrylonitrile polymers, cellulose polymers, vinyl alcohol polymers and polyoxyethylene polymers.
8. The battery pack according to any one of claims 1 to 6, wherein: the water-absorbing polymer A and/or the water-absorbing polymer B is selected from crosslinked polyacrylate, polyacrylate graft polymer, saponified vinyl acetate-acrylate copolymer, vinyl alcohol-acrylate crosslinked copolymer, hydrolyzed acrylamide copolymer, grafted acrylamide polymer, crosslinked hydroxyethyl cellulose grafted acrylamide polymer, starch-acrylic acid graft copolymer, starch-acrylic acid graft acrylate polymer, starch-acrylonitrile graft copolymer, hydrolyzed acrylonitrile copolymer, high-substitution crosslinked carboxymethyl cellulose, crosslinked carboxymethyl cellulose grafted acrylamide, crosslinked carboxymethyl cellulose alkali metal salt, crosslinked polymer of polyvinyl alcohol grafted with maleic anhydride, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, crosslinked acrylic acid ester, crosslinked acrylic acid amide, crosslinked hydroxyethyl cellulose grafted acrylamide polymer, starch-acrylic acid graft copolymer, starch-acrylic acid graft acrylate polymer, starch-acrylonitrile graft copolymer, hydrolyzed acrylonitrile copolymer, high-substitution crosslinked carboxymethyl, At least one of poly (vinyl sulfonate), poly (vinyl phosphonate), poly (vinyl phosphate), poly (vinyl sulfate), sulfonated polystyrene, polyvinylamine, polydialkylamino alkyl methacrylamide, polyethyleneimine, polyarylamine, polyarylguanidine, polydimethyldiarylammonium hydroxide, quaternized polystyrene derivatives, guanidine-modified polystyrene, quaternized polymethacrylamide, polyvinylguanidine.
9. The battery pack according to any one of claims 1 to 6, wherein: the liquid absorbed in the water-absorbent polymer A and/or the water-absorbent polymer B is at least one selected from the group consisting of water and aqueous solutions.
10. The battery pack of claim 9, wherein: the aqueous solution is selected from aqueous alcohol solutions.
11. The battery pack of claim 10, wherein: the alcohol is at least one selected from ethylene glycol, 1, 2-ethylene glycol, propylene glycol, 1, 3-butylene glycol, hexylene glycol, diethylene glycol and glycerol.
12. The battery pack according to any one of claims 1 to 6, wherein: the water-absorbing polymer A and/or the water-absorbing polymer B are separated from the battery module by a porous layer which prevents the water-absorbing polymer A and/or the water-absorbing polymer B from being in direct contact with the battery module, and the liquid absorbed in the water-absorbing polymer A and/or the water-absorbing polymer B and the confining liquid can freely pass through the porous layer.
13. The battery pack of claim 12, wherein: the porous layer is at least one selected from the group consisting of a nonwoven fabric, a porous film and a web.
14. The battery pack according to claim 1, characterized in that: the battery module is placed in an inverted manner in the battery box, so that the tabs of the battery module are immersed in the sealing liquid.
15. The battery pack according to claim 2, characterized in that: the liquid absorption rate of the water-absorbing polymer A is more than 100%.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2015/083135 WO2017000293A1 (en) | 2015-07-02 | 2015-07-02 | Battery pack |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107615568A CN107615568A (en) | 2018-01-19 |
| CN107615568B true CN107615568B (en) | 2020-09-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201580079443.7A Active CN107615568B (en) | 2015-07-02 | 2015-07-02 | Battery pack |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN107615568B (en) |
| WO (1) | WO2017000293A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102020007367A1 (en) | 2020-12-03 | 2022-06-09 | Mercedes-Benz Group AG | Device for immersion cooling of at least one cell module |
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2015
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| Publication number | Publication date |
|---|---|
| WO2017000293A1 (en) | 2017-01-05 |
| CN107615568A (en) | 2018-01-19 |
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Effective date of registration: 20230803 Address after: 12603 Southwest Avenue, 300 blocks, Stanford, Texas, United States Patentee after: MICROVAST, Inc. Address before: 313000 No. 2198 Hongfeng Road, Huzhou Economic and Technological Development Zone, Zhejiang Province Patentee before: MICROVAST POWER SYSTEMS Co.,Ltd. |