Disclosure of Invention
In view of the above, the present invention provides a battery heat dissipation method, a battery heat dissipation device suitable for the battery heat dissipation method, and a battery pack, wherein the battery pack is provided with a liquid cooling system and an air cooling system, so that the battery pack can achieve both cooling effect and energy saving effect.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for dissipating heat from a battery, comprising:
step S1: measuring to obtain a temperature parameter T of a preset position of the battery pack;
step S2: calculating a first derivative of the temperature parameter T and time to obtain a first parameter T', and calculating a second derivative of the temperature parameter T and time to obtain a second parameter T ";
step S3: judging whether the second parameter T' is greater than a first preset value a, if so, performing step S4, otherwise, performing step S5;
step S4: judging whether the temperature parameter T is greater than a second preset value T1, if so, starting the liquid cooling system, and otherwise, performing the step S5;
step S5: judging whether the first parameter T' is larger than a third preset value b, if so, performing step S6, otherwise, performing step S7;
step S6: judging whether the temperature parameter T is greater than a fourth preset value T2, wherein the fourth preset value T2 is greater than the second preset value T1, if so, starting the liquid cooling system, and otherwise, starting the air cooling system;
step S7: and judging whether the temperature parameter T is greater than a fifth preset value T3, wherein the fifth preset value T3 is greater than the fourth preset value T2, if so, starting the air cooling system, and if not, returning to the step S3.
Optionally, in the above battery heat dissipation method, the first preset value a is equal to zero; the third preset value b is equal to zero.
Optionally, in the above battery heat dissipation method, the temperature parameter T is an average temperature value of a plurality of measurement positions in the battery pack.
Optionally, in the above battery heat dissipation method, the measurement positions include a positive end measurement position, a middle measurement position, and a negative end measurement position of each battery module in the battery pack.
A battery heat sink, the battery heat sink comprising:
the measuring unit is used for measuring the temperature parameter T of the preset position of the battery pack;
the liquid cooling system is used for cooling the battery pack;
the air cooling system is used for cooling the battery pack;
a control unit for performing the steps S2 to S6 described hereinabove.
A battery pack comprises a lower shell and an upper cover, wherein the upper cover and the lower shell are buckled to form a cavity for accommodating a battery module; and the bottom of the lower shell is provided with an air circulation path in an air cooling system and a cooling liquid circulation path in a liquid cooling system.
Optionally, in the battery pack, the air circulation path is a through groove structure formed by recessing a bottom plate of the lower case, and the battery modules are respectively arranged on two sides of the air circulation path in the lower case;
and/or the cooling liquid circulation path is a flat through hole structure arranged in the bottom plate of the lower shell and is positioned right below the battery module.
Optionally, in the above battery pack, a fan is disposed outside the lower case, and an outlet of the fan is located at one end of the air circulation path and is communicated with the air circulation path.
Optionally, in the above battery pack, a gap between the inner surface of the lower case and the battery module is filled with a thermally conductive adhesive.
Optionally, in the above battery pack, the upper cover is made of a polymer composite material;
the lower shell is made of aluminum alloy.
According to the technical scheme, the battery heat dissipation method, the battery heat dissipation device and the battery pack have the functions of forced air cooling and liquid cooling heat dissipation, so that two cooling modes can be switched as required, the working efficiency of a battery pack cooling system is improved, and the energy consumption is reduced.
Detailed Description
The invention discloses a battery heat dissipation method, a battery heat dissipation device suitable for the battery heat dissipation method and a battery pack.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The battery heat dissipation method provided by the embodiment of the invention comprises the following steps:
after the battery system is started, whether T 'is larger than zero is detected, and if not, whether T' is larger than zero is further judged. If T' is larger than zero, the temperature of the battery is increased in an accelerating way, and if T at the moment exceeds a threshold value T1, the liquid cooling function needs to be started immediately to rapidly cool the battery. If T does not reach the threshold T1, it indicates that the battery temperature is still within a reasonable range, and then it is determined whether T' is greater than zero. If T' is not greater than zero, it indicates that the battery temperature is dropping or temporarily remaining unchanged, and it is necessary to determine whether T is greater than a threshold T3. If T' is larger than zero, the temperature of the battery is marked to be rising, and if T at the moment exceeds a threshold value T2, the liquid cooling function needs to be started to cool the battery. Otherwise, only the forced air cooling is started. If T "is not greater than zero, T' is also not greater than zero, but T is greater than a threshold T3, it indicates that the battery temperature is high, but there is no significant increase, and only the forced air cooling needs to be turned on for cooling. Typically, we set T1 < T2 < T3.
Specifically, referring to fig. 1, the control logic of the battery heat dissipation method mainly includes the following steps:
step S1: after the battery system is started, firstly, a temperature parameter T of a preset position of the battery pack is measured, and the temperature parameter T is preferably an average temperature value of a plurality of measurement positions in the battery pack (but not limited to this, in other specific embodiments, a maximum temperature value or a minimum temperature value of the battery pack obtained by measurement or a temperature value of a certain specific position may also be used as the temperature parameter T);
step S2: calculating a first derivative of the temperature parameter T and time to obtain a first parameter T' (namely dT/dT); calculating a second derivative of the temperature parameter T and time to obtain a second parameter T '(namely dT'/dT);
step S3: determining whether the second parameter T ″ is greater than the first preset value a (the first preset value a is preferably zero, but is not limited thereto, and in specific implementation, the first preset value a may also be set as another parameter), if so, performing step S4, otherwise, performing step S5;
step S4: judging whether the temperature parameter T is greater than a second preset value T1, if so, starting the liquid cooling system, and otherwise, performing the step S5;
step S5: judging whether the first parameter T' is greater than a third preset value b (the third preset value b is preferably zero, but is not limited thereto, and in specific implementation, the third preset value b may also be set to other parameters), if so, performing step S6, otherwise, performing step S7;
step S6: judging whether the temperature parameter T is greater than a fourth preset value T2, and whether the fourth preset value T2 is greater than a second preset value T1, if so, starting the liquid cooling system, and otherwise, starting the air cooling system;
step S7: and judging whether the temperature parameter T is greater than a fifth preset value T3 or not, wherein the fifth preset value T3 is greater than or equal to a fourth preset value T2, if so, starting the air cooling system, and if not, returning to the step S3.
Therefore, in the battery heat dissipation method, the battery temperature is controlled by preferentially using forced air cooling under the condition that the battery temperature change rate is low but the average temperature is high, the mode is most economical and feasible, and the energy consumed on a heat dissipation system is minimum, so that the continuation of the journey of the electric automobile is guaranteed. In addition, in the method, liquid cooling heat dissipation is preferably selected only under the condition that the temperature change of the battery is severe. Therefore, the battery heat dissipation method has the advantages that the battery pack has two heat dissipation modes of forced air cooling and liquid cooling, the most economical cooling mode can be selected preferably according to the temperature change condition of the battery, the battery temperature is interfered in advance according to the acceleration of the temperature change of the battery, the battery can be ensured to work in a proper temperature range all the time, the performance of the battery is ensured not to be influenced by the temperature change, and the performance of the battery is exerted to the maximum extent. And because the forced air cooling and the liquid cooling are reasonably adopted according to the actual temperature change condition of the battery, better cooling efficiency can be ensured, and the purposes of economy and energy conservation can be achieved.
The battery heat dissipation device provided by the embodiment of the invention comprises a liquid cooling system, an air cooling system, a measuring unit and a control unit. The measuring unit is used for measuring a temperature parameter T of a preset position of the battery pack; the liquid cooling system is used for cooling the battery pack; the air cooling system is used for cooling the battery pack; the control unit is used for executing the steps S2 to S6 of the battery heat dissipation method.
Referring to fig. 2 to 5, a battery pack according to an embodiment of the present invention includes alower case 2 and anupper cover 1, wherein theupper cover 1 and thelower case 2 are fastened to form a cavity for accommodating abattery module 5; the bottom of thelower case 2 is provided with anair circulation path 22 in an air cooling system, and acoolant circulation path 21 in a liquid cooling system. Here, the term "battery module" as used herein means: more than one battery monomer is combined in a series connection, parallel connection or series-parallel connection mode and used as a combined body of a power supply.
Specifically, twobattery modules 5 are preferably arranged in one battery pack, three temperature sensors are arranged in eachbattery module 5, the three temperature sensors are respectively located at the positive end measuring position, the middle measuring position and the negative end measuring position of thebattery module 5, a total of six temperature sensors are provided, and the arithmetic average value of the temperatures detected by the six temperature sensors is recorded as the temperature parameter T.
Referring to fig. 4 and 5, theair circulation path 22 is a through-groove structure formed by recessing the bottom plate of thelower case 2, and thebattery modules 5 are respectively disposed at two sides of theair circulation path 22 in thelower case 2, that is, twobattery modules 5 are arranged in parallel in thelower case 2 of the battery pack and are right at the left and right sides of theair circulation path 22; thecoolant circulation path 21 is a flat through-hole structure provided in the bottom plate of thelower case 2 and located directly below thebattery modules 5.
Specifically, referring to fig. 5, the bottom of thelower housing 2 includes a first vertical side plate, a first horizontal panel, a first vertical panel, a second horizontal panel, a second vertical panel, a third horizontal panel, and a second vertical side plate, which are connected in sequence. Wherein:
the first vertical side plate and the first vertical panel are respectively positioned above two sides of the first horizontal panel to form a first mounting cavity for accommodating the first battery module;
the second vertical panel and the second vertical side plate are respectively positioned above two sides of the third horizontal panel to form a second mounting cavity for accommodating a second battery module;
the first horizontal panel and the third horizontal panel are respectively provided with a coolingliquid circulation path 21;
the bottom recess formed by the first vertical panel, the second horizontal panel and the second vertical panel is anair flow path 22.
Preferably, the flat through-hole structure is formed by sealing the sealingplate 6 with the groove on the outer side of thelower case 2. Further, the cross-sectional shape of thecoolant flow path 21 is preferably set to a flat rectangle whose horizontal side is a long side and vertical side is a short side in order to ensure the largest coverage area of the coolant at the bottom of thelower case 2 as possible.
That is, theair circulation path 22 is a groove structure integrally cast at the bottom of thelower casing 2, is located at the outer side of thelower casing 2, has a relatively large groove cross section, and forms an air cooling system together with thefan 4. The coolingliquid circulation path 21 is a groove structure integrally cast and formed at the bottom of thelower shell 2, is located at the outer side of thelower shell 2, has a relatively small groove section, is sealed by a sealingplate 6 to form a through hole type cavity, and is then connected with a cooling liquid circulation system to form a liquid cooling system.
Specifically, the sealingplate 6 and thelower housing 2 may be welded together by gas shielded welding, friction stir welding, or the like, thereby ensuring that the cooling liquid does not leak.
Specifically, referring to fig. 2 to 4, anair circulation path 22 is disposed in the middle of the bottom of thelower housing 2, two sides of theair circulation path 22 are respectively provided with aconnector 3, theconnector 3 is a standard structural member, and is provided with an inlet and an outlet for connecting an external coolant circulation pipeline; eachinterface 3 connects twocoolant flow paths 21 in parallel with anair flow path 22. Thus, the twocoolant circulation paths 21 communicating with thesame port 3, theport 3, and the external coolant circulation line connected to theport 3 constitute a liquid cooling system.
Specifically, referring to fig. 3 and 4, theair circulation path 22 is located in the middle area of the bottom side of thelower casing 2, and is a through groove structure recessed from the bottom surface to the casing, which is a preset structure of thelower casing 2 itself. The outer side of thelower shell 2 is fixedly connected with thefan 4, and the air outlet of thefan 4 is opposite to one end of theair circulation path 22 to form an air cooling system, so that most of the air quantity of thefan 4 can flow through theair circulation path 22.
Specifically, a gap between the inner surface of thelower case 2 and thebattery module 5 is filled with a thermally conductive paste. Specifically, referring to fig. 5, the bottom surface, the left side surface and the right side surface of thebattery module 5 and thelower case 2 fill the gap with the heat conductive adhesive, so that the contact area between thebattery module 5 and thelower case 2 is large and the heat conductivity is good, and thelower case 2 is integrally used as a heat sink for thebattery module 5.
Specifically, theupper cover 1 is made of a high-molecular composite material, and is molded by injection molding, so that the light weight effect is obvious; thelower shell 2 is made of aluminum alloy and is formed by die casting, and the lower shell has good heat conduction performance.
Specifically, the battery pack is provided with the battery heat dissipation device and adopts the battery heat dissipation method.
In summary, the battery heat dissipation method, the battery heat dissipation device and the battery pack provided by the embodiments of the present invention have both the forced air cooling function and the liquid cooling function, and can switch between the two cooling modes as required, thereby improving the working efficiency of the cooling system and reducing the energy consumption.
It should be noted that, in other embodiments, the balance between the cooling effect and the energy saving can also be achieved to some extent by adjusting the variable factors of the battery cooling system, such as the flow rate, the temperature of the coolant, and the rotation speed of the fan. However, since the power of the air conditioner compressor is significantly higher than that of the fan, the energy requirement is significantly higher than that of the fan, and the energy-saving effect of the battery heat dissipation method and device cannot be achieved.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.