Secondary battery module and secondary battery cooling device

Abstract

The present invention provides a secondary battery module and a secondary battery cooling device that can improve overall cooling efficiency by providing the same cool air without bias to multiple secondary batteries by making the distribution of the cold air released from the cooling plate, which is in close contact with the secondary battery, uniform across the entire surface of the cooling plate. [Solution] The secondary battery module includes a secondary battery assembly composed of multiple secondary batteries, and a cold air transmission unit that is in close contact with the secondary battery assembly and allows a cooling fluid supplied from the outside to pass through, thereby transmitting the cold air of the cooling fluid to the secondary battery assembly. The cold air transmission unit has a cooling fluid passage with an inlet and an outlet through which the cooling fluid passes, and the fluid flow cross-sectional area of ​​the cooling fluid passage widens from the inlet to the outlet.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery, and more particularly to a secondary battery module and a secondary battery cooling device. [Background technology]

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Generally, secondary batteries consist of an electrode assembly comprising a positive electrode plate, a negative electrode plate, and a separator, and an outer casing (battery can or case) that houses it. The electrode assembly can be classified into roll type and stack type depending on the stacking configuration of the electrode plates and separator. The roll type is called a jelly roll, and the stack type is called a stack. Secondary batteries can also be classified into pouch type, cylindrical type, prismatic type, etc., depending on the material and shape of the outer casing.

[0003] On the other hand, secondary battery modules, which are composed of multiple secondary batteries linked together, generate heat from within during the charging and discharging processes. If this heat is not quickly dissipated, the battery performance deteriorates, and in severe cases, it can lead to thermal runaway. For this reason, secondary battery modules include a cooling plate. The cooling plate has a structure that transmits cool air to the secondary batteries while being in close contact with them. However, conventional cooling plates have the disadvantage of not being able to uniformly transmit cool air to the secondary batteries, resulting in poor cooling efficiency.

[0004] The information disclosed above in the background art of such inventions is merely for the purpose of improving understanding of the background of the present invention, and therefore may include information that does not constitute prior art. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention was created to solve the above problems and aims to provide a secondary battery module and a secondary battery cooling device that can improve overall cooling efficiency by providing the same cool air without bias to multiple secondary batteries. [Means for solving the problem]

[0006] A secondary battery module according to one feature of the present invention for solving the above problems includes a secondary battery assembly composed of a plurality of secondary batteries, and a cold air transmission unit that is in close contact with the secondary battery assembly and allows a cooling fluid supplied from the outside to pass through, thereby transmitting the cold air of the cooling fluid to the secondary battery assembly. The cold air transmission unit has an inlet and an outlet, forming a cooling fluid passage through which the cooling fluid passes, and the fluid flow cross-sectional area of ​​the cooling fluid passage is characterized by widening from the inlet to the outlet.

[0007] Furthermore, a secondary battery cooling device according to another feature of the present invention for solving the above problems includes a cold air transmission unit installed in close contact with a secondary battery assembly composed of multiple secondary batteries, and a cooling fluid circulation unit that passes a cooling fluid through the cold air transmission unit. The cold air transmission unit has an inlet and an outlet through which a cooling fluid passage is formed, and the fluid flow cross-sectional area of ​​the cooling fluid passage widens from the inlet to the outlet.

[0008] However, the technical problems and solutions that the present invention aims to solve are not limited to those described above, and other problems and solutions not mentioned can be clearly understood by those skilled in the art from the description of the invention below. [Effects of the Invention]

[0009] As described above, the secondary battery cooling device of the present invention has a uniform distribution of cold air emitted from the cooling plate that is in close contact with the secondary battery. Therefore, it can provide the same cold air without bias to multiple secondary batteries, thereby improving the overall cooling efficiency.

[0010] However, the effects that can be obtained from the present invention are not limited to the above-described effects, and other technical effects that are not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

Brief Description of Drawings

[0011] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described later, serve to further understand the technical idea of the present invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

[0012] [Figure 1] It is a perspective view showing the basic structure of a secondary battery cooled by a secondary battery cooling device according to an embodiment of the present invention. [Figure 2] It is a diagram schematically showing the overall configuration of a secondary battery cooling device according to an embodiment of the present invention. [Figure 3] It is a plan sectional view of a cooling plate in a secondary battery cooling device according to an embodiment of the present invention. [Figure 4] It is a sectional view taken along line A-A of FIG. 3. [Figure 5] It is a plan sectional view showing a modified example of the cooling plate shown in FIG. 3. [Figure 6] It is a sectional view taken along line B-B of FIG. 5. [Figure 7] It is a plan view for explaining another example of the cooling plate in a secondary battery cooling device according to an embodiment of the present invention. [Figure 8] It is a sectional view taken along line C-C of FIG. 7. [Figure 9] It is a diagram for explaining the role of the cooling water deceleration groove in the cooling plate shown in FIG. 8. [Figure 10] It is a plan sectional view showing another example of the cooling plate in a secondary battery cooling device according to an embodiment of the present invention. [Figure 11] It is an exploded perspective view showing another example of the cooling plate in a secondary battery cooling device according to an embodiment of the present invention. [Figure 12] Figure 11 is a cross-sectional view of the cooling plate. [Figure 13] Figure 11 shows the cooling plate as viewed from the inlet and outlet directions. [Figure 14] This is an exploded perspective view showing yet another modification of the cooling plate in a secondary battery cooling device according to one embodiment of the present invention. [Figure 15] Figure 14 shows cross-sectional views of the first and second main bodies. [Figure 16] This figure shows the welding process between the first and second main bodies shown in Figure 14. [Figure 17] This is a perspective view of a secondary battery pack to which a secondary battery module according to one embodiment of the present invention is applied. [Figure 18] This figure shows a vehicle to which the secondary battery pack shown in Figure 17 is applied. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but in accordance with the principle that inventors can appropriately define the concepts of terms in order to best describe their invention, they should be interpreted in a manner and concept consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described herein and the configurations shown in the drawings represent only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that there are a variety of equivalents and modifications that can be substituted for them at the time of filing.

[0014] Furthermore, as used herein, “comprise, include” and / or “comprising, including” identify the presence of the shapes, figures, steps, actions, members, elements, and / or groups thereof mentioned, and do not exclude the presence or addition of one or more other shapes, figures, actions, members, elements, and / or groups thereof.

[0015] Furthermore, in order to facilitate understanding of the present invention, the attached drawings may not be shown to actual scale, and the dimensions of some components may be exaggerated. Note that identical components in different embodiments may be assigned the same reference numeral.

[0016] The statement that two comparison subjects are "identical" means that they are "substantially identical." Therefore, substantially identical may include deviations that are considered low in this industry, for example, deviations of 5% or less. Also, the uniformity of a parameter in a given domain may mean that it is uniform from an average perspective.

[0017] Even though terms such as "first," "second," etc., are used to describe a variety of components, it goes without saying that these components are not limited by these terms. These terms are simply used to distinguish one component from another, and it goes without saying that, unless otherwise stated, the first component may be the second component.

[0018] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0019] The placement of any configuration "above (or below)" or "above (or below)" a configuration means not only that the configuration is placed in contact with the upper (or lower) surface of the configuration, but also that other configurations may be interposed between the configuration and any configuration placed above (or below) it.

[0020] Furthermore, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that the components may be directly connected or linked to each other, but may also be "interposed" between each component or each component may be "connected," "coupled," or "linked" through other components.

[0021] As used herein, the terms "and / or" include any and all combinations of one or more of the items listed relating to the invention. Furthermore, when describing embodiments of the invention, the use of "may also" applies to "one or more embodiments of the invention." Expressions such as "one or more" and "one or more" preceding an element list modify the entire element list, not individual elements of the list.

[0022] Throughout the specification, when "A and / or B" is used, it means A only, B only, or A and B unless otherwise specified, and when "C~D" is used, it means C or greater and D or less unless otherwise specified.

[0023] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0024] The term “use” can be considered synonymous with the term “utilize.” As used herein, “substantially,” “about,” and similar terms are used as approximations, not terms of degree, to account for the intrinsic variability of measured or calculated values ​​as perceived by the general art in the relevant field.

[0025] In this specification, terms such as first, second, third, etc., are used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, drawing layer, or section from other elements, components, regions, drawing layers, or sections. Accordingly, the first elements, components, regions, layers, or sections discussed below may be named second elements, components, regions, layers, or sections, to the extent that they do not depart from the teachings of the exemplary embodiments.

[0026] When illustrating elements or features, spatially relative terms such as "beneath," "below," "lower," "above," and "upper" are used in the specification to facilitate explanation of the relationship between one element or feature and another. Spatially relative positions are understood to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the drawing is inverted, other elements are understood as "below" or "below," and the described element as "above" or "upper" of the other elements. Therefore, the term "below" can encompass both the up and down directions.

[0027] The terms used herein are for describing embodiments of the present invention and are not intended to limit the invention.

[0028] Figure 1 is a perspective view showing the basic structure of a secondary battery cooled by a secondary battery cooling device according to one embodiment of the present invention. The secondary battery 15 shown in Figure 1 is of the rectangular type.

[0029] The case 15a forms the overall appearance of the prismatic battery and may be made of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel. The case 15a can also provide a space for housing the electrode assembly.

[0030] The cap assembly 15b may include a cap plate 15c that covers the opening of the case 15a. In some embodiments, the case 15a and the cap plate 15c may be made of a conductive material. Here, a first terminal 15d and a second terminal 15e may be electrically connected to internal positive and negative electrode tabs, respectively, and installed to be exposed on the outside of the cap plate 15c.

[0031] An electrolyte inlet 15f may be formed in the cap plate 15c, and a gas exhaust hole 15g is open to it. A vent, or gas exhaust device 15h, may be joined to this gas exhaust hole 15g. The gas exhaust device 15h opens due to gas generated inside the battery, causing a degassing effect.

[0032] For reference, the materials that can be used in the aforementioned secondary battery are as follows:

[0033] As the positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithium intercalation compound) can be used. Specifically, one or more composite oxides of lithium with a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0034] The composite oxide may be a composite oxide of a lithium transition metal. Specific examples include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free nickel-manganese-based oxides, or combinations thereof.

[0035] As an example, a compound represented by any one of the following formulas can be used. Li 1-b-c , α , e , c , a , 1 , 1-b , b , b , α , b , c , a , b , d , a , c , 2-α , a , b , b , 2-α , a , a A 1-b X b O 2-c D c (0.90 ≤ a ≤  1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05), Li a Mn 2-b X b O 4-c D c (0.90 ≤ a ≤  1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05), Li a Ni 1-b-c Co b X c O 2-α D α (0.90 ≤ a ≤  1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 < α < 2), Li a Ni 1-b-c Mn b X c O 2-α D α (0.90 ≤ a ≤  1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 < α < 2), Li a Ni b Co c L 1 d G e O2(0.90 ≤ a ≤  1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.1), Li a NiG b O2(0.90 ≤ a ≤  1.8, 0.001 ≤ b ≤ 0.1), Li a CoG b O2(0.90 ≤ a ≤  1.8, 0.001 ≤ b ≤ 0.1), Li a Mn 1-b G b O2(0.90 ≤ a ≤  1.8, 0.001 ≤ b ≤ 0.1), Li a Mn2Gb O4 (0.90≦a≦1.8, 0.001≦b≦0.1), Li a Mn 1-g G g PO4(0.90≦a≦1.8, 0≦g≦0.5), Li (3-f) Fe2(PO4)3(0≦f≦2), Li a FePO4 (0.90 ≤ a ≤ 1.8).

[0036] In the above formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 This is Mn, Al, or a combination of these.

[0037] A positive electrode for a secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and further include a binder and / or a conductive material.

[0038] The content of the positive electrode active material is 90% to 99.5% by weight relative to 100% by weight of the positive electrode active material layer, and the content of the binder and conductive material may be 0.5% to 5% by weight, respectively, relative to 100% by weight of the positive electrode active material layer.

[0039] Al can be used as the current collector, but is not limited to it.

[0040] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material that can be doped and dedoped with lithium, or a transition metal oxide.

[0041] As substances that can reversibly intercalate / deintercalate lithium ions, carbon-based negative electrode active materials can be included, for example, crystalline carbon, amorphous carbon, or combinations thereof. Examples of the crystalline carbon can include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon can include soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0042] As substances that can be doped and undoped with lithium, Si-based negative electrode active materials or Sn-based negative electrode active materials can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-based alloy, or combinations thereof.

[0043] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite can be in a form in which amorphous carbon is coated on the surface of silicon particles.

[0044] The silicon-carbon composite can further contain crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of this core.

[0045] The negative electrode for a lithium secondary battery includes a current collector and a negative electrode active material layer located on this current collector. The negative electrode active material layer contains a negative electrode active material and can further contain a binder and / or a conductive material.

[0046] For example, the negative electrode active material layer can contain 90 wt% to 99 wt% of the negative electrode active material, 0.5 wt% to 5 wt% of the binder, and 0 wt% to 5 wt% of the conductive material.

[0047] The binder can be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, it may further contain a cellulosic compound that can impart viscosity.

[0048] As the negative electrode current collector, copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof can be selected.

[0049] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0050] The aforementioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0051] The non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, a non-quantum solvent, or a combination thereof, and can be used alone or in a mixture of two or more.

[0052] Furthermore, when using carbonate-based solvents, cyclic carbonates and linear carbonates can be mixed and used together.

[0053] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators may be polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers thereof.

[0054] The separator may include a porous substrate and a coating layer comprising organic, inorganic, or a combination thereof located on one or both sides of the porous substrate.

[0055] The aforementioned organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0056] The inorganic material may include, but is not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, bohemite, and combinations thereof.

[0057] The organic and inorganic materials may be present mixed in a single coating layer, or in a form in which a coating layer containing organic materials and a coating layer containing inorganic materials are laminated together.

[0058] Multiple secondary batteries 15 having the above configuration can be combined to form one secondary battery assembly (21 in Figure 2). The secondary battery assembly 21 can form one secondary battery module 20 together with the cooling plate 40. The secondary battery assembly 21 can also be a cooling target that is cooled by the cooling plate 40.

[0059] Figure 2 is a schematic diagram showing the overall configuration of a secondary battery cooling device 30 according to one embodiment of the present invention.

[0060] The secondary battery cooling device 30 may include a cold air transmission section and a cooling fluid circulation section. The cold air transmission section is installed in close contact with the secondary battery assembly 21 and plays the role of transmitting cold air to the secondary battery assembly 21. In this embodiment, a cooling plate 40 is used as the cold air transmission section. The cooling plate 40 will be described later.

[0061] The cooling fluid circulation section can pass the cooling fluid through the cold air transfer section. The cooling fluid circulation section may include a cooler 23 and a circulation pump 25. The cooler 23 may be connected to the cold air transfer section via a circulation pipe 26. The cooler 23 plays the role of cooling the cooling fluid after it has passed through the cold air transfer section and completed heat exchange. The circulation pump 25 can also continuously circulate the cooling fluid. In particular, the flow rate per unit time of the cooling fluid circulated by the circulation pump 25 is the same at any point. The cooling fluid may include cooling water.

[0062] Figure 3 is a plan cross-sectional view of a cooling plate 40, which is a cold air transfer section in a secondary battery cooling device 30 according to one embodiment of the present invention, and Figure 4 is a cross-sectional view taken along line AA of Figure 3.

[0063] The cooling plate 40 is in close contact with the bottom surface of the secondary battery assembly 21 and can transmit the cool air of the cooling fluid to the secondary battery assembly while allowing the cooling fluid supplied through the circulation pipe 26 to pass through.

[0064] The cooling plate 40 has an inlet 43 and an outlet 47, providing a cooling fluid passage through which the cooling fluid passes. In particular, the fluid flow cross-sectional area of ​​the cooling fluid passage widens from the inlet 43 to the outlet 47. That is, it widens in the direction of arrow a in Figure 3.

[0065] The cooling plate 40 has a plate-like appearance with a certain thickness and can be placed at the bottom of the secondary battery assembly 21. The cooling plate 40 is in close contact with the bottom surface of the secondary battery assembly 21 and is capable of heat conduction.

[0066] In particular, the heat transfer area of ​​each secondary battery 15 constituting the secondary battery assembly 21 to the cooling plate 40 is all the same. In other words, the contact area of ​​each secondary battery 15 to the upper surface of the cooling plate 40 is all the same.

[0067] The reason for configuring the contact area to be the same is that, if the cold air released from the top of the cooling plate 40 is not locally concentrated but uniform across the entire surface, it is possible to transfer the same amount of cold air to each secondary battery 15.

[0068] The cooling fluid passage may include a first passage 41a and a second passage 41e, separated by a partition wall 45, as shown in Figure 3. The first passage 41a and the second passage 41e may be connected via a connecting passage 41c. The first passage 41a is open to the inlet 43 side, and the second passage 41e is open to the outlet 47 side.

[0069] Therefore, the cooling fluid that flows into the inlet 43 via the circulation pipe 26 can exchange heat with the cooling plate 40 while flowing through the first passage 41a, the connecting passage 41c, and the second passage 41e. The cooling plate 40, heated by the heat from the secondary battery assembly 21, exchanges heat with the cooling fluid.

[0070] Furthermore, the first passage 41a and the second passage 41e can be arranged horizontally to each other, that is, they can have the same height. Since the first passage 41a and the second passage 41e have the same height, the first passage, the second passages 41a and 41e can have the same spacing as the secondary battery assembly. That is, the spacing between the first passage 41a and the secondary battery assembly 21 can be identical to the spacing between the second passage 41e and the secondary battery assembly 21.

[0071] As described above, the cooling plate 40 can dissipate heat from the secondary battery assembly 21 while being in close contact with the bottom surface of the secondary battery assembly 21. The cooling fluid absorbs heat from the secondary battery assembly 21 and is then discharged through the outlet 47. The cooling fluid passage has a structure that widens from the inlet 43 to the outlet 47, allowing for uniform cooling of the secondary battery assembly 21. In other words, the same amount of cooling air is transmitted to each secondary battery 15, preventing cooling imbalances.

[0072] On the other hand, referring to Figure 4, it can be seen that the area of ​​the outlet 47 is relatively larger than the area of ​​the inlet 43. As mentioned above, the fluid flow cross-sectional area of ​​the cooling fluid passage inside the cooling plate 40 widens from the inlet 43 to the outlet 47, so the flow cross-sectional area of ​​the outlet 47 is relatively larger.

[0073] Because of this difference in flow cross-sectional area, the flow velocity of the cooling fluid exiting to the outlet 47 is relatively slower than the flow velocity of the cooling fluid entering the inlet 43. A slower flow velocity can mean that the heat exchange time with the heat source is relatively longer.

[0074] The cooling fluid newly flowing in through the inlet 43 has not yet begun heat exchange, so its temperature is lower (relatively speaking, compared to the cooling fluid leaving through the outlet 47), and the time required for heat exchange may be shorter than on the outlet 47 side. Let ΔT1 be the temperature difference between the cooling fluid at the inlet 43 and the secondary battery assembly.

[0075] As the cooling fluid flows in the direction of arrow a, its temperature gradually rises, so the temperature difference ΔT2 between the cooling fluid and the secondary battery assembly 21 at the outlet 47 becomes smaller than ΔT1. In a situation where the temperature difference is small, the heat exchange time must be longer to perform the same amount of heat exchange. Furthermore, in order to relatively extend the heat exchange time as one approaches the outlet 47, the flow cross-sectional area of ​​the cooling fluid is made wider from the inlet 43 to the outlet 47. If the flow rate per unit time is the same, a wider flow cross-sectional area means that the time spent passing through the flow field increases.

[0076] In other embodiments, the flow cross-sectional area of ​​the first passage 41a can be kept constant, while the flow cross-sectional area of ​​the second passage 41e can be designed to increase as it moves downstream. Conversely, the flow cross-sectional area of ​​the second passage 41e can be kept constant, while the flow cross-sectional area of ​​the first passage 41a can be designed to increase as it moves downstream.

[0077] Figure 5 is a plan view showing a modified example of the cooling plate 40 shown in Figure 3, and Figure 6 is a cross-sectional view of Figure 5 along line BB.

[0078] As shown in the figure, multiple expansion grooves 41g may be formed in the second passage 41e. The expansion grooves 41g are grooves with a rounded bottom surface, and their width and depth may gradually increase as they approach the outlet 47. By applying the expansion grooves 41g, the cooling fluid passing through the second passage 41e and approaching the outlet 47 can be decelerated more quickly.

[0079] The expanded groove 41g having the above shape can more effectively embody the mechanism by which the cooling fluid is decelerated as it approaches the outlet 47. The cooling fluid flows in through the inlet 43 at a relatively high speed, but due to the expanding shape of the expanded groove 41g, the flow velocity can decrease even more rapidly as it passes through the second passage 41e. Such flow characteristics can occur because the flow cross-sectional area of ​​the cooling fluid increases, and the cooling fluid occupies more space, thus reducing the flow velocity.

[0080] Furthermore, as the flow velocity of the cooling fluid slows down towards the outlet 47, the time during which the cooling fluid exchanges heat with the secondary battery assembly 21 increases, enabling more efficient and uniform cooling. The heat exchange that takes place relatively quickly at the inlet 43 increases as the cooling fluid approaches the outlet 47 due to the decrease in its velocity, thereby improving the cooling efficiency.

[0081] The structural characteristics shown in Figure 5 play a crucial role in ensuring efficient heat exchange through changes in the flow cross-sectional area and regulation of the cooling fluid velocity. The shape, size, and installation position of the expansion groove 41g can be implemented in various ways according to other embodiments.

[0082] Furthermore, even in the case of the type of cooling plate 40 shown in Figures 5 and 6, various modifications of the first passage 41a and the second passage 41e are possible. For example, while maintaining a constant flow cross-sectional area of ​​the first passage 41a, the flow path cross-sectional area of ​​the second passage 41e can be designed to increase as it approaches the outlet 47. Conversely, the second passage 41e can be kept constant, and the flow cross-sectional area of ​​the first passage 41a can be widened to enhance the cooling effect downstream.

[0083] Such modifications allow for further optimization of the performance of the cooling plate 40 by enabling adjustment of the cooling fluid flow rate and heat exchange time in various ways.

[0084] Figure 7 is a plan view illustrating a cooling plate 40 in a secondary battery cooling device according to another embodiment of the present invention, Figure 8 is a cross-sectional view of Figure 7 along line CC, and Figure 9 is a diagram illustrating the role of the cooling water deceleration groove in the cooling plate shown in Figure 8.

[0085] As shown in the figure, a flow velocity sensing element may be formed on the inward-facing surface of the second passage 41e. The flow velocity sensing element can play a role in further reducing the flow velocity of the cooling fluid passing through the second passage 41e toward the outlet 47.

[0086] A reduction groove 41k may be used as the flow velocity sensing section. The reduction groove 41k can take the shape of, for example, a V-cutting type notch groove. The reduction groove 41k can disturb the flow of the cooling fluid passing through the second passage 41e and slow down its passage speed. Since a portion of the fluid passing through the second passage 41e must enter the reduction groove 41k and then exit, the average streamline length of the cooling fluid is increased, thereby slowing down its passage speed.

[0087] To elaborate further on the above explanation, the flow velocity sensing unit is responsible for further reducing the flow velocity when the cooling fluid passes through the second passage 41e and flows to the outlet 47. This structural feature solves the problem of insufficient heat exchange time due to the cooling fluid flowing too quickly.

[0088] Furthermore, the deceleration groove 41k, which is applied as a flow velocity sensing section, can take the shape of a V-cut notch groove and effectively disrupt the flow of fluid passing through the second passage 41e. In other words, the deceleration groove 41k can alter the fluid flow so that the cooling fluid cannot pass through the passage in a straight line, thereby complicating the flow of the cooling fluid and reducing its passage velocity.

[0089] The operating principle of the deceleration groove 41k is as follows: A portion of the cooling fluid passing through the second passage 41e enters the deceleration groove 41k, and thereafter, the flow velocity becomes turbulent and the streamline of the flow lengthens. As the streamline length increases, the time the fluid spends passing through the entire passage increases, which ultimately has the effect of lowering the average velocity of the cooling fluid. The fluid that has entered the deceleration groove decreases in velocity as it exits the deceleration groove again, thereby allowing the cooling fluid to remain inside the second passage for heat exchange for an even longer period of time.

[0090] Furthermore, in addition to simply reducing the flow velocity, the deceleration groove 41k creates turbulence in the flow of the cooling fluid, allowing for more effective heat transfer between the cooling fluid and the inner wall of the cooling plate. Turbulent flow increases contact between the fluid and the wall surface, maximizing heat transfer efficiency.

[0091] Such a design offers significant advantages, particularly in more efficient thermal management of secondary batteries. Since secondary batteries generate heat during operation, it is essential to regulate the flow rate of the cooling fluid to ensure sufficient heat exchange time. Structures like the reduction groove 41k can play a crucial role in preventing the cooling fluid from flowing too quickly, thereby extending the heat exchange time with the secondary battery assembly 21 and improving overall cooling performance.

[0092] Figure 10 is a plan cross-sectional view showing a cooling plate 40 in a secondary battery cooling device according to the present invention and some other embodiments thereof.

[0093] As shown in the figure, a plurality of stream guides 49 may be provided inside the second passage 41e. The stream guides 49 are plate-shaped members of a certain thickness, and their lower ends may be fixed to the bottom of the second passage 41e and their upper ends to the ceiling. The stream guides 49 can guide a linear flow of cooling fluid into a curved flow.

[0094] The cooling fluid is guided by the stream guide 49, for example, by meandering repeatedly in the left-right direction. As the streamlines of the cooling fluid lengthen, the time it spends passing through the second passage 41e increases, thereby extending the time during which heat exchange is possible.

[0095] As described above, the stream guide 49 is composed of a plate-like member having a certain thickness and can be fixed vertically from the bottom to the top of the second passage 41e. As described above, the multiple stream guides 49 fixed to the second passage are intended to improve the overall cooling efficiency by preventing the cooling fluid from simply flowing in a straight line and by controlling its flow. The stream guides 49 play a role in causing the cooling fluid to meander, thereby bending the cooling fluid as it passes through the second passage 41e from side to side.

[0096] The main advantage that can be obtained by making the flow of the cooling fluid meander is the increase in the length of the streamlines. Generally, when a fluid passes quickly in a straight path, the heat exchange time is short and the cooling effect is limited. However, when a curved flow is induced by the stream guide 49, the streamlines of the cooling fluid become longer, and the time it takes to pass through the second passage 41e naturally increases. This further increases the heat exchange time between the cooling fluid and the cooling plate 40, enabling effective heat dissipation.

[0097] Furthermore, the stream guide 49 can not only slow down the flow of the cooling fluid but also generate turbulence. As the cooling fluid meanders along the stream guide 49, its flow is obstructed and becomes more complex, causing it to come into contact with the walls of the cooling plate more frequently. This promotes heat transfer between the walls and the fluid, further enhancing cooling performance. Generally, turbulence has a higher heat transfer coefficient than laminar flow, so the stream guide 49 can play a crucial role in maximizing cooling performance.

[0098] The spacing and shape of the stream guides 49 can be adjusted in various ways. For example, if the stream guides 49 are arranged more closely together, the fluid will have to change direction more frequently, which can significantly slow down the flow velocity. Conversely, by widening the spacing or adjusting the height of the stream guides, appropriate turbulence can be generated while maintaining some flow velocity. Such design flexibility can be optimized according to the cooling requirements.

[0099] Ultimately, the aforementioned stream guide 49 maximizes the heat exchange time between the cooling fluid and the cooling plate by causing the cooling fluid flow to meander and extending the length of the streamlines, thereby enabling stable thermal management of the secondary battery.

[0100] Figure 11 is an exploded perspective view showing a cooling plate 40 in a secondary battery cooling device according to yet another embodiment of the present invention, and Figure 12 is a plan cross-sectional view of the cooling plate shown in Figure 11. Figure 13 is a view of the cooling plate of Figure 11 from the inlet and outlet directions.

[0101] As shown in Figures 11 to 13, a heat exchange liner 51 may be added to the second passage 41e of the cooling plate 40. The heat exchange liner 51 may be made of copper or aluminum as a heat transfer member to improve heat transfer performance.

[0102] The heat exchange liner 51 is fixed inside the second passage 41e, allowing the cooling fluid to pass through it. Furthermore, the contact area of ​​the heat exchange liner 51 with the cooling fluid can be increased as it moves towards the outlet 47.

[0103] The heat exchange liner 51 may include a guide tunnel 51a and a plurality of heat transfer fins 51c. The guide tunnel 51a may have the shape of a rectangular duct and may be tightly coupled to the inner surface of the second passage 41e. The heat exchange liner 51 may be coupled to the guide tunnel 51a by welding.

[0104] Furthermore, the heat transfer fins 51c, while fixed inside the guide tunnel 51a, can collect cold air from the cooling fluid and transfer it to the guide tunnel 51a. Also, hot air transferred from the secondary battery assembly 21 can be transferred to the heat transfer fins 51c via the guide tunnel 51a. The cooling fluid can exchange heat through the heat transfer fins 51c.

[0105] The number of heat transfer fins 51c can be increased towards the outlet. As shown in Figure 12, the number of heat transfer fins 51c is 2 rows at the inlet of the second passage 41e, 3 rows thereafter, and 5 rows at the outlet.

[0106] As mentioned above, increasing the number of heat transfer fins 51c towards the end expands the heat exchange area and provides uniform cool air. As noted, the temperature of the cooling fluid decreases towards the outlet 47, so expanding the heat exchange area is necessary to provide uniform cool air. The number of heat transfer fins 51c can be applied in different ways depending on the various embodiments.

[0107] As described above, the cooling plate 40 has a heat exchange liner 51 in the second passage 41e, which significantly improves its heat transfer performance. As mentioned, the heat exchange liner 51 is made of a highly thermally conductive material such as copper or aluminum, which further enhances the heat transfer efficiency and enables more uniform cooling of the secondary battery assembly 21. Furthermore, the heat exchange liner 51 has a structure in which the contact area with the cooling fluid expands as it moves towards the outlet 47, which further improves the heat exchange efficiency.

[0108] Furthermore, the number of heat transfer fins 51c increases towards the outlet, and by adjusting the number of heat transfer fins 51c, it is possible to meet diverse cooling requirements and provide optimal cooling performance tailored to various usage environments and operating conditions.

[0109] Figure 14 is an exploded perspective view showing yet another modification of the cooling plate 40 in a secondary battery cooling device 30 according to one embodiment of the present invention; Figure 15 is a cross-sectional view of the first body and the second body 61, 63 of Figure 14; and Figure 16 shows the first body and the second body of Figure 14 welded together.

[0110] As shown in Figure 14, the cooling plate 40, which serves as the cold air transfer section, can also be composed of a first body 61 and a second body 63. By joining the first body 61 and the second body 63, a single cooling plate 40 can be formed.

[0111] As shown in the figure, the cooling plate 40 may include a first body 61 and a second body 63.

[0112] The first body 61 may have an inlet 43 at one end and a first connecting passage 61c on the side of the other end. Furthermore, a first passage 41a may be provided inside the first body 61. The cooling fluid pumped by the circulation pump 25 flows into the first passage 41a via the inlet 43 and then exits into the first connecting passage 61c. The flow cross-sectional area of ​​the first passage 41a can also widen from the inlet 43 towards the first connecting passage 61c.

[0113] The second body 63 is a paired element with the first body 61 and can be welded to the side of the first body 61. An outlet 47 is formed at one end of the second body 63, and a second connecting passage 63c may be formed at the other end. The second connecting passage 63c is a square hole corresponding to the first connecting passage 61c. When the first body 61 and the second body 63 are joined, the first connecting passage, the second connecting passages 61c and 63c can form a single passage.

[0114] The second connecting passage 63c can receive the cooling fluid that has passed over from the first body 61 and guide it to the second body 63. The cooling fluid guided to the second body 63 can be discharged to the outlet 47 via the second passage 41e. The flow cross-sectional area of ​​the second passage 41e can widen as it approaches the outlet 47.

[0115] Figure 16 shows the state in which the first body 61 and the second body 63 are welded together. The reference numeral w in the drawing indicates the welded area. As shown in the figure, the first body 61 and the second body 63 can be in close contact with each other to form a single cooling plate 40.

[0116] On the other hand, the first body 61 and the second body 63 can be made of different metals. In particular, the thermal conductivity of the second body 63 may be relatively higher than that of the first body 61. For example, the first body 61 can be made of an aluminum alloy, and the second body 63 can be made of a copper alloy.

[0117] Thus, because the thermal conductivity of the second body 63 is higher than that of the first body 61, a more stable and uniform cooling output from the cooling plate 40 can be realized. In other words, although the temperature of the cooling fluid passing through the second passage 41e is relatively lower than the temperature of the cooling fluid passing through the first passage 41a, the amount of heat exchanged with the secondary battery assembly 21 does not decrease below the amount of heat exchanged by the first body 61 because the thermal conductivity of the second body 63 is relatively higher.

[0118] As described above, the cooling plate 40, formed by combining the first body 61 and the second body 63, effectively removes the heat generated by the secondary battery 15. Furthermore, since the thermal conductivity of the second body 63 is relatively higher than that of the first body 61, a more stable and uniform cooling output can be achieved, thereby improving the overall efficiency of the system.

[0119] Figure 17 is a perspective view of a secondary battery pack 18 to which a secondary battery module 20 according to one embodiment of the present invention is applied.

[0120] A secondary battery pack can be manufactured by housing multiple secondary battery modules within a pack housing designed for installation in an actual product. The pack housing may include fasteners and electrical leads necessary for installation in the product. In Figure 17, for illustrative purposes, the busbars for the electrical connection of the secondary batteries, the cooling unit, external terminals, and other related elements are omitted from the illustration. The secondary battery pack can be installed in an automobile. The automobile may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile may include four-wheel drive or two-wheel drive vehicles.

[0121] Figure 18 shows a vehicle to which the secondary battery pack shown in Figure 17 is applied.

[0122] Figure 18 illustrates a secondary battery pack 18 according to one embodiment of the present invention mounted on the underside of an automobile. The automobile operates by receiving power from the secondary battery pack 18 according to one embodiment of the present invention.

[0123] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that a wide range of modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims described below by persons with ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0124] 15: Secondary battery 15a: Case 15b: Cap Assembly 15c: Cap plate 15d: Terminal 1 15e: Terminal 2 15f: Electrolyte inlet 15g: Gas vent 15h: Gas discharge device 15k: Connecting member 18: Rechargeable battery pack 20: Secondary battery module 21: Secondary battery assembly 23:Cooler 25: Circulation pump 26: Circulation pipe 30: Secondary battery cooling device 40: Cooling Plate 41a: First aisle 41c: Connecting passage 41e: Second passage 41g: Expanded groove 41k: Reduction groove 43:Entrance 45: Bulkhead 47: Exit 49: Stream Guide 51: Heat exchange liner 51a: Guide tunnel 51c: Heat transfer fins 61: The first body 61c: First connecting passage 63: The second body 63c: Second connecting passage w: Welding area

Claims

1. A secondary battery assembly consisting of multiple secondary batteries, It includes a cold air transmission unit that is in close contact with the secondary battery assembly, allows a cooling fluid supplied from the outside to pass through, and transmits the cold air of the cooling fluid to the secondary battery assembly, In the cold air transmission section, A cooling fluid passage is formed having an inlet and an outlet, through which the cooling fluid passes, and the fluid flow cross-sectional area of ​​the cooling fluid passage widens from the inlet to the outlet. Secondary battery module.

2. The heat transfer area of ​​each secondary battery constituting the secondary battery assembly with respect to the cold air transfer section is all the same. The cooling fluid passage is partitioned by a partition wall, connected to a connecting passage, and includes a first passage open to the inlet side and a second passage open to the outlet side. The secondary battery module according to claim 1.

3. The cold air transmission section has the shape of a plate and is installed at the bottom of the secondary battery assembly. The first and second passages are arranged horizontally and have the same spacing as the secondary battery assembly. The secondary battery module according to claim 2.

4. The first passage is, The flow cross-sectional area increases as you move from the aforementioned entrance towards the connecting passage. The secondary battery module according to claim 3.

5. The aforementioned second passage is, The flow cross-sectional area increases as you move from the connecting passage towards the aforementioned outlet. The secondary battery module according to claim 3.

6. In the second passage, A flow velocity sensing unit is formed to further reduce the flow velocity of the cooling fluid passing through the second passage. The secondary battery module according to claim 3.

7. Inside the second passage, A heat exchange liner is installed that comes into contact with the cooling fluid, but the contact area with the cooling fluid expands as it moves towards the outlet. The secondary battery module according to claim 3.

8. The aforementioned heat exchange liner is A guide tunnel is provided that is in close contact with the inner surface of the second passage and allows the cooling fluid to pass through. It includes a plurality of heat transfer fins fixed inside the guide tunnel, which collect the cold air of the cooling fluid and transmit it to the guide tunnel, with the number of fins increasing towards the exit, The secondary battery module according to claim 7.

9. The heat transfer area of ​​each secondary battery constituting the secondary battery assembly with respect to the cold air transfer section is all the same. The aforementioned cold air transmission section is A first body having the aforementioned inlet at one end and a first connecting passage at the other end through which cooling fluid is discharged, and providing the first passage, A second body having the outlet at one end and a second connecting passage corresponding to the first connecting passage at the other end, and including a second body that provides the second passage internally and is connected to the first body to constitute a single cold air transmission section, The secondary battery module according to claim 1.

10. The thermal conductivity of the second body is relatively higher than that of the first body. The secondary battery module according to claim 9.

11. A cold air transfer unit is installed in close contact with a secondary battery assembly composed of multiple secondary batteries, The cold air transmission section includes a cooling fluid circulation section that passes a cooling fluid through it, In the cold air transmission section, A cooling fluid passage is formed, having an inlet and an outlet, through which a cooling fluid passes, and the fluid flow cross-sectional area of ​​the cooling fluid passage widens from the inlet to the outlet. Secondary battery cooling device.

12. The heat transfer area of ​​each secondary battery constituting the secondary battery assembly with respect to the cold air transfer section is all the same. The cooling fluid passage is partitioned by a partition wall, connected to a connecting passage, and includes a first passage open to the inlet side and a second passage open to the outlet side. The secondary battery cooling device according to claim 11.

13. The cold air transmission section has the shape of a plate and is installed at the bottom of the secondary battery assembly. The first and second passages are arranged horizontally and have the same spacing as the secondary battery assembly. The secondary battery cooling device according to claim 12.

14. The first passage is, The flow cross-sectional area increases as you move from the aforementioned entrance towards the aforementioned connecting passage. The secondary battery cooling device according to claim 13.

15. The aforementioned second passage is, The flow cross-sectional area increases as you move from the connecting passage towards the outlet. The secondary battery cooling device according to claim 13.

16. In the second passage, A flow velocity sensing unit is formed to further reduce the flow velocity of the cooling fluid passing through the second passage. The secondary battery cooling device according to claim 13.

17. Inside the second passage, A heat exchange liner is installed that comes into contact with the cooling fluid, but whose contact area with the cooling fluid expands as it approaches the outlet. The secondary battery cooling device according to claim 13.

18. The aforementioned heat exchange liner is A guide tunnel is provided that is in close contact with the inner surface of the second passage and allows the cooling fluid to pass through. It includes a plurality of heat transfer fins fixed inside the guide tunnel, which collect the cold air of the cooling fluid and transmit it to the guide tunnel, with the number of fins increasing towards the exit, The secondary battery cooling device according to claim 17.

19. The heat transfer area of ​​each secondary battery constituting the secondary battery assembly with respect to the cold air transfer section is all the same. The aforementioned cold air transmission section is A first body having the inlet at one end and a first connecting passage at the other end through which the cooling fluid is discharged, providing the first passage, A second body having the outlet at one end and a second connecting passage corresponding to the first connecting passage at the other end, and including a second body that provides the second passage internally and is connected to the first body to constitute a single cold air transmission section, The secondary battery cooling device according to claim 11.

20. The thermal conductivity of the second body is relatively higher than that of the first body. The secondary battery cooling device according to claim 19.

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