Heat exchanger for battery cells, and battery module
The heat exchange device with region-specific spring constants addresses non-uniform pressure in battery cells by balancing expansion forces, ensuring consistent contact and thermal uniformity for improved battery performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MAZDA MOTOR CORP
- Filing Date
- 2024-12-27
- Publication Date
- 2026-07-09
AI Technical Summary
Existing battery cells experience non-uniform pressure due to expansion and contraction caused by charging/discharging and temperature changes, making it difficult to maintain consistent contact with cooling bodies.
A heat exchange device with biasing members that generate a pressing force, where the spring constants are set differently across regions to counteract the expansion force, with lower constants in central regions and higher near electrode tabs, ensuring uniform pressure application.
The solution achieves uniform pressure distribution across battery cells, enhancing thermal uniformity and reaction consistency despite expansion and contraction, thereby improving battery performance and lifespan.
Smart Images
Figure 2026115135000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a heat exchange device for cooling a battery cell and a battery module including such a heat exchange device.
Background Art
[0002] In a rechargeable battery module, a plurality of battery cells are combined to increase the capacity. In such a battery module, in order to prevent the battery cells from becoming hot due to heat generation, a cooling body may be interposed between the battery cells. Further, it is known that by pressing the surface of the battery cell with such a cooling body or the like and moderately pressing the laminate of the electrode plate and the composite material, the reactivity can be kept good (see, for example, Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a battery cell, expansion and contraction are repeated due to charging / discharging, temperature changes, etc. Therefore, it is not always easy to press the cell with a uniform pressure.
[0005] The present invention has been made in view of the above points, and an object thereof is to easily improve the uniformity of the pressure applied to the battery cell.
Means for Solving the Problems
[0006] To achieve the above objective, the present invention provides a heat exchange device for a battery cell having a main surface and a contact surface that contacts the battery cell, wherein heat is transferred from the main surface through the contact surface, the contact surface is configured to generate a pressing force that resists a force in the direction that causes the main surface of the battery cell to expand, and the spring constants for the pressing force and the displacement of the contact surface are set to be smaller at a position corresponding to a first region in the central part of the main surface than at a position corresponding to a second region in the periphery.
[0007] The heat exchange device for the battery cell is provided with biasing members that generate a pressing force against the force that causes the main surface of the battery cell to expand, at positions corresponding to the first and second regions on the inner side of the contact surface, and the spring constant of the biasing member provided at the position corresponding to the first region may be set to be smaller than the spring constant of the biasing member provided at the position corresponding to the second region.
[0008] The heat exchanger for the battery cell may have a spring constant set to be greater at the position corresponding to the electrode tab of the battery cell than at the position corresponding to the second region.
[0009] The spring constant at the position corresponding to the electrode tab of the battery cell may be, for example, a spring constant that includes the influence of the rigidity of the heat exchanger housing and / or ribs provided on the housing.
[0010] Furthermore, the present invention relates to a battery module comprising a battery cell having a main surface and a heat exchanger for the battery cell having a contact surface that abuts against the battery cell, wherein heat is transferred from the main surface to the contact surface, the contact surface is configured to generate a pressing force that resists a force in the direction that causes the main surface of the battery cell to expand, and the spring constants for the pressing force and the displacement of the contact surface are set to be smaller at a position corresponding to a first region in the central part of the main surface than at a position corresponding to a second region in the periphery.
[0011] The battery module is provided with biasing members that generate a pressing force to resist the force that causes the main surface of the battery cell to expand, at positions corresponding to the first and second regions on the inside of the contact surface, and the spring constant of the biasing member provided at the position corresponding to the first region may be set to be smaller than the spring constant of the biasing member provided at the position corresponding to the second region.
[0012] The battery module may have a spring constant set to be greater at the position corresponding to the electrode tab of the battery cell than at the position corresponding to the second region.
[0013] The spring constant at the position corresponding to the electrode tab of the battery cell may be, for example, a spring constant that includes the influence of the rigidity of the heat exchanger housing and / or ribs provided on the housing.
[0014] As a result, the effect of the magnitude of the spring constant, as described above, is offset by the magnitude of the displacement due to the expansion and contraction of the battery cell, thus achieving uniformity of the pressure applied to the main surface of the battery cell. [Effects of the Invention]
[0015] This invention makes it possible to easily improve the uniformity of the pressure applied to the battery cell. [Brief explanation of the drawing]
[0016] [Figure 1] Figure 1 is a schematic plan view showing a battery module 100 according to Embodiment 1. [Figure 2] Figure 2 is a perspective view showing the configuration of the battery cell 110. [Figure 3] Figure 3 is a front view showing the configuration of the heat exchange unit 121. [Figure 4] Figure 4 is a perspective view showing the configuration of spring 131. [Figure 5] Figure 5 is a side view showing an example of deformation of the battery cell 110. [Figure 6] Figure 6 is a schematic plan view showing the battery module 100 according to Embodiment 2. [Figure 7] FIG. 7 is a perspective view showing the configuration of the battery cell 110. [Figure 8] FIG. 8 is a front view showing the configuration of the heat exchange part 121. [Figure 9] FIG. 9 is a plan view showing an example of the deformation of the battery cell 110. [Figure 10] FIG. 10 is an explanatory view showing another example of the spring 131.
Mode for Carrying Out the Invention
[0017] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In each of the following embodiments, components having the same functions as those in other embodiments are denoted by the same reference numerals, and the description thereof will be omitted.
[0018] FIG. 1 is a plan view schematically showing a battery module 100 having a heat exchange device 120 according to Embodiment 1 of the present invention. The battery module 100 includes a housing 101, a plurality of battery cells 110 housed in the housing 101, and a heat exchange device 120.
[0019] The battery module 100 is mounted on an electric vehicle that generates driving force only by a traveling motor (not shown). The battery module 100 may be mounted on, for example, a hybrid vehicle in which a traveling motor and an internal combustion engine (not shown) generate driving force. In the case of a hybrid vehicle, for example, it may be a plug-in hybrid vehicle that can be charged from an external power source (such as a commercial power source) to the battery module 100. The battery module 100 may be provided, for example, under the passenger compartment of an electric vehicle. The battery module 100 may be provided, for example, in the passenger compartment or the luggage compartment of an electric vehicle.
[0020] The housing 101 is a component for housing and protecting a plurality of battery cells 110. The housing 101 is substantially rectangular in shape when viewed from above. The housing 101 may have, for example, an upper housing for covering the top of the plurality of battery cells 110 and a lower housing that contacts the bottom of the plurality of battery cells 110. The upper housing and the lower housing may be joined together, for example, by fastening each side.
[0021] The battery cell 110 is an energy storage device. The battery cell 110 is a secondary battery that utilizes ion intercalation. The battery cell 110 may be, for example, a lithium-ion secondary battery. The battery cell 110 may have a shape called a rectangular can cell, for example, as shown in Figure 2. In the case of a rectangular can cell, the positive electrode, negative electrode, separator, and electrolyte are housed in a rectangular metal casing. The battery cell 110 may also have a shape called a laminate cell, for example. In the case of a laminate cell, the positive electrode, negative electrode, separator, and electrolyte are housed in an outer casing made of a thin resin-metal composite film.
[0022] The battery cell 110 can be a lithium-ion secondary battery, or any other energy storage device capable of storing and releasing electricity, such as a capacitor, where the pressure applied to the main surface affects the battery characteristics, and therefore uniformity of the applied pressure is required.
[0023] The battery cell 110 has an electrode tab 110a and a main surface 110b. The electrode tab 110a is a component for electrically connecting the battery cell 110 to the outside. The electrode tab 110a is made of a conductive metal material. For example, copper, aluminum, etc., may be used for the electrode tab 110a. The electrode tab 110a is provided on the outer circumferential surface of the battery cell 110. For example, if the battery cell 110 is a rectangular can cell, the electrode tab 110a may be provided on the top surface. For example, if the battery cell 110 is a laminated cell, the electrode tab 110a may be provided on the side surface.
[0024] The main surface 110b is the surface of the battery cell 110 with the largest area. The main surfaces 110b may, for example, be provided opposite each other within the same battery cell 110. In this case, the pair of opposing main surfaces 110b may have the same area. Here, having the same area includes a design tolerance of approximately 5%. The main surface 110b may, for example, have multiple irregularities.
[0025] The heat exchanger 120 is a component for cooling or warming the battery cell 110 to a predetermined temperature during charging or discharging. This helps to prevent a decrease in the battery cell 110's lifespan and maintain its charge / discharge performance. The heat exchanger 120 is in contact with the battery cell 110 and can cool or warm the battery cell 110 by exchanging heat between the heat transfer medium and the battery cell 110. The heat exchanger 120 includes a heat exchange section 121, a distribution pipe 122, a consolidation pipe 123, and a spring (biasing member) 131.
[0026] The heat transfer medium is a fluid for transferring or receiving heat to or from the battery cell 110. For example, water can be used as the heat transfer medium. For example, a refrigerant can be used as the heat transfer medium. For example, HFCs (hydrofluorocarbons) or HFOs (hydrofluoroolefins) can be used as the refrigerant. For example, R-134a, R-410A, R245fa, and R-32 may be used for HFCs. For example, R-1233zd(E), R-1234yf, and R-1234ze(E) may be used for HFOs.
[0027] The heat exchange section 121 is a component that contacts the battery cell 110 and exchanges heat between the battery cell 110 and the heat transfer medium. The heat exchange section 121 has an inlet 121a, an outlet 121b, and a contact surface 121c. Heat can be transferred between the heat exchange section 121 and the battery cell 110 via the contact surface 121c. The heat exchange section 121 may be, for example, plate-shaped. The heat exchange section 121 may be formed using, for example, a metal material. The metal material used may be, for example, a material with high thermal conductivity. For example, an aluminum alloy can be used for the heat exchange section 121.
[0028] The distribution pipe 122 is a component that supplies coolant to multiple inlets 121a from outside the battery module 100. The consolidation pipe 123 is a component that discharges coolant to the outside of the battery module from multiple outlets 121b. The distribution pipe 122 and the consolidation pipe 123 may be made of the same material or different materials. The distribution pipe 122 and the consolidation pipe 123 may be made of resin material or metal material.
[0029] The spring 131 is a component that generates a compressive force to resist the force that causes the main surface 110b of the battery cell 110 to expand. The spring 131 is an elastic body. The spring 131 may be, for example, a spring made of a metal material. The spring 131 may be, for example, a coil shape. The spring 131 may be, for example, a leaf spring made by bending a plate. The spring 131 may be a torsion spring.
[0030] The spring constant of spring 131 may be set such that, for example, the spring 131 is arranged at a lower density in the first region 110c in the central part of the main surface 110b of the battery cell 110 than in the second region 110d in the vertical periphery. This makes it possible to equalize the temperature of the battery cell 110 and easily achieve uniformity of the reaction within the battery cell 110.
[0031] The spring constant of the spring 131 may be set such that the spring 131 in the first region 110c has a lower spring constant than the spring 131 in the second region 110d, for example, by using different materials for the spring 131 in the first region 110c and the spring 131 in the second region 110d. The material of the spring 131 in the first region 110c may have lower material stiffness than the material of the spring 131 in the second region 110d. This makes it possible to equalize the temperature of the battery cell 110 and easily achieve uniformity of the reaction within the battery cell 110.
[0032] The spring 131 may, for example, be positioned parallel to the direction of flow of the heat transfer medium when close to the distribution pipe 122. The spring 131 may, for example, be positioned to obstruct the flow of the heat transfer medium when close to the consolidation pipe 123. Here, being positioned to obstruct the flow of the heat transfer medium means, for example, that instead of arranging multiple springs 131 in a line in the width direction of the heat exchange section 121, they are offset so that the line connecting the center points of two adjacent springs 131 in the width direction of the heat exchange section 121 intersects the width direction of the heat exchange section 121. This makes it possible to equalize the temperature of the battery cell 110 and easily achieve uniformity of the reaction within the battery cell 110.
[0033] (Embodiment 1) The battery module 100 of Embodiment 1, as schematically shown in Figure 1, has a number of battery cells 110 and a heat exchanger 120 housed in a casing 101. The battery cells 110 are of a type such as a rectangular can cell, as shown in Figure 2, with electrode tabs 110a on their upper surfaces. The heat exchange section 121 of the heat exchanger 120, which will be described later, is interposed between the opposing main surfaces 110b of each battery cell 110.
[0034] In Figure 1, for convenience, each battery cell 110 and the heat exchange section 121 of the heat exchange device 120 are depicted with a gap between them. However, in reality, they are installed so that they are in close contact, allowing the heat generated in the battery cells 110 to be transferred to the heat exchange section 121.
[0035] The heat exchange section 121 of the heat exchange device 120 has, for example, an inlet 121a through which coolant flows in from the distribution pipe 122 and an outlet 121b through which the coolant is discharged to the aggregation pipe 123, as shown in Figure 3. The side surface between the inlet 121a and the outlet 121b is a contact surface 121c that is in close contact with the main surface 110b of the battery cell 110. Inside the heat exchange section 121, a spring 131, as shown in Figure 4, is provided to apply pressure to the contact surface 121c against the main surface 110b of the battery cell 110.
[0036] More specifically, as shown in Figure 5, for example, the spring 131 is arranged such that the first region 110c, which accounts for about 60% of the central part in the vertical direction of the main surface 110b of the battery cell 110, is denser than the second region 110d, which accounts for about 20% of the peripheral part in the vertical direction. The spring constant for the force pressing on the main surface 110b of the battery cell 110 and the spring constant for the deflection are set to be smaller in the first region 110c than in the second region 110d. In other words, for example, when the main surface 110b of the battery cell 110 expands due to internal reactions or heat generation during charging and discharging, the displacement of the main surface 110b of the battery cell 110 is greater in the central first region 110c than in the peripheral second region 110d. However, because the spring constant is set to be smaller in the first region 110c than in the second region 110d, the influence of the magnitude of the displacement due to the expansion and contraction of the battery cell 110 and the influence of the magnitude of the spring constant cancel each other out.
[0037] In other words, the increase in the pressurizing force in the first region 110c is suppressed relative to the magnitude of the displacement, and the pressurizing force on the main surface 110b is made uniform. Therefore, it is easy to make the reaction within the battery cell 110 uniform. Note that the effects of the magnitude of the displacement of the battery cell 110 and the magnitude of the spring constant do not necessarily have to be completely canceled out, and the non-uniformity may be reduced as needed.
[0038] (modified version) The spring constant may be set not only to determine the pressing force acting on the main surface 110b of the battery cell 110 as described above, but also taking other factors into consideration. For example, generally, a large amount of heat is generated near the electrode tab 110a of the battery cell 110, so it is preferable to ensure a sufficient flow rate of the coolant in the heat exchanger 120.
[0039] Therefore, in the third region near the electrode tab 110a of the battery cell 110 on the contact surface 121c of the heat exchange section 121, the spring constant may be set to be even larger than in the second region 110d, so that even when the force of expansion of the battery cell 110 acts on it, the heat exchange section 121 is less likely to deform and the flow path of the coolant is less likely to be narrowed. This makes it possible to equalize the temperature of the battery cell 110 and easily achieve uniformity of the reaction inside the battery cell 110.
[0040] (Embodiment 2) The spring constant setting described above is not limited to the battery module 100 using the rectangular cell type battery cell 110 described above, but can be applied to battery modules 100 using various types of battery cells 110. For example, the battery module 100 of Embodiment 2 uses so-called laminated type battery cells 110, as schematically shown in Figure 6. The above battery cell 110 is provided with electrode tabs 110a on both the left and right sides in Figure 7, as shown by extracting and drawing only two of them in the figure. The arrangement such that the heat exchange section 121 of the heat exchange device 120 is interposed between the opposing main surfaces 110b of each battery cell 110 is the same as in Embodiment 1.
[0041] Inside the heat exchange section 121, as shown in Figures 8 and 9, for example, the springs 131 are arranged at a lower density in the first region 110c, which occupies about 60% of the central part in the left-right direction of the main surface 110b of the battery cell 110, than in the second region 110d, which occupies about 20% of the peripheral part in the left-right direction. The spring constant for the force pressing on the main surface 110b of the battery cell 110 is set to be smaller in the first region 110c than in the second region 110d. As a result, the magnitude of the displacement of the main surface 110b and the magnitude of the spring constant cancel each other out, meaning that the increase in the pressing force in the first region 110c is suppressed relative to the magnitude of the displacement, and the pressure applied to the main surface 110b is made uniform. Therefore, it is easy to make the reaction within the battery cell 110 uniform.
[0042] (Other matters) The spring 131 that presses the main surface 110b of the battery cell 110 with the contact surface 121c of the heat exchange section 121 is not limited to the above, and various springs can be applied, such as the one shown in Figure 10. Furthermore, the spring constant is not limited to being set by the arrangement density of the springs, but may also be set by various factors such as the type and dimensions of the spring, the material (e.g., thin stainless steel sheet, hard steel, etc.), and the support method. Here, if multiple springs are provided, the above spring constant means that it is the combined spring constant of the neighboring springs.
[0043] Furthermore, the spring constant for the force and deflection applied by the heat exchange section 121 of the heat exchange device 120 to the main surface 110b of the battery cell 110 is not determined solely by the spring 131, but may be determined comprehensively, taking into account factors such as the rigidity of the main surface 110b of the battery cell 110 and the contact surface 121c of the heat exchange section 121 itself, as well as providing areas with high rigidity, such as ribs or gussets, in order to ensure uniformity of the applied pressure to the laminate inside the battery cell 110.
[0044] Furthermore, in the example above, the first region 110c and the second region 110d were shown as regions aligned in one dimension, but essentially the same effect can be obtained even if these are regions that extend in two dimensions. [Explanation of symbols]
[0045] 100 Battery Modules 101 cabinets 110 battery cells 110a Electrode Tab 110b main surface 110c 1st area 110d 2nd area 120 Heat exchange equipment 121 Heat exchange section 121a Inlet 121b Outlet 121c Contact surface 122 Distribution piping 123 Centralized Piping 131 Spring (Biasing Member)
Claims
1. A heat exchange device for a battery cell having a contact surface that contacts a battery cell having a main surface, wherein heat is transferred from the main surface through the contact surface, The contact surface is configured to generate a pressing force that resists the force in the direction that causes the main surface of the battery cell to expand. A heat exchange device for a battery cell, characterized in that the pressure applied is set to be smaller at a position corresponding to a first region in the center of the main surface than at a position corresponding to a second region in the periphery.
2. A heat exchange device for a battery cell according to claim 1, A biasing member is provided on the inner side of the contact surface at positions corresponding to the first and second regions, which generates a pressing force that resists the force in the direction that causes the main surface of the battery cell to expand. A heat exchange device for a battery cell, characterized in that the spring constant of the biasing member provided at a position corresponding to the first region is set to be smaller than the spring constant of the biasing member provided at a position corresponding to the second region.
3. A heat exchange device for a battery cell according to claim 1, A heat exchange device for a battery cell, characterized in that the spring constant at the position corresponding to the electrode tab of the battery cell is set to be greater than that at the position corresponding to the second region.
4. A heat exchange device for a battery cell according to claim 3, A heat exchanger for a battery cell, characterized in that the spring constant at the position corresponding to the electrode tab of the battery cell is a spring constant that includes the influence of the rigidity of the heat exchanger housing and / or ribs provided on the housing.
5. A battery cell having a main surface, A heat exchanger for a battery cell having a contact surface that contacts the battery cell, and heat being transferred from the main surface through the contact surface, A battery module having, The contact surface is configured to generate a pressing force that resists the force in the direction that causes the main surface of the battery cell to expand. A battery module characterized in that the pressure applied is set to be smaller at a position corresponding to a first region in the central part of the main surface than at a position corresponding to a second region in the periphery.
6. A battery module according to claim 5, A biasing member is provided on the inner side of the contact surface at positions corresponding to the first and second regions, which generates a pressing force that resists the force in the direction that causes the main surface of the battery cell to expand. A battery module characterized in that the spring constant of the biasing member provided at a position corresponding to the first region is set to be smaller than the spring constant of the biasing member provided at a position corresponding to the second region.
7. A battery module according to claim 5, A battery module characterized in that the spring constant at the position corresponding to the electrode tab of the battery cell is set to be greater than that at the position corresponding to the second region.
8. A battery module according to claim 7, The battery module is characterized in that the spring constant at the position corresponding to the electrode tab of the battery cell is a spring constant that includes the influence of the rigidity of the heat exchanger housing and / or ribs provided on the housing.